+++ /dev/null
-Bug hunting
-+++++++++++
-
-Last updated: 20 December 2005
-
-Introduction
-============
-
-Always try the latest kernel from kernel.org and build from source. If you are
-not confident in doing that please report the bug to your distribution vendor
-instead of to a kernel developer.
-
-Finding bugs is not always easy. Have a go though. If you can't find it don't
-give up. Report as much as you have found to the relevant maintainer. See
-MAINTAINERS for who that is for the subsystem you have worked on.
-
-Before you submit a bug report read
-:ref:`Documentation/REPORTING-BUGS <reportingbugs>`.
-
-Devices not appearing
-=====================
-
-Often this is caused by udev. Check that first before blaming it on the
-kernel.
-
-Finding patch that caused a bug
-===============================
-
-
-
-Finding using ``git-bisect``
-----------------------------
-
-Using the provided tools with ``git`` makes finding bugs easy provided the bug
-is reproducible.
-
-Steps to do it:
-
-- start using git for the kernel source
-- read the man page for ``git-bisect``
-- have fun
-
-Finding it the old way
-----------------------
-
-[Sat Mar 2 10:32:33 PST 1996 KERNEL_BUG-HOWTO lm@sgi.com (Larry McVoy)]
-
-This is how to track down a bug if you know nothing about kernel hacking.
-It's a brute force approach but it works pretty well.
-
-You need:
-
- - A reproducible bug - it has to happen predictably (sorry)
- - All the kernel tar files from a revision that worked to the
- revision that doesn't
-
-You will then do:
-
- - Rebuild a revision that you believe works, install, and verify that.
- - Do a binary search over the kernels to figure out which one
- introduced the bug. I.e., suppose 1.3.28 didn't have the bug, but
- you know that 1.3.69 does. Pick a kernel in the middle and build
- that, like 1.3.50. Build & test; if it works, pick the mid point
- between .50 and .69, else the mid point between .28 and .50.
- - You'll narrow it down to the kernel that introduced the bug. You
- can probably do better than this but it gets tricky.
-
- - Narrow it down to a subdirectory
-
- - Copy kernel that works into "test". Let's say that 3.62 works,
- but 3.63 doesn't. So you diff -r those two kernels and come
- up with a list of directories that changed. For each of those
- directories:
-
- Copy the non-working directory next to the working directory
- as "dir.63".
- One directory at time, try moving the working directory to
- "dir.62" and mv dir.63 dir"time, try::
-
- mv dir dir.62
- mv dir.63 dir
- find dir -name '*.[oa]' -print | xargs rm -f
-
- And then rebuild and retest. Assuming that all related
- changes were contained in the sub directory, this should
- isolate the change to a directory.
-
- Problems: changes in header files may have occurred; I've
- found in my case that they were self explanatory - you may
- or may not want to give up when that happens.
-
- - Narrow it down to a file
-
- - You can apply the same technique to each file in the directory,
- hoping that the changes in that file are self contained.
-
- - Narrow it down to a routine
-
- - You can take the old file and the new file and manually create
- a merged file that has::
-
- #ifdef VER62
- routine()
- {
- ...
- }
- #else
- routine()
- {
- ...
- }
- #endif
-
- And then walk through that file, one routine at a time and
- prefix it with::
-
- #define VER62
- /* both routines here */
- #undef VER62
-
- Then recompile, retest, move the ifdefs until you find the one
- that makes the difference.
-
-Finally, you take all the info that you have, kernel revisions, bug
-description, the extent to which you have narrowed it down, and pass
-that off to whomever you believe is the maintainer of that section.
-A post to linux.dev.kernel isn't such a bad idea if you've done some
-work to narrow it down.
-
-If you get it down to a routine, you'll probably get a fix in 24 hours.
-
-My apologies to Linus and the other kernel hackers for describing this
-brute force approach, it's hardly what a kernel hacker would do. However,
-it does work and it lets non-hackers help fix bugs. And it is cool
-because Linux snapshots will let you do this - something that you can't
-do with vendor supplied releases.
-
-Fixing the bug
-==============
-
-Nobody is going to tell you how to fix bugs. Seriously. You need to work it
-out. But below are some hints on how to use the tools.
-
-To debug a kernel, use objdump and look for the hex offset from the crash
-output to find the valid line of code/assembler. Without debug symbols, you
-will see the assembler code for the routine shown, but if your kernel has
-debug symbols the C code will also be available. (Debug symbols can be enabled
-in the kernel hacking menu of the menu configuration.) For example::
-
- objdump -r -S -l --disassemble net/dccp/ipv4.o
-
-.. note::
-
- You need to be at the top level of the kernel tree for this to pick up
- your C files.
-
-If you don't have access to the code you can also debug on some crash dumps
-e.g. crash dump output as shown by Dave Miller::
-
- EIP is at ip_queue_xmit+0x14/0x4c0
- ...
- Code: 44 24 04 e8 6f 05 00 00 e9 e8 fe ff ff 8d 76 00 8d bc 27 00 00
- 00 00 55 57 56 53 81 ec bc 00 00 00 8b ac 24 d0 00 00 00 8b 5d 08
- <8b> 83 3c 01 00 00 89 44 24 14 8b 45 28 85 c0 89 44 24 18 0f 85
-
- Put the bytes into a "foo.s" file like this:
-
- .text
- .globl foo
- foo:
- .byte .... /* bytes from Code: part of OOPS dump */
-
- Compile it with "gcc -c -o foo.o foo.s" then look at the output of
- "objdump --disassemble foo.o".
-
- Output:
-
- ip_queue_xmit:
- push %ebp
- push %edi
- push %esi
- push %ebx
- sub $0xbc, %esp
- mov 0xd0(%esp), %ebp ! %ebp = arg0 (skb)
- mov 0x8(%ebp), %ebx ! %ebx = skb->sk
- mov 0x13c(%ebx), %eax ! %eax = inet_sk(sk)->opt
-
-In addition, you can use GDB to figure out the exact file and line
-number of the OOPS from the ``vmlinux`` file. If you have
-``CONFIG_DEBUG_INFO`` enabled, you can simply copy the EIP value from the
-OOPS::
-
- EIP: 0060:[<c021e50e>] Not tainted VLI
-
-And use GDB to translate that to human-readable form::
-
- gdb vmlinux
- (gdb) l *0xc021e50e
-
-If you don't have ``CONFIG_DEBUG_INFO`` enabled, you use the function
-offset from the OOPS::
-
- EIP is at vt_ioctl+0xda8/0x1482
-
-And recompile the kernel with ``CONFIG_DEBUG_INFO`` enabled::
-
- make vmlinux
- gdb vmlinux
- (gdb) p vt_ioctl
- (gdb) l *(0x<address of vt_ioctl> + 0xda8)
-
-or, as one command::
-
- (gdb) l *(vt_ioctl + 0xda8)
-
-If you have a call trace, such as::
-
- Call Trace:
- [<ffffffff8802c8e9>] :jbd:log_wait_commit+0xa3/0xf5
- [<ffffffff810482d9>] autoremove_wake_function+0x0/0x2e
- [<ffffffff8802770b>] :jbd:journal_stop+0x1be/0x1ee
- ...
-
-this shows the problem in the :jbd: module. You can load that module in gdb
-and list the relevant code::
-
- gdb fs/jbd/jbd.ko
- (gdb) p log_wait_commit
- (gdb) l *(0x<address> + 0xa3)
-
-or::
-
- (gdb) l *(log_wait_commit + 0xa3)
-
-
-Another very useful option of the Kernel Hacking section in menuconfig is
-Debug memory allocations. This will help you see whether data has been
-initialised and not set before use etc. To see the values that get assigned
-with this look at ``mm/slab.c`` and search for ``POISON_INUSE``. When using
-this an Oops will often show the poisoned data instead of zero which is the
-default.
-
-Once you have worked out a fix please submit it upstream. After all open
-source is about sharing what you do and don't you want to be recognised for
-your genius?
-
-Please do read :ref:`Documentation/SubmittingPatches <submittingpatches>`
-though to help your code get accepted.
+++ /dev/null
-.. _securitybugs:
-
-Security bugs
-=============
-
-Linux kernel developers take security very seriously. As such, we'd
-like to know when a security bug is found so that it can be fixed and
-disclosed as quickly as possible. Please report security bugs to the
-Linux kernel security team.
-
-1) Contact
-----------
-
-The Linux kernel security team can be contacted by email at
-<security@kernel.org>. This is a private list of security officers
-who will help verify the bug report and develop and release a fix.
-It is possible that the security team will bring in extra help from
-area maintainers to understand and fix the security vulnerability.
-
-As it is with any bug, the more information provided the easier it
-will be to diagnose and fix. Please review the procedure outlined in
-REPORTING-BUGS if you are unclear about what information is helpful.
-Any exploit code is very helpful and will not be released without
-consent from the reporter unless it has already been made public.
-
-2) Disclosure
--------------
-
-The goal of the Linux kernel security team is to work with the
-bug submitter to bug resolution as well as disclosure. We prefer
-to fully disclose the bug as soon as possible. It is reasonable to
-delay disclosure when the bug or the fix is not yet fully understood,
-the solution is not well-tested or for vendor coordination. However, we
-expect these delays to be short, measurable in days, not weeks or months.
-A disclosure date is negotiated by the security team working with the
-bug submitter as well as vendors. However, the kernel security team
-holds the final say when setting a disclosure date. The timeframe for
-disclosure is from immediate (esp. if it's already publicly known)
-to a few weeks. As a basic default policy, we expect report date to
-disclosure date to be on the order of 7 days.
-
-3) Non-disclosure agreements
-----------------------------
-
-The Linux kernel security team is not a formal body and therefore unable
-to enter any non-disclosure agreements.
+++ /dev/null
-Software cursor for VGA
-=======================
-
-by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
-and Martin Mares <mj@atrey.karlin.mff.cuni.cz>
-
-Linux now has some ability to manipulate cursor appearance. Normally, you
-can set the size of hardware cursor (and also work around some ugly bugs in
-those miserable Trident cards [#f1]_. You can now play a few new tricks:
-you can make your cursor look
-
-like a non-blinking red block, make it inverse background of the character it's
-over or to highlight that character and still choose whether the original
-hardware cursor should remain visible or not. There may be other things I have
-never thought of.
-
-The cursor appearance is controlled by a ``<ESC>[?1;2;3c`` escape sequence
-where 1, 2 and 3 are parameters described below. If you omit any of them,
-they will default to zeroes.
-
-first Parameter
- specifies cursor size::
-
- 0=default
- 1=invisible
- 2=underline,
- ...
- 8=full block
- + 16 if you want the software cursor to be applied
- + 32 if you want to always change the background color
- + 64 if you dislike having the background the same as the
- foreground.
-
- Highlights are ignored for the last two flags.
-
-second parameter
- selects character attribute bits you want to change
- (by simply XORing them with the value of this parameter). On standard
- VGA, the high four bits specify background and the low four the
- foreground. In both groups, low three bits set color (as in normal
- color codes used by the console) and the most significant one turns
- on highlight (or sometimes blinking -- it depends on the configuration
- of your VGA).
-
-third parameter
- consists of character attribute bits you want to set.
-
- Bit setting takes place before bit toggling, so you can simply clear a
- bit by including it in both the set mask and the toggle mask.
-
-.. [#f1] see ``#define TRIDENT_GLITCH`` in ``drivers/video/vgacon.c``.
-
-Examples:
-=========
-
-To get normal blinking underline, use::
-
- echo -e '\033[?2c'
-
-To get blinking block, use::
-
- echo -e '\033[?6c'
-
-To get red non-blinking block, use::
-
- echo -e '\033[?17;0;64c'
--- /dev/null
+Linux kernel release 4.x <http://kernel.org/>
+=============================================
+
+These are the release notes for Linux version 4. Read them carefully,
+as they tell you what this is all about, explain how to install the
+kernel, and what to do if something goes wrong.
+
+What is Linux?
+--------------
+
+ Linux is a clone of the operating system Unix, written from scratch by
+ Linus Torvalds with assistance from a loosely-knit team of hackers across
+ the Net. It aims towards POSIX and Single UNIX Specification compliance.
+
+ It has all the features you would expect in a modern fully-fledged Unix,
+ including true multitasking, virtual memory, shared libraries, demand
+ loading, shared copy-on-write executables, proper memory management,
+ and multistack networking including IPv4 and IPv6.
+
+ It is distributed under the GNU General Public License - see the
+ accompanying COPYING file for more details.
+
+On what hardware does it run?
+-----------------------------
+
+ Although originally developed first for 32-bit x86-based PCs (386 or higher),
+ today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
+ UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
+ IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
+ Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures.
+
+ Linux is easily portable to most general-purpose 32- or 64-bit architectures
+ as long as they have a paged memory management unit (PMMU) and a port of the
+ GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
+ also been ported to a number of architectures without a PMMU, although
+ functionality is then obviously somewhat limited.
+ Linux has also been ported to itself. You can now run the kernel as a
+ userspace application - this is called UserMode Linux (UML).
+
+Documentation
+-------------
+
+ - There is a lot of documentation available both in electronic form on
+ the Internet and in books, both Linux-specific and pertaining to
+ general UNIX questions. I'd recommend looking into the documentation
+ subdirectories on any Linux FTP site for the LDP (Linux Documentation
+ Project) books. This README is not meant to be documentation on the
+ system: there are much better sources available.
+
+ - There are various README files in the Documentation/ subdirectory:
+ these typically contain kernel-specific installation notes for some
+ drivers for example. See Documentation/00-INDEX for a list of what
+ is contained in each file. Please read the Changes file, as it
+ contains information about the problems, which may result by upgrading
+ your kernel.
+
+ - The Documentation/DocBook/ subdirectory contains several guides for
+ kernel developers and users. These guides can be rendered in a
+ number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
+ After installation, ``make psdocs``, ``make pdfdocs``, ``make htmldocs``,
+ or ``make mandocs`` will render the documentation in the requested format.
+
+Installing the kernel source
+----------------------------
+
+ - If you install the full sources, put the kernel tarball in a
+ directory where you have permissions (e.g. your home directory) and
+ unpack it::
+
+ xz -cd linux-4.X.tar.xz | tar xvf -
+
+ Replace "X" with the version number of the latest kernel.
+
+ Do NOT use the /usr/src/linux area! This area has a (usually
+ incomplete) set of kernel headers that are used by the library header
+ files. They should match the library, and not get messed up by
+ whatever the kernel-du-jour happens to be.
+
+ - You can also upgrade between 4.x releases by patching. Patches are
+ distributed in the xz format. To install by patching, get all the
+ newer patch files, enter the top level directory of the kernel source
+ (linux-4.X) and execute::
+
+ xz -cd ../patch-4.x.xz | patch -p1
+
+ Replace "x" for all versions bigger than the version "X" of your current
+ source tree, **in_order**, and you should be ok. You may want to remove
+ the backup files (some-file-name~ or some-file-name.orig), and make sure
+ that there are no failed patches (some-file-name# or some-file-name.rej).
+ If there are, either you or I have made a mistake.
+
+ Unlike patches for the 4.x kernels, patches for the 4.x.y kernels
+ (also known as the -stable kernels) are not incremental but instead apply
+ directly to the base 4.x kernel. For example, if your base kernel is 4.0
+ and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1
+ and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and
+ want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is,
+ patch -R) **before** applying the 4.0.3 patch. You can read more on this in
+ :ref:`Documentation/applying-patches.txt <applying_patches>`.
+
+ Alternatively, the script patch-kernel can be used to automate this
+ process. It determines the current kernel version and applies any
+ patches found::
+
+ linux/scripts/patch-kernel linux
+
+ The first argument in the command above is the location of the
+ kernel source. Patches are applied from the current directory, but
+ an alternative directory can be specified as the second argument.
+
+ - Make sure you have no stale .o files and dependencies lying around::
+
+ cd linux
+ make mrproper
+
+ You should now have the sources correctly installed.
+
+Software requirements
+---------------------
+
+ Compiling and running the 4.x kernels requires up-to-date
+ versions of various software packages. Consult
+ :ref:`Documentation/Changes <changes>` for the minimum version numbers
+ required and how to get updates for these packages. Beware that using
+ excessively old versions of these packages can cause indirect
+ errors that are very difficult to track down, so don't assume that
+ you can just update packages when obvious problems arise during
+ build or operation.
+
+Build directory for the kernel
+------------------------------
+
+ When compiling the kernel, all output files will per default be
+ stored together with the kernel source code.
+ Using the option ``make O=output/dir`` allows you to specify an alternate
+ place for the output files (including .config).
+ Example::
+
+ kernel source code: /usr/src/linux-4.X
+ build directory: /home/name/build/kernel
+
+ To configure and build the kernel, use::
+
+ cd /usr/src/linux-4.X
+ make O=/home/name/build/kernel menuconfig
+ make O=/home/name/build/kernel
+ sudo make O=/home/name/build/kernel modules_install install
+
+ Please note: If the ``O=output/dir`` option is used, then it must be
+ used for all invocations of make.
+
+Configuring the kernel
+----------------------
+
+ Do not skip this step even if you are only upgrading one minor
+ version. New configuration options are added in each release, and
+ odd problems will turn up if the configuration files are not set up
+ as expected. If you want to carry your existing configuration to a
+ new version with minimal work, use ``make oldconfig``, which will
+ only ask you for the answers to new questions.
+
+ - Alternative configuration commands are::
+
+ "make config" Plain text interface.
+
+ "make menuconfig" Text based color menus, radiolists & dialogs.
+
+ "make nconfig" Enhanced text based color menus.
+
+ "make xconfig" Qt based configuration tool.
+
+ "make gconfig" GTK+ based configuration tool.
+
+ "make oldconfig" Default all questions based on the contents of
+ your existing ./.config file and asking about
+ new config symbols.
+
+ "make silentoldconfig"
+ Like above, but avoids cluttering the screen
+ with questions already answered.
+ Additionally updates the dependencies.
+
+ "make olddefconfig"
+ Like above, but sets new symbols to their default
+ values without prompting.
+
+ "make defconfig" Create a ./.config file by using the default
+ symbol values from either arch/$ARCH/defconfig
+ or arch/$ARCH/configs/${PLATFORM}_defconfig,
+ depending on the architecture.
+
+ "make ${PLATFORM}_defconfig"
+ Create a ./.config file by using the default
+ symbol values from
+ arch/$ARCH/configs/${PLATFORM}_defconfig.
+ Use "make help" to get a list of all available
+ platforms of your architecture.
+
+ "make allyesconfig"
+ Create a ./.config file by setting symbol
+ values to 'y' as much as possible.
+
+ "make allmodconfig"
+ Create a ./.config file by setting symbol
+ values to 'm' as much as possible.
+
+ "make allnoconfig" Create a ./.config file by setting symbol
+ values to 'n' as much as possible.
+
+ "make randconfig" Create a ./.config file by setting symbol
+ values to random values.
+
+ "make localmodconfig" Create a config based on current config and
+ loaded modules (lsmod). Disables any module
+ option that is not needed for the loaded modules.
+
+ To create a localmodconfig for another machine,
+ store the lsmod of that machine into a file
+ and pass it in as a LSMOD parameter.
+
+ target$ lsmod > /tmp/mylsmod
+ target$ scp /tmp/mylsmod host:/tmp
+
+ host$ make LSMOD=/tmp/mylsmod localmodconfig
+
+ The above also works when cross compiling.
+
+ "make localyesconfig" Similar to localmodconfig, except it will convert
+ all module options to built in (=y) options.
+
+ You can find more information on using the Linux kernel config tools
+ in Documentation/kbuild/kconfig.txt.
+
+ - NOTES on ``make config``:
+
+ - Having unnecessary drivers will make the kernel bigger, and can
+ under some circumstances lead to problems: probing for a
+ nonexistent controller card may confuse your other controllers
+
+ - A kernel with math-emulation compiled in will still use the
+ coprocessor if one is present: the math emulation will just
+ never get used in that case. The kernel will be slightly larger,
+ but will work on different machines regardless of whether they
+ have a math coprocessor or not.
+
+ - The "kernel hacking" configuration details usually result in a
+ bigger or slower kernel (or both), and can even make the kernel
+ less stable by configuring some routines to actively try to
+ break bad code to find kernel problems (kmalloc()). Thus you
+ should probably answer 'n' to the questions for "development",
+ "experimental", or "debugging" features.
+
+Compiling the kernel
+--------------------
+
+ - Make sure you have at least gcc 3.2 available.
+ For more information, refer to :ref:`Documentation/Changes <changes>`.
+
+ Please note that you can still run a.out user programs with this kernel.
+
+ - Do a ``make`` to create a compressed kernel image. It is also
+ possible to do ``make install`` if you have lilo installed to suit the
+ kernel makefiles, but you may want to check your particular lilo setup first.
+
+ To do the actual install, you have to be root, but none of the normal
+ build should require that. Don't take the name of root in vain.
+
+ - If you configured any of the parts of the kernel as ``modules``, you
+ will also have to do ``make modules_install``.
+
+ - Verbose kernel compile/build output:
+
+ Normally, the kernel build system runs in a fairly quiet mode (but not
+ totally silent). However, sometimes you or other kernel developers need
+ to see compile, link, or other commands exactly as they are executed.
+ For this, use "verbose" build mode. This is done by passing
+ ``V=1`` to the ``make`` command, e.g.::
+
+ make V=1 all
+
+ To have the build system also tell the reason for the rebuild of each
+ target, use ``V=2``. The default is ``V=0``.
+
+ - Keep a backup kernel handy in case something goes wrong. This is
+ especially true for the development releases, since each new release
+ contains new code which has not been debugged. Make sure you keep a
+ backup of the modules corresponding to that kernel, as well. If you
+ are installing a new kernel with the same version number as your
+ working kernel, make a backup of your modules directory before you
+ do a ``make modules_install``.
+
+ Alternatively, before compiling, use the kernel config option
+ "LOCALVERSION" to append a unique suffix to the regular kernel version.
+ LOCALVERSION can be set in the "General Setup" menu.
+
+ - In order to boot your new kernel, you'll need to copy the kernel
+ image (e.g. .../linux/arch/x86/boot/bzImage after compilation)
+ to the place where your regular bootable kernel is found.
+
+ - Booting a kernel directly from a floppy without the assistance of a
+ bootloader such as LILO, is no longer supported.
+
+ If you boot Linux from the hard drive, chances are you use LILO, which
+ uses the kernel image as specified in the file /etc/lilo.conf. The
+ kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
+ /boot/bzImage. To use the new kernel, save a copy of the old image
+ and copy the new image over the old one. Then, you MUST RERUN LILO
+ to update the loading map! If you don't, you won't be able to boot
+ the new kernel image.
+
+ Reinstalling LILO is usually a matter of running /sbin/lilo.
+ You may wish to edit /etc/lilo.conf to specify an entry for your
+ old kernel image (say, /vmlinux.old) in case the new one does not
+ work. See the LILO docs for more information.
+
+ After reinstalling LILO, you should be all set. Shutdown the system,
+ reboot, and enjoy!
+
+ If you ever need to change the default root device, video mode,
+ ramdisk size, etc. in the kernel image, use the ``rdev`` program (or
+ alternatively the LILO boot options when appropriate). No need to
+ recompile the kernel to change these parameters.
+
+ - Reboot with the new kernel and enjoy.
+
+If something goes wrong
+-----------------------
+
+ - If you have problems that seem to be due to kernel bugs, please check
+ the file MAINTAINERS to see if there is a particular person associated
+ with the part of the kernel that you are having trouble with. If there
+ isn't anyone listed there, then the second best thing is to mail
+ them to me (torvalds@linux-foundation.org), and possibly to any other
+ relevant mailing-list or to the newsgroup.
+
+ - In all bug-reports, *please* tell what kernel you are talking about,
+ how to duplicate the problem, and what your setup is (use your common
+ sense). If the problem is new, tell me so, and if the problem is
+ old, please try to tell me when you first noticed it.
+
+ - If the bug results in a message like::
+
+ unable to handle kernel paging request at address C0000010
+ Oops: 0002
+ EIP: 0010:XXXXXXXX
+ eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
+ esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
+ ds: xxxx es: xxxx fs: xxxx gs: xxxx
+ Pid: xx, process nr: xx
+ xx xx xx xx xx xx xx xx xx xx
+
+ or similar kernel debugging information on your screen or in your
+ system log, please duplicate it *exactly*. The dump may look
+ incomprehensible to you, but it does contain information that may
+ help debugging the problem. The text above the dump is also
+ important: it tells something about why the kernel dumped code (in
+ the above example, it's due to a bad kernel pointer). More information
+ on making sense of the dump is in Documentation/oops-tracing.txt
+
+ - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
+ as is, otherwise you will have to use the ``ksymoops`` program to make
+ sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
+ This utility can be downloaded from
+ ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
+ Alternatively, you can do the dump lookup by hand:
+
+ - In debugging dumps like the above, it helps enormously if you can
+ look up what the EIP value means. The hex value as such doesn't help
+ me or anybody else very much: it will depend on your particular
+ kernel setup. What you should do is take the hex value from the EIP
+ line (ignore the ``0010:``), and look it up in the kernel namelist to
+ see which kernel function contains the offending address.
+
+ To find out the kernel function name, you'll need to find the system
+ binary associated with the kernel that exhibited the symptom. This is
+ the file 'linux/vmlinux'. To extract the namelist and match it against
+ the EIP from the kernel crash, do::
+
+ nm vmlinux | sort | less
+
+ This will give you a list of kernel addresses sorted in ascending
+ order, from which it is simple to find the function that contains the
+ offending address. Note that the address given by the kernel
+ debugging messages will not necessarily match exactly with the
+ function addresses (in fact, that is very unlikely), so you can't
+ just 'grep' the list: the list will, however, give you the starting
+ point of each kernel function, so by looking for the function that
+ has a starting address lower than the one you are searching for but
+ is followed by a function with a higher address you will find the one
+ you want. In fact, it may be a good idea to include a bit of
+ "context" in your problem report, giving a few lines around the
+ interesting one.
+
+ If you for some reason cannot do the above (you have a pre-compiled
+ kernel image or similar), telling me as much about your setup as
+ possible will help. Please read the :ref:`REPORTING-BUGS <reportingbugs>`
+ document for details.
+
+ - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
+ cannot change values or set break points.) To do this, first compile the
+ kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make
+ clean``. You'll also need to enable CONFIG_PROC_FS (via ``make config``).
+
+ After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``.
+ You can now use all the usual gdb commands. The command to look up the
+ point where your system crashed is ``l *0xXXXXXXXX``. (Replace the XXXes
+ with the EIP value.)
+
+ gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly)
+ disregards the starting offset for which the kernel is compiled.
--- /dev/null
+How to deal with bad memory e.g. reported by memtest86+ ?
+=========================================================
+
+March 2008
+Jan-Simon Moeller, dl9pf@gmx.de
+
+
+
+There are three possibilities I know of:
+
+1) Reinsert/swap the memory modules
+
+2) Buy new modules (best!) or try to exchange the memory
+ if you have spare-parts
+
+3) Use BadRAM or memmap
+
+This Howto is about number 3) .
+
+
+BadRAM
+######
+
+BadRAM is the actively developed and available as kernel-patch
+here: http://rick.vanrein.org/linux/badram/
+
+For more details see the BadRAM documentation.
+
+memmap
+######
+
+memmap is already in the kernel and usable as kernel-parameter at
+boot-time. Its syntax is slightly strange and you may need to
+calculate the values by yourself!
+
+Syntax to exclude a memory area (see kernel-parameters.txt for details)::
+
+ memmap=<size>$<address>
+
+Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
+some others. All had 0x1869xxxx in common, so I chose a pattern of
+0x18690000,0xffff0000.
+
+With the numbers of the example above::
+
+ memmap=64K$0x18690000
+
+or::
+
+ memmap=0x10000$0x18690000
--- /dev/null
+Basic kernel profiling
+======================
+
+
+These instructions are deliberately very basic. If you want something clever,
+go read the real docs ;-)
+
+Please don't add more stuff, but feel free to
+correct my mistakes ;-) (mbligh@aracnet.com)
+
+Thanks to John Levon, Dave Hansen, et al. for help writing this.
+
+``<test>`` is the thing you're trying to measure.
+Make sure you have the correct ``System.map`` / ``vmlinux`` referenced!
+
+It is probably easiest to use ``make install`` for linux and hack
+``/sbin/installkernel`` to copy ``vmlinux`` to ``/boot``, in addition to
+``vmlinuz``, ``config``, ``System.map``, which are usually installed by default.
+
+Readprofile
+-----------
+
+A recent ``readprofile`` command is needed for 2.6, such as found in util-linux
+2.12a, which can be downloaded from:
+
+ http://www.kernel.org/pub/linux/utils/util-linux/
+
+Most distributions will ship it already.
+
+Add ``profile=2`` to the kernel command line.
+
+Some ``readprofile`` commands::
+
+ clear readprofile -r
+ <test>
+ dump output readprofile -m /boot/System.map > captured_profile
+
+Oprofile
+--------
+
+Get the source (see Changes for required version) from
+http://oprofile.sourceforge.net/ and add ``idle=poll`` to the kernel command
+line.
+
+Configure with ``CONFIG_PROFILING=y`` and ``CONFIG_OPROFILE=y`` & reboot on new kernel::
+
+ ./configure --with-kernel-support
+ make install
+
+For superior results, be sure to enable the local APIC. If opreport sees
+a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
+penalty.
+
+One time setup::
+
+ opcontrol --setup --vmlinux=/boot/vmlinux
+
+Some ``opcontrol`` commands::
+
+ clear opcontrol --reset
+ start opcontrol --start
+ <test>
+ stop opcontrol --stop
+ dump output opreport > output_file
+
+To only report on the kernel, run ``opreport -l /boot/vmlinux > output_file``
+
+A reset is needed to clear old statistics, which survive a reboot.
--- /dev/null
+Kernel Support for miscellaneous (your favourite) Binary Formats v1.1
+=====================================================================
+
+This Kernel feature allows you to invoke almost (for restrictions see below)
+every program by simply typing its name in the shell.
+This includes for example compiled Java(TM), Python or Emacs programs.
+
+To achieve this you must tell binfmt_misc which interpreter has to be invoked
+with which binary. Binfmt_misc recognises the binary-type by matching some bytes
+at the beginning of the file with a magic byte sequence (masking out specified
+bits) you have supplied. Binfmt_misc can also recognise a filename extension
+aka ``.com`` or ``.exe``.
+
+First you must mount binfmt_misc::
+
+ mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
+
+To actually register a new binary type, you have to set up a string looking like
+``:name:type:offset:magic:mask:interpreter:flags`` (where you can choose the
+``:`` upon your needs) and echo it to ``/proc/sys/fs/binfmt_misc/register``.
+
+Here is what the fields mean:
+
+- ``name``
+ is an identifier string. A new /proc file will be created with this
+ ``name below /proc/sys/fs/binfmt_misc``; cannot contain slashes ``/`` for
+ obvious reasons.
+- ``type``
+ is the type of recognition. Give ``M`` for magic and ``E`` for extension.
+- ``offset``
+ is the offset of the magic/mask in the file, counted in bytes. This
+ defaults to 0 if you omit it (i.e. you write ``:name:type::magic...``).
+ Ignored when using filename extension matching.
+- ``magic``
+ is the byte sequence binfmt_misc is matching for. The magic string
+ may contain hex-encoded characters like ``\x0a`` or ``\xA4``. Note that you
+ must escape any NUL bytes; parsing halts at the first one. In a shell
+ environment you might have to write ``\\x0a`` to prevent the shell from
+ eating your ``\``.
+ If you chose filename extension matching, this is the extension to be
+ recognised (without the ``.``, the ``\x0a`` specials are not allowed).
+ Extension matching is case sensitive, and slashes ``/`` are not allowed!
+- ``mask``
+ is an (optional, defaults to all 0xff) mask. You can mask out some
+ bits from matching by supplying a string like magic and as long as magic.
+ The mask is anded with the byte sequence of the file. Note that you must
+ escape any NUL bytes; parsing halts at the first one. Ignored when using
+ filename extension matching.
+- ``interpreter``
+ is the program that should be invoked with the binary as first
+ argument (specify the full path)
+- ``flags``
+ is an optional field that controls several aspects of the invocation
+ of the interpreter. It is a string of capital letters, each controls a
+ certain aspect. The following flags are supported:
+
+ ``P`` - preserve-argv[0]
+ Legacy behavior of binfmt_misc is to overwrite
+ the original argv[0] with the full path to the binary. When this
+ flag is included, binfmt_misc will add an argument to the argument
+ vector for this purpose, thus preserving the original ``argv[0]``.
+ e.g. If your interp is set to ``/bin/foo`` and you run ``blah``
+ (which is in ``/usr/local/bin``), then the kernel will execute
+ ``/bin/foo`` with ``argv[]`` set to ``["/bin/foo", "/usr/local/bin/blah", "blah"]``. The interp has to be aware of this so it can
+ execute ``/usr/local/bin/blah``
+ with ``argv[]`` set to ``["blah"]``.
+ ``O`` - open-binary
+ Legacy behavior of binfmt_misc is to pass the full path
+ of the binary to the interpreter as an argument. When this flag is
+ included, binfmt_misc will open the file for reading and pass its
+ descriptor as an argument, instead of the full path, thus allowing
+ the interpreter to execute non-readable binaries. This feature
+ should be used with care - the interpreter has to be trusted not to
+ emit the contents of the non-readable binary.
+ ``C`` - credentials
+ Currently, the behavior of binfmt_misc is to calculate
+ the credentials and security token of the new process according to
+ the interpreter. When this flag is included, these attributes are
+ calculated according to the binary. It also implies the ``O`` flag.
+ This feature should be used with care as the interpreter
+ will run with root permissions when a setuid binary owned by root
+ is run with binfmt_misc.
+ ``F`` - fix binary
+ The usual behaviour of binfmt_misc is to spawn the
+ binary lazily when the misc format file is invoked. However,
+ this doesn``t work very well in the face of mount namespaces and
+ changeroots, so the ``F`` mode opens the binary as soon as the
+ emulation is installed and uses the opened image to spawn the
+ emulator, meaning it is always available once installed,
+ regardless of how the environment changes.
+
+
+There are some restrictions:
+
+ - the whole register string may not exceed 1920 characters
+ - the magic must reside in the first 128 bytes of the file, i.e.
+ offset+size(magic) has to be less than 128
+ - the interpreter string may not exceed 127 characters
+
+To use binfmt_misc you have to mount it first. You can mount it with
+``mount -t binfmt_misc none /proc/sys/fs/binfmt_misc`` command, or you can add
+a line ``none /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0`` to your
+``/etc/fstab`` so it auto mounts on boot.
+
+You may want to add the binary formats in one of your ``/etc/rc`` scripts during
+boot-up. Read the manual of your init program to figure out how to do this
+right.
+
+Think about the order of adding entries! Later added entries are matched first!
+
+
+A few examples (assumed you are in ``/proc/sys/fs/binfmt_misc``):
+
+- enable support for em86 (like binfmt_em86, for Alpha AXP only)::
+
+ echo ':i386:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register
+ echo ':i486:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register
+
+- enable support for packed DOS applications (pre-configured dosemu hdimages)::
+
+ echo ':DEXE:M::\x0eDEX::/usr/bin/dosexec:' > register
+
+- enable support for Windows executables using wine::
+
+ echo ':DOSWin:M::MZ::/usr/local/bin/wine:' > register
+
+For java support see Documentation/java.txt
+
+
+You can enable/disable binfmt_misc or one binary type by echoing 0 (to disable)
+or 1 (to enable) to ``/proc/sys/fs/binfmt_misc/status`` or
+``/proc/.../the_name``.
+Catting the file tells you the current status of ``binfmt_misc/the_entry``.
+
+You can remove one entry or all entries by echoing -1 to ``/proc/.../the_name``
+or ``/proc/sys/fs/binfmt_misc/status``.
+
+
+Hints
+-----
+
+If you want to pass special arguments to your interpreter, you can
+write a wrapper script for it. See Documentation/java.txt for an
+example.
+
+Your interpreter should NOT look in the PATH for the filename; the kernel
+passes it the full filename (or the file descriptor) to use. Using ``$PATH`` can
+cause unexpected behaviour and can be a security hazard.
+
+
+Richard Günther <rguenth@tat.physik.uni-tuebingen.de>
--- /dev/null
+Linux Braille Console
+=====================
+
+To get early boot messages on a braille device (before userspace screen
+readers can start), you first need to compile the support for the usual serial
+console (see :ref:`Documentation/serial-console.txt <serial_console>`), and
+for braille device
+(in :menuselection:`Device Drivers --> Accessibility support --> Console on braille device`).
+
+Then you need to specify a ``console=brl``, option on the kernel command line, the
+format is::
+
+ console=brl,serial_options...
+
+where ``serial_options...`` are the same as described in
+:ref:`Documentation/serial-console.txt <serial_console>`.
+
+So for instance you can use ``console=brl,ttyS0`` if the braille device is connected to the first serial port, and ``console=brl,ttyS0,115200`` to
+override the baud rate to 115200, etc.
+
+By default, the braille device will just show the last kernel message (console
+mode). To review previous messages, press the Insert key to switch to the VT
+review mode. In review mode, the arrow keys permit to browse in the VT content,
+:kbd:`PAGE-UP`/:kbd:`PAGE-DOWN` keys go at the top/bottom of the screen, and
+the :kbd:`HOME` key goes back
+to the cursor, hence providing very basic screen reviewing facility.
+
+Sound feedback can be obtained by adding the ``braille_console.sound=1`` kernel
+parameter.
+
+For simplicity, only one braille console can be enabled, other uses of
+``console=brl,...`` will be discarded. Also note that it does not interfere with
+the console selection mechanism described in
+:ref:`Documentation/serial-console.txt <serial_console>`.
+
+For now, only the VisioBraille device is supported.
+
+Samuel Thibault <samuel.thibault@ens-lyon.org>
--- /dev/null
+Bug hunting
++++++++++++
+
+Last updated: 20 December 2005
+
+Introduction
+============
+
+Always try the latest kernel from kernel.org and build from source. If you are
+not confident in doing that please report the bug to your distribution vendor
+instead of to a kernel developer.
+
+Finding bugs is not always easy. Have a go though. If you can't find it don't
+give up. Report as much as you have found to the relevant maintainer. See
+MAINTAINERS for who that is for the subsystem you have worked on.
+
+Before you submit a bug report read
+:ref:`Documentation/REPORTING-BUGS <reportingbugs>`.
+
+Devices not appearing
+=====================
+
+Often this is caused by udev. Check that first before blaming it on the
+kernel.
+
+Finding patch that caused a bug
+===============================
+
+
+
+Finding using ``git-bisect``
+----------------------------
+
+Using the provided tools with ``git`` makes finding bugs easy provided the bug
+is reproducible.
+
+Steps to do it:
+
+- start using git for the kernel source
+- read the man page for ``git-bisect``
+- have fun
+
+Finding it the old way
+----------------------
+
+[Sat Mar 2 10:32:33 PST 1996 KERNEL_BUG-HOWTO lm@sgi.com (Larry McVoy)]
+
+This is how to track down a bug if you know nothing about kernel hacking.
+It's a brute force approach but it works pretty well.
+
+You need:
+
+ - A reproducible bug - it has to happen predictably (sorry)
+ - All the kernel tar files from a revision that worked to the
+ revision that doesn't
+
+You will then do:
+
+ - Rebuild a revision that you believe works, install, and verify that.
+ - Do a binary search over the kernels to figure out which one
+ introduced the bug. I.e., suppose 1.3.28 didn't have the bug, but
+ you know that 1.3.69 does. Pick a kernel in the middle and build
+ that, like 1.3.50. Build & test; if it works, pick the mid point
+ between .50 and .69, else the mid point between .28 and .50.
+ - You'll narrow it down to the kernel that introduced the bug. You
+ can probably do better than this but it gets tricky.
+
+ - Narrow it down to a subdirectory
+
+ - Copy kernel that works into "test". Let's say that 3.62 works,
+ but 3.63 doesn't. So you diff -r those two kernels and come
+ up with a list of directories that changed. For each of those
+ directories:
+
+ Copy the non-working directory next to the working directory
+ as "dir.63".
+ One directory at time, try moving the working directory to
+ "dir.62" and mv dir.63 dir"time, try::
+
+ mv dir dir.62
+ mv dir.63 dir
+ find dir -name '*.[oa]' -print | xargs rm -f
+
+ And then rebuild and retest. Assuming that all related
+ changes were contained in the sub directory, this should
+ isolate the change to a directory.
+
+ Problems: changes in header files may have occurred; I've
+ found in my case that they were self explanatory - you may
+ or may not want to give up when that happens.
+
+ - Narrow it down to a file
+
+ - You can apply the same technique to each file in the directory,
+ hoping that the changes in that file are self contained.
+
+ - Narrow it down to a routine
+
+ - You can take the old file and the new file and manually create
+ a merged file that has::
+
+ #ifdef VER62
+ routine()
+ {
+ ...
+ }
+ #else
+ routine()
+ {
+ ...
+ }
+ #endif
+
+ And then walk through that file, one routine at a time and
+ prefix it with::
+
+ #define VER62
+ /* both routines here */
+ #undef VER62
+
+ Then recompile, retest, move the ifdefs until you find the one
+ that makes the difference.
+
+Finally, you take all the info that you have, kernel revisions, bug
+description, the extent to which you have narrowed it down, and pass
+that off to whomever you believe is the maintainer of that section.
+A post to linux.dev.kernel isn't such a bad idea if you've done some
+work to narrow it down.
+
+If you get it down to a routine, you'll probably get a fix in 24 hours.
+
+My apologies to Linus and the other kernel hackers for describing this
+brute force approach, it's hardly what a kernel hacker would do. However,
+it does work and it lets non-hackers help fix bugs. And it is cool
+because Linux snapshots will let you do this - something that you can't
+do with vendor supplied releases.
+
+Fixing the bug
+==============
+
+Nobody is going to tell you how to fix bugs. Seriously. You need to work it
+out. But below are some hints on how to use the tools.
+
+To debug a kernel, use objdump and look for the hex offset from the crash
+output to find the valid line of code/assembler. Without debug symbols, you
+will see the assembler code for the routine shown, but if your kernel has
+debug symbols the C code will also be available. (Debug symbols can be enabled
+in the kernel hacking menu of the menu configuration.) For example::
+
+ objdump -r -S -l --disassemble net/dccp/ipv4.o
+
+.. note::
+
+ You need to be at the top level of the kernel tree for this to pick up
+ your C files.
+
+If you don't have access to the code you can also debug on some crash dumps
+e.g. crash dump output as shown by Dave Miller::
+
+ EIP is at ip_queue_xmit+0x14/0x4c0
+ ...
+ Code: 44 24 04 e8 6f 05 00 00 e9 e8 fe ff ff 8d 76 00 8d bc 27 00 00
+ 00 00 55 57 56 53 81 ec bc 00 00 00 8b ac 24 d0 00 00 00 8b 5d 08
+ <8b> 83 3c 01 00 00 89 44 24 14 8b 45 28 85 c0 89 44 24 18 0f 85
+
+ Put the bytes into a "foo.s" file like this:
+
+ .text
+ .globl foo
+ foo:
+ .byte .... /* bytes from Code: part of OOPS dump */
+
+ Compile it with "gcc -c -o foo.o foo.s" then look at the output of
+ "objdump --disassemble foo.o".
+
+ Output:
+
+ ip_queue_xmit:
+ push %ebp
+ push %edi
+ push %esi
+ push %ebx
+ sub $0xbc, %esp
+ mov 0xd0(%esp), %ebp ! %ebp = arg0 (skb)
+ mov 0x8(%ebp), %ebx ! %ebx = skb->sk
+ mov 0x13c(%ebx), %eax ! %eax = inet_sk(sk)->opt
+
+In addition, you can use GDB to figure out the exact file and line
+number of the OOPS from the ``vmlinux`` file. If you have
+``CONFIG_DEBUG_INFO`` enabled, you can simply copy the EIP value from the
+OOPS::
+
+ EIP: 0060:[<c021e50e>] Not tainted VLI
+
+And use GDB to translate that to human-readable form::
+
+ gdb vmlinux
+ (gdb) l *0xc021e50e
+
+If you don't have ``CONFIG_DEBUG_INFO`` enabled, you use the function
+offset from the OOPS::
+
+ EIP is at vt_ioctl+0xda8/0x1482
+
+And recompile the kernel with ``CONFIG_DEBUG_INFO`` enabled::
+
+ make vmlinux
+ gdb vmlinux
+ (gdb) p vt_ioctl
+ (gdb) l *(0x<address of vt_ioctl> + 0xda8)
+
+or, as one command::
+
+ (gdb) l *(vt_ioctl + 0xda8)
+
+If you have a call trace, such as::
+
+ Call Trace:
+ [<ffffffff8802c8e9>] :jbd:log_wait_commit+0xa3/0xf5
+ [<ffffffff810482d9>] autoremove_wake_function+0x0/0x2e
+ [<ffffffff8802770b>] :jbd:journal_stop+0x1be/0x1ee
+ ...
+
+this shows the problem in the :jbd: module. You can load that module in gdb
+and list the relevant code::
+
+ gdb fs/jbd/jbd.ko
+ (gdb) p log_wait_commit
+ (gdb) l *(0x<address> + 0xa3)
+
+or::
+
+ (gdb) l *(log_wait_commit + 0xa3)
+
+
+Another very useful option of the Kernel Hacking section in menuconfig is
+Debug memory allocations. This will help you see whether data has been
+initialised and not set before use etc. To see the values that get assigned
+with this look at ``mm/slab.c`` and search for ``POISON_INUSE``. When using
+this an Oops will often show the poisoned data instead of zero which is the
+default.
+
+Once you have worked out a fix please submit it upstream. After all open
+source is about sharing what you do and don't you want to be recognised for
+your genius?
+
+Please do read :ref:`Documentation/SubmittingPatches <submittingpatches>`
+though to help your code get accepted.
--- /dev/null
+# -*- coding: utf-8; mode: python -*-
+
+project = 'Linux Kernel User Documentation'
+
+tags.add("subproject")
+
+latex_documents = [
+ ('index', 'linux-user.tex', 'Linux Kernel User Documentation',
+ 'The kernel development community', 'manual'),
+]
--- /dev/null
+
+Linux allocated devices (4.x+ version)
+======================================
+
+This list is the Linux Device List, the official registry of allocated
+device numbers and ``/dev`` directory nodes for the Linux operating
+system.
+
+The LaTeX version of this document is no longer maintained, nor is
+the document that used to reside at lanana.org. This version in the
+mainline Linux kernel is the master document. Updates shall be sent
+as patches to the kernel maintainers (see the
+:ref:`Documentation/SubmittingPatches <submittingpatches>` document).
+Specifically explore the sections titled "CHAR and MISC DRIVERS", and
+"BLOCK LAYER" in the MAINTAINERS file to find the right maintainers
+to involve for character and block devices.
+
+This document is included by reference into the Filesystem Hierarchy
+Standard (FHS). The FHS is available from http://www.pathname.com/fhs/.
+
+Allocations marked (68k/Amiga) apply to Linux/68k on the Amiga
+platform only. Allocations marked (68k/Atari) apply to Linux/68k on
+the Atari platform only.
+
+This document is in the public domain. The authors requests, however,
+that semantically altered versions are not distributed without
+permission of the authors, assuming the authors can be contacted without
+an unreasonable effort.
+
+
+.. attention::
+
+ DEVICE DRIVERS AUTHORS PLEASE READ THIS
+
+ Linux now has extensive support for dynamic allocation of device numbering
+ and can use ``sysfs`` and ``udev`` (``systemd``) to handle the naming needs.
+ There are still some exceptions in the serial and boot device area. Before
+ asking for a device number make sure you actually need one.
+
+ To have a major number allocated, or a minor number in situations
+ where that applies (e.g. busmice), please submit a patch and send to
+ the authors as indicated above.
+
+ Keep the description of the device *in the same format
+ as this list*. The reason for this is that it is the only way we have
+ found to ensure we have all the requisite information to publish your
+ device and avoid conflicts.
+
+ Finally, sometimes we have to play "namespace police." Please don't be
+ offended. We often get submissions for ``/dev`` names that would be bound
+ to cause conflicts down the road. We are trying to avoid getting in a
+ situation where we would have to suffer an incompatible forward
+ change. Therefore, please consult with us **before** you make your
+ device names and numbers in any way public, at least to the point
+ where it would be at all difficult to get them changed.
+
+ Your cooperation is appreciated.
+
+::
+
+ 0 Unnamed devices (e.g. non-device mounts)
+ 0 = reserved as null device number
+ See block major 144, 145, 146 for expansion areas.
+
+ 1 char Memory devices
+ 1 = /dev/mem Physical memory access
+ 2 = /dev/kmem Kernel virtual memory access
+ 3 = /dev/null Null device
+ 4 = /dev/port I/O port access
+ 5 = /dev/zero Null byte source
+ 6 = /dev/core OBSOLETE - replaced by /proc/kcore
+ 7 = /dev/full Returns ENOSPC on write
+ 8 = /dev/random Nondeterministic random number gen.
+ 9 = /dev/urandom Faster, less secure random number gen.
+ 10 = /dev/aio Asynchronous I/O notification interface
+ 11 = /dev/kmsg Writes to this come out as printk's, reads
+ export the buffered printk records.
+ 12 = /dev/oldmem OBSOLETE - replaced by /proc/vmcore
+
+ 1 block RAM disk
+ 0 = /dev/ram0 First RAM disk
+ 1 = /dev/ram1 Second RAM disk
+ ...
+ 250 = /dev/initrd Initial RAM disk
+
+ Older kernels had /dev/ramdisk (1, 1) here.
+ /dev/initrd refers to a RAM disk which was preloaded
+ by the boot loader; newer kernels use /dev/ram0 for
+ the initrd.
+
+ 2 char Pseudo-TTY masters
+ 0 = /dev/ptyp0 First PTY master
+ 1 = /dev/ptyp1 Second PTY master
+ ...
+ 255 = /dev/ptyef 256th PTY master
+
+ Pseudo-tty's are named as follows:
+ * Masters are "pty", slaves are "tty";
+ * the fourth letter is one of pqrstuvwxyzabcde indicating
+ the 1st through 16th series of 16 pseudo-ttys each, and
+ * the fifth letter is one of 0123456789abcdef indicating
+ the position within the series.
+
+ These are the old-style (BSD) PTY devices; Unix98
+ devices are on major 128 and above and use the PTY
+ master multiplex (/dev/ptmx) to acquire a PTY on
+ demand.
+
+ 2 block Floppy disks
+ 0 = /dev/fd0 Controller 0, drive 0, autodetect
+ 1 = /dev/fd1 Controller 0, drive 1, autodetect
+ 2 = /dev/fd2 Controller 0, drive 2, autodetect
+ 3 = /dev/fd3 Controller 0, drive 3, autodetect
+ 128 = /dev/fd4 Controller 1, drive 0, autodetect
+ 129 = /dev/fd5 Controller 1, drive 1, autodetect
+ 130 = /dev/fd6 Controller 1, drive 2, autodetect
+ 131 = /dev/fd7 Controller 1, drive 3, autodetect
+
+ To specify format, add to the autodetect device number:
+ 0 = /dev/fd? Autodetect format
+ 4 = /dev/fd?d360 5.25" 360K in a 360K drive(1)
+ 20 = /dev/fd?h360 5.25" 360K in a 1200K drive(1)
+ 48 = /dev/fd?h410 5.25" 410K in a 1200K drive
+ 64 = /dev/fd?h420 5.25" 420K in a 1200K drive
+ 24 = /dev/fd?h720 5.25" 720K in a 1200K drive
+ 80 = /dev/fd?h880 5.25" 880K in a 1200K drive(1)
+ 8 = /dev/fd?h1200 5.25" 1200K in a 1200K drive(1)
+ 40 = /dev/fd?h1440 5.25" 1440K in a 1200K drive(1)
+ 56 = /dev/fd?h1476 5.25" 1476K in a 1200K drive
+ 72 = /dev/fd?h1494 5.25" 1494K in a 1200K drive
+ 92 = /dev/fd?h1600 5.25" 1600K in a 1200K drive(1)
+
+ 12 = /dev/fd?u360 3.5" 360K Double Density(2)
+ 16 = /dev/fd?u720 3.5" 720K Double Density(1)
+ 120 = /dev/fd?u800 3.5" 800K Double Density(2)
+ 52 = /dev/fd?u820 3.5" 820K Double Density
+ 68 = /dev/fd?u830 3.5" 830K Double Density
+ 84 = /dev/fd?u1040 3.5" 1040K Double Density(1)
+ 88 = /dev/fd?u1120 3.5" 1120K Double Density(1)
+ 28 = /dev/fd?u1440 3.5" 1440K High Density(1)
+ 124 = /dev/fd?u1600 3.5" 1600K High Density(1)
+ 44 = /dev/fd?u1680 3.5" 1680K High Density(3)
+ 60 = /dev/fd?u1722 3.5" 1722K High Density
+ 76 = /dev/fd?u1743 3.5" 1743K High Density
+ 96 = /dev/fd?u1760 3.5" 1760K High Density
+ 116 = /dev/fd?u1840 3.5" 1840K High Density(3)
+ 100 = /dev/fd?u1920 3.5" 1920K High Density(1)
+ 32 = /dev/fd?u2880 3.5" 2880K Extra Density(1)
+ 104 = /dev/fd?u3200 3.5" 3200K Extra Density
+ 108 = /dev/fd?u3520 3.5" 3520K Extra Density
+ 112 = /dev/fd?u3840 3.5" 3840K Extra Density(1)
+
+ 36 = /dev/fd?CompaQ Compaq 2880K drive; obsolete?
+
+ (1) Autodetectable format
+ (2) Autodetectable format in a Double Density (720K) drive only
+ (3) Autodetectable format in a High Density (1440K) drive only
+
+ NOTE: The letter in the device name (d, q, h or u)
+ signifies the type of drive: 5.25" Double Density (d),
+ 5.25" Quad Density (q), 5.25" High Density (h) or 3.5"
+ (any model, u). The use of the capital letters D, H
+ and E for the 3.5" models have been deprecated, since
+ the drive type is insignificant for these devices.
+
+ 3 char Pseudo-TTY slaves
+ 0 = /dev/ttyp0 First PTY slave
+ 1 = /dev/ttyp1 Second PTY slave
+ ...
+ 255 = /dev/ttyef 256th PTY slave
+
+ These are the old-style (BSD) PTY devices; Unix98
+ devices are on major 136 and above.
+
+ 3 block First MFM, RLL and IDE hard disk/CD-ROM interface
+ 0 = /dev/hda Master: whole disk (or CD-ROM)
+ 64 = /dev/hdb Slave: whole disk (or CD-ROM)
+
+ For partitions, add to the whole disk device number:
+ 0 = /dev/hd? Whole disk
+ 1 = /dev/hd?1 First partition
+ 2 = /dev/hd?2 Second partition
+ ...
+ 63 = /dev/hd?63 63rd partition
+
+ For Linux/i386, partitions 1-4 are the primary
+ partitions, and 5 and above are logical partitions.
+ Other versions of Linux use partitioning schemes
+ appropriate to their respective architectures.
+
+ 4 char TTY devices
+ 0 = /dev/tty0 Current virtual console
+
+ 1 = /dev/tty1 First virtual console
+ ...
+ 63 = /dev/tty63 63rd virtual console
+ 64 = /dev/ttyS0 First UART serial port
+ ...
+ 255 = /dev/ttyS191 192nd UART serial port
+
+ UART serial ports refer to 8250/16450/16550 series devices.
+
+ Older versions of the Linux kernel used this major
+ number for BSD PTY devices. As of Linux 2.1.115, this
+ is no longer supported. Use major numbers 2 and 3.
+
+ 4 block Aliases for dynamically allocated major devices to be used
+ when its not possible to create the real device nodes
+ because the root filesystem is mounted read-only.
+
+ 0 = /dev/root
+
+ 5 char Alternate TTY devices
+ 0 = /dev/tty Current TTY device
+ 1 = /dev/console System console
+ 2 = /dev/ptmx PTY master multiplex
+ 3 = /dev/ttyprintk User messages via printk TTY device
+ 64 = /dev/cua0 Callout device for ttyS0
+ ...
+ 255 = /dev/cua191 Callout device for ttyS191
+
+ (5,1) is /dev/console starting with Linux 2.1.71. See
+ the section on terminal devices for more information
+ on /dev/console.
+
+ 6 char Parallel printer devices
+ 0 = /dev/lp0 Parallel printer on parport0
+ 1 = /dev/lp1 Parallel printer on parport1
+ ...
+
+ Current Linux kernels no longer have a fixed mapping
+ between parallel ports and I/O addresses. Instead,
+ they are redirected through the parport multiplex layer.
+
+ 7 char Virtual console capture devices
+ 0 = /dev/vcs Current vc text contents
+ 1 = /dev/vcs1 tty1 text contents
+ ...
+ 63 = /dev/vcs63 tty63 text contents
+ 128 = /dev/vcsa Current vc text/attribute contents
+ 129 = /dev/vcsa1 tty1 text/attribute contents
+ ...
+ 191 = /dev/vcsa63 tty63 text/attribute contents
+
+ NOTE: These devices permit both read and write access.
+
+ 7 block Loopback devices
+ 0 = /dev/loop0 First loop device
+ 1 = /dev/loop1 Second loop device
+ ...
+
+ The loop devices are used to mount filesystems not
+ associated with block devices. The binding to the
+ loop devices is handled by mount(8) or losetup(8).
+
+ 8 block SCSI disk devices (0-15)
+ 0 = /dev/sda First SCSI disk whole disk
+ 16 = /dev/sdb Second SCSI disk whole disk
+ 32 = /dev/sdc Third SCSI disk whole disk
+ ...
+ 240 = /dev/sdp Sixteenth SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 9 char SCSI tape devices
+ 0 = /dev/st0 First SCSI tape, mode 0
+ 1 = /dev/st1 Second SCSI tape, mode 0
+ ...
+ 32 = /dev/st0l First SCSI tape, mode 1
+ 33 = /dev/st1l Second SCSI tape, mode 1
+ ...
+ 64 = /dev/st0m First SCSI tape, mode 2
+ 65 = /dev/st1m Second SCSI tape, mode 2
+ ...
+ 96 = /dev/st0a First SCSI tape, mode 3
+ 97 = /dev/st1a Second SCSI tape, mode 3
+ ...
+ 128 = /dev/nst0 First SCSI tape, mode 0, no rewind
+ 129 = /dev/nst1 Second SCSI tape, mode 0, no rewind
+ ...
+ 160 = /dev/nst0l First SCSI tape, mode 1, no rewind
+ 161 = /dev/nst1l Second SCSI tape, mode 1, no rewind
+ ...
+ 192 = /dev/nst0m First SCSI tape, mode 2, no rewind
+ 193 = /dev/nst1m Second SCSI tape, mode 2, no rewind
+ ...
+ 224 = /dev/nst0a First SCSI tape, mode 3, no rewind
+ 225 = /dev/nst1a Second SCSI tape, mode 3, no rewind
+ ...
+
+ "No rewind" refers to the omission of the default
+ automatic rewind on device close. The MTREW or MTOFFL
+ ioctl()'s can be used to rewind the tape regardless of
+ the device used to access it.
+
+ 9 block Metadisk (RAID) devices
+ 0 = /dev/md0 First metadisk group
+ 1 = /dev/md1 Second metadisk group
+ ...
+
+ The metadisk driver is used to span a
+ filesystem across multiple physical disks.
+
+ 10 char Non-serial mice, misc features
+ 0 = /dev/logibm Logitech bus mouse
+ 1 = /dev/psaux PS/2-style mouse port
+ 2 = /dev/inportbm Microsoft Inport bus mouse
+ 3 = /dev/atibm ATI XL bus mouse
+ 4 = /dev/jbm J-mouse
+ 4 = /dev/amigamouse Amiga mouse (68k/Amiga)
+ 5 = /dev/atarimouse Atari mouse
+ 6 = /dev/sunmouse Sun mouse
+ 7 = /dev/amigamouse1 Second Amiga mouse
+ 8 = /dev/smouse Simple serial mouse driver
+ 9 = /dev/pc110pad IBM PC-110 digitizer pad
+ 10 = /dev/adbmouse Apple Desktop Bus mouse
+ 11 = /dev/vrtpanel Vr41xx embedded touch panel
+ 13 = /dev/vpcmouse Connectix Virtual PC Mouse
+ 14 = /dev/touchscreen/ucb1x00 UCB 1x00 touchscreen
+ 15 = /dev/touchscreen/mk712 MK712 touchscreen
+ 128 = /dev/beep Fancy beep device
+ 129 =
+ 130 = /dev/watchdog Watchdog timer port
+ 131 = /dev/temperature Machine internal temperature
+ 132 = /dev/hwtrap Hardware fault trap
+ 133 = /dev/exttrp External device trap
+ 134 = /dev/apm_bios Advanced Power Management BIOS
+ 135 = /dev/rtc Real Time Clock
+ 137 = /dev/vhci Bluetooth virtual HCI driver
+ 139 = /dev/openprom SPARC OpenBoot PROM
+ 140 = /dev/relay8 Berkshire Products Octal relay card
+ 141 = /dev/relay16 Berkshire Products ISO-16 relay card
+ 142 =
+ 143 = /dev/pciconf PCI configuration space
+ 144 = /dev/nvram Non-volatile configuration RAM
+ 145 = /dev/hfmodem Soundcard shortwave modem control
+ 146 = /dev/graphics Linux/SGI graphics device
+ 147 = /dev/opengl Linux/SGI OpenGL pipe
+ 148 = /dev/gfx Linux/SGI graphics effects device
+ 149 = /dev/input/mouse Linux/SGI Irix emulation mouse
+ 150 = /dev/input/keyboard Linux/SGI Irix emulation keyboard
+ 151 = /dev/led Front panel LEDs
+ 152 = /dev/kpoll Kernel Poll Driver
+ 153 = /dev/mergemem Memory merge device
+ 154 = /dev/pmu Macintosh PowerBook power manager
+ 155 = /dev/isictl MultiTech ISICom serial control
+ 156 = /dev/lcd Front panel LCD display
+ 157 = /dev/ac Applicom Intl Profibus card
+ 158 = /dev/nwbutton Netwinder external button
+ 159 = /dev/nwdebug Netwinder debug interface
+ 160 = /dev/nwflash Netwinder flash memory
+ 161 = /dev/userdma User-space DMA access
+ 162 = /dev/smbus System Management Bus
+ 163 = /dev/lik Logitech Internet Keyboard
+ 164 = /dev/ipmo Intel Intelligent Platform Management
+ 165 = /dev/vmmon VMware virtual machine monitor
+ 166 = /dev/i2o/ctl I2O configuration manager
+ 167 = /dev/specialix_sxctl Specialix serial control
+ 168 = /dev/tcldrv Technology Concepts serial control
+ 169 = /dev/specialix_rioctl Specialix RIO serial control
+ 170 = /dev/thinkpad/thinkpad IBM Thinkpad devices
+ 171 = /dev/srripc QNX4 API IPC manager
+ 172 = /dev/usemaclone Semaphore clone device
+ 173 = /dev/ipmikcs Intelligent Platform Management
+ 174 = /dev/uctrl SPARCbook 3 microcontroller
+ 175 = /dev/agpgart AGP Graphics Address Remapping Table
+ 176 = /dev/gtrsc Gorgy Timing radio clock
+ 177 = /dev/cbm Serial CBM bus
+ 178 = /dev/jsflash JavaStation OS flash SIMM
+ 179 = /dev/xsvc High-speed shared-mem/semaphore service
+ 180 = /dev/vrbuttons Vr41xx button input device
+ 181 = /dev/toshiba Toshiba laptop SMM support
+ 182 = /dev/perfctr Performance-monitoring counters
+ 183 = /dev/hwrng Generic random number generator
+ 184 = /dev/cpu/microcode CPU microcode update interface
+ 186 = /dev/atomicps Atomic shapshot of process state data
+ 187 = /dev/irnet IrNET device
+ 188 = /dev/smbusbios SMBus BIOS
+ 189 = /dev/ussp_ctl User space serial port control
+ 190 = /dev/crash Mission Critical Linux crash dump facility
+ 191 = /dev/pcl181 <information missing>
+ 192 = /dev/nas_xbus NAS xbus LCD/buttons access
+ 193 = /dev/d7s SPARC 7-segment display
+ 194 = /dev/zkshim Zero-Knowledge network shim control
+ 195 = /dev/elographics/e2201 Elographics touchscreen E271-2201
+ 196 = /dev/vfio/vfio VFIO userspace driver interface
+ 197 = /dev/pxa3xx-gcu PXA3xx graphics controller unit driver
+ 198 = /dev/sexec Signed executable interface
+ 199 = /dev/scanners/cuecat :CueCat barcode scanner
+ 200 = /dev/net/tun TAP/TUN network device
+ 201 = /dev/button/gulpb Transmeta GULP-B buttons
+ 202 = /dev/emd/ctl Enhanced Metadisk RAID (EMD) control
+ 203 = /dev/cuse Cuse (character device in user-space)
+ 204 = /dev/video/em8300 EM8300 DVD decoder control
+ 205 = /dev/video/em8300_mv EM8300 DVD decoder video
+ 206 = /dev/video/em8300_ma EM8300 DVD decoder audio
+ 207 = /dev/video/em8300_sp EM8300 DVD decoder subpicture
+ 208 = /dev/compaq/cpqphpc Compaq PCI Hot Plug Controller
+ 209 = /dev/compaq/cpqrid Compaq Remote Insight Driver
+ 210 = /dev/impi/bt IMPI coprocessor block transfer
+ 211 = /dev/impi/smic IMPI coprocessor stream interface
+ 212 = /dev/watchdogs/0 First watchdog device
+ 213 = /dev/watchdogs/1 Second watchdog device
+ 214 = /dev/watchdogs/2 Third watchdog device
+ 215 = /dev/watchdogs/3 Fourth watchdog device
+ 216 = /dev/fujitsu/apanel Fujitsu/Siemens application panel
+ 217 = /dev/ni/natmotn National Instruments Motion
+ 218 = /dev/kchuid Inter-process chuid control
+ 219 = /dev/modems/mwave MWave modem firmware upload
+ 220 = /dev/mptctl Message passing technology (MPT) control
+ 221 = /dev/mvista/hssdsi Montavista PICMG hot swap system driver
+ 222 = /dev/mvista/hasi Montavista PICMG high availability
+ 223 = /dev/input/uinput User level driver support for input
+ 224 = /dev/tpm TCPA TPM driver
+ 225 = /dev/pps Pulse Per Second driver
+ 226 = /dev/systrace Systrace device
+ 227 = /dev/mcelog X86_64 Machine Check Exception driver
+ 228 = /dev/hpet HPET driver
+ 229 = /dev/fuse Fuse (virtual filesystem in user-space)
+ 230 = /dev/midishare MidiShare driver
+ 231 = /dev/snapshot System memory snapshot device
+ 232 = /dev/kvm Kernel-based virtual machine (hardware virtualization extensions)
+ 233 = /dev/kmview View-OS A process with a view
+ 234 = /dev/btrfs-control Btrfs control device
+ 235 = /dev/autofs Autofs control device
+ 236 = /dev/mapper/control Device-Mapper control device
+ 237 = /dev/loop-control Loopback control device
+ 238 = /dev/vhost-net Host kernel accelerator for virtio net
+ 239 = /dev/uhid User-space I/O driver support for HID subsystem
+
+ 240-254 Reserved for local use
+ 255 Reserved for MISC_DYNAMIC_MINOR
+
+ 11 char Raw keyboard device (Linux/SPARC only)
+ 0 = /dev/kbd Raw keyboard device
+
+ 11 char Serial Mux device (Linux/PA-RISC only)
+ 0 = /dev/ttyB0 First mux port
+ 1 = /dev/ttyB1 Second mux port
+ ...
+
+ 11 block SCSI CD-ROM devices
+ 0 = /dev/scd0 First SCSI CD-ROM
+ 1 = /dev/scd1 Second SCSI CD-ROM
+ ...
+
+ The prefix /dev/sr (instead of /dev/scd) has been deprecated.
+
+ 12 char QIC-02 tape
+ 2 = /dev/ntpqic11 QIC-11, no rewind-on-close
+ 3 = /dev/tpqic11 QIC-11, rewind-on-close
+ 4 = /dev/ntpqic24 QIC-24, no rewind-on-close
+ 5 = /dev/tpqic24 QIC-24, rewind-on-close
+ 6 = /dev/ntpqic120 QIC-120, no rewind-on-close
+ 7 = /dev/tpqic120 QIC-120, rewind-on-close
+ 8 = /dev/ntpqic150 QIC-150, no rewind-on-close
+ 9 = /dev/tpqic150 QIC-150, rewind-on-close
+
+ The device names specified are proposed -- if there
+ are "standard" names for these devices, please let me know.
+
+ 12 block
+
+ 13 char Input core
+ 0 = /dev/input/js0 First joystick
+ 1 = /dev/input/js1 Second joystick
+ ...
+ 32 = /dev/input/mouse0 First mouse
+ 33 = /dev/input/mouse1 Second mouse
+ ...
+ 63 = /dev/input/mice Unified mouse
+ 64 = /dev/input/event0 First event queue
+ 65 = /dev/input/event1 Second event queue
+ ...
+
+ Each device type has 5 bits (32 minors).
+
+ 13 block Previously used for the XT disk (/dev/xdN)
+ Deleted in kernel v3.9.
+
+ 14 char Open Sound System (OSS)
+ 0 = /dev/mixer Mixer control
+ 1 = /dev/sequencer Audio sequencer
+ 2 = /dev/midi00 First MIDI port
+ 3 = /dev/dsp Digital audio
+ 4 = /dev/audio Sun-compatible digital audio
+ 6 =
+ 7 = /dev/audioctl SPARC audio control device
+ 8 = /dev/sequencer2 Sequencer -- alternate device
+ 16 = /dev/mixer1 Second soundcard mixer control
+ 17 = /dev/patmgr0 Sequencer patch manager
+ 18 = /dev/midi01 Second MIDI port
+ 19 = /dev/dsp1 Second soundcard digital audio
+ 20 = /dev/audio1 Second soundcard Sun digital audio
+ 33 = /dev/patmgr1 Sequencer patch manager
+ 34 = /dev/midi02 Third MIDI port
+ 50 = /dev/midi03 Fourth MIDI port
+
+ 14 block
+
+ 15 char Joystick
+ 0 = /dev/js0 First analog joystick
+ 1 = /dev/js1 Second analog joystick
+ ...
+ 128 = /dev/djs0 First digital joystick
+ 129 = /dev/djs1 Second digital joystick
+ ...
+ 15 block Sony CDU-31A/CDU-33A CD-ROM
+ 0 = /dev/sonycd Sony CDU-31a CD-ROM
+
+ 16 char Non-SCSI scanners
+ 0 = /dev/gs4500 Genius 4500 handheld scanner
+
+ 16 block GoldStar CD-ROM
+ 0 = /dev/gscd GoldStar CD-ROM
+
+ 17 char OBSOLETE (was Chase serial card)
+ 0 = /dev/ttyH0 First Chase port
+ 1 = /dev/ttyH1 Second Chase port
+ ...
+ 17 block Optics Storage CD-ROM
+ 0 = /dev/optcd Optics Storage CD-ROM
+
+ 18 char OBSOLETE (was Chase serial card - alternate devices)
+ 0 = /dev/cuh0 Callout device for ttyH0
+ 1 = /dev/cuh1 Callout device for ttyH1
+ ...
+ 18 block Sanyo CD-ROM
+ 0 = /dev/sjcd Sanyo CD-ROM
+
+ 19 char Cyclades serial card
+ 0 = /dev/ttyC0 First Cyclades port
+ ...
+ 31 = /dev/ttyC31 32nd Cyclades port
+
+ 19 block "Double" compressed disk
+ 0 = /dev/double0 First compressed disk
+ ...
+ 7 = /dev/double7 Eighth compressed disk
+ 128 = /dev/cdouble0 Mirror of first compressed disk
+ ...
+ 135 = /dev/cdouble7 Mirror of eighth compressed disk
+
+ See the Double documentation for the meaning of the
+ mirror devices.
+
+ 20 char Cyclades serial card - alternate devices
+ 0 = /dev/cub0 Callout device for ttyC0
+ ...
+ 31 = /dev/cub31 Callout device for ttyC31
+
+ 20 block Hitachi CD-ROM (under development)
+ 0 = /dev/hitcd Hitachi CD-ROM
+
+ 21 char Generic SCSI access
+ 0 = /dev/sg0 First generic SCSI device
+ 1 = /dev/sg1 Second generic SCSI device
+ ...
+
+ Most distributions name these /dev/sga, /dev/sgb...;
+ this sets an unnecessary limit of 26 SCSI devices in
+ the system and is counter to standard Linux
+ device-naming practice.
+
+ 21 block Acorn MFM hard drive interface
+ 0 = /dev/mfma First MFM drive whole disk
+ 64 = /dev/mfmb Second MFM drive whole disk
+
+ This device is used on the ARM-based Acorn RiscPC.
+ Partitions are handled the same way as for IDE disks
+ (see major number 3).
+
+ 22 char Digiboard serial card
+ 0 = /dev/ttyD0 First Digiboard port
+ 1 = /dev/ttyD1 Second Digiboard port
+ ...
+ 22 block Second IDE hard disk/CD-ROM interface
+ 0 = /dev/hdc Master: whole disk (or CD-ROM)
+ 64 = /dev/hdd Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 23 char Digiboard serial card - alternate devices
+ 0 = /dev/cud0 Callout device for ttyD0
+ 1 = /dev/cud1 Callout device for ttyD1
+ ...
+ 23 block Mitsumi proprietary CD-ROM
+ 0 = /dev/mcd Mitsumi CD-ROM
+
+ 24 char Stallion serial card
+ 0 = /dev/ttyE0 Stallion port 0 card 0
+ 1 = /dev/ttyE1 Stallion port 1 card 0
+ ...
+ 64 = /dev/ttyE64 Stallion port 0 card 1
+ 65 = /dev/ttyE65 Stallion port 1 card 1
+ ...
+ 128 = /dev/ttyE128 Stallion port 0 card 2
+ 129 = /dev/ttyE129 Stallion port 1 card 2
+ ...
+ 192 = /dev/ttyE192 Stallion port 0 card 3
+ 193 = /dev/ttyE193 Stallion port 1 card 3
+ ...
+ 24 block Sony CDU-535 CD-ROM
+ 0 = /dev/cdu535 Sony CDU-535 CD-ROM
+
+ 25 char Stallion serial card - alternate devices
+ 0 = /dev/cue0 Callout device for ttyE0
+ 1 = /dev/cue1 Callout device for ttyE1
+ ...
+ 64 = /dev/cue64 Callout device for ttyE64
+ 65 = /dev/cue65 Callout device for ttyE65
+ ...
+ 128 = /dev/cue128 Callout device for ttyE128
+ 129 = /dev/cue129 Callout device for ttyE129
+ ...
+ 192 = /dev/cue192 Callout device for ttyE192
+ 193 = /dev/cue193 Callout device for ttyE193
+ ...
+ 25 block First Matsushita (Panasonic/SoundBlaster) CD-ROM
+ 0 = /dev/sbpcd0 Panasonic CD-ROM controller 0 unit 0
+ 1 = /dev/sbpcd1 Panasonic CD-ROM controller 0 unit 1
+ 2 = /dev/sbpcd2 Panasonic CD-ROM controller 0 unit 2
+ 3 = /dev/sbpcd3 Panasonic CD-ROM controller 0 unit 3
+
+ 26 char
+
+ 26 block Second Matsushita (Panasonic/SoundBlaster) CD-ROM
+ 0 = /dev/sbpcd4 Panasonic CD-ROM controller 1 unit 0
+ 1 = /dev/sbpcd5 Panasonic CD-ROM controller 1 unit 1
+ 2 = /dev/sbpcd6 Panasonic CD-ROM controller 1 unit 2
+ 3 = /dev/sbpcd7 Panasonic CD-ROM controller 1 unit 3
+
+ 27 char QIC-117 tape
+ 0 = /dev/qft0 Unit 0, rewind-on-close
+ 1 = /dev/qft1 Unit 1, rewind-on-close
+ 2 = /dev/qft2 Unit 2, rewind-on-close
+ 3 = /dev/qft3 Unit 3, rewind-on-close
+ 4 = /dev/nqft0 Unit 0, no rewind-on-close
+ 5 = /dev/nqft1 Unit 1, no rewind-on-close
+ 6 = /dev/nqft2 Unit 2, no rewind-on-close
+ 7 = /dev/nqft3 Unit 3, no rewind-on-close
+ 16 = /dev/zqft0 Unit 0, rewind-on-close, compression
+ 17 = /dev/zqft1 Unit 1, rewind-on-close, compression
+ 18 = /dev/zqft2 Unit 2, rewind-on-close, compression
+ 19 = /dev/zqft3 Unit 3, rewind-on-close, compression
+ 20 = /dev/nzqft0 Unit 0, no rewind-on-close, compression
+ 21 = /dev/nzqft1 Unit 1, no rewind-on-close, compression
+ 22 = /dev/nzqft2 Unit 2, no rewind-on-close, compression
+ 23 = /dev/nzqft3 Unit 3, no rewind-on-close, compression
+ 32 = /dev/rawqft0 Unit 0, rewind-on-close, no file marks
+ 33 = /dev/rawqft1 Unit 1, rewind-on-close, no file marks
+ 34 = /dev/rawqft2 Unit 2, rewind-on-close, no file marks
+ 35 = /dev/rawqft3 Unit 3, rewind-on-close, no file marks
+ 36 = /dev/nrawqft0 Unit 0, no rewind-on-close, no file marks
+ 37 = /dev/nrawqft1 Unit 1, no rewind-on-close, no file marks
+ 38 = /dev/nrawqft2 Unit 2, no rewind-on-close, no file marks
+ 39 = /dev/nrawqft3 Unit 3, no rewind-on-close, no file marks
+
+ 27 block Third Matsushita (Panasonic/SoundBlaster) CD-ROM
+ 0 = /dev/sbpcd8 Panasonic CD-ROM controller 2 unit 0
+ 1 = /dev/sbpcd9 Panasonic CD-ROM controller 2 unit 1
+ 2 = /dev/sbpcd10 Panasonic CD-ROM controller 2 unit 2
+ 3 = /dev/sbpcd11 Panasonic CD-ROM controller 2 unit 3
+
+ 28 char Stallion serial card - card programming
+ 0 = /dev/staliomem0 First Stallion card I/O memory
+ 1 = /dev/staliomem1 Second Stallion card I/O memory
+ 2 = /dev/staliomem2 Third Stallion card I/O memory
+ 3 = /dev/staliomem3 Fourth Stallion card I/O memory
+
+ 28 char Atari SLM ACSI laser printer (68k/Atari)
+ 0 = /dev/slm0 First SLM laser printer
+ 1 = /dev/slm1 Second SLM laser printer
+ ...
+ 28 block Fourth Matsushita (Panasonic/SoundBlaster) CD-ROM
+ 0 = /dev/sbpcd12 Panasonic CD-ROM controller 3 unit 0
+ 1 = /dev/sbpcd13 Panasonic CD-ROM controller 3 unit 1
+ 2 = /dev/sbpcd14 Panasonic CD-ROM controller 3 unit 2
+ 3 = /dev/sbpcd15 Panasonic CD-ROM controller 3 unit 3
+
+ 28 block ACSI disk (68k/Atari)
+ 0 = /dev/ada First ACSI disk whole disk
+ 16 = /dev/adb Second ACSI disk whole disk
+ 32 = /dev/adc Third ACSI disk whole disk
+ ...
+ 240 = /dev/adp 16th ACSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15, like SCSI.
+
+ 29 char Universal frame buffer
+ 0 = /dev/fb0 First frame buffer
+ 1 = /dev/fb1 Second frame buffer
+ ...
+ 31 = /dev/fb31 32nd frame buffer
+
+ 29 block Aztech/Orchid/Okano/Wearnes CD-ROM
+ 0 = /dev/aztcd Aztech CD-ROM
+
+ 30 char iBCS-2 compatibility devices
+ 0 = /dev/socksys Socket access
+ 1 = /dev/spx SVR3 local X interface
+ 32 = /dev/inet/ip Network access
+ 33 = /dev/inet/icmp
+ 34 = /dev/inet/ggp
+ 35 = /dev/inet/ipip
+ 36 = /dev/inet/tcp
+ 37 = /dev/inet/egp
+ 38 = /dev/inet/pup
+ 39 = /dev/inet/udp
+ 40 = /dev/inet/idp
+ 41 = /dev/inet/rawip
+
+ Additionally, iBCS-2 requires the following links:
+
+ /dev/ip -> /dev/inet/ip
+ /dev/icmp -> /dev/inet/icmp
+ /dev/ggp -> /dev/inet/ggp
+ /dev/ipip -> /dev/inet/ipip
+ /dev/tcp -> /dev/inet/tcp
+ /dev/egp -> /dev/inet/egp
+ /dev/pup -> /dev/inet/pup
+ /dev/udp -> /dev/inet/udp
+ /dev/idp -> /dev/inet/idp
+ /dev/rawip -> /dev/inet/rawip
+ /dev/inet/arp -> /dev/inet/udp
+ /dev/inet/rip -> /dev/inet/udp
+ /dev/nfsd -> /dev/socksys
+ /dev/X0R -> /dev/null (? apparently not required ?)
+
+ 30 block Philips LMS CM-205 CD-ROM
+ 0 = /dev/cm205cd Philips LMS CM-205 CD-ROM
+
+ /dev/lmscd is an older name for this device. This
+ driver does not work with the CM-205MS CD-ROM.
+
+ 31 char MPU-401 MIDI
+ 0 = /dev/mpu401data MPU-401 data port
+ 1 = /dev/mpu401stat MPU-401 status port
+
+ 31 block ROM/flash memory card
+ 0 = /dev/rom0 First ROM card (rw)
+ ...
+ 7 = /dev/rom7 Eighth ROM card (rw)
+ 8 = /dev/rrom0 First ROM card (ro)
+ ...
+ 15 = /dev/rrom7 Eighth ROM card (ro)
+ 16 = /dev/flash0 First flash memory card (rw)
+ ...
+ 23 = /dev/flash7 Eighth flash memory card (rw)
+ 24 = /dev/rflash0 First flash memory card (ro)
+ ...
+ 31 = /dev/rflash7 Eighth flash memory card (ro)
+
+ The read-write (rw) devices support back-caching
+ written data in RAM, as well as writing to flash RAM
+ devices. The read-only devices (ro) support reading
+ only.
+
+ 32 char Specialix serial card
+ 0 = /dev/ttyX0 First Specialix port
+ 1 = /dev/ttyX1 Second Specialix port
+ ...
+ 32 block Philips LMS CM-206 CD-ROM
+ 0 = /dev/cm206cd Philips LMS CM-206 CD-ROM
+
+ 33 char Specialix serial card - alternate devices
+ 0 = /dev/cux0 Callout device for ttyX0
+ 1 = /dev/cux1 Callout device for ttyX1
+ ...
+ 33 block Third IDE hard disk/CD-ROM interface
+ 0 = /dev/hde Master: whole disk (or CD-ROM)
+ 64 = /dev/hdf Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 34 char Z8530 HDLC driver
+ 0 = /dev/scc0 First Z8530, first port
+ 1 = /dev/scc1 First Z8530, second port
+ 2 = /dev/scc2 Second Z8530, first port
+ 3 = /dev/scc3 Second Z8530, second port
+ ...
+
+ In a previous version these devices were named
+ /dev/sc1 for /dev/scc0, /dev/sc2 for /dev/scc1, and so
+ on.
+
+ 34 block Fourth IDE hard disk/CD-ROM interface
+ 0 = /dev/hdg Master: whole disk (or CD-ROM)
+ 64 = /dev/hdh Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 35 char tclmidi MIDI driver
+ 0 = /dev/midi0 First MIDI port, kernel timed
+ 1 = /dev/midi1 Second MIDI port, kernel timed
+ 2 = /dev/midi2 Third MIDI port, kernel timed
+ 3 = /dev/midi3 Fourth MIDI port, kernel timed
+ 64 = /dev/rmidi0 First MIDI port, untimed
+ 65 = /dev/rmidi1 Second MIDI port, untimed
+ 66 = /dev/rmidi2 Third MIDI port, untimed
+ 67 = /dev/rmidi3 Fourth MIDI port, untimed
+ 128 = /dev/smpte0 First MIDI port, SMPTE timed
+ 129 = /dev/smpte1 Second MIDI port, SMPTE timed
+ 130 = /dev/smpte2 Third MIDI port, SMPTE timed
+ 131 = /dev/smpte3 Fourth MIDI port, SMPTE timed
+
+ 35 block Slow memory ramdisk
+ 0 = /dev/slram Slow memory ramdisk
+
+ 36 char Netlink support
+ 0 = /dev/route Routing, device updates, kernel to user
+ 1 = /dev/skip enSKIP security cache control
+ 3 = /dev/fwmonitor Firewall packet copies
+ 16 = /dev/tap0 First Ethertap device
+ ...
+ 31 = /dev/tap15 16th Ethertap device
+
+ 36 block OBSOLETE (was MCA ESDI hard disk)
+
+ 37 char IDE tape
+ 0 = /dev/ht0 First IDE tape
+ 1 = /dev/ht1 Second IDE tape
+ ...
+ 128 = /dev/nht0 First IDE tape, no rewind-on-close
+ 129 = /dev/nht1 Second IDE tape, no rewind-on-close
+ ...
+
+ Currently, only one IDE tape drive is supported.
+
+ 37 block Zorro II ramdisk
+ 0 = /dev/z2ram Zorro II ramdisk
+
+ 38 char Myricom PCI Myrinet board
+ 0 = /dev/mlanai0 First Myrinet board
+ 1 = /dev/mlanai1 Second Myrinet board
+ ...
+
+ This device is used for status query, board control
+ and "user level packet I/O." This board is also
+ accessible as a standard networking "eth" device.
+
+ 38 block OBSOLETE (was Linux/AP+)
+
+ 39 char ML-16P experimental I/O board
+ 0 = /dev/ml16pa-a0 First card, first analog channel
+ 1 = /dev/ml16pa-a1 First card, second analog channel
+ ...
+ 15 = /dev/ml16pa-a15 First card, 16th analog channel
+ 16 = /dev/ml16pa-d First card, digital lines
+ 17 = /dev/ml16pa-c0 First card, first counter/timer
+ 18 = /dev/ml16pa-c1 First card, second counter/timer
+ 19 = /dev/ml16pa-c2 First card, third counter/timer
+ 32 = /dev/ml16pb-a0 Second card, first analog channel
+ 33 = /dev/ml16pb-a1 Second card, second analog channel
+ ...
+ 47 = /dev/ml16pb-a15 Second card, 16th analog channel
+ 48 = /dev/ml16pb-d Second card, digital lines
+ 49 = /dev/ml16pb-c0 Second card, first counter/timer
+ 50 = /dev/ml16pb-c1 Second card, second counter/timer
+ 51 = /dev/ml16pb-c2 Second card, third counter/timer
+ ...
+ 39 block
+
+ 40 char
+
+ 40 block
+
+ 41 char Yet Another Micro Monitor
+ 0 = /dev/yamm Yet Another Micro Monitor
+
+ 41 block
+
+ 42 char Demo/sample use
+
+ 42 block Demo/sample use
+
+ This number is intended for use in sample code, as
+ well as a general "example" device number. It
+ should never be used for a device driver that is being
+ distributed; either obtain an official number or use
+ the local/experimental range. The sudden addition or
+ removal of a driver with this number should not cause
+ ill effects to the system (bugs excepted.)
+
+ IN PARTICULAR, ANY DISTRIBUTION WHICH CONTAINS A
+ DEVICE DRIVER USING MAJOR NUMBER 42 IS NONCOMPLIANT.
+
+ 43 char isdn4linux virtual modem
+ 0 = /dev/ttyI0 First virtual modem
+ ...
+ 63 = /dev/ttyI63 64th virtual modem
+
+ 43 block Network block devices
+ 0 = /dev/nb0 First network block device
+ 1 = /dev/nb1 Second network block device
+ ...
+
+ Network Block Device is somehow similar to loopback
+ devices: If you read from it, it sends packet across
+ network asking server for data. If you write to it, it
+ sends packet telling server to write. It could be used
+ to mounting filesystems over the net, swapping over
+ the net, implementing block device in userland etc.
+
+ 44 char isdn4linux virtual modem - alternate devices
+ 0 = /dev/cui0 Callout device for ttyI0
+ ...
+ 63 = /dev/cui63 Callout device for ttyI63
+
+ 44 block Flash Translation Layer (FTL) filesystems
+ 0 = /dev/ftla FTL on first Memory Technology Device
+ 16 = /dev/ftlb FTL on second Memory Technology Device
+ 32 = /dev/ftlc FTL on third Memory Technology Device
+ ...
+ 240 = /dev/ftlp FTL on 16th Memory Technology Device
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the partition
+ limit is 15 rather than 63 per disk (same as SCSI.)
+
+ 45 char isdn4linux ISDN BRI driver
+ 0 = /dev/isdn0 First virtual B channel raw data
+ ...
+ 63 = /dev/isdn63 64th virtual B channel raw data
+ 64 = /dev/isdnctrl0 First channel control/debug
+ ...
+ 127 = /dev/isdnctrl63 64th channel control/debug
+
+ 128 = /dev/ippp0 First SyncPPP device
+ ...
+ 191 = /dev/ippp63 64th SyncPPP device
+
+ 255 = /dev/isdninfo ISDN monitor interface
+
+ 45 block Parallel port IDE disk devices
+ 0 = /dev/pda First parallel port IDE disk
+ 16 = /dev/pdb Second parallel port IDE disk
+ 32 = /dev/pdc Third parallel port IDE disk
+ 48 = /dev/pdd Fourth parallel port IDE disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the partition
+ limit is 15 rather than 63 per disk.
+
+ 46 char Comtrol Rocketport serial card
+ 0 = /dev/ttyR0 First Rocketport port
+ 1 = /dev/ttyR1 Second Rocketport port
+ ...
+ 46 block Parallel port ATAPI CD-ROM devices
+ 0 = /dev/pcd0 First parallel port ATAPI CD-ROM
+ 1 = /dev/pcd1 Second parallel port ATAPI CD-ROM
+ 2 = /dev/pcd2 Third parallel port ATAPI CD-ROM
+ 3 = /dev/pcd3 Fourth parallel port ATAPI CD-ROM
+
+ 47 char Comtrol Rocketport serial card - alternate devices
+ 0 = /dev/cur0 Callout device for ttyR0
+ 1 = /dev/cur1 Callout device for ttyR1
+ ...
+ 47 block Parallel port ATAPI disk devices
+ 0 = /dev/pf0 First parallel port ATAPI disk
+ 1 = /dev/pf1 Second parallel port ATAPI disk
+ 2 = /dev/pf2 Third parallel port ATAPI disk
+ 3 = /dev/pf3 Fourth parallel port ATAPI disk
+
+ This driver is intended for floppy disks and similar
+ devices and hence does not support partitioning.
+
+ 48 char SDL RISCom serial card
+ 0 = /dev/ttyL0 First RISCom port
+ 1 = /dev/ttyL1 Second RISCom port
+ ...
+ 48 block Mylex DAC960 PCI RAID controller; first controller
+ 0 = /dev/rd/c0d0 First disk, whole disk
+ 8 = /dev/rd/c0d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c0d31 32nd disk, whole disk
+
+ For partitions add:
+ 0 = /dev/rd/c?d? Whole disk
+ 1 = /dev/rd/c?d?p1 First partition
+ ...
+ 7 = /dev/rd/c?d?p7 Seventh partition
+
+ 49 char SDL RISCom serial card - alternate devices
+ 0 = /dev/cul0 Callout device for ttyL0
+ 1 = /dev/cul1 Callout device for ttyL1
+ ...
+ 49 block Mylex DAC960 PCI RAID controller; second controller
+ 0 = /dev/rd/c1d0 First disk, whole disk
+ 8 = /dev/rd/c1d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c1d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 50 char Reserved for GLINT
+
+ 50 block Mylex DAC960 PCI RAID controller; third controller
+ 0 = /dev/rd/c2d0 First disk, whole disk
+ 8 = /dev/rd/c2d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c2d31 32nd disk, whole disk
+
+ 51 char Baycom radio modem OR Radio Tech BIM-XXX-RS232 radio modem
+ 0 = /dev/bc0 First Baycom radio modem
+ 1 = /dev/bc1 Second Baycom radio modem
+ ...
+ 51 block Mylex DAC960 PCI RAID controller; fourth controller
+ 0 = /dev/rd/c3d0 First disk, whole disk
+ 8 = /dev/rd/c3d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c3d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 52 char Spellcaster DataComm/BRI ISDN card
+ 0 = /dev/dcbri0 First DataComm card
+ 1 = /dev/dcbri1 Second DataComm card
+ 2 = /dev/dcbri2 Third DataComm card
+ 3 = /dev/dcbri3 Fourth DataComm card
+
+ 52 block Mylex DAC960 PCI RAID controller; fifth controller
+ 0 = /dev/rd/c4d0 First disk, whole disk
+ 8 = /dev/rd/c4d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c4d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 53 char BDM interface for remote debugging MC683xx microcontrollers
+ 0 = /dev/pd_bdm0 PD BDM interface on lp0
+ 1 = /dev/pd_bdm1 PD BDM interface on lp1
+ 2 = /dev/pd_bdm2 PD BDM interface on lp2
+ 4 = /dev/icd_bdm0 ICD BDM interface on lp0
+ 5 = /dev/icd_bdm1 ICD BDM interface on lp1
+ 6 = /dev/icd_bdm2 ICD BDM interface on lp2
+
+ This device is used for the interfacing to the MC683xx
+ microcontrollers via Background Debug Mode by use of a
+ Parallel Port interface. PD is the Motorola Public
+ Domain Interface and ICD is the commercial interface
+ by P&E.
+
+ 53 block Mylex DAC960 PCI RAID controller; sixth controller
+ 0 = /dev/rd/c5d0 First disk, whole disk
+ 8 = /dev/rd/c5d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c5d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 54 char Electrocardiognosis Holter serial card
+ 0 = /dev/holter0 First Holter port
+ 1 = /dev/holter1 Second Holter port
+ 2 = /dev/holter2 Third Holter port
+
+ A custom serial card used by Electrocardiognosis SRL
+ <mseritan@ottonel.pub.ro> to transfer data from Holter
+ 24-hour heart monitoring equipment.
+
+ 54 block Mylex DAC960 PCI RAID controller; seventh controller
+ 0 = /dev/rd/c6d0 First disk, whole disk
+ 8 = /dev/rd/c6d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c6d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 55 char DSP56001 digital signal processor
+ 0 = /dev/dsp56k First DSP56001
+
+ 55 block Mylex DAC960 PCI RAID controller; eighth controller
+ 0 = /dev/rd/c7d0 First disk, whole disk
+ 8 = /dev/rd/c7d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c7d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 56 char Apple Desktop Bus
+ 0 = /dev/adb ADB bus control
+
+ Additional devices will be added to this number, all
+ starting with /dev/adb.
+
+ 56 block Fifth IDE hard disk/CD-ROM interface
+ 0 = /dev/hdi Master: whole disk (or CD-ROM)
+ 64 = /dev/hdj Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 57 char Hayes ESP serial card
+ 0 = /dev/ttyP0 First ESP port
+ 1 = /dev/ttyP1 Second ESP port
+ ...
+
+ 57 block Sixth IDE hard disk/CD-ROM interface
+ 0 = /dev/hdk Master: whole disk (or CD-ROM)
+ 64 = /dev/hdl Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 58 char Hayes ESP serial card - alternate devices
+ 0 = /dev/cup0 Callout device for ttyP0
+ 1 = /dev/cup1 Callout device for ttyP1
+ ...
+
+ 58 block Reserved for logical volume manager
+
+ 59 char sf firewall package
+ 0 = /dev/firewall Communication with sf kernel module
+
+ 59 block Generic PDA filesystem device
+ 0 = /dev/pda0 First PDA device
+ 1 = /dev/pda1 Second PDA device
+ ...
+
+ The pda devices are used to mount filesystems on
+ remote pda's (basically slow handheld machines with
+ proprietary OS's and limited memory and storage
+ running small fs translation drivers) through serial /
+ IRDA / parallel links.
+
+ NAMING CONFLICT -- PROPOSED REVISED NAME /dev/rpda0 etc
+
+ 60-63 char LOCAL/EXPERIMENTAL USE
+
+ 60-63 block LOCAL/EXPERIMENTAL USE
+ Allocated for local/experimental use. For devices not
+ assigned official numbers, these ranges should be
+ used in order to avoid conflicting with future assignments.
+
+ 64 char ENskip kernel encryption package
+ 0 = /dev/enskip Communication with ENskip kernel module
+
+ 64 block Scramdisk/DriveCrypt encrypted devices
+ 0 = /dev/scramdisk/master Master node for ioctls
+ 1 = /dev/scramdisk/1 First encrypted device
+ 2 = /dev/scramdisk/2 Second encrypted device
+ ...
+ 255 = /dev/scramdisk/255 255th encrypted device
+
+ The filename of the encrypted container and the passwords
+ are sent via ioctls (using the sdmount tool) to the master
+ node which then activates them via one of the
+ /dev/scramdisk/x nodes for loop mounting (all handled
+ through the sdmount tool).
+
+ Requested by: andy@scramdisklinux.org
+
+ 65 char Sundance "plink" Transputer boards (obsolete, unused)
+ 0 = /dev/plink0 First plink device
+ 1 = /dev/plink1 Second plink device
+ 2 = /dev/plink2 Third plink device
+ 3 = /dev/plink3 Fourth plink device
+ 64 = /dev/rplink0 First plink device, raw
+ 65 = /dev/rplink1 Second plink device, raw
+ 66 = /dev/rplink2 Third plink device, raw
+ 67 = /dev/rplink3 Fourth plink device, raw
+ 128 = /dev/plink0d First plink device, debug
+ 129 = /dev/plink1d Second plink device, debug
+ 130 = /dev/plink2d Third plink device, debug
+ 131 = /dev/plink3d Fourth plink device, debug
+ 192 = /dev/rplink0d First plink device, raw, debug
+ 193 = /dev/rplink1d Second plink device, raw, debug
+ 194 = /dev/rplink2d Third plink device, raw, debug
+ 195 = /dev/rplink3d Fourth plink device, raw, debug
+
+ This is a commercial driver; contact James Howes
+ <jth@prosig.demon.co.uk> for information.
+
+ 65 block SCSI disk devices (16-31)
+ 0 = /dev/sdq 17th SCSI disk whole disk
+ 16 = /dev/sdr 18th SCSI disk whole disk
+ 32 = /dev/sds 19th SCSI disk whole disk
+ ...
+ 240 = /dev/sdaf 32nd SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 66 char YARC PowerPC PCI coprocessor card
+ 0 = /dev/yppcpci0 First YARC card
+ 1 = /dev/yppcpci1 Second YARC card
+ ...
+
+ 66 block SCSI disk devices (32-47)
+ 0 = /dev/sdag 33th SCSI disk whole disk
+ 16 = /dev/sdah 34th SCSI disk whole disk
+ 32 = /dev/sdai 35th SCSI disk whole disk
+ ...
+ 240 = /dev/sdav 48nd SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 67 char Coda network file system
+ 0 = /dev/cfs0 Coda cache manager
+
+ See http://www.coda.cs.cmu.edu for information about Coda.
+
+ 67 block SCSI disk devices (48-63)
+ 0 = /dev/sdaw 49th SCSI disk whole disk
+ 16 = /dev/sdax 50th SCSI disk whole disk
+ 32 = /dev/sday 51st SCSI disk whole disk
+ ...
+ 240 = /dev/sdbl 64th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 68 char CAPI 2.0 interface
+ 0 = /dev/capi20 Control device
+ 1 = /dev/capi20.00 First CAPI 2.0 application
+ 2 = /dev/capi20.01 Second CAPI 2.0 application
+ ...
+ 20 = /dev/capi20.19 19th CAPI 2.0 application
+
+ ISDN CAPI 2.0 driver for use with CAPI 2.0
+ applications; currently supports the AVM B1 card.
+
+ 68 block SCSI disk devices (64-79)
+ 0 = /dev/sdbm 65th SCSI disk whole disk
+ 16 = /dev/sdbn 66th SCSI disk whole disk
+ 32 = /dev/sdbo 67th SCSI disk whole disk
+ ...
+ 240 = /dev/sdcb 80th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 69 char MA16 numeric accelerator card
+ 0 = /dev/ma16 Board memory access
+
+ 69 block SCSI disk devices (80-95)
+ 0 = /dev/sdcc 81st SCSI disk whole disk
+ 16 = /dev/sdcd 82nd SCSI disk whole disk
+ 32 = /dev/sdce 83th SCSI disk whole disk
+ ...
+ 240 = /dev/sdcr 96th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 70 char SpellCaster Protocol Services Interface
+ 0 = /dev/apscfg Configuration interface
+ 1 = /dev/apsauth Authentication interface
+ 2 = /dev/apslog Logging interface
+ 3 = /dev/apsdbg Debugging interface
+ 64 = /dev/apsisdn ISDN command interface
+ 65 = /dev/apsasync Async command interface
+ 128 = /dev/apsmon Monitor interface
+
+ 70 block SCSI disk devices (96-111)
+ 0 = /dev/sdcs 97th SCSI disk whole disk
+ 16 = /dev/sdct 98th SCSI disk whole disk
+ 32 = /dev/sdcu 99th SCSI disk whole disk
+ ...
+ 240 = /dev/sddh 112nd SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 71 char Computone IntelliPort II serial card
+ 0 = /dev/ttyF0 IntelliPort II board 0, port 0
+ 1 = /dev/ttyF1 IntelliPort II board 0, port 1
+ ...
+ 63 = /dev/ttyF63 IntelliPort II board 0, port 63
+ 64 = /dev/ttyF64 IntelliPort II board 1, port 0
+ 65 = /dev/ttyF65 IntelliPort II board 1, port 1
+ ...
+ 127 = /dev/ttyF127 IntelliPort II board 1, port 63
+ 128 = /dev/ttyF128 IntelliPort II board 2, port 0
+ 129 = /dev/ttyF129 IntelliPort II board 2, port 1
+ ...
+ 191 = /dev/ttyF191 IntelliPort II board 2, port 63
+ 192 = /dev/ttyF192 IntelliPort II board 3, port 0
+ 193 = /dev/ttyF193 IntelliPort II board 3, port 1
+ ...
+ 255 = /dev/ttyF255 IntelliPort II board 3, port 63
+
+ 71 block SCSI disk devices (112-127)
+ 0 = /dev/sddi 113th SCSI disk whole disk
+ 16 = /dev/sddj 114th SCSI disk whole disk
+ 32 = /dev/sddk 115th SCSI disk whole disk
+ ...
+ 240 = /dev/sddx 128th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 72 char Computone IntelliPort II serial card - alternate devices
+ 0 = /dev/cuf0 Callout device for ttyF0
+ 1 = /dev/cuf1 Callout device for ttyF1
+ ...
+ 63 = /dev/cuf63 Callout device for ttyF63
+ 64 = /dev/cuf64 Callout device for ttyF64
+ 65 = /dev/cuf65 Callout device for ttyF65
+ ...
+ 127 = /dev/cuf127 Callout device for ttyF127
+ 128 = /dev/cuf128 Callout device for ttyF128
+ 129 = /dev/cuf129 Callout device for ttyF129
+ ...
+ 191 = /dev/cuf191 Callout device for ttyF191
+ 192 = /dev/cuf192 Callout device for ttyF192
+ 193 = /dev/cuf193 Callout device for ttyF193
+ ...
+ 255 = /dev/cuf255 Callout device for ttyF255
+
+ 72 block Compaq Intelligent Drive Array, first controller
+ 0 = /dev/ida/c0d0 First logical drive whole disk
+ 16 = /dev/ida/c0d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c0d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 73 char Computone IntelliPort II serial card - control devices
+ 0 = /dev/ip2ipl0 Loadware device for board 0
+ 1 = /dev/ip2stat0 Status device for board 0
+ 4 = /dev/ip2ipl1 Loadware device for board 1
+ 5 = /dev/ip2stat1 Status device for board 1
+ 8 = /dev/ip2ipl2 Loadware device for board 2
+ 9 = /dev/ip2stat2 Status device for board 2
+ 12 = /dev/ip2ipl3 Loadware device for board 3
+ 13 = /dev/ip2stat3 Status device for board 3
+
+ 73 block Compaq Intelligent Drive Array, second controller
+ 0 = /dev/ida/c1d0 First logical drive whole disk
+ 16 = /dev/ida/c1d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c1d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 74 char SCI bridge
+ 0 = /dev/SCI/0 SCI device 0
+ 1 = /dev/SCI/1 SCI device 1
+ ...
+
+ Currently for Dolphin Interconnect Solutions' PCI-SCI
+ bridge.
+
+ 74 block Compaq Intelligent Drive Array, third controller
+ 0 = /dev/ida/c2d0 First logical drive whole disk
+ 16 = /dev/ida/c2d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c2d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 75 char Specialix IO8+ serial card
+ 0 = /dev/ttyW0 First IO8+ port, first card
+ 1 = /dev/ttyW1 Second IO8+ port, first card
+ ...
+ 8 = /dev/ttyW8 First IO8+ port, second card
+ ...
+
+ 75 block Compaq Intelligent Drive Array, fourth controller
+ 0 = /dev/ida/c3d0 First logical drive whole disk
+ 16 = /dev/ida/c3d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c3d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 76 char Specialix IO8+ serial card - alternate devices
+ 0 = /dev/cuw0 Callout device for ttyW0
+ 1 = /dev/cuw1 Callout device for ttyW1
+ ...
+ 8 = /dev/cuw8 Callout device for ttyW8
+ ...
+
+ 76 block Compaq Intelligent Drive Array, fifth controller
+ 0 = /dev/ida/c4d0 First logical drive whole disk
+ 16 = /dev/ida/c4d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c4d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+
+ 77 char ComScire Quantum Noise Generator
+ 0 = /dev/qng ComScire Quantum Noise Generator
+
+ 77 block Compaq Intelligent Drive Array, sixth controller
+ 0 = /dev/ida/c5d0 First logical drive whole disk
+ 16 = /dev/ida/c5d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c5d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 78 char PAM Software's multimodem boards
+ 0 = /dev/ttyM0 First PAM modem
+ 1 = /dev/ttyM1 Second PAM modem
+ ...
+
+ 78 block Compaq Intelligent Drive Array, seventh controller
+ 0 = /dev/ida/c6d0 First logical drive whole disk
+ 16 = /dev/ida/c6d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c6d15 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 79 char PAM Software's multimodem boards - alternate devices
+ 0 = /dev/cum0 Callout device for ttyM0
+ 1 = /dev/cum1 Callout device for ttyM1
+ ...
+
+ 79 block Compaq Intelligent Drive Array, eighth controller
+ 0 = /dev/ida/c7d0 First logical drive whole disk
+ 16 = /dev/ida/c7d1 Second logical drive whole disk
+ ...
+ 240 = /dev/ida/c715 16th logical drive whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 80 char Photometrics AT200 CCD camera
+ 0 = /dev/at200 Photometrics AT200 CCD camera
+
+ 80 block I2O hard disk
+ 0 = /dev/i2o/hda First I2O hard disk, whole disk
+ 16 = /dev/i2o/hdb Second I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdp 16th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 81 char video4linux
+ 0 = /dev/video0 Video capture/overlay device
+ ...
+ 63 = /dev/video63 Video capture/overlay device
+ 64 = /dev/radio0 Radio device
+ ...
+ 127 = /dev/radio63 Radio device
+ 128 = /dev/swradio0 Software Defined Radio device
+ ...
+ 191 = /dev/swradio63 Software Defined Radio device
+ 224 = /dev/vbi0 Vertical blank interrupt
+ ...
+ 255 = /dev/vbi31 Vertical blank interrupt
+
+ Minor numbers are allocated dynamically unless
+ CONFIG_VIDEO_FIXED_MINOR_RANGES (default n)
+ configuration option is set.
+
+ 81 block I2O hard disk
+ 0 = /dev/i2o/hdq 17th I2O hard disk, whole disk
+ 16 = /dev/i2o/hdr 18th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdaf 32nd I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 82 char WiNRADiO communications receiver card
+ 0 = /dev/winradio0 First WiNRADiO card
+ 1 = /dev/winradio1 Second WiNRADiO card
+ ...
+
+ The driver and documentation may be obtained from
+ http://www.winradio.com/
+
+ 82 block I2O hard disk
+ 0 = /dev/i2o/hdag 33rd I2O hard disk, whole disk
+ 16 = /dev/i2o/hdah 34th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdav 48th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 83 char Matrox mga_vid video driver
+ 0 = /dev/mga_vid0 1st video card
+ 1 = /dev/mga_vid1 2nd video card
+ 2 = /dev/mga_vid2 3rd video card
+ ...
+ 15 = /dev/mga_vid15 16th video card
+
+ 83 block I2O hard disk
+ 0 = /dev/i2o/hdaw 49th I2O hard disk, whole disk
+ 16 = /dev/i2o/hdax 50th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdbl 64th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 84 char Ikon 1011[57] Versatec Greensheet Interface
+ 0 = /dev/ihcp0 First Greensheet port
+ 1 = /dev/ihcp1 Second Greensheet port
+
+ 84 block I2O hard disk
+ 0 = /dev/i2o/hdbm 65th I2O hard disk, whole disk
+ 16 = /dev/i2o/hdbn 66th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdcb 80th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 85 char Linux/SGI shared memory input queue
+ 0 = /dev/shmiq Master shared input queue
+ 1 = /dev/qcntl0 First device pushed
+ 2 = /dev/qcntl1 Second device pushed
+ ...
+
+ 85 block I2O hard disk
+ 0 = /dev/i2o/hdcc 81st I2O hard disk, whole disk
+ 16 = /dev/i2o/hdcd 82nd I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hdcr 96th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 86 char SCSI media changer
+ 0 = /dev/sch0 First SCSI media changer
+ 1 = /dev/sch1 Second SCSI media changer
+ ...
+
+ 86 block I2O hard disk
+ 0 = /dev/i2o/hdcs 97th I2O hard disk, whole disk
+ 16 = /dev/i2o/hdct 98th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hddh 112th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 87 char Sony Control-A1 stereo control bus
+ 0 = /dev/controla0 First device on chain
+ 1 = /dev/controla1 Second device on chain
+ ...
+
+ 87 block I2O hard disk
+ 0 = /dev/i2o/hddi 113rd I2O hard disk, whole disk
+ 16 = /dev/i2o/hddj 114th I2O hard disk, whole disk
+ ...
+ 240 = /dev/i2o/hddx 128th I2O hard disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 88 char COMX synchronous serial card
+ 0 = /dev/comx0 COMX channel 0
+ 1 = /dev/comx1 COMX channel 1
+ ...
+
+ 88 block Seventh IDE hard disk/CD-ROM interface
+ 0 = /dev/hdm Master: whole disk (or CD-ROM)
+ 64 = /dev/hdn Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 89 char I2C bus interface
+ 0 = /dev/i2c-0 First I2C adapter
+ 1 = /dev/i2c-1 Second I2C adapter
+ ...
+
+ 89 block Eighth IDE hard disk/CD-ROM interface
+ 0 = /dev/hdo Master: whole disk (or CD-ROM)
+ 64 = /dev/hdp Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 90 char Memory Technology Device (RAM, ROM, Flash)
+ 0 = /dev/mtd0 First MTD (rw)
+ 1 = /dev/mtdr0 First MTD (ro)
+ ...
+ 30 = /dev/mtd15 16th MTD (rw)
+ 31 = /dev/mtdr15 16th MTD (ro)
+
+ 90 block Ninth IDE hard disk/CD-ROM interface
+ 0 = /dev/hdq Master: whole disk (or CD-ROM)
+ 64 = /dev/hdr Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 91 char CAN-Bus devices
+ 0 = /dev/can0 First CAN-Bus controller
+ 1 = /dev/can1 Second CAN-Bus controller
+ ...
+
+ 91 block Tenth IDE hard disk/CD-ROM interface
+ 0 = /dev/hds Master: whole disk (or CD-ROM)
+ 64 = /dev/hdt Slave: whole disk (or CD-ROM)
+
+ Partitions are handled the same way as for the first
+ interface (see major number 3).
+
+ 92 char Reserved for ith Kommunikationstechnik MIC ISDN card
+
+ 92 block PPDD encrypted disk driver
+ 0 = /dev/ppdd0 First encrypted disk
+ 1 = /dev/ppdd1 Second encrypted disk
+ ...
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 93 char
+
+ 93 block NAND Flash Translation Layer filesystem
+ 0 = /dev/nftla First NFTL layer
+ 16 = /dev/nftlb Second NFTL layer
+ ...
+ 240 = /dev/nftlp 16th NTFL layer
+
+ 94 char
+
+ 94 block IBM S/390 DASD block storage
+ 0 = /dev/dasda First DASD device, major
+ 1 = /dev/dasda1 First DASD device, block 1
+ 2 = /dev/dasda2 First DASD device, block 2
+ 3 = /dev/dasda3 First DASD device, block 3
+ 4 = /dev/dasdb Second DASD device, major
+ 5 = /dev/dasdb1 Second DASD device, block 1
+ 6 = /dev/dasdb2 Second DASD device, block 2
+ 7 = /dev/dasdb3 Second DASD device, block 3
+ ...
+
+ 95 char IP filter
+ 0 = /dev/ipl Filter control device/log file
+ 1 = /dev/ipnat NAT control device/log file
+ 2 = /dev/ipstate State information log file
+ 3 = /dev/ipauth Authentication control device/log file
+ ...
+
+ 96 char Parallel port ATAPI tape devices
+ 0 = /dev/pt0 First parallel port ATAPI tape
+ 1 = /dev/pt1 Second parallel port ATAPI tape
+ ...
+ 128 = /dev/npt0 First p.p. ATAPI tape, no rewind
+ 129 = /dev/npt1 Second p.p. ATAPI tape, no rewind
+ ...
+
+ 96 block Inverse NAND Flash Translation Layer
+ 0 = /dev/inftla First INFTL layer
+ 16 = /dev/inftlb Second INFTL layer
+ ...
+ 240 = /dev/inftlp 16th INTFL layer
+
+ 97 char Parallel port generic ATAPI interface
+ 0 = /dev/pg0 First parallel port ATAPI device
+ 1 = /dev/pg1 Second parallel port ATAPI device
+ 2 = /dev/pg2 Third parallel port ATAPI device
+ 3 = /dev/pg3 Fourth parallel port ATAPI device
+
+ These devices support the same API as the generic SCSI
+ devices.
+
+ 98 char Control and Measurement Device (comedi)
+ 0 = /dev/comedi0 First comedi device
+ 1 = /dev/comedi1 Second comedi device
+ ...
+
+ See http://stm.lbl.gov/comedi.
+
+ 98 block User-mode virtual block device
+ 0 = /dev/ubda First user-mode block device
+ 16 = /dev/udbb Second user-mode block device
+ ...
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ This device is used by the user-mode virtual kernel port.
+
+ 99 char Raw parallel ports
+ 0 = /dev/parport0 First parallel port
+ 1 = /dev/parport1 Second parallel port
+ ...
+
+ 99 block JavaStation flash disk
+ 0 = /dev/jsfd JavaStation flash disk
+
+ 100 char Telephony for Linux
+ 0 = /dev/phone0 First telephony device
+ 1 = /dev/phone1 Second telephony device
+ ...
+
+ 101 char Motorola DSP 56xxx board
+ 0 = /dev/mdspstat Status information
+ 1 = /dev/mdsp1 First DSP board I/O controls
+ ...
+ 16 = /dev/mdsp16 16th DSP board I/O controls
+
+ 101 block AMI HyperDisk RAID controller
+ 0 = /dev/amiraid/ar0 First array whole disk
+ 16 = /dev/amiraid/ar1 Second array whole disk
+ ...
+ 240 = /dev/amiraid/ar15 16th array whole disk
+
+ For each device, partitions are added as:
+ 0 = /dev/amiraid/ar? Whole disk
+ 1 = /dev/amiraid/ar?p1 First partition
+ 2 = /dev/amiraid/ar?p2 Second partition
+ ...
+ 15 = /dev/amiraid/ar?p15 15th partition
+
+ 102 char
+
+ 102 block Compressed block device
+ 0 = /dev/cbd/a First compressed block device, whole device
+ 16 = /dev/cbd/b Second compressed block device, whole device
+ ...
+ 240 = /dev/cbd/p 16th compressed block device, whole device
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 103 char Arla network file system
+ 0 = /dev/nnpfs0 First NNPFS device
+ 1 = /dev/nnpfs1 Second NNPFS device
+
+ Arla is a free clone of the Andrew File System, AFS.
+ The NNPFS device gives user mode filesystem
+ implementations a kernel presence for caching and easy
+ mounting. For more information about the project,
+ write to <arla-drinkers@stacken.kth.se> or see
+ http://www.stacken.kth.se/project/arla/
+
+ 103 block Audit device
+ 0 = /dev/audit Audit device
+
+ 104 char Flash BIOS support
+
+ 104 block Compaq Next Generation Drive Array, first controller
+ 0 = /dev/cciss/c0d0 First logical drive, whole disk
+ 16 = /dev/cciss/c0d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c0d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 105 char Comtrol VS-1000 serial controller
+ 0 = /dev/ttyV0 First VS-1000 port
+ 1 = /dev/ttyV1 Second VS-1000 port
+ ...
+
+ 105 block Compaq Next Generation Drive Array, second controller
+ 0 = /dev/cciss/c1d0 First logical drive, whole disk
+ 16 = /dev/cciss/c1d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c1d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 106 char Comtrol VS-1000 serial controller - alternate devices
+ 0 = /dev/cuv0 First VS-1000 port
+ 1 = /dev/cuv1 Second VS-1000 port
+ ...
+
+ 106 block Compaq Next Generation Drive Array, third controller
+ 0 = /dev/cciss/c2d0 First logical drive, whole disk
+ 16 = /dev/cciss/c2d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c2d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 107 char 3Dfx Voodoo Graphics device
+ 0 = /dev/3dfx Primary 3Dfx graphics device
+
+ 107 block Compaq Next Generation Drive Array, fourth controller
+ 0 = /dev/cciss/c3d0 First logical drive, whole disk
+ 16 = /dev/cciss/c3d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c3d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 108 char Device independent PPP interface
+ 0 = /dev/ppp Device independent PPP interface
+
+ 108 block Compaq Next Generation Drive Array, fifth controller
+ 0 = /dev/cciss/c4d0 First logical drive, whole disk
+ 16 = /dev/cciss/c4d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c4d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 109 char Reserved for logical volume manager
+
+ 109 block Compaq Next Generation Drive Array, sixth controller
+ 0 = /dev/cciss/c5d0 First logical drive, whole disk
+ 16 = /dev/cciss/c5d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c5d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 110 char miroMEDIA Surround board
+ 0 = /dev/srnd0 First miroMEDIA Surround board
+ 1 = /dev/srnd1 Second miroMEDIA Surround board
+ ...
+
+ 110 block Compaq Next Generation Drive Array, seventh controller
+ 0 = /dev/cciss/c6d0 First logical drive, whole disk
+ 16 = /dev/cciss/c6d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c6d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 111 char
+
+ 111 block Compaq Next Generation Drive Array, eighth controller
+ 0 = /dev/cciss/c7d0 First logical drive, whole disk
+ 16 = /dev/cciss/c7d1 Second logical drive, whole disk
+ ...
+ 240 = /dev/cciss/c7d15 16th logical drive, whole disk
+
+ Partitions are handled the same way as for Mylex
+ DAC960 (see major number 48) except that the limit on
+ partitions is 15.
+
+ 112 char ISI serial card
+ 0 = /dev/ttyM0 First ISI port
+ 1 = /dev/ttyM1 Second ISI port
+ ...
+
+ There is currently a device-naming conflict between
+ these and PAM multimodems (major 78).
+
+ 112 block IBM iSeries virtual disk
+ 0 = /dev/iseries/vda First virtual disk, whole disk
+ 8 = /dev/iseries/vdb Second virtual disk, whole disk
+ ...
+ 200 = /dev/iseries/vdz 26th virtual disk, whole disk
+ 208 = /dev/iseries/vdaa 27th virtual disk, whole disk
+ ...
+ 248 = /dev/iseries/vdaf 32nd virtual disk, whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 7.
+
+ 113 char ISI serial card - alternate devices
+ 0 = /dev/cum0 Callout device for ttyM0
+ 1 = /dev/cum1 Callout device for ttyM1
+ ...
+
+ 113 block IBM iSeries virtual CD-ROM
+ 0 = /dev/iseries/vcda First virtual CD-ROM
+ 1 = /dev/iseries/vcdb Second virtual CD-ROM
+ ...
+
+ 114 char Picture Elements ISE board
+ 0 = /dev/ise0 First ISE board
+ 1 = /dev/ise1 Second ISE board
+ ...
+ 128 = /dev/isex0 Control node for first ISE board
+ 129 = /dev/isex1 Control node for second ISE board
+ ...
+
+ The ISE board is an embedded computer, optimized for
+ image processing. The /dev/iseN nodes are the general
+ I/O access to the board, the /dev/isex0 nodes command
+ nodes used to control the board.
+
+ 114 block IDE BIOS powered software RAID interfaces such as the
+ Promise Fastrak
+
+ 0 = /dev/ataraid/d0
+ 1 = /dev/ataraid/d0p1
+ 2 = /dev/ataraid/d0p2
+ ...
+ 16 = /dev/ataraid/d1
+ 17 = /dev/ataraid/d1p1
+ 18 = /dev/ataraid/d1p2
+ ...
+ 255 = /dev/ataraid/d15p15
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 115 char TI link cable devices (115 was formerly the console driver speaker)
+ 0 = /dev/tipar0 Parallel cable on first parallel port
+ ...
+ 7 = /dev/tipar7 Parallel cable on seventh parallel port
+
+ 8 = /dev/tiser0 Serial cable on first serial port
+ ...
+ 15 = /dev/tiser7 Serial cable on seventh serial port
+
+ 16 = /dev/tiusb0 First USB cable
+ ...
+ 47 = /dev/tiusb31 32nd USB cable
+
+ 115 block NetWare (NWFS) Devices (0-255)
+
+ The NWFS (NetWare) devices are used to present a
+ collection of NetWare Mirror Groups or NetWare
+ Partitions as a logical storage segment for
+ use in mounting NetWare volumes. A maximum of
+ 256 NetWare volumes can be supported in a single
+ machine.
+
+ http://cgfa.telepac.pt/ftp2/kernel.org/linux/kernel/people/jmerkey/nwfs/
+
+ 0 = /dev/nwfs/v0 First NetWare (NWFS) Logical Volume
+ 1 = /dev/nwfs/v1 Second NetWare (NWFS) Logical Volume
+ 2 = /dev/nwfs/v2 Third NetWare (NWFS) Logical Volume
+ ...
+ 255 = /dev/nwfs/v255 Last NetWare (NWFS) Logical Volume
+
+ 116 char Advanced Linux Sound Driver (ALSA)
+
+ 116 block MicroMemory battery backed RAM adapter (NVRAM)
+ Supports 16 boards, 15 partitions each.
+ Requested by neilb at cse.unsw.edu.au.
+
+ 0 = /dev/umem/d0 Whole of first board
+ 1 = /dev/umem/d0p1 First partition of first board
+ 2 = /dev/umem/d0p2 Second partition of first board
+ 15 = /dev/umem/d0p15 15th partition of first board
+
+ 16 = /dev/umem/d1 Whole of second board
+ 17 = /dev/umem/d1p1 First partition of second board
+ ...
+ 255= /dev/umem/d15p15 15th partition of 16th board.
+
+ 117 char COSA/SRP synchronous serial card
+ 0 = /dev/cosa0c0 1st board, 1st channel
+ 1 = /dev/cosa0c1 1st board, 2nd channel
+ ...
+ 16 = /dev/cosa1c0 2nd board, 1st channel
+ 17 = /dev/cosa1c1 2nd board, 2nd channel
+ ...
+
+ 117 block Enterprise Volume Management System (EVMS)
+
+ The EVMS driver uses a layered, plug-in model to provide
+ unparalleled flexibility and extensibility in managing
+ storage. This allows for easy expansion or customization
+ of various levels of volume management. Requested by
+ Mark Peloquin (peloquin at us.ibm.com).
+
+ Note: EVMS populates and manages all the devnodes in
+ /dev/evms.
+
+ http://sf.net/projects/evms
+
+ 0 = /dev/evms/block_device EVMS block device
+ 1 = /dev/evms/legacyname1 First EVMS legacy device
+ 2 = /dev/evms/legacyname2 Second EVMS legacy device
+ ...
+ Both ranges can grow (down or up) until they meet.
+ ...
+ 254 = /dev/evms/EVMSname2 Second EVMS native device
+ 255 = /dev/evms/EVMSname1 First EVMS native device
+
+ Note: legacyname(s) are derived from the normal legacy
+ device names. For example, /dev/hda5 would become
+ /dev/evms/hda5.
+
+ 118 char IBM Cryptographic Accelerator
+ 0 = /dev/ica Virtual interface to all IBM Crypto Accelerators
+ 1 = /dev/ica0 IBMCA Device 0
+ 2 = /dev/ica1 IBMCA Device 1
+ ...
+
+ 119 char VMware virtual network control
+ 0 = /dev/vnet0 1st virtual network
+ 1 = /dev/vnet1 2nd virtual network
+ ...
+
+ 120-127 char LOCAL/EXPERIMENTAL USE
+
+ 120-127 block LOCAL/EXPERIMENTAL USE
+ Allocated for local/experimental use. For devices not
+ assigned official numbers, these ranges should be
+ used in order to avoid conflicting with future assignments.
+
+ 128-135 char Unix98 PTY masters
+
+ These devices should not have corresponding device
+ nodes; instead they should be accessed through the
+ /dev/ptmx cloning interface.
+
+ 128 block SCSI disk devices (128-143)
+ 0 = /dev/sddy 129th SCSI disk whole disk
+ 16 = /dev/sddz 130th SCSI disk whole disk
+ 32 = /dev/sdea 131th SCSI disk whole disk
+ ...
+ 240 = /dev/sden 144th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 129 block SCSI disk devices (144-159)
+ 0 = /dev/sdeo 145th SCSI disk whole disk
+ 16 = /dev/sdep 146th SCSI disk whole disk
+ 32 = /dev/sdeq 147th SCSI disk whole disk
+ ...
+ 240 = /dev/sdfd 160th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 130 char (Misc devices)
+
+ 130 block SCSI disk devices (160-175)
+ 0 = /dev/sdfe 161st SCSI disk whole disk
+ 16 = /dev/sdff 162nd SCSI disk whole disk
+ 32 = /dev/sdfg 163rd SCSI disk whole disk
+ ...
+ 240 = /dev/sdft 176th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 131 block SCSI disk devices (176-191)
+ 0 = /dev/sdfu 177th SCSI disk whole disk
+ 16 = /dev/sdfv 178th SCSI disk whole disk
+ 32 = /dev/sdfw 179th SCSI disk whole disk
+ ...
+ 240 = /dev/sdgj 192nd SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 132 block SCSI disk devices (192-207)
+ 0 = /dev/sdgk 193rd SCSI disk whole disk
+ 16 = /dev/sdgl 194th SCSI disk whole disk
+ 32 = /dev/sdgm 195th SCSI disk whole disk
+ ...
+ 240 = /dev/sdgz 208th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 133 block SCSI disk devices (208-223)
+ 0 = /dev/sdha 209th SCSI disk whole disk
+ 16 = /dev/sdhb 210th SCSI disk whole disk
+ 32 = /dev/sdhc 211th SCSI disk whole disk
+ ...
+ 240 = /dev/sdhp 224th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 134 block SCSI disk devices (224-239)
+ 0 = /dev/sdhq 225th SCSI disk whole disk
+ 16 = /dev/sdhr 226th SCSI disk whole disk
+ 32 = /dev/sdhs 227th SCSI disk whole disk
+ ...
+ 240 = /dev/sdif 240th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 135 block SCSI disk devices (240-255)
+ 0 = /dev/sdig 241st SCSI disk whole disk
+ 16 = /dev/sdih 242nd SCSI disk whole disk
+ 32 = /dev/sdih 243rd SCSI disk whole disk
+ ...
+ 240 = /dev/sdiv 256th SCSI disk whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 136-143 char Unix98 PTY slaves
+ 0 = /dev/pts/0 First Unix98 pseudo-TTY
+ 1 = /dev/pts/1 Second Unix98 pseudo-TTY
+ ...
+
+ These device nodes are automatically generated with
+ the proper permissions and modes by mounting the
+ devpts filesystem onto /dev/pts with the appropriate
+ mount options (distribution dependent, however, on
+ *most* distributions the appropriate options are
+ "mode=0620,gid=<gid of the "tty" group>".)
+
+ 136 block Mylex DAC960 PCI RAID controller; ninth controller
+ 0 = /dev/rd/c8d0 First disk, whole disk
+ 8 = /dev/rd/c8d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c8d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 137 block Mylex DAC960 PCI RAID controller; tenth controller
+ 0 = /dev/rd/c9d0 First disk, whole disk
+ 8 = /dev/rd/c9d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c9d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 138 block Mylex DAC960 PCI RAID controller; eleventh controller
+ 0 = /dev/rd/c10d0 First disk, whole disk
+ 8 = /dev/rd/c10d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c10d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 139 block Mylex DAC960 PCI RAID controller; twelfth controller
+ 0 = /dev/rd/c11d0 First disk, whole disk
+ 8 = /dev/rd/c11d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c11d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 140 block Mylex DAC960 PCI RAID controller; thirteenth controller
+ 0 = /dev/rd/c12d0 First disk, whole disk
+ 8 = /dev/rd/c12d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c12d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 141 block Mylex DAC960 PCI RAID controller; fourteenth controller
+ 0 = /dev/rd/c13d0 First disk, whole disk
+ 8 = /dev/rd/c13d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c13d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 142 block Mylex DAC960 PCI RAID controller; fifteenth controller
+ 0 = /dev/rd/c14d0 First disk, whole disk
+ 8 = /dev/rd/c14d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c14d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 143 block Mylex DAC960 PCI RAID controller; sixteenth controller
+ 0 = /dev/rd/c15d0 First disk, whole disk
+ 8 = /dev/rd/c15d1 Second disk, whole disk
+ ...
+ 248 = /dev/rd/c15d31 32nd disk, whole disk
+
+ Partitions are handled as for major 48.
+
+ 144 char Encapsulated PPP
+ 0 = /dev/pppox0 First PPP over Ethernet
+ ...
+ 63 = /dev/pppox63 64th PPP over Ethernet
+
+ This is primarily used for ADSL.
+
+ The SST 5136-DN DeviceNet interface driver has been
+ relocated to major 183 due to an unfortunate conflict.
+
+ 144 block Expansion Area #1 for more non-device (e.g. NFS) mounts
+ 0 = mounted device 256
+ 255 = mounted device 511
+
+ 145 char SAM9407-based soundcard
+ 0 = /dev/sam0_mixer
+ 1 = /dev/sam0_sequencer
+ 2 = /dev/sam0_midi00
+ 3 = /dev/sam0_dsp
+ 4 = /dev/sam0_audio
+ 6 = /dev/sam0_sndstat
+ 18 = /dev/sam0_midi01
+ 34 = /dev/sam0_midi02
+ 50 = /dev/sam0_midi03
+ 64 = /dev/sam1_mixer
+ ...
+ 128 = /dev/sam2_mixer
+ ...
+ 192 = /dev/sam3_mixer
+ ...
+
+ Device functions match OSS, but offer a number of
+ addons, which are sam9407 specific. OSS can be
+ operated simultaneously, taking care of the codec.
+
+ 145 block Expansion Area #2 for more non-device (e.g. NFS) mounts
+ 0 = mounted device 512
+ 255 = mounted device 767
+
+ 146 char SYSTRAM SCRAMNet mirrored-memory network
+ 0 = /dev/scramnet0 First SCRAMNet device
+ 1 = /dev/scramnet1 Second SCRAMNet device
+ ...
+
+ 146 block Expansion Area #3 for more non-device (e.g. NFS) mounts
+ 0 = mounted device 768
+ 255 = mounted device 1023
+
+ 147 char Aureal Semiconductor Vortex Audio device
+ 0 = /dev/aureal0 First Aureal Vortex
+ 1 = /dev/aureal1 Second Aureal Vortex
+ ...
+
+ 147 block Distributed Replicated Block Device (DRBD)
+ 0 = /dev/drbd0 First DRBD device
+ 1 = /dev/drbd1 Second DRBD device
+ ...
+
+ 148 char Technology Concepts serial card
+ 0 = /dev/ttyT0 First TCL port
+ 1 = /dev/ttyT1 Second TCL port
+ ...
+
+ 149 char Technology Concepts serial card - alternate devices
+ 0 = /dev/cut0 Callout device for ttyT0
+ 1 = /dev/cut0 Callout device for ttyT1
+ ...
+
+ 150 char Real-Time Linux FIFOs
+ 0 = /dev/rtf0 First RTLinux FIFO
+ 1 = /dev/rtf1 Second RTLinux FIFO
+ ...
+
+ 151 char DPT I2O SmartRaid V controller
+ 0 = /dev/dpti0 First DPT I2O adapter
+ 1 = /dev/dpti1 Second DPT I2O adapter
+ ...
+
+ 152 char EtherDrive Control Device
+ 0 = /dev/etherd/ctl Connect/Disconnect an EtherDrive
+ 1 = /dev/etherd/err Monitor errors
+ 2 = /dev/etherd/raw Raw AoE packet monitor
+
+ 152 block EtherDrive Block Devices
+ 0 = /dev/etherd/0 EtherDrive 0
+ ...
+ 255 = /dev/etherd/255 EtherDrive 255
+
+ 153 char SPI Bus Interface (sometimes referred to as MicroWire)
+ 0 = /dev/spi0 First SPI device on the bus
+ 1 = /dev/spi1 Second SPI device on the bus
+ ...
+ 15 = /dev/spi15 Sixteenth SPI device on the bus
+
+ 153 block Enhanced Metadisk RAID (EMD) storage units
+ 0 = /dev/emd/0 First unit
+ 1 = /dev/emd/0p1 Partition 1 on First unit
+ 2 = /dev/emd/0p2 Partition 2 on First unit
+ ...
+ 15 = /dev/emd/0p15 Partition 15 on First unit
+
+ 16 = /dev/emd/1 Second unit
+ 32 = /dev/emd/2 Third unit
+ ...
+ 240 = /dev/emd/15 Sixteenth unit
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 154 char Specialix RIO serial card
+ 0 = /dev/ttySR0 First RIO port
+ ...
+ 255 = /dev/ttySR255 256th RIO port
+
+ 155 char Specialix RIO serial card - alternate devices
+ 0 = /dev/cusr0 Callout device for ttySR0
+ ...
+ 255 = /dev/cusr255 Callout device for ttySR255
+
+ 156 char Specialix RIO serial card
+ 0 = /dev/ttySR256 257th RIO port
+ ...
+ 255 = /dev/ttySR511 512th RIO port
+
+ 157 char Specialix RIO serial card - alternate devices
+ 0 = /dev/cusr256 Callout device for ttySR256
+ ...
+ 255 = /dev/cusr511 Callout device for ttySR511
+
+ 158 char Dialogic GammaLink fax driver
+ 0 = /dev/gfax0 GammaLink channel 0
+ 1 = /dev/gfax1 GammaLink channel 1
+ ...
+
+ 159 char RESERVED
+
+ 159 block RESERVED
+
+ 160 char General Purpose Instrument Bus (GPIB)
+ 0 = /dev/gpib0 First GPIB bus
+ 1 = /dev/gpib1 Second GPIB bus
+ ...
+
+ 160 block Carmel 8-port SATA Disks on First Controller
+ 0 = /dev/carmel/0 SATA disk 0 whole disk
+ 1 = /dev/carmel/0p1 SATA disk 0 partition 1
+ ...
+ 31 = /dev/carmel/0p31 SATA disk 0 partition 31
+
+ 32 = /dev/carmel/1 SATA disk 1 whole disk
+ 64 = /dev/carmel/2 SATA disk 2 whole disk
+ ...
+ 224 = /dev/carmel/7 SATA disk 7 whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 31.
+
+ 161 char IrCOMM devices (IrDA serial/parallel emulation)
+ 0 = /dev/ircomm0 First IrCOMM device
+ 1 = /dev/ircomm1 Second IrCOMM device
+ ...
+ 16 = /dev/irlpt0 First IrLPT device
+ 17 = /dev/irlpt1 Second IrLPT device
+ ...
+
+ 161 block Carmel 8-port SATA Disks on Second Controller
+ 0 = /dev/carmel/8 SATA disk 8 whole disk
+ 1 = /dev/carmel/8p1 SATA disk 8 partition 1
+ ...
+ 31 = /dev/carmel/8p31 SATA disk 8 partition 31
+
+ 32 = /dev/carmel/9 SATA disk 9 whole disk
+ 64 = /dev/carmel/10 SATA disk 10 whole disk
+ ...
+ 224 = /dev/carmel/15 SATA disk 15 whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 31.
+
+ 162 char Raw block device interface
+ 0 = /dev/rawctl Raw I/O control device
+ 1 = /dev/raw/raw1 First raw I/O device
+ 2 = /dev/raw/raw2 Second raw I/O device
+ ...
+ max minor number of raw device is set by kernel config
+ MAX_RAW_DEVS or raw module parameter 'max_raw_devs'
+
+ 163 char
+
+ 164 char Chase Research AT/PCI-Fast serial card
+ 0 = /dev/ttyCH0 AT/PCI-Fast board 0, port 0
+ ...
+ 15 = /dev/ttyCH15 AT/PCI-Fast board 0, port 15
+ 16 = /dev/ttyCH16 AT/PCI-Fast board 1, port 0
+ ...
+ 31 = /dev/ttyCH31 AT/PCI-Fast board 1, port 15
+ 32 = /dev/ttyCH32 AT/PCI-Fast board 2, port 0
+ ...
+ 47 = /dev/ttyCH47 AT/PCI-Fast board 2, port 15
+ 48 = /dev/ttyCH48 AT/PCI-Fast board 3, port 0
+ ...
+ 63 = /dev/ttyCH63 AT/PCI-Fast board 3, port 15
+
+ 165 char Chase Research AT/PCI-Fast serial card - alternate devices
+ 0 = /dev/cuch0 Callout device for ttyCH0
+ ...
+ 63 = /dev/cuch63 Callout device for ttyCH63
+
+ 166 char ACM USB modems
+ 0 = /dev/ttyACM0 First ACM modem
+ 1 = /dev/ttyACM1 Second ACM modem
+ ...
+
+ 167 char ACM USB modems - alternate devices
+ 0 = /dev/cuacm0 Callout device for ttyACM0
+ 1 = /dev/cuacm1 Callout device for ttyACM1
+ ...
+
+ 168 char Eracom CSA7000 PCI encryption adaptor
+ 0 = /dev/ecsa0 First CSA7000
+ 1 = /dev/ecsa1 Second CSA7000
+ ...
+
+ 169 char Eracom CSA8000 PCI encryption adaptor
+ 0 = /dev/ecsa8-0 First CSA8000
+ 1 = /dev/ecsa8-1 Second CSA8000
+ ...
+
+ 170 char AMI MegaRAC remote access controller
+ 0 = /dev/megarac0 First MegaRAC card
+ 1 = /dev/megarac1 Second MegaRAC card
+ ...
+
+ 171 char Reserved for IEEE 1394 (Firewire)
+
+ 172 char Moxa Intellio serial card
+ 0 = /dev/ttyMX0 First Moxa port
+ 1 = /dev/ttyMX1 Second Moxa port
+ ...
+ 127 = /dev/ttyMX127 128th Moxa port
+ 128 = /dev/moxactl Moxa control port
+
+ 173 char Moxa Intellio serial card - alternate devices
+ 0 = /dev/cumx0 Callout device for ttyMX0
+ 1 = /dev/cumx1 Callout device for ttyMX1
+ ...
+ 127 = /dev/cumx127 Callout device for ttyMX127
+
+ 174 char SmartIO serial card
+ 0 = /dev/ttySI0 First SmartIO port
+ 1 = /dev/ttySI1 Second SmartIO port
+ ...
+
+ 175 char SmartIO serial card - alternate devices
+ 0 = /dev/cusi0 Callout device for ttySI0
+ 1 = /dev/cusi1 Callout device for ttySI1
+ ...
+
+ 176 char nCipher nFast PCI crypto accelerator
+ 0 = /dev/nfastpci0 First nFast PCI device
+ 1 = /dev/nfastpci1 First nFast PCI device
+ ...
+
+ 177 char TI PCILynx memory spaces
+ 0 = /dev/pcilynx/aux0 AUX space of first PCILynx card
+ ...
+ 15 = /dev/pcilynx/aux15 AUX space of 16th PCILynx card
+ 16 = /dev/pcilynx/rom0 ROM space of first PCILynx card
+ ...
+ 31 = /dev/pcilynx/rom15 ROM space of 16th PCILynx card
+ 32 = /dev/pcilynx/ram0 RAM space of first PCILynx card
+ ...
+ 47 = /dev/pcilynx/ram15 RAM space of 16th PCILynx card
+
+ 178 char Giganet cLAN1xxx virtual interface adapter
+ 0 = /dev/clanvi0 First cLAN adapter
+ 1 = /dev/clanvi1 Second cLAN adapter
+ ...
+
+ 179 block MMC block devices
+ 0 = /dev/mmcblk0 First SD/MMC card
+ 1 = /dev/mmcblk0p1 First partition on first MMC card
+ 8 = /dev/mmcblk1 Second SD/MMC card
+ ...
+
+ The start of next SD/MMC card can be configured with
+ CONFIG_MMC_BLOCK_MINORS, or overridden at boot/modprobe
+ time using the mmcblk.perdev_minors option. That would
+ bump the offset between each card to be the configured
+ value instead of the default 8.
+
+ 179 char CCube DVXChip-based PCI products
+ 0 = /dev/dvxirq0 First DVX device
+ 1 = /dev/dvxirq1 Second DVX device
+ ...
+
+ 180 char USB devices
+ 0 = /dev/usb/lp0 First USB printer
+ ...
+ 15 = /dev/usb/lp15 16th USB printer
+ 48 = /dev/usb/scanner0 First USB scanner
+ ...
+ 63 = /dev/usb/scanner15 16th USB scanner
+ 64 = /dev/usb/rio500 Diamond Rio 500
+ 65 = /dev/usb/usblcd USBLCD Interface (info@usblcd.de)
+ 66 = /dev/usb/cpad0 Synaptics cPad (mouse/LCD)
+ 96 = /dev/usb/hiddev0 1st USB HID device
+ ...
+ 111 = /dev/usb/hiddev15 16th USB HID device
+ 112 = /dev/usb/auer0 1st auerswald ISDN device
+ ...
+ 127 = /dev/usb/auer15 16th auerswald ISDN device
+ 128 = /dev/usb/brlvgr0 First Braille Voyager device
+ ...
+ 131 = /dev/usb/brlvgr3 Fourth Braille Voyager device
+ 132 = /dev/usb/idmouse ID Mouse (fingerprint scanner) device
+ 133 = /dev/usb/sisusbvga1 First SiSUSB VGA device
+ ...
+ 140 = /dev/usb/sisusbvga8 Eighth SISUSB VGA device
+ 144 = /dev/usb/lcd USB LCD device
+ 160 = /dev/usb/legousbtower0 1st USB Legotower device
+ ...
+ 175 = /dev/usb/legousbtower15 16th USB Legotower device
+ 176 = /dev/usb/usbtmc1 First USB TMC device
+ ...
+ 191 = /dev/usb/usbtmc16 16th USB TMC device
+ 192 = /dev/usb/yurex1 First USB Yurex device
+ ...
+ 209 = /dev/usb/yurex16 16th USB Yurex device
+
+ 180 block USB block devices
+ 0 = /dev/uba First USB block device
+ 8 = /dev/ubb Second USB block device
+ 16 = /dev/ubc Third USB block device
+ ...
+
+ 181 char Conrad Electronic parallel port radio clocks
+ 0 = /dev/pcfclock0 First Conrad radio clock
+ 1 = /dev/pcfclock1 Second Conrad radio clock
+ ...
+
+ 182 char Picture Elements THR2 binarizer
+ 0 = /dev/pethr0 First THR2 board
+ 1 = /dev/pethr1 Second THR2 board
+ ...
+
+ 183 char SST 5136-DN DeviceNet interface
+ 0 = /dev/ss5136dn0 First DeviceNet interface
+ 1 = /dev/ss5136dn1 Second DeviceNet interface
+ ...
+
+ This device used to be assigned to major number 144.
+ It had to be moved due to an unfortunate conflict.
+
+ 184 char Picture Elements' video simulator/sender
+ 0 = /dev/pevss0 First sender board
+ 1 = /dev/pevss1 Second sender board
+ ...
+
+ 185 char InterMezzo high availability file system
+ 0 = /dev/intermezzo0 First cache manager
+ 1 = /dev/intermezzo1 Second cache manager
+ ...
+
+ See http://web.archive.org/web/20080115195241/
+ http://inter-mezzo.org/index.html
+
+ 186 char Object-based storage control device
+ 0 = /dev/obd0 First obd control device
+ 1 = /dev/obd1 Second obd control device
+ ...
+
+ See ftp://ftp.lustre.org/pub/obd for code and information.
+
+ 187 char DESkey hardware encryption device
+ 0 = /dev/deskey0 First DES key
+ 1 = /dev/deskey1 Second DES key
+ ...
+
+ 188 char USB serial converters
+ 0 = /dev/ttyUSB0 First USB serial converter
+ 1 = /dev/ttyUSB1 Second USB serial converter
+ ...
+
+ 189 char USB serial converters - alternate devices
+ 0 = /dev/cuusb0 Callout device for ttyUSB0
+ 1 = /dev/cuusb1 Callout device for ttyUSB1
+ ...
+
+ 190 char Kansas City tracker/tuner card
+ 0 = /dev/kctt0 First KCT/T card
+ 1 = /dev/kctt1 Second KCT/T card
+ ...
+
+ 191 char Reserved for PCMCIA
+
+ 192 char Kernel profiling interface
+ 0 = /dev/profile Profiling control device
+ 1 = /dev/profile0 Profiling device for CPU 0
+ 2 = /dev/profile1 Profiling device for CPU 1
+ ...
+
+ 193 char Kernel event-tracing interface
+ 0 = /dev/trace Tracing control device
+ 1 = /dev/trace0 Tracing device for CPU 0
+ 2 = /dev/trace1 Tracing device for CPU 1
+ ...
+
+ 194 char linVideoStreams (LINVS)
+ 0 = /dev/mvideo/status0 Video compression status
+ 1 = /dev/mvideo/stream0 Video stream
+ 2 = /dev/mvideo/frame0 Single compressed frame
+ 3 = /dev/mvideo/rawframe0 Raw uncompressed frame
+ 4 = /dev/mvideo/codec0 Direct codec access
+ 5 = /dev/mvideo/video4linux0 Video4Linux compatibility
+
+ 16 = /dev/mvideo/status1 Second device
+ ...
+ 32 = /dev/mvideo/status2 Third device
+ ...
+ ...
+ 240 = /dev/mvideo/status15 16th device
+ ...
+
+ 195 char Nvidia graphics devices
+ 0 = /dev/nvidia0 First Nvidia card
+ 1 = /dev/nvidia1 Second Nvidia card
+ ...
+ 255 = /dev/nvidiactl Nvidia card control device
+
+ 196 char Tormenta T1 card
+ 0 = /dev/tor/0 Master control channel for all cards
+ 1 = /dev/tor/1 First DS0
+ 2 = /dev/tor/2 Second DS0
+ ...
+ 48 = /dev/tor/48 48th DS0
+ 49 = /dev/tor/49 First pseudo-channel
+ 50 = /dev/tor/50 Second pseudo-channel
+ ...
+
+ 197 char OpenTNF tracing facility
+ 0 = /dev/tnf/t0 Trace 0 data extraction
+ 1 = /dev/tnf/t1 Trace 1 data extraction
+ ...
+ 128 = /dev/tnf/status Tracing facility status
+ 130 = /dev/tnf/trace Tracing device
+
+ 198 char Total Impact TPMP2 quad coprocessor PCI card
+ 0 = /dev/tpmp2/0 First card
+ 1 = /dev/tpmp2/1 Second card
+ ...
+
+ 199 char Veritas volume manager (VxVM) volumes
+ 0 = /dev/vx/rdsk/*/* First volume
+ 1 = /dev/vx/rdsk/*/* Second volume
+ ...
+
+ 199 block Veritas volume manager (VxVM) volumes
+ 0 = /dev/vx/dsk/*/* First volume
+ 1 = /dev/vx/dsk/*/* Second volume
+ ...
+
+ The namespace in these directories is maintained by
+ the user space VxVM software.
+
+ 200 char Veritas VxVM configuration interface
+ 0 = /dev/vx/config Configuration access node
+ 1 = /dev/vx/trace Volume i/o trace access node
+ 2 = /dev/vx/iod Volume i/o daemon access node
+ 3 = /dev/vx/info Volume information access node
+ 4 = /dev/vx/task Volume tasks access node
+ 5 = /dev/vx/taskmon Volume tasks monitor daemon
+
+ 201 char Veritas VxVM dynamic multipathing driver
+ 0 = /dev/vx/rdmp/* First multipath device
+ 1 = /dev/vx/rdmp/* Second multipath device
+ ...
+ 201 block Veritas VxVM dynamic multipathing driver
+ 0 = /dev/vx/dmp/* First multipath device
+ 1 = /dev/vx/dmp/* Second multipath device
+ ...
+
+ The namespace in these directories is maintained by
+ the user space VxVM software.
+
+ 202 char CPU model-specific registers
+ 0 = /dev/cpu/0/msr MSRs on CPU 0
+ 1 = /dev/cpu/1/msr MSRs on CPU 1
+ ...
+
+ 202 block Xen Virtual Block Device
+ 0 = /dev/xvda First Xen VBD whole disk
+ 16 = /dev/xvdb Second Xen VBD whole disk
+ 32 = /dev/xvdc Third Xen VBD whole disk
+ ...
+ 240 = /dev/xvdp Sixteenth Xen VBD whole disk
+
+ Partitions are handled in the same way as for IDE
+ disks (see major number 3) except that the limit on
+ partitions is 15.
+
+ 203 char CPU CPUID information
+ 0 = /dev/cpu/0/cpuid CPUID on CPU 0
+ 1 = /dev/cpu/1/cpuid CPUID on CPU 1
+ ...
+
+ 204 char Low-density serial ports
+ 0 = /dev/ttyLU0 LinkUp Systems L72xx UART - port 0
+ 1 = /dev/ttyLU1 LinkUp Systems L72xx UART - port 1
+ 2 = /dev/ttyLU2 LinkUp Systems L72xx UART - port 2
+ 3 = /dev/ttyLU3 LinkUp Systems L72xx UART - port 3
+ 4 = /dev/ttyFB0 Intel Footbridge (ARM)
+ 5 = /dev/ttySA0 StrongARM builtin serial port 0
+ 6 = /dev/ttySA1 StrongARM builtin serial port 1
+ 7 = /dev/ttySA2 StrongARM builtin serial port 2
+ 8 = /dev/ttySC0 SCI serial port (SuperH) - port 0
+ 9 = /dev/ttySC1 SCI serial port (SuperH) - port 1
+ 10 = /dev/ttySC2 SCI serial port (SuperH) - port 2
+ 11 = /dev/ttySC3 SCI serial port (SuperH) - port 3
+ 12 = /dev/ttyFW0 Firmware console - port 0
+ 13 = /dev/ttyFW1 Firmware console - port 1
+ 14 = /dev/ttyFW2 Firmware console - port 2
+ 15 = /dev/ttyFW3 Firmware console - port 3
+ 16 = /dev/ttyAM0 ARM "AMBA" serial port 0
+ ...
+ 31 = /dev/ttyAM15 ARM "AMBA" serial port 15
+ 32 = /dev/ttyDB0 DataBooster serial port 0
+ ...
+ 39 = /dev/ttyDB7 DataBooster serial port 7
+ 40 = /dev/ttySG0 SGI Altix console port
+ 41 = /dev/ttySMX0 Motorola i.MX - port 0
+ 42 = /dev/ttySMX1 Motorola i.MX - port 1
+ 43 = /dev/ttySMX2 Motorola i.MX - port 2
+ 44 = /dev/ttyMM0 Marvell MPSC - port 0
+ 45 = /dev/ttyMM1 Marvell MPSC - port 1
+ 46 = /dev/ttyCPM0 PPC CPM (SCC or SMC) - port 0
+ ...
+ 47 = /dev/ttyCPM5 PPC CPM (SCC or SMC) - port 5
+ 50 = /dev/ttyIOC0 Altix serial card
+ ...
+ 81 = /dev/ttyIOC31 Altix serial card
+ 82 = /dev/ttyVR0 NEC VR4100 series SIU
+ 83 = /dev/ttyVR1 NEC VR4100 series DSIU
+ 84 = /dev/ttyIOC84 Altix ioc4 serial card
+ ...
+ 115 = /dev/ttyIOC115 Altix ioc4 serial card
+ 116 = /dev/ttySIOC0 Altix ioc3 serial card
+ ...
+ 147 = /dev/ttySIOC31 Altix ioc3 serial card
+ 148 = /dev/ttyPSC0 PPC PSC - port 0
+ ...
+ 153 = /dev/ttyPSC5 PPC PSC - port 5
+ 154 = /dev/ttyAT0 ATMEL serial port 0
+ ...
+ 169 = /dev/ttyAT15 ATMEL serial port 15
+ 170 = /dev/ttyNX0 Hilscher netX serial port 0
+ ...
+ 185 = /dev/ttyNX15 Hilscher netX serial port 15
+ 186 = /dev/ttyJ0 JTAG1 DCC protocol based serial port emulation
+ 187 = /dev/ttyUL0 Xilinx uartlite - port 0
+ ...
+ 190 = /dev/ttyUL3 Xilinx uartlite - port 3
+ 191 = /dev/xvc0 Xen virtual console - port 0
+ 192 = /dev/ttyPZ0 pmac_zilog - port 0
+ ...
+ 195 = /dev/ttyPZ3 pmac_zilog - port 3
+ 196 = /dev/ttyTX0 TX39/49 serial port 0
+ ...
+ 204 = /dev/ttyTX7 TX39/49 serial port 7
+ 205 = /dev/ttySC0 SC26xx serial port 0
+ 206 = /dev/ttySC1 SC26xx serial port 1
+ 207 = /dev/ttySC2 SC26xx serial port 2
+ 208 = /dev/ttySC3 SC26xx serial port 3
+ 209 = /dev/ttyMAX0 MAX3100 serial port 0
+ 210 = /dev/ttyMAX1 MAX3100 serial port 1
+ 211 = /dev/ttyMAX2 MAX3100 serial port 2
+ 212 = /dev/ttyMAX3 MAX3100 serial port 3
+
+ 205 char Low-density serial ports (alternate device)
+ 0 = /dev/culu0 Callout device for ttyLU0
+ 1 = /dev/culu1 Callout device for ttyLU1
+ 2 = /dev/culu2 Callout device for ttyLU2
+ 3 = /dev/culu3 Callout device for ttyLU3
+ 4 = /dev/cufb0 Callout device for ttyFB0
+ 5 = /dev/cusa0 Callout device for ttySA0
+ 6 = /dev/cusa1 Callout device for ttySA1
+ 7 = /dev/cusa2 Callout device for ttySA2
+ 8 = /dev/cusc0 Callout device for ttySC0
+ 9 = /dev/cusc1 Callout device for ttySC1
+ 10 = /dev/cusc2 Callout device for ttySC2
+ 11 = /dev/cusc3 Callout device for ttySC3
+ 12 = /dev/cufw0 Callout device for ttyFW0
+ 13 = /dev/cufw1 Callout device for ttyFW1
+ 14 = /dev/cufw2 Callout device for ttyFW2
+ 15 = /dev/cufw3 Callout device for ttyFW3
+ 16 = /dev/cuam0 Callout device for ttyAM0
+ ...
+ 31 = /dev/cuam15 Callout device for ttyAM15
+ 32 = /dev/cudb0 Callout device for ttyDB0
+ ...
+ 39 = /dev/cudb7 Callout device for ttyDB7
+ 40 = /dev/cusg0 Callout device for ttySG0
+ 41 = /dev/ttycusmx0 Callout device for ttySMX0
+ 42 = /dev/ttycusmx1 Callout device for ttySMX1
+ 43 = /dev/ttycusmx2 Callout device for ttySMX2
+ 46 = /dev/cucpm0 Callout device for ttyCPM0
+ ...
+ 49 = /dev/cucpm5 Callout device for ttyCPM5
+ 50 = /dev/cuioc40 Callout device for ttyIOC40
+ ...
+ 81 = /dev/cuioc431 Callout device for ttyIOC431
+ 82 = /dev/cuvr0 Callout device for ttyVR0
+ 83 = /dev/cuvr1 Callout device for ttyVR1
+
+ 206 char OnStream SC-x0 tape devices
+ 0 = /dev/osst0 First OnStream SCSI tape, mode 0
+ 1 = /dev/osst1 Second OnStream SCSI tape, mode 0
+ ...
+ 32 = /dev/osst0l First OnStream SCSI tape, mode 1
+ 33 = /dev/osst1l Second OnStream SCSI tape, mode 1
+ ...
+ 64 = /dev/osst0m First OnStream SCSI tape, mode 2
+ 65 = /dev/osst1m Second OnStream SCSI tape, mode 2
+ ...
+ 96 = /dev/osst0a First OnStream SCSI tape, mode 3
+ 97 = /dev/osst1a Second OnStream SCSI tape, mode 3
+ ...
+ 128 = /dev/nosst0 No rewind version of /dev/osst0
+ 129 = /dev/nosst1 No rewind version of /dev/osst1
+ ...
+ 160 = /dev/nosst0l No rewind version of /dev/osst0l
+ 161 = /dev/nosst1l No rewind version of /dev/osst1l
+ ...
+ 192 = /dev/nosst0m No rewind version of /dev/osst0m
+ 193 = /dev/nosst1m No rewind version of /dev/osst1m
+ ...
+ 224 = /dev/nosst0a No rewind version of /dev/osst0a
+ 225 = /dev/nosst1a No rewind version of /dev/osst1a
+ ...
+
+ The OnStream SC-x0 SCSI tapes do not support the
+ standard SCSI SASD command set and therefore need
+ their own driver "osst". Note that the IDE, USB (and
+ maybe ParPort) versions may be driven via ide-scsi or
+ usb-storage SCSI emulation and this osst device and
+ driver as well. The ADR-x0 drives are QIC-157
+ compliant and don't need osst.
+
+ 207 char Compaq ProLiant health feature indicate
+ 0 = /dev/cpqhealth/cpqw Redirector interface
+ 1 = /dev/cpqhealth/crom EISA CROM
+ 2 = /dev/cpqhealth/cdt Data Table
+ 3 = /dev/cpqhealth/cevt Event Log
+ 4 = /dev/cpqhealth/casr Automatic Server Recovery
+ 5 = /dev/cpqhealth/cecc ECC Memory
+ 6 = /dev/cpqhealth/cmca Machine Check Architecture
+ 7 = /dev/cpqhealth/ccsm Deprecated CDT
+ 8 = /dev/cpqhealth/cnmi NMI Handling
+ 9 = /dev/cpqhealth/css Sideshow Management
+ 10 = /dev/cpqhealth/cram CMOS interface
+ 11 = /dev/cpqhealth/cpci PCI IRQ interface
+
+ 208 char User space serial ports
+ 0 = /dev/ttyU0 First user space serial port
+ 1 = /dev/ttyU1 Second user space serial port
+ ...
+
+ 209 char User space serial ports (alternate devices)
+ 0 = /dev/cuu0 Callout device for ttyU0
+ 1 = /dev/cuu1 Callout device for ttyU1
+ ...
+
+ 210 char SBE, Inc. sync/async serial card
+ 0 = /dev/sbei/wxcfg0 Configuration device for board 0
+ 1 = /dev/sbei/dld0 Download device for board 0
+ 2 = /dev/sbei/wan00 WAN device, port 0, board 0
+ 3 = /dev/sbei/wan01 WAN device, port 1, board 0
+ 4 = /dev/sbei/wan02 WAN device, port 2, board 0
+ 5 = /dev/sbei/wan03 WAN device, port 3, board 0
+ 6 = /dev/sbei/wanc00 WAN clone device, port 0, board 0
+ 7 = /dev/sbei/wanc01 WAN clone device, port 1, board 0
+ 8 = /dev/sbei/wanc02 WAN clone device, port 2, board 0
+ 9 = /dev/sbei/wanc03 WAN clone device, port 3, board 0
+ 10 = /dev/sbei/wxcfg1 Configuration device for board 1
+ 11 = /dev/sbei/dld1 Download device for board 1
+ 12 = /dev/sbei/wan10 WAN device, port 0, board 1
+ 13 = /dev/sbei/wan11 WAN device, port 1, board 1
+ 14 = /dev/sbei/wan12 WAN device, port 2, board 1
+ 15 = /dev/sbei/wan13 WAN device, port 3, board 1
+ 16 = /dev/sbei/wanc10 WAN clone device, port 0, board 1
+ 17 = /dev/sbei/wanc11 WAN clone device, port 1, board 1
+ 18 = /dev/sbei/wanc12 WAN clone device, port 2, board 1
+ 19 = /dev/sbei/wanc13 WAN clone device, port 3, board 1
+ ...
+
+ Yes, each board is really spaced 10 (decimal) apart.
+
+ 211 char Addinum CPCI1500 digital I/O card
+ 0 = /dev/addinum/cpci1500/0 First CPCI1500 card
+ 1 = /dev/addinum/cpci1500/1 Second CPCI1500 card
+ ...
+
+ 212 char LinuxTV.org DVB driver subsystem
+ 0 = /dev/dvb/adapter0/video0 first video decoder of first card
+ 1 = /dev/dvb/adapter0/audio0 first audio decoder of first card
+ 2 = /dev/dvb/adapter0/sec0 (obsolete/unused)
+ 3 = /dev/dvb/adapter0/frontend0 first frontend device of first card
+ 4 = /dev/dvb/adapter0/demux0 first demux device of first card
+ 5 = /dev/dvb/adapter0/dvr0 first digital video recoder device of first card
+ 6 = /dev/dvb/adapter0/ca0 first common access port of first card
+ 7 = /dev/dvb/adapter0/net0 first network device of first card
+ 8 = /dev/dvb/adapter0/osd0 first on-screen-display device of first card
+ 9 = /dev/dvb/adapter0/video1 second video decoder of first card
+ ...
+ 64 = /dev/dvb/adapter1/video0 first video decoder of second card
+ ...
+ 128 = /dev/dvb/adapter2/video0 first video decoder of third card
+ ...
+ 196 = /dev/dvb/adapter3/video0 first video decoder of fourth card
+
+ 216 char Bluetooth RFCOMM TTY devices
+ 0 = /dev/rfcomm0 First Bluetooth RFCOMM TTY device
+ 1 = /dev/rfcomm1 Second Bluetooth RFCOMM TTY device
+ ...
+
+ 217 char Bluetooth RFCOMM TTY devices (alternate devices)
+ 0 = /dev/curf0 Callout device for rfcomm0
+ 1 = /dev/curf1 Callout device for rfcomm1
+ ...
+
+ 218 char The Logical Company bus Unibus/Qbus adapters
+ 0 = /dev/logicalco/bci/0 First bus adapter
+ 1 = /dev/logicalco/bci/1 First bus adapter
+ ...
+
+ 219 char The Logical Company DCI-1300 digital I/O card
+ 0 = /dev/logicalco/dci1300/0 First DCI-1300 card
+ 1 = /dev/logicalco/dci1300/1 Second DCI-1300 card
+ ...
+
+ 220 char Myricom Myrinet "GM" board
+ 0 = /dev/myricom/gm0 First Myrinet GM board
+ 1 = /dev/myricom/gmp0 First board "root access"
+ 2 = /dev/myricom/gm1 Second Myrinet GM board
+ 3 = /dev/myricom/gmp1 Second board "root access"
+ ...
+
+ 221 char VME bus
+ 0 = /dev/bus/vme/m0 First master image
+ 1 = /dev/bus/vme/m1 Second master image
+ 2 = /dev/bus/vme/m2 Third master image
+ 3 = /dev/bus/vme/m3 Fourth master image
+ 4 = /dev/bus/vme/s0 First slave image
+ 5 = /dev/bus/vme/s1 Second slave image
+ 6 = /dev/bus/vme/s2 Third slave image
+ 7 = /dev/bus/vme/s3 Fourth slave image
+ 8 = /dev/bus/vme/ctl Control
+
+ It is expected that all VME bus drivers will use the
+ same interface. For interface documentation see
+ http://www.vmelinux.org/.
+
+ 224 char A2232 serial card
+ 0 = /dev/ttyY0 First A2232 port
+ 1 = /dev/ttyY1 Second A2232 port
+ ...
+
+ 225 char A2232 serial card (alternate devices)
+ 0 = /dev/cuy0 Callout device for ttyY0
+ 1 = /dev/cuy1 Callout device for ttyY1
+ ...
+
+ 226 char Direct Rendering Infrastructure (DRI)
+ 0 = /dev/dri/card0 First graphics card
+ 1 = /dev/dri/card1 Second graphics card
+ ...
+
+ 227 char IBM 3270 terminal Unix tty access
+ 1 = /dev/3270/tty1 First 3270 terminal
+ 2 = /dev/3270/tty2 Seconds 3270 terminal
+ ...
+
+ 228 char IBM 3270 terminal block-mode access
+ 0 = /dev/3270/tub Controlling interface
+ 1 = /dev/3270/tub1 First 3270 terminal
+ 2 = /dev/3270/tub2 Second 3270 terminal
+ ...
+
+ 229 char IBM iSeries/pSeries virtual console
+ 0 = /dev/hvc0 First console port
+ 1 = /dev/hvc1 Second console port
+ ...
+
+ 230 char IBM iSeries virtual tape
+ 0 = /dev/iseries/vt0 First virtual tape, mode 0
+ 1 = /dev/iseries/vt1 Second virtual tape, mode 0
+ ...
+ 32 = /dev/iseries/vt0l First virtual tape, mode 1
+ 33 = /dev/iseries/vt1l Second virtual tape, mode 1
+ ...
+ 64 = /dev/iseries/vt0m First virtual tape, mode 2
+ 65 = /dev/iseries/vt1m Second virtual tape, mode 2
+ ...
+ 96 = /dev/iseries/vt0a First virtual tape, mode 3
+ 97 = /dev/iseries/vt1a Second virtual tape, mode 3
+ ...
+ 128 = /dev/iseries/nvt0 First virtual tape, mode 0, no rewind
+ 129 = /dev/iseries/nvt1 Second virtual tape, mode 0, no rewind
+ ...
+ 160 = /dev/iseries/nvt0l First virtual tape, mode 1, no rewind
+ 161 = /dev/iseries/nvt1l Second virtual tape, mode 1, no rewind
+ ...
+ 192 = /dev/iseries/nvt0m First virtual tape, mode 2, no rewind
+ 193 = /dev/iseries/nvt1m Second virtual tape, mode 2, no rewind
+ ...
+ 224 = /dev/iseries/nvt0a First virtual tape, mode 3, no rewind
+ 225 = /dev/iseries/nvt1a Second virtual tape, mode 3, no rewind
+ ...
+
+ "No rewind" refers to the omission of the default
+ automatic rewind on device close. The MTREW or MTOFFL
+ ioctl()'s can be used to rewind the tape regardless of
+ the device used to access it.
+
+ 231 char InfiniBand
+ 0 = /dev/infiniband/umad0
+ 1 = /dev/infiniband/umad1
+ ...
+ 63 = /dev/infiniband/umad63 63rd InfiniBandMad device
+ 64 = /dev/infiniband/issm0 First InfiniBand IsSM device
+ 65 = /dev/infiniband/issm1 Second InfiniBand IsSM device
+ ...
+ 127 = /dev/infiniband/issm63 63rd InfiniBand IsSM device
+ 128 = /dev/infiniband/uverbs0 First InfiniBand verbs device
+ 129 = /dev/infiniband/uverbs1 Second InfiniBand verbs device
+ ...
+ 159 = /dev/infiniband/uverbs31 31st InfiniBand verbs device
+
+ 232 char Biometric Devices
+ 0 = /dev/biometric/sensor0/fingerprint first fingerprint sensor on first device
+ 1 = /dev/biometric/sensor0/iris first iris sensor on first device
+ 2 = /dev/biometric/sensor0/retina first retina sensor on first device
+ 3 = /dev/biometric/sensor0/voiceprint first voiceprint sensor on first device
+ 4 = /dev/biometric/sensor0/facial first facial sensor on first device
+ 5 = /dev/biometric/sensor0/hand first hand sensor on first device
+ ...
+ 10 = /dev/biometric/sensor1/fingerprint first fingerprint sensor on second device
+ ...
+ 20 = /dev/biometric/sensor2/fingerprint first fingerprint sensor on third device
+ ...
+
+ 233 char PathScale InfiniPath interconnect
+ 0 = /dev/ipath Primary device for programs (any unit)
+ 1 = /dev/ipath0 Access specifically to unit 0
+ 2 = /dev/ipath1 Access specifically to unit 1
+ ...
+ 4 = /dev/ipath3 Access specifically to unit 3
+ 129 = /dev/ipath_sma Device used by Subnet Management Agent
+ 130 = /dev/ipath_diag Device used by diagnostics programs
+
+ 234-254 char RESERVED FOR DYNAMIC ASSIGNMENT
+ Character devices that request a dynamic allocation of major number will
+ take numbers starting from 254 and downward.
+
+ 240-254 block LOCAL/EXPERIMENTAL USE
+ Allocated for local/experimental use. For devices not
+ assigned official numbers, these ranges should be
+ used in order to avoid conflicting with future assignments.
+
+ 255 char RESERVED
+
+ 255 block RESERVED
+
+ This major is reserved to assist the expansion to a
+ larger number space. No device nodes with this major
+ should ever be created on the filesystem.
+ (This is probably not true anymore, but I'll leave it
+ for now /Torben)
+
+ ---LARGE MAJORS!!!!!---
+
+ 256 char Equinox SST multi-port serial boards
+ 0 = /dev/ttyEQ0 First serial port on first Equinox SST board
+ 127 = /dev/ttyEQ127 Last serial port on first Equinox SST board
+ 128 = /dev/ttyEQ128 First serial port on second Equinox SST board
+ ...
+ 1027 = /dev/ttyEQ1027 Last serial port on eighth Equinox SST board
+
+ 256 block Resident Flash Disk Flash Translation Layer
+ 0 = /dev/rfda First RFD FTL layer
+ 16 = /dev/rfdb Second RFD FTL layer
+ ...
+ 240 = /dev/rfdp 16th RFD FTL layer
+
+ 257 char Phoenix Technologies Cryptographic Services Driver
+ 0 = /dev/ptlsec Crypto Services Driver
+
+ 257 block SSFDC Flash Translation Layer filesystem
+ 0 = /dev/ssfdca First SSFDC layer
+ 8 = /dev/ssfdcb Second SSFDC layer
+ 16 = /dev/ssfdcc Third SSFDC layer
+ 24 = /dev/ssfdcd 4th SSFDC layer
+ 32 = /dev/ssfdce 5th SSFDC layer
+ 40 = /dev/ssfdcf 6th SSFDC layer
+ 48 = /dev/ssfdcg 7th SSFDC layer
+ 56 = /dev/ssfdch 8th SSFDC layer
+
+ 258 block ROM/Flash read-only translation layer
+ 0 = /dev/blockrom0 First ROM card's translation layer interface
+ 1 = /dev/blockrom1 Second ROM card's translation layer interface
+ ...
+
+ 259 block Block Extended Major
+ Used dynamically to hold additional partition minor
+ numbers and allow large numbers of partitions per device
+
+ 259 char FPGA configuration interfaces
+ 0 = /dev/icap0 First Xilinx internal configuration
+ 1 = /dev/icap1 Second Xilinx internal configuration
+
+ 260 char OSD (Object-based-device) SCSI Device
+ 0 = /dev/osd0 First OSD Device
+ 1 = /dev/osd1 Second OSD Device
+ ...
+ 255 = /dev/osd255 256th OSD Device
+
+
+Additional ``/dev/`` directory entries
+--------------------------------------
+
+This section details additional entries that should or may exist in
+the /dev directory. It is preferred that symbolic links use the same
+form (absolute or relative) as is indicated here. Links are
+classified as "hard" or "symbolic" depending on the preferred type of
+link; if possible, the indicated type of link should be used.
+
+Compulsory links
+++++++++++++++++
+
+These links should exist on all systems:
+
+=============== =============== =============== ===============================
+/dev/fd /proc/self/fd symbolic File descriptors
+/dev/stdin fd/0 symbolic stdin file descriptor
+/dev/stdout fd/1 symbolic stdout file descriptor
+/dev/stderr fd/2 symbolic stderr file descriptor
+/dev/nfsd socksys symbolic Required by iBCS-2
+/dev/X0R null symbolic Required by iBCS-2
+=============== =============== =============== ===============================
+
+Note: ``/dev/X0R`` is <letter X>-<digit 0>-<letter R>.
+
+Recommended links
++++++++++++++++++
+
+It is recommended that these links exist on all systems:
+
+
+=============== =============== =============== ===============================
+/dev/core /proc/kcore symbolic Backward compatibility
+/dev/ramdisk ram0 symbolic Backward compatibility
+/dev/ftape qft0 symbolic Backward compatibility
+/dev/bttv0 video0 symbolic Backward compatibility
+/dev/radio radio0 symbolic Backward compatibility
+/dev/i2o* /dev/i2o/* symbolic Backward compatibility
+/dev/scd? sr? hard Alternate SCSI CD-ROM name
+=============== =============== =============== ===============================
+
+Locally defined links
++++++++++++++++++++++
+
+The following links may be established locally to conform to the
+configuration of the system. This is merely a tabulation of existing
+practice, and does not constitute a recommendation. However, if they
+exist, they should have the following uses.
+
+=============== =============== =============== ===============================
+/dev/mouse mouse port symbolic Current mouse device
+/dev/tape tape device symbolic Current tape device
+/dev/cdrom CD-ROM device symbolic Current CD-ROM device
+/dev/cdwriter CD-writer symbolic Current CD-writer device
+/dev/scanner scanner symbolic Current scanner device
+/dev/modem modem port symbolic Current dialout device
+/dev/root root device symbolic Current root filesystem
+/dev/swap swap device symbolic Current swap device
+=============== =============== =============== ===============================
+
+``/dev/modem`` should not be used for a modem which supports dialin as
+well as dialout, as it tends to cause lock file problems. If it
+exists, ``/dev/modem`` should point to the appropriate primary TTY device
+(the use of the alternate callout devices is deprecated).
+
+For SCSI devices, ``/dev/tape`` and ``/dev/cdrom`` should point to the
+*cooked* devices (``/dev/st*`` and ``/dev/sr*``, respectively), whereas
+``/dev/cdwriter`` and /dev/scanner should point to the appropriate generic
+SCSI devices (/dev/sg*).
+
+``/dev/mouse`` may point to a primary serial TTY device, a hardware mouse
+device, or a socket for a mouse driver program (e.g. ``/dev/gpmdata``).
+
+Sockets and pipes
++++++++++++++++++
+
+Non-transient sockets and named pipes may exist in /dev. Common entries are:
+
+=============== =============== ===============================================
+/dev/printer socket lpd local socket
+/dev/log socket syslog local socket
+/dev/gpmdata socket gpm mouse multiplexer
+=============== =============== ===============================================
+
+Mount points
+++++++++++++
+
+The following names are reserved for mounting special filesystems
+under /dev. These special filesystems provide kernel interfaces that
+cannot be provided with standard device nodes.
+
+=============== =============== ===============================================
+/dev/pts devpts PTY slave filesystem
+/dev/shm tmpfs POSIX shared memory maintenance access
+=============== =============== ===============================================
+
+Terminal devices
+----------------
+
+Terminal, or TTY devices are a special class of character devices. A
+terminal device is any device that could act as a controlling terminal
+for a session; this includes virtual consoles, serial ports, and
+pseudoterminals (PTYs).
+
+All terminal devices share a common set of capabilities known as line
+disciplines; these include the common terminal line discipline as well
+as SLIP and PPP modes.
+
+All terminal devices are named similarly; this section explains the
+naming and use of the various types of TTYs. Note that the naming
+conventions include several historical warts; some of these are
+Linux-specific, some were inherited from other systems, and some
+reflect Linux outgrowing a borrowed convention.
+
+A hash mark (``#``) in a device name is used here to indicate a decimal
+number without leading zeroes.
+
+Virtual consoles and the console device
++++++++++++++++++++++++++++++++++++++++
+
+Virtual consoles are full-screen terminal displays on the system video
+monitor. Virtual consoles are named ``/dev/tty#``, with numbering
+starting at ``/dev/tty1``; ``/dev/tty0`` is the current virtual console.
+``/dev/tty0`` is the device that should be used to access the system video
+card on those architectures for which the frame buffer devices
+(``/dev/fb*``) are not applicable. Do not use ``/dev/console``
+for this purpose.
+
+The console device, ``/dev/console``, is the device to which system
+messages should be sent, and on which logins should be permitted in
+single-user mode. Starting with Linux 2.1.71, ``/dev/console`` is managed
+by the kernel; for previous versions it should be a symbolic link to
+either ``/dev/tty0``, a specific virtual console such as ``/dev/tty1``, or to
+a serial port primary (``tty*``, not ``cu*``) device, depending on the
+configuration of the system.
+
+Serial ports
+++++++++++++
+
+Serial ports are RS-232 serial ports and any device which simulates
+one, either in hardware (such as internal modems) or in software (such
+as the ISDN driver.) Under Linux, each serial ports has two device
+names, the primary or callin device and the alternate or callout one.
+Each kind of device is indicated by a different letter. For any
+letter X, the names of the devices are ``/dev/ttyX#`` and ``/dev/cux#``,
+respectively; for historical reasons, ``/dev/ttyS#`` and ``/dev/ttyC#``
+correspond to ``/dev/cua#`` and ``/dev/cub#``. In the future, it should be
+expected that multiple letters will be used; all letters will be upper
+case for the "tty" device (e.g. ``/dev/ttyDP#``) and lower case for the
+"cu" device (e.g. ``/dev/cudp#``).
+
+The names ``/dev/ttyQ#`` and ``/dev/cuq#`` are reserved for local use.
+
+The alternate devices provide for kernel-based exclusion and somewhat
+different defaults than the primary devices. Their main purpose is to
+allow the use of serial ports with programs with no inherent or broken
+support for serial ports. Their use is deprecated, and they may be
+removed from a future version of Linux.
+
+Arbitration of serial ports is provided by the use of lock files with
+the names ``/var/lock/LCK..ttyX#``. The contents of the lock file should
+be the PID of the locking process as an ASCII number.
+
+It is common practice to install links such as /dev/modem
+which point to serial ports. In order to ensure proper locking in the
+presence of these links, it is recommended that software chase
+symlinks and lock all possible names; additionally, it is recommended
+that a lock file be installed with the corresponding alternate
+device. In order to avoid deadlocks, it is recommended that the locks
+are acquired in the following order, and released in the reverse:
+
+ 1. The symbolic link name, if any (``/var/lock/LCK..modem``)
+ 2. The "tty" name (``/var/lock/LCK..ttyS2``)
+ 3. The alternate device name (``/var/lock/LCK..cua2``)
+
+In the case of nested symbolic links, the lock files should be
+installed in the order the symlinks are resolved.
+
+Under no circumstances should an application hold a lock while waiting
+for another to be released. In addition, applications which attempt
+to create lock files for the corresponding alternate device names
+should take into account the possibility of being used on a non-serial
+port TTY, for which no alternate device would exist.
+
+Pseudoterminals (PTYs)
+++++++++++++++++++++++
+
+Pseudoterminals, or PTYs, are used to create login sessions or provide
+other capabilities requiring a TTY line discipline (including SLIP or
+PPP capability) to arbitrary data-generation processes. Each PTY has
+a master side, named ``/dev/pty[p-za-e][0-9a-f]``, and a slave side, named
+``/dev/tty[p-za-e][0-9a-f]``. The kernel arbitrates the use of PTYs by
+allowing each master side to be opened only once.
+
+Once the master side has been opened, the corresponding slave device
+can be used in the same manner as any TTY device. The master and
+slave devices are connected by the kernel, generating the equivalent
+of a bidirectional pipe with TTY capabilities.
+
+Recent versions of the Linux kernels and GNU libc contain support for
+the System V/Unix98 naming scheme for PTYs, which assigns a common
+device, ``/dev/ptmx``, to all the masters (opening it will automatically
+give you a previously unassigned PTY) and a subdirectory, ``/dev/pts``,
+for the slaves; the slaves are named with decimal integers (``/dev/pts/#``
+in our notation). This removes the problem of exhausting the
+namespace and enables the kernel to automatically create the device
+nodes for the slaves on demand using the "devpts" filesystem.
--- /dev/null
+Dynamic debug
++++++++++++++
+
+
+Introduction
+============
+
+This document describes how to use the dynamic debug (dyndbg) feature.
+
+Dynamic debug is designed to allow you to dynamically enable/disable
+kernel code to obtain additional kernel information. Currently, if
+``CONFIG_DYNAMIC_DEBUG`` is set, then all ``pr_debug()``/``dev_dbg()`` and
+``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
+enabled per-callsite.
+
+If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
+shortcut for ``print_hex_dump(KERN_DEBUG)``.
+
+For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
+its ``prefix_str`` argument, if it is constant string; or ``hexdump``
+in case ``prefix_str`` is build dynamically.
+
+Dynamic debug has even more useful features:
+
+ * Simple query language allows turning on and off debugging
+ statements by matching any combination of 0 or 1 of:
+
+ - source filename
+ - function name
+ - line number (including ranges of line numbers)
+ - module name
+ - format string
+
+ * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
+ which can be read to display the complete list of known debug
+ statements, to help guide you
+
+Controlling dynamic debug Behaviour
+===================================
+
+The behaviour of ``pr_debug()``/``dev_dbg()`` are controlled via writing to a
+control file in the 'debugfs' filesystem. Thus, you must first mount
+the debugfs filesystem, in order to make use of this feature.
+Subsequently, we refer to the control file as:
+``<debugfs>/dynamic_debug/control``. For example, if you want to enable
+printing from source file ``svcsock.c``, line 1603 you simply do::
+
+ nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/control
+
+If you make a mistake with the syntax, the write will fail thus::
+
+ nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
+ <debugfs>/dynamic_debug/control
+ -bash: echo: write error: Invalid argument
+
+Viewing Dynamic Debug Behaviour
+===============================
+
+You can view the currently configured behaviour of all the debug
+statements via::
+
+ nullarbor:~ # cat <debugfs>/dynamic_debug/control
+ # filename:lineno [module]function flags format
+ /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
+ /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline : %d\012"
+ /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth : %d\012"
+ /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests : %d\012"
+ ...
+
+
+You can also apply standard Unix text manipulation filters to this
+data, e.g.::
+
+ nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control | wc -l
+ 62
+
+ nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
+ 42
+
+The third column shows the currently enabled flags for each debug
+statement callsite (see below for definitions of the flags). The
+default value, with no flags enabled, is ``=_``. So you can view all
+the debug statement callsites with any non-default flags::
+
+ nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
+ # filename:lineno [module]function flags format
+ /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
+
+Command Language Reference
+==========================
+
+At the lexical level, a command comprises a sequence of words separated
+by spaces or tabs. So these are all equivalent::
+
+ nullarbor:~ # echo -c 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/control
+ nullarbor:~ # echo -c ' file svcsock.c line 1603 +p ' >
+ <debugfs>/dynamic_debug/control
+ nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/control
+
+Command submissions are bounded by a write() system call.
+Multiple commands can be written together, separated by ``;`` or ``\n``::
+
+ ~# echo "func pnpacpi_get_resources +p; func pnp_assign_mem +p" \
+ > <debugfs>/dynamic_debug/control
+
+If your query set is big, you can batch them too::
+
+ ~# cat query-batch-file > <debugfs>/dynamic_debug/control
+
+A another way is to use wildcard. The match rule support ``*`` (matches
+zero or more characters) and ``?`` (matches exactly one character).For
+example, you can match all usb drivers::
+
+ ~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
+
+At the syntactical level, a command comprises a sequence of match
+specifications, followed by a flags change specification::
+
+ command ::= match-spec* flags-spec
+
+The match-spec's are used to choose a subset of the known pr_debug()
+callsites to which to apply the flags-spec. Think of them as a query
+with implicit ANDs between each pair. Note that an empty list of
+match-specs will select all debug statement callsites.
+
+A match specification comprises a keyword, which controls the
+attribute of the callsite to be compared, and a value to compare
+against. Possible keywords are:::
+
+ match-spec ::= 'func' string |
+ 'file' string |
+ 'module' string |
+ 'format' string |
+ 'line' line-range
+
+ line-range ::= lineno |
+ '-'lineno |
+ lineno'-' |
+ lineno'-'lineno
+
+ lineno ::= unsigned-int
+
+.. note::
+
+ ``line-range`` cannot contain space, e.g.
+ "1-30" is valid range but "1 - 30" is not.
+
+
+The meanings of each keyword are:
+
+func
+ The given string is compared against the function name
+ of each callsite. Example::
+
+ func svc_tcp_accept
+
+file
+ The given string is compared against either the full pathname, the
+ src-root relative pathname, or the basename of the source file of
+ each callsite. Examples::
+
+ file svcsock.c
+ file kernel/freezer.c
+ file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c
+
+module
+ The given string is compared against the module name
+ of each callsite. The module name is the string as
+ seen in ``lsmod``, i.e. without the directory or the ``.ko``
+ suffix and with ``-`` changed to ``_``. Examples::
+
+ module sunrpc
+ module nfsd
+
+format
+ The given string is searched for in the dynamic debug format
+ string. Note that the string does not need to match the
+ entire format, only some part. Whitespace and other
+ special characters can be escaped using C octal character
+ escape ``\ooo`` notation, e.g. the space character is ``\040``.
+ Alternatively, the string can be enclosed in double quote
+ characters (``"``) or single quote characters (``'``).
+ Examples::
+
+ format svcrdma: // many of the NFS/RDMA server pr_debugs
+ format readahead // some pr_debugs in the readahead cache
+ format nfsd:\040SETATTR // one way to match a format with whitespace
+ format "nfsd: SETATTR" // a neater way to match a format with whitespace
+ format 'nfsd: SETATTR' // yet another way to match a format with whitespace
+
+line
+ The given line number or range of line numbers is compared
+ against the line number of each ``pr_debug()`` callsite. A single
+ line number matches the callsite line number exactly. A
+ range of line numbers matches any callsite between the first
+ and last line number inclusive. An empty first number means
+ the first line in the file, an empty line number means the
+ last number in the file. Examples::
+
+ line 1603 // exactly line 1603
+ line 1600-1605 // the six lines from line 1600 to line 1605
+ line -1605 // the 1605 lines from line 1 to line 1605
+ line 1600- // all lines from line 1600 to the end of the file
+
+The flags specification comprises a change operation followed
+by one or more flag characters. The change operation is one
+of the characters::
+
+ - remove the given flags
+ + add the given flags
+ = set the flags to the given flags
+
+The flags are::
+
+ p enables the pr_debug() callsite.
+ f Include the function name in the printed message
+ l Include line number in the printed message
+ m Include module name in the printed message
+ t Include thread ID in messages not generated from interrupt context
+ _ No flags are set. (Or'd with others on input)
+
+For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only ``p`` flag
+have meaning, other flags ignored.
+
+For display, the flags are preceded by ``=``
+(mnemonic: what the flags are currently equal to).
+
+Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification.
+To clear all flags at once, use ``=_`` or ``-flmpt``.
+
+
+Debug messages during Boot Process
+==================================
+
+To activate debug messages for core code and built-in modules during
+the boot process, even before userspace and debugfs exists, use
+``dyndbg="QUERY"``, ``module.dyndbg="QUERY"``, or ``ddebug_query="QUERY"``
+(``ddebug_query`` is obsoleted by ``dyndbg``, and deprecated). QUERY follows
+the syntax described above, but must not exceed 1023 characters. Your
+bootloader may impose lower limits.
+
+These ``dyndbg`` params are processed just after the ddebug tables are
+processed, as part of the arch_initcall. Thus you can enable debug
+messages in all code run after this arch_initcall via this boot
+parameter.
+
+On an x86 system for example ACPI enablement is a subsys_initcall and::
+
+ dyndbg="file ec.c +p"
+
+will show early Embedded Controller transactions during ACPI setup if
+your machine (typically a laptop) has an Embedded Controller.
+PCI (or other devices) initialization also is a hot candidate for using
+this boot parameter for debugging purposes.
+
+If ``foo`` module is not built-in, ``foo.dyndbg`` will still be processed at
+boot time, without effect, but will be reprocessed when module is
+loaded later. ``dyndbg_query=`` and bare ``dyndbg=`` are only processed at
+boot.
+
+
+Debug Messages at Module Initialization Time
+============================================
+
+When ``modprobe foo`` is called, modprobe scans ``/proc/cmdline`` for
+``foo.params``, strips ``foo.``, and passes them to the kernel along with
+params given in modprobe args or ``/etc/modprob.d/*.conf`` files,
+in the following order:
+
+1. parameters given via ``/etc/modprobe.d/*.conf``::
+
+ options foo dyndbg=+pt
+ options foo dyndbg # defaults to +p
+
+2. ``foo.dyndbg`` as given in boot args, ``foo.`` is stripped and passed::
+
+ foo.dyndbg=" func bar +p; func buz +mp"
+
+3. args to modprobe::
+
+ modprobe foo dyndbg==pmf # override previous settings
+
+These ``dyndbg`` queries are applied in order, with last having final say.
+This allows boot args to override or modify those from ``/etc/modprobe.d``
+(sensible, since 1 is system wide, 2 is kernel or boot specific), and
+modprobe args to override both.
+
+In the ``foo.dyndbg="QUERY"`` form, the query must exclude ``module foo``.
+``foo`` is extracted from the param-name, and applied to each query in
+``QUERY``, and only 1 match-spec of each type is allowed.
+
+The ``dyndbg`` option is a "fake" module parameter, which means:
+
+- modules do not need to define it explicitly
+- every module gets it tacitly, whether they use pr_debug or not
+- it doesn't appear in ``/sys/module/$module/parameters/``
+ To see it, grep the control file, or inspect ``/proc/cmdline.``
+
+For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or
+enabled by ``-DDEBUG`` flag during compilation) can be disabled later via
+the sysfs interface if the debug messages are no longer needed::
+
+ echo "module module_name -p" > <debugfs>/dynamic_debug/control
+
+Examples
+========
+
+::
+
+ // enable the message at line 1603 of file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all the messages in file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all the messages in the NFS server module
+ nullarbor:~ # echo -n 'module nfsd +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process +p' >
+ <debugfs>/dynamic_debug/control
+
+ // disable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process -p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
+ nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable messages in files of which the paths include string "usb"
+ nullarbor:~ # echo -n '*usb* +p' > <debugfs>/dynamic_debug/control
+
+ // enable all messages
+ nullarbor:~ # echo -n '+p' > <debugfs>/dynamic_debug/control
+
+ // add module, function to all enabled messages
+ nullarbor:~ # echo -n '+mf' > <debugfs>/dynamic_debug/control
+
+ // boot-args example, with newlines and comments for readability
+ Kernel command line: ...
+ // see whats going on in dyndbg=value processing
+ dynamic_debug.verbose=1
+ // enable pr_debugs in 2 builtins, #cmt is stripped
+ dyndbg="module params +p #cmt ; module sys +p"
+ // enable pr_debugs in 2 functions in a module loaded later
+ pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p"
--- /dev/null
+Linux Kernel User's Documentation
+=================================
+
+Contents:
+
+.. toctree::
+ :maxdepth: 2
+ :numbered:
+
+ README
+ reporting-bugs
+ bug-hunting
+ oops-tracing
+ ramoops
+ initrd
+ init
+ dynamic-debug-howto
+ security-bugs
+ kernel-parameters
+ serial-console
+ braille-console
+ parport
+ md
+ module-signing
+ sysrq
+ unicode
+ vga-softcursor
+ sysfs-rules
+ devices
+ binfmt-misc
+ mono
+ java
+ bad-memory
+ basic-profiling
--- /dev/null
+Explaining the dreaded "No init found." boot hang message
+=========================================================
+
+OK, so you've got this pretty unintuitive message (currently located
+in init/main.c) and are wondering what the H*** went wrong.
+Some high-level reasons for failure (listed roughly in order of execution)
+to load the init binary are:
+
+A) Unable to mount root FS
+B) init binary doesn't exist on rootfs
+C) broken console device
+D) binary exists but dependencies not available
+E) binary cannot be loaded
+
+Detailed explanations:
+
+A) Set "debug" kernel parameter (in bootloader config file or CONFIG_CMDLINE)
+ to get more detailed kernel messages.
+B) make sure you have the correct root FS type
+ (and ``root=`` kernel parameter points to the correct partition),
+ required drivers such as storage hardware (such as SCSI or USB!)
+ and filesystem (ext3, jffs2 etc.) are builtin (alternatively as modules,
+ to be pre-loaded by an initrd)
+C) Possibly a conflict in ``console= setup`` --> initial console unavailable.
+ E.g. some serial consoles are unreliable due to serial IRQ issues (e.g.
+ missing interrupt-based configuration).
+ Try using a different ``console= device`` or e.g. ``netconsole=``.
+D) e.g. required library dependencies of the init binary such as
+ ``/lib/ld-linux.so.2`` missing or broken. Use
+ ``readelf -d <INIT>|grep NEEDED`` to find out which libraries are required.
+E) make sure the binary's architecture matches your hardware.
+ E.g. i386 vs. x86_64 mismatch, or trying to load x86 on ARM hardware.
+ In case you tried loading a non-binary file here (shell script?),
+ you should make sure that the script specifies an interpreter in its shebang
+ header line (``#!/...``) that is fully working (including its library
+ dependencies). And before tackling scripts, better first test a simple
+ non-script binary such as ``/bin/sh`` and confirm its successful execution.
+ To find out more, add code ``to init/main.c`` to display kernel_execve()s
+ return values.
+
+Please extend this explanation whenever you find new failure causes
+(after all loading the init binary is a CRITICAL and hard transition step
+which needs to be made as painless as possible), then submit patch to LKML.
+Further TODOs:
+
+- Implement the various ``run_init_process()`` invocations via a struct array
+ which can then store the ``kernel_execve()`` result value and on failure
+ log it all by iterating over **all** results (very important usability fix).
+- try to make the implementation itself more helpful in general,
+ e.g. by providing additional error messages at affected places.
+
+Andreas Mohr <andi at lisas period de>
--- /dev/null
+Using the initial RAM disk (initrd)
+===================================
+
+Written 1996,2000 by Werner Almesberger <werner.almesberger@epfl.ch> and
+Hans Lermen <lermen@fgan.de>
+
+
+initrd provides the capability to load a RAM disk by the boot loader.
+This RAM disk can then be mounted as the root file system and programs
+can be run from it. Afterwards, a new root file system can be mounted
+from a different device. The previous root (from initrd) is then moved
+to a directory and can be subsequently unmounted.
+
+initrd is mainly designed to allow system startup to occur in two phases,
+where the kernel comes up with a minimum set of compiled-in drivers, and
+where additional modules are loaded from initrd.
+
+This document gives a brief overview of the use of initrd. A more detailed
+discussion of the boot process can be found in [#f1]_.
+
+
+Operation
+---------
+
+When using initrd, the system typically boots as follows:
+
+ 1) the boot loader loads the kernel and the initial RAM disk
+ 2) the kernel converts initrd into a "normal" RAM disk and
+ frees the memory used by initrd
+ 3) if the root device is not ``/dev/ram0``, the old (deprecated)
+ change_root procedure is followed. see the "Obsolete root change
+ mechanism" section below.
+ 4) root device is mounted. if it is ``/dev/ram0``, the initrd image is
+ then mounted as root
+ 5) /sbin/init is executed (this can be any valid executable, including
+ shell scripts; it is run with uid 0 and can do basically everything
+ init can do).
+ 6) init mounts the "real" root file system
+ 7) init places the root file system at the root directory using the
+ pivot_root system call
+ 8) init execs the ``/sbin/init`` on the new root filesystem, performing
+ the usual boot sequence
+ 9) the initrd file system is removed
+
+Note that changing the root directory does not involve unmounting it.
+It is therefore possible to leave processes running on initrd during that
+procedure. Also note that file systems mounted under initrd continue to
+be accessible.
+
+
+Boot command-line options
+-------------------------
+
+initrd adds the following new options::
+
+ initrd=<path> (e.g. LOADLIN)
+
+ Loads the specified file as the initial RAM disk. When using LILO, you
+ have to specify the RAM disk image file in /etc/lilo.conf, using the
+ INITRD configuration variable.
+
+ noinitrd
+
+ initrd data is preserved but it is not converted to a RAM disk and
+ the "normal" root file system is mounted. initrd data can be read
+ from /dev/initrd. Note that the data in initrd can have any structure
+ in this case and doesn't necessarily have to be a file system image.
+ This option is used mainly for debugging.
+
+ Note: /dev/initrd is read-only and it can only be used once. As soon
+ as the last process has closed it, all data is freed and /dev/initrd
+ can't be opened anymore.
+
+ root=/dev/ram0
+
+ initrd is mounted as root, and the normal boot procedure is followed,
+ with the RAM disk mounted as root.
+
+Compressed cpio images
+----------------------
+
+Recent kernels have support for populating a ramdisk from a compressed cpio
+archive. On such systems, the creation of a ramdisk image doesn't need to
+involve special block devices or loopbacks; you merely create a directory on
+disk with the desired initrd content, cd to that directory, and run (as an
+example)::
+
+ find . | cpio --quiet -H newc -o | gzip -9 -n > /boot/imagefile.img
+
+Examining the contents of an existing image file is just as simple::
+
+ mkdir /tmp/imagefile
+ cd /tmp/imagefile
+ gzip -cd /boot/imagefile.img | cpio -imd --quiet
+
+Installation
+------------
+
+First, a directory for the initrd file system has to be created on the
+"normal" root file system, e.g.::
+
+ # mkdir /initrd
+
+The name is not relevant. More details can be found on the
+:manpage:`pivot_root(2)` man page.
+
+If the root file system is created during the boot procedure (i.e. if
+you're building an install floppy), the root file system creation
+procedure should create the ``/initrd`` directory.
+
+If initrd will not be mounted in some cases, its content is still
+accessible if the following device has been created::
+
+ # mknod /dev/initrd b 1 250
+ # chmod 400 /dev/initrd
+
+Second, the kernel has to be compiled with RAM disk support and with
+support for the initial RAM disk enabled. Also, at least all components
+needed to execute programs from initrd (e.g. executable format and file
+system) must be compiled into the kernel.
+
+Third, you have to create the RAM disk image. This is done by creating a
+file system on a block device, copying files to it as needed, and then
+copying the content of the block device to the initrd file. With recent
+kernels, at least three types of devices are suitable for that:
+
+ - a floppy disk (works everywhere but it's painfully slow)
+ - a RAM disk (fast, but allocates physical memory)
+ - a loopback device (the most elegant solution)
+
+We'll describe the loopback device method:
+
+ 1) make sure loopback block devices are configured into the kernel
+ 2) create an empty file system of the appropriate size, e.g.::
+
+ # dd if=/dev/zero of=initrd bs=300k count=1
+ # mke2fs -F -m0 initrd
+
+ (if space is critical, you may want to use the Minix FS instead of Ext2)
+ 3) mount the file system, e.g.::
+
+ # mount -t ext2 -o loop initrd /mnt
+
+ 4) create the console device::
+
+ # mkdir /mnt/dev
+ # mknod /mnt/dev/console c 5 1
+
+ 5) copy all the files that are needed to properly use the initrd
+ environment. Don't forget the most important file, ``/sbin/init``
+
+ .. note:: ``/sbin/init`` permissions must include "x" (execute).
+
+ 6) correct operation the initrd environment can frequently be tested
+ even without rebooting with the command::
+
+ # chroot /mnt /sbin/init
+
+ This is of course limited to initrds that do not interfere with the
+ general system state (e.g. by reconfiguring network interfaces,
+ overwriting mounted devices, trying to start already running demons,
+ etc. Note however that it is usually possible to use pivot_root in
+ such a chroot'ed initrd environment.)
+ 7) unmount the file system::
+
+ # umount /mnt
+
+ 8) the initrd is now in the file "initrd". Optionally, it can now be
+ compressed::
+
+ # gzip -9 initrd
+
+For experimenting with initrd, you may want to take a rescue floppy and
+only add a symbolic link from ``/sbin/init`` to ``/bin/sh``. Alternatively, you
+can try the experimental newlib environment [#f2]_ to create a small
+initrd.
+
+Finally, you have to boot the kernel and load initrd. Almost all Linux
+boot loaders support initrd. Since the boot process is still compatible
+with an older mechanism, the following boot command line parameters
+have to be given::
+
+ root=/dev/ram0 rw
+
+(rw is only necessary if writing to the initrd file system.)
+
+With LOADLIN, you simply execute::
+
+ LOADLIN <kernel> initrd=<disk_image>
+
+e.g.::
+
+ LOADLIN C:\LINUX\BZIMAGE initrd=C:\LINUX\INITRD.GZ root=/dev/ram0 rw
+
+With LILO, you add the option ``INITRD=<path>`` to either the global section
+or to the section of the respective kernel in ``/etc/lilo.conf``, and pass
+the options using APPEND, e.g.::
+
+ image = /bzImage
+ initrd = /boot/initrd.gz
+ append = "root=/dev/ram0 rw"
+
+and run ``/sbin/lilo``
+
+For other boot loaders, please refer to the respective documentation.
+
+Now you can boot and enjoy using initrd.
+
+
+Changing the root device
+------------------------
+
+When finished with its duties, init typically changes the root device
+and proceeds with starting the Linux system on the "real" root device.
+
+The procedure involves the following steps:
+ - mounting the new root file system
+ - turning it into the root file system
+ - removing all accesses to the old (initrd) root file system
+ - unmounting the initrd file system and de-allocating the RAM disk
+
+Mounting the new root file system is easy: it just needs to be mounted on
+a directory under the current root. Example::
+
+ # mkdir /new-root
+ # mount -o ro /dev/hda1 /new-root
+
+The root change is accomplished with the pivot_root system call, which
+is also available via the ``pivot_root`` utility (see :manpage:`pivot_root(8)`
+man page; ``pivot_root`` is distributed with util-linux version 2.10h or higher
+[#f3]_). ``pivot_root`` moves the current root to a directory under the new
+root, and puts the new root at its place. The directory for the old root
+must exist before calling ``pivot_root``. Example::
+
+ # cd /new-root
+ # mkdir initrd
+ # pivot_root . initrd
+
+Now, the init process may still access the old root via its
+executable, shared libraries, standard input/output/error, and its
+current root directory. All these references are dropped by the
+following command::
+
+ # exec chroot . what-follows <dev/console >dev/console 2>&1
+
+Where what-follows is a program under the new root, e.g. ``/sbin/init``
+If the new root file system will be used with udev and has no valid
+``/dev`` directory, udev must be initialized before invoking chroot in order
+to provide ``/dev/console``.
+
+Note: implementation details of pivot_root may change with time. In order
+to ensure compatibility, the following points should be observed:
+
+ - before calling pivot_root, the current directory of the invoking
+ process should point to the new root directory
+ - use . as the first argument, and the _relative_ path of the directory
+ for the old root as the second argument
+ - a chroot program must be available under the old and the new root
+ - chroot to the new root afterwards
+ - use relative paths for dev/console in the exec command
+
+Now, the initrd can be unmounted and the memory allocated by the RAM
+disk can be freed::
+
+ # umount /initrd
+ # blockdev --flushbufs /dev/ram0
+
+It is also possible to use initrd with an NFS-mounted root, see the
+:manpage:`pivot_root(8)` man page for details.
+
+
+Usage scenarios
+---------------
+
+The main motivation for implementing initrd was to allow for modular
+kernel configuration at system installation. The procedure would work
+as follows:
+
+ 1) system boots from floppy or other media with a minimal kernel
+ (e.g. support for RAM disks, initrd, a.out, and the Ext2 FS) and
+ loads initrd
+ 2) ``/sbin/init`` determines what is needed to (1) mount the "real" root FS
+ (i.e. device type, device drivers, file system) and (2) the
+ distribution media (e.g. CD-ROM, network, tape, ...). This can be
+ done by asking the user, by auto-probing, or by using a hybrid
+ approach.
+ 3) ``/sbin/init`` loads the necessary kernel modules
+ 4) ``/sbin/init`` creates and populates the root file system (this doesn't
+ have to be a very usable system yet)
+ 5) ``/sbin/init`` invokes ``pivot_root`` to change the root file system and
+ execs - via chroot - a program that continues the installation
+ 6) the boot loader is installed
+ 7) the boot loader is configured to load an initrd with the set of
+ modules that was used to bring up the system (e.g. ``/initrd`` can be
+ modified, then unmounted, and finally, the image is written from
+ ``/dev/ram0`` or ``/dev/rd/0`` to a file)
+ 8) now the system is bootable and additional installation tasks can be
+ performed
+
+The key role of initrd here is to re-use the configuration data during
+normal system operation without requiring the use of a bloated "generic"
+kernel or re-compiling or re-linking the kernel.
+
+A second scenario is for installations where Linux runs on systems with
+different hardware configurations in a single administrative domain. In
+such cases, it is desirable to generate only a small set of kernels
+(ideally only one) and to keep the system-specific part of configuration
+information as small as possible. In this case, a common initrd could be
+generated with all the necessary modules. Then, only ``/sbin/init`` or a file
+read by it would have to be different.
+
+A third scenario is more convenient recovery disks, because information
+like the location of the root FS partition doesn't have to be provided at
+boot time, but the system loaded from initrd can invoke a user-friendly
+dialog and it can also perform some sanity checks (or even some form of
+auto-detection).
+
+Last not least, CD-ROM distributors may use it for better installation
+from CD, e.g. by using a boot floppy and bootstrapping a bigger RAM disk
+via initrd from CD; or by booting via a loader like ``LOADLIN`` or directly
+from the CD-ROM, and loading the RAM disk from CD without need of
+floppies.
+
+
+Obsolete root change mechanism
+------------------------------
+
+The following mechanism was used before the introduction of pivot_root.
+Current kernels still support it, but you should _not_ rely on its
+continued availability.
+
+It works by mounting the "real" root device (i.e. the one set with rdev
+in the kernel image or with root=... at the boot command line) as the
+root file system when linuxrc exits. The initrd file system is then
+unmounted, or, if it is still busy, moved to a directory ``/initrd``, if
+such a directory exists on the new root file system.
+
+In order to use this mechanism, you do not have to specify the boot
+command options root, init, or rw. (If specified, they will affect
+the real root file system, not the initrd environment.)
+
+If /proc is mounted, the "real" root device can be changed from within
+linuxrc by writing the number of the new root FS device to the special
+file /proc/sys/kernel/real-root-dev, e.g.::
+
+ # echo 0x301 >/proc/sys/kernel/real-root-dev
+
+Note that the mechanism is incompatible with NFS and similar file
+systems.
+
+This old, deprecated mechanism is commonly called ``change_root``, while
+the new, supported mechanism is called ``pivot_root``.
+
+
+Mixed change_root and pivot_root mechanism
+------------------------------------------
+
+In case you did not want to use ``root=/dev/ram0`` to trigger the pivot_root
+mechanism, you may create both ``/linuxrc`` and ``/sbin/init`` in your initrd
+image.
+
+``/linuxrc`` would contain only the following::
+
+ #! /bin/sh
+ mount -n -t proc proc /proc
+ echo 0x0100 >/proc/sys/kernel/real-root-dev
+ umount -n /proc
+
+Once linuxrc exited, the kernel would mount again your initrd as root,
+this time executing ``/sbin/init``. Again, it would be the duty of this init
+to build the right environment (maybe using the ``root= device`` passed on
+the cmdline) before the final execution of the real ``/sbin/init``.
+
+
+Resources
+---------
+
+.. [#f1] Almesberger, Werner; "Booting Linux: The History and the Future"
+ http://www.almesberger.net/cv/papers/ols2k-9.ps.gz
+.. [#f2] newlib package (experimental), with initrd example
+ https://www.sourceware.org/newlib/
+.. [#f3] util-linux: Miscellaneous utilities for Linux
+ https://www.kernel.org/pub/linux/utils/util-linux/
--- /dev/null
+Java(tm) Binary Kernel Support for Linux v1.03
+----------------------------------------------
+
+Linux beats them ALL! While all other OS's are TALKING about direct
+support of Java Binaries in the OS, Linux is doing it!
+
+You can execute Java applications and Java Applets just like any
+other program after you have done the following:
+
+1) You MUST FIRST install the Java Developers Kit for Linux.
+ The Java on Linux HOWTO gives the details on getting and
+ installing this. This HOWTO can be found at:
+
+ ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/Java-HOWTO
+
+ You should also set up a reasonable CLASSPATH environment
+ variable to use Java applications that make use of any
+ nonstandard classes (not included in the same directory
+ as the application itself).
+
+2) You have to compile BINFMT_MISC either as a module or into
+ the kernel (``CONFIG_BINFMT_MISC``) and set it up properly.
+ If you choose to compile it as a module, you will have
+ to insert it manually with modprobe/insmod, as kmod
+ cannot easily be supported with binfmt_misc.
+ Read the file 'binfmt_misc.txt' in this directory to know
+ more about the configuration process.
+
+3) Add the following configuration items to binfmt_misc
+ (you should really have read ``binfmt_misc.txt`` now):
+ support for Java applications::
+
+ ':Java:M::\xca\xfe\xba\xbe::/usr/local/bin/javawrapper:'
+
+ support for executable Jar files::
+
+ ':ExecutableJAR:E::jar::/usr/local/bin/jarwrapper:'
+
+ support for Java Applets::
+
+ ':Applet:E::html::/usr/bin/appletviewer:'
+
+ or the following, if you want to be more selective::
+
+ ':Applet:M::<!--applet::/usr/bin/appletviewer:'
+
+ Of course you have to fix the path names. The path/file names given in this
+ document match the Debian 2.1 system. (i.e. jdk installed in ``/usr``,
+ custom wrappers from this document in ``/usr/local``)
+
+ Note, that for the more selective applet support you have to modify
+ existing html-files to contain ``<!--applet-->`` in the first line
+ (``<`` has to be the first character!) to let this work!
+
+ For the compiled Java programs you need a wrapper script like the
+ following (this is because Java is broken in case of the filename
+ handling), again fix the path names, both in the script and in the
+ above given configuration string.
+
+ You, too, need the little program after the script. Compile like::
+
+ gcc -O2 -o javaclassname javaclassname.c
+
+ and stick it to ``/usr/local/bin``.
+
+ Both the javawrapper shellscript and the javaclassname program
+ were supplied by Colin J. Watson <cjw44@cam.ac.uk>.
+
+Javawrapper shell script::
+
+ #!/bin/bash
+ # /usr/local/bin/javawrapper - the wrapper for binfmt_misc/java
+
+ if [ -z "$1" ]; then
+ exec 1>&2
+ echo Usage: $0 class-file
+ exit 1
+ fi
+
+ CLASS=$1
+ FQCLASS=`/usr/local/bin/javaclassname $1`
+ FQCLASSN=`echo $FQCLASS | sed -e 's/^.*\.\([^.]*\)$/\1/'`
+ FQCLASSP=`echo $FQCLASS | sed -e 's-\.-/-g' -e 's-^[^/]*$--' -e 's-/[^/]*$--'`
+
+ # for example:
+ # CLASS=Test.class
+ # FQCLASS=foo.bar.Test
+ # FQCLASSN=Test
+ # FQCLASSP=foo/bar
+
+ unset CLASSBASE
+
+ declare -i LINKLEVEL=0
+
+ while :; do
+ if [ "`basename $CLASS .class`" == "$FQCLASSN" ]; then
+ # See if this directory works straight off
+ cd -L `dirname $CLASS`
+ CLASSDIR=$PWD
+ cd $OLDPWD
+ if echo $CLASSDIR | grep -q "$FQCLASSP$"; then
+ CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."`
+ break;
+ fi
+ # Try dereferencing the directory name
+ cd -P `dirname $CLASS`
+ CLASSDIR=$PWD
+ cd $OLDPWD
+ if echo $CLASSDIR | grep -q "$FQCLASSP$"; then
+ CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."`
+ break;
+ fi
+ # If no other possible filename exists
+ if [ ! -L $CLASS ]; then
+ exec 1>&2
+ echo $0:
+ echo " $CLASS should be in a" \
+ "directory tree called $FQCLASSP"
+ exit 1
+ fi
+ fi
+ if [ ! -L $CLASS ]; then break; fi
+ # Go down one more level of symbolic links
+ let LINKLEVEL+=1
+ if [ $LINKLEVEL -gt 5 ]; then
+ exec 1>&2
+ echo $0:
+ echo " Too many symbolic links encountered"
+ exit 1
+ fi
+ CLASS=`ls --color=no -l $CLASS | sed -e 's/^.* \([^ ]*\)$/\1/'`
+ done
+
+ if [ -z "$CLASSBASE" ]; then
+ if [ -z "$FQCLASSP" ]; then
+ GOODNAME=$FQCLASSN.class
+ else
+ GOODNAME=$FQCLASSP/$FQCLASSN.class
+ fi
+ exec 1>&2
+ echo $0:
+ echo " $FQCLASS should be in a file called $GOODNAME"
+ exit 1
+ fi
+
+ if ! echo $CLASSPATH | grep -q "^\(.*:\)*$CLASSBASE\(:.*\)*"; then
+ # class is not in CLASSPATH, so prepend dir of class to CLASSPATH
+ if [ -z "${CLASSPATH}" ] ; then
+ export CLASSPATH=$CLASSBASE
+ else
+ export CLASSPATH=$CLASSBASE:$CLASSPATH
+ fi
+ fi
+
+ shift
+ /usr/bin/java $FQCLASS "$@"
+
+javaclassname.c::
+
+ /* javaclassname.c
+ *
+ * Extracts the class name from a Java class file; intended for use in a Java
+ * wrapper of the type supported by the binfmt_misc option in the Linux kernel.
+ *
+ * Copyright (C) 1999 Colin J. Watson <cjw44@cam.ac.uk>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+ #include <stdlib.h>
+ #include <stdio.h>
+ #include <stdarg.h>
+ #include <sys/types.h>
+
+ /* From Sun's Java VM Specification, as tag entries in the constant pool. */
+
+ #define CP_UTF8 1
+ #define CP_INTEGER 3
+ #define CP_FLOAT 4
+ #define CP_LONG 5
+ #define CP_DOUBLE 6
+ #define CP_CLASS 7
+ #define CP_STRING 8
+ #define CP_FIELDREF 9
+ #define CP_METHODREF 10
+ #define CP_INTERFACEMETHODREF 11
+ #define CP_NAMEANDTYPE 12
+ #define CP_METHODHANDLE 15
+ #define CP_METHODTYPE 16
+ #define CP_INVOKEDYNAMIC 18
+
+ /* Define some commonly used error messages */
+
+ #define seek_error() error("%s: Cannot seek\n", program)
+ #define corrupt_error() error("%s: Class file corrupt\n", program)
+ #define eof_error() error("%s: Unexpected end of file\n", program)
+ #define utf8_error() error("%s: Only ASCII 1-255 supported\n", program);
+
+ char *program;
+
+ long *pool;
+
+ u_int8_t read_8(FILE *classfile);
+ u_int16_t read_16(FILE *classfile);
+ void skip_constant(FILE *classfile, u_int16_t *cur);
+ void error(const char *format, ...);
+ int main(int argc, char **argv);
+
+ /* Reads in an unsigned 8-bit integer. */
+ u_int8_t read_8(FILE *classfile)
+ {
+ int b = fgetc(classfile);
+ if(b == EOF)
+ eof_error();
+ return (u_int8_t)b;
+ }
+
+ /* Reads in an unsigned 16-bit integer. */
+ u_int16_t read_16(FILE *classfile)
+ {
+ int b1, b2;
+ b1 = fgetc(classfile);
+ if(b1 == EOF)
+ eof_error();
+ b2 = fgetc(classfile);
+ if(b2 == EOF)
+ eof_error();
+ return (u_int16_t)((b1 << 8) | b2);
+ }
+
+ /* Reads in a value from the constant pool. */
+ void skip_constant(FILE *classfile, u_int16_t *cur)
+ {
+ u_int16_t len;
+ int seekerr = 1;
+ pool[*cur] = ftell(classfile);
+ switch(read_8(classfile))
+ {
+ case CP_UTF8:
+ len = read_16(classfile);
+ seekerr = fseek(classfile, len, SEEK_CUR);
+ break;
+ case CP_CLASS:
+ case CP_STRING:
+ case CP_METHODTYPE:
+ seekerr = fseek(classfile, 2, SEEK_CUR);
+ break;
+ case CP_METHODHANDLE:
+ seekerr = fseek(classfile, 3, SEEK_CUR);
+ break;
+ case CP_INTEGER:
+ case CP_FLOAT:
+ case CP_FIELDREF:
+ case CP_METHODREF:
+ case CP_INTERFACEMETHODREF:
+ case CP_NAMEANDTYPE:
+ case CP_INVOKEDYNAMIC:
+ seekerr = fseek(classfile, 4, SEEK_CUR);
+ break;
+ case CP_LONG:
+ case CP_DOUBLE:
+ seekerr = fseek(classfile, 8, SEEK_CUR);
+ ++(*cur);
+ break;
+ default:
+ corrupt_error();
+ }
+ if(seekerr)
+ seek_error();
+ }
+
+ void error(const char *format, ...)
+ {
+ va_list ap;
+ va_start(ap, format);
+ vfprintf(stderr, format, ap);
+ va_end(ap);
+ exit(1);
+ }
+
+ int main(int argc, char **argv)
+ {
+ FILE *classfile;
+ u_int16_t cp_count, i, this_class, classinfo_ptr;
+ u_int8_t length;
+
+ program = argv[0];
+
+ if(!argv[1])
+ error("%s: Missing input file\n", program);
+ classfile = fopen(argv[1], "rb");
+ if(!classfile)
+ error("%s: Error opening %s\n", program, argv[1]);
+
+ if(fseek(classfile, 8, SEEK_SET)) /* skip magic and version numbers */
+ seek_error();
+ cp_count = read_16(classfile);
+ pool = calloc(cp_count, sizeof(long));
+ if(!pool)
+ error("%s: Out of memory for constant pool\n", program);
+
+ for(i = 1; i < cp_count; ++i)
+ skip_constant(classfile, &i);
+ if(fseek(classfile, 2, SEEK_CUR)) /* skip access flags */
+ seek_error();
+
+ this_class = read_16(classfile);
+ if(this_class < 1 || this_class >= cp_count)
+ corrupt_error();
+ if(!pool[this_class] || pool[this_class] == -1)
+ corrupt_error();
+ if(fseek(classfile, pool[this_class] + 1, SEEK_SET))
+ seek_error();
+
+ classinfo_ptr = read_16(classfile);
+ if(classinfo_ptr < 1 || classinfo_ptr >= cp_count)
+ corrupt_error();
+ if(!pool[classinfo_ptr] || pool[classinfo_ptr] == -1)
+ corrupt_error();
+ if(fseek(classfile, pool[classinfo_ptr] + 1, SEEK_SET))
+ seek_error();
+
+ length = read_16(classfile);
+ for(i = 0; i < length; ++i)
+ {
+ u_int8_t x = read_8(classfile);
+ if((x & 0x80) || !x)
+ {
+ if((x & 0xE0) == 0xC0)
+ {
+ u_int8_t y = read_8(classfile);
+ if((y & 0xC0) == 0x80)
+ {
+ int c = ((x & 0x1f) << 6) + (y & 0x3f);
+ if(c) putchar(c);
+ else utf8_error();
+ }
+ else utf8_error();
+ }
+ else utf8_error();
+ }
+ else if(x == '/') putchar('.');
+ else putchar(x);
+ }
+ putchar('\n');
+ free(pool);
+ fclose(classfile);
+ return 0;
+ }
+
+jarwrapper::
+
+ #!/bin/bash
+ # /usr/local/java/bin/jarwrapper - the wrapper for binfmt_misc/jar
+
+ java -jar $1
+
+
+Now simply ``chmod +x`` the ``.class``, ``.jar`` and/or ``.html`` files you
+want to execute.
+
+To add a Java program to your path best put a symbolic link to the main
+.class file into /usr/bin (or another place you like) omitting the .class
+extension. The directory containing the original .class file will be
+added to your CLASSPATH during execution.
+
+
+To test your new setup, enter in the following simple Java app, and name
+it "HelloWorld.java"::
+
+ class HelloWorld {
+ public static void main(String args[]) {
+ System.out.println("Hello World!");
+ }
+ }
+
+Now compile the application with::
+
+ javac HelloWorld.java
+
+Set the executable permissions of the binary file, with::
+
+ chmod 755 HelloWorld.class
+
+And then execute it::
+
+ ./HelloWorld.class
+
+
+To execute Java Jar files, simple chmod the ``*.jar`` files to include
+the execution bit, then just do::
+
+ ./Application.jar
+
+
+To execute Java Applets, simple chmod the ``*.html`` files to include
+the execution bit, then just do::
+
+ ./Applet.html
+
+
+originally by Brian A. Lantz, brian@lantz.com
+heavily edited for binfmt_misc by Richard Günther
+new scripts by Colin J. Watson <cjw44@cam.ac.uk>
+added executable Jar file support by Kurt Huwig <kurt@iku-netz.de>
--- /dev/null
+Kernel Parameters
+~~~~~~~~~~~~~~~~~
+
+The following is a consolidated list of the kernel parameters as
+implemented by the __setup(), core_param() and module_param() macros
+and sorted into English Dictionary order (defined as ignoring all
+punctuation and sorting digits before letters in a case insensitive
+manner), and with descriptions where known.
+
+The kernel parses parameters from the kernel command line up to "--";
+if it doesn't recognize a parameter and it doesn't contain a '.', the
+parameter gets passed to init: parameters with '=' go into init's
+environment, others are passed as command line arguments to init.
+Everything after "--" is passed as an argument to init.
+
+Module parameters can be specified in two ways: via the kernel command
+line with a module name prefix, or via modprobe, e.g.::
+
+ (kernel command line) usbcore.blinkenlights=1
+ (modprobe command line) modprobe usbcore blinkenlights=1
+
+Parameters for modules which are built into the kernel need to be
+specified on the kernel command line. modprobe looks through the
+kernel command line (/proc/cmdline) and collects module parameters
+when it loads a module, so the kernel command line can be used for
+loadable modules too.
+
+Hyphens (dashes) and underscores are equivalent in parameter names, so::
+
+ log_buf_len=1M print-fatal-signals=1
+
+can also be entered as::
+
+ log-buf-len=1M print_fatal_signals=1
+
+Double-quotes can be used to protect spaces in values, e.g.::
+
+ param="spaces in here"
+
+cpu lists:
+----------
+
+Some kernel parameters take a list of CPUs as a value, e.g. isolcpus,
+nohz_full, irqaffinity, rcu_nocbs. The format of this list is:
+
+ <cpu number>,...,<cpu number>
+
+or
+
+ <cpu number>-<cpu number>
+ (must be a positive range in ascending order)
+
+or a mixture
+
+<cpu number>,...,<cpu number>-<cpu number>
+
+Note that for the special case of a range one can split the range into equal
+sized groups and for each group use some amount from the beginning of that
+group:
+
+ <cpu number>-cpu number>:<used size>/<group size>
+
+For example one can add to the command line following parameter:
+
+ isolcpus=1,2,10-20,100-2000:2/25
+
+where the final item represents CPUs 100,101,125,126,150,151,...
+
+
+
+This document may not be entirely up to date and comprehensive. The command
+"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
+module. Loadable modules, after being loaded into the running kernel, also
+reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
+parameters may be changed at runtime by the command
+``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``.
+
+The parameters listed below are only valid if certain kernel build options were
+enabled and if respective hardware is present. The text in square brackets at
+the beginning of each description states the restrictions within which a
+parameter is applicable::
+
+ ACPI ACPI support is enabled.
+ AGP AGP (Accelerated Graphics Port) is enabled.
+ ALSA ALSA sound support is enabled.
+ APIC APIC support is enabled.
+ APM Advanced Power Management support is enabled.
+ ARM ARM architecture is enabled.
+ AVR32 AVR32 architecture is enabled.
+ AX25 Appropriate AX.25 support is enabled.
+ BLACKFIN Blackfin architecture is enabled.
+ CLK Common clock infrastructure is enabled.
+ CMA Contiguous Memory Area support is enabled.
+ DRM Direct Rendering Management support is enabled.
+ DYNAMIC_DEBUG Build in debug messages and enable them at runtime
+ EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
+ EFI EFI Partitioning (GPT) is enabled
+ EIDE EIDE/ATAPI support is enabled.
+ EVM Extended Verification Module
+ FB The frame buffer device is enabled.
+ FTRACE Function tracing enabled.
+ GCOV GCOV profiling is enabled.
+ HW Appropriate hardware is enabled.
+ IA-64 IA-64 architecture is enabled.
+ IMA Integrity measurement architecture is enabled.
+ IOSCHED More than one I/O scheduler is enabled.
+ IP_PNP IP DHCP, BOOTP, or RARP is enabled.
+ IPV6 IPv6 support is enabled.
+ ISAPNP ISA PnP code is enabled.
+ ISDN Appropriate ISDN support is enabled.
+ JOY Appropriate joystick support is enabled.
+ KGDB Kernel debugger support is enabled.
+ KVM Kernel Virtual Machine support is enabled.
+ LIBATA Libata driver is enabled
+ LP Printer support is enabled.
+ LOOP Loopback device support is enabled.
+ M68k M68k architecture is enabled.
+ These options have more detailed description inside of
+ Documentation/m68k/kernel-options.txt.
+ MDA MDA console support is enabled.
+ MIPS MIPS architecture is enabled.
+ MOUSE Appropriate mouse support is enabled.
+ MSI Message Signaled Interrupts (PCI).
+ MTD MTD (Memory Technology Device) support is enabled.
+ NET Appropriate network support is enabled.
+ NUMA NUMA support is enabled.
+ NFS Appropriate NFS support is enabled.
+ OSS OSS sound support is enabled.
+ PV_OPS A paravirtualized kernel is enabled.
+ PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
+ PARISC The PA-RISC architecture is enabled.
+ PCI PCI bus support is enabled.
+ PCIE PCI Express support is enabled.
+ PCMCIA The PCMCIA subsystem is enabled.
+ PNP Plug & Play support is enabled.
+ PPC PowerPC architecture is enabled.
+ PPT Parallel port support is enabled.
+ PS2 Appropriate PS/2 support is enabled.
+ RAM RAM disk support is enabled.
+ S390 S390 architecture is enabled.
+ SCSI Appropriate SCSI support is enabled.
+ A lot of drivers have their options described inside
+ the Documentation/scsi/ sub-directory.
+ SECURITY Different security models are enabled.
+ SELINUX SELinux support is enabled.
+ APPARMOR AppArmor support is enabled.
+ SERIAL Serial support is enabled.
+ SH SuperH architecture is enabled.
+ SMP The kernel is an SMP kernel.
+ SPARC Sparc architecture is enabled.
+ SWSUSP Software suspend (hibernation) is enabled.
+ SUSPEND System suspend states are enabled.
+ TPM TPM drivers are enabled.
+ TS Appropriate touchscreen support is enabled.
+ UMS USB Mass Storage support is enabled.
+ USB USB support is enabled.
+ USBHID USB Human Interface Device support is enabled.
+ V4L Video For Linux support is enabled.
+ VMMIO Driver for memory mapped virtio devices is enabled.
+ VGA The VGA console has been enabled.
+ VT Virtual terminal support is enabled.
+ WDT Watchdog support is enabled.
+ XT IBM PC/XT MFM hard disk support is enabled.
+ X86-32 X86-32, aka i386 architecture is enabled.
+ X86-64 X86-64 architecture is enabled.
+ More X86-64 boot options can be found in
+ Documentation/x86/x86_64/boot-options.txt .
+ X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
+ X86_UV SGI UV support is enabled.
+ XEN Xen support is enabled
+
+In addition, the following text indicates that the option::
+
+ BUGS= Relates to possible processor bugs on the said processor.
+ KNL Is a kernel start-up parameter.
+ BOOT Is a boot loader parameter.
+
+Parameters denoted with BOOT are actually interpreted by the boot
+loader, and have no meaning to the kernel directly.
+Do not modify the syntax of boot loader parameters without extreme
+need or coordination with <Documentation/x86/boot.txt>.
+
+There are also arch-specific kernel-parameters not documented here.
+See for example <Documentation/x86/x86_64/boot-options.txt>.
+
+Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
+a trailing = on the name of any parameter states that that parameter will
+be entered as an environment variable, whereas its absence indicates that
+it will appear as a kernel argument readable via /proc/cmdline by programs
+running once the system is up.
+
+The number of kernel parameters is not limited, but the length of the
+complete command line (parameters including spaces etc.) is limited to
+a fixed number of characters. This limit depends on the architecture
+and is between 256 and 4096 characters. It is defined in the file
+./include/asm/setup.h as COMMAND_LINE_SIZE.
+
+Finally, the [KMG] suffix is commonly described after a number of kernel
+parameter values. These 'K', 'M', and 'G' letters represent the _binary_
+multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
+bytes respectively. Such letter suffixes can also be entirely omitted::
+
+
+ acpi= [HW,ACPI,X86,ARM64]
+ Advanced Configuration and Power Interface
+ Format: { force | on | off | strict | noirq | rsdt |
+ copy_dsdt }
+ force -- enable ACPI if default was off
+ on -- enable ACPI but allow fallback to DT [arm64]
+ off -- disable ACPI if default was on
+ noirq -- do not use ACPI for IRQ routing
+ strict -- Be less tolerant of platforms that are not
+ strictly ACPI specification compliant.
+ rsdt -- prefer RSDT over (default) XSDT
+ copy_dsdt -- copy DSDT to memory
+ For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force"
+ are available
+
+ See also Documentation/power/runtime_pm.txt, pci=noacpi
+
+ acpi_apic_instance= [ACPI, IOAPIC]
+ Format: <int>
+ 2: use 2nd APIC table, if available
+ 1,0: use 1st APIC table
+ default: 0
+
+ acpi_backlight= [HW,ACPI]
+ acpi_backlight=vendor
+ acpi_backlight=video
+ If set to vendor, prefer vendor specific driver
+ (e.g. thinkpad_acpi, sony_acpi, etc.) instead
+ of the ACPI video.ko driver.
+
+ acpi_force_32bit_fadt_addr
+ force FADT to use 32 bit addresses rather than the
+ 64 bit X_* addresses. Some firmware have broken 64
+ bit addresses for force ACPI ignore these and use
+ the older legacy 32 bit addresses.
+
+ acpica_no_return_repair [HW, ACPI]
+ Disable AML predefined validation mechanism
+ This mechanism can repair the evaluation result to make
+ the return objects more ACPI specification compliant.
+ This option is useful for developers to identify the
+ root cause of an AML interpreter issue when the issue
+ has something to do with the repair mechanism.
+
+ acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
+ acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
+ Format: <int>
+ CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
+ debug output. Bits in debug_layer correspond to a
+ _COMPONENT in an ACPI source file, e.g.,
+ #define _COMPONENT ACPI_PCI_COMPONENT
+ Bits in debug_level correspond to a level in
+ ACPI_DEBUG_PRINT statements, e.g.,
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
+ The debug_level mask defaults to "info". See
+ Documentation/acpi/debug.txt for more information about
+ debug layers and levels.
+
+ Enable processor driver info messages:
+ acpi.debug_layer=0x20000000
+ Enable PCI/PCI interrupt routing info messages:
+ acpi.debug_layer=0x400000
+ Enable AML "Debug" output, i.e., stores to the Debug
+ object while interpreting AML:
+ acpi.debug_layer=0xffffffff acpi.debug_level=0x2
+ Enable all messages related to ACPI hardware:
+ acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
+
+ Some values produce so much output that the system is
+ unusable. The "log_buf_len" parameter may be useful
+ if you need to capture more output.
+
+ acpi_enforce_resources= [ACPI]
+ { strict | lax | no }
+ Check for resource conflicts between native drivers
+ and ACPI OperationRegions (SystemIO and SystemMemory
+ only). IO ports and memory declared in ACPI might be
+ used by the ACPI subsystem in arbitrary AML code and
+ can interfere with legacy drivers.
+ strict (default): access to resources claimed by ACPI
+ is denied; legacy drivers trying to access reserved
+ resources will fail to bind to device using them.
+ lax: access to resources claimed by ACPI is allowed;
+ legacy drivers trying to access reserved resources
+ will bind successfully but a warning message is logged.
+ no: ACPI OperationRegions are not marked as reserved,
+ no further checks are performed.
+
+ acpi_force_table_verification [HW,ACPI]
+ Enable table checksum verification during early stage.
+ By default, this is disabled due to x86 early mapping
+ size limitation.
+
+ acpi_irq_balance [HW,ACPI]
+ ACPI will balance active IRQs
+ default in APIC mode
+
+ acpi_irq_nobalance [HW,ACPI]
+ ACPI will not move active IRQs (default)
+ default in PIC mode
+
+ acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
+ Format: <irq>,<irq>...
+
+ acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
+ use by PCI
+ Format: <irq>,<irq>...
+
+ acpi_no_auto_serialize [HW,ACPI]
+ Disable auto-serialization of AML methods
+ AML control methods that contain the opcodes to create
+ named objects will be marked as "Serialized" by the
+ auto-serialization feature.
+ This feature is enabled by default.
+ This option allows to turn off the feature.
+
+ acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
+ kernels.
+
+ acpi_no_static_ssdt [HW,ACPI]
+ Disable installation of static SSDTs at early boot time
+ By default, SSDTs contained in the RSDT/XSDT will be
+ installed automatically and they will appear under
+ /sys/firmware/acpi/tables.
+ This option turns off this feature.
+ Note that specifying this option does not affect
+ dynamic table installation which will install SSDT
+ tables to /sys/firmware/acpi/tables/dynamic.
+
+ acpi_rsdp= [ACPI,EFI,KEXEC]
+ Pass the RSDP address to the kernel, mostly used
+ on machines running EFI runtime service to boot the
+ second kernel for kdump.
+
+ acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
+ Format: To spoof as Windows 98: ="Microsoft Windows"
+
+ acpi_rev_override [ACPI] Override the _REV object to return 5 (instead
+ of 2 which is mandated by ACPI 6) as the supported ACPI
+ specification revision (when using this switch, it may
+ be necessary to carry out a cold reboot _twice_ in a
+ row to make it take effect on the platform firmware).
+
+ acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
+ acpi_osi="string1" # add string1
+ acpi_osi="!string2" # remove string2
+ acpi_osi=!* # remove all strings
+ acpi_osi=! # disable all built-in OS vendor
+ strings
+ acpi_osi=!! # enable all built-in OS vendor
+ strings
+ acpi_osi= # disable all strings
+
+ 'acpi_osi=!' can be used in combination with single or
+ multiple 'acpi_osi="string1"' to support specific OS
+ vendor string(s). Note that such command can only
+ affect the default state of the OS vendor strings, thus
+ it cannot affect the default state of the feature group
+ strings and the current state of the OS vendor strings,
+ specifying it multiple times through kernel command line
+ is meaningless. This command is useful when one do not
+ care about the state of the feature group strings which
+ should be controlled by the OSPM.
+ Examples:
+ 1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
+ to 'acpi_osi="Windows 2000" acpi_osi=!', they all
+ can make '_OSI("Windows 2000")' TRUE.
+
+ 'acpi_osi=' cannot be used in combination with other
+ 'acpi_osi=' command lines, the _OSI method will not
+ exist in the ACPI namespace. NOTE that such command can
+ only affect the _OSI support state, thus specifying it
+ multiple times through kernel command line is also
+ meaningless.
+ Examples:
+ 1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
+ FALSE.
+
+ 'acpi_osi=!*' can be used in combination with single or
+ multiple 'acpi_osi="string1"' to support specific
+ string(s). Note that such command can affect the
+ current state of both the OS vendor strings and the
+ feature group strings, thus specifying it multiple times
+ through kernel command line is meaningful. But it may
+ still not able to affect the final state of a string if
+ there are quirks related to this string. This command
+ is useful when one want to control the state of the
+ feature group strings to debug BIOS issues related to
+ the OSPM features.
+ Examples:
+ 1. 'acpi_osi="Module Device" acpi_osi=!*' can make
+ '_OSI("Module Device")' FALSE.
+ 2. 'acpi_osi=!* acpi_osi="Module Device"' can make
+ '_OSI("Module Device")' TRUE.
+ 3. 'acpi_osi=! acpi_osi=!* acpi_osi="Windows 2000"' is
+ equivalent to
+ 'acpi_osi=!* acpi_osi=! acpi_osi="Windows 2000"'
+ and
+ 'acpi_osi=!* acpi_osi="Windows 2000" acpi_osi=!',
+ they all will make '_OSI("Windows 2000")' TRUE.
+
+ acpi_pm_good [X86]
+ Override the pmtimer bug detection: force the kernel
+ to assume that this machine's pmtimer latches its value
+ and always returns good values.
+
+ acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
+ Format: { level | edge | high | low }
+
+ acpi_skip_timer_override [HW,ACPI]
+ Recognize and ignore IRQ0/pin2 Interrupt Override.
+ For broken nForce2 BIOS resulting in XT-PIC timer.
+
+ acpi_sleep= [HW,ACPI] Sleep options
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
+ old_ordering, nonvs, sci_force_enable }
+ See Documentation/power/video.txt for information on
+ s3_bios and s3_mode.
+ s3_beep is for debugging; it makes the PC's speaker beep
+ as soon as the kernel's real-mode entry point is called.
+ s4_nohwsig prevents ACPI hardware signature from being
+ used during resume from hibernation.
+ old_ordering causes the ACPI 1.0 ordering of the _PTS
+ control method, with respect to putting devices into
+ low power states, to be enforced (the ACPI 2.0 ordering
+ of _PTS is used by default).
+ nonvs prevents the kernel from saving/restoring the
+ ACPI NVS memory during suspend/hibernation and resume.
+ sci_force_enable causes the kernel to set SCI_EN directly
+ on resume from S1/S3 (which is against the ACPI spec,
+ but some broken systems don't work without it).
+
+ acpi_use_timer_override [HW,ACPI]
+ Use timer override. For some broken Nvidia NF5 boards
+ that require a timer override, but don't have HPET
+
+ add_efi_memmap [EFI; X86] Include EFI memory map in
+ kernel's map of available physical RAM.
+
+ agp= [AGP]
+ { off | try_unsupported }
+ off: disable AGP support
+ try_unsupported: try to drive unsupported chipsets
+ (may crash computer or cause data corruption)
+
+ ALSA [HW,ALSA]
+ See Documentation/sound/alsa/alsa-parameters.txt
+
+ alignment= [KNL,ARM]
+ Allow the default userspace alignment fault handler
+ behaviour to be specified. Bit 0 enables warnings,
+ bit 1 enables fixups, and bit 2 sends a segfault.
+
+ align_va_addr= [X86-64]
+ Align virtual addresses by clearing slice [14:12] when
+ allocating a VMA at process creation time. This option
+ gives you up to 3% performance improvement on AMD F15h
+ machines (where it is enabled by default) for a
+ CPU-intensive style benchmark, and it can vary highly in
+ a microbenchmark depending on workload and compiler.
+
+ 32: only for 32-bit processes
+ 64: only for 64-bit processes
+ on: enable for both 32- and 64-bit processes
+ off: disable for both 32- and 64-bit processes
+
+ alloc_snapshot [FTRACE]
+ Allocate the ftrace snapshot buffer on boot up when the
+ main buffer is allocated. This is handy if debugging
+ and you need to use tracing_snapshot() on boot up, and
+ do not want to use tracing_snapshot_alloc() as it needs
+ to be done where GFP_KERNEL allocations are allowed.
+
+ amd_iommu= [HW,X86-64]
+ Pass parameters to the AMD IOMMU driver in the system.
+ Possible values are:
+ fullflush - enable flushing of IO/TLB entries when
+ they are unmapped. Otherwise they are
+ flushed before they will be reused, which
+ is a lot of faster
+ off - do not initialize any AMD IOMMU found in
+ the system
+ force_isolation - Force device isolation for all
+ devices. The IOMMU driver is not
+ allowed anymore to lift isolation
+ requirements as needed. This option
+ does not override iommu=pt
+
+ amd_iommu_dump= [HW,X86-64]
+ Enable AMD IOMMU driver option to dump the ACPI table
+ for AMD IOMMU. With this option enabled, AMD IOMMU
+ driver will print ACPI tables for AMD IOMMU during
+ IOMMU initialization.
+
+ amd_iommu_intr= [HW,X86-64]
+ Specifies one of the following AMD IOMMU interrupt
+ remapping modes:
+ legacy - Use legacy interrupt remapping mode.
+ vapic - Use virtual APIC mode, which allows IOMMU
+ to inject interrupts directly into guest.
+ This mode requires kvm-amd.avic=1.
+ (Default when IOMMU HW support is present.)
+
+ amijoy.map= [HW,JOY] Amiga joystick support
+ Map of devices attached to JOY0DAT and JOY1DAT
+ Format: <a>,<b>
+ See also Documentation/input/joystick.txt
+
+ analog.map= [HW,JOY] Analog joystick and gamepad support
+ Specifies type or capabilities of an analog joystick
+ connected to one of 16 gameports
+ Format: <type1>,<type2>,..<type16>
+
+ apc= [HW,SPARC]
+ Power management functions (SPARCstation-4/5 + deriv.)
+ Format: noidle
+ Disable APC CPU standby support. SPARCstation-Fox does
+ not play well with APC CPU idle - disable it if you have
+ APC and your system crashes randomly.
+
+ apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
+ Change the output verbosity whilst booting
+ Format: { quiet (default) | verbose | debug }
+ Change the amount of debugging information output
+ when initialising the APIC and IO-APIC components.
+
+ apic_extnmi= [APIC,X86] External NMI delivery setting
+ Format: { bsp (default) | all | none }
+ bsp: External NMI is delivered only to CPU 0
+ all: External NMIs are broadcast to all CPUs as a
+ backup of CPU 0
+ none: External NMI is masked for all CPUs. This is
+ useful so that a dump capture kernel won't be
+ shot down by NMI
+
+ autoconf= [IPV6]
+ See Documentation/networking/ipv6.txt.
+
+ show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
+ Limit apic dumping. The parameter defines the maximal
+ number of local apics being dumped. Also it is possible
+ to set it to "all" by meaning -- no limit here.
+ Format: { 1 (default) | 2 | ... | all }.
+ The parameter valid if only apic=debug or
+ apic=verbose is specified.
+ Example: apic=debug show_lapic=all
+
+ apm= [APM] Advanced Power Management
+ See header of arch/x86/kernel/apm_32.c.
+
+ arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
+ Format: <io>,<irq>,<nodeID>
+
+ ataflop= [HW,M68k]
+
+ atarimouse= [HW,MOUSE] Atari Mouse
+
+ atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
+ EzKey and similar keyboards
+
+ atkbd.reset= [HW] Reset keyboard during initialization
+
+ atkbd.set= [HW] Select keyboard code set
+ Format: <int> (2 = AT (default), 3 = PS/2)
+
+ atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
+ keyboards
+
+ atkbd.softraw= [HW] Choose between synthetic and real raw mode
+ Format: <bool> (0 = real, 1 = synthetic (default))
+
+ atkbd.softrepeat= [HW]
+ Use software keyboard repeat
+
+ audit= [KNL] Enable the audit sub-system
+ Format: { "0" | "1" } (0 = disabled, 1 = enabled)
+ 0 - kernel audit is disabled and can not be enabled
+ until the next reboot
+ unset - kernel audit is initialized but disabled and
+ will be fully enabled by the userspace auditd.
+ 1 - kernel audit is initialized and partially enabled,
+ storing at most audit_backlog_limit messages in
+ RAM until it is fully enabled by the userspace
+ auditd.
+ Default: unset
+
+ audit_backlog_limit= [KNL] Set the audit queue size limit.
+ Format: <int> (must be >=0)
+ Default: 64
+
+ bau= [X86_UV] Enable the BAU on SGI UV. The default
+ behavior is to disable the BAU (i.e. bau=0).
+ Format: { "0" | "1" }
+ 0 - Disable the BAU.
+ 1 - Enable the BAU.
+ unset - Disable the BAU.
+
+ baycom_epp= [HW,AX25]
+ Format: <io>,<mode>
+
+ baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
+ Format: <io>,<mode>
+ See header of drivers/net/hamradio/baycom_par.c.
+
+ baycom_ser_fdx= [HW,AX25]
+ BayCom Serial Port AX.25 Modem (Full Duplex Mode)
+ Format: <io>,<irq>,<mode>[,<baud>]
+ See header of drivers/net/hamradio/baycom_ser_fdx.c.
+
+ baycom_ser_hdx= [HW,AX25]
+ BayCom Serial Port AX.25 Modem (Half Duplex Mode)
+ Format: <io>,<irq>,<mode>
+ See header of drivers/net/hamradio/baycom_ser_hdx.c.
+
+ blkdevparts= Manual partition parsing of block device(s) for
+ embedded devices based on command line input.
+ See Documentation/block/cmdline-partition.txt
+
+ boot_delay= Milliseconds to delay each printk during boot.
+ Values larger than 10 seconds (10000) are changed to
+ no delay (0).
+ Format: integer
+
+ bootmem_debug [KNL] Enable bootmem allocator debug messages.
+
+ bert_disable [ACPI]
+ Disable BERT OS support on buggy BIOSes.
+
+ bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
+ bttv.radio= Most important insmod options are available as
+ kernel args too.
+ bttv.pll= See Documentation/video4linux/bttv/Insmod-options
+ bttv.tuner=
+
+ bulk_remove=off [PPC] This parameter disables the use of the pSeries
+ firmware feature for flushing multiple hpte entries
+ at a time.
+
+ c101= [NET] Moxa C101 synchronous serial card
+
+ cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
+ Sometimes CPU hardware bugs make them report the cache
+ size incorrectly. The kernel will attempt work arounds
+ to fix known problems, but for some CPUs it is not
+ possible to determine what the correct size should be.
+ This option provides an override for these situations.
+
+ ca_keys= [KEYS] This parameter identifies a specific key(s) on
+ the system trusted keyring to be used for certificate
+ trust validation.
+ format: { id:<keyid> | builtin }
+
+ cca= [MIPS] Override the kernel pages' cache coherency
+ algorithm. Accepted values range from 0 to 7
+ inclusive. See arch/mips/include/asm/pgtable-bits.h
+ for platform specific values (SB1, Loongson3 and
+ others).
+
+ ccw_timeout_log [S390]
+ See Documentation/s390/CommonIO for details.
+
+ cgroup_disable= [KNL] Disable a particular controller
+ Format: {name of the controller(s) to disable}
+ The effects of cgroup_disable=foo are:
+ - foo isn't auto-mounted if you mount all cgroups in
+ a single hierarchy
+ - foo isn't visible as an individually mountable
+ subsystem
+ {Currently only "memory" controller deal with this and
+ cut the overhead, others just disable the usage. So
+ only cgroup_disable=memory is actually worthy}
+
+ cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1
+ Format: { controller[,controller...] | "all" }
+ Like cgroup_disable, but only applies to cgroup v1;
+ the blacklisted controllers remain available in cgroup2.
+
+ cgroup.memory= [KNL] Pass options to the cgroup memory controller.
+ Format: <string>
+ nosocket -- Disable socket memory accounting.
+ nokmem -- Disable kernel memory accounting.
+
+ checkreqprot [SELINUX] Set initial checkreqprot flag value.
+ Format: { "0" | "1" }
+ See security/selinux/Kconfig help text.
+ 0 -- check protection applied by kernel (includes
+ any implied execute protection).
+ 1 -- check protection requested by application.
+ Default value is set via a kernel config option.
+ Value can be changed at runtime via
+ /selinux/checkreqprot.
+
+ cio_ignore= [S390]
+ See Documentation/s390/CommonIO for details.
+ clk_ignore_unused
+ [CLK]
+ Prevents the clock framework from automatically gating
+ clocks that have not been explicitly enabled by a Linux
+ device driver but are enabled in hardware at reset or
+ by the bootloader/firmware. Note that this does not
+ force such clocks to be always-on nor does it reserve
+ those clocks in any way. This parameter is useful for
+ debug and development, but should not be needed on a
+ platform with proper driver support. For more
+ information, see Documentation/clk.txt.
+
+ clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
+ [Deprecated]
+ Forces specified clocksource (if available) to be used
+ when calculating gettimeofday(). If specified
+ clocksource is not available, it defaults to PIT.
+ Format: { pit | tsc | cyclone | pmtmr }
+
+ clocksource= Override the default clocksource
+ Format: <string>
+ Override the default clocksource and use the clocksource
+ with the name specified.
+ Some clocksource names to choose from, depending on
+ the platform:
+ [all] jiffies (this is the base, fallback clocksource)
+ [ACPI] acpi_pm
+ [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
+ pxa_timer,timer3,32k_counter,timer0_1
+ [AVR32] avr32
+ [X86-32] pit,hpet,tsc;
+ scx200_hrt on Geode; cyclone on IBM x440
+ [MIPS] MIPS
+ [PARISC] cr16
+ [S390] tod
+ [SH] SuperH
+ [SPARC64] tick
+ [X86-64] hpet,tsc
+
+ clocksource.arm_arch_timer.evtstrm=
+ [ARM,ARM64]
+ Format: <bool>
+ Enable/disable the eventstream feature of the ARM
+ architected timer so that code using WFE-based polling
+ loops can be debugged more effectively on production
+ systems.
+
+ clocksource.arm_arch_timer.fsl-a008585=
+ [ARM64]
+ Format: <bool>
+ Enable/disable the workaround of Freescale/NXP
+ erratum A-008585. This can be useful for KVM
+ guests, if the guest device tree doesn't show the
+ erratum. If unspecified, the workaround is
+ enabled based on the device tree.
+
+ clearcpuid=BITNUM [X86]
+ Disable CPUID feature X for the kernel. See
+ arch/x86/include/asm/cpufeatures.h for the valid bit
+ numbers. Note the Linux specific bits are not necessarily
+ stable over kernel options, but the vendor specific
+ ones should be.
+ Also note that user programs calling CPUID directly
+ or using the feature without checking anything
+ will still see it. This just prevents it from
+ being used by the kernel or shown in /proc/cpuinfo.
+ Also note the kernel might malfunction if you disable
+ some critical bits.
+
+ cma=nn[MG]@[start[MG][-end[MG]]]
+ [ARM,X86,KNL]
+ Sets the size of kernel global memory area for
+ contiguous memory allocations and optionally the
+ placement constraint by the physical address range of
+ memory allocations. A value of 0 disables CMA
+ altogether. For more information, see
+ include/linux/dma-contiguous.h
+
+ cmo_free_hint= [PPC] Format: { yes | no }
+ Specify whether pages are marked as being inactive
+ when they are freed. This is used in CMO environments
+ to determine OS memory pressure for page stealing by
+ a hypervisor.
+ Default: yes
+
+ coherent_pool=nn[KMG] [ARM,KNL]
+ Sets the size of memory pool for coherent, atomic dma
+ allocations, by default set to 256K.
+
+ code_bytes [X86] How many bytes of object code to print
+ in an oops report.
+ Range: 0 - 8192
+ Default: 64
+
+ com20020= [HW,NET] ARCnet - COM20020 chipset
+ Format:
+ <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
+
+ com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
+ Format: <io>[,<irq>]
+
+ com90xx= [HW,NET]
+ ARCnet - COM90xx chipset (memory-mapped buffers)
+ Format: <io>[,<irq>[,<memstart>]]
+
+ condev= [HW,S390] console device
+ conmode=
+
+ console= [KNL] Output console device and options.
+
+ tty<n> Use the virtual console device <n>.
+
+ ttyS<n>[,options]
+ ttyUSB0[,options]
+ Use the specified serial port. The options are of
+ the form "bbbbpnf", where "bbbb" is the baud rate,
+ "p" is parity ("n", "o", or "e"), "n" is number of
+ bits, and "f" is flow control ("r" for RTS or
+ omit it). Default is "9600n8".
+
+ See Documentation/serial-console.txt for more
+ information. See
+ Documentation/networking/netconsole.txt for an
+ alternative.
+
+ uart[8250],io,<addr>[,options]
+ uart[8250],mmio,<addr>[,options]
+ uart[8250],mmio16,<addr>[,options]
+ uart[8250],mmio32,<addr>[,options]
+ uart[8250],0x<addr>[,options]
+ Start an early, polled-mode console on the 8250/16550
+ UART at the specified I/O port or MMIO address,
+ switching to the matching ttyS device later.
+ MMIO inter-register address stride is either 8-bit
+ (mmio), 16-bit (mmio16), or 32-bit (mmio32).
+ If none of [io|mmio|mmio16|mmio32], <addr> is assumed
+ to be equivalent to 'mmio'. 'options' are specified in
+ the same format described for ttyS above; if unspecified,
+ the h/w is not re-initialized.
+
+ hvc<n> Use the hypervisor console device <n>. This is for
+ both Xen and PowerPC hypervisors.
+
+ If the device connected to the port is not a TTY but a braille
+ device, prepend "brl," before the device type, for instance
+ console=brl,ttyS0
+ For now, only VisioBraille is supported.
+
+ consoleblank= [KNL] The console blank (screen saver) timeout in
+ seconds. Defaults to 10*60 = 10mins. A value of 0
+ disables the blank timer.
+
+ coredump_filter=
+ [KNL] Change the default value for
+ /proc/<pid>/coredump_filter.
+ See also Documentation/filesystems/proc.txt.
+
+ cpuidle.off=1 [CPU_IDLE]
+ disable the cpuidle sub-system
+
+ cpu_init_udelay=N
+ [X86] Delay for N microsec between assert and de-assert
+ of APIC INIT to start processors. This delay occurs
+ on every CPU online, such as boot, and resume from suspend.
+ Default: 10000
+
+ cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
+ Format:
+ <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
+
+ crashkernel=size[KMG][@offset[KMG]]
+ [KNL] Using kexec, Linux can switch to a 'crash kernel'
+ upon panic. This parameter reserves the physical
+ memory region [offset, offset + size] for that kernel
+ image. If '@offset' is omitted, then a suitable offset
+ is selected automatically. Check
+ Documentation/kdump/kdump.txt for further details.
+
+ crashkernel=range1:size1[,range2:size2,...][@offset]
+ [KNL] Same as above, but depends on the memory
+ in the running system. The syntax of range is
+ start-[end] where start and end are both
+ a memory unit (amount[KMG]). See also
+ Documentation/kdump/kdump.txt for an example.
+
+ crashkernel=size[KMG],high
+ [KNL, x86_64] range could be above 4G. Allow kernel
+ to allocate physical memory region from top, so could
+ be above 4G if system have more than 4G ram installed.
+ Otherwise memory region will be allocated below 4G, if
+ available.
+ It will be ignored if crashkernel=X is specified.
+ crashkernel=size[KMG],low
+ [KNL, x86_64] range under 4G. When crashkernel=X,high
+ is passed, kernel could allocate physical memory region
+ above 4G, that cause second kernel crash on system
+ that require some amount of low memory, e.g. swiotlb
+ requires at least 64M+32K low memory, also enough extra
+ low memory is needed to make sure DMA buffers for 32-bit
+ devices won't run out. Kernel would try to allocate at
+ at least 256M below 4G automatically.
+ This one let user to specify own low range under 4G
+ for second kernel instead.
+ 0: to disable low allocation.
+ It will be ignored when crashkernel=X,high is not used
+ or memory reserved is below 4G.
+
+ cryptomgr.notests
+ [KNL] Disable crypto self-tests
+
+ cs89x0_dma= [HW,NET]
+ Format: <dma>
+
+ cs89x0_media= [HW,NET]
+ Format: { rj45 | aui | bnc }
+
+ dasd= [HW,NET]
+ See header of drivers/s390/block/dasd_devmap.c.
+
+ db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
+ (one device per port)
+ Format: <port#>,<type>
+ See also Documentation/input/joystick-parport.txt
+
+ ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
+ time. See Documentation/dynamic-debug-howto.txt for
+ details. Deprecated, see dyndbg.
+
+ debug [KNL] Enable kernel debugging (events log level).
+
+ debug_locks_verbose=
+ [KNL] verbose self-tests
+ Format=<0|1>
+ Print debugging info while doing the locking API
+ self-tests.
+ We default to 0 (no extra messages), setting it to
+ 1 will print _a lot_ more information - normally
+ only useful to kernel developers.
+
+ debug_objects [KNL] Enable object debugging
+
+ no_debug_objects
+ [KNL] Disable object debugging
+
+ debug_guardpage_minorder=
+ [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
+ parameter allows control of the order of pages that will
+ be intentionally kept free (and hence protected) by the
+ buddy allocator. Bigger value increase the probability
+ of catching random memory corruption, but reduce the
+ amount of memory for normal system use. The maximum
+ possible value is MAX_ORDER/2. Setting this parameter
+ to 1 or 2 should be enough to identify most random
+ memory corruption problems caused by bugs in kernel or
+ driver code when a CPU writes to (or reads from) a
+ random memory location. Note that there exists a class
+ of memory corruptions problems caused by buggy H/W or
+ F/W or by drivers badly programing DMA (basically when
+ memory is written at bus level and the CPU MMU is
+ bypassed) which are not detectable by
+ CONFIG_DEBUG_PAGEALLOC, hence this option will not help
+ tracking down these problems.
+
+ debug_pagealloc=
+ [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
+ parameter enables the feature at boot time. In
+ default, it is disabled. We can avoid allocating huge
+ chunk of memory for debug pagealloc if we don't enable
+ it at boot time and the system will work mostly same
+ with the kernel built without CONFIG_DEBUG_PAGEALLOC.
+ on: enable the feature
+
+ debugpat [X86] Enable PAT debugging
+
+ decnet.addr= [HW,NET]
+ Format: <area>[,<node>]
+ See also Documentation/networking/decnet.txt.
+
+ default_hugepagesz=
+ [same as hugepagesz=] The size of the default
+ HugeTLB page size. This is the size represented by
+ the legacy /proc/ hugepages APIs, used for SHM, and
+ default size when mounting hugetlbfs filesystems.
+ Defaults to the default architecture's huge page size
+ if not specified.
+
+ dhash_entries= [KNL]
+ Set number of hash buckets for dentry cache.
+
+ disable_1tb_segments [PPC]
+ Disables the use of 1TB hash page table segments. This
+ causes the kernel to fall back to 256MB segments which
+ can be useful when debugging issues that require an SLB
+ miss to occur.
+
+ disable= [IPV6]
+ See Documentation/networking/ipv6.txt.
+
+ disable_radix [PPC]
+ Disable RADIX MMU mode on POWER9
+
+ disable_cpu_apicid= [X86,APIC,SMP]
+ Format: <int>
+ The number of initial APIC ID for the
+ corresponding CPU to be disabled at boot,
+ mostly used for the kdump 2nd kernel to
+ disable BSP to wake up multiple CPUs without
+ causing system reset or hang due to sending
+ INIT from AP to BSP.
+
+ disable_ddw [PPC/PSERIES]
+ Disable Dynamic DMA Window support. Use this if
+ to workaround buggy firmware.
+
+ disable_ipv6= [IPV6]
+ See Documentation/networking/ipv6.txt.
+
+ disable_mtrr_cleanup [X86]
+ The kernel tries to adjust MTRR layout from continuous
+ to discrete, to make X server driver able to add WB
+ entry later. This parameter disables that.
+
+ disable_mtrr_trim [X86, Intel and AMD only]
+ By default the kernel will trim any uncacheable
+ memory out of your available memory pool based on
+ MTRR settings. This parameter disables that behavior,
+ possibly causing your machine to run very slowly.
+
+ disable_timer_pin_1 [X86]
+ Disable PIN 1 of APIC timer
+ Can be useful to work around chipset bugs.
+
+ dis_ucode_ldr [X86] Disable the microcode loader.
+
+ dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
+ this option disables the debugging code at boot.
+
+ dma_debug_entries=<number>
+ This option allows to tune the number of preallocated
+ entries for DMA-API debugging code. One entry is
+ required per DMA-API allocation. Use this if the
+ DMA-API debugging code disables itself because the
+ architectural default is too low.
+
+ dma_debug_driver=<driver_name>
+ With this option the DMA-API debugging driver
+ filter feature can be enabled at boot time. Just
+ pass the driver to filter for as the parameter.
+ The filter can be disabled or changed to another
+ driver later using sysfs.
+
+ drm_kms_helper.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
+ Broken monitors, graphic adapters, KVMs and EDIDless
+ panels may send no or incorrect EDID data sets.
+ This parameter allows to specify an EDID data sets
+ in the /lib/firmware directory that are used instead.
+ Generic built-in EDID data sets are used, if one of
+ edid/1024x768.bin, edid/1280x1024.bin,
+ edid/1680x1050.bin, or edid/1920x1080.bin is given
+ and no file with the same name exists. Details and
+ instructions how to build your own EDID data are
+ available in Documentation/EDID/HOWTO.txt. An EDID
+ data set will only be used for a particular connector,
+ if its name and a colon are prepended to the EDID
+ name. Each connector may use a unique EDID data
+ set by separating the files with a comma. An EDID
+ data set with no connector name will be used for
+ any connectors not explicitly specified.
+
+ dscc4.setup= [NET]
+
+ dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
+ module.dyndbg[="val"]
+ Enable debug messages at boot time. See
+ Documentation/dynamic-debug-howto.txt for details.
+
+ nompx [X86] Disables Intel Memory Protection Extensions.
+ See Documentation/x86/intel_mpx.txt for more
+ information about the feature.
+
+ nopku [X86] Disable Memory Protection Keys CPU feature found
+ in some Intel CPUs.
+
+ eagerfpu= [X86]
+ on enable eager fpu restore
+ off disable eager fpu restore
+ auto selects the default scheme, which automatically
+ enables eagerfpu restore for xsaveopt.
+
+ module.async_probe [KNL]
+ Enable asynchronous probe on this module.
+
+ early_ioremap_debug [KNL]
+ Enable debug messages in early_ioremap support. This
+ is useful for tracking down temporary early mappings
+ which are not unmapped.
+
+ earlycon= [KNL] Output early console device and options.
+
+ When used with no options, the early console is
+ determined by the stdout-path property in device
+ tree's chosen node.
+
+ cdns,<addr>[,options]
+ Start an early, polled-mode console on a Cadence
+ (xuartps) serial port at the specified address. Only
+ supported option is baud rate. If baud rate is not
+ specified, the serial port must already be setup and
+ configured.
+
+ uart[8250],io,<addr>[,options]
+ uart[8250],mmio,<addr>[,options]
+ uart[8250],mmio32,<addr>[,options]
+ uart[8250],mmio32be,<addr>[,options]
+ uart[8250],0x<addr>[,options]
+ Start an early, polled-mode console on the 8250/16550
+ UART at the specified I/O port or MMIO address.
+ MMIO inter-register address stride is either 8-bit
+ (mmio) or 32-bit (mmio32 or mmio32be).
+ If none of [io|mmio|mmio32|mmio32be], <addr> is assumed
+ to be equivalent to 'mmio'. 'options' are specified
+ in the same format described for "console=ttyS<n>"; if
+ unspecified, the h/w is not initialized.
+
+ pl011,<addr>
+ pl011,mmio32,<addr>
+ Start an early, polled-mode console on a pl011 serial
+ port at the specified address. The pl011 serial port
+ must already be setup and configured. Options are not
+ yet supported. If 'mmio32' is specified, then only
+ the driver will use only 32-bit accessors to read/write
+ the device registers.
+
+ meson,<addr>
+ Start an early, polled-mode console on a meson serial
+ port at the specified address. The serial port must
+ already be setup and configured. Options are not yet
+ supported.
+
+ msm_serial,<addr>
+ Start an early, polled-mode console on an msm serial
+ port at the specified address. The serial port
+ must already be setup and configured. Options are not
+ yet supported.
+
+ msm_serial_dm,<addr>
+ Start an early, polled-mode console on an msm serial
+ dm port at the specified address. The serial port
+ must already be setup and configured. Options are not
+ yet supported.
+
+ smh Use ARM semihosting calls for early console.
+
+ s3c2410,<addr>
+ s3c2412,<addr>
+ s3c2440,<addr>
+ s3c6400,<addr>
+ s5pv210,<addr>
+ exynos4210,<addr>
+ Use early console provided by serial driver available
+ on Samsung SoCs, requires selecting proper type and
+ a correct base address of the selected UART port. The
+ serial port must already be setup and configured.
+ Options are not yet supported.
+
+ lpuart,<addr>
+ lpuart32,<addr>
+ Use early console provided by Freescale LP UART driver
+ found on Freescale Vybrid and QorIQ LS1021A processors.
+ A valid base address must be provided, and the serial
+ port must already be setup and configured.
+
+ armada3700_uart,<addr>
+ Start an early, polled-mode console on the
+ Armada 3700 serial port at the specified
+ address. The serial port must already be setup
+ and configured. Options are not yet supported.
+
+ earlyprintk= [X86,SH,BLACKFIN,ARM,M68k]
+ earlyprintk=vga
+ earlyprintk=efi
+ earlyprintk=xen
+ earlyprintk=serial[,ttySn[,baudrate]]
+ earlyprintk=serial[,0x...[,baudrate]]
+ earlyprintk=ttySn[,baudrate]
+ earlyprintk=dbgp[debugController#]
+ earlyprintk=pciserial,bus:device.function[,baudrate]
+
+ earlyprintk is useful when the kernel crashes before
+ the normal console is initialized. It is not enabled by
+ default because it has some cosmetic problems.
+
+ Append ",keep" to not disable it when the real console
+ takes over.
+
+ Only one of vga, efi, serial, or usb debug port can
+ be used at a time.
+
+ Currently only ttyS0 and ttyS1 may be specified by
+ name. Other I/O ports may be explicitly specified
+ on some architectures (x86 and arm at least) by
+ replacing ttySn with an I/O port address, like this:
+ earlyprintk=serial,0x1008,115200
+ You can find the port for a given device in
+ /proc/tty/driver/serial:
+ 2: uart:ST16650V2 port:00001008 irq:18 ...
+
+ Interaction with the standard serial driver is not
+ very good.
+
+ The VGA and EFI output is eventually overwritten by
+ the real console.
+
+ The xen output can only be used by Xen PV guests.
+
+ edac_report= [HW,EDAC] Control how to report EDAC event
+ Format: {"on" | "off" | "force"}
+ on: enable EDAC to report H/W event. May be overridden
+ by other higher priority error reporting module.
+ off: disable H/W event reporting through EDAC.
+ force: enforce the use of EDAC to report H/W event.
+ default: on.
+
+ ekgdboc= [X86,KGDB] Allow early kernel console debugging
+ ekgdboc=kbd
+
+ This is designed to be used in conjunction with
+ the boot argument: earlyprintk=vga
+
+ edd= [EDD]
+ Format: {"off" | "on" | "skip[mbr]"}
+
+ efi= [EFI]
+ Format: { "old_map", "nochunk", "noruntime", "debug" }
+ old_map [X86-64]: switch to the old ioremap-based EFI
+ runtime services mapping. 32-bit still uses this one by
+ default.
+ nochunk: disable reading files in "chunks" in the EFI
+ boot stub, as chunking can cause problems with some
+ firmware implementations.
+ noruntime : disable EFI runtime services support
+ debug: enable misc debug output
+
+ efi_no_storage_paranoia [EFI; X86]
+ Using this parameter you can use more than 50% of
+ your efi variable storage. Use this parameter only if
+ you are really sure that your UEFI does sane gc and
+ fulfills the spec otherwise your board may brick.
+
+ efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI; X86]
+ Add arbitrary attribute to specific memory range by
+ updating original EFI memory map.
+ Region of memory which aa attribute is added to is
+ from ss to ss+nn.
+ If efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000
+ is specified, EFI_MEMORY_MORE_RELIABLE(0x10000)
+ attribute is added to range 0x100000000-0x180000000 and
+ 0x10a0000000-0x1120000000.
+
+ Using this parameter you can do debugging of EFI memmap
+ related feature. For example, you can do debugging of
+ Address Range Mirroring feature even if your box
+ doesn't support it.
+
+ efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT
+ that is to be dynamically loaded by Linux. If there are
+ multiple variables with the same name but with different
+ vendor GUIDs, all of them will be loaded. See
+ Documentation/acpi/ssdt-overlays.txt for details.
+
+
+ eisa_irq_edge= [PARISC,HW]
+ See header of drivers/parisc/eisa.c.
+
+ elanfreq= [X86-32]
+ See comment before function elanfreq_setup() in
+ arch/x86/kernel/cpu/cpufreq/elanfreq.c.
+
+ elevator= [IOSCHED]
+ Format: {"cfq" | "deadline" | "noop"}
+ See Documentation/block/cfq-iosched.txt and
+ Documentation/block/deadline-iosched.txt for details.
+
+ elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
+ Specifies physical address of start of kernel core
+ image elf header and optionally the size. Generally
+ kexec loader will pass this option to capture kernel.
+ See Documentation/kdump/kdump.txt for details.
+
+ enable_mtrr_cleanup [X86]
+ The kernel tries to adjust MTRR layout from continuous
+ to discrete, to make X server driver able to add WB
+ entry later. This parameter enables that.
+
+ enable_timer_pin_1 [X86]
+ Enable PIN 1 of APIC timer
+ Can be useful to work around chipset bugs
+ (in particular on some ATI chipsets).
+ The kernel tries to set a reasonable default.
+
+ enforcing [SELINUX] Set initial enforcing status.
+ Format: {"0" | "1"}
+ See security/selinux/Kconfig help text.
+ 0 -- permissive (log only, no denials).
+ 1 -- enforcing (deny and log).
+ Default value is 0.
+ Value can be changed at runtime via /selinux/enforce.
+
+ erst_disable [ACPI]
+ Disable Error Record Serialization Table (ERST)
+ support.
+
+ ether= [HW,NET] Ethernet cards parameters
+ This option is obsoleted by the "netdev=" option, which
+ has equivalent usage. See its documentation for details.
+
+ evm= [EVM]
+ Format: { "fix" }
+ Permit 'security.evm' to be updated regardless of
+ current integrity status.
+
+ failslab=
+ fail_page_alloc=
+ fail_make_request=[KNL]
+ General fault injection mechanism.
+ Format: <interval>,<probability>,<space>,<times>
+ See also Documentation/fault-injection/.
+
+ floppy= [HW]
+ See Documentation/blockdev/floppy.txt.
+
+ force_pal_cache_flush
+ [IA-64] Avoid check_sal_cache_flush which may hang on
+ buggy SAL_CACHE_FLUSH implementations. Using this
+ parameter will force ia64_sal_cache_flush to call
+ ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
+
+ forcepae [X86-32]
+ Forcefully enable Physical Address Extension (PAE).
+ Many Pentium M systems disable PAE but may have a
+ functionally usable PAE implementation.
+ Warning: use of this parameter will taint the kernel
+ and may cause unknown problems.
+
+ ftrace=[tracer]
+ [FTRACE] will set and start the specified tracer
+ as early as possible in order to facilitate early
+ boot debugging.
+
+ ftrace_dump_on_oops[=orig_cpu]
+ [FTRACE] will dump the trace buffers on oops.
+ If no parameter is passed, ftrace will dump
+ buffers of all CPUs, but if you pass orig_cpu, it will
+ dump only the buffer of the CPU that triggered the
+ oops.
+
+ ftrace_filter=[function-list]
+ [FTRACE] Limit the functions traced by the function
+ tracer at boot up. function-list is a comma separated
+ list of functions. This list can be changed at run
+ time by the set_ftrace_filter file in the debugfs
+ tracing directory.
+
+ ftrace_notrace=[function-list]
+ [FTRACE] Do not trace the functions specified in
+ function-list. This list can be changed at run time
+ by the set_ftrace_notrace file in the debugfs
+ tracing directory.
+
+ ftrace_graph_filter=[function-list]
+ [FTRACE] Limit the top level callers functions traced
+ by the function graph tracer at boot up.
+ function-list is a comma separated list of functions
+ that can be changed at run time by the
+ set_graph_function file in the debugfs tracing directory.
+
+ ftrace_graph_notrace=[function-list]
+ [FTRACE] Do not trace from the functions specified in
+ function-list. This list is a comma separated list of
+ functions that can be changed at run time by the
+ set_graph_notrace file in the debugfs tracing directory.
+
+ gamecon.map[2|3]=
+ [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
+ support via parallel port (up to 5 devices per port)
+ Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
+ See also Documentation/input/joystick-parport.txt
+
+ gamma= [HW,DRM]
+
+ gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
+ Format: off | on
+ default: on
+
+ gcov_persist= [GCOV] When non-zero (default), profiling data for
+ kernel modules is saved and remains accessible via
+ debugfs, even when the module is unloaded/reloaded.
+ When zero, profiling data is discarded and associated
+ debugfs files are removed at module unload time.
+
+ gpt [EFI] Forces disk with valid GPT signature but
+ invalid Protective MBR to be treated as GPT. If the
+ primary GPT is corrupted, it enables the backup/alternate
+ GPT to be used instead.
+
+ grcan.enable0= [HW] Configuration of physical interface 0. Determines
+ the "Enable 0" bit of the configuration register.
+ Format: 0 | 1
+ Default: 0
+ grcan.enable1= [HW] Configuration of physical interface 1. Determines
+ the "Enable 0" bit of the configuration register.
+ Format: 0 | 1
+ Default: 0
+ grcan.select= [HW] Select which physical interface to use.
+ Format: 0 | 1
+ Default: 0
+ grcan.txsize= [HW] Sets the size of the tx buffer.
+ Format: <unsigned int> such that (txsize & ~0x1fffc0) == 0.
+ Default: 1024
+ grcan.rxsize= [HW] Sets the size of the rx buffer.
+ Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
+ Default: 1024
+
+ gpio-mockup.gpio_mockup_ranges
+ [HW] Sets the ranges of gpiochip of for this device.
+ Format: <start1>,<end1>,<start2>,<end2>...
+
+ hardlockup_all_cpu_backtrace=
+ [KNL] Should the hard-lockup detector generate
+ backtraces on all cpus.
+ Format: <integer>
+
+ hashdist= [KNL,NUMA] Large hashes allocated during boot
+ are distributed across NUMA nodes. Defaults on
+ for 64-bit NUMA, off otherwise.
+ Format: 0 | 1 (for off | on)
+
+ hcl= [IA-64] SGI's Hardware Graph compatibility layer
+
+ hd= [EIDE] (E)IDE hard drive subsystem geometry
+ Format: <cyl>,<head>,<sect>
+
+ hest_disable [ACPI]
+ Disable Hardware Error Source Table (HEST) support;
+ corresponding firmware-first mode error processing
+ logic will be disabled.
+
+ highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
+ size of <nn>. This works even on boxes that have no
+ highmem otherwise. This also works to reduce highmem
+ size on bigger boxes.
+
+ highres= [KNL] Enable/disable high resolution timer mode.
+ Valid parameters: "on", "off"
+ Default: "on"
+
+ hisax= [HW,ISDN]
+ See Documentation/isdn/README.HiSax.
+
+ hlt [BUGS=ARM,SH]
+
+ hpet= [X86-32,HPET] option to control HPET usage
+ Format: { enable (default) | disable | force |
+ verbose }
+ disable: disable HPET and use PIT instead
+ force: allow force enabled of undocumented chips (ICH4,
+ VIA, nVidia)
+ verbose: show contents of HPET registers during setup
+
+ hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET
+ registers. Default set by CONFIG_HPET_MMAP_DEFAULT.
+
+ hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
+ hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
+ On x86-64 and powerpc, this option can be specified
+ multiple times interleaved with hugepages= to reserve
+ huge pages of different sizes. Valid pages sizes on
+ x86-64 are 2M (when the CPU supports "pse") and 1G
+ (when the CPU supports the "pdpe1gb" cpuinfo flag).
+
+ hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
+ terminal devices. Valid values: 0..8
+ hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
+ If specified, z/VM IUCV HVC accepts connections
+ from listed z/VM user IDs only.
+
+ hwthread_map= [METAG] Comma-separated list of Linux cpu id to
+ hardware thread id mappings.
+ Format: <cpu>:<hwthread>
+
+ keep_bootcon [KNL]
+ Do not unregister boot console at start. This is only
+ useful for debugging when something happens in the window
+ between unregistering the boot console and initializing
+ the real console.
+
+ i2c_bus= [HW] Override the default board specific I2C bus speed
+ or register an additional I2C bus that is not
+ registered from board initialization code.
+ Format:
+ <bus_id>,<clkrate>
+
+ i8042.debug [HW] Toggle i8042 debug mode
+ i8042.unmask_kbd_data
+ [HW] Enable printing of interrupt data from the KBD port
+ (disabled by default, and as a pre-condition
+ requires that i8042.debug=1 be enabled)
+ i8042.direct [HW] Put keyboard port into non-translated mode
+ i8042.dumbkbd [HW] Pretend that controller can only read data from
+ keyboard and cannot control its state
+ (Don't attempt to blink the leds)
+ i8042.noaux [HW] Don't check for auxiliary (== mouse) port
+ i8042.nokbd [HW] Don't check/create keyboard port
+ i8042.noloop [HW] Disable the AUX Loopback command while probing
+ for the AUX port
+ i8042.nomux [HW] Don't check presence of an active multiplexing
+ controller
+ i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
+ controllers
+ i8042.notimeout [HW] Ignore timeout condition signalled by controller
+ i8042.reset [HW] Reset the controller during init, cleanup and
+ suspend-to-ram transitions, only during s2r
+ transitions, or never reset
+ Format: { 1 | Y | y | 0 | N | n }
+ 1, Y, y: always reset controller
+ 0, N, n: don't ever reset controller
+ Default: only on s2r transitions on x86; most other
+ architectures force reset to be always executed
+ i8042.unlock [HW] Unlock (ignore) the keylock
+ i8042.kbdreset [HW] Reset device connected to KBD port
+
+ i810= [HW,DRM]
+
+ i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
+ indicates that the driver is running on unsupported
+ hardware.
+ i8k.force [HW] Activate i8k driver even if SMM BIOS signature
+ does not match list of supported models.
+ i8k.power_status
+ [HW] Report power status in /proc/i8k
+ (disabled by default)
+ i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
+ capability is set.
+
+ i915.invert_brightness=
+ [DRM] Invert the sense of the variable that is used to
+ set the brightness of the panel backlight. Normally a
+ brightness value of 0 indicates backlight switched off,
+ and the maximum of the brightness value sets the backlight
+ to maximum brightness. If this parameter is set to 0
+ (default) and the machine requires it, or this parameter
+ is set to 1, a brightness value of 0 sets the backlight
+ to maximum brightness, and the maximum of the brightness
+ value switches the backlight off.
+ -1 -- never invert brightness
+ 0 -- machine default
+ 1 -- force brightness inversion
+
+ icn= [HW,ISDN]
+ Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
+
+ ide-core.nodma= [HW] (E)IDE subsystem
+ Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
+ .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
+ .cdrom .chs .ignore_cable are additional options
+ See Documentation/ide/ide.txt.
+
+ ide-generic.probe-mask= [HW] (E)IDE subsystem
+ Format: <int>
+ Probe mask for legacy ISA IDE ports. Depending on
+ platform up to 6 ports are supported, enabled by
+ setting corresponding bits in the mask to 1. The
+ default value is 0x0, which has a special meaning.
+ On systems that have PCI, it triggers scanning the
+ PCI bus for the first and the second port, which
+ are then probed. On systems without PCI the value
+ of 0x0 enables probing the two first ports as if it
+ was 0x3.
+
+ ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
+ Claim all unknown PCI IDE storage controllers.
+
+ idle= [X86]
+ Format: idle=poll, idle=halt, idle=nomwait
+ Poll forces a polling idle loop that can slightly
+ improve the performance of waking up a idle CPU, but
+ will use a lot of power and make the system run hot.
+ Not recommended.
+ idle=halt: Halt is forced to be used for CPU idle.
+ In such case C2/C3 won't be used again.
+ idle=nomwait: Disable mwait for CPU C-states
+
+ ieee754= [MIPS] Select IEEE Std 754 conformance mode
+ Format: { strict | legacy | 2008 | relaxed }
+ Default: strict
+
+ Choose which programs will be accepted for execution
+ based on the IEEE 754 NaN encoding(s) supported by
+ the FPU and the NaN encoding requested with the value
+ of an ELF file header flag individually set by each
+ binary. Hardware implementations are permitted to
+ support either or both of the legacy and the 2008 NaN
+ encoding mode.
+
+ Available settings are as follows:
+ strict accept binaries that request a NaN encoding
+ supported by the FPU
+ legacy only accept legacy-NaN binaries, if supported
+ by the FPU
+ 2008 only accept 2008-NaN binaries, if supported
+ by the FPU
+ relaxed accept any binaries regardless of whether
+ supported by the FPU
+
+ The FPU emulator is always able to support both NaN
+ encodings, so if no FPU hardware is present or it has
+ been disabled with 'nofpu', then the settings of
+ 'legacy' and '2008' strap the emulator accordingly,
+ 'relaxed' straps the emulator for both legacy-NaN and
+ 2008-NaN, whereas 'strict' enables legacy-NaN only on
+ legacy processors and both NaN encodings on MIPS32 or
+ MIPS64 CPUs.
+
+ The setting for ABS.fmt/NEG.fmt instruction execution
+ mode generally follows that for the NaN encoding,
+ except where unsupported by hardware.
+
+ ignore_loglevel [KNL]
+ Ignore loglevel setting - this will print /all/
+ kernel messages to the console. Useful for debugging.
+ We also add it as printk module parameter, so users
+ could change it dynamically, usually by
+ /sys/module/printk/parameters/ignore_loglevel.
+
+ ignore_rlimit_data
+ Ignore RLIMIT_DATA setting for data mappings,
+ print warning at first misuse. Can be changed via
+ /sys/module/kernel/parameters/ignore_rlimit_data.
+
+ ihash_entries= [KNL]
+ Set number of hash buckets for inode cache.
+
+ ima_appraise= [IMA] appraise integrity measurements
+ Format: { "off" | "enforce" | "fix" | "log" }
+ default: "enforce"
+
+ ima_appraise_tcb [IMA]
+ The builtin appraise policy appraises all files
+ owned by uid=0.
+
+ ima_hash= [IMA]
+ Format: { md5 | sha1 | rmd160 | sha256 | sha384
+ | sha512 | ... }
+ default: "sha1"
+
+ The list of supported hash algorithms is defined
+ in crypto/hash_info.h.
+
+ ima_policy= [IMA]
+ The builtin measurement policy to load during IMA
+ setup. Specyfing "tcb" as the value, measures all
+ programs exec'd, files mmap'd for exec, and all files
+ opened with the read mode bit set by either the
+ effective uid (euid=0) or uid=0.
+ Format: "tcb"
+
+ ima_tcb [IMA] Deprecated. Use ima_policy= instead.
+ Load a policy which meets the needs of the Trusted
+ Computing Base. This means IMA will measure all
+ programs exec'd, files mmap'd for exec, and all files
+ opened for read by uid=0.
+
+ ima_template= [IMA]
+ Select one of defined IMA measurements template formats.
+ Formats: { "ima" | "ima-ng" | "ima-sig" }
+ Default: "ima-ng"
+
+ ima_template_fmt=
+ [IMA] Define a custom template format.
+ Format: { "field1|...|fieldN" }
+
+ ima.ahash_minsize= [IMA] Minimum file size for asynchronous hash usage
+ Format: <min_file_size>
+ Set the minimal file size for using asynchronous hash.
+ If left unspecified, ahash usage is disabled.
+
+ ahash performance varies for different data sizes on
+ different crypto accelerators. This option can be used
+ to achieve the best performance for a particular HW.
+
+ ima.ahash_bufsize= [IMA] Asynchronous hash buffer size
+ Format: <bufsize>
+ Set hashing buffer size. Default: 4k.
+
+ ahash performance varies for different chunk sizes on
+ different crypto accelerators. This option can be used
+ to achieve best performance for particular HW.
+
+ init= [KNL]
+ Format: <full_path>
+ Run specified binary instead of /sbin/init as init
+ process.
+
+ initcall_debug [KNL] Trace initcalls as they are executed. Useful
+ for working out where the kernel is dying during
+ startup.
+
+ initcall_blacklist= [KNL] Do not execute a comma-separated list of
+ initcall functions. Useful for debugging built-in
+ modules and initcalls.
+
+ initrd= [BOOT] Specify the location of the initial ramdisk
+
+ init_pkru= [x86] Specify the default memory protection keys rights
+ register contents for all processes. 0x55555554 by
+ default (disallow access to all but pkey 0). Can
+ override in debugfs after boot.
+
+ inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
+ Format: <irq>
+
+ int_pln_enable [x86] Enable power limit notification interrupt
+
+ integrity_audit=[IMA]
+ Format: { "0" | "1" }
+ 0 -- basic integrity auditing messages. (Default)
+ 1 -- additional integrity auditing messages.
+
+ intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
+ on
+ Enable intel iommu driver.
+ off
+ Disable intel iommu driver.
+ igfx_off [Default Off]
+ By default, gfx is mapped as normal device. If a gfx
+ device has a dedicated DMAR unit, the DMAR unit is
+ bypassed by not enabling DMAR with this option. In
+ this case, gfx device will use physical address for
+ DMA.
+ forcedac [x86_64]
+ With this option iommu will not optimize to look
+ for io virtual address below 32-bit forcing dual
+ address cycle on pci bus for cards supporting greater
+ than 32-bit addressing. The default is to look
+ for translation below 32-bit and if not available
+ then look in the higher range.
+ strict [Default Off]
+ With this option on every unmap_single operation will
+ result in a hardware IOTLB flush operation as opposed
+ to batching them for performance.
+ sp_off [Default Off]
+ By default, super page will be supported if Intel IOMMU
+ has the capability. With this option, super page will
+ not be supported.
+ ecs_off [Default Off]
+ By default, extended context tables will be supported if
+ the hardware advertises that it has support both for the
+ extended tables themselves, and also PASID support. With
+ this option set, extended tables will not be used even
+ on hardware which claims to support them.
+
+ intel_idle.max_cstate= [KNL,HW,ACPI,X86]
+ 0 disables intel_idle and fall back on acpi_idle.
+ 1 to 9 specify maximum depth of C-state.
+
+ intel_pstate= [X86]
+ disable
+ Do not enable intel_pstate as the default
+ scaling driver for the supported processors
+ force
+ Enable intel_pstate on systems that prohibit it by default
+ in favor of acpi-cpufreq. Forcing the intel_pstate driver
+ instead of acpi-cpufreq may disable platform features, such
+ as thermal controls and power capping, that rely on ACPI
+ P-States information being indicated to OSPM and therefore
+ should be used with caution. This option does not work with
+ processors that aren't supported by the intel_pstate driver
+ or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
+ no_hwp
+ Do not enable hardware P state control (HWP)
+ if available.
+ hwp_only
+ Only load intel_pstate on systems which support
+ hardware P state control (HWP) if available.
+ support_acpi_ppc
+ Enforce ACPI _PPC performance limits. If the Fixed ACPI
+ Description Table, specifies preferred power management
+ profile as "Enterprise Server" or "Performance Server",
+ then this feature is turned on by default.
+
+ intremap= [X86-64, Intel-IOMMU]
+ on enable Interrupt Remapping (default)
+ off disable Interrupt Remapping
+ nosid disable Source ID checking
+ no_x2apic_optout
+ BIOS x2APIC opt-out request will be ignored
+ nopost disable Interrupt Posting
+
+ iomem= Disable strict checking of access to MMIO memory
+ strict regions from userspace.
+ relaxed
+
+ iommu= [x86]
+ off
+ force
+ noforce
+ biomerge
+ panic
+ nopanic
+ merge
+ nomerge
+ forcesac
+ soft
+ pt [x86, IA-64]
+ nobypass [PPC/POWERNV]
+ Disable IOMMU bypass, using IOMMU for PCI devices.
+
+
+ io7= [HW] IO7 for Marvel based alpha systems
+ See comment before marvel_specify_io7 in
+ arch/alpha/kernel/core_marvel.c.
+
+ io_delay= [X86] I/O delay method
+ 0x80
+ Standard port 0x80 based delay
+ 0xed
+ Alternate port 0xed based delay (needed on some systems)
+ udelay
+ Simple two microseconds delay
+ none
+ No delay
+
+ ip= [IP_PNP]
+ See Documentation/filesystems/nfs/nfsroot.txt.
+
+ irqaffinity= [SMP] Set the default irq affinity mask
+ The argument is a cpu list, as described above.
+
+ irqfixup [HW]
+ When an interrupt is not handled search all handlers
+ for it. Intended to get systems with badly broken
+ firmware running.
+
+ irqpoll [HW]
+ When an interrupt is not handled search all handlers
+ for it. Also check all handlers each timer
+ interrupt. Intended to get systems with badly broken
+ firmware running.
+
+ isapnp= [ISAPNP]
+ Format: <RDP>,<reset>,<pci_scan>,<verbosity>
+
+ isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
+ The argument is a cpu list, as described above.
+
+ This option can be used to specify one or more CPUs
+ to isolate from the general SMP balancing and scheduling
+ algorithms. You can move a process onto or off an
+ "isolated" CPU via the CPU affinity syscalls or cpuset.
+ <cpu number> begins at 0 and the maximum value is
+ "number of CPUs in system - 1".
+
+ This option is the preferred way to isolate CPUs. The
+ alternative -- manually setting the CPU mask of all
+ tasks in the system -- can cause problems and
+ suboptimal load balancer performance.
+
+ iucv= [HW,NET]
+
+ ivrs_ioapic [HW,X86_64]
+ Provide an override to the IOAPIC-ID<->DEVICE-ID
+ mapping provided in the IVRS ACPI table. For
+ example, to map IOAPIC-ID decimal 10 to
+ PCI device 00:14.0 write the parameter as:
+ ivrs_ioapic[10]=00:14.0
+
+ ivrs_hpet [HW,X86_64]
+ Provide an override to the HPET-ID<->DEVICE-ID
+ mapping provided in the IVRS ACPI table. For
+ example, to map HPET-ID decimal 0 to
+ PCI device 00:14.0 write the parameter as:
+ ivrs_hpet[0]=00:14.0
+
+ ivrs_acpihid [HW,X86_64]
+ Provide an override to the ACPI-HID:UID<->DEVICE-ID
+ mapping provided in the IVRS ACPI table. For
+ example, to map UART-HID:UID AMD0020:0 to
+ PCI device 00:14.5 write the parameter as:
+ ivrs_acpihid[00:14.5]=AMD0020:0
+
+ js= [HW,JOY] Analog joystick
+ See Documentation/input/joystick.txt.
+
+ nokaslr [KNL]
+ When CONFIG_RANDOMIZE_BASE is set, this disables
+ kernel and module base offset ASLR (Address Space
+ Layout Randomization).
+
+ keepinitrd [HW,ARM]
+
+ kernelcore= [KNL,X86,IA-64,PPC]
+ Format: nn[KMGTPE] | "mirror"
+ This parameter
+ specifies the amount of memory usable by the kernel
+ for non-movable allocations. The requested amount is
+ spread evenly throughout all nodes in the system. The
+ remaining memory in each node is used for Movable
+ pages. In the event, a node is too small to have both
+ kernelcore and Movable pages, kernelcore pages will
+ take priority and other nodes will have a larger number
+ of Movable pages. The Movable zone is used for the
+ allocation of pages that may be reclaimed or moved
+ by the page migration subsystem. This means that
+ HugeTLB pages may not be allocated from this zone.
+ Note that allocations like PTEs-from-HighMem still
+ use the HighMem zone if it exists, and the Normal
+ zone if it does not.
+
+ Instead of specifying the amount of memory (nn[KMGTPE]),
+ you can specify "mirror" option. In case "mirror"
+ option is specified, mirrored (reliable) memory is used
+ for non-movable allocations and remaining memory is used
+ for Movable pages. nn[KMGTPE] and "mirror" are exclusive,
+ so you can NOT specify nn[KMGTPE] and "mirror" at the same
+ time.
+
+ kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
+ Format: <Controller#>[,poll interval]
+ The controller # is the number of the ehci usb debug
+ port as it is probed via PCI. The poll interval is
+ optional and is the number seconds in between
+ each poll cycle to the debug port in case you need
+ the functionality for interrupting the kernel with
+ gdb or control-c on the dbgp connection. When
+ not using this parameter you use sysrq-g to break into
+ the kernel debugger.
+
+ kgdboc= [KGDB,HW] kgdb over consoles.
+ Requires a tty driver that supports console polling,
+ or a supported polling keyboard driver (non-usb).
+ Serial only format: <serial_device>[,baud]
+ keyboard only format: kbd
+ keyboard and serial format: kbd,<serial_device>[,baud]
+ Optional Kernel mode setting:
+ kms, kbd format: kms,kbd
+ kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
+
+ kgdbwait [KGDB] Stop kernel execution and enter the
+ kernel debugger at the earliest opportunity.
+
+ kmac= [MIPS] korina ethernet MAC address.
+ Configure the RouterBoard 532 series on-chip
+ Ethernet adapter MAC address.
+
+ kmemleak= [KNL] Boot-time kmemleak enable/disable
+ Valid arguments: on, off
+ Default: on
+ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
+ the default is off.
+
+ kmemcheck= [X86] Boot-time kmemcheck enable/disable/one-shot mode
+ Valid arguments: 0, 1, 2
+ kmemcheck=0 (disabled)
+ kmemcheck=1 (enabled)
+ kmemcheck=2 (one-shot mode)
+ Default: 2 (one-shot mode)
+
+ kstack=N [X86] Print N words from the kernel stack
+ in oops dumps.
+
+ kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
+ Default is 0 (don't ignore, but inject #GP)
+
+ kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
+ KVM MMU at runtime.
+ Default is 0 (off)
+
+ kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
+ Default is 1 (enabled)
+
+ kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
+ for all guests.
+ Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
+
+ kvm-intel.ept= [KVM,Intel] Disable extended page tables
+ (virtualized MMU) support on capable Intel chips.
+ Default is 1 (enabled)
+
+ kvm-intel.emulate_invalid_guest_state=
+ [KVM,Intel] Enable emulation of invalid guest states
+ Default is 0 (disabled)
+
+ kvm-intel.flexpriority=
+ [KVM,Intel] Disable FlexPriority feature (TPR shadow).
+ Default is 1 (enabled)
+
+ kvm-intel.nested=
+ [KVM,Intel] Enable VMX nesting (nVMX).
+ Default is 0 (disabled)
+
+ kvm-intel.unrestricted_guest=
+ [KVM,Intel] Disable unrestricted guest feature
+ (virtualized real and unpaged mode) on capable
+ Intel chips. Default is 1 (enabled)
+
+ kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
+ feature (tagged TLBs) on capable Intel chips.
+ Default is 1 (enabled)
+
+ l2cr= [PPC]
+
+ l3cr= [PPC]
+
+ lapic [X86-32,APIC] Enable the local APIC even if BIOS
+ disabled it.
+
+ lapic= [x86,APIC] "notscdeadline" Do not use TSC deadline
+ value for LAPIC timer one-shot implementation. Default
+ back to the programmable timer unit in the LAPIC.
+
+ lapic_timer_c2_ok [X86,APIC] trust the local apic timer
+ in C2 power state.
+
+ libata.dma= [LIBATA] DMA control
+ libata.dma=0 Disable all PATA and SATA DMA
+ libata.dma=1 PATA and SATA Disk DMA only
+ libata.dma=2 ATAPI (CDROM) DMA only
+ libata.dma=4 Compact Flash DMA only
+ Combinations also work, so libata.dma=3 enables DMA
+ for disks and CDROMs, but not CFs.
+
+ libata.ignore_hpa= [LIBATA] Ignore HPA limit
+ libata.ignore_hpa=0 keep BIOS limits (default)
+ libata.ignore_hpa=1 ignore limits, using full disk
+
+ libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
+ when set.
+ Format: <int>
+
+ libata.force= [LIBATA] Force configurations. The format is comma
+ separated list of "[ID:]VAL" where ID is
+ PORT[.DEVICE]. PORT and DEVICE are decimal numbers
+ matching port, link or device. Basically, it matches
+ the ATA ID string printed on console by libata. If
+ the whole ID part is omitted, the last PORT and DEVICE
+ values are used. If ID hasn't been specified yet, the
+ configuration applies to all ports, links and devices.
+
+ If only DEVICE is omitted, the parameter applies to
+ the port and all links and devices behind it. DEVICE
+ number of 0 either selects the first device or the
+ first fan-out link behind PMP device. It does not
+ select the host link. DEVICE number of 15 selects the
+ host link and device attached to it.
+
+ The VAL specifies the configuration to force. As long
+ as there's no ambiguity shortcut notation is allowed.
+ For example, both 1.5 and 1.5G would work for 1.5Gbps.
+ The following configurations can be forced.
+
+ * Cable type: 40c, 80c, short40c, unk, ign or sata.
+ Any ID with matching PORT is used.
+
+ * SATA link speed limit: 1.5Gbps or 3.0Gbps.
+
+ * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
+ udma[/][16,25,33,44,66,100,133] notation is also
+ allowed.
+
+ * [no]ncq: Turn on or off NCQ.
+
+ * [no]ncqtrim: Turn off queued DSM TRIM.
+
+ * nohrst, nosrst, norst: suppress hard, soft
+ and both resets.
+
+ * rstonce: only attempt one reset during
+ hot-unplug link recovery
+
+ * dump_id: dump IDENTIFY data.
+
+ * atapi_dmadir: Enable ATAPI DMADIR bridge support
+
+ * disable: Disable this device.
+
+ If there are multiple matching configurations changing
+ the same attribute, the last one is used.
+
+ memblock=debug [KNL] Enable memblock debug messages.
+
+ load_ramdisk= [RAM] List of ramdisks to load from floppy
+ See Documentation/blockdev/ramdisk.txt.
+
+ lockd.nlm_grace_period=P [NFS] Assign grace period.
+ Format: <integer>
+
+ lockd.nlm_tcpport=N [NFS] Assign TCP port.
+ Format: <integer>
+
+ lockd.nlm_timeout=T [NFS] Assign timeout value.
+ Format: <integer>
+
+ lockd.nlm_udpport=M [NFS] Assign UDP port.
+ Format: <integer>
+
+ locktorture.nreaders_stress= [KNL]
+ Set the number of locking read-acquisition kthreads.
+ Defaults to being automatically set based on the
+ number of online CPUs.
+
+ locktorture.nwriters_stress= [KNL]
+ Set the number of locking write-acquisition kthreads.
+
+ locktorture.onoff_holdoff= [KNL]
+ Set time (s) after boot for CPU-hotplug testing.
+
+ locktorture.onoff_interval= [KNL]
+ Set time (s) between CPU-hotplug operations, or
+ zero to disable CPU-hotplug testing.
+
+ locktorture.shuffle_interval= [KNL]
+ Set task-shuffle interval (jiffies). Shuffling
+ tasks allows some CPUs to go into dyntick-idle
+ mode during the locktorture test.
+
+ locktorture.shutdown_secs= [KNL]
+ Set time (s) after boot system shutdown. This
+ is useful for hands-off automated testing.
+
+ locktorture.stat_interval= [KNL]
+ Time (s) between statistics printk()s.
+
+ locktorture.stutter= [KNL]
+ Time (s) to stutter testing, for example,
+ specifying five seconds causes the test to run for
+ five seconds, wait for five seconds, and so on.
+ This tests the locking primitive's ability to
+ transition abruptly to and from idle.
+
+ locktorture.torture_runnable= [BOOT]
+ Start locktorture running at boot time.
+
+ locktorture.torture_type= [KNL]
+ Specify the locking implementation to test.
+
+ locktorture.verbose= [KNL]
+ Enable additional printk() statements.
+
+ logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
+ Format: <irq>
+
+ loglevel= All Kernel Messages with a loglevel smaller than the
+ console loglevel will be printed to the console. It can
+ also be changed with klogd or other programs. The
+ loglevels are defined as follows:
+
+ 0 (KERN_EMERG) system is unusable
+ 1 (KERN_ALERT) action must be taken immediately
+ 2 (KERN_CRIT) critical conditions
+ 3 (KERN_ERR) error conditions
+ 4 (KERN_WARNING) warning conditions
+ 5 (KERN_NOTICE) normal but significant condition
+ 6 (KERN_INFO) informational
+ 7 (KERN_DEBUG) debug-level messages
+
+ log_buf_len=n[KMG] Sets the size of the printk ring buffer,
+ in bytes. n must be a power of two and greater
+ than the minimal size. The minimal size is defined
+ by LOG_BUF_SHIFT kernel config parameter. There is
+ also CONFIG_LOG_CPU_MAX_BUF_SHIFT config parameter
+ that allows to increase the default size depending on
+ the number of CPUs. See init/Kconfig for more details.
+
+ logo.nologo [FB] Disables display of the built-in Linux logo.
+ This may be used to provide more screen space for
+ kernel log messages and is useful when debugging
+ kernel boot problems.
+
+ lp=0 [LP] Specify parallel ports to use, e.g,
+ lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
+ lp=reset first parallel port). 'lp=0' disables the
+ lp=auto printer driver. 'lp=reset' (which can be
+ specified in addition to the ports) causes
+ attached printers to be reset. Using
+ lp=port1,port2,... specifies the parallel ports
+ to associate lp devices with, starting with
+ lp0. A port specification may be 'none' to skip
+ that lp device, or a parport name such as
+ 'parport0'. Specifying 'lp=auto' instead of a
+ port specification list means that device IDs
+ from each port should be examined, to see if
+ an IEEE 1284-compliant printer is attached; if
+ so, the driver will manage that printer.
+ See also header of drivers/char/lp.c.
+
+ lpj=n [KNL]
+ Sets loops_per_jiffy to given constant, thus avoiding
+ time-consuming boot-time autodetection (up to 250 ms per
+ CPU). 0 enables autodetection (default). To determine
+ the correct value for your kernel, boot with normal
+ autodetection and see what value is printed. Note that
+ on SMP systems the preset will be applied to all CPUs,
+ which is likely to cause problems if your CPUs need
+ significantly divergent settings. An incorrect value
+ will cause delays in the kernel to be wrong, leading to
+ unpredictable I/O errors and other breakage. Although
+ unlikely, in the extreme case this might damage your
+ hardware.
+
+ ltpc= [NET]
+ Format: <io>,<irq>,<dma>
+
+ machvec= [IA-64] Force the use of a particular machine-vector
+ (machvec) in a generic kernel.
+ Example: machvec=hpzx1_swiotlb
+
+ machtype= [Loongson] Share the same kernel image file between different
+ yeeloong laptop.
+ Example: machtype=lemote-yeeloong-2f-7inch
+
+ max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
+ than or equal to this physical address is ignored.
+
+ maxcpus= [SMP] Maximum number of processors that an SMP kernel
+ will bring up during bootup. maxcpus=n : n >= 0 limits
+ the kernel to bring up 'n' processors. Surely after
+ bootup you can bring up the other plugged cpu by executing
+ "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
+ only takes effect during system bootup.
+ While n=0 is a special case, it is equivalent to "nosmp",
+ which also disables the IO APIC.
+
+ max_loop= [LOOP] The number of loop block devices that get
+ (loop.max_loop) unconditionally pre-created at init time. The default
+ number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
+ of statically allocating a predefined number, loop
+ devices can be requested on-demand with the
+ /dev/loop-control interface.
+
+ mce [X86-32] Machine Check Exception
+
+ mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
+
+ md= [HW] RAID subsystems devices and level
+ See Documentation/md.txt.
+
+ mdacon= [MDA]
+ Format: <first>,<last>
+ Specifies range of consoles to be captured by the MDA.
+
+ mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
+ Amount of memory to be used when the kernel is not able
+ to see the whole system memory or for test.
+ [X86] Work as limiting max address. Use together
+ with memmap= to avoid physical address space collisions.
+ Without memmap= PCI devices could be placed at addresses
+ belonging to unused RAM.
+
+ mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
+ memory.
+
+ memchunk=nn[KMG]
+ [KNL,SH] Allow user to override the default size for
+ per-device physically contiguous DMA buffers.
+
+ memhp_default_state=online/offline
+ [KNL] Set the initial state for the memory hotplug
+ onlining policy. If not specified, the default value is
+ set according to the
+ CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config
+ option.
+ See Documentation/memory-hotplug.txt.
+
+ memmap=exactmap [KNL,X86] Enable setting of an exact
+ E820 memory map, as specified by the user.
+ Such memmap=exactmap lines can be constructed based on
+ BIOS output or other requirements. See the memmap=nn@ss
+ option description.
+
+ memmap=nn[KMG]@ss[KMG]
+ [KNL] Force usage of a specific region of memory.
+ Region of memory to be used is from ss to ss+nn.
+
+ memmap=nn[KMG]#ss[KMG]
+ [KNL,ACPI] Mark specific memory as ACPI data.
+ Region of memory to be marked is from ss to ss+nn.
+
+ memmap=nn[KMG]$ss[KMG]
+ [KNL,ACPI] Mark specific memory as reserved.
+ Region of memory to be reserved is from ss to ss+nn.
+ Example: Exclude memory from 0x18690000-0x1869ffff
+ memmap=64K$0x18690000
+ or
+ memmap=0x10000$0x18690000
+
+ memmap=nn[KMG]!ss[KMG]
+ [KNL,X86] Mark specific memory as protected.
+ Region of memory to be used, from ss to ss+nn.
+ The memory region may be marked as e820 type 12 (0xc)
+ and is NVDIMM or ADR memory.
+
+ memory_corruption_check=0/1 [X86]
+ Some BIOSes seem to corrupt the first 64k of
+ memory when doing things like suspend/resume.
+ Setting this option will scan the memory
+ looking for corruption. Enabling this will
+ both detect corruption and prevent the kernel
+ from using the memory being corrupted.
+ However, its intended as a diagnostic tool; if
+ repeatable BIOS-originated corruption always
+ affects the same memory, you can use memmap=
+ to prevent the kernel from using that memory.
+
+ memory_corruption_check_size=size [X86]
+ By default it checks for corruption in the low
+ 64k, making this memory unavailable for normal
+ use. Use this parameter to scan for
+ corruption in more or less memory.
+
+ memory_corruption_check_period=seconds [X86]
+ By default it checks for corruption every 60
+ seconds. Use this parameter to check at some
+ other rate. 0 disables periodic checking.
+
+ memtest= [KNL,X86,ARM] Enable memtest
+ Format: <integer>
+ default : 0 <disable>
+ Specifies the number of memtest passes to be
+ performed. Each pass selects another test
+ pattern from a given set of patterns. Memtest
+ fills the memory with this pattern, validates
+ memory contents and reserves bad memory
+ regions that are detected.
+
+ meye.*= [HW] Set MotionEye Camera parameters
+ See Documentation/video4linux/meye.txt.
+
+ mfgpt_irq= [IA-32] Specify the IRQ to use for the
+ Multi-Function General Purpose Timers on AMD Geode
+ platforms.
+
+ mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
+ the BIOS has incorrectly applied a workaround. TinyBIOS
+ version 0.98 is known to be affected, 0.99 fixes the
+ problem by letting the user disable the workaround.
+
+ mga= [HW,DRM]
+
+ min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
+ physical address is ignored.
+
+ mini2440= [ARM,HW,KNL]
+ Format:[0..2][b][c][t]
+ Default: "0tb"
+ MINI2440 configuration specification:
+ 0 - The attached screen is the 3.5" TFT
+ 1 - The attached screen is the 7" TFT
+ 2 - The VGA Shield is attached (1024x768)
+ Leaving out the screen size parameter will not load
+ the TFT driver, and the framebuffer will be left
+ unconfigured.
+ b - Enable backlight. The TFT backlight pin will be
+ linked to the kernel VESA blanking code and a GPIO
+ LED. This parameter is not necessary when using the
+ VGA shield.
+ c - Enable the s3c camera interface.
+ t - Reserved for enabling touchscreen support. The
+ touchscreen support is not enabled in the mainstream
+ kernel as of 2.6.30, a preliminary port can be found
+ in the "bleeding edge" mini2440 support kernel at
+ http://repo.or.cz/w/linux-2.6/mini2440.git
+
+ mminit_loglevel=
+ [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
+ parameter allows control of the logging verbosity for
+ the additional memory initialisation checks. A value
+ of 0 disables mminit logging and a level of 4 will
+ log everything. Information is printed at KERN_DEBUG
+ so loglevel=8 may also need to be specified.
+
+ module.sig_enforce
+ [KNL] When CONFIG_MODULE_SIG is set, this means that
+ modules without (valid) signatures will fail to load.
+ Note that if CONFIG_MODULE_SIG_FORCE is set, that
+ is always true, so this option does nothing.
+
+ module_blacklist= [KNL] Do not load a comma-separated list of
+ modules. Useful for debugging problem modules.
+
+ mousedev.tap_time=
+ [MOUSE] Maximum time between finger touching and
+ leaving touchpad surface for touch to be considered
+ a tap and be reported as a left button click (for
+ touchpads working in absolute mode only).
+ Format: <msecs>
+ mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
+ reporting absolute coordinates, such as tablets
+ mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
+ reporting absolute coordinates, such as tablets
+
+ movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
+ is similar to kernelcore except it specifies the
+ amount of memory used for migratable allocations.
+ If both kernelcore and movablecore is specified,
+ then kernelcore will be at *least* the specified
+ value but may be more. If movablecore on its own
+ is specified, the administrator must be careful
+ that the amount of memory usable for all allocations
+ is not too small.
+
+ movable_node [KNL,X86] Boot-time switch to enable the effects
+ of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
+
+ MTD_Partition= [MTD]
+ Format: <name>,<region-number>,<size>,<offset>
+
+ MTD_Region= [MTD] Format:
+ <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
+
+ mtdparts= [MTD]
+ See drivers/mtd/cmdlinepart.c.
+
+ multitce=off [PPC] This parameter disables the use of the pSeries
+ firmware feature for updating multiple TCE entries
+ at a time.
+
+ onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
+
+ Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
+
+ boundary - index of last SLC block on Flex-OneNAND.
+ The remaining blocks are configured as MLC blocks.
+ lock - Configure if Flex-OneNAND boundary should be locked.
+ Once locked, the boundary cannot be changed.
+ 1 indicates lock status, 0 indicates unlock status.
+
+ mtdset= [ARM]
+ ARM/S3C2412 JIVE boot control
+
+ See arch/arm/mach-s3c2412/mach-jive.c
+
+ mtouchusb.raw_coordinates=
+ [HW] Make the MicroTouch USB driver use raw coordinates
+ ('y', default) or cooked coordinates ('n')
+
+ mtrr_chunk_size=nn[KMG] [X86]
+ used for mtrr cleanup. It is largest continuous chunk
+ that could hold holes aka. UC entries.
+
+ mtrr_gran_size=nn[KMG] [X86]
+ Used for mtrr cleanup. It is granularity of mtrr block.
+ Default is 1.
+ Large value could prevent small alignment from
+ using up MTRRs.
+
+ mtrr_spare_reg_nr=n [X86]
+ Format: <integer>
+ Range: 0,7 : spare reg number
+ Default : 1
+ Used for mtrr cleanup. It is spare mtrr entries number.
+ Set to 2 or more if your graphical card needs more.
+
+ n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
+
+ netdev= [NET] Network devices parameters
+ Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
+ Note that mem_start is often overloaded to mean
+ something different and driver-specific.
+ This usage is only documented in each driver source
+ file if at all.
+
+ nf_conntrack.acct=
+ [NETFILTER] Enable connection tracking flow accounting
+ 0 to disable accounting
+ 1 to enable accounting
+ Default value is 0.
+
+ nfsaddrs= [NFS] Deprecated. Use ip= instead.
+ See Documentation/filesystems/nfs/nfsroot.txt.
+
+ nfsroot= [NFS] nfs root filesystem for disk-less boxes.
+ See Documentation/filesystems/nfs/nfsroot.txt.
+
+ nfsrootdebug [NFS] enable nfsroot debugging messages.
+ See Documentation/filesystems/nfs/nfsroot.txt.
+
+ nfs.callback_nr_threads=
+ [NFSv4] set the total number of threads that the
+ NFS client will assign to service NFSv4 callback
+ requests.
+
+ nfs.callback_tcpport=
+ [NFS] set the TCP port on which the NFSv4 callback
+ channel should listen.
+
+ nfs.cache_getent=
+ [NFS] sets the pathname to the program which is used
+ to update the NFS client cache entries.
+
+ nfs.cache_getent_timeout=
+ [NFS] sets the timeout after which an attempt to
+ update a cache entry is deemed to have failed.
+
+ nfs.idmap_cache_timeout=
+ [NFS] set the maximum lifetime for idmapper cache
+ entries.
+
+ nfs.enable_ino64=
+ [NFS] enable 64-bit inode numbers.
+ If zero, the NFS client will fake up a 32-bit inode
+ number for the readdir() and stat() syscalls instead
+ of returning the full 64-bit number.
+ The default is to return 64-bit inode numbers.
+
+ nfs.max_session_cb_slots=
+ [NFSv4.1] Sets the maximum number of session
+ slots the client will assign to the callback
+ channel. This determines the maximum number of
+ callbacks the client will process in parallel for
+ a particular server.
+
+ nfs.max_session_slots=
+ [NFSv4.1] Sets the maximum number of session slots
+ the client will attempt to negotiate with the server.
+ This limits the number of simultaneous RPC requests
+ that the client can send to the NFSv4.1 server.
+ Note that there is little point in setting this
+ value higher than the max_tcp_slot_table_limit.
+
+ nfs.nfs4_disable_idmapping=
+ [NFSv4] When set to the default of '1', this option
+ ensures that both the RPC level authentication
+ scheme and the NFS level operations agree to use
+ numeric uids/gids if the mount is using the
+ 'sec=sys' security flavour. In effect it is
+ disabling idmapping, which can make migration from
+ legacy NFSv2/v3 systems to NFSv4 easier.
+ Servers that do not support this mode of operation
+ will be autodetected by the client, and it will fall
+ back to using the idmapper.
+ To turn off this behaviour, set the value to '0'.
+ nfs.nfs4_unique_id=
+ [NFS4] Specify an additional fixed unique ident-
+ ification string that NFSv4 clients can insert into
+ their nfs_client_id4 string. This is typically a
+ UUID that is generated at system install time.
+
+ nfs.send_implementation_id =
+ [NFSv4.1] Send client implementation identification
+ information in exchange_id requests.
+ If zero, no implementation identification information
+ will be sent.
+ The default is to send the implementation identification
+ information.
+
+ nfs.recover_lost_locks =
+ [NFSv4] Attempt to recover locks that were lost due
+ to a lease timeout on the server. Please note that
+ doing this risks data corruption, since there are
+ no guarantees that the file will remain unchanged
+ after the locks are lost.
+ If you want to enable the kernel legacy behaviour of
+ attempting to recover these locks, then set this
+ parameter to '1'.
+ The default parameter value of '0' causes the kernel
+ not to attempt recovery of lost locks.
+
+ nfs4.layoutstats_timer =
+ [NFSv4.2] Change the rate at which the kernel sends
+ layoutstats to the pNFS metadata server.
+
+ Setting this to value to 0 causes the kernel to use
+ whatever value is the default set by the layout
+ driver. A non-zero value sets the minimum interval
+ in seconds between layoutstats transmissions.
+
+ nfsd.nfs4_disable_idmapping=
+ [NFSv4] When set to the default of '1', the NFSv4
+ server will return only numeric uids and gids to
+ clients using auth_sys, and will accept numeric uids
+ and gids from such clients. This is intended to ease
+ migration from NFSv2/v3.
+
+ objlayoutdriver.osd_login_prog=
+ [NFS] [OBJLAYOUT] sets the pathname to the program which
+ is used to automatically discover and login into new
+ osd-targets. Please see:
+ Documentation/filesystems/pnfs.txt for more explanations
+
+ nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
+ when a NMI is triggered.
+ Format: [state][,regs][,debounce][,die]
+
+ nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
+ Format: [panic,][nopanic,][num]
+ Valid num: 0 or 1
+ 0 - turn hardlockup detector in nmi_watchdog off
+ 1 - turn hardlockup detector in nmi_watchdog on
+ When panic is specified, panic when an NMI watchdog
+ timeout occurs (or 'nopanic' to override the opposite
+ default). To disable both hard and soft lockup detectors,
+ please see 'nowatchdog'.
+ This is useful when you use a panic=... timeout and
+ need the box quickly up again.
+
+ netpoll.carrier_timeout=
+ [NET] Specifies amount of time (in seconds) that
+ netpoll should wait for a carrier. By default netpoll
+ waits 4 seconds.
+
+ no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
+ emulation library even if a 387 maths coprocessor
+ is present.
+
+ no_console_suspend
+ [HW] Never suspend the console
+ Disable suspending of consoles during suspend and
+ hibernate operations. Once disabled, debugging
+ messages can reach various consoles while the rest
+ of the system is being put to sleep (ie, while
+ debugging driver suspend/resume hooks). This may
+ not work reliably with all consoles, but is known
+ to work with serial and VGA consoles.
+ To facilitate more flexible debugging, we also add
+ console_suspend, a printk module parameter to control
+ it. Users could use console_suspend (usually
+ /sys/module/printk/parameters/console_suspend) to
+ turn on/off it dynamically.
+
+ noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
+ caches in the slab allocator. Saves per-node memory,
+ but will impact performance.
+
+ noalign [KNL,ARM]
+
+ noapic [SMP,APIC] Tells the kernel to not make use of any
+ IOAPICs that may be present in the system.
+
+ noautogroup Disable scheduler automatic task group creation.
+
+ nobats [PPC] Do not use BATs for mapping kernel lowmem
+ on "Classic" PPC cores.
+
+ nocache [ARM]
+
+ noclflush [BUGS=X86] Don't use the CLFLUSH instruction
+
+ nodelayacct [KNL] Disable per-task delay accounting
+
+ nodsp [SH] Disable hardware DSP at boot time.
+
+ noefi Disable EFI runtime services support.
+
+ noexec [IA-64]
+
+ noexec [X86]
+ On X86-32 available only on PAE configured kernels.
+ noexec=on: enable non-executable mappings (default)
+ noexec=off: disable non-executable mappings
+
+ nosmap [X86]
+ Disable SMAP (Supervisor Mode Access Prevention)
+ even if it is supported by processor.
+
+ nosmep [X86]
+ Disable SMEP (Supervisor Mode Execution Prevention)
+ even if it is supported by processor.
+
+ noexec32 [X86-64]
+ This affects only 32-bit executables.
+ noexec32=on: enable non-executable mappings (default)
+ read doesn't imply executable mappings
+ noexec32=off: disable non-executable mappings
+ read implies executable mappings
+
+ nofpu [MIPS,SH] Disable hardware FPU at boot time.
+
+ nofxsr [BUGS=X86-32] Disables x86 floating point extended
+ register save and restore. The kernel will only save
+ legacy floating-point registers on task switch.
+
+ nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
+
+ nosmt [KNL,S390] Disable symmetric multithreading (SMT).
+ Equivalent to smt=1.
+
+ noxsave [BUGS=X86] Disables x86 extended register state save
+ and restore using xsave. The kernel will fallback to
+ enabling legacy floating-point and sse state.
+
+ noxsaveopt [X86] Disables xsaveopt used in saving x86 extended
+ register states. The kernel will fall back to use
+ xsave to save the states. By using this parameter,
+ performance of saving the states is degraded because
+ xsave doesn't support modified optimization while
+ xsaveopt supports it on xsaveopt enabled systems.
+
+ noxsaves [X86] Disables xsaves and xrstors used in saving and
+ restoring x86 extended register state in compacted
+ form of xsave area. The kernel will fall back to use
+ xsaveopt and xrstor to save and restore the states
+ in standard form of xsave area. By using this
+ parameter, xsave area per process might occupy more
+ memory on xsaves enabled systems.
+
+ nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
+ wfi(ARM) instruction doesn't work correctly and not to
+ use it. This is also useful when using JTAG debugger.
+
+ no_file_caps Tells the kernel not to honor file capabilities. The
+ only way then for a file to be executed with privilege
+ is to be setuid root or executed by root.
+
+ nohalt [IA-64] Tells the kernel not to use the power saving
+ function PAL_HALT_LIGHT when idle. This increases
+ power-consumption. On the positive side, it reduces
+ interrupt wake-up latency, which may improve performance
+ in certain environments such as networked servers or
+ real-time systems.
+
+ nohibernate [HIBERNATION] Disable hibernation and resume.
+
+ nohz= [KNL] Boottime enable/disable dynamic ticks
+ Valid arguments: on, off
+ Default: on
+
+ nohz_full= [KNL,BOOT]
+ The argument is a cpu list, as described above.
+ In kernels built with CONFIG_NO_HZ_FULL=y, set
+ the specified list of CPUs whose tick will be stopped
+ whenever possible. The boot CPU will be forced outside
+ the range to maintain the timekeeping.
+ The CPUs in this range must also be included in the
+ rcu_nocbs= set.
+
+ noiotrap [SH] Disables trapped I/O port accesses.
+
+ noirqdebug [X86-32] Disables the code which attempts to detect and
+ disable unhandled interrupt sources.
+
+ no_timer_check [X86,APIC] Disables the code which tests for
+ broken timer IRQ sources.
+
+ noisapnp [ISAPNP] Disables ISA PnP code.
+
+ noinitrd [RAM] Tells the kernel not to load any configured
+ initial RAM disk.
+
+ nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
+ remapping.
+ [Deprecated - use intremap=off]
+
+ nointroute [IA-64]
+
+ noinvpcid [X86] Disable the INVPCID cpu feature.
+
+ nojitter [IA-64] Disables jitter checking for ITC timers.
+
+ no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
+
+ no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
+ fault handling.
+
+ no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
+ steal time is computed, but won't influence scheduler
+ behaviour
+
+ nolapic [X86-32,APIC] Do not enable or use the local APIC.
+
+ nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
+
+ noltlbs [PPC] Do not use large page/tlb entries for kernel
+ lowmem mapping on PPC40x and PPC8xx
+
+ nomca [IA-64] Disable machine check abort handling
+
+ nomce [X86-32] Disable Machine Check Exception
+
+ nomfgpt [X86-32] Disable Multi-Function General Purpose
+ Timer usage (for AMD Geode machines).
+
+ nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
+ shutdown the other cpus. Instead use the REBOOT_VECTOR
+ irq.
+
+ nomodule Disable module load
+
+ nopat [X86] Disable PAT (page attribute table extension of
+ pagetables) support.
+
+ norandmaps Don't use address space randomization. Equivalent to
+ echo 0 > /proc/sys/kernel/randomize_va_space
+
+ noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
+
+ noreplace-smp [X86-32,SMP] Don't replace SMP instructions
+ with UP alternatives
+
+ nordrand [X86] Disable kernel use of the RDRAND and
+ RDSEED instructions even if they are supported
+ by the processor. RDRAND and RDSEED are still
+ available to user space applications.
+
+ noresume [SWSUSP] Disables resume and restores original swap
+ space.
+
+ no-scroll [VGA] Disables scrollback.
+ This is required for the Braillex ib80-piezo Braille
+ reader made by F.H. Papenmeier (Germany).
+
+ nosbagart [IA-64]
+
+ nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
+
+ nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
+ and disable the IO APIC. legacy for "maxcpus=0".
+
+ nosoftlockup [KNL] Disable the soft-lockup detector.
+
+ nosync [HW,M68K] Disables sync negotiation for all devices.
+
+ notsc [BUGS=X86-32] Disable Time Stamp Counter
+
+ nowatchdog [KNL] Disable both lockup detectors, i.e.
+ soft-lockup and NMI watchdog (hard-lockup).
+
+ nowb [ARM]
+
+ nox2apic [X86-64,APIC] Do not enable x2APIC mode.
+
+ cpu0_hotplug [X86] Turn on CPU0 hotplug feature when
+ CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off.
+ Some features depend on CPU0. Known dependencies are:
+ 1. Resume from suspend/hibernate depends on CPU0.
+ Suspend/hibernate will fail if CPU0 is offline and you
+ need to online CPU0 before suspend/hibernate.
+ 2. PIC interrupts also depend on CPU0. CPU0 can't be
+ removed if a PIC interrupt is detected.
+ It's said poweroff/reboot may depend on CPU0 on some
+ machines although I haven't seen such issues so far
+ after CPU0 is offline on a few tested machines.
+ If the dependencies are under your control, you can
+ turn on cpu0_hotplug.
+
+ nptcg= [IA-64] Override max number of concurrent global TLB
+ purges which is reported from either PAL_VM_SUMMARY or
+ SAL PALO.
+
+ nr_cpus= [SMP] Maximum number of processors that an SMP kernel
+ could support. nr_cpus=n : n >= 1 limits the kernel to
+ support 'n' processors. It could be larger than the
+ number of already plugged CPU during bootup, later in
+ runtime you can physically add extra cpu until it reaches
+ n. So during boot up some boot time memory for per-cpu
+ variables need be pre-allocated for later physical cpu
+ hot plugging.
+
+ nr_uarts= [SERIAL] maximum number of UARTs to be registered.
+
+ numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing.
+ Allowed values are enable and disable
+
+ numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
+ one of ['zone', 'node', 'default'] can be specified
+ This can be set from sysctl after boot.
+ See Documentation/sysctl/vm.txt for details.
+
+ ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
+ See Documentation/debugging-via-ohci1394.txt for more
+ info.
+
+ olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
+ Rather than timing out after 20 ms if an EC
+ command is not properly ACKed, override the length
+ of the timeout. We have interrupts disabled while
+ waiting for the ACK, so if this is set too high
+ interrupts *may* be lost!
+
+ omap_mux= [OMAP] Override bootloader pin multiplexing.
+ Format: <mux_mode0.mode_name=value>...
+ For example, to override I2C bus2:
+ omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
+
+ oprofile.timer= [HW]
+ Use timer interrupt instead of performance counters
+
+ oprofile.cpu_type= Force an oprofile cpu type
+ This might be useful if you have an older oprofile
+ userland or if you want common events.
+ Format: { arch_perfmon }
+ arch_perfmon: [X86] Force use of architectural
+ perfmon on Intel CPUs instead of the
+ CPU specific event set.
+ timer: [X86] Force use of architectural NMI
+ timer mode (see also oprofile.timer
+ for generic hr timer mode)
+
+ oops=panic Always panic on oopses. Default is to just kill the
+ process, but there is a small probability of
+ deadlocking the machine.
+ This will also cause panics on machine check exceptions.
+ Useful together with panic=30 to trigger a reboot.
+
+ OSS [HW,OSS]
+ See Documentation/sound/oss/oss-parameters.txt
+
+ page_owner= [KNL] Boot-time page_owner enabling option.
+ Storage of the information about who allocated
+ each page is disabled in default. With this switch,
+ we can turn it on.
+ on: enable the feature
+
+ page_poison= [KNL] Boot-time parameter changing the state of
+ poisoning on the buddy allocator.
+ off: turn off poisoning
+ on: turn on poisoning
+
+ panic= [KNL] Kernel behaviour on panic: delay <timeout>
+ timeout > 0: seconds before rebooting
+ timeout = 0: wait forever
+ timeout < 0: reboot immediately
+ Format: <timeout>
+
+ panic_on_warn panic() instead of WARN(). Useful to cause kdump
+ on a WARN().
+
+ crash_kexec_post_notifiers
+ Run kdump after running panic-notifiers and dumping
+ kmsg. This only for the users who doubt kdump always
+ succeeds in any situation.
+ Note that this also increases risks of kdump failure,
+ because some panic notifiers can make the crashed
+ kernel more unstable.
+
+ parkbd.port= [HW] Parallel port number the keyboard adapter is
+ connected to, default is 0.
+ Format: <parport#>
+ parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
+ 0 for XT, 1 for AT (default is AT).
+ Format: <mode>
+
+ parport= [HW,PPT] Specify parallel ports. 0 disables.
+ Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
+ Use 'auto' to force the driver to use any
+ IRQ/DMA settings detected (the default is to
+ ignore detected IRQ/DMA settings because of
+ possible conflicts). You can specify the base
+ address, IRQ, and DMA settings; IRQ and DMA
+ should be numbers, or 'auto' (for using detected
+ settings on that particular port), or 'nofifo'
+ (to avoid using a FIFO even if it is detected).
+ Parallel ports are assigned in the order they
+ are specified on the command line, starting
+ with parport0.
+
+ parport_init_mode= [HW,PPT]
+ Configure VIA parallel port to operate in
+ a specific mode. This is necessary on Pegasos
+ computer where firmware has no options for setting
+ up parallel port mode and sets it to spp.
+ Currently this function knows 686a and 8231 chips.
+ Format: [spp|ps2|epp|ecp|ecpepp]
+
+ pause_on_oops=
+ Halt all CPUs after the first oops has been printed for
+ the specified number of seconds. This is to be used if
+ your oopses keep scrolling off the screen.
+
+ pcbit= [HW,ISDN]
+
+ pcd. [PARIDE]
+ See header of drivers/block/paride/pcd.c.
+ See also Documentation/blockdev/paride.txt.
+
+ pci=option[,option...] [PCI] various PCI subsystem options:
+ earlydump [X86] dump PCI config space before the kernel
+ changes anything
+ off [X86] don't probe for the PCI bus
+ bios [X86-32] force use of PCI BIOS, don't access
+ the hardware directly. Use this if your machine
+ has a non-standard PCI host bridge.
+ nobios [X86-32] disallow use of PCI BIOS, only direct
+ hardware access methods are allowed. Use this
+ if you experience crashes upon bootup and you
+ suspect they are caused by the BIOS.
+ conf1 [X86] Force use of PCI Configuration Access
+ Mechanism 1 (config address in IO port 0xCF8,
+ data in IO port 0xCFC, both 32-bit).
+ conf2 [X86] Force use of PCI Configuration Access
+ Mechanism 2 (IO port 0xCF8 is an 8-bit port for
+ the function, IO port 0xCFA, also 8-bit, sets
+ bus number. The config space is then accessed
+ through ports 0xC000-0xCFFF).
+ See http://wiki.osdev.org/PCI for more info
+ on the configuration access mechanisms.
+ noaer [PCIE] If the PCIEAER kernel config parameter is
+ enabled, this kernel boot option can be used to
+ disable the use of PCIE advanced error reporting.
+ nodomains [PCI] Disable support for multiple PCI
+ root domains (aka PCI segments, in ACPI-speak).
+ nommconf [X86] Disable use of MMCONFIG for PCI
+ Configuration
+ check_enable_amd_mmconf [X86] check for and enable
+ properly configured MMIO access to PCI
+ config space on AMD family 10h CPU
+ nomsi [MSI] If the PCI_MSI kernel config parameter is
+ enabled, this kernel boot option can be used to
+ disable the use of MSI interrupts system-wide.
+ noioapicquirk [APIC] Disable all boot interrupt quirks.
+ Safety option to keep boot IRQs enabled. This
+ should never be necessary.
+ ioapicreroute [APIC] Enable rerouting of boot IRQs to the
+ primary IO-APIC for bridges that cannot disable
+ boot IRQs. This fixes a source of spurious IRQs
+ when the system masks IRQs.
+ noioapicreroute [APIC] Disable workaround that uses the
+ boot IRQ equivalent of an IRQ that connects to
+ a chipset where boot IRQs cannot be disabled.
+ The opposite of ioapicreroute.
+ biosirq [X86-32] Use PCI BIOS calls to get the interrupt
+ routing table. These calls are known to be buggy
+ on several machines and they hang the machine
+ when used, but on other computers it's the only
+ way to get the interrupt routing table. Try
+ this option if the kernel is unable to allocate
+ IRQs or discover secondary PCI buses on your
+ motherboard.
+ rom [X86] Assign address space to expansion ROMs.
+ Use with caution as certain devices share
+ address decoders between ROMs and other
+ resources.
+ norom [X86] Do not assign address space to
+ expansion ROMs that do not already have
+ BIOS assigned address ranges.
+ nobar [X86] Do not assign address space to the
+ BARs that weren't assigned by the BIOS.
+ irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
+ assigned automatically to PCI devices. You can
+ make the kernel exclude IRQs of your ISA cards
+ this way.
+ pirqaddr=0xAAAAA [X86] Specify the physical address
+ of the PIRQ table (normally generated
+ by the BIOS) if it is outside the
+ F0000h-100000h range.
+ lastbus=N [X86] Scan all buses thru bus #N. Can be
+ useful if the kernel is unable to find your
+ secondary buses and you want to tell it
+ explicitly which ones they are.
+ assign-busses [X86] Always assign all PCI bus
+ numbers ourselves, overriding
+ whatever the firmware may have done.
+ usepirqmask [X86] Honor the possible IRQ mask stored
+ in the BIOS $PIR table. This is needed on
+ some systems with broken BIOSes, notably
+ some HP Pavilion N5400 and Omnibook XE3
+ notebooks. This will have no effect if ACPI
+ IRQ routing is enabled.
+ noacpi [X86] Do not use ACPI for IRQ routing
+ or for PCI scanning.
+ use_crs [X86] Use PCI host bridge window information
+ from ACPI. On BIOSes from 2008 or later, this
+ is enabled by default. If you need to use this,
+ please report a bug.
+ nocrs [X86] Ignore PCI host bridge windows from ACPI.
+ If you need to use this, please report a bug.
+ routeirq Do IRQ routing for all PCI devices.
+ This is normally done in pci_enable_device(),
+ so this option is a temporary workaround
+ for broken drivers that don't call it.
+ skip_isa_align [X86] do not align io start addr, so can
+ handle more pci cards
+ noearly [X86] Don't do any early type 1 scanning.
+ This might help on some broken boards which
+ machine check when some devices' config space
+ is read. But various workarounds are disabled
+ and some IOMMU drivers will not work.
+ bfsort Sort PCI devices into breadth-first order.
+ This sorting is done to get a device
+ order compatible with older (<= 2.4) kernels.
+ nobfsort Don't sort PCI devices into breadth-first order.
+ pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
+ tuning and use the BIOS-configured MPS defaults.
+ pcie_bus_safe Set every device's MPS to the largest value
+ supported by all devices below the root complex.
+ pcie_bus_perf Set device MPS to the largest allowable MPS
+ based on its parent bus. Also set MRRS (Max
+ Read Request Size) to the largest supported
+ value (no larger than the MPS that the device
+ or bus can support) for best performance.
+ pcie_bus_peer2peer Set every device's MPS to 128B, which
+ every device is guaranteed to support. This
+ configuration allows peer-to-peer DMA between
+ any pair of devices, possibly at the cost of
+ reduced performance. This also guarantees
+ that hot-added devices will work.
+ cbiosize=nn[KMG] The fixed amount of bus space which is
+ reserved for the CardBus bridge's IO window.
+ The default value is 256 bytes.
+ cbmemsize=nn[KMG] The fixed amount of bus space which is
+ reserved for the CardBus bridge's memory
+ window. The default value is 64 megabytes.
+ resource_alignment=
+ Format:
+ [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
+ [<order of align>@]pci:<vendor>:<device>\
+ [:<subvendor>:<subdevice>][; ...]
+ Specifies alignment and device to reassign
+ aligned memory resources.
+ If <order of align> is not specified,
+ PAGE_SIZE is used as alignment.
+ PCI-PCI bridge can be specified, if resource
+ windows need to be expanded.
+ To specify the alignment for several
+ instances of a device, the PCI vendor,
+ device, subvendor, and subdevice may be
+ specified, e.g., 4096@pci:8086:9c22:103c:198f
+ ecrc= Enable/disable PCIe ECRC (transaction layer
+ end-to-end CRC checking).
+ bios: Use BIOS/firmware settings. This is the
+ the default.
+ off: Turn ECRC off
+ on: Turn ECRC on.
+ hpiosize=nn[KMG] The fixed amount of bus space which is
+ reserved for hotplug bridge's IO window.
+ Default size is 256 bytes.
+ hpmemsize=nn[KMG] The fixed amount of bus space which is
+ reserved for hotplug bridge's memory window.
+ Default size is 2 megabytes.
+ hpbussize=nn The minimum amount of additional bus numbers
+ reserved for buses below a hotplug bridge.
+ Default is 1.
+ realloc= Enable/disable reallocating PCI bridge resources
+ if allocations done by BIOS are too small to
+ accommodate resources required by all child
+ devices.
+ off: Turn realloc off
+ on: Turn realloc on
+ realloc same as realloc=on
+ noari do not use PCIe ARI.
+ pcie_scan_all Scan all possible PCIe devices. Otherwise we
+ only look for one device below a PCIe downstream
+ port.
+
+ pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
+ Management.
+ off Disable ASPM.
+ force Enable ASPM even on devices that claim not to support it.
+ WARNING: Forcing ASPM on may cause system lockups.
+
+ pcie_hp= [PCIE] PCI Express Hotplug driver options:
+ nomsi Do not use MSI for PCI Express Native Hotplug (this
+ makes all PCIe ports use INTx for hotplug services).
+
+ pcie_ports= [PCIE] PCIe ports handling:
+ auto Ask the BIOS whether or not to use native PCIe services
+ associated with PCIe ports (PME, hot-plug, AER). Use
+ them only if that is allowed by the BIOS.
+ native Use native PCIe services associated with PCIe ports
+ unconditionally.
+ compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
+ ports driver.
+
+ pcie_port_pm= [PCIE] PCIe port power management handling:
+ off Disable power management of all PCIe ports
+ force Forcibly enable power management of all PCIe ports
+
+ pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
+ nomsi Do not use MSI for native PCIe PME signaling (this makes
+ all PCIe root ports use INTx for all services).
+
+ pcmv= [HW,PCMCIA] BadgePAD 4
+
+ pd_ignore_unused
+ [PM]
+ Keep all power-domains already enabled by bootloader on,
+ even if no driver has claimed them. This is useful
+ for debug and development, but should not be
+ needed on a platform with proper driver support.
+
+ pd. [PARIDE]
+ See Documentation/blockdev/paride.txt.
+
+ pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
+ boot time.
+ Format: { 0 | 1 }
+ See arch/parisc/kernel/pdc_chassis.c
+
+ percpu_alloc= Select which percpu first chunk allocator to use.
+ Currently supported values are "embed" and "page".
+ Archs may support subset or none of the selections.
+ See comments in mm/percpu.c for details on each
+ allocator. This parameter is primarily for debugging
+ and performance comparison.
+
+ pf. [PARIDE]
+ See Documentation/blockdev/paride.txt.
+
+ pg. [PARIDE]
+ See Documentation/blockdev/paride.txt.
+
+ pirq= [SMP,APIC] Manual mp-table setup
+ See Documentation/x86/i386/IO-APIC.txt.
+
+ plip= [PPT,NET] Parallel port network link
+ Format: { parport<nr> | timid | 0 }
+ See also Documentation/parport.txt.
+
+ pmtmr= [X86] Manual setup of pmtmr I/O Port.
+ Override pmtimer IOPort with a hex value.
+ e.g. pmtmr=0x508
+
+ pnp.debug=1 [PNP]
+ Enable PNP debug messages (depends on the
+ CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
+ via /sys/module/pnp/parameters/debug. We always show
+ current resource usage; turning this on also shows
+ possible settings and some assignment information.
+
+ pnpacpi= [ACPI]
+ { off }
+
+ pnpbios= [ISAPNP]
+ { on | off | curr | res | no-curr | no-res }
+
+ pnp_reserve_irq=
+ [ISAPNP] Exclude IRQs for the autoconfiguration
+
+ pnp_reserve_dma=
+ [ISAPNP] Exclude DMAs for the autoconfiguration
+
+ pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
+ Ranges are in pairs (I/O port base and size).
+
+ pnp_reserve_mem=
+ [ISAPNP] Exclude memory regions for the
+ autoconfiguration.
+ Ranges are in pairs (memory base and size).
+
+ ports= [IP_VS_FTP] IPVS ftp helper module
+ Default is 21.
+ Up to 8 (IP_VS_APP_MAX_PORTS) ports
+ may be specified.
+ Format: <port>,<port>....
+
+ ppc_strict_facility_enable
+ [PPC] This option catches any kernel floating point,
+ Altivec, VSX and SPE outside of regions specifically
+ allowed (eg kernel_enable_fpu()/kernel_disable_fpu()).
+ There is some performance impact when enabling this.
+
+ print-fatal-signals=
+ [KNL] debug: print fatal signals
+
+ If enabled, warn about various signal handling
+ related application anomalies: too many signals,
+ too many POSIX.1 timers, fatal signals causing a
+ coredump - etc.
+
+ If you hit the warning due to signal overflow,
+ you might want to try "ulimit -i unlimited".
+
+ default: off.
+
+ printk.always_kmsg_dump=
+ Trigger kmsg_dump for cases other than kernel oops or
+ panics
+ Format: <bool> (1/Y/y=enable, 0/N/n=disable)
+ default: disabled
+
+ printk.devkmsg={on,off,ratelimit}
+ Control writing to /dev/kmsg.
+ on - unlimited logging to /dev/kmsg from userspace
+ off - logging to /dev/kmsg disabled
+ ratelimit - ratelimit the logging
+ Default: ratelimit
+
+ printk.time= Show timing data prefixed to each printk message line
+ Format: <bool> (1/Y/y=enable, 0/N/n=disable)
+
+ processor.max_cstate= [HW,ACPI]
+ Limit processor to maximum C-state
+ max_cstate=9 overrides any DMI blacklist limit.
+
+ processor.nocst [HW,ACPI]
+ Ignore the _CST method to determine C-states,
+ instead using the legacy FADT method
+
+ profile= [KNL] Enable kernel profiling via /proc/profile
+ Format: [schedule,]<number>
+ Param: "schedule" - profile schedule points.
+ Param: <number> - step/bucket size as a power of 2 for
+ statistical time based profiling.
+ Param: "sleep" - profile D-state sleeping (millisecs).
+ Requires CONFIG_SCHEDSTATS
+ Param: "kvm" - profile VM exits.
+
+ prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
+ before loading.
+ See Documentation/blockdev/ramdisk.txt.
+
+ psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
+ probe for; one of (bare|imps|exps|lifebook|any).
+ psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
+ per second.
+ psmouse.resetafter= [HW,MOUSE]
+ Try to reset the device after so many bad packets
+ (0 = never).
+ psmouse.resolution=
+ [HW,MOUSE] Set desired mouse resolution, in dpi.
+ psmouse.smartscroll=
+ [HW,MOUSE] Controls Logitech smartscroll autorepeat.
+ 0 = disabled, 1 = enabled (default).
+
+ pstore.backend= Specify the name of the pstore backend to use
+
+ pt. [PARIDE]
+ See Documentation/blockdev/paride.txt.
+
+ pty.legacy_count=
+ [KNL] Number of legacy pty's. Overwrites compiled-in
+ default number.
+
+ quiet [KNL] Disable most log messages
+
+ r128= [HW,DRM]
+
+ raid= [HW,RAID]
+ See Documentation/md.txt.
+
+ ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
+ See Documentation/blockdev/ramdisk.txt.
+
+ rcu_nocbs= [KNL]
+ The argument is a cpu list, as described above.
+
+ In kernels built with CONFIG_RCU_NOCB_CPU=y, set
+ the specified list of CPUs to be no-callback CPUs.
+ Invocation of these CPUs' RCU callbacks will
+ be offloaded to "rcuox/N" kthreads created for
+ that purpose, where "x" is "b" for RCU-bh, "p"
+ for RCU-preempt, and "s" for RCU-sched, and "N"
+ is the CPU number. This reduces OS jitter on the
+ offloaded CPUs, which can be useful for HPC and
+ real-time workloads. It can also improve energy
+ efficiency for asymmetric multiprocessors.
+
+ rcu_nocb_poll [KNL]
+ Rather than requiring that offloaded CPUs
+ (specified by rcu_nocbs= above) explicitly
+ awaken the corresponding "rcuoN" kthreads,
+ make these kthreads poll for callbacks.
+ This improves the real-time response for the
+ offloaded CPUs by relieving them of the need to
+ wake up the corresponding kthread, but degrades
+ energy efficiency by requiring that the kthreads
+ periodically wake up to do the polling.
+
+ rcutree.blimit= [KNL]
+ Set maximum number of finished RCU callbacks to
+ process in one batch.
+
+ rcutree.dump_tree= [KNL]
+ Dump the structure of the rcu_node combining tree
+ out at early boot. This is used for diagnostic
+ purposes, to verify correct tree setup.
+
+ rcutree.gp_cleanup_delay= [KNL]
+ Set the number of jiffies to delay each step of
+ RCU grace-period cleanup. This only has effect
+ when CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP is set.
+
+ rcutree.gp_init_delay= [KNL]
+ Set the number of jiffies to delay each step of
+ RCU grace-period initialization. This only has
+ effect when CONFIG_RCU_TORTURE_TEST_SLOW_INIT
+ is set.
+
+ rcutree.gp_preinit_delay= [KNL]
+ Set the number of jiffies to delay each step of
+ RCU grace-period pre-initialization, that is,
+ the propagation of recent CPU-hotplug changes up
+ the rcu_node combining tree. This only has effect
+ when CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT is set.
+
+ rcutree.rcu_fanout_exact= [KNL]
+ Disable autobalancing of the rcu_node combining
+ tree. This is used by rcutorture, and might
+ possibly be useful for architectures having high
+ cache-to-cache transfer latencies.
+
+ rcutree.rcu_fanout_leaf= [KNL]
+ Change the number of CPUs assigned to each
+ leaf rcu_node structure. Useful for very
+ large systems, which will choose the value 64,
+ and for NUMA systems with large remote-access
+ latencies, which will choose a value aligned
+ with the appropriate hardware boundaries.
+
+ rcutree.jiffies_till_sched_qs= [KNL]
+ Set required age in jiffies for a
+ given grace period before RCU starts
+ soliciting quiescent-state help from
+ rcu_note_context_switch().
+
+ rcutree.jiffies_till_first_fqs= [KNL]
+ Set delay from grace-period initialization to
+ first attempt to force quiescent states.
+ Units are jiffies, minimum value is zero,
+ and maximum value is HZ.
+
+ rcutree.jiffies_till_next_fqs= [KNL]
+ Set delay between subsequent attempts to force
+ quiescent states. Units are jiffies, minimum
+ value is one, and maximum value is HZ.
+
+ rcutree.kthread_prio= [KNL,BOOT]
+ Set the SCHED_FIFO priority of the RCU per-CPU
+ kthreads (rcuc/N). This value is also used for
+ the priority of the RCU boost threads (rcub/N)
+ and for the RCU grace-period kthreads (rcu_bh,
+ rcu_preempt, and rcu_sched). If RCU_BOOST is
+ set, valid values are 1-99 and the default is 1
+ (the least-favored priority). Otherwise, when
+ RCU_BOOST is not set, valid values are 0-99 and
+ the default is zero (non-realtime operation).
+
+ rcutree.rcu_nocb_leader_stride= [KNL]
+ Set the number of NOCB kthread groups, which
+ defaults to the square root of the number of
+ CPUs. Larger numbers reduces the wakeup overhead
+ on the per-CPU grace-period kthreads, but increases
+ that same overhead on each group's leader.
+
+ rcutree.qhimark= [KNL]
+ Set threshold of queued RCU callbacks beyond which
+ batch limiting is disabled.
+
+ rcutree.qlowmark= [KNL]
+ Set threshold of queued RCU callbacks below which
+ batch limiting is re-enabled.
+
+ rcutree.rcu_idle_gp_delay= [KNL]
+ Set wakeup interval for idle CPUs that have
+ RCU callbacks (RCU_FAST_NO_HZ=y).
+
+ rcutree.rcu_idle_lazy_gp_delay= [KNL]
+ Set wakeup interval for idle CPUs that have
+ only "lazy" RCU callbacks (RCU_FAST_NO_HZ=y).
+ Lazy RCU callbacks are those which RCU can
+ prove do nothing more than free memory.
+
+ rcuperf.gp_exp= [KNL]
+ Measure performance of expedited synchronous
+ grace-period primitives.
+
+ rcuperf.holdoff= [KNL]
+ Set test-start holdoff period. The purpose of
+ this parameter is to delay the start of the
+ test until boot completes in order to avoid
+ interference.
+
+ rcuperf.nreaders= [KNL]
+ Set number of RCU readers. The value -1 selects
+ N, where N is the number of CPUs. A value
+ "n" less than -1 selects N-n+1, where N is again
+ the number of CPUs. For example, -2 selects N
+ (the number of CPUs), -3 selects N+1, and so on.
+ A value of "n" less than or equal to -N selects
+ a single reader.
+
+ rcuperf.nwriters= [KNL]
+ Set number of RCU writers. The values operate
+ the same as for rcuperf.nreaders.
+ N, where N is the number of CPUs
+
+ rcuperf.perf_runnable= [BOOT]
+ Start rcuperf running at boot time.
+
+ rcuperf.shutdown= [KNL]
+ Shut the system down after performance tests
+ complete. This is useful for hands-off automated
+ testing.
+
+ rcuperf.perf_type= [KNL]
+ Specify the RCU implementation to test.
+
+ rcuperf.verbose= [KNL]
+ Enable additional printk() statements.
+
+ rcutorture.cbflood_inter_holdoff= [KNL]
+ Set holdoff time (jiffies) between successive
+ callback-flood tests.
+
+ rcutorture.cbflood_intra_holdoff= [KNL]
+ Set holdoff time (jiffies) between successive
+ bursts of callbacks within a given callback-flood
+ test.
+
+ rcutorture.cbflood_n_burst= [KNL]
+ Set the number of bursts making up a given
+ callback-flood test. Set this to zero to
+ disable callback-flood testing.
+
+ rcutorture.cbflood_n_per_burst= [KNL]
+ Set the number of callbacks to be registered
+ in a given burst of a callback-flood test.
+
+ rcutorture.fqs_duration= [KNL]
+ Set duration of force_quiescent_state bursts
+ in microseconds.
+
+ rcutorture.fqs_holdoff= [KNL]
+ Set holdoff time within force_quiescent_state bursts
+ in microseconds.
+
+ rcutorture.fqs_stutter= [KNL]
+ Set wait time between force_quiescent_state bursts
+ in seconds.
+
+ rcutorture.gp_cond= [KNL]
+ Use conditional/asynchronous update-side
+ primitives, if available.
+
+ rcutorture.gp_exp= [KNL]
+ Use expedited update-side primitives, if available.
+
+ rcutorture.gp_normal= [KNL]
+ Use normal (non-expedited) asynchronous
+ update-side primitives, if available.
+
+ rcutorture.gp_sync= [KNL]
+ Use normal (non-expedited) synchronous
+ update-side primitives, if available. If all
+ of rcutorture.gp_cond=, rcutorture.gp_exp=,
+ rcutorture.gp_normal=, and rcutorture.gp_sync=
+ are zero, rcutorture acts as if is interpreted
+ they are all non-zero.
+
+ rcutorture.n_barrier_cbs= [KNL]
+ Set callbacks/threads for rcu_barrier() testing.
+
+ rcutorture.nfakewriters= [KNL]
+ Set number of concurrent RCU writers. These just
+ stress RCU, they don't participate in the actual
+ test, hence the "fake".
+
+ rcutorture.nreaders= [KNL]
+ Set number of RCU readers. The value -1 selects
+ N-1, where N is the number of CPUs. A value
+ "n" less than -1 selects N-n-2, where N is again
+ the number of CPUs. For example, -2 selects N
+ (the number of CPUs), -3 selects N+1, and so on.
+
+ rcutorture.object_debug= [KNL]
+ Enable debug-object double-call_rcu() testing.
+
+ rcutorture.onoff_holdoff= [KNL]
+ Set time (s) after boot for CPU-hotplug testing.
+
+ rcutorture.onoff_interval= [KNL]
+ Set time (s) between CPU-hotplug operations, or
+ zero to disable CPU-hotplug testing.
+
+ rcutorture.shuffle_interval= [KNL]
+ Set task-shuffle interval (s). Shuffling tasks
+ allows some CPUs to go into dyntick-idle mode
+ during the rcutorture test.
+
+ rcutorture.shutdown_secs= [KNL]
+ Set time (s) after boot system shutdown. This
+ is useful for hands-off automated testing.
+
+ rcutorture.stall_cpu= [KNL]
+ Duration of CPU stall (s) to test RCU CPU stall
+ warnings, zero to disable.
+
+ rcutorture.stall_cpu_holdoff= [KNL]
+ Time to wait (s) after boot before inducing stall.
+
+ rcutorture.stat_interval= [KNL]
+ Time (s) between statistics printk()s.
+
+ rcutorture.stutter= [KNL]
+ Time (s) to stutter testing, for example, specifying
+ five seconds causes the test to run for five seconds,
+ wait for five seconds, and so on. This tests RCU's
+ ability to transition abruptly to and from idle.
+
+ rcutorture.test_boost= [KNL]
+ Test RCU priority boosting? 0=no, 1=maybe, 2=yes.
+ "Maybe" means test if the RCU implementation
+ under test support RCU priority boosting.
+
+ rcutorture.test_boost_duration= [KNL]
+ Duration (s) of each individual boost test.
+
+ rcutorture.test_boost_interval= [KNL]
+ Interval (s) between each boost test.
+
+ rcutorture.test_no_idle_hz= [KNL]
+ Test RCU's dyntick-idle handling. See also the
+ rcutorture.shuffle_interval parameter.
+
+ rcutorture.torture_runnable= [BOOT]
+ Start rcutorture running at boot time.
+
+ rcutorture.torture_type= [KNL]
+ Specify the RCU implementation to test.
+
+ rcutorture.verbose= [KNL]
+ Enable additional printk() statements.
+
+ rcupdate.rcu_cpu_stall_suppress= [KNL]
+ Suppress RCU CPU stall warning messages.
+
+ rcupdate.rcu_cpu_stall_timeout= [KNL]
+ Set timeout for RCU CPU stall warning messages.
+
+ rcupdate.rcu_expedited= [KNL]
+ Use expedited grace-period primitives, for
+ example, synchronize_rcu_expedited() instead
+ of synchronize_rcu(). This reduces latency,
+ but can increase CPU utilization, degrade
+ real-time latency, and degrade energy efficiency.
+ No effect on CONFIG_TINY_RCU kernels.
+
+ rcupdate.rcu_normal= [KNL]
+ Use only normal grace-period primitives,
+ for example, synchronize_rcu() instead of
+ synchronize_rcu_expedited(). This improves
+ real-time latency, CPU utilization, and
+ energy efficiency, but can expose users to
+ increased grace-period latency. This parameter
+ overrides rcupdate.rcu_expedited. No effect on
+ CONFIG_TINY_RCU kernels.
+
+ rcupdate.rcu_normal_after_boot= [KNL]
+ Once boot has completed (that is, after
+ rcu_end_inkernel_boot() has been invoked), use
+ only normal grace-period primitives. No effect
+ on CONFIG_TINY_RCU kernels.
+
+ rcupdate.rcu_task_stall_timeout= [KNL]
+ Set timeout in jiffies for RCU task stall warning
+ messages. Disable with a value less than or equal
+ to zero.
+
+ rcupdate.rcu_self_test= [KNL]
+ Run the RCU early boot self tests
+
+ rcupdate.rcu_self_test_bh= [KNL]
+ Run the RCU bh early boot self tests
+
+ rcupdate.rcu_self_test_sched= [KNL]
+ Run the RCU sched early boot self tests
+
+ rdinit= [KNL]
+ Format: <full_path>
+ Run specified binary instead of /init from the ramdisk,
+ used for early userspace startup. See initrd.
+
+ reboot= [KNL]
+ Format (x86 or x86_64):
+ [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
+ [[,]s[mp]#### \
+ [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \
+ [[,]f[orce]
+ Where reboot_mode is one of warm (soft) or cold (hard) or gpio,
+ reboot_type is one of bios, acpi, kbd, triple, efi, or pci,
+ reboot_force is either force or not specified,
+ reboot_cpu is s[mp]#### with #### being the processor
+ to be used for rebooting.
+
+ relax_domain_level=
+ [KNL, SMP] Set scheduler's default relax_domain_level.
+ See Documentation/cgroup-v1/cpusets.txt.
+
+ relative_sleep_states=
+ [SUSPEND] Use sleep state labeling where the deepest
+ state available other than hibernation is always "mem".
+ Format: { "0" | "1" }
+ 0 -- Traditional sleep state labels.
+ 1 -- Relative sleep state labels.
+
+ reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
+
+ reservetop= [X86-32]
+ Format: nn[KMG]
+ Reserves a hole at the top of the kernel virtual
+ address space.
+
+ reservelow= [X86]
+ Format: nn[K]
+ Set the amount of memory to reserve for BIOS at
+ the bottom of the address space.
+
+ reset_devices [KNL] Force drivers to reset the underlying device
+ during initialization.
+
+ resume= [SWSUSP]
+ Specify the partition device for software suspend
+ Format:
+ {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
+
+ resume_offset= [SWSUSP]
+ Specify the offset from the beginning of the partition
+ given by "resume=" at which the swap header is located,
+ in <PAGE_SIZE> units (needed only for swap files).
+ See Documentation/power/swsusp-and-swap-files.txt
+
+ resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
+ read the resume files
+
+ resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
+ Useful for devices that are detected asynchronously
+ (e.g. USB and MMC devices).
+
+ hibernate= [HIBERNATION]
+ noresume Don't check if there's a hibernation image
+ present during boot.
+ nocompress Don't compress/decompress hibernation images.
+ no Disable hibernation and resume.
+ protect_image Turn on image protection during restoration
+ (that will set all pages holding image data
+ during restoration read-only).
+
+ retain_initrd [RAM] Keep initrd memory after extraction
+
+ rfkill.default_state=
+ 0 "airplane mode". All wifi, bluetooth, wimax, gps, fm,
+ etc. communication is blocked by default.
+ 1 Unblocked.
+
+ rfkill.master_switch_mode=
+ 0 The "airplane mode" button does nothing.
+ 1 The "airplane mode" button toggles between everything
+ blocked and the previous configuration.
+ 2 The "airplane mode" button toggles between everything
+ blocked and everything unblocked.
+
+ rhash_entries= [KNL,NET]
+ Set number of hash buckets for route cache
+
+ ro [KNL] Mount root device read-only on boot
+
+ rodata= [KNL]
+ on Mark read-only kernel memory as read-only (default).
+ off Leave read-only kernel memory writable for debugging.
+
+ rockchip.usb_uart
+ Enable the uart passthrough on the designated usb port
+ on Rockchip SoCs. When active, the signals of the
+ debug-uart get routed to the D+ and D- pins of the usb
+ port and the regular usb controller gets disabled.
+
+ root= [KNL] Root filesystem
+ See name_to_dev_t comment in init/do_mounts.c.
+
+ rootdelay= [KNL] Delay (in seconds) to pause before attempting to
+ mount the root filesystem
+
+ rootflags= [KNL] Set root filesystem mount option string
+
+ rootfstype= [KNL] Set root filesystem type
+
+ rootwait [KNL] Wait (indefinitely) for root device to show up.
+ Useful for devices that are detected asynchronously
+ (e.g. USB and MMC devices).
+
+ rproc_mem=nn[KMG][@address]
+ [KNL,ARM,CMA] Remoteproc physical memory block.
+ Memory area to be used by remote processor image,
+ managed by CMA.
+
+ rw [KNL] Mount root device read-write on boot
+
+ S [KNL] Run init in single mode
+
+ s390_iommu= [HW,S390]
+ Set s390 IOTLB flushing mode
+ strict
+ With strict flushing every unmap operation will result in
+ an IOTLB flush. Default is lazy flushing before reuse,
+ which is faster.
+
+ sa1100ir [NET]
+ See drivers/net/irda/sa1100_ir.c.
+
+ sbni= [NET] Granch SBNI12 leased line adapter
+
+ sched_debug [KNL] Enables verbose scheduler debug messages.
+
+ schedstats= [KNL,X86] Enable or disable scheduled statistics.
+ Allowed values are enable and disable. This feature
+ incurs a small amount of overhead in the scheduler
+ but is useful for debugging and performance tuning.
+
+ skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
+ xtime_lock contention on larger systems, and/or RCU lock
+ contention on all systems with CONFIG_MAXSMP set.
+ Format: { "0" | "1" }
+ 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
+ 1 -- enable.
+ Note: increases power consumption, thus should only be
+ enabled if running jitter sensitive (HPC/RT) workloads.
+
+ security= [SECURITY] Choose a security module to enable at boot.
+ If this boot parameter is not specified, only the first
+ security module asking for security registration will be
+ loaded. An invalid security module name will be treated
+ as if no module has been chosen.
+
+ selinux= [SELINUX] Disable or enable SELinux at boot time.
+ Format: { "0" | "1" }
+ See security/selinux/Kconfig help text.
+ 0 -- disable.
+ 1 -- enable.
+ Default value is set via kernel config option.
+ If enabled at boot time, /selinux/disable can be used
+ later to disable prior to initial policy load.
+
+ apparmor= [APPARMOR] Disable or enable AppArmor at boot time
+ Format: { "0" | "1" }
+ See security/apparmor/Kconfig help text
+ 0 -- disable.
+ 1 -- enable.
+ Default value is set via kernel config option.
+
+ serialnumber [BUGS=X86-32]
+
+ shapers= [NET]
+ Maximal number of shapers.
+
+ show_msr= [x86] show boot-time MSR settings
+ Format: { <integer> }
+ Show boot-time (BIOS-initialized) MSR settings.
+ The parameter means the number of CPUs to show,
+ for example 1 means boot CPU only.
+
+ simeth= [IA-64]
+ simscsi=
+
+ slram= [HW,MTD]
+
+ slab_nomerge [MM]
+ Disable merging of slabs with similar size. May be
+ necessary if there is some reason to distinguish
+ allocs to different slabs. Debug options disable
+ merging on their own.
+ For more information see Documentation/vm/slub.txt.
+
+ slab_max_order= [MM, SLAB]
+ Determines the maximum allowed order for slabs.
+ A high setting may cause OOMs due to memory
+ fragmentation. Defaults to 1 for systems with
+ more than 32MB of RAM, 0 otherwise.
+
+ slub_debug[=options[,slabs]] [MM, SLUB]
+ Enabling slub_debug allows one to determine the
+ culprit if slab objects become corrupted. Enabling
+ slub_debug can create guard zones around objects and
+ may poison objects when not in use. Also tracks the
+ last alloc / free. For more information see
+ Documentation/vm/slub.txt.
+
+ slub_max_order= [MM, SLUB]
+ Determines the maximum allowed order for slabs.
+ A high setting may cause OOMs due to memory
+ fragmentation. For more information see
+ Documentation/vm/slub.txt.
+
+ slub_min_objects= [MM, SLUB]
+ The minimum number of objects per slab. SLUB will
+ increase the slab order up to slub_max_order to
+ generate a sufficiently large slab able to contain
+ the number of objects indicated. The higher the number
+ of objects the smaller the overhead of tracking slabs
+ and the less frequently locks need to be acquired.
+ For more information see Documentation/vm/slub.txt.
+
+ slub_min_order= [MM, SLUB]
+ Determines the minimum page order for slabs. Must be
+ lower than slub_max_order.
+ For more information see Documentation/vm/slub.txt.
+
+ slub_nomerge [MM, SLUB]
+ Same with slab_nomerge. This is supported for legacy.
+ See slab_nomerge for more information.
+
+ smart2= [HW]
+ Format: <io1>[,<io2>[,...,<io8>]]
+
+ smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
+ smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
+ smsc-ircc2.ircc_sir= [HW] SIR base I/O port
+ smsc-ircc2.ircc_fir= [HW] FIR base I/O port
+ smsc-ircc2.ircc_irq= [HW] IRQ line
+ smsc-ircc2.ircc_dma= [HW] DMA channel
+ smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
+ 0: Toshiba Satellite 1800 (GP data pin select)
+ 1: Fast pin select (default)
+ 2: ATC IRMode
+
+ smt [KNL,S390] Set the maximum number of threads (logical
+ CPUs) to use per physical CPU on systems capable of
+ symmetric multithreading (SMT). Will be capped to the
+ actual hardware limit.
+ Format: <integer>
+ Default: -1 (no limit)
+
+ softlockup_panic=
+ [KNL] Should the soft-lockup detector generate panics.
+ Format: <integer>
+
+ softlockup_all_cpu_backtrace=
+ [KNL] Should the soft-lockup detector generate
+ backtraces on all cpus.
+ Format: <integer>
+
+ sonypi.*= [HW] Sony Programmable I/O Control Device driver
+ See Documentation/laptops/sonypi.txt
+
+ spia_io_base= [HW,MTD]
+ spia_fio_base=
+ spia_pedr=
+ spia_peddr=
+
+ stacktrace [FTRACE]
+ Enabled the stack tracer on boot up.
+
+ stacktrace_filter=[function-list]
+ [FTRACE] Limit the functions that the stack tracer
+ will trace at boot up. function-list is a comma separated
+ list of functions. This list can be changed at run
+ time by the stack_trace_filter file in the debugfs
+ tracing directory. Note, this enables stack tracing
+ and the stacktrace above is not needed.
+
+ sti= [PARISC,HW]
+ Format: <num>
+ Set the STI (builtin display/keyboard on the HP-PARISC
+ machines) console (graphic card) which should be used
+ as the initial boot-console.
+ See also comment in drivers/video/console/sticore.c.
+
+ sti_font= [HW]
+ See comment in drivers/video/console/sticore.c.
+
+ stifb= [HW]
+ Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
+
+ sunrpc.min_resvport=
+ sunrpc.max_resvport=
+ [NFS,SUNRPC]
+ SunRPC servers often require that client requests
+ originate from a privileged port (i.e. a port in the
+ range 0 < portnr < 1024).
+ An administrator who wishes to reserve some of these
+ ports for other uses may adjust the range that the
+ kernel's sunrpc client considers to be privileged
+ using these two parameters to set the minimum and
+ maximum port values.
+
+ sunrpc.svc_rpc_per_connection_limit=
+ [NFS,SUNRPC]
+ Limit the number of requests that the server will
+ process in parallel from a single connection.
+ The default value is 0 (no limit).
+
+ sunrpc.pool_mode=
+ [NFS]
+ Control how the NFS server code allocates CPUs to
+ service thread pools. Depending on how many NICs
+ you have and where their interrupts are bound, this
+ option will affect which CPUs will do NFS serving.
+ Note: this parameter cannot be changed while the
+ NFS server is running.
+
+ auto the server chooses an appropriate mode
+ automatically using heuristics
+ global a single global pool contains all CPUs
+ percpu one pool for each CPU
+ pernode one pool for each NUMA node (equivalent
+ to global on non-NUMA machines)
+
+ sunrpc.tcp_slot_table_entries=
+ sunrpc.udp_slot_table_entries=
+ [NFS,SUNRPC]
+ Sets the upper limit on the number of simultaneous
+ RPC calls that can be sent from the client to a
+ server. Increasing these values may allow you to
+ improve throughput, but will also increase the
+ amount of memory reserved for use by the client.
+
+ suspend.pm_test_delay=
+ [SUSPEND]
+ Sets the number of seconds to remain in a suspend test
+ mode before resuming the system (see
+ /sys/power/pm_test). Only available when CONFIG_PM_DEBUG
+ is set. Default value is 5.
+
+ swapaccount=[0|1]
+ [KNL] Enable accounting of swap in memory resource
+ controller if no parameter or 1 is given or disable
+ it if 0 is given (See Documentation/cgroup-v1/memory.txt)
+
+ swiotlb= [ARM,IA-64,PPC,MIPS,X86]
+ Format: { <int> | force }
+ <int> -- Number of I/O TLB slabs
+ force -- force using of bounce buffers even if they
+ wouldn't be automatically used by the kernel
+
+ switches= [HW,M68k]
+
+ sysfs.deprecated=0|1 [KNL]
+ Enable/disable old style sysfs layout for old udev
+ on older distributions. When this option is enabled
+ very new udev will not work anymore. When this option
+ is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
+ in older udev will not work anymore.
+ Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
+ the kernel configuration.
+
+ sysrq_always_enabled
+ [KNL]
+ Ignore sysrq setting - this boot parameter will
+ neutralize any effect of /proc/sys/kernel/sysrq.
+ Useful for debugging.
+
+ tcpmhash_entries= [KNL,NET]
+ Set the number of tcp_metrics_hash slots.
+ Default value is 8192 or 16384 depending on total
+ ram pages. This is used to specify the TCP metrics
+ cache size. See Documentation/networking/ip-sysctl.txt
+ "tcp_no_metrics_save" section for more details.
+
+ tdfx= [HW,DRM]
+
+ test_suspend= [SUSPEND][,N]
+ Specify "mem" (for Suspend-to-RAM) or "standby" (for
+ standby suspend) or "freeze" (for suspend type freeze)
+ as the system sleep state during system startup with
+ the optional capability to repeat N number of times.
+ The system is woken from this state using a
+ wakeup-capable RTC alarm.
+
+ thash_entries= [KNL,NET]
+ Set number of hash buckets for TCP connection
+
+ thermal.act= [HW,ACPI]
+ -1: disable all active trip points in all thermal zones
+ <degrees C>: override all lowest active trip points
+
+ thermal.crt= [HW,ACPI]
+ -1: disable all critical trip points in all thermal zones
+ <degrees C>: override all critical trip points
+
+ thermal.nocrt= [HW,ACPI]
+ Set to disable actions on ACPI thermal zone
+ critical and hot trip points.
+
+ thermal.off= [HW,ACPI]
+ 1: disable ACPI thermal control
+
+ thermal.psv= [HW,ACPI]
+ -1: disable all passive trip points
+ <degrees C>: override all passive trip points to this
+ value
+
+ thermal.tzp= [HW,ACPI]
+ Specify global default ACPI thermal zone polling rate
+ <deci-seconds>: poll all this frequency
+ 0: no polling (default)
+
+ threadirqs [KNL]
+ Force threading of all interrupt handlers except those
+ marked explicitly IRQF_NO_THREAD.
+
+ tmem [KNL,XEN]
+ Enable the Transcendent memory driver if built-in.
+
+ tmem.cleancache=0|1 [KNL, XEN]
+ Default is on (1). Disable the usage of the cleancache
+ API to send anonymous pages to the hypervisor.
+
+ tmem.frontswap=0|1 [KNL, XEN]
+ Default is on (1). Disable the usage of the frontswap
+ API to send swap pages to the hypervisor. If disabled
+ the selfballooning and selfshrinking are force disabled.
+
+ tmem.selfballooning=0|1 [KNL, XEN]
+ Default is on (1). Disable the driving of swap pages
+ to the hypervisor.
+
+ tmem.selfshrinking=0|1 [KNL, XEN]
+ Default is on (1). Partial swapoff that immediately
+ transfers pages from Xen hypervisor back to the
+ kernel based on different criteria.
+
+ topology= [S390]
+ Format: {off | on}
+ Specify if the kernel should make use of the cpu
+ topology information if the hardware supports this.
+ The scheduler will make use of this information and
+ e.g. base its process migration decisions on it.
+ Default is on.
+
+ topology_updates= [KNL, PPC, NUMA]
+ Format: {off}
+ Specify if the kernel should ignore (off)
+ topology updates sent by the hypervisor to this
+ LPAR.
+
+ tp720= [HW,PS2]
+
+ tpm_suspend_pcr=[HW,TPM]
+ Format: integer pcr id
+ Specify that at suspend time, the tpm driver
+ should extend the specified pcr with zeros,
+ as a workaround for some chips which fail to
+ flush the last written pcr on TPM_SaveState.
+ This will guarantee that all the other pcrs
+ are saved.
+
+ trace_buf_size=nn[KMG]
+ [FTRACE] will set tracing buffer size on each cpu.
+
+ trace_event=[event-list]
+ [FTRACE] Set and start specified trace events in order
+ to facilitate early boot debugging. The event-list is a
+ comma separated list of trace events to enable. See
+ also Documentation/trace/events.txt
+
+ trace_options=[option-list]
+ [FTRACE] Enable or disable tracer options at boot.
+ The option-list is a comma delimited list of options
+ that can be enabled or disabled just as if you were
+ to echo the option name into
+
+ /sys/kernel/debug/tracing/trace_options
+
+ For example, to enable stacktrace option (to dump the
+ stack trace of each event), add to the command line:
+
+ trace_options=stacktrace
+
+ See also Documentation/trace/ftrace.txt "trace options"
+ section.
+
+ tp_printk[FTRACE]
+ Have the tracepoints sent to printk as well as the
+ tracing ring buffer. This is useful for early boot up
+ where the system hangs or reboots and does not give the
+ option for reading the tracing buffer or performing a
+ ftrace_dump_on_oops.
+
+ To turn off having tracepoints sent to printk,
+ echo 0 > /proc/sys/kernel/tracepoint_printk
+ Note, echoing 1 into this file without the
+ tracepoint_printk kernel cmdline option has no effect.
+
+ ** CAUTION **
+
+ Having tracepoints sent to printk() and activating high
+ frequency tracepoints such as irq or sched, can cause
+ the system to live lock.
+
+ traceoff_on_warning
+ [FTRACE] enable this option to disable tracing when a
+ warning is hit. This turns off "tracing_on". Tracing can
+ be enabled again by echoing '1' into the "tracing_on"
+ file located in /sys/kernel/debug/tracing/
+
+ This option is useful, as it disables the trace before
+ the WARNING dump is called, which prevents the trace to
+ be filled with content caused by the warning output.
+
+ This option can also be set at run time via the sysctl
+ option: kernel/traceoff_on_warning
+
+ transparent_hugepage=
+ [KNL]
+ Format: [always|madvise|never]
+ Can be used to control the default behavior of the system
+ with respect to transparent hugepages.
+ See Documentation/vm/transhuge.txt for more details.
+
+ tsc= Disable clocksource stability checks for TSC.
+ Format: <string>
+ [x86] reliable: mark tsc clocksource as reliable, this
+ disables clocksource verification at runtime, as well
+ as the stability checks done at bootup. Used to enable
+ high-resolution timer mode on older hardware, and in
+ virtualized environment.
+ [x86] noirqtime: Do not use TSC to do irq accounting.
+ Used to run time disable IRQ_TIME_ACCOUNTING on any
+ platforms where RDTSC is slow and this accounting
+ can add overhead.
+
+ turbografx.map[2|3]= [HW,JOY]
+ TurboGraFX parallel port interface
+ Format:
+ <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
+ See also Documentation/input/joystick-parport.txt
+
+ udbg-immortal [PPC] When debugging early kernel crashes that
+ happen after console_init() and before a proper
+ console driver takes over, this boot options might
+ help "seeing" what's going on.
+
+ uhash_entries= [KNL,NET]
+ Set number of hash buckets for UDP/UDP-Lite connections
+
+ uhci-hcd.ignore_oc=
+ [USB] Ignore overcurrent events (default N).
+ Some badly-designed motherboards generate lots of
+ bogus events, for ports that aren't wired to
+ anything. Set this parameter to avoid log spamming.
+ Note that genuine overcurrent events won't be
+ reported either.
+
+ unknown_nmi_panic
+ [X86] Cause panic on unknown NMI.
+
+ usbcore.authorized_default=
+ [USB] Default USB device authorization:
+ (default -1 = authorized except for wireless USB,
+ 0 = not authorized, 1 = authorized)
+
+ usbcore.autosuspend=
+ [USB] The autosuspend time delay (in seconds) used
+ for newly-detected USB devices (default 2). This
+ is the time required before an idle device will be
+ autosuspended. Devices for which the delay is set
+ to a negative value won't be autosuspended at all.
+
+ usbcore.usbfs_snoop=
+ [USB] Set to log all usbfs traffic (default 0 = off).
+
+ usbcore.usbfs_snoop_max=
+ [USB] Maximum number of bytes to snoop in each URB
+ (default = 65536).
+
+ usbcore.blinkenlights=
+ [USB] Set to cycle leds on hubs (default 0 = off).
+
+ usbcore.old_scheme_first=
+ [USB] Start with the old device initialization
+ scheme (default 0 = off).
+
+ usbcore.usbfs_memory_mb=
+ [USB] Memory limit (in MB) for buffers allocated by
+ usbfs (default = 16, 0 = max = 2047).
+
+ usbcore.use_both_schemes=
+ [USB] Try the other device initialization scheme
+ if the first one fails (default 1 = enabled).
+
+ usbcore.initial_descriptor_timeout=
+ [USB] Specifies timeout for the initial 64-byte
+ USB_REQ_GET_DESCRIPTOR request in milliseconds
+ (default 5000 = 5.0 seconds).
+
+ usbcore.nousb [USB] Disable the USB subsystem
+
+ usbhid.mousepoll=
+ [USBHID] The interval which mice are to be polled at.
+
+ usb-storage.delay_use=
+ [UMS] The delay in seconds before a new device is
+ scanned for Logical Units (default 1).
+
+ usb-storage.quirks=
+ [UMS] A list of quirks entries to supplement or
+ override the built-in unusual_devs list. List
+ entries are separated by commas. Each entry has
+ the form VID:PID:Flags where VID and PID are Vendor
+ and Product ID values (4-digit hex numbers) and
+ Flags is a set of characters, each corresponding
+ to a common usb-storage quirk flag as follows:
+ a = SANE_SENSE (collect more than 18 bytes
+ of sense data);
+ b = BAD_SENSE (don't collect more than 18
+ bytes of sense data);
+ c = FIX_CAPACITY (decrease the reported
+ device capacity by one sector);
+ d = NO_READ_DISC_INFO (don't use
+ READ_DISC_INFO command);
+ e = NO_READ_CAPACITY_16 (don't use
+ READ_CAPACITY_16 command);
+ f = NO_REPORT_OPCODES (don't use report opcodes
+ command, uas only);
+ g = MAX_SECTORS_240 (don't transfer more than
+ 240 sectors at a time, uas only);
+ h = CAPACITY_HEURISTICS (decrease the
+ reported device capacity by one
+ sector if the number is odd);
+ i = IGNORE_DEVICE (don't bind to this
+ device);
+ j = NO_REPORT_LUNS (don't use report luns
+ command, uas only);
+ l = NOT_LOCKABLE (don't try to lock and
+ unlock ejectable media);
+ m = MAX_SECTORS_64 (don't transfer more
+ than 64 sectors = 32 KB at a time);
+ n = INITIAL_READ10 (force a retry of the
+ initial READ(10) command);
+ o = CAPACITY_OK (accept the capacity
+ reported by the device);
+ p = WRITE_CACHE (the device cache is ON
+ by default);
+ r = IGNORE_RESIDUE (the device reports
+ bogus residue values);
+ s = SINGLE_LUN (the device has only one
+ Logical Unit);
+ t = NO_ATA_1X (don't allow ATA(12) and ATA(16)
+ commands, uas only);
+ u = IGNORE_UAS (don't bind to the uas driver);
+ w = NO_WP_DETECT (don't test whether the
+ medium is write-protected).
+ y = ALWAYS_SYNC (issue a SYNCHRONIZE_CACHE
+ even if the device claims no cache)
+ Example: quirks=0419:aaf5:rl,0421:0433:rc
+
+ user_debug= [KNL,ARM]
+ Format: <int>
+ See arch/arm/Kconfig.debug help text.
+ 1 - undefined instruction events
+ 2 - system calls
+ 4 - invalid data aborts
+ 8 - SIGSEGV faults
+ 16 - SIGBUS faults
+ Example: user_debug=31
+
+ userpte=
+ [X86] Flags controlling user PTE allocations.
+
+ nohigh = do not allocate PTE pages in
+ HIGHMEM regardless of setting
+ of CONFIG_HIGHPTE.
+
+ vdso= [X86,SH]
+ On X86_32, this is an alias for vdso32=. Otherwise:
+
+ vdso=1: enable VDSO (the default)
+ vdso=0: disable VDSO mapping
+
+ vdso32= [X86] Control the 32-bit vDSO
+ vdso32=1: enable 32-bit VDSO
+ vdso32=0 or vdso32=2: disable 32-bit VDSO
+
+ See the help text for CONFIG_COMPAT_VDSO for more
+ details. If CONFIG_COMPAT_VDSO is set, the default is
+ vdso32=0; otherwise, the default is vdso32=1.
+
+ For compatibility with older kernels, vdso32=2 is an
+ alias for vdso32=0.
+
+ Try vdso32=0 if you encounter an error that says:
+ dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
+
+ vector= [IA-64,SMP]
+ vector=percpu: enable percpu vector domain
+
+ video= [FB] Frame buffer configuration
+ See Documentation/fb/modedb.txt.
+
+ video.brightness_switch_enabled= [0,1]
+ If set to 1, on receiving an ACPI notify event
+ generated by hotkey, video driver will adjust brightness
+ level and then send out the event to user space through
+ the allocated input device; If set to 0, video driver
+ will only send out the event without touching backlight
+ brightness level.
+ default: 1
+
+ virtio_mmio.device=
+ [VMMIO] Memory mapped virtio (platform) device.
+
+ <size>@<baseaddr>:<irq>[:<id>]
+ where:
+ <size> := size (can use standard suffixes
+ like K, M and G)
+ <baseaddr> := physical base address
+ <irq> := interrupt number (as passed to
+ request_irq())
+ <id> := (optional) platform device id
+ example:
+ virtio_mmio.device=1K@0x100b0000:48:7
+
+ Can be used multiple times for multiple devices.
+
+ vga= [BOOT,X86-32] Select a particular video mode
+ See Documentation/x86/boot.txt and
+ Documentation/svga.txt.
+ Use vga=ask for menu.
+ This is actually a boot loader parameter; the value is
+ passed to the kernel using a special protocol.
+
+ vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
+ size of <nn>. This can be used to increase the
+ minimum size (128MB on x86). It can also be used to
+ decrease the size and leave more room for directly
+ mapped kernel RAM.
+
+ vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
+ Format: <command>
+
+ vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
+ Format: <command>
+
+ vmpoff= [KNL,S390] Perform z/VM CP command after power off.
+ Format: <command>
+
+ vsyscall= [X86-64]
+ Controls the behavior of vsyscalls (i.e. calls to
+ fixed addresses of 0xffffffffff600x00 from legacy
+ code). Most statically-linked binaries and older
+ versions of glibc use these calls. Because these
+ functions are at fixed addresses, they make nice
+ targets for exploits that can control RIP.
+
+ emulate [default] Vsyscalls turn into traps and are
+ emulated reasonably safely.
+
+ native Vsyscalls are native syscall instructions.
+ This is a little bit faster than trapping
+ and makes a few dynamic recompilers work
+ better than they would in emulation mode.
+ It also makes exploits much easier to write.
+
+ none Vsyscalls don't work at all. This makes
+ them quite hard to use for exploits but
+ might break your system.
+
+ vt.color= [VT] Default text color.
+ Format: 0xYX, X = foreground, Y = background.
+ Default: 0x07 = light gray on black.
+
+ vt.cur_default= [VT] Default cursor shape.
+ Format: 0xCCBBAA, where AA, BB, and CC are the same as
+ the parameters of the <Esc>[?A;B;Cc escape sequence;
+ see VGA-softcursor.txt. Default: 2 = underline.
+
+ vt.default_blu= [VT]
+ Format: <blue0>,<blue1>,<blue2>,...,<blue15>
+ Change the default blue palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ vt.default_grn= [VT]
+ Format: <green0>,<green1>,<green2>,...,<green15>
+ Change the default green palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ vt.default_red= [VT]
+ Format: <red0>,<red1>,<red2>,...,<red15>
+ Change the default red palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ vt.default_utf8=
+ [VT]
+ Format=<0|1>
+ Set system-wide default UTF-8 mode for all tty's.
+ Default is 1, i.e. UTF-8 mode is enabled for all
+ newly opened terminals.
+
+ vt.global_cursor_default=
+ [VT]
+ Format=<-1|0|1>
+ Set system-wide default for whether a cursor
+ is shown on new VTs. Default is -1,
+ i.e. cursors will be created by default unless
+ overridden by individual drivers. 0 will hide
+ cursors, 1 will display them.
+
+ vt.italic= [VT] Default color for italic text; 0-15.
+ Default: 2 = green.
+
+ vt.underline= [VT] Default color for underlined text; 0-15.
+ Default: 3 = cyan.
+
+ watchdog timers [HW,WDT] For information on watchdog timers,
+ see Documentation/watchdog/watchdog-parameters.txt
+ or other driver-specific files in the
+ Documentation/watchdog/ directory.
+
+ workqueue.watchdog_thresh=
+ If CONFIG_WQ_WATCHDOG is configured, workqueue can
+ warn stall conditions and dump internal state to
+ help debugging. 0 disables workqueue stall
+ detection; otherwise, it's the stall threshold
+ duration in seconds. The default value is 30 and
+ it can be updated at runtime by writing to the
+ corresponding sysfs file.
+
+ workqueue.disable_numa
+ By default, all work items queued to unbound
+ workqueues are affine to the NUMA nodes they're
+ issued on, which results in better behavior in
+ general. If NUMA affinity needs to be disabled for
+ whatever reason, this option can be used. Note
+ that this also can be controlled per-workqueue for
+ workqueues visible under /sys/bus/workqueue/.
+
+ workqueue.power_efficient
+ Per-cpu workqueues are generally preferred because
+ they show better performance thanks to cache
+ locality; unfortunately, per-cpu workqueues tend to
+ be more power hungry than unbound workqueues.
+
+ Enabling this makes the per-cpu workqueues which
+ were observed to contribute significantly to power
+ consumption unbound, leading to measurably lower
+ power usage at the cost of small performance
+ overhead.
+
+ The default value of this parameter is determined by
+ the config option CONFIG_WQ_POWER_EFFICIENT_DEFAULT.
+
+ workqueue.debug_force_rr_cpu
+ Workqueue used to implicitly guarantee that work
+ items queued without explicit CPU specified are put
+ on the local CPU. This guarantee is no longer true
+ and while local CPU is still preferred work items
+ may be put on foreign CPUs. This debug option
+ forces round-robin CPU selection to flush out
+ usages which depend on the now broken guarantee.
+ When enabled, memory and cache locality will be
+ impacted.
+
+ x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
+ default x2apic cluster mode on platforms
+ supporting x2apic.
+
+ x86_intel_mid_timer= [X86-32,APBT]
+ Choose timer option for x86 Intel MID platform.
+ Two valid options are apbt timer only and lapic timer
+ plus one apbt timer for broadcast timer.
+ x86_intel_mid_timer=apbt_only | lapic_and_apbt
+
+ xen_512gb_limit [KNL,X86-64,XEN]
+ Restricts the kernel running paravirtualized under Xen
+ to use only up to 512 GB of RAM. The reason to do so is
+ crash analysis tools and Xen tools for doing domain
+ save/restore/migration must be enabled to handle larger
+ domains.
+
+ xen_emul_unplug= [HW,X86,XEN]
+ Unplug Xen emulated devices
+ Format: [unplug0,][unplug1]
+ ide-disks -- unplug primary master IDE devices
+ aux-ide-disks -- unplug non-primary-master IDE devices
+ nics -- unplug network devices
+ all -- unplug all emulated devices (NICs and IDE disks)
+ unnecessary -- unplugging emulated devices is
+ unnecessary even if the host did not respond to
+ the unplug protocol
+ never -- do not unplug even if version check succeeds
+
+ xen_nopvspin [X86,XEN]
+ Disables the ticketlock slowpath using Xen PV
+ optimizations.
+
+ xen_nopv [X86]
+ Disables the PV optimizations forcing the HVM guest to
+ run as generic HVM guest with no PV drivers.
+
+ xirc2ps_cs= [NET,PCMCIA]
+ Format:
+ <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
+
+------------------------
+
+Todo
+----
+
+ Add more DRM drivers.
--- /dev/null
+RAID arrays
+===========
+
+Boot time assembly of RAID arrays
+---------------------------------
+
+Tools that manage md devices can be found at
+ http://www.kernel.org/pub/linux/utils/raid/
+
+
+You can boot with your md device with the following kernel command
+lines:
+
+for old raid arrays without persistent superblocks::
+
+ md=<md device no.>,<raid level>,<chunk size factor>,<fault level>,dev0,dev1,...,devn
+
+for raid arrays with persistent superblocks::
+
+ md=<md device no.>,dev0,dev1,...,devn
+
+or, to assemble a partitionable array::
+
+ md=d<md device no.>,dev0,dev1,...,devn
+
+``md device no.``
++++++++++++++++++
+
+The number of the md device
+
+================= =========
+``md device no.`` device
+================= =========
+ 0 md0
+ 1 md1
+ 2 md2
+ 3 md3
+ 4 md4
+================= =========
+
+``raid level``
+++++++++++++++
+
+level of the RAID array
+
+=============== =============
+``raid level`` level
+=============== =============
+-1 linear mode
+0 striped mode
+=============== =============
+
+other modes are only supported with persistent super blocks
+
+``chunk size factor``
++++++++++++++++++++++
+
+(raid-0 and raid-1 only)
+
+Set the chunk size as 4k << n.
+
+``fault level``
++++++++++++++++
+
+Totally ignored
+
+``dev0`` to ``devn``
+++++++++++++++++++++
+
+e.g. ``/dev/hda1``, ``/dev/hdc1``, ``/dev/sda1``, ``/dev/sdb1``
+
+A possible loadlin line (Harald Hoyer <HarryH@Royal.Net>) looks like this::
+
+ e:\loadlin\loadlin e:\zimage root=/dev/md0 md=0,0,4,0,/dev/hdb2,/dev/hdc3 ro
+
+
+Boot time autodetection of RAID arrays
+--------------------------------------
+
+When md is compiled into the kernel (not as module), partitions of
+type 0xfd are scanned and automatically assembled into RAID arrays.
+This autodetection may be suppressed with the kernel parameter
+``raid=noautodetect``. As of kernel 2.6.9, only drives with a type 0
+superblock can be autodetected and run at boot time.
+
+The kernel parameter ``raid=partitionable`` (or ``raid=part``) means
+that all auto-detected arrays are assembled as partitionable.
+
+Boot time assembly of degraded/dirty arrays
+-------------------------------------------
+
+If a raid5 or raid6 array is both dirty and degraded, it could have
+undetectable data corruption. This is because the fact that it is
+``dirty`` means that the parity cannot be trusted, and the fact that it
+is degraded means that some datablocks are missing and cannot reliably
+be reconstructed (due to no parity).
+
+For this reason, md will normally refuse to start such an array. This
+requires the sysadmin to take action to explicitly start the array
+despite possible corruption. This is normally done with::
+
+ mdadm --assemble --force ....
+
+This option is not really available if the array has the root
+filesystem on it. In order to support this booting from such an
+array, md supports a module parameter ``start_dirty_degraded`` which,
+when set to 1, bypassed the checks and will allows dirty degraded
+arrays to be started.
+
+So, to boot with a root filesystem of a dirty degraded raid 5 or 6, use::
+
+ md-mod.start_dirty_degraded=1
+
+
+Superblock formats
+------------------
+
+The md driver can support a variety of different superblock formats.
+Currently, it supports superblock formats ``0.90.0`` and the ``md-1`` format
+introduced in the 2.5 development series.
+
+The kernel will autodetect which format superblock is being used.
+
+Superblock format ``0`` is treated differently to others for legacy
+reasons - it is the original superblock format.
+
+
+General Rules - apply for all superblock formats
+------------------------------------------------
+
+An array is ``created`` by writing appropriate superblocks to all
+devices.
+
+It is ``assembled`` by associating each of these devices with an
+particular md virtual device. Once it is completely assembled, it can
+be accessed.
+
+An array should be created by a user-space tool. This will write
+superblocks to all devices. It will usually mark the array as
+``unclean``, or with some devices missing so that the kernel md driver
+can create appropriate redundancy (copying in raid 1, parity
+calculation in raid 4/5).
+
+When an array is assembled, it is first initialized with the
+SET_ARRAY_INFO ioctl. This contains, in particular, a major and minor
+version number. The major version number selects which superblock
+format is to be used. The minor number might be used to tune handling
+of the format, such as suggesting where on each device to look for the
+superblock.
+
+Then each device is added using the ADD_NEW_DISK ioctl. This
+provides, in particular, a major and minor number identifying the
+device to add.
+
+The array is started with the RUN_ARRAY ioctl.
+
+Once started, new devices can be added. They should have an
+appropriate superblock written to them, and then be passed in with
+ADD_NEW_DISK.
+
+Devices that have failed or are not yet active can be detached from an
+array using HOT_REMOVE_DISK.
+
+
+Specific Rules that apply to format-0 super block arrays, and arrays with no superblock (non-persistent)
+--------------------------------------------------------------------------------------------------------
+
+An array can be ``created`` by describing the array (level, chunksize
+etc) in a SET_ARRAY_INFO ioctl. This must have ``major_version==0`` and
+``raid_disks != 0``.
+
+Then uninitialized devices can be added with ADD_NEW_DISK. The
+structure passed to ADD_NEW_DISK must specify the state of the device
+and its role in the array.
+
+Once started with RUN_ARRAY, uninitialized spares can be added with
+HOT_ADD_DISK.
+
+
+MD devices in sysfs
+-------------------
+
+md devices appear in sysfs (``/sys``) as regular block devices,
+e.g.::
+
+ /sys/block/md0
+
+Each ``md`` device will contain a subdirectory called ``md`` which
+contains further md-specific information about the device.
+
+All md devices contain:
+
+ level
+ a text file indicating the ``raid level``. e.g. raid0, raid1,
+ raid5, linear, multipath, faulty.
+ If no raid level has been set yet (array is still being
+ assembled), the value will reflect whatever has been written
+ to it, which may be a name like the above, or may be a number
+ such as ``0``, ``5``, etc.
+
+ raid_disks
+ a text file with a simple number indicating the number of devices
+ in a fully functional array. If this is not yet known, the file
+ will be empty. If an array is being resized this will contain
+ the new number of devices.
+ Some raid levels allow this value to be set while the array is
+ active. This will reconfigure the array. Otherwise it can only
+ be set while assembling an array.
+ A change to this attribute will not be permitted if it would
+ reduce the size of the array. To reduce the number of drives
+ in an e.g. raid5, the array size must first be reduced by
+ setting the ``array_size`` attribute.
+
+ chunk_size
+ This is the size in bytes for ``chunks`` and is only relevant to
+ raid levels that involve striping (0,4,5,6,10). The address space
+ of the array is conceptually divided into chunks and consecutive
+ chunks are striped onto neighbouring devices.
+ The size should be at least PAGE_SIZE (4k) and should be a power
+ of 2. This can only be set while assembling an array
+
+ layout
+ The ``layout`` for the array for the particular level. This is
+ simply a number that is interpretted differently by different
+ levels. It can be written while assembling an array.
+
+ array_size
+ This can be used to artificially constrain the available space in
+ the array to be less than is actually available on the combined
+ devices. Writing a number (in Kilobytes) which is less than
+ the available size will set the size. Any reconfiguration of the
+ array (e.g. adding devices) will not cause the size to change.
+ Writing the word ``default`` will cause the effective size of the
+ array to be whatever size is actually available based on
+ ``level``, ``chunk_size`` and ``component_size``.
+
+ This can be used to reduce the size of the array before reducing
+ the number of devices in a raid4/5/6, or to support external
+ metadata formats which mandate such clipping.
+
+ reshape_position
+ This is either ``none`` or a sector number within the devices of
+ the array where ``reshape`` is up to. If this is set, the three
+ attributes mentioned above (raid_disks, chunk_size, layout) can
+ potentially have 2 values, an old and a new value. If these
+ values differ, reading the attribute returns::
+
+ new (old)
+
+ and writing will effect the ``new`` value, leaving the ``old``
+ unchanged.
+
+ component_size
+ For arrays with data redundancy (i.e. not raid0, linear, faulty,
+ multipath), all components must be the same size - or at least
+ there must a size that they all provide space for. This is a key
+ part or the geometry of the array. It is measured in sectors
+ and can be read from here. Writing to this value may resize
+ the array if the personality supports it (raid1, raid5, raid6),
+ and if the component drives are large enough.
+
+ metadata_version
+ This indicates the format that is being used to record metadata
+ about the array. It can be 0.90 (traditional format), 1.0, 1.1,
+ 1.2 (newer format in varying locations) or ``none`` indicating that
+ the kernel isn't managing metadata at all.
+ Alternately it can be ``external:`` followed by a string which
+ is set by user-space. This indicates that metadata is managed
+ by a user-space program. Any device failure or other event that
+ requires a metadata update will cause array activity to be
+ suspended until the event is acknowledged.
+
+ resync_start
+ The point at which resync should start. If no resync is needed,
+ this will be a very large number (or ``none`` since 2.6.30-rc1). At
+ array creation it will default to 0, though starting the array as
+ ``clean`` will set it much larger.
+
+ new_dev
+ This file can be written but not read. The value written should
+ be a block device number as major:minor. e.g. 8:0
+ This will cause that device to be attached to the array, if it is
+ available. It will then appear at md/dev-XXX (depending on the
+ name of the device) and further configuration is then possible.
+
+ safe_mode_delay
+ When an md array has seen no write requests for a certain period
+ of time, it will be marked as ``clean``. When another write
+ request arrives, the array is marked as ``dirty`` before the write
+ commences. This is known as ``safe_mode``.
+ The ``certain period`` is controlled by this file which stores the
+ period as a number of seconds. The default is 200msec (0.200).
+ Writing a value of 0 disables safemode.
+
+ array_state
+ This file contains a single word which describes the current
+ state of the array. In many cases, the state can be set by
+ writing the word for the desired state, however some states
+ cannot be explicitly set, and some transitions are not allowed.
+
+ Select/poll works on this file. All changes except between
+ Active_idle and active (which can be frequent and are not
+ very interesting) are notified. active->active_idle is
+ reported if the metadata is externally managed.
+
+ clear
+ No devices, no size, no level
+
+ Writing is equivalent to STOP_ARRAY ioctl
+
+ inactive
+ May have some settings, but array is not active
+ all IO results in error
+
+ When written, doesn't tear down array, but just stops it
+
+ suspended (not supported yet)
+ All IO requests will block. The array can be reconfigured.
+
+ Writing this, if accepted, will block until array is quiessent
+
+ readonly
+ no resync can happen. no superblocks get written.
+
+ Write requests fail
+
+ read-auto
+ like readonly, but behaves like ``clean`` on a write request.
+
+ clean
+ no pending writes, but otherwise active.
+
+ When written to inactive array, starts without resync
+
+ If a write request arrives then
+ if metadata is known, mark ``dirty`` and switch to ``active``.
+ if not known, block and switch to write-pending
+
+ If written to an active array that has pending writes, then fails.
+ active
+ fully active: IO and resync can be happening.
+ When written to inactive array, starts with resync
+
+ write-pending
+ clean, but writes are blocked waiting for ``active`` to be written.
+
+ active-idle
+ like active, but no writes have been seen for a while (safe_mode_delay).
+
+ bitmap/location
+ This indicates where the write-intent bitmap for the array is
+ stored.
+
+ It can be one of ``none``, ``file`` or ``[+-]N``.
+ ``file`` may later be extended to ``file:/file/name``
+ ``[+-]N`` means that many sectors from the start of the metadata.
+
+ This is replicated on all devices. For arrays with externally
+ managed metadata, the offset is from the beginning of the
+ device.
+
+ bitmap/chunksize
+ The size, in bytes, of the chunk which will be represented by a
+ single bit. For RAID456, it is a portion of an individual
+ device. For RAID10, it is a portion of the array. For RAID1, it
+ is both (they come to the same thing).
+
+ bitmap/time_base
+ The time, in seconds, between looking for bits in the bitmap to
+ be cleared. In the current implementation, a bit will be cleared
+ between 2 and 3 times ``time_base`` after all the covered blocks
+ are known to be in-sync.
+
+ bitmap/backlog
+ When write-mostly devices are active in a RAID1, write requests
+ to those devices proceed in the background - the filesystem (or
+ other user of the device) does not have to wait for them.
+ ``backlog`` sets a limit on the number of concurrent background
+ writes. If there are more than this, new writes will by
+ synchronous.
+
+ bitmap/metadata
+ This can be either ``internal`` or ``external``.
+
+ ``internal``
+ is the default and means the metadata for the bitmap
+ is stored in the first 256 bytes of the allocated space and is
+ managed by the md module.
+
+ ``external``
+ means that bitmap metadata is managed externally to
+ the kernel (i.e. by some userspace program)
+
+ bitmap/can_clear
+ This is either ``true`` or ``false``. If ``true``, then bits in the
+ bitmap will be cleared when the corresponding blocks are thought
+ to be in-sync. If ``false``, bits will never be cleared.
+ This is automatically set to ``false`` if a write happens on a
+ degraded array, or if the array becomes degraded during a write.
+ When metadata is managed externally, it should be set to true
+ once the array becomes non-degraded, and this fact has been
+ recorded in the metadata.
+
+
+
+
+As component devices are added to an md array, they appear in the ``md``
+directory as new directories named::
+
+ dev-XXX
+
+where ``XXX`` is a name that the kernel knows for the device, e.g. hdb1.
+Each directory contains:
+
+ block
+ a symlink to the block device in /sys/block, e.g.::
+
+ /sys/block/md0/md/dev-hdb1/block -> ../../../../block/hdb/hdb1
+
+ super
+ A file containing an image of the superblock read from, or
+ written to, that device.
+
+ state
+ A file recording the current state of the device in the array
+ which can be a comma separated list of:
+
+ faulty
+ device has been kicked from active use due to
+ a detected fault, or it has unacknowledged bad
+ blocks
+
+ in_sync
+ device is a fully in-sync member of the array
+
+ writemostly
+ device will only be subject to read
+ requests if there are no other options.
+
+ This applies only to raid1 arrays.
+
+ blocked
+ device has failed, and the failure hasn't been
+ acknowledged yet by the metadata handler.
+
+ Writes that would write to this device if
+ it were not faulty are blocked.
+
+ spare
+ device is working, but not a full member.
+
+ This includes spares that are in the process
+ of being recovered to
+
+ write_error
+ device has ever seen a write error.
+
+ want_replacement
+ device is (mostly) working but probably
+ should be replaced, either due to errors or
+ due to user request.
+
+ replacement
+ device is a replacement for another active
+ device with same raid_disk.
+
+
+ This list may grow in future.
+
+ This can be written to.
+
+ Writing ``faulty`` simulates a failure on the device.
+
+ Writing ``remove`` removes the device from the array.
+
+ Writing ``writemostly`` sets the writemostly flag.
+
+ Writing ``-writemostly`` clears the writemostly flag.
+
+ Writing ``blocked`` sets the ``blocked`` flag.
+
+ Writing ``-blocked`` clears the ``blocked`` flags and allows writes
+ to complete and possibly simulates an error.
+
+ Writing ``in_sync`` sets the in_sync flag.
+
+ Writing ``write_error`` sets writeerrorseen flag.
+
+ Writing ``-write_error`` clears writeerrorseen flag.
+
+ Writing ``want_replacement`` is allowed at any time except to a
+ replacement device or a spare. It sets the flag.
+
+ Writing ``-want_replacement`` is allowed at any time. It clears
+ the flag.
+
+ Writing ``replacement`` or ``-replacement`` is only allowed before
+ starting the array. It sets or clears the flag.
+
+
+ This file responds to select/poll. Any change to ``faulty``
+ or ``blocked`` causes an event.
+
+ errors
+ An approximate count of read errors that have been detected on
+ this device but have not caused the device to be evicted from
+ the array (either because they were corrected or because they
+ happened while the array was read-only). When using version-1
+ metadata, this value persists across restarts of the array.
+
+ This value can be written while assembling an array thus
+ providing an ongoing count for arrays with metadata managed by
+ userspace.
+
+ slot
+ This gives the role that the device has in the array. It will
+ either be ``none`` if the device is not active in the array
+ (i.e. is a spare or has failed) or an integer less than the
+ ``raid_disks`` number for the array indicating which position
+ it currently fills. This can only be set while assembling an
+ array. A device for which this is set is assumed to be working.
+
+ offset
+ This gives the location in the device (in sectors from the
+ start) where data from the array will be stored. Any part of
+ the device before this offset is not touched, unless it is
+ used for storing metadata (Formats 1.1 and 1.2).
+
+ size
+ The amount of the device, after the offset, that can be used
+ for storage of data. This will normally be the same as the
+ component_size. This can be written while assembling an
+ array. If a value less than the current component_size is
+ written, it will be rejected.
+
+ recovery_start
+ When the device is not ``in_sync``, this records the number of
+ sectors from the start of the device which are known to be
+ correct. This is normally zero, but during a recovery
+ operation it will steadily increase, and if the recovery is
+ interrupted, restoring this value can cause recovery to
+ avoid repeating the earlier blocks. With v1.x metadata, this
+ value is saved and restored automatically.
+
+ This can be set whenever the device is not an active member of
+ the array, either before the array is activated, or before
+ the ``slot`` is set.
+
+ Setting this to ``none`` is equivalent to setting ``in_sync``.
+ Setting to any other value also clears the ``in_sync`` flag.
+
+ bad_blocks
+ This gives the list of all known bad blocks in the form of
+ start address and length (in sectors respectively). If output
+ is too big to fit in a page, it will be truncated. Writing
+ ``sector length`` to this file adds new acknowledged (i.e.
+ recorded to disk safely) bad blocks.
+
+ unacknowledged_bad_blocks
+ This gives the list of known-but-not-yet-saved-to-disk bad
+ blocks in the same form of ``bad_blocks``. If output is too big
+ to fit in a page, it will be truncated. Writing to this file
+ adds bad blocks without acknowledging them. This is largely
+ for testing.
+
+
+
+An active md device will also contain an entry for each active device
+in the array. These are named::
+
+ rdNN
+
+where ``NN`` is the position in the array, starting from 0.
+So for a 3 drive array there will be rd0, rd1, rd2.
+These are symbolic links to the appropriate ``dev-XXX`` entry.
+Thus, for example::
+
+ cat /sys/block/md*/md/rd*/state
+
+will show ``in_sync`` on every line.
+
+
+
+Active md devices for levels that support data redundancy (1,4,5,6,10)
+also have
+
+ sync_action
+ a text file that can be used to monitor and control the rebuild
+ process. It contains one word which can be one of:
+
+ resync
+ redundancy is being recalculated after unclean
+ shutdown or creation
+
+ recover
+ a hot spare is being built to replace a
+ failed/missing device
+
+ idle
+ nothing is happening
+ check
+ A full check of redundancy was requested and is
+ happening. This reads all blocks and checks
+ them. A repair may also happen for some raid
+ levels.
+
+ repair
+ A full check and repair is happening. This is
+ similar to ``resync``, but was requested by the
+ user, and the write-intent bitmap is NOT used to
+ optimise the process.
+
+ This file is writable, and each of the strings that could be
+ read are meaningful for writing.
+
+ ``idle`` will stop an active resync/recovery etc. There is no
+ guarantee that another resync/recovery may not be automatically
+ started again, though some event will be needed to trigger
+ this.
+
+ ``resync`` or ``recovery`` can be used to restart the
+ corresponding operation if it was stopped with ``idle``.
+
+ ``check`` and ``repair`` will start the appropriate process
+ providing the current state is ``idle``.
+
+ This file responds to select/poll. Any important change in the value
+ triggers a poll event. Sometimes the value will briefly be
+ ``recover`` if a recovery seems to be needed, but cannot be
+ achieved. In that case, the transition to ``recover`` isn't
+ notified, but the transition away is.
+
+ degraded
+ This contains a count of the number of devices by which the
+ arrays is degraded. So an optimal array will show ``0``. A
+ single failed/missing drive will show ``1``, etc.
+
+ This file responds to select/poll, any increase or decrease
+ in the count of missing devices will trigger an event.
+
+ mismatch_count
+ When performing ``check`` and ``repair``, and possibly when
+ performing ``resync``, md will count the number of errors that are
+ found. The count in ``mismatch_cnt`` is the number of sectors
+ that were re-written, or (for ``check``) would have been
+ re-written. As most raid levels work in units of pages rather
+ than sectors, this may be larger than the number of actual errors
+ by a factor of the number of sectors in a page.
+
+ bitmap_set_bits
+ If the array has a write-intent bitmap, then writing to this
+ attribute can set bits in the bitmap, indicating that a resync
+ would need to check the corresponding blocks. Either individual
+ numbers or start-end pairs can be written. Multiple numbers
+ can be separated by a space.
+
+ Note that the numbers are ``bit`` numbers, not ``block`` numbers.
+ They should be scaled by the bitmap_chunksize.
+
+ sync_speed_min, sync_speed_max
+ This are similar to ``/proc/sys/dev/raid/speed_limit_{min,max}``
+ however they only apply to the particular array.
+
+ If no value has been written to these, or if the word ``system``
+ is written, then the system-wide value is used. If a value,
+ in kibibytes-per-second is written, then it is used.
+
+ When the files are read, they show the currently active value
+ followed by ``(local)`` or ``(system)`` depending on whether it is
+ a locally set or system-wide value.
+
+ sync_completed
+ This shows the number of sectors that have been completed of
+ whatever the current sync_action is, followed by the number of
+ sectors in total that could need to be processed. The two
+ numbers are separated by a ``/`` thus effectively showing one
+ value, a fraction of the process that is complete.
+
+ A ``select`` on this attribute will return when resync completes,
+ when it reaches the current sync_max (below) and possibly at
+ other times.
+
+ sync_speed
+ This shows the current actual speed, in K/sec, of the current
+ sync_action. It is averaged over the last 30 seconds.
+
+ suspend_lo, suspend_hi
+ The two values, given as numbers of sectors, indicate a range
+ within the array where IO will be blocked. This is currently
+ only supported for raid4/5/6.
+
+ sync_min, sync_max
+ The two values, given as numbers of sectors, indicate a range
+ within the array where ``check``/``repair`` will operate. Must be
+ a multiple of chunk_size. When it reaches ``sync_max`` it will
+ pause, rather than complete.
+ You can use ``select`` or ``poll`` on ``sync_completed`` to wait for
+ that number to reach sync_max. Then you can either increase
+ ``sync_max``, or can write ``idle`` to ``sync_action``.
+
+ The value of ``max`` for ``sync_max`` effectively disables the limit.
+ When a resync is active, the value can only ever be increased,
+ never decreased.
+ The value of ``0`` is the minimum for ``sync_min``.
+
+
+
+Each active md device may also have attributes specific to the
+personality module that manages it.
+These are specific to the implementation of the module and could
+change substantially if the implementation changes.
+
+These currently include:
+
+ stripe_cache_size (currently raid5 only)
+ number of entries in the stripe cache. This is writable, but
+ there are upper and lower limits (32768, 17). Default is 256.
+
+ strip_cache_active (currently raid5 only)
+ number of active entries in the stripe cache
+
+ preread_bypass_threshold (currently raid5 only)
+ number of times a stripe requiring preread will be bypassed by
+ a stripe that does not require preread. For fairness defaults
+ to 1. Setting this to 0 disables bypass accounting and
+ requires preread stripes to wait until all full-width stripe-
+ writes are complete. Valid values are 0 to stripe_cache_size.
--- /dev/null
+Mono(tm) Binary Kernel Support for Linux
+-----------------------------------------
+
+To configure Linux to automatically execute Mono-based .NET binaries
+(in the form of .exe files) without the need to use the mono CLR
+wrapper, you can use the BINFMT_MISC kernel support.
+
+This will allow you to execute Mono-based .NET binaries just like any
+other program after you have done the following:
+
+1) You MUST FIRST install the Mono CLR support, either by downloading
+ a binary package, a source tarball or by installing from CVS. Binary
+ packages for several distributions can be found at:
+
+ http://go-mono.com/download.html
+
+ Instructions for compiling Mono can be found at:
+
+ http://www.go-mono.com/compiling.html
+
+ Once the Mono CLR support has been installed, just check that
+ ``/usr/bin/mono`` (which could be located elsewhere, for example
+ ``/usr/local/bin/mono``) is working.
+
+2) You have to compile BINFMT_MISC either as a module or into
+ the kernel (``CONFIG_BINFMT_MISC``) and set it up properly.
+ If you choose to compile it as a module, you will have
+ to insert it manually with modprobe/insmod, as kmod
+ cannot be easily supported with binfmt_misc.
+ Read the file ``binfmt_misc.txt`` in this directory to know
+ more about the configuration process.
+
+3) Add the following entries to ``/etc/rc.local`` or similar script
+ to be run at system startup::
+
+ # Insert BINFMT_MISC module into the kernel
+ if [ ! -e /proc/sys/fs/binfmt_misc/register ]; then
+ /sbin/modprobe binfmt_misc
+ # Some distributions, like Fedora Core, perform
+ # the following command automatically when the
+ # binfmt_misc module is loaded into the kernel
+ # or during normal boot up (systemd-based systems).
+ # Thus, it is possible that the following line
+ # is not needed at all.
+ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
+ fi
+
+ # Register support for .NET CLR binaries
+ if [ -e /proc/sys/fs/binfmt_misc/register ]; then
+ # Replace /usr/bin/mono with the correct pathname to
+ # the Mono CLR runtime (usually /usr/local/bin/mono
+ # when compiling from sources or CVS).
+ echo ':CLR:M::MZ::/usr/bin/mono:' > /proc/sys/fs/binfmt_misc/register
+ else
+ echo "No binfmt_misc support"
+ exit 1
+ fi
+
+4) Check that ``.exe`` binaries can be ran without the need of a
+ wrapper script, simply by launching the ``.exe`` file directly
+ from a command prompt, for example::
+
+ /usr/bin/xsd.exe
+
+ .. note::
+
+ If this fails with a permission denied error, check
+ that the ``.exe`` file has execute permissions.
--- /dev/null
+OOPS tracing
+============
+
+.. note::
+
+ ``ksymoops`` is useless on 2.6 or upper. Please use the Oops in its original
+ format (from ``dmesg``, etc). Ignore any references in this or other docs to
+ "decoding the Oops" or "running it through ksymoops".
+ If you post an Oops from 2.6+ that has been run through ``ksymoops``,
+ people will just tell you to repost it.
+
+Quick Summary
+-------------
+
+Find the Oops and send it to the maintainer of the kernel area that seems to be
+involved with the problem. Don't worry too much about getting the wrong person.
+If you are unsure send it to the person responsible for the code relevant to
+what you were doing. If it occurs repeatably try and describe how to recreate
+it. That's worth even more than the oops.
+
+If you are totally stumped as to whom to send the report, send it to
+linux-kernel@vger.kernel.org. Thanks for your help in making Linux as
+stable as humanly possible.
+
+Where is the Oops?
+----------------------
+
+Normally the Oops text is read from the kernel buffers by klogd and
+handed to ``syslogd`` which writes it to a syslog file, typically
+``/var/log/messages`` (depends on ``/etc/syslog.conf``). Sometimes ``klogd``
+dies, in which case you can run ``dmesg > file`` to read the data from the
+kernel buffers and save it. Or you can ``cat /proc/kmsg > file``, however you
+have to break in to stop the transfer, ``kmsg`` is a "never ending file".
+If the machine has crashed so badly that you cannot enter commands or
+the disk is not available then you have three options :
+
+(1) Hand copy the text from the screen and type it in after the machine
+ has restarted. Messy but it is the only option if you have not
+ planned for a crash. Alternatively, you can take a picture of
+ the screen with a digital camera - not nice, but better than
+ nothing. If the messages scroll off the top of the console, you
+ may find that booting with a higher resolution (eg, ``vga=791``)
+ will allow you to read more of the text. (Caveat: This needs ``vesafb``,
+ so won't help for 'early' oopses)
+
+(2) Boot with a serial console (see
+ :ref:`Documentation/serial-console.txt <serial_console>`),
+ run a null modem to a second machine and capture the output there
+ using your favourite communication program. Minicom works well.
+
+(3) Use Kdump (see Documentation/kdump/kdump.txt),
+ extract the kernel ring buffer from old memory with using dmesg
+ gdbmacro in Documentation/kdump/gdbmacros.txt.
+
+
+Full Information
+----------------
+
+.. note::
+
+ the message from Linus below applies to 2.4 kernel. I have preserved it
+ for historical reasons, and because some of the information in it still
+ applies. Especially, please ignore any references to ksymoops.
+
+ ::
+
+ From: Linus Torvalds <torvalds@osdl.org>
+
+ How to track down an Oops.. [originally a mail to linux-kernel]
+
+ The main trick is having 5 years of experience with those pesky oops
+ messages ;-)
+
+Actually, there are things you can do that make this easier. I have two
+separate approaches::
+
+ gdb /usr/src/linux/vmlinux
+ gdb> disassemble <offending_function>
+
+That's the easy way to find the problem, at least if the bug-report is
+well made (like this one was - run through ``ksymoops`` to get the
+information of which function and the offset in the function that it
+happened in).
+
+Oh, it helps if the report happens on a kernel that is compiled with the
+same compiler and similar setups.
+
+The other thing to do is disassemble the "Code:" part of the bug report:
+ksymoops will do this too with the correct tools, but if you don't have
+the tools you can just do a silly program::
+
+ char str[] = "\xXX\xXX\xXX...";
+ main(){}
+
+and compile it with ``gcc -g`` and then do ``disassemble str`` (where the ``XX``
+stuff are the values reported by the Oops - you can just cut-and-paste
+and do a replace of spaces to ``\x`` - that's what I do, as I'm too lazy
+to write a program to automate this all).
+
+Alternatively, you can use the shell script in ``scripts/decodecode``.
+Its usage is::
+
+ decodecode < oops.txt
+
+The hex bytes that follow "Code:" may (in some architectures) have a series
+of bytes that precede the current instruction pointer as well as bytes at and
+following the current instruction pointer. In some cases, one instruction
+byte or word is surrounded by ``<>`` or ``()``, as in ``<86>`` or ``(f00d)``.
+These ``<>`` or ``()`` markings indicate the current instruction pointer.
+
+Example from i386, split into multiple lines for readability::
+
+ Code: f9 0f 8d f9 00 00 00 8d 42 0c e8 dd 26 11 c7 a1 60 ea 2b f9 8b 50 08 a1
+ 64 ea 2b f9 8d 34 82 8b 1e 85 db 74 6d 8b 15 60 ea 2b f9 <8b> 43 04 39 42 54
+ 7e 04 40 89 42 54 8b 43 04 3b 05 00 f6 52 c0
+
+Finally, if you want to see where the code comes from, you can do::
+
+ cd /usr/src/linux
+ make fs/buffer.s # or whatever file the bug happened in
+
+and then you get a better idea of what happens than with the gdb
+disassembly.
+
+Now, the trick is just then to combine all the data you have: the C
+sources (and general knowledge of what it **should** do), the assembly
+listing and the code disassembly (and additionally the register dump you
+also get from the "oops" message - that can be useful to see **what** the
+corrupted pointers were, and when you have the assembler listing you can
+also match the other registers to whatever C expressions they were used
+for).
+
+Essentially, you just look at what doesn't match (in this case it was the
+"Code" disassembly that didn't match with what the compiler generated).
+Then you need to find out **why** they don't match. Often it's simple - you
+see that the code uses a NULL pointer and then you look at the code and
+wonder how the NULL pointer got there, and if it's a valid thing to do
+you just check against it..
+
+Now, if somebody gets the idea that this is time-consuming and requires
+some small amount of concentration, you're right. Which is why I will
+mostly just ignore any panic reports that don't have the symbol table
+info etc looked up: it simply gets too hard to look it up (I have some
+programs to search for specific patterns in the kernel code segment, and
+sometimes I have been able to look up those kinds of panics too, but
+that really requires pretty good knowledge of the kernel just to be able
+to pick out the right sequences etc..)
+
+**Sometimes** it happens that I just see the disassembled code sequence
+from the panic, and I know immediately where it's coming from. That's when
+I get worried that I've been doing this for too long ;-)
+
+ Linus
+
+
+---------------------------------------------------------------------------
+
+Notes on Oops tracing with ``klogd``
+------------------------------------
+
+In order to help Linus and the other kernel developers there has been
+substantial support incorporated into ``klogd`` for processing protection
+faults. In order to have full support for address resolution at least
+version 1.3-pl3 of the ``sysklogd`` package should be used.
+
+When a protection fault occurs the ``klogd`` daemon automatically
+translates important addresses in the kernel log messages to their
+symbolic equivalents. This translated kernel message is then
+forwarded through whatever reporting mechanism ``klogd`` is using. The
+protection fault message can be simply cut out of the message files
+and forwarded to the kernel developers.
+
+Two types of address resolution are performed by ``klogd``. The first is
+static translation and the second is dynamic translation. Static
+translation uses the System.map file in much the same manner that
+ksymoops does. In order to do static translation the ``klogd`` daemon
+must be able to find a system map file at daemon initialization time.
+See the klogd man page for information on how ``klogd`` searches for map
+files.
+
+Dynamic address translation is important when kernel loadable modules
+are being used. Since memory for kernel modules is allocated from the
+kernel's dynamic memory pools there are no fixed locations for either
+the start of the module or for functions and symbols in the module.
+
+The kernel supports system calls which allow a program to determine
+which modules are loaded and their location in memory. Using these
+system calls the klogd daemon builds a symbol table which can be used
+to debug a protection fault which occurs in a loadable kernel module.
+
+At the very minimum klogd will provide the name of the module which
+generated the protection fault. There may be additional symbolic
+information available if the developer of the loadable module chose to
+export symbol information from the module.
+
+Since the kernel module environment can be dynamic there must be a
+mechanism for notifying the ``klogd`` daemon when a change in module
+environment occurs. There are command line options available which
+allow klogd to signal the currently executing daemon that symbol
+information should be refreshed. See the ``klogd`` manual page for more
+information.
+
+A patch is included with the sysklogd distribution which modifies the
+``modules-2.0.0`` package to automatically signal klogd whenever a module
+is loaded or unloaded. Applying this patch provides essentially
+seamless support for debugging protection faults which occur with
+kernel loadable modules.
+
+The following is an example of a protection fault in a loadable module
+processed by ``klogd``::
+
+ Aug 29 09:51:01 blizard kernel: Unable to handle kernel paging request at virtual address f15e97cc
+ Aug 29 09:51:01 blizard kernel: current->tss.cr3 = 0062d000, %cr3 = 0062d000
+ Aug 29 09:51:01 blizard kernel: *pde = 00000000
+ Aug 29 09:51:01 blizard kernel: Oops: 0002
+ Aug 29 09:51:01 blizard kernel: CPU: 0
+ Aug 29 09:51:01 blizard kernel: EIP: 0010:[oops:_oops+16/3868]
+ Aug 29 09:51:01 blizard kernel: EFLAGS: 00010212
+ Aug 29 09:51:01 blizard kernel: eax: 315e97cc ebx: 003a6f80 ecx: 001be77b edx: 00237c0c
+ Aug 29 09:51:01 blizard kernel: esi: 00000000 edi: bffffdb3 ebp: 00589f90 esp: 00589f8c
+ Aug 29 09:51:01 blizard kernel: ds: 0018 es: 0018 fs: 002b gs: 002b ss: 0018
+ Aug 29 09:51:01 blizard kernel: Process oops_test (pid: 3374, process nr: 21, stackpage=00589000)
+ Aug 29 09:51:01 blizard kernel: Stack: 315e97cc 00589f98 0100b0b4 bffffed4 0012e38e 00240c64 003a6f80 00000001
+ Aug 29 09:51:01 blizard kernel: 00000000 00237810 bfffff00 0010a7fa 00000003 00000001 00000000 bfffff00
+ Aug 29 09:51:01 blizard kernel: bffffdb3 bffffed4 ffffffda 0000002b 0007002b 0000002b 0000002b 00000036
+ Aug 29 09:51:01 blizard kernel: Call Trace: [oops:_oops_ioctl+48/80] [_sys_ioctl+254/272] [_system_call+82/128]
+ Aug 29 09:51:01 blizard kernel: Code: c7 00 05 00 00 00 eb 08 90 90 90 90 90 90 90 90 89 ec 5d c3
+
+---------------------------------------------------------------------------
+
+::
+
+ Dr. G.W. Wettstein Oncology Research Div. Computing Facility
+ Roger Maris Cancer Center INTERNET: greg@wind.rmcc.com
+ 820 4th St. N.
+ Fargo, ND 58122
+ Phone: 701-234-7556
+
+
+---------------------------------------------------------------------------
+
+Tainted kernels
+---------------
+
+Some oops reports contain the string **'Tainted: '** after the program
+counter. This indicates that the kernel has been tainted by some
+mechanism. The string is followed by a series of position-sensitive
+characters, each representing a particular tainted value.
+
+ 1) 'G' if all modules loaded have a GPL or compatible license, 'P' if
+ any proprietary module has been loaded. Modules without a
+ MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
+ insmod as GPL compatible are assumed to be proprietary.
+
+ 2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
+ modules were loaded normally.
+
+ 3) ``S`` if the oops occurred on an SMP kernel running on hardware that
+ hasn't been certified as safe to run multiprocessor.
+ Currently this occurs only on various Athlons that are not
+ SMP capable.
+
+ 4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
+ modules were unloaded normally.
+
+ 5) ``M`` if any processor has reported a Machine Check Exception,
+ ``' '`` if no Machine Check Exceptions have occurred.
+
+ 6) ``B`` if a page-release function has found a bad page reference or
+ some unexpected page flags.
+
+ 7) ``U`` if a user or user application specifically requested that the
+ Tainted flag be set, ``' '`` otherwise.
+
+ 8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
+
+ 9) ``A`` if the ACPI table has been overridden.
+
+ 10) ``W`` if a warning has previously been issued by the kernel.
+ (Though some warnings may set more specific taint flags.)
+
+ 11) ``C`` if a staging driver has been loaded.
+
+ 12) ``I`` if the kernel is working around a severe bug in the platform
+ firmware (BIOS or similar).
+
+ 13) ``O`` if an externally-built ("out-of-tree") module has been loaded.
+
+ 14) ``E`` if an unsigned module has been loaded in a kernel supporting
+ module signature.
+
+ 15) ``L`` if a soft lockup has previously occurred on the system.
+
+ 16) ``K`` if the kernel has been live patched.
+
+The primary reason for the **'Tainted: '** string is to tell kernel
+debuggers if this is a clean kernel or if anything unusual has
+occurred. Tainting is permanent: even if an offending module is
+unloaded, the tainted value remains to indicate that the kernel is not
+trustworthy.
--- /dev/null
+Parport
++++++++
+
+The ``parport`` code provides parallel-port support under Linux. This
+includes the ability to share one port between multiple device
+drivers.
+
+You can pass parameters to the ``parport`` code to override its automatic
+detection of your hardware. This is particularly useful if you want
+to use IRQs, since in general these can't be autoprobed successfully.
+By default IRQs are not used even if they **can** be probed. This is
+because there are a lot of people using the same IRQ for their
+parallel port and a sound card or network card.
+
+The ``parport`` code is split into two parts: generic (which deals with
+port-sharing) and architecture-dependent (which deals with actually
+using the port).
+
+
+Parport as modules
+==================
+
+If you load the `parport`` code as a module, say::
+
+ # insmod parport
+
+to load the generic ``parport`` code. You then must load the
+architecture-dependent code with (for example)::
+
+ # insmod parport_pc io=0x3bc,0x378,0x278 irq=none,7,auto
+
+to tell the ``parport`` code that you want three PC-style ports, one at
+0x3bc with no IRQ, one at 0x378 using IRQ 7, and one at 0x278 with an
+auto-detected IRQ. Currently, PC-style (``parport_pc``), Sun ``bpp``,
+Amiga, Atari, and MFC3 hardware is supported.
+
+PCI parallel I/O card support comes from ``parport_pc``. Base I/O
+addresses should not be specified for supported PCI cards since they
+are automatically detected.
+
+
+modprobe
+--------
+
+If you use modprobe , you will find it useful to add lines as below to a
+configuration file in /etc/modprobe.d/ directory::
+
+ alias parport_lowlevel parport_pc
+ options parport_pc io=0x378,0x278 irq=7,auto
+
+modprobe will load ``parport_pc`` (with the options ``io=0x378,0x278 irq=7,auto``)
+whenever a parallel port device driver (such as ``lp``) is loaded.
+
+Note that these are example lines only! You shouldn't in general need
+to specify any options to ``parport_pc`` in order to be able to use a
+parallel port.
+
+
+Parport probe [optional]
+------------------------
+
+In 2.2 kernels there was a module called ``parport_probe``, which was used
+for collecting IEEE 1284 device ID information. This has now been
+enhanced and now lives with the IEEE 1284 support. When a parallel
+port is detected, the devices that are connected to it are analysed,
+and information is logged like this::
+
+ parport0: Printer, BJC-210 (Canon)
+
+The probe information is available from files in ``/proc/sys/dev/parport/``.
+
+
+Parport linked into the kernel statically
+=========================================
+
+If you compile the ``parport`` code into the kernel, then you can use
+kernel boot parameters to get the same effect. Add something like the
+following to your LILO command line::
+
+ parport=0x3bc parport=0x378,7 parport=0x278,auto,nofifo
+
+You can have many ``parport=...`` statements, one for each port you want
+to add. Adding ``parport=0`` to the kernel command-line will disable
+parport support entirely. Adding ``parport=auto`` to the kernel
+command-line will make ``parport`` use any IRQ lines or DMA channels that
+it auto-detects.
+
+
+Files in /proc
+==============
+
+If you have configured the ``/proc`` filesystem into your kernel, you will
+see a new directory entry: ``/proc/sys/dev/parport``. In there will be a
+directory entry for each parallel port for which parport is
+configured. In each of those directories are a collection of files
+describing that parallel port.
+
+The ``/proc/sys/dev/parport`` directory tree looks like::
+
+ parport
+ |-- default
+ | |-- spintime
+ | `-- timeslice
+ |-- parport0
+ | |-- autoprobe
+ | |-- autoprobe0
+ | |-- autoprobe1
+ | |-- autoprobe2
+ | |-- autoprobe3
+ | |-- devices
+ | | |-- active
+ | | `-- lp
+ | | `-- timeslice
+ | |-- base-addr
+ | |-- irq
+ | |-- dma
+ | |-- modes
+ | `-- spintime
+ `-- parport1
+ |-- autoprobe
+ |-- autoprobe0
+ |-- autoprobe1
+ |-- autoprobe2
+ |-- autoprobe3
+ |-- devices
+ | |-- active
+ | `-- ppa
+ | `-- timeslice
+ |-- base-addr
+ |-- irq
+ |-- dma
+ |-- modes
+ `-- spintime
+
+.. tabularcolumns:: |p{4.0cm}|p{13.5cm}|
+
+======================= =======================================================
+File Contents
+======================= =======================================================
+``devices/active`` A list of the device drivers using that port. A "+"
+ will appear by the name of the device currently using
+ the port (it might not appear against any). The
+ string "none" means that there are no device drivers
+ using that port.
+
+``base-addr`` Parallel port's base address, or addresses if the port
+ has more than one in which case they are separated
+ with tabs. These values might not have any sensible
+ meaning for some ports.
+
+``irq`` Parallel port's IRQ, or -1 if none is being used.
+
+``dma`` Parallel port's DMA channel, or -1 if none is being
+ used.
+
+``modes`` Parallel port's hardware modes, comma-separated,
+ meaning:
+
+ - PCSPP
+ PC-style SPP registers are available.
+
+ - TRISTATE
+ Port is bidirectional.
+
+ - COMPAT
+ Hardware acceleration for printers is
+ available and will be used.
+
+ - EPP
+ Hardware acceleration for EPP protocol
+ is available and will be used.
+
+ - ECP
+ Hardware acceleration for ECP protocol
+ is available and will be used.
+
+ - DMA
+ DMA is available and will be used.
+
+ Note that the current implementation will only take
+ advantage of COMPAT and ECP modes if it has an IRQ
+ line to use.
+
+``autoprobe`` Any IEEE-1284 device ID information that has been
+ acquired from the (non-IEEE 1284.3) device.
+
+``autoprobe[0-3]`` IEEE 1284 device ID information retrieved from
+ daisy-chain devices that conform to IEEE 1284.3.
+
+``spintime`` The number of microseconds to busy-loop while waiting
+ for the peripheral to respond. You might find that
+ adjusting this improves performance, depending on your
+ peripherals. This is a port-wide setting, i.e. it
+ applies to all devices on a particular port.
+
+``timeslice`` The number of milliseconds that a device driver is
+ allowed to keep a port claimed for. This is advisory,
+ and driver can ignore it if it must.
+
+``default/*`` The defaults for spintime and timeslice. When a new
+ port is registered, it picks up the default spintime.
+ When a new device is registered, it picks up the
+ default timeslice.
+======================= =======================================================
+
+Device drivers
+==============
+
+Once the parport code is initialised, you can attach device drivers to
+specific ports. Normally this happens automatically; if the lp driver
+is loaded it will create one lp device for each port found. You can
+override this, though, by using parameters either when you load the lp
+driver::
+
+ # insmod lp parport=0,2
+
+or on the LILO command line::
+
+ lp=parport0 lp=parport2
+
+Both the above examples would inform lp that you want ``/dev/lp0`` to be
+the first parallel port, and /dev/lp1 to be the **third** parallel port,
+with no lp device associated with the second port (parport1). Note
+that this is different to the way older kernels worked; there used to
+be a static association between the I/O port address and the device
+name, so ``/dev/lp0`` was always the port at 0x3bc. This is no longer the
+case - if you only have one port, it will default to being ``/dev/lp0``,
+regardless of base address.
+
+Also:
+
+ * If you selected the IEEE 1284 support at compile time, you can say
+ ``lp=auto`` on the kernel command line, and lp will create devices
+ only for those ports that seem to have printers attached.
+
+ * If you give PLIP the ``timid`` parameter, either with ``plip=timid`` on
+ the command line, or with ``insmod plip timid=1`` when using modules,
+ it will avoid any ports that seem to be in use by other devices.
+
+ * IRQ autoprobing works only for a few port types at the moment.
+
+Reporting printer problems with parport
+=======================================
+
+If you are having problems printing, please go through these steps to
+try to narrow down where the problem area is.
+
+When reporting problems with parport, really you need to give all of
+the messages that ``parport_pc`` spits out when it initialises. There are
+several code paths:
+
+- polling
+- interrupt-driven, protocol in software
+- interrupt-driven, protocol in hardware using PIO
+- interrupt-driven, protocol in hardware using DMA
+
+The kernel messages that ``parport_pc`` logs give an indication of which
+code path is being used. (They could be a lot better actually..)
+
+For normal printer protocol, having IEEE 1284 modes enabled or not
+should not make a difference.
+
+To turn off the 'protocol in hardware' code paths, disable
+``CONFIG_PARPORT_PC_FIFO``. Note that when they are enabled they are not
+necessarily **used**; it depends on whether the hardware is available,
+enabled by the BIOS, and detected by the driver.
+
+So, to start with, disable ``CONFIG_PARPORT_PC_FIFO``, and load ``parport_pc``
+with ``irq=none``. See if printing works then. It really should,
+because this is the simplest code path.
+
+If that works fine, try with ``io=0x378 irq=7`` (adjust for your
+hardware), to make it use interrupt-driven in-software protocol.
+
+If **that** works fine, then one of the hardware modes isn't working
+right. Enable ``CONFIG_FIFO`` (no, it isn't a module option,
+and yes, it should be), set the port to ECP mode in the BIOS and note
+the DMA channel, and try with::
+
+ io=0x378 irq=7 dma=none (for PIO)
+ io=0x378 irq=7 dma=3 (for DMA)
+
+----------
+
+philb@gnu.org
+tim@cyberelk.net
--- /dev/null
+Ramoops oops/panic logger
+=========================
+
+Sergiu Iordache <sergiu@chromium.org>
+
+Updated: 17 November 2011
+
+Introduction
+------------
+
+Ramoops is an oops/panic logger that writes its logs to RAM before the system
+crashes. It works by logging oopses and panics in a circular buffer. Ramoops
+needs a system with persistent RAM so that the content of that area can
+survive after a restart.
+
+Ramoops concepts
+----------------
+
+Ramoops uses a predefined memory area to store the dump. The start and size
+and type of the memory area are set using three variables:
+
+ * ``mem_address`` for the start
+ * ``mem_size`` for the size. The memory size will be rounded down to a
+ power of two.
+ * ``mem_type`` to specifiy if the memory type (default is pgprot_writecombine).
+
+Typically the default value of ``mem_type=0`` should be used as that sets the pstore
+mapping to pgprot_writecombine. Setting ``mem_type=1`` attempts to use
+``pgprot_noncached``, which only works on some platforms. This is because pstore
+depends on atomic operations. At least on ARM, pgprot_noncached causes the
+memory to be mapped strongly ordered, and atomic operations on strongly ordered
+memory are implementation defined, and won't work on many ARMs such as omaps.
+
+The memory area is divided into ``record_size`` chunks (also rounded down to
+power of two) and each oops/panic writes a ``record_size`` chunk of
+information.
+
+Dumping both oopses and panics can be done by setting 1 in the ``dump_oops``
+variable while setting 0 in that variable dumps only the panics.
+
+The module uses a counter to record multiple dumps but the counter gets reset
+on restart (i.e. new dumps after the restart will overwrite old ones).
+
+Ramoops also supports software ECC protection of persistent memory regions.
+This might be useful when a hardware reset was used to bring the machine back
+to life (i.e. a watchdog triggered). In such cases, RAM may be somewhat
+corrupt, but usually it is restorable.
+
+Setting the parameters
+----------------------
+
+Setting the ramoops parameters can be done in several different manners:
+
+ A. Use the module parameters (which have the names of the variables described
+ as before). For quick debugging, you can also reserve parts of memory during
+ boot and then use the reserved memory for ramoops. For example, assuming a
+ machine with > 128 MB of memory, the following kernel command line will tell
+ the kernel to use only the first 128 MB of memory, and place ECC-protected
+ ramoops region at 128 MB boundary::
+
+ mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1
+
+ B. Use Device Tree bindings, as described in
+ ``Documentation/device-tree/bindings/reserved-memory/ramoops.txt``.
+ For example::
+
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ ranges;
+
+ ramoops@8f000000 {
+ compatible = "ramoops";
+ reg = <0 0x8f000000 0 0x100000>;
+ record-size = <0x4000>;
+ console-size = <0x4000>;
+ };
+ };
+
+ C. Use a platform device and set the platform data. The parameters can then
+ be set through that platform data. An example of doing that is::
+
+ #include <linux/pstore_ram.h>
+ [...]
+
+ static struct ramoops_platform_data ramoops_data = {
+ .mem_size = <...>,
+ .mem_address = <...>,
+ .mem_type = <...>,
+ .record_size = <...>,
+ .dump_oops = <...>,
+ .ecc = <...>,
+ };
+
+ static struct platform_device ramoops_dev = {
+ .name = "ramoops",
+ .dev = {
+ .platform_data = &ramoops_data,
+ },
+ };
+
+ [... inside a function ...]
+ int ret;
+
+ ret = platform_device_register(&ramoops_dev);
+ if (ret) {
+ printk(KERN_ERR "unable to register platform device\n");
+ return ret;
+ }
+
+You can specify either RAM memory or peripheral devices' memory. However, when
+specifying RAM, be sure to reserve the memory by issuing memblock_reserve()
+very early in the architecture code, e.g.::
+
+ #include <linux/memblock.h>
+
+ memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
+
+Dump format
+-----------
+
+The data dump begins with a header, currently defined as ``====`` followed by a
+timestamp and a new line. The dump then continues with the actual data.
+
+Reading the data
+----------------
+
+The dump data can be read from the pstore filesystem. The format for these
+files is ``dmesg-ramoops-N``, where N is the record number in memory. To delete
+a stored record from RAM, simply unlink the respective pstore file.
+
+Persistent function tracing
+---------------------------
+
+Persistent function tracing might be useful for debugging software or hardware
+related hangs. The functions call chain log is stored in a ``ftrace-ramoops``
+file. Here is an example of usage::
+
+ # mount -t debugfs debugfs /sys/kernel/debug/
+ # echo 1 > /sys/kernel/debug/pstore/record_ftrace
+ # reboot -f
+ [...]
+ # mount -t pstore pstore /mnt/
+ # tail /mnt/ftrace-ramoops
+ 0 ffffffff8101ea64 ffffffff8101bcda native_apic_mem_read <- disconnect_bsp_APIC+0x6a/0xc0
+ 0 ffffffff8101ea44 ffffffff8101bcf6 native_apic_mem_write <- disconnect_bsp_APIC+0x86/0xc0
+ 0 ffffffff81020084 ffffffff8101a4b5 hpet_disable <- native_machine_shutdown+0x75/0x90
+ 0 ffffffff81005f94 ffffffff8101a4bb iommu_shutdown_noop <- native_machine_shutdown+0x7b/0x90
+ 0 ffffffff8101a6a1 ffffffff8101a437 native_machine_emergency_restart <- native_machine_restart+0x37/0x40
+ 0 ffffffff811f9876 ffffffff8101a73a acpi_reboot <- native_machine_emergency_restart+0xaa/0x1e0
+ 0 ffffffff8101a514 ffffffff8101a772 mach_reboot_fixups <- native_machine_emergency_restart+0xe2/0x1e0
+ 0 ffffffff811d9c54 ffffffff8101a7a0 __const_udelay <- native_machine_emergency_restart+0x110/0x1e0
+ 0 ffffffff811d9c34 ffffffff811d9c80 __delay <- __const_udelay+0x30/0x40
+ 0 ffffffff811d9d14 ffffffff811d9c3f delay_tsc <- __delay+0xf/0x20
--- /dev/null
+.. _reportingbugs:
+
+Reporting bugs
+++++++++++++++
+
+Background
+==========
+
+The upstream Linux kernel maintainers only fix bugs for specific kernel
+versions. Those versions include the current "release candidate" (or -rc)
+kernel, any "stable" kernel versions, and any "long term" kernels.
+
+Please see https://www.kernel.org/ for a list of supported kernels. Any
+kernel marked with [EOL] is "end of life" and will not have any fixes
+backported to it.
+
+If you've found a bug on a kernel version that isn't listed on kernel.org,
+contact your Linux distribution or embedded vendor for support.
+Alternatively, you can attempt to run one of the supported stable or -rc
+kernels, and see if you can reproduce the bug on that. It's preferable
+to reproduce the bug on the latest -rc kernel.
+
+
+How to report Linux kernel bugs
+===============================
+
+
+Identify the problematic subsystem
+----------------------------------
+
+Identifying which part of the Linux kernel might be causing your issue
+increases your chances of getting your bug fixed. Simply posting to the
+generic linux-kernel mailing list (LKML) may cause your bug report to be
+lost in the noise of a mailing list that gets 1000+ emails a day.
+
+Instead, try to figure out which kernel subsystem is causing the issue,
+and email that subsystem's maintainer and mailing list. If the subsystem
+maintainer doesn't answer, then expand your scope to mailing lists like
+LKML.
+
+
+Identify who to notify
+----------------------
+
+Once you know the subsystem that is causing the issue, you should send a
+bug report. Some maintainers prefer bugs to be reported via bugzilla
+(https://bugzilla.kernel.org), while others prefer that bugs be reported
+via the subsystem mailing list.
+
+To find out where to send an emailed bug report, find your subsystem or
+device driver in the MAINTAINERS file. Search in the file for relevant
+entries, and send your bug report to the person(s) listed in the "M:"
+lines, making sure to Cc the mailing list(s) in the "L:" lines. When the
+maintainer replies to you, make sure to 'Reply-all' in order to keep the
+public mailing list(s) in the email thread.
+
+If you know which driver is causing issues, you can pass one of the driver
+files to the get_maintainer.pl script::
+
+ perl scripts/get_maintainer.pl -f <filename>
+
+If it is a security bug, please copy the Security Contact listed in the
+MAINTAINERS file. They can help coordinate bugfix and disclosure. See
+:ref:`Documentation/SecurityBugs <securitybugs>` for more information.
+
+If you can't figure out which subsystem caused the issue, you should file
+a bug in kernel.org bugzilla and send email to
+linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more
+information on the linux-kernel mailing list see
+http://www.tux.org/lkml/).
+
+
+Tips for reporting bugs
+-----------------------
+
+If you haven't reported a bug before, please read:
+
+ http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
+
+ http://www.catb.org/esr/faqs/smart-questions.html
+
+It's REALLY important to report bugs that seem unrelated as separate email
+threads or separate bugzilla entries. If you report several unrelated
+bugs at once, it's difficult for maintainers to tease apart the relevant
+data.
+
+
+Gather information
+------------------
+
+The most important information in a bug report is how to reproduce the
+bug. This includes system information, and (most importantly)
+step-by-step instructions for how a user can trigger the bug.
+
+If the failure includes an "OOPS:", take a picture of the screen, capture
+a netconsole trace, or type the message from your screen into the bug
+report. Please read "Documentation/oops-tracing.txt" before posting your
+bug report. This explains what you should do with the "Oops" information
+to make it useful to the recipient.
+
+This is a suggested format for a bug report sent via email or bugzilla.
+Having a standardized bug report form makes it easier for you not to
+overlook things, and easier for the developers to find the pieces of
+information they're really interested in. If some information is not
+relevant to your bug, feel free to exclude it.
+
+First run the ver_linux script included as scripts/ver_linux, which
+reports the version of some important subsystems. Run this script with
+the command ``sh scripts/ver_linux``.
+
+Use that information to fill in all fields of the bug report form, and
+post it to the mailing list with a subject of "PROBLEM: <one line
+summary from [1.]>" for easy identification by the developers::
+
+ [1.] One line summary of the problem:
+ [2.] Full description of the problem/report:
+ [3.] Keywords (i.e., modules, networking, kernel):
+ [4.] Kernel information
+ [4.1.] Kernel version (from /proc/version):
+ [4.2.] Kernel .config file:
+ [5.] Most recent kernel version which did not have the bug:
+ [6.] Output of Oops.. message (if applicable) with symbolic information
+ resolved (see Documentation/oops-tracing.txt)
+ [7.] A small shell script or example program which triggers the
+ problem (if possible)
+ [8.] Environment
+ [8.1.] Software (add the output of the ver_linux script here)
+ [8.2.] Processor information (from /proc/cpuinfo):
+ [8.3.] Module information (from /proc/modules):
+ [8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
+ [8.5.] PCI information ('lspci -vvv' as root)
+ [8.6.] SCSI information (from /proc/scsi/scsi)
+ [8.7.] Other information that might be relevant to the problem
+ (please look in /proc and include all information that you
+ think to be relevant):
+ [X.] Other notes, patches, fixes, workarounds:
+
+
+Follow up
+=========
+
+Expectations for bug reporters
+------------------------------
+
+Linux kernel maintainers expect bug reporters to be able to follow up on
+bug reports. That may include running new tests, applying patches,
+recompiling your kernel, and/or re-triggering your bug. The most
+frustrating thing for maintainers is for someone to report a bug, and then
+never follow up on a request to try out a fix.
+
+That said, it's still useful for a kernel maintainer to know a bug exists
+on a supported kernel, even if you can't follow up with retests. Follow
+up reports, such as replying to the email thread with "I tried the latest
+kernel and I can't reproduce my bug anymore" are also helpful, because
+maintainers have to assume silence means things are still broken.
+
+Expectations for kernel maintainers
+-----------------------------------
+
+Linux kernel maintainers are busy, overworked human beings. Some times
+they may not be able to address your bug in a day, a week, or two weeks.
+If they don't answer your email, they may be on vacation, or at a Linux
+conference. Check the conference schedule at https://LWN.net for more info:
+
+ https://lwn.net/Calendar/
+
+In general, kernel maintainers take 1 to 5 business days to respond to
+bugs. The majority of kernel maintainers are employed to work on the
+kernel, and they may not work on the weekends. Maintainers are scattered
+around the world, and they may not work in your time zone. Unless you
+have a high priority bug, please wait at least a week after the first bug
+report before sending the maintainer a reminder email.
+
+The exceptions to this rule are regressions, kernel crashes, security holes,
+or userspace breakage caused by new kernel behavior. Those bugs should be
+addressed by the maintainers ASAP. If you suspect a maintainer is not
+responding to these types of bugs in a timely manner (especially during a
+merge window), escalate the bug to LKML and Linus Torvalds.
+
+Thank you!
+
+[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]
--- /dev/null
+.. _securitybugs:
+
+Security bugs
+=============
+
+Linux kernel developers take security very seriously. As such, we'd
+like to know when a security bug is found so that it can be fixed and
+disclosed as quickly as possible. Please report security bugs to the
+Linux kernel security team.
+
+Contact
+-------
+
+The Linux kernel security team can be contacted by email at
+<security@kernel.org>. This is a private list of security officers
+who will help verify the bug report and develop and release a fix.
+It is possible that the security team will bring in extra help from
+area maintainers to understand and fix the security vulnerability.
+
+As it is with any bug, the more information provided the easier it
+will be to diagnose and fix. Please review the procedure outlined in
+REPORTING-BUGS if you are unclear about what information is helpful.
+Any exploit code is very helpful and will not be released without
+consent from the reporter unless it has already been made public.
+
+Disclosure
+----------
+
+The goal of the Linux kernel security team is to work with the
+bug submitter to bug resolution as well as disclosure. We prefer
+to fully disclose the bug as soon as possible. It is reasonable to
+delay disclosure when the bug or the fix is not yet fully understood,
+the solution is not well-tested or for vendor coordination. However, we
+expect these delays to be short, measurable in days, not weeks or months.
+A disclosure date is negotiated by the security team working with the
+bug submitter as well as vendors. However, the kernel security team
+holds the final say when setting a disclosure date. The timeframe for
+disclosure is from immediate (esp. if it's already publicly known)
+to a few weeks. As a basic default policy, we expect report date to
+disclosure date to be on the order of 7 days.
+
+Non-disclosure agreements
+-------------------------
+
+The Linux kernel security team is not a formal body and therefore unable
+to enter any non-disclosure agreements.
--- /dev/null
+.. _serial_console:
+
+Linux Serial Console
+====================
+
+To use a serial port as console you need to compile the support into your
+kernel - by default it is not compiled in. For PC style serial ports
+it's the config option next to menu option:
+
+:menuselection:`Character devices --> Serial drivers --> 8250/16550 and compatible serial support --> Console on 8250/16550 and compatible serial port`
+
+You must compile serial support into the kernel and not as a module.
+
+It is possible to specify multiple devices for console output. You can
+define a new kernel command line option to select which device(s) to
+use for console output.
+
+The format of this option is::
+
+ console=device,options
+
+ device: tty0 for the foreground virtual console
+ ttyX for any other virtual console
+ ttySx for a serial port
+ lp0 for the first parallel port
+ ttyUSB0 for the first USB serial device
+
+ options: depend on the driver. For the serial port this
+ defines the baudrate/parity/bits/flow control of
+ the port, in the format BBBBPNF, where BBBB is the
+ speed, P is parity (n/o/e), N is number of bits,
+ and F is flow control ('r' for RTS). Default is
+ 9600n8. The maximum baudrate is 115200.
+
+You can specify multiple console= options on the kernel command line.
+Output will appear on all of them. The last device will be used when
+you open ``/dev/console``. So, for example::
+
+ console=ttyS1,9600 console=tty0
+
+defines that opening ``/dev/console`` will get you the current foreground
+virtual console, and kernel messages will appear on both the VGA
+console and the 2nd serial port (ttyS1 or COM2) at 9600 baud.
+
+Note that you can only define one console per device type (serial, video).
+
+If no console device is specified, the first device found capable of
+acting as a system console will be used. At this time, the system
+first looks for a VGA card and then for a serial port. So if you don't
+have a VGA card in your system the first serial port will automatically
+become the console.
+
+You will need to create a new device to use ``/dev/console``. The official
+``/dev/console`` is now character device 5,1.
+
+(You can also use a network device as a console. See
+``Documentation/networking/netconsole.txt`` for information on that.)
+
+Here's an example that will use ``/dev/ttyS1`` (COM2) as the console.
+Replace the sample values as needed.
+
+1. Create ``/dev/console`` (real console) and ``/dev/tty0`` (master virtual
+ console)::
+
+ cd /dev
+ rm -f console tty0
+ mknod -m 622 console c 5 1
+ mknod -m 622 tty0 c 4 0
+
+2. LILO can also take input from a serial device. This is a very
+ useful option. To tell LILO to use the serial port:
+ In lilo.conf (global section)::
+
+ serial = 1,9600n8 (ttyS1, 9600 bd, no parity, 8 bits)
+
+3. Adjust to kernel flags for the new kernel,
+ again in lilo.conf (kernel section)::
+
+ append = "console=ttyS1,9600"
+
+4. Make sure a getty runs on the serial port so that you can login to
+ it once the system is done booting. This is done by adding a line
+ like this to ``/etc/inittab`` (exact syntax depends on your getty)::
+
+ S1:23:respawn:/sbin/getty -L ttyS1 9600 vt100
+
+5. Init and ``/etc/ioctl.save``
+
+ Sysvinit remembers its stty settings in a file in ``/etc``, called
+ ``/etc/ioctl.save``. REMOVE THIS FILE before using the serial
+ console for the first time, because otherwise init will probably
+ set the baudrate to 38400 (baudrate of the virtual console).
+
+6. ``/dev/console`` and X
+ Programs that want to do something with the virtual console usually
+ open ``/dev/console``. If you have created the new ``/dev/console`` device,
+ and your console is NOT the virtual console some programs will fail.
+ Those are programs that want to access the VT interface, and use
+ ``/dev/console instead of /dev/tty0``. Some of those programs are::
+
+ Xfree86, svgalib, gpm, SVGATextMode
+
+ It should be fixed in modern versions of these programs though.
+
+ Note that if you boot without a ``console=`` option (or with
+ ``console=/dev/tty0``), ``/dev/console`` is the same as ``/dev/tty0``.
+ In that case everything will still work.
+
+7. Thanks
+
+ Thanks to Geert Uytterhoeven <geert@linux-m68k.org>
+ for porting the patches from 2.1.4x to 2.1.6x for taking care of
+ the integration of these patches into m68k, ppc and alpha.
+
+Miquel van Smoorenburg <miquels@cistron.nl>, 11-Jun-2000
--- /dev/null
+Rules on how to access information in the Linux kernel sysfs
+============================================================
+
+The kernel-exported sysfs exports internal kernel implementation details
+and depends on internal kernel structures and layout. It is agreed upon
+by the kernel developers that the Linux kernel does not provide a stable
+internal API. Therefore, there are aspects of the sysfs interface that
+may not be stable across kernel releases.
+
+To minimize the risk of breaking users of sysfs, which are in most cases
+low-level userspace applications, with a new kernel release, the users
+of sysfs must follow some rules to use an as-abstract-as-possible way to
+access this filesystem. The current udev and HAL programs already
+implement this and users are encouraged to plug, if possible, into the
+abstractions these programs provide instead of accessing sysfs directly.
+
+But if you really do want or need to access sysfs directly, please follow
+the following rules and then your programs should work with future
+versions of the sysfs interface.
+
+- Do not use libsysfs
+ It makes assumptions about sysfs which are not true. Its API does not
+ offer any abstraction, it exposes all the kernel driver-core
+ implementation details in its own API. Therefore it is not better than
+ reading directories and opening the files yourself.
+ Also, it is not actively maintained, in the sense of reflecting the
+ current kernel development. The goal of providing a stable interface
+ to sysfs has failed; it causes more problems than it solves. It
+ violates many of the rules in this document.
+
+- sysfs is always at ``/sys``
+ Parsing ``/proc/mounts`` is a waste of time. Other mount points are a
+ system configuration bug you should not try to solve. For test cases,
+ possibly support a ``SYSFS_PATH`` environment variable to overwrite the
+ application's behavior, but never try to search for sysfs. Never try
+ to mount it, if you are not an early boot script.
+
+- devices are only "devices"
+ There is no such thing like class-, bus-, physical devices,
+ interfaces, and such that you can rely on in userspace. Everything is
+ just simply a "device". Class-, bus-, physical, ... types are just
+ kernel implementation details which should not be expected by
+ applications that look for devices in sysfs.
+
+ The properties of a device are:
+
+ - devpath (``/devices/pci0000:00/0000:00:1d.1/usb2/2-2/2-2:1.0``)
+
+ - identical to the DEVPATH value in the event sent from the kernel
+ at device creation and removal
+ - the unique key to the device at that point in time
+ - the kernel's path to the device directory without the leading
+ ``/sys``, and always starting with a slash
+ - all elements of a devpath must be real directories. Symlinks
+ pointing to /sys/devices must always be resolved to their real
+ target and the target path must be used to access the device.
+ That way the devpath to the device matches the devpath of the
+ kernel used at event time.
+ - using or exposing symlink values as elements in a devpath string
+ is a bug in the application
+
+ - kernel name (``sda``, ``tty``, ``0000:00:1f.2``, ...)
+
+ - a directory name, identical to the last element of the devpath
+ - applications need to handle spaces and characters like ``!`` in
+ the name
+
+ - subsystem (``block``, ``tty``, ``pci``, ...)
+
+ - simple string, never a path or a link
+ - retrieved by reading the "subsystem"-link and using only the
+ last element of the target path
+
+ - driver (``tg3``, ``ata_piix``, ``uhci_hcd``)
+
+ - a simple string, which may contain spaces, never a path or a
+ link
+ - it is retrieved by reading the "driver"-link and using only the
+ last element of the target path
+ - devices which do not have "driver"-link just do not have a
+ driver; copying the driver value in a child device context is a
+ bug in the application
+
+ - attributes
+
+ - the files in the device directory or files below subdirectories
+ of the same device directory
+ - accessing attributes reached by a symlink pointing to another device,
+ like the "device"-link, is a bug in the application
+
+ Everything else is just a kernel driver-core implementation detail
+ that should not be assumed to be stable across kernel releases.
+
+- Properties of parent devices never belong into a child device.
+ Always look at the parent devices themselves for determining device
+ context properties. If the device ``eth0`` or ``sda`` does not have a
+ "driver"-link, then this device does not have a driver. Its value is empty.
+ Never copy any property of the parent-device into a child-device. Parent
+ device properties may change dynamically without any notice to the
+ child device.
+
+- Hierarchy in a single device tree
+ There is only one valid place in sysfs where hierarchy can be examined
+ and this is below: ``/sys/devices.``
+ It is planned that all device directories will end up in the tree
+ below this directory.
+
+- Classification by subsystem
+ There are currently three places for classification of devices:
+ ``/sys/block,`` ``/sys/class`` and ``/sys/bus.`` It is planned that these will
+ not contain any device directories themselves, but only flat lists of
+ symlinks pointing to the unified ``/sys/devices`` tree.
+ All three places have completely different rules on how to access
+ device information. It is planned to merge all three
+ classification directories into one place at ``/sys/subsystem``,
+ following the layout of the bus directories. All buses and
+ classes, including the converted block subsystem, will show up
+ there.
+ The devices belonging to a subsystem will create a symlink in the
+ "devices" directory at ``/sys/subsystem/<name>/devices``,
+
+ If ``/sys/subsystem`` exists, ``/sys/bus``, ``/sys/class`` and ``/sys/block``
+ can be ignored. If it does not exist, you always have to scan all three
+ places, as the kernel is free to move a subsystem from one place to
+ the other, as long as the devices are still reachable by the same
+ subsystem name.
+
+ Assuming ``/sys/class/<subsystem>`` and ``/sys/bus/<subsystem>``, or
+ ``/sys/block`` and ``/sys/class/block`` are not interchangeable is a bug in
+ the application.
+
+- Block
+ The converted block subsystem at ``/sys/class/block`` or
+ ``/sys/subsystem/block`` will contain the links for disks and partitions
+ at the same level, never in a hierarchy. Assuming the block subsystem to
+ contain only disks and not partition devices in the same flat list is
+ a bug in the application.
+
+- "device"-link and <subsystem>:<kernel name>-links
+ Never depend on the "device"-link. The "device"-link is a workaround
+ for the old layout, where class devices are not created in
+ ``/sys/devices/`` like the bus devices. If the link-resolving of a
+ device directory does not end in ``/sys/devices/``, you can use the
+ "device"-link to find the parent devices in ``/sys/devices/``, That is the
+ single valid use of the "device"-link; it must never appear in any
+ path as an element. Assuming the existence of the "device"-link for
+ a device in ``/sys/devices/`` is a bug in the application.
+ Accessing ``/sys/class/net/eth0/device`` is a bug in the application.
+
+ Never depend on the class-specific links back to the ``/sys/class``
+ directory. These links are also a workaround for the design mistake
+ that class devices are not created in ``/sys/devices.`` If a device
+ directory does not contain directories for child devices, these links
+ may be used to find the child devices in ``/sys/class.`` That is the single
+ valid use of these links; they must never appear in any path as an
+ element. Assuming the existence of these links for devices which are
+ real child device directories in the ``/sys/devices`` tree is a bug in
+ the application.
+
+ It is planned to remove all these links when all class device
+ directories live in ``/sys/devices.``
+
+- Position of devices along device chain can change.
+ Never depend on a specific parent device position in the devpath,
+ or the chain of parent devices. The kernel is free to insert devices into
+ the chain. You must always request the parent device you are looking for
+ by its subsystem value. You need to walk up the chain until you find
+ the device that matches the expected subsystem. Depending on a specific
+ position of a parent device or exposing relative paths using ``../`` to
+ access the chain of parents is a bug in the application.
+
+- When reading and writing sysfs device attribute files, avoid dependency
+ on specific error codes wherever possible. This minimizes coupling to
+ the error handling implementation within the kernel.
+
+ In general, failures to read or write sysfs device attributes shall
+ propagate errors wherever possible. Common errors include, but are not
+ limited to:
+
+ ``-EIO``: The read or store operation is not supported, typically
+ returned by the sysfs system itself if the read or store pointer
+ is ``NULL``.
+
+ ``-ENXIO``: The read or store operation failed
+
+ Error codes will not be changed without good reason, and should a change
+ to error codes result in user-space breakage, it will be fixed, or the
+ the offending change will be reverted.
+
+ Userspace applications can, however, expect the format and contents of
+ the attribute files to remain consistent in the absence of a version
+ attribute change in the context of a given attribute.
--- /dev/null
+Linux Magic System Request Key Hacks
+====================================
+
+Documentation for sysrq.c
+
+What is the magic SysRq key?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+It is a 'magical' key combo you can hit which the kernel will respond to
+regardless of whatever else it is doing, unless it is completely locked up.
+
+How do I enable the magic SysRq key?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You need to say "yes" to 'Magic SysRq key (CONFIG_MAGIC_SYSRQ)' when
+configuring the kernel. When running a kernel with SysRq compiled in,
+/proc/sys/kernel/sysrq controls the functions allowed to be invoked via
+the SysRq key. The default value in this file is set by the
+CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE config symbol, which itself defaults
+to 1. Here is the list of possible values in /proc/sys/kernel/sysrq:
+
+ - 0 - disable sysrq completely
+ - 1 - enable all functions of sysrq
+ - >1 - bitmask of allowed sysrq functions (see below for detailed function
+ description)::
+
+ 2 = 0x2 - enable control of console logging level
+ 4 = 0x4 - enable control of keyboard (SAK, unraw)
+ 8 = 0x8 - enable debugging dumps of processes etc.
+ 16 = 0x10 - enable sync command
+ 32 = 0x20 - enable remount read-only
+ 64 = 0x40 - enable signalling of processes (term, kill, oom-kill)
+ 128 = 0x80 - allow reboot/poweroff
+ 256 = 0x100 - allow nicing of all RT tasks
+
+You can set the value in the file by the following command::
+
+ echo "number" >/proc/sys/kernel/sysrq
+
+The number may be written here either as decimal or as hexadecimal
+with the 0x prefix. CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE must always be
+written in hexadecimal.
+
+Note that the value of ``/proc/sys/kernel/sysrq`` influences only the invocation
+via a keyboard. Invocation of any operation via ``/proc/sysrq-trigger`` is
+always allowed (by a user with admin privileges).
+
+How do I use the magic SysRq key?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+On x86 - You press the key combo :kbd:`ALT-SysRq-<command key>`.
+
+.. note::
+ Some
+ keyboards may not have a key labeled 'SysRq'. The 'SysRq' key is
+ also known as the 'Print Screen' key. Also some keyboards cannot
+ handle so many keys being pressed at the same time, so you might
+ have better luck with press :kbd:`Alt`, press :kbd:`SysRq`,
+ release :kbd:`SysRq`, press :kbd:`<command key>`, release everything.
+
+On SPARC - You press :kbd:`ALT-STOP-<command key>`, I believe.
+
+On the serial console (PC style standard serial ports only)
+ You send a ``BREAK``, then within 5 seconds a command key. Sending
+ ``BREAK`` twice is interpreted as a normal BREAK.
+
+On PowerPC
+ Press :kbd:`ALT - Print Screen` (or :kbd:`F13`) - :kbd:`<command key>`,
+ :kbd:`Print Screen` (or :kbd:`F13`) - :kbd:`<command key>` may suffice.
+
+On other
+ If you know of the key combos for other architectures, please
+ let me know so I can add them to this section.
+
+On all
+ write a character to /proc/sysrq-trigger. e.g.::
+
+ echo t > /proc/sysrq-trigger
+
+What are the 'command' keys?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+=========== ===================================================================
+Command Function
+=========== ===================================================================
+``b`` Will immediately reboot the system without syncing or unmounting
+ your disks.
+
+``c`` Will perform a system crash by a NULL pointer dereference.
+ A crashdump will be taken if configured.
+
+``d`` Shows all locks that are held.
+
+``e`` Send a SIGTERM to all processes, except for init.
+
+``f`` Will call the oom killer to kill a memory hog process, but do not
+ panic if nothing can be killed.
+
+``g`` Used by kgdb (kernel debugger)
+
+``h`` Will display help (actually any other key than those listed
+ here will display help. but ``h`` is easy to remember :-)
+
+``i`` Send a SIGKILL to all processes, except for init.
+
+``j`` Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl.
+
+``k`` Secure Access Key (SAK) Kills all programs on the current virtual
+ console. NOTE: See important comments below in SAK section.
+
+``l`` Shows a stack backtrace for all active CPUs.
+
+``m`` Will dump current memory info to your console.
+
+``n`` Used to make RT tasks nice-able
+
+``o`` Will shut your system off (if configured and supported).
+
+``p`` Will dump the current registers and flags to your console.
+
+``q`` Will dump per CPU lists of all armed hrtimers (but NOT regular
+ timer_list timers) and detailed information about all
+ clockevent devices.
+
+``r`` Turns off keyboard raw mode and sets it to XLATE.
+
+``s`` Will attempt to sync all mounted filesystems.
+
+``t`` Will dump a list of current tasks and their information to your
+ console.
+
+``u`` Will attempt to remount all mounted filesystems read-only.
+
+``v`` Forcefully restores framebuffer console
+``v`` Causes ETM buffer dump [ARM-specific]
+
+``w`` Dumps tasks that are in uninterruptable (blocked) state.
+
+``x`` Used by xmon interface on ppc/powerpc platforms.
+ Show global PMU Registers on sparc64.
+ Dump all TLB entries on MIPS.
+
+``y`` Show global CPU Registers [SPARC-64 specific]
+
+``z`` Dump the ftrace buffer
+
+``0``-``9`` Sets the console log level, controlling which kernel messages
+ will be printed to your console. (``0``, for example would make
+ it so that only emergency messages like PANICs or OOPSes would
+ make it to your console.)
+=========== ===================================================================
+
+Okay, so what can I use them for?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Well, unraw(r) is very handy when your X server or a svgalib program crashes.
+
+sak(k) (Secure Access Key) is useful when you want to be sure there is no
+trojan program running at console which could grab your password
+when you would try to login. It will kill all programs on given console,
+thus letting you make sure that the login prompt you see is actually
+the one from init, not some trojan program.
+
+.. important::
+
+ In its true form it is not a true SAK like the one in a
+ c2 compliant system, and it should not be mistaken as
+ such.
+
+It seems others find it useful as (System Attention Key) which is
+useful when you want to exit a program that will not let you switch consoles.
+(For example, X or a svgalib program.)
+
+``reboot(b)`` is good when you're unable to shut down. But you should also
+``sync(s)`` and ``umount(u)`` first.
+
+``crash(c)`` can be used to manually trigger a crashdump when the system is hung.
+Note that this just triggers a crash if there is no dump mechanism available.
+
+``sync(s)`` is great when your system is locked up, it allows you to sync your
+disks and will certainly lessen the chance of data loss and fscking. Note
+that the sync hasn't taken place until you see the "OK" and "Done" appear
+on the screen. (If the kernel is really in strife, you may not ever get the
+OK or Done message...)
+
+``umount(u)`` is basically useful in the same ways as ``sync(s)``. I generally
+``sync(s)``, ``umount(u)``, then ``reboot(b)`` when my system locks. It's saved
+me many a fsck. Again, the unmount (remount read-only) hasn't taken place until
+you see the "OK" and "Done" message appear on the screen.
+
+The loglevels ``0``-``9`` are useful when your console is being flooded with
+kernel messages you do not want to see. Selecting ``0`` will prevent all but
+the most urgent kernel messages from reaching your console. (They will
+still be logged if syslogd/klogd are alive, though.)
+
+``term(e)`` and ``kill(i)`` are useful if you have some sort of runaway process
+you are unable to kill any other way, especially if it's spawning other
+processes.
+
+"just thaw ``it(j)``" is useful if your system becomes unresponsive due to a
+frozen (probably root) filesystem via the FIFREEZE ioctl.
+
+Sometimes SysRq seems to get 'stuck' after using it, what can I do?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+That happens to me, also. I've found that tapping shift, alt, and control
+on both sides of the keyboard, and hitting an invalid sysrq sequence again
+will fix the problem. (i.e., something like :kbd:`alt-sysrq-z`). Switching to
+another virtual console (:kbd:`ALT+Fn`) and then back again should also help.
+
+I hit SysRq, but nothing seems to happen, what's wrong?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+There are some keyboards that produce a different keycode for SysRq than the
+pre-defined value of 99 (see ``KEY_SYSRQ`` in ``include/linux/input.h``), or
+which don't have a SysRq key at all. In these cases, run ``showkey -s`` to find
+an appropriate scancode sequence, and use ``setkeycodes <sequence> 99`` to map
+this sequence to the usual SysRq code (e.g., ``setkeycodes e05b 99``). It's
+probably best to put this command in a boot script. Oh, and by the way, you
+exit ``showkey`` by not typing anything for ten seconds.
+
+I want to add SysRQ key events to a module, how does it work?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In order to register a basic function with the table, you must first include
+the header ``include/linux/sysrq.h``, this will define everything else you need.
+Next, you must create a ``sysrq_key_op`` struct, and populate it with A) the key
+handler function you will use, B) a help_msg string, that will print when SysRQ
+prints help, and C) an action_msg string, that will print right before your
+handler is called. Your handler must conform to the prototype in 'sysrq.h'.
+
+After the ``sysrq_key_op`` is created, you can call the kernel function
+``register_sysrq_key(int key, struct sysrq_key_op *op_p);`` this will
+register the operation pointed to by ``op_p`` at table key 'key',
+if that slot in the table is blank. At module unload time, you must call
+the function ``unregister_sysrq_key(int key, struct sysrq_key_op *op_p)``, which
+will remove the key op pointed to by 'op_p' from the key 'key', if and only if
+it is currently registered in that slot. This is in case the slot has been
+overwritten since you registered it.
+
+The Magic SysRQ system works by registering key operations against a key op
+lookup table, which is defined in 'drivers/tty/sysrq.c'. This key table has
+a number of operations registered into it at compile time, but is mutable,
+and 2 functions are exported for interface to it::
+
+ register_sysrq_key and unregister_sysrq_key.
+
+Of course, never ever leave an invalid pointer in the table. I.e., when
+your module that called register_sysrq_key() exits, it must call
+unregister_sysrq_key() to clean up the sysrq key table entry that it used.
+Null pointers in the table are always safe. :)
+
+If for some reason you feel the need to call the handle_sysrq function from
+within a function called by handle_sysrq, you must be aware that you are in
+a lock (you are also in an interrupt handler, which means don't sleep!), so
+you must call ``__handle_sysrq_nolock`` instead.
+
+When I hit a SysRq key combination only the header appears on the console?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Sysrq output is subject to the same console loglevel control as all
+other console output. This means that if the kernel was booted 'quiet'
+as is common on distro kernels the output may not appear on the actual
+console, even though it will appear in the dmesg buffer, and be accessible
+via the dmesg command and to the consumers of ``/proc/kmsg``. As a specific
+exception the header line from the sysrq command is passed to all console
+consumers as if the current loglevel was maximum. If only the header
+is emitted it is almost certain that the kernel loglevel is too low.
+Should you require the output on the console channel then you will need
+to temporarily up the console loglevel using :kbd:`alt-sysrq-8` or::
+
+ echo 8 > /proc/sysrq-trigger
+
+Remember to return the loglevel to normal after triggering the sysrq
+command you are interested in.
+
+I have more questions, who can I ask?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Just ask them on the linux-kernel mailing list:
+ linux-kernel@vger.kernel.org
+
+Credits
+~~~~~~~
+
+Written by Mydraal <vulpyne@vulpyne.net>
+Updated by Adam Sulmicki <adam@cfar.umd.edu>
+Updated by Jeremy M. Dolan <jmd@turbogeek.org> 2001/01/28 10:15:59
+Added to by Crutcher Dunnavant <crutcher+kernel@datastacks.com>
--- /dev/null
+Unicode support
+===============
+
+ Last update: 2005-01-17, version 1.4
+
+This file is maintained by H. Peter Anvin <unicode@lanana.org> as part
+of the Linux Assigned Names And Numbers Authority (LANANA) project.
+The current version can be found at:
+
+ http://www.lanana.org/docs/unicode/unicode.txt
+
+Introdution
+-----------
+
+The Linux kernel code has been rewritten to use Unicode to map
+characters to fonts. By downloading a single Unicode-to-font table,
+both the eight-bit character sets and UTF-8 mode are changed to use
+the font as indicated.
+
+This changes the semantics of the eight-bit character tables subtly.
+The four character tables are now:
+
+=============== =============================== ================
+Map symbol Map name Escape code (G0)
+=============== =============================== ================
+LAT1_MAP Latin-1 (ISO 8859-1) ESC ( B
+GRAF_MAP DEC VT100 pseudographics ESC ( 0
+IBMPC_MAP IBM code page 437 ESC ( U
+USER_MAP User defined ESC ( K
+=============== =============================== ================
+
+In particular, ESC ( U is no longer "straight to font", since the font
+might be completely different than the IBM character set. This
+permits for example the use of block graphics even with a Latin-1 font
+loaded.
+
+Note that although these codes are similar to ISO 2022, neither the
+codes nor their uses match ISO 2022; Linux has two 8-bit codes (G0 and
+G1), whereas ISO 2022 has four 7-bit codes (G0-G3).
+
+In accordance with the Unicode standard/ISO 10646 the range U+F000 to
+U+F8FF has been reserved for OS-wide allocation (the Unicode Standard
+refers to this as a "Corporate Zone", since this is inaccurate for
+Linux we call it the "Linux Zone"). U+F000 was picked as the starting
+point since it lets the direct-mapping area start on a large power of
+two (in case 1024- or 2048-character fonts ever become necessary).
+This leaves U+E000 to U+EFFF as End User Zone.
+
+[v1.2]: The Unicodes range from U+F000 and up to U+F7FF have been
+hard-coded to map directly to the loaded font, bypassing the
+translation table. The user-defined map now defaults to U+F000 to
+U+F0FF, emulating the previous behaviour. In practice, this range
+might be shorter; for example, vgacon can only handle 256-character
+(U+F000..U+F0FF) or 512-character (U+F000..U+F1FF) fonts.
+
+
+Actual characters assigned in the Linux Zone
+--------------------------------------------
+
+In addition, the following characters not present in Unicode 1.1.4
+have been defined; these are used by the DEC VT graphics map. [v1.2]
+THIS USE IS OBSOLETE AND SHOULD NO LONGER BE USED; PLEASE SEE BELOW.
+
+====== ======================================
+U+F800 DEC VT GRAPHICS HORIZONTAL LINE SCAN 1
+U+F801 DEC VT GRAPHICS HORIZONTAL LINE SCAN 3
+U+F803 DEC VT GRAPHICS HORIZONTAL LINE SCAN 7
+U+F804 DEC VT GRAPHICS HORIZONTAL LINE SCAN 9
+====== ======================================
+
+The DEC VT220 uses a 6x10 character matrix, and these characters form
+a smooth progression in the DEC VT graphics character set. I have
+omitted the scan 5 line, since it is also used as a block-graphics
+character, and hence has been coded as U+2500 FORMS LIGHT HORIZONTAL.
+
+[v1.3]: These characters have been officially added to Unicode 3.2.0;
+they are added at U+23BA, U+23BB, U+23BC, U+23BD. Linux now uses the
+new values.
+
+[v1.2]: The following characters have been added to represent common
+keyboard symbols that are unlikely to ever be added to Unicode proper
+since they are horribly vendor-specific. This, of course, is an
+excellent example of horrible design.
+
+====== ======================================
+U+F810 KEYBOARD SYMBOL FLYING FLAG
+U+F811 KEYBOARD SYMBOL PULLDOWN MENU
+U+F812 KEYBOARD SYMBOL OPEN APPLE
+U+F813 KEYBOARD SYMBOL SOLID APPLE
+====== ======================================
+
+Klingon language support
+------------------------
+
+In 1996, Linux was the first operating system in the world to add
+support for the artificial language Klingon, created by Marc Okrand
+for the "Star Trek" television series. This encoding was later
+adopted by the ConScript Unicode Registry and proposed (but ultimately
+rejected) for inclusion in Unicode Plane 1. Thus, it remains as a
+Linux/CSUR private assignment in the Linux Zone.
+
+This encoding has been endorsed by the Klingon Language Institute.
+For more information, contact them at:
+
+ http://www.kli.org/
+
+Since the characters in the beginning of the Linux CZ have been more
+of the dingbats/symbols/forms type and this is a language, I have
+located it at the end, on a 16-cell boundary in keeping with standard
+Unicode practice.
+
+.. note::
+
+ This range is now officially managed by the ConScript Unicode
+ Registry. The normative reference is at:
+
+ http://www.evertype.com/standards/csur/klingon.html
+
+Klingon has an alphabet of 26 characters, a positional numeric writing
+system with 10 digits, and is written left-to-right, top-to-bottom.
+
+Several glyph forms for the Klingon alphabet have been proposed.
+However, since the set of symbols appear to be consistent throughout,
+with only the actual shapes being different, in keeping with standard
+Unicode practice these differences are considered font variants.
+
+====== =======================================================
+U+F8D0 KLINGON LETTER A
+U+F8D1 KLINGON LETTER B
+U+F8D2 KLINGON LETTER CH
+U+F8D3 KLINGON LETTER D
+U+F8D4 KLINGON LETTER E
+U+F8D5 KLINGON LETTER GH
+U+F8D6 KLINGON LETTER H
+U+F8D7 KLINGON LETTER I
+U+F8D8 KLINGON LETTER J
+U+F8D9 KLINGON LETTER L
+U+F8DA KLINGON LETTER M
+U+F8DB KLINGON LETTER N
+U+F8DC KLINGON LETTER NG
+U+F8DD KLINGON LETTER O
+U+F8DE KLINGON LETTER P
+U+F8DF KLINGON LETTER Q
+ - Written <q> in standard Okrand Latin transliteration
+U+F8E0 KLINGON LETTER QH
+ - Written <Q> in standard Okrand Latin transliteration
+U+F8E1 KLINGON LETTER R
+U+F8E2 KLINGON LETTER S
+U+F8E3 KLINGON LETTER T
+U+F8E4 KLINGON LETTER TLH
+U+F8E5 KLINGON LETTER U
+U+F8E6 KLINGON LETTER V
+U+F8E7 KLINGON LETTER W
+U+F8E8 KLINGON LETTER Y
+U+F8E9 KLINGON LETTER GLOTTAL STOP
+
+U+F8F0 KLINGON DIGIT ZERO
+U+F8F1 KLINGON DIGIT ONE
+U+F8F2 KLINGON DIGIT TWO
+U+F8F3 KLINGON DIGIT THREE
+U+F8F4 KLINGON DIGIT FOUR
+U+F8F5 KLINGON DIGIT FIVE
+U+F8F6 KLINGON DIGIT SIX
+U+F8F7 KLINGON DIGIT SEVEN
+U+F8F8 KLINGON DIGIT EIGHT
+U+F8F9 KLINGON DIGIT NINE
+
+U+F8FD KLINGON COMMA
+U+F8FE KLINGON FULL STOP
+U+F8FF KLINGON SYMBOL FOR EMPIRE
+====== =======================================================
+
+Other Fictional and Artificial Scripts
+--------------------------------------
+
+Since the assignment of the Klingon Linux Unicode block, a registry of
+fictional and artificial scripts has been established by John Cowan
+<jcowan@reutershealth.com> and Michael Everson <everson@evertype.com>.
+The ConScript Unicode Registry is accessible at:
+
+ http://www.evertype.com/standards/csur/
+
+The ranges used fall at the low end of the End User Zone and can hence
+not be normatively assigned, but it is recommended that people who
+wish to encode fictional scripts use these codes, in the interest of
+interoperability. For Klingon, CSUR has adopted the Linux encoding.
+The CSUR people are driving adding Tengwar and Cirth into Unicode
+Plane 1; the addition of Klingon to Unicode Plane 1 has been rejected
+and so the above encoding remains official.
--- /dev/null
+Software cursor for VGA
+=======================
+
+by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
+and Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+
+Linux now has some ability to manipulate cursor appearance. Normally, you
+can set the size of hardware cursor (and also work around some ugly bugs in
+those miserable Trident cards [#f1]_. You can now play a few new tricks:
+you can make your cursor look
+
+like a non-blinking red block, make it inverse background of the character it's
+over or to highlight that character and still choose whether the original
+hardware cursor should remain visible or not. There may be other things I have
+never thought of.
+
+The cursor appearance is controlled by a ``<ESC>[?1;2;3c`` escape sequence
+where 1, 2 and 3 are parameters described below. If you omit any of them,
+they will default to zeroes.
+
+first Parameter
+ specifies cursor size::
+
+ 0=default
+ 1=invisible
+ 2=underline,
+ ...
+ 8=full block
+ + 16 if you want the software cursor to be applied
+ + 32 if you want to always change the background color
+ + 64 if you dislike having the background the same as the
+ foreground.
+
+ Highlights are ignored for the last two flags.
+
+second parameter
+ selects character attribute bits you want to change
+ (by simply XORing them with the value of this parameter). On standard
+ VGA, the high four bits specify background and the low four the
+ foreground. In both groups, low three bits set color (as in normal
+ color codes used by the console) and the most significant one turns
+ on highlight (or sometimes blinking -- it depends on the configuration
+ of your VGA).
+
+third parameter
+ consists of character attribute bits you want to set.
+
+ Bit setting takes place before bit toggling, so you can simply clear a
+ bit by including it in both the set mask and the toggle mask.
+
+.. [#f1] see ``#define TRIDENT_GLITCH`` in ``drivers/video/vgacon.c``.
+
+Examples:
+=========
+
+To get normal blinking underline, use::
+
+ echo -e '\033[?2c'
+
+To get blinking block, use::
+
+ echo -e '\033[?6c'
+
+To get red non-blinking block, use::
+
+ echo -e '\033[?17;0;64c'
+++ /dev/null
-How to deal with bad memory e.g. reported by memtest86+ ?
-=========================================================
-
-March 2008
-Jan-Simon Moeller, dl9pf@gmx.de
-
-
-
-There are three possibilities I know of:
-
-1) Reinsert/swap the memory modules
-
-2) Buy new modules (best!) or try to exchange the memory
- if you have spare-parts
-
-3) Use BadRAM or memmap
-
-This Howto is about number 3) .
-
-
-BadRAM
-######
-
-BadRAM is the actively developed and available as kernel-patch
-here: http://rick.vanrein.org/linux/badram/
-
-For more details see the BadRAM documentation.
-
-memmap
-######
-
-memmap is already in the kernel and usable as kernel-parameter at
-boot-time. Its syntax is slightly strange and you may need to
-calculate the values by yourself!
-
-Syntax to exclude a memory area (see kernel-parameters.txt for details)::
-
- memmap=<size>$<address>
-
-Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
-some others. All had 0x1869xxxx in common, so I chose a pattern of
-0x18690000,0xffff0000.
-
-With the numbers of the example above::
-
- memmap=64K$0x18690000
-
-or::
-
- memmap=0x10000$0x18690000
-
+++ /dev/null
-Basic kernel profiling
-======================
-
-
-These instructions are deliberately very basic. If you want something clever,
-go read the real docs ;-)
-
-Please don't add more stuff, but feel free to
-correct my mistakes ;-) (mbligh@aracnet.com)
-
-Thanks to John Levon, Dave Hansen, et al. for help writing this.
-
-``<test>`` is the thing you're trying to measure.
-Make sure you have the correct ``System.map`` / ``vmlinux`` referenced!
-
-It is probably easiest to use ``make install`` for linux and hack
-``/sbin/installkernel`` to copy ``vmlinux`` to ``/boot``, in addition to
-``vmlinuz``, ``config``, ``System.map``, which are usually installed by default.
-
-Readprofile
------------
-
-A recent ``readprofile`` command is needed for 2.6, such as found in util-linux
-2.12a, which can be downloaded from:
-
- http://www.kernel.org/pub/linux/utils/util-linux/
-
-Most distributions will ship it already.
-
-Add ``profile=2`` to the kernel command line.
-
-Some ``readprofile`` commands::
-
- clear readprofile -r
- <test>
- dump output readprofile -m /boot/System.map > captured_profile
-
-Oprofile
---------
-
-Get the source (see Changes for required version) from
-http://oprofile.sourceforge.net/ and add ``idle=poll`` to the kernel command
-line.
-
-Configure with ``CONFIG_PROFILING=y`` and ``CONFIG_OPROFILE=y`` & reboot on new kernel::
-
- ./configure --with-kernel-support
- make install
-
-For superior results, be sure to enable the local APIC. If opreport sees
-a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
-penalty.
-
-One time setup::
-
- opcontrol --setup --vmlinux=/boot/vmlinux
-
-Some ``opcontrol`` commands::
-
- clear opcontrol --reset
- start opcontrol --start
- <test>
- stop opcontrol --stop
- dump output opreport > output_file
-
-To only report on the kernel, run ``opreport -l /boot/vmlinux > output_file``
-
-A reset is needed to clear old statistics, which survive a reboot.
-
+++ /dev/null
-Kernel Support for miscellaneous (your favourite) Binary Formats v1.1
-=====================================================================
-
-This Kernel feature allows you to invoke almost (for restrictions see below)
-every program by simply typing its name in the shell.
-This includes for example compiled Java(TM), Python or Emacs programs.
-
-To achieve this you must tell binfmt_misc which interpreter has to be invoked
-with which binary. Binfmt_misc recognises the binary-type by matching some bytes
-at the beginning of the file with a magic byte sequence (masking out specified
-bits) you have supplied. Binfmt_misc can also recognise a filename extension
-aka ``.com`` or ``.exe``.
-
-First you must mount binfmt_misc::
-
- mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
-
-To actually register a new binary type, you have to set up a string looking like
-``:name:type:offset:magic:mask:interpreter:flags`` (where you can choose the
-``:`` upon your needs) and echo it to ``/proc/sys/fs/binfmt_misc/register``.
-
-Here is what the fields mean:
-
-- ``name``
- is an identifier string. A new /proc file will be created with this
- ``name below /proc/sys/fs/binfmt_misc``; cannot contain slashes ``/`` for
- obvious reasons.
-- ``type``
- is the type of recognition. Give ``M`` for magic and ``E`` for extension.
-- ``offset``
- is the offset of the magic/mask in the file, counted in bytes. This
- defaults to 0 if you omit it (i.e. you write ``:name:type::magic...``).
- Ignored when using filename extension matching.
-- ``magic``
- is the byte sequence binfmt_misc is matching for. The magic string
- may contain hex-encoded characters like ``\x0a`` or ``\xA4``. Note that you
- must escape any NUL bytes; parsing halts at the first one. In a shell
- environment you might have to write ``\\x0a`` to prevent the shell from
- eating your ``\``.
- If you chose filename extension matching, this is the extension to be
- recognised (without the ``.``, the ``\x0a`` specials are not allowed).
- Extension matching is case sensitive, and slashes ``/`` are not allowed!
-- ``mask``
- is an (optional, defaults to all 0xff) mask. You can mask out some
- bits from matching by supplying a string like magic and as long as magic.
- The mask is anded with the byte sequence of the file. Note that you must
- escape any NUL bytes; parsing halts at the first one. Ignored when using
- filename extension matching.
-- ``interpreter``
- is the program that should be invoked with the binary as first
- argument (specify the full path)
-- ``flags``
- is an optional field that controls several aspects of the invocation
- of the interpreter. It is a string of capital letters, each controls a
- certain aspect. The following flags are supported:
-
- ``P`` - preserve-argv[0]
- Legacy behavior of binfmt_misc is to overwrite
- the original argv[0] with the full path to the binary. When this
- flag is included, binfmt_misc will add an argument to the argument
- vector for this purpose, thus preserving the original ``argv[0]``.
- e.g. If your interp is set to ``/bin/foo`` and you run ``blah``
- (which is in ``/usr/local/bin``), then the kernel will execute
- ``/bin/foo`` with ``argv[]`` set to ``["/bin/foo", "/usr/local/bin/blah", "blah"]``. The interp has to be aware of this so it can
- execute ``/usr/local/bin/blah``
- with ``argv[]`` set to ``["blah"]``.
- ``O`` - open-binary
- Legacy behavior of binfmt_misc is to pass the full path
- of the binary to the interpreter as an argument. When this flag is
- included, binfmt_misc will open the file for reading and pass its
- descriptor as an argument, instead of the full path, thus allowing
- the interpreter to execute non-readable binaries. This feature
- should be used with care - the interpreter has to be trusted not to
- emit the contents of the non-readable binary.
- ``C`` - credentials
- Currently, the behavior of binfmt_misc is to calculate
- the credentials and security token of the new process according to
- the interpreter. When this flag is included, these attributes are
- calculated according to the binary. It also implies the ``O`` flag.
- This feature should be used with care as the interpreter
- will run with root permissions when a setuid binary owned by root
- is run with binfmt_misc.
- ``F`` - fix binary
- The usual behaviour of binfmt_misc is to spawn the
- binary lazily when the misc format file is invoked. However,
- this doesn``t work very well in the face of mount namespaces and
- changeroots, so the ``F`` mode opens the binary as soon as the
- emulation is installed and uses the opened image to spawn the
- emulator, meaning it is always available once installed,
- regardless of how the environment changes.
-
-
-There are some restrictions:
-
- - the whole register string may not exceed 1920 characters
- - the magic must reside in the first 128 bytes of the file, i.e.
- offset+size(magic) has to be less than 128
- - the interpreter string may not exceed 127 characters
-
-To use binfmt_misc you have to mount it first. You can mount it with
-``mount -t binfmt_misc none /proc/sys/fs/binfmt_misc`` command, or you can add
-a line ``none /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0`` to your
-``/etc/fstab`` so it auto mounts on boot.
-
-You may want to add the binary formats in one of your ``/etc/rc`` scripts during
-boot-up. Read the manual of your init program to figure out how to do this
-right.
-
-Think about the order of adding entries! Later added entries are matched first!
-
-
-A few examples (assumed you are in ``/proc/sys/fs/binfmt_misc``):
-
-- enable support for em86 (like binfmt_em86, for Alpha AXP only)::
-
- echo ':i386:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register
- echo ':i486:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register
-
-- enable support for packed DOS applications (pre-configured dosemu hdimages)::
-
- echo ':DEXE:M::\x0eDEX::/usr/bin/dosexec:' > register
-
-- enable support for Windows executables using wine::
-
- echo ':DOSWin:M::MZ::/usr/local/bin/wine:' > register
-
-For java support see Documentation/java.txt
-
-
-You can enable/disable binfmt_misc or one binary type by echoing 0 (to disable)
-or 1 (to enable) to ``/proc/sys/fs/binfmt_misc/status`` or
-``/proc/.../the_name``.
-Catting the file tells you the current status of ``binfmt_misc/the_entry``.
-
-You can remove one entry or all entries by echoing -1 to ``/proc/.../the_name``
-or ``/proc/sys/fs/binfmt_misc/status``.
-
-
-Hints
------
-
-If you want to pass special arguments to your interpreter, you can
-write a wrapper script for it. See Documentation/java.txt for an
-example.
-
-Your interpreter should NOT look in the PATH for the filename; the kernel
-passes it the full filename (or the file descriptor) to use. Using ``$PATH`` can
-cause unexpected behaviour and can be a security hazard.
-
-
-Richard Günther <rguenth@tat.physik.uni-tuebingen.de>
+++ /dev/null
-Linux Braille Console
-=====================
-
-To get early boot messages on a braille device (before userspace screen
-readers can start), you first need to compile the support for the usual serial
-console (see :ref:`Documentation/serial-console.txt <serial_console>`), and
-for braille device
-(in :menuselection:`Device Drivers --> Accessibility support --> Console on braille device`).
-
-Then you need to specify a ``console=brl``, option on the kernel command line, the
-format is::
-
- console=brl,serial_options...
-
-where ``serial_options...`` are the same as described in
-:ref:`Documentation/serial-console.txt <serial_console>`.
-
-So for instance you can use ``console=brl,ttyS0`` if the braille device is connected to the first serial port, and ``console=brl,ttyS0,115200`` to
-override the baud rate to 115200, etc.
-
-By default, the braille device will just show the last kernel message (console
-mode). To review previous messages, press the Insert key to switch to the VT
-review mode. In review mode, the arrow keys permit to browse in the VT content,
-:kbd:`PAGE-UP`/:kbd:`PAGE-DOWN` keys go at the top/bottom of the screen, and
-the :kbd:`HOME` key goes back
-to the cursor, hence providing very basic screen reviewing facility.
-
-Sound feedback can be obtained by adding the ``braille_console.sound=1`` kernel
-parameter.
-
-For simplicity, only one braille console can be enabled, other uses of
-``console=brl,...`` will be discarded. Also note that it does not interfere with
-the console selection mechanism described in
-:ref:`Documentation/serial-console.txt <serial_console>`.
-
-For now, only the VisioBraille device is supported.
-
-Samuel Thibault <samuel.thibault@ens-lyon.org>
# (source start file, target name, title,
# author, documentclass [howto, manual, or own class]).
latex_documents = [
+ ('user/index', 'linux-user.tex', 'Linux Kernel User Documentation',
+ 'The kernel development community', 'manual'),
('kernel-documentation', 'kernel-documentation.tex', 'The Linux Kernel Documentation',
'The kernel development community', 'manual'),
('process/index', 'development-process.tex', 'Linux Kernel Development Documentation',
+++ /dev/null
-
-Linux allocated devices (4.x+ version)
-======================================
-
-This list is the Linux Device List, the official registry of allocated
-device numbers and ``/dev`` directory nodes for the Linux operating
-system.
-
-The LaTeX version of this document is no longer maintained, nor is
-the document that used to reside at lanana.org. This version in the
-mainline Linux kernel is the master document. Updates shall be sent
-as patches to the kernel maintainers (see the
-:ref:`Documentation/SubmittingPatches <submittingpatches>` document).
-Specifically explore the sections titled "CHAR and MISC DRIVERS", and
-"BLOCK LAYER" in the MAINTAINERS file to find the right maintainers
-to involve for character and block devices.
-
-This document is included by reference into the Filesystem Hierarchy
-Standard (FHS). The FHS is available from http://www.pathname.com/fhs/.
-
-Allocations marked (68k/Amiga) apply to Linux/68k on the Amiga
-platform only. Allocations marked (68k/Atari) apply to Linux/68k on
-the Atari platform only.
-
-This document is in the public domain. The authors requests, however,
-that semantically altered versions are not distributed without
-permission of the authors, assuming the authors can be contacted without
-an unreasonable effort.
-
-
-.. attention::
-
- DEVICE DRIVERS AUTHORS PLEASE READ THIS
-
- Linux now has extensive support for dynamic allocation of device numbering
- and can use ``sysfs`` and ``udev`` (``systemd``) to handle the naming needs.
- There are still some exceptions in the serial and boot device area. Before
- asking for a device number make sure you actually need one.
-
- To have a major number allocated, or a minor number in situations
- where that applies (e.g. busmice), please submit a patch and send to
- the authors as indicated above.
-
- Keep the description of the device *in the same format
- as this list*. The reason for this is that it is the only way we have
- found to ensure we have all the requisite information to publish your
- device and avoid conflicts.
-
- Finally, sometimes we have to play "namespace police." Please don't be
- offended. We often get submissions for ``/dev`` names that would be bound
- to cause conflicts down the road. We are trying to avoid getting in a
- situation where we would have to suffer an incompatible forward
- change. Therefore, please consult with us **before** you make your
- device names and numbers in any way public, at least to the point
- where it would be at all difficult to get them changed.
-
- Your cooperation is appreciated.
-
-::
-
- 0 Unnamed devices (e.g. non-device mounts)
- 0 = reserved as null device number
- See block major 144, 145, 146 for expansion areas.
-
- 1 char Memory devices
- 1 = /dev/mem Physical memory access
- 2 = /dev/kmem Kernel virtual memory access
- 3 = /dev/null Null device
- 4 = /dev/port I/O port access
- 5 = /dev/zero Null byte source
- 6 = /dev/core OBSOLETE - replaced by /proc/kcore
- 7 = /dev/full Returns ENOSPC on write
- 8 = /dev/random Nondeterministic random number gen.
- 9 = /dev/urandom Faster, less secure random number gen.
- 10 = /dev/aio Asynchronous I/O notification interface
- 11 = /dev/kmsg Writes to this come out as printk's, reads
- export the buffered printk records.
- 12 = /dev/oldmem OBSOLETE - replaced by /proc/vmcore
-
- 1 block RAM disk
- 0 = /dev/ram0 First RAM disk
- 1 = /dev/ram1 Second RAM disk
- ...
- 250 = /dev/initrd Initial RAM disk
-
- Older kernels had /dev/ramdisk (1, 1) here.
- /dev/initrd refers to a RAM disk which was preloaded
- by the boot loader; newer kernels use /dev/ram0 for
- the initrd.
-
- 2 char Pseudo-TTY masters
- 0 = /dev/ptyp0 First PTY master
- 1 = /dev/ptyp1 Second PTY master
- ...
- 255 = /dev/ptyef 256th PTY master
-
- Pseudo-tty's are named as follows:
- * Masters are "pty", slaves are "tty";
- * the fourth letter is one of pqrstuvwxyzabcde indicating
- the 1st through 16th series of 16 pseudo-ttys each, and
- * the fifth letter is one of 0123456789abcdef indicating
- the position within the series.
-
- These are the old-style (BSD) PTY devices; Unix98
- devices are on major 128 and above and use the PTY
- master multiplex (/dev/ptmx) to acquire a PTY on
- demand.
-
- 2 block Floppy disks
- 0 = /dev/fd0 Controller 0, drive 0, autodetect
- 1 = /dev/fd1 Controller 0, drive 1, autodetect
- 2 = /dev/fd2 Controller 0, drive 2, autodetect
- 3 = /dev/fd3 Controller 0, drive 3, autodetect
- 128 = /dev/fd4 Controller 1, drive 0, autodetect
- 129 = /dev/fd5 Controller 1, drive 1, autodetect
- 130 = /dev/fd6 Controller 1, drive 2, autodetect
- 131 = /dev/fd7 Controller 1, drive 3, autodetect
-
- To specify format, add to the autodetect device number:
- 0 = /dev/fd? Autodetect format
- 4 = /dev/fd?d360 5.25" 360K in a 360K drive(1)
- 20 = /dev/fd?h360 5.25" 360K in a 1200K drive(1)
- 48 = /dev/fd?h410 5.25" 410K in a 1200K drive
- 64 = /dev/fd?h420 5.25" 420K in a 1200K drive
- 24 = /dev/fd?h720 5.25" 720K in a 1200K drive
- 80 = /dev/fd?h880 5.25" 880K in a 1200K drive(1)
- 8 = /dev/fd?h1200 5.25" 1200K in a 1200K drive(1)
- 40 = /dev/fd?h1440 5.25" 1440K in a 1200K drive(1)
- 56 = /dev/fd?h1476 5.25" 1476K in a 1200K drive
- 72 = /dev/fd?h1494 5.25" 1494K in a 1200K drive
- 92 = /dev/fd?h1600 5.25" 1600K in a 1200K drive(1)
-
- 12 = /dev/fd?u360 3.5" 360K Double Density(2)
- 16 = /dev/fd?u720 3.5" 720K Double Density(1)
- 120 = /dev/fd?u800 3.5" 800K Double Density(2)
- 52 = /dev/fd?u820 3.5" 820K Double Density
- 68 = /dev/fd?u830 3.5" 830K Double Density
- 84 = /dev/fd?u1040 3.5" 1040K Double Density(1)
- 88 = /dev/fd?u1120 3.5" 1120K Double Density(1)
- 28 = /dev/fd?u1440 3.5" 1440K High Density(1)
- 124 = /dev/fd?u1600 3.5" 1600K High Density(1)
- 44 = /dev/fd?u1680 3.5" 1680K High Density(3)
- 60 = /dev/fd?u1722 3.5" 1722K High Density
- 76 = /dev/fd?u1743 3.5" 1743K High Density
- 96 = /dev/fd?u1760 3.5" 1760K High Density
- 116 = /dev/fd?u1840 3.5" 1840K High Density(3)
- 100 = /dev/fd?u1920 3.5" 1920K High Density(1)
- 32 = /dev/fd?u2880 3.5" 2880K Extra Density(1)
- 104 = /dev/fd?u3200 3.5" 3200K Extra Density
- 108 = /dev/fd?u3520 3.5" 3520K Extra Density
- 112 = /dev/fd?u3840 3.5" 3840K Extra Density(1)
-
- 36 = /dev/fd?CompaQ Compaq 2880K drive; obsolete?
-
- (1) Autodetectable format
- (2) Autodetectable format in a Double Density (720K) drive only
- (3) Autodetectable format in a High Density (1440K) drive only
-
- NOTE: The letter in the device name (d, q, h or u)
- signifies the type of drive: 5.25" Double Density (d),
- 5.25" Quad Density (q), 5.25" High Density (h) or 3.5"
- (any model, u). The use of the capital letters D, H
- and E for the 3.5" models have been deprecated, since
- the drive type is insignificant for these devices.
-
- 3 char Pseudo-TTY slaves
- 0 = /dev/ttyp0 First PTY slave
- 1 = /dev/ttyp1 Second PTY slave
- ...
- 255 = /dev/ttyef 256th PTY slave
-
- These are the old-style (BSD) PTY devices; Unix98
- devices are on major 136 and above.
-
- 3 block First MFM, RLL and IDE hard disk/CD-ROM interface
- 0 = /dev/hda Master: whole disk (or CD-ROM)
- 64 = /dev/hdb Slave: whole disk (or CD-ROM)
-
- For partitions, add to the whole disk device number:
- 0 = /dev/hd? Whole disk
- 1 = /dev/hd?1 First partition
- 2 = /dev/hd?2 Second partition
- ...
- 63 = /dev/hd?63 63rd partition
-
- For Linux/i386, partitions 1-4 are the primary
- partitions, and 5 and above are logical partitions.
- Other versions of Linux use partitioning schemes
- appropriate to their respective architectures.
-
- 4 char TTY devices
- 0 = /dev/tty0 Current virtual console
-
- 1 = /dev/tty1 First virtual console
- ...
- 63 = /dev/tty63 63rd virtual console
- 64 = /dev/ttyS0 First UART serial port
- ...
- 255 = /dev/ttyS191 192nd UART serial port
-
- UART serial ports refer to 8250/16450/16550 series devices.
-
- Older versions of the Linux kernel used this major
- number for BSD PTY devices. As of Linux 2.1.115, this
- is no longer supported. Use major numbers 2 and 3.
-
- 4 block Aliases for dynamically allocated major devices to be used
- when its not possible to create the real device nodes
- because the root filesystem is mounted read-only.
-
- 0 = /dev/root
-
- 5 char Alternate TTY devices
- 0 = /dev/tty Current TTY device
- 1 = /dev/console System console
- 2 = /dev/ptmx PTY master multiplex
- 3 = /dev/ttyprintk User messages via printk TTY device
- 64 = /dev/cua0 Callout device for ttyS0
- ...
- 255 = /dev/cua191 Callout device for ttyS191
-
- (5,1) is /dev/console starting with Linux 2.1.71. See
- the section on terminal devices for more information
- on /dev/console.
-
- 6 char Parallel printer devices
- 0 = /dev/lp0 Parallel printer on parport0
- 1 = /dev/lp1 Parallel printer on parport1
- ...
-
- Current Linux kernels no longer have a fixed mapping
- between parallel ports and I/O addresses. Instead,
- they are redirected through the parport multiplex layer.
-
- 7 char Virtual console capture devices
- 0 = /dev/vcs Current vc text contents
- 1 = /dev/vcs1 tty1 text contents
- ...
- 63 = /dev/vcs63 tty63 text contents
- 128 = /dev/vcsa Current vc text/attribute contents
- 129 = /dev/vcsa1 tty1 text/attribute contents
- ...
- 191 = /dev/vcsa63 tty63 text/attribute contents
-
- NOTE: These devices permit both read and write access.
-
- 7 block Loopback devices
- 0 = /dev/loop0 First loop device
- 1 = /dev/loop1 Second loop device
- ...
-
- The loop devices are used to mount filesystems not
- associated with block devices. The binding to the
- loop devices is handled by mount(8) or losetup(8).
-
- 8 block SCSI disk devices (0-15)
- 0 = /dev/sda First SCSI disk whole disk
- 16 = /dev/sdb Second SCSI disk whole disk
- 32 = /dev/sdc Third SCSI disk whole disk
- ...
- 240 = /dev/sdp Sixteenth SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 9 char SCSI tape devices
- 0 = /dev/st0 First SCSI tape, mode 0
- 1 = /dev/st1 Second SCSI tape, mode 0
- ...
- 32 = /dev/st0l First SCSI tape, mode 1
- 33 = /dev/st1l Second SCSI tape, mode 1
- ...
- 64 = /dev/st0m First SCSI tape, mode 2
- 65 = /dev/st1m Second SCSI tape, mode 2
- ...
- 96 = /dev/st0a First SCSI tape, mode 3
- 97 = /dev/st1a Second SCSI tape, mode 3
- ...
- 128 = /dev/nst0 First SCSI tape, mode 0, no rewind
- 129 = /dev/nst1 Second SCSI tape, mode 0, no rewind
- ...
- 160 = /dev/nst0l First SCSI tape, mode 1, no rewind
- 161 = /dev/nst1l Second SCSI tape, mode 1, no rewind
- ...
- 192 = /dev/nst0m First SCSI tape, mode 2, no rewind
- 193 = /dev/nst1m Second SCSI tape, mode 2, no rewind
- ...
- 224 = /dev/nst0a First SCSI tape, mode 3, no rewind
- 225 = /dev/nst1a Second SCSI tape, mode 3, no rewind
- ...
-
- "No rewind" refers to the omission of the default
- automatic rewind on device close. The MTREW or MTOFFL
- ioctl()'s can be used to rewind the tape regardless of
- the device used to access it.
-
- 9 block Metadisk (RAID) devices
- 0 = /dev/md0 First metadisk group
- 1 = /dev/md1 Second metadisk group
- ...
-
- The metadisk driver is used to span a
- filesystem across multiple physical disks.
-
- 10 char Non-serial mice, misc features
- 0 = /dev/logibm Logitech bus mouse
- 1 = /dev/psaux PS/2-style mouse port
- 2 = /dev/inportbm Microsoft Inport bus mouse
- 3 = /dev/atibm ATI XL bus mouse
- 4 = /dev/jbm J-mouse
- 4 = /dev/amigamouse Amiga mouse (68k/Amiga)
- 5 = /dev/atarimouse Atari mouse
- 6 = /dev/sunmouse Sun mouse
- 7 = /dev/amigamouse1 Second Amiga mouse
- 8 = /dev/smouse Simple serial mouse driver
- 9 = /dev/pc110pad IBM PC-110 digitizer pad
- 10 = /dev/adbmouse Apple Desktop Bus mouse
- 11 = /dev/vrtpanel Vr41xx embedded touch panel
- 13 = /dev/vpcmouse Connectix Virtual PC Mouse
- 14 = /dev/touchscreen/ucb1x00 UCB 1x00 touchscreen
- 15 = /dev/touchscreen/mk712 MK712 touchscreen
- 128 = /dev/beep Fancy beep device
- 129 =
- 130 = /dev/watchdog Watchdog timer port
- 131 = /dev/temperature Machine internal temperature
- 132 = /dev/hwtrap Hardware fault trap
- 133 = /dev/exttrp External device trap
- 134 = /dev/apm_bios Advanced Power Management BIOS
- 135 = /dev/rtc Real Time Clock
- 137 = /dev/vhci Bluetooth virtual HCI driver
- 139 = /dev/openprom SPARC OpenBoot PROM
- 140 = /dev/relay8 Berkshire Products Octal relay card
- 141 = /dev/relay16 Berkshire Products ISO-16 relay card
- 142 =
- 143 = /dev/pciconf PCI configuration space
- 144 = /dev/nvram Non-volatile configuration RAM
- 145 = /dev/hfmodem Soundcard shortwave modem control
- 146 = /dev/graphics Linux/SGI graphics device
- 147 = /dev/opengl Linux/SGI OpenGL pipe
- 148 = /dev/gfx Linux/SGI graphics effects device
- 149 = /dev/input/mouse Linux/SGI Irix emulation mouse
- 150 = /dev/input/keyboard Linux/SGI Irix emulation keyboard
- 151 = /dev/led Front panel LEDs
- 152 = /dev/kpoll Kernel Poll Driver
- 153 = /dev/mergemem Memory merge device
- 154 = /dev/pmu Macintosh PowerBook power manager
- 155 = /dev/isictl MultiTech ISICom serial control
- 156 = /dev/lcd Front panel LCD display
- 157 = /dev/ac Applicom Intl Profibus card
- 158 = /dev/nwbutton Netwinder external button
- 159 = /dev/nwdebug Netwinder debug interface
- 160 = /dev/nwflash Netwinder flash memory
- 161 = /dev/userdma User-space DMA access
- 162 = /dev/smbus System Management Bus
- 163 = /dev/lik Logitech Internet Keyboard
- 164 = /dev/ipmo Intel Intelligent Platform Management
- 165 = /dev/vmmon VMware virtual machine monitor
- 166 = /dev/i2o/ctl I2O configuration manager
- 167 = /dev/specialix_sxctl Specialix serial control
- 168 = /dev/tcldrv Technology Concepts serial control
- 169 = /dev/specialix_rioctl Specialix RIO serial control
- 170 = /dev/thinkpad/thinkpad IBM Thinkpad devices
- 171 = /dev/srripc QNX4 API IPC manager
- 172 = /dev/usemaclone Semaphore clone device
- 173 = /dev/ipmikcs Intelligent Platform Management
- 174 = /dev/uctrl SPARCbook 3 microcontroller
- 175 = /dev/agpgart AGP Graphics Address Remapping Table
- 176 = /dev/gtrsc Gorgy Timing radio clock
- 177 = /dev/cbm Serial CBM bus
- 178 = /dev/jsflash JavaStation OS flash SIMM
- 179 = /dev/xsvc High-speed shared-mem/semaphore service
- 180 = /dev/vrbuttons Vr41xx button input device
- 181 = /dev/toshiba Toshiba laptop SMM support
- 182 = /dev/perfctr Performance-monitoring counters
- 183 = /dev/hwrng Generic random number generator
- 184 = /dev/cpu/microcode CPU microcode update interface
- 186 = /dev/atomicps Atomic shapshot of process state data
- 187 = /dev/irnet IrNET device
- 188 = /dev/smbusbios SMBus BIOS
- 189 = /dev/ussp_ctl User space serial port control
- 190 = /dev/crash Mission Critical Linux crash dump facility
- 191 = /dev/pcl181 <information missing>
- 192 = /dev/nas_xbus NAS xbus LCD/buttons access
- 193 = /dev/d7s SPARC 7-segment display
- 194 = /dev/zkshim Zero-Knowledge network shim control
- 195 = /dev/elographics/e2201 Elographics touchscreen E271-2201
- 196 = /dev/vfio/vfio VFIO userspace driver interface
- 197 = /dev/pxa3xx-gcu PXA3xx graphics controller unit driver
- 198 = /dev/sexec Signed executable interface
- 199 = /dev/scanners/cuecat :CueCat barcode scanner
- 200 = /dev/net/tun TAP/TUN network device
- 201 = /dev/button/gulpb Transmeta GULP-B buttons
- 202 = /dev/emd/ctl Enhanced Metadisk RAID (EMD) control
- 203 = /dev/cuse Cuse (character device in user-space)
- 204 = /dev/video/em8300 EM8300 DVD decoder control
- 205 = /dev/video/em8300_mv EM8300 DVD decoder video
- 206 = /dev/video/em8300_ma EM8300 DVD decoder audio
- 207 = /dev/video/em8300_sp EM8300 DVD decoder subpicture
- 208 = /dev/compaq/cpqphpc Compaq PCI Hot Plug Controller
- 209 = /dev/compaq/cpqrid Compaq Remote Insight Driver
- 210 = /dev/impi/bt IMPI coprocessor block transfer
- 211 = /dev/impi/smic IMPI coprocessor stream interface
- 212 = /dev/watchdogs/0 First watchdog device
- 213 = /dev/watchdogs/1 Second watchdog device
- 214 = /dev/watchdogs/2 Third watchdog device
- 215 = /dev/watchdogs/3 Fourth watchdog device
- 216 = /dev/fujitsu/apanel Fujitsu/Siemens application panel
- 217 = /dev/ni/natmotn National Instruments Motion
- 218 = /dev/kchuid Inter-process chuid control
- 219 = /dev/modems/mwave MWave modem firmware upload
- 220 = /dev/mptctl Message passing technology (MPT) control
- 221 = /dev/mvista/hssdsi Montavista PICMG hot swap system driver
- 222 = /dev/mvista/hasi Montavista PICMG high availability
- 223 = /dev/input/uinput User level driver support for input
- 224 = /dev/tpm TCPA TPM driver
- 225 = /dev/pps Pulse Per Second driver
- 226 = /dev/systrace Systrace device
- 227 = /dev/mcelog X86_64 Machine Check Exception driver
- 228 = /dev/hpet HPET driver
- 229 = /dev/fuse Fuse (virtual filesystem in user-space)
- 230 = /dev/midishare MidiShare driver
- 231 = /dev/snapshot System memory snapshot device
- 232 = /dev/kvm Kernel-based virtual machine (hardware virtualization extensions)
- 233 = /dev/kmview View-OS A process with a view
- 234 = /dev/btrfs-control Btrfs control device
- 235 = /dev/autofs Autofs control device
- 236 = /dev/mapper/control Device-Mapper control device
- 237 = /dev/loop-control Loopback control device
- 238 = /dev/vhost-net Host kernel accelerator for virtio net
- 239 = /dev/uhid User-space I/O driver support for HID subsystem
-
- 240-254 Reserved for local use
- 255 Reserved for MISC_DYNAMIC_MINOR
-
- 11 char Raw keyboard device (Linux/SPARC only)
- 0 = /dev/kbd Raw keyboard device
-
- 11 char Serial Mux device (Linux/PA-RISC only)
- 0 = /dev/ttyB0 First mux port
- 1 = /dev/ttyB1 Second mux port
- ...
-
- 11 block SCSI CD-ROM devices
- 0 = /dev/scd0 First SCSI CD-ROM
- 1 = /dev/scd1 Second SCSI CD-ROM
- ...
-
- The prefix /dev/sr (instead of /dev/scd) has been deprecated.
-
- 12 char QIC-02 tape
- 2 = /dev/ntpqic11 QIC-11, no rewind-on-close
- 3 = /dev/tpqic11 QIC-11, rewind-on-close
- 4 = /dev/ntpqic24 QIC-24, no rewind-on-close
- 5 = /dev/tpqic24 QIC-24, rewind-on-close
- 6 = /dev/ntpqic120 QIC-120, no rewind-on-close
- 7 = /dev/tpqic120 QIC-120, rewind-on-close
- 8 = /dev/ntpqic150 QIC-150, no rewind-on-close
- 9 = /dev/tpqic150 QIC-150, rewind-on-close
-
- The device names specified are proposed -- if there
- are "standard" names for these devices, please let me know.
-
- 12 block
-
- 13 char Input core
- 0 = /dev/input/js0 First joystick
- 1 = /dev/input/js1 Second joystick
- ...
- 32 = /dev/input/mouse0 First mouse
- 33 = /dev/input/mouse1 Second mouse
- ...
- 63 = /dev/input/mice Unified mouse
- 64 = /dev/input/event0 First event queue
- 65 = /dev/input/event1 Second event queue
- ...
-
- Each device type has 5 bits (32 minors).
-
- 13 block Previously used for the XT disk (/dev/xdN)
- Deleted in kernel v3.9.
-
- 14 char Open Sound System (OSS)
- 0 = /dev/mixer Mixer control
- 1 = /dev/sequencer Audio sequencer
- 2 = /dev/midi00 First MIDI port
- 3 = /dev/dsp Digital audio
- 4 = /dev/audio Sun-compatible digital audio
- 6 =
- 7 = /dev/audioctl SPARC audio control device
- 8 = /dev/sequencer2 Sequencer -- alternate device
- 16 = /dev/mixer1 Second soundcard mixer control
- 17 = /dev/patmgr0 Sequencer patch manager
- 18 = /dev/midi01 Second MIDI port
- 19 = /dev/dsp1 Second soundcard digital audio
- 20 = /dev/audio1 Second soundcard Sun digital audio
- 33 = /dev/patmgr1 Sequencer patch manager
- 34 = /dev/midi02 Third MIDI port
- 50 = /dev/midi03 Fourth MIDI port
-
- 14 block
-
- 15 char Joystick
- 0 = /dev/js0 First analog joystick
- 1 = /dev/js1 Second analog joystick
- ...
- 128 = /dev/djs0 First digital joystick
- 129 = /dev/djs1 Second digital joystick
- ...
- 15 block Sony CDU-31A/CDU-33A CD-ROM
- 0 = /dev/sonycd Sony CDU-31a CD-ROM
-
- 16 char Non-SCSI scanners
- 0 = /dev/gs4500 Genius 4500 handheld scanner
-
- 16 block GoldStar CD-ROM
- 0 = /dev/gscd GoldStar CD-ROM
-
- 17 char OBSOLETE (was Chase serial card)
- 0 = /dev/ttyH0 First Chase port
- 1 = /dev/ttyH1 Second Chase port
- ...
- 17 block Optics Storage CD-ROM
- 0 = /dev/optcd Optics Storage CD-ROM
-
- 18 char OBSOLETE (was Chase serial card - alternate devices)
- 0 = /dev/cuh0 Callout device for ttyH0
- 1 = /dev/cuh1 Callout device for ttyH1
- ...
- 18 block Sanyo CD-ROM
- 0 = /dev/sjcd Sanyo CD-ROM
-
- 19 char Cyclades serial card
- 0 = /dev/ttyC0 First Cyclades port
- ...
- 31 = /dev/ttyC31 32nd Cyclades port
-
- 19 block "Double" compressed disk
- 0 = /dev/double0 First compressed disk
- ...
- 7 = /dev/double7 Eighth compressed disk
- 128 = /dev/cdouble0 Mirror of first compressed disk
- ...
- 135 = /dev/cdouble7 Mirror of eighth compressed disk
-
- See the Double documentation for the meaning of the
- mirror devices.
-
- 20 char Cyclades serial card - alternate devices
- 0 = /dev/cub0 Callout device for ttyC0
- ...
- 31 = /dev/cub31 Callout device for ttyC31
-
- 20 block Hitachi CD-ROM (under development)
- 0 = /dev/hitcd Hitachi CD-ROM
-
- 21 char Generic SCSI access
- 0 = /dev/sg0 First generic SCSI device
- 1 = /dev/sg1 Second generic SCSI device
- ...
-
- Most distributions name these /dev/sga, /dev/sgb...;
- this sets an unnecessary limit of 26 SCSI devices in
- the system and is counter to standard Linux
- device-naming practice.
-
- 21 block Acorn MFM hard drive interface
- 0 = /dev/mfma First MFM drive whole disk
- 64 = /dev/mfmb Second MFM drive whole disk
-
- This device is used on the ARM-based Acorn RiscPC.
- Partitions are handled the same way as for IDE disks
- (see major number 3).
-
- 22 char Digiboard serial card
- 0 = /dev/ttyD0 First Digiboard port
- 1 = /dev/ttyD1 Second Digiboard port
- ...
- 22 block Second IDE hard disk/CD-ROM interface
- 0 = /dev/hdc Master: whole disk (or CD-ROM)
- 64 = /dev/hdd Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 23 char Digiboard serial card - alternate devices
- 0 = /dev/cud0 Callout device for ttyD0
- 1 = /dev/cud1 Callout device for ttyD1
- ...
- 23 block Mitsumi proprietary CD-ROM
- 0 = /dev/mcd Mitsumi CD-ROM
-
- 24 char Stallion serial card
- 0 = /dev/ttyE0 Stallion port 0 card 0
- 1 = /dev/ttyE1 Stallion port 1 card 0
- ...
- 64 = /dev/ttyE64 Stallion port 0 card 1
- 65 = /dev/ttyE65 Stallion port 1 card 1
- ...
- 128 = /dev/ttyE128 Stallion port 0 card 2
- 129 = /dev/ttyE129 Stallion port 1 card 2
- ...
- 192 = /dev/ttyE192 Stallion port 0 card 3
- 193 = /dev/ttyE193 Stallion port 1 card 3
- ...
- 24 block Sony CDU-535 CD-ROM
- 0 = /dev/cdu535 Sony CDU-535 CD-ROM
-
- 25 char Stallion serial card - alternate devices
- 0 = /dev/cue0 Callout device for ttyE0
- 1 = /dev/cue1 Callout device for ttyE1
- ...
- 64 = /dev/cue64 Callout device for ttyE64
- 65 = /dev/cue65 Callout device for ttyE65
- ...
- 128 = /dev/cue128 Callout device for ttyE128
- 129 = /dev/cue129 Callout device for ttyE129
- ...
- 192 = /dev/cue192 Callout device for ttyE192
- 193 = /dev/cue193 Callout device for ttyE193
- ...
- 25 block First Matsushita (Panasonic/SoundBlaster) CD-ROM
- 0 = /dev/sbpcd0 Panasonic CD-ROM controller 0 unit 0
- 1 = /dev/sbpcd1 Panasonic CD-ROM controller 0 unit 1
- 2 = /dev/sbpcd2 Panasonic CD-ROM controller 0 unit 2
- 3 = /dev/sbpcd3 Panasonic CD-ROM controller 0 unit 3
-
- 26 char
-
- 26 block Second Matsushita (Panasonic/SoundBlaster) CD-ROM
- 0 = /dev/sbpcd4 Panasonic CD-ROM controller 1 unit 0
- 1 = /dev/sbpcd5 Panasonic CD-ROM controller 1 unit 1
- 2 = /dev/sbpcd6 Panasonic CD-ROM controller 1 unit 2
- 3 = /dev/sbpcd7 Panasonic CD-ROM controller 1 unit 3
-
- 27 char QIC-117 tape
- 0 = /dev/qft0 Unit 0, rewind-on-close
- 1 = /dev/qft1 Unit 1, rewind-on-close
- 2 = /dev/qft2 Unit 2, rewind-on-close
- 3 = /dev/qft3 Unit 3, rewind-on-close
- 4 = /dev/nqft0 Unit 0, no rewind-on-close
- 5 = /dev/nqft1 Unit 1, no rewind-on-close
- 6 = /dev/nqft2 Unit 2, no rewind-on-close
- 7 = /dev/nqft3 Unit 3, no rewind-on-close
- 16 = /dev/zqft0 Unit 0, rewind-on-close, compression
- 17 = /dev/zqft1 Unit 1, rewind-on-close, compression
- 18 = /dev/zqft2 Unit 2, rewind-on-close, compression
- 19 = /dev/zqft3 Unit 3, rewind-on-close, compression
- 20 = /dev/nzqft0 Unit 0, no rewind-on-close, compression
- 21 = /dev/nzqft1 Unit 1, no rewind-on-close, compression
- 22 = /dev/nzqft2 Unit 2, no rewind-on-close, compression
- 23 = /dev/nzqft3 Unit 3, no rewind-on-close, compression
- 32 = /dev/rawqft0 Unit 0, rewind-on-close, no file marks
- 33 = /dev/rawqft1 Unit 1, rewind-on-close, no file marks
- 34 = /dev/rawqft2 Unit 2, rewind-on-close, no file marks
- 35 = /dev/rawqft3 Unit 3, rewind-on-close, no file marks
- 36 = /dev/nrawqft0 Unit 0, no rewind-on-close, no file marks
- 37 = /dev/nrawqft1 Unit 1, no rewind-on-close, no file marks
- 38 = /dev/nrawqft2 Unit 2, no rewind-on-close, no file marks
- 39 = /dev/nrawqft3 Unit 3, no rewind-on-close, no file marks
-
- 27 block Third Matsushita (Panasonic/SoundBlaster) CD-ROM
- 0 = /dev/sbpcd8 Panasonic CD-ROM controller 2 unit 0
- 1 = /dev/sbpcd9 Panasonic CD-ROM controller 2 unit 1
- 2 = /dev/sbpcd10 Panasonic CD-ROM controller 2 unit 2
- 3 = /dev/sbpcd11 Panasonic CD-ROM controller 2 unit 3
-
- 28 char Stallion serial card - card programming
- 0 = /dev/staliomem0 First Stallion card I/O memory
- 1 = /dev/staliomem1 Second Stallion card I/O memory
- 2 = /dev/staliomem2 Third Stallion card I/O memory
- 3 = /dev/staliomem3 Fourth Stallion card I/O memory
-
- 28 char Atari SLM ACSI laser printer (68k/Atari)
- 0 = /dev/slm0 First SLM laser printer
- 1 = /dev/slm1 Second SLM laser printer
- ...
- 28 block Fourth Matsushita (Panasonic/SoundBlaster) CD-ROM
- 0 = /dev/sbpcd12 Panasonic CD-ROM controller 3 unit 0
- 1 = /dev/sbpcd13 Panasonic CD-ROM controller 3 unit 1
- 2 = /dev/sbpcd14 Panasonic CD-ROM controller 3 unit 2
- 3 = /dev/sbpcd15 Panasonic CD-ROM controller 3 unit 3
-
- 28 block ACSI disk (68k/Atari)
- 0 = /dev/ada First ACSI disk whole disk
- 16 = /dev/adb Second ACSI disk whole disk
- 32 = /dev/adc Third ACSI disk whole disk
- ...
- 240 = /dev/adp 16th ACSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15, like SCSI.
-
- 29 char Universal frame buffer
- 0 = /dev/fb0 First frame buffer
- 1 = /dev/fb1 Second frame buffer
- ...
- 31 = /dev/fb31 32nd frame buffer
-
- 29 block Aztech/Orchid/Okano/Wearnes CD-ROM
- 0 = /dev/aztcd Aztech CD-ROM
-
- 30 char iBCS-2 compatibility devices
- 0 = /dev/socksys Socket access
- 1 = /dev/spx SVR3 local X interface
- 32 = /dev/inet/ip Network access
- 33 = /dev/inet/icmp
- 34 = /dev/inet/ggp
- 35 = /dev/inet/ipip
- 36 = /dev/inet/tcp
- 37 = /dev/inet/egp
- 38 = /dev/inet/pup
- 39 = /dev/inet/udp
- 40 = /dev/inet/idp
- 41 = /dev/inet/rawip
-
- Additionally, iBCS-2 requires the following links:
-
- /dev/ip -> /dev/inet/ip
- /dev/icmp -> /dev/inet/icmp
- /dev/ggp -> /dev/inet/ggp
- /dev/ipip -> /dev/inet/ipip
- /dev/tcp -> /dev/inet/tcp
- /dev/egp -> /dev/inet/egp
- /dev/pup -> /dev/inet/pup
- /dev/udp -> /dev/inet/udp
- /dev/idp -> /dev/inet/idp
- /dev/rawip -> /dev/inet/rawip
- /dev/inet/arp -> /dev/inet/udp
- /dev/inet/rip -> /dev/inet/udp
- /dev/nfsd -> /dev/socksys
- /dev/X0R -> /dev/null (? apparently not required ?)
-
- 30 block Philips LMS CM-205 CD-ROM
- 0 = /dev/cm205cd Philips LMS CM-205 CD-ROM
-
- /dev/lmscd is an older name for this device. This
- driver does not work with the CM-205MS CD-ROM.
-
- 31 char MPU-401 MIDI
- 0 = /dev/mpu401data MPU-401 data port
- 1 = /dev/mpu401stat MPU-401 status port
-
- 31 block ROM/flash memory card
- 0 = /dev/rom0 First ROM card (rw)
- ...
- 7 = /dev/rom7 Eighth ROM card (rw)
- 8 = /dev/rrom0 First ROM card (ro)
- ...
- 15 = /dev/rrom7 Eighth ROM card (ro)
- 16 = /dev/flash0 First flash memory card (rw)
- ...
- 23 = /dev/flash7 Eighth flash memory card (rw)
- 24 = /dev/rflash0 First flash memory card (ro)
- ...
- 31 = /dev/rflash7 Eighth flash memory card (ro)
-
- The read-write (rw) devices support back-caching
- written data in RAM, as well as writing to flash RAM
- devices. The read-only devices (ro) support reading
- only.
-
- 32 char Specialix serial card
- 0 = /dev/ttyX0 First Specialix port
- 1 = /dev/ttyX1 Second Specialix port
- ...
- 32 block Philips LMS CM-206 CD-ROM
- 0 = /dev/cm206cd Philips LMS CM-206 CD-ROM
-
- 33 char Specialix serial card - alternate devices
- 0 = /dev/cux0 Callout device for ttyX0
- 1 = /dev/cux1 Callout device for ttyX1
- ...
- 33 block Third IDE hard disk/CD-ROM interface
- 0 = /dev/hde Master: whole disk (or CD-ROM)
- 64 = /dev/hdf Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 34 char Z8530 HDLC driver
- 0 = /dev/scc0 First Z8530, first port
- 1 = /dev/scc1 First Z8530, second port
- 2 = /dev/scc2 Second Z8530, first port
- 3 = /dev/scc3 Second Z8530, second port
- ...
-
- In a previous version these devices were named
- /dev/sc1 for /dev/scc0, /dev/sc2 for /dev/scc1, and so
- on.
-
- 34 block Fourth IDE hard disk/CD-ROM interface
- 0 = /dev/hdg Master: whole disk (or CD-ROM)
- 64 = /dev/hdh Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 35 char tclmidi MIDI driver
- 0 = /dev/midi0 First MIDI port, kernel timed
- 1 = /dev/midi1 Second MIDI port, kernel timed
- 2 = /dev/midi2 Third MIDI port, kernel timed
- 3 = /dev/midi3 Fourth MIDI port, kernel timed
- 64 = /dev/rmidi0 First MIDI port, untimed
- 65 = /dev/rmidi1 Second MIDI port, untimed
- 66 = /dev/rmidi2 Third MIDI port, untimed
- 67 = /dev/rmidi3 Fourth MIDI port, untimed
- 128 = /dev/smpte0 First MIDI port, SMPTE timed
- 129 = /dev/smpte1 Second MIDI port, SMPTE timed
- 130 = /dev/smpte2 Third MIDI port, SMPTE timed
- 131 = /dev/smpte3 Fourth MIDI port, SMPTE timed
-
- 35 block Slow memory ramdisk
- 0 = /dev/slram Slow memory ramdisk
-
- 36 char Netlink support
- 0 = /dev/route Routing, device updates, kernel to user
- 1 = /dev/skip enSKIP security cache control
- 3 = /dev/fwmonitor Firewall packet copies
- 16 = /dev/tap0 First Ethertap device
- ...
- 31 = /dev/tap15 16th Ethertap device
-
- 36 block OBSOLETE (was MCA ESDI hard disk)
-
- 37 char IDE tape
- 0 = /dev/ht0 First IDE tape
- 1 = /dev/ht1 Second IDE tape
- ...
- 128 = /dev/nht0 First IDE tape, no rewind-on-close
- 129 = /dev/nht1 Second IDE tape, no rewind-on-close
- ...
-
- Currently, only one IDE tape drive is supported.
-
- 37 block Zorro II ramdisk
- 0 = /dev/z2ram Zorro II ramdisk
-
- 38 char Myricom PCI Myrinet board
- 0 = /dev/mlanai0 First Myrinet board
- 1 = /dev/mlanai1 Second Myrinet board
- ...
-
- This device is used for status query, board control
- and "user level packet I/O." This board is also
- accessible as a standard networking "eth" device.
-
- 38 block OBSOLETE (was Linux/AP+)
-
- 39 char ML-16P experimental I/O board
- 0 = /dev/ml16pa-a0 First card, first analog channel
- 1 = /dev/ml16pa-a1 First card, second analog channel
- ...
- 15 = /dev/ml16pa-a15 First card, 16th analog channel
- 16 = /dev/ml16pa-d First card, digital lines
- 17 = /dev/ml16pa-c0 First card, first counter/timer
- 18 = /dev/ml16pa-c1 First card, second counter/timer
- 19 = /dev/ml16pa-c2 First card, third counter/timer
- 32 = /dev/ml16pb-a0 Second card, first analog channel
- 33 = /dev/ml16pb-a1 Second card, second analog channel
- ...
- 47 = /dev/ml16pb-a15 Second card, 16th analog channel
- 48 = /dev/ml16pb-d Second card, digital lines
- 49 = /dev/ml16pb-c0 Second card, first counter/timer
- 50 = /dev/ml16pb-c1 Second card, second counter/timer
- 51 = /dev/ml16pb-c2 Second card, third counter/timer
- ...
- 39 block
-
- 40 char
-
- 40 block
-
- 41 char Yet Another Micro Monitor
- 0 = /dev/yamm Yet Another Micro Monitor
-
- 41 block
-
- 42 char Demo/sample use
-
- 42 block Demo/sample use
-
- This number is intended for use in sample code, as
- well as a general "example" device number. It
- should never be used for a device driver that is being
- distributed; either obtain an official number or use
- the local/experimental range. The sudden addition or
- removal of a driver with this number should not cause
- ill effects to the system (bugs excepted.)
-
- IN PARTICULAR, ANY DISTRIBUTION WHICH CONTAINS A
- DEVICE DRIVER USING MAJOR NUMBER 42 IS NONCOMPLIANT.
-
- 43 char isdn4linux virtual modem
- 0 = /dev/ttyI0 First virtual modem
- ...
- 63 = /dev/ttyI63 64th virtual modem
-
- 43 block Network block devices
- 0 = /dev/nb0 First network block device
- 1 = /dev/nb1 Second network block device
- ...
-
- Network Block Device is somehow similar to loopback
- devices: If you read from it, it sends packet across
- network asking server for data. If you write to it, it
- sends packet telling server to write. It could be used
- to mounting filesystems over the net, swapping over
- the net, implementing block device in userland etc.
-
- 44 char isdn4linux virtual modem - alternate devices
- 0 = /dev/cui0 Callout device for ttyI0
- ...
- 63 = /dev/cui63 Callout device for ttyI63
-
- 44 block Flash Translation Layer (FTL) filesystems
- 0 = /dev/ftla FTL on first Memory Technology Device
- 16 = /dev/ftlb FTL on second Memory Technology Device
- 32 = /dev/ftlc FTL on third Memory Technology Device
- ...
- 240 = /dev/ftlp FTL on 16th Memory Technology Device
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the partition
- limit is 15 rather than 63 per disk (same as SCSI.)
-
- 45 char isdn4linux ISDN BRI driver
- 0 = /dev/isdn0 First virtual B channel raw data
- ...
- 63 = /dev/isdn63 64th virtual B channel raw data
- 64 = /dev/isdnctrl0 First channel control/debug
- ...
- 127 = /dev/isdnctrl63 64th channel control/debug
-
- 128 = /dev/ippp0 First SyncPPP device
- ...
- 191 = /dev/ippp63 64th SyncPPP device
-
- 255 = /dev/isdninfo ISDN monitor interface
-
- 45 block Parallel port IDE disk devices
- 0 = /dev/pda First parallel port IDE disk
- 16 = /dev/pdb Second parallel port IDE disk
- 32 = /dev/pdc Third parallel port IDE disk
- 48 = /dev/pdd Fourth parallel port IDE disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the partition
- limit is 15 rather than 63 per disk.
-
- 46 char Comtrol Rocketport serial card
- 0 = /dev/ttyR0 First Rocketport port
- 1 = /dev/ttyR1 Second Rocketport port
- ...
- 46 block Parallel port ATAPI CD-ROM devices
- 0 = /dev/pcd0 First parallel port ATAPI CD-ROM
- 1 = /dev/pcd1 Second parallel port ATAPI CD-ROM
- 2 = /dev/pcd2 Third parallel port ATAPI CD-ROM
- 3 = /dev/pcd3 Fourth parallel port ATAPI CD-ROM
-
- 47 char Comtrol Rocketport serial card - alternate devices
- 0 = /dev/cur0 Callout device for ttyR0
- 1 = /dev/cur1 Callout device for ttyR1
- ...
- 47 block Parallel port ATAPI disk devices
- 0 = /dev/pf0 First parallel port ATAPI disk
- 1 = /dev/pf1 Second parallel port ATAPI disk
- 2 = /dev/pf2 Third parallel port ATAPI disk
- 3 = /dev/pf3 Fourth parallel port ATAPI disk
-
- This driver is intended for floppy disks and similar
- devices and hence does not support partitioning.
-
- 48 char SDL RISCom serial card
- 0 = /dev/ttyL0 First RISCom port
- 1 = /dev/ttyL1 Second RISCom port
- ...
- 48 block Mylex DAC960 PCI RAID controller; first controller
- 0 = /dev/rd/c0d0 First disk, whole disk
- 8 = /dev/rd/c0d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c0d31 32nd disk, whole disk
-
- For partitions add:
- 0 = /dev/rd/c?d? Whole disk
- 1 = /dev/rd/c?d?p1 First partition
- ...
- 7 = /dev/rd/c?d?p7 Seventh partition
-
- 49 char SDL RISCom serial card - alternate devices
- 0 = /dev/cul0 Callout device for ttyL0
- 1 = /dev/cul1 Callout device for ttyL1
- ...
- 49 block Mylex DAC960 PCI RAID controller; second controller
- 0 = /dev/rd/c1d0 First disk, whole disk
- 8 = /dev/rd/c1d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c1d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 50 char Reserved for GLINT
-
- 50 block Mylex DAC960 PCI RAID controller; third controller
- 0 = /dev/rd/c2d0 First disk, whole disk
- 8 = /dev/rd/c2d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c2d31 32nd disk, whole disk
-
- 51 char Baycom radio modem OR Radio Tech BIM-XXX-RS232 radio modem
- 0 = /dev/bc0 First Baycom radio modem
- 1 = /dev/bc1 Second Baycom radio modem
- ...
- 51 block Mylex DAC960 PCI RAID controller; fourth controller
- 0 = /dev/rd/c3d0 First disk, whole disk
- 8 = /dev/rd/c3d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c3d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 52 char Spellcaster DataComm/BRI ISDN card
- 0 = /dev/dcbri0 First DataComm card
- 1 = /dev/dcbri1 Second DataComm card
- 2 = /dev/dcbri2 Third DataComm card
- 3 = /dev/dcbri3 Fourth DataComm card
-
- 52 block Mylex DAC960 PCI RAID controller; fifth controller
- 0 = /dev/rd/c4d0 First disk, whole disk
- 8 = /dev/rd/c4d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c4d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 53 char BDM interface for remote debugging MC683xx microcontrollers
- 0 = /dev/pd_bdm0 PD BDM interface on lp0
- 1 = /dev/pd_bdm1 PD BDM interface on lp1
- 2 = /dev/pd_bdm2 PD BDM interface on lp2
- 4 = /dev/icd_bdm0 ICD BDM interface on lp0
- 5 = /dev/icd_bdm1 ICD BDM interface on lp1
- 6 = /dev/icd_bdm2 ICD BDM interface on lp2
-
- This device is used for the interfacing to the MC683xx
- microcontrollers via Background Debug Mode by use of a
- Parallel Port interface. PD is the Motorola Public
- Domain Interface and ICD is the commercial interface
- by P&E.
-
- 53 block Mylex DAC960 PCI RAID controller; sixth controller
- 0 = /dev/rd/c5d0 First disk, whole disk
- 8 = /dev/rd/c5d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c5d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 54 char Electrocardiognosis Holter serial card
- 0 = /dev/holter0 First Holter port
- 1 = /dev/holter1 Second Holter port
- 2 = /dev/holter2 Third Holter port
-
- A custom serial card used by Electrocardiognosis SRL
- <mseritan@ottonel.pub.ro> to transfer data from Holter
- 24-hour heart monitoring equipment.
-
- 54 block Mylex DAC960 PCI RAID controller; seventh controller
- 0 = /dev/rd/c6d0 First disk, whole disk
- 8 = /dev/rd/c6d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c6d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 55 char DSP56001 digital signal processor
- 0 = /dev/dsp56k First DSP56001
-
- 55 block Mylex DAC960 PCI RAID controller; eighth controller
- 0 = /dev/rd/c7d0 First disk, whole disk
- 8 = /dev/rd/c7d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c7d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 56 char Apple Desktop Bus
- 0 = /dev/adb ADB bus control
-
- Additional devices will be added to this number, all
- starting with /dev/adb.
-
- 56 block Fifth IDE hard disk/CD-ROM interface
- 0 = /dev/hdi Master: whole disk (or CD-ROM)
- 64 = /dev/hdj Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 57 char Hayes ESP serial card
- 0 = /dev/ttyP0 First ESP port
- 1 = /dev/ttyP1 Second ESP port
- ...
-
- 57 block Sixth IDE hard disk/CD-ROM interface
- 0 = /dev/hdk Master: whole disk (or CD-ROM)
- 64 = /dev/hdl Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 58 char Hayes ESP serial card - alternate devices
- 0 = /dev/cup0 Callout device for ttyP0
- 1 = /dev/cup1 Callout device for ttyP1
- ...
-
- 58 block Reserved for logical volume manager
-
- 59 char sf firewall package
- 0 = /dev/firewall Communication with sf kernel module
-
- 59 block Generic PDA filesystem device
- 0 = /dev/pda0 First PDA device
- 1 = /dev/pda1 Second PDA device
- ...
-
- The pda devices are used to mount filesystems on
- remote pda's (basically slow handheld machines with
- proprietary OS's and limited memory and storage
- running small fs translation drivers) through serial /
- IRDA / parallel links.
-
- NAMING CONFLICT -- PROPOSED REVISED NAME /dev/rpda0 etc
-
- 60-63 char LOCAL/EXPERIMENTAL USE
-
- 60-63 block LOCAL/EXPERIMENTAL USE
- Allocated for local/experimental use. For devices not
- assigned official numbers, these ranges should be
- used in order to avoid conflicting with future assignments.
-
- 64 char ENskip kernel encryption package
- 0 = /dev/enskip Communication with ENskip kernel module
-
- 64 block Scramdisk/DriveCrypt encrypted devices
- 0 = /dev/scramdisk/master Master node for ioctls
- 1 = /dev/scramdisk/1 First encrypted device
- 2 = /dev/scramdisk/2 Second encrypted device
- ...
- 255 = /dev/scramdisk/255 255th encrypted device
-
- The filename of the encrypted container and the passwords
- are sent via ioctls (using the sdmount tool) to the master
- node which then activates them via one of the
- /dev/scramdisk/x nodes for loop mounting (all handled
- through the sdmount tool).
-
- Requested by: andy@scramdisklinux.org
-
- 65 char Sundance "plink" Transputer boards (obsolete, unused)
- 0 = /dev/plink0 First plink device
- 1 = /dev/plink1 Second plink device
- 2 = /dev/plink2 Third plink device
- 3 = /dev/plink3 Fourth plink device
- 64 = /dev/rplink0 First plink device, raw
- 65 = /dev/rplink1 Second plink device, raw
- 66 = /dev/rplink2 Third plink device, raw
- 67 = /dev/rplink3 Fourth plink device, raw
- 128 = /dev/plink0d First plink device, debug
- 129 = /dev/plink1d Second plink device, debug
- 130 = /dev/plink2d Third plink device, debug
- 131 = /dev/plink3d Fourth plink device, debug
- 192 = /dev/rplink0d First plink device, raw, debug
- 193 = /dev/rplink1d Second plink device, raw, debug
- 194 = /dev/rplink2d Third plink device, raw, debug
- 195 = /dev/rplink3d Fourth plink device, raw, debug
-
- This is a commercial driver; contact James Howes
- <jth@prosig.demon.co.uk> for information.
-
- 65 block SCSI disk devices (16-31)
- 0 = /dev/sdq 17th SCSI disk whole disk
- 16 = /dev/sdr 18th SCSI disk whole disk
- 32 = /dev/sds 19th SCSI disk whole disk
- ...
- 240 = /dev/sdaf 32nd SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 66 char YARC PowerPC PCI coprocessor card
- 0 = /dev/yppcpci0 First YARC card
- 1 = /dev/yppcpci1 Second YARC card
- ...
-
- 66 block SCSI disk devices (32-47)
- 0 = /dev/sdag 33th SCSI disk whole disk
- 16 = /dev/sdah 34th SCSI disk whole disk
- 32 = /dev/sdai 35th SCSI disk whole disk
- ...
- 240 = /dev/sdav 48nd SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 67 char Coda network file system
- 0 = /dev/cfs0 Coda cache manager
-
- See http://www.coda.cs.cmu.edu for information about Coda.
-
- 67 block SCSI disk devices (48-63)
- 0 = /dev/sdaw 49th SCSI disk whole disk
- 16 = /dev/sdax 50th SCSI disk whole disk
- 32 = /dev/sday 51st SCSI disk whole disk
- ...
- 240 = /dev/sdbl 64th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 68 char CAPI 2.0 interface
- 0 = /dev/capi20 Control device
- 1 = /dev/capi20.00 First CAPI 2.0 application
- 2 = /dev/capi20.01 Second CAPI 2.0 application
- ...
- 20 = /dev/capi20.19 19th CAPI 2.0 application
-
- ISDN CAPI 2.0 driver for use with CAPI 2.0
- applications; currently supports the AVM B1 card.
-
- 68 block SCSI disk devices (64-79)
- 0 = /dev/sdbm 65th SCSI disk whole disk
- 16 = /dev/sdbn 66th SCSI disk whole disk
- 32 = /dev/sdbo 67th SCSI disk whole disk
- ...
- 240 = /dev/sdcb 80th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 69 char MA16 numeric accelerator card
- 0 = /dev/ma16 Board memory access
-
- 69 block SCSI disk devices (80-95)
- 0 = /dev/sdcc 81st SCSI disk whole disk
- 16 = /dev/sdcd 82nd SCSI disk whole disk
- 32 = /dev/sdce 83th SCSI disk whole disk
- ...
- 240 = /dev/sdcr 96th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 70 char SpellCaster Protocol Services Interface
- 0 = /dev/apscfg Configuration interface
- 1 = /dev/apsauth Authentication interface
- 2 = /dev/apslog Logging interface
- 3 = /dev/apsdbg Debugging interface
- 64 = /dev/apsisdn ISDN command interface
- 65 = /dev/apsasync Async command interface
- 128 = /dev/apsmon Monitor interface
-
- 70 block SCSI disk devices (96-111)
- 0 = /dev/sdcs 97th SCSI disk whole disk
- 16 = /dev/sdct 98th SCSI disk whole disk
- 32 = /dev/sdcu 99th SCSI disk whole disk
- ...
- 240 = /dev/sddh 112nd SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 71 char Computone IntelliPort II serial card
- 0 = /dev/ttyF0 IntelliPort II board 0, port 0
- 1 = /dev/ttyF1 IntelliPort II board 0, port 1
- ...
- 63 = /dev/ttyF63 IntelliPort II board 0, port 63
- 64 = /dev/ttyF64 IntelliPort II board 1, port 0
- 65 = /dev/ttyF65 IntelliPort II board 1, port 1
- ...
- 127 = /dev/ttyF127 IntelliPort II board 1, port 63
- 128 = /dev/ttyF128 IntelliPort II board 2, port 0
- 129 = /dev/ttyF129 IntelliPort II board 2, port 1
- ...
- 191 = /dev/ttyF191 IntelliPort II board 2, port 63
- 192 = /dev/ttyF192 IntelliPort II board 3, port 0
- 193 = /dev/ttyF193 IntelliPort II board 3, port 1
- ...
- 255 = /dev/ttyF255 IntelliPort II board 3, port 63
-
- 71 block SCSI disk devices (112-127)
- 0 = /dev/sddi 113th SCSI disk whole disk
- 16 = /dev/sddj 114th SCSI disk whole disk
- 32 = /dev/sddk 115th SCSI disk whole disk
- ...
- 240 = /dev/sddx 128th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 72 char Computone IntelliPort II serial card - alternate devices
- 0 = /dev/cuf0 Callout device for ttyF0
- 1 = /dev/cuf1 Callout device for ttyF1
- ...
- 63 = /dev/cuf63 Callout device for ttyF63
- 64 = /dev/cuf64 Callout device for ttyF64
- 65 = /dev/cuf65 Callout device for ttyF65
- ...
- 127 = /dev/cuf127 Callout device for ttyF127
- 128 = /dev/cuf128 Callout device for ttyF128
- 129 = /dev/cuf129 Callout device for ttyF129
- ...
- 191 = /dev/cuf191 Callout device for ttyF191
- 192 = /dev/cuf192 Callout device for ttyF192
- 193 = /dev/cuf193 Callout device for ttyF193
- ...
- 255 = /dev/cuf255 Callout device for ttyF255
-
- 72 block Compaq Intelligent Drive Array, first controller
- 0 = /dev/ida/c0d0 First logical drive whole disk
- 16 = /dev/ida/c0d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c0d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 73 char Computone IntelliPort II serial card - control devices
- 0 = /dev/ip2ipl0 Loadware device for board 0
- 1 = /dev/ip2stat0 Status device for board 0
- 4 = /dev/ip2ipl1 Loadware device for board 1
- 5 = /dev/ip2stat1 Status device for board 1
- 8 = /dev/ip2ipl2 Loadware device for board 2
- 9 = /dev/ip2stat2 Status device for board 2
- 12 = /dev/ip2ipl3 Loadware device for board 3
- 13 = /dev/ip2stat3 Status device for board 3
-
- 73 block Compaq Intelligent Drive Array, second controller
- 0 = /dev/ida/c1d0 First logical drive whole disk
- 16 = /dev/ida/c1d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c1d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 74 char SCI bridge
- 0 = /dev/SCI/0 SCI device 0
- 1 = /dev/SCI/1 SCI device 1
- ...
-
- Currently for Dolphin Interconnect Solutions' PCI-SCI
- bridge.
-
- 74 block Compaq Intelligent Drive Array, third controller
- 0 = /dev/ida/c2d0 First logical drive whole disk
- 16 = /dev/ida/c2d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c2d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 75 char Specialix IO8+ serial card
- 0 = /dev/ttyW0 First IO8+ port, first card
- 1 = /dev/ttyW1 Second IO8+ port, first card
- ...
- 8 = /dev/ttyW8 First IO8+ port, second card
- ...
-
- 75 block Compaq Intelligent Drive Array, fourth controller
- 0 = /dev/ida/c3d0 First logical drive whole disk
- 16 = /dev/ida/c3d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c3d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 76 char Specialix IO8+ serial card - alternate devices
- 0 = /dev/cuw0 Callout device for ttyW0
- 1 = /dev/cuw1 Callout device for ttyW1
- ...
- 8 = /dev/cuw8 Callout device for ttyW8
- ...
-
- 76 block Compaq Intelligent Drive Array, fifth controller
- 0 = /dev/ida/c4d0 First logical drive whole disk
- 16 = /dev/ida/c4d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c4d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
-
- 77 char ComScire Quantum Noise Generator
- 0 = /dev/qng ComScire Quantum Noise Generator
-
- 77 block Compaq Intelligent Drive Array, sixth controller
- 0 = /dev/ida/c5d0 First logical drive whole disk
- 16 = /dev/ida/c5d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c5d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 78 char PAM Software's multimodem boards
- 0 = /dev/ttyM0 First PAM modem
- 1 = /dev/ttyM1 Second PAM modem
- ...
-
- 78 block Compaq Intelligent Drive Array, seventh controller
- 0 = /dev/ida/c6d0 First logical drive whole disk
- 16 = /dev/ida/c6d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c6d15 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 79 char PAM Software's multimodem boards - alternate devices
- 0 = /dev/cum0 Callout device for ttyM0
- 1 = /dev/cum1 Callout device for ttyM1
- ...
-
- 79 block Compaq Intelligent Drive Array, eighth controller
- 0 = /dev/ida/c7d0 First logical drive whole disk
- 16 = /dev/ida/c7d1 Second logical drive whole disk
- ...
- 240 = /dev/ida/c715 16th logical drive whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 80 char Photometrics AT200 CCD camera
- 0 = /dev/at200 Photometrics AT200 CCD camera
-
- 80 block I2O hard disk
- 0 = /dev/i2o/hda First I2O hard disk, whole disk
- 16 = /dev/i2o/hdb Second I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdp 16th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 81 char video4linux
- 0 = /dev/video0 Video capture/overlay device
- ...
- 63 = /dev/video63 Video capture/overlay device
- 64 = /dev/radio0 Radio device
- ...
- 127 = /dev/radio63 Radio device
- 128 = /dev/swradio0 Software Defined Radio device
- ...
- 191 = /dev/swradio63 Software Defined Radio device
- 224 = /dev/vbi0 Vertical blank interrupt
- ...
- 255 = /dev/vbi31 Vertical blank interrupt
-
- Minor numbers are allocated dynamically unless
- CONFIG_VIDEO_FIXED_MINOR_RANGES (default n)
- configuration option is set.
-
- 81 block I2O hard disk
- 0 = /dev/i2o/hdq 17th I2O hard disk, whole disk
- 16 = /dev/i2o/hdr 18th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdaf 32nd I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 82 char WiNRADiO communications receiver card
- 0 = /dev/winradio0 First WiNRADiO card
- 1 = /dev/winradio1 Second WiNRADiO card
- ...
-
- The driver and documentation may be obtained from
- http://www.winradio.com/
-
- 82 block I2O hard disk
- 0 = /dev/i2o/hdag 33rd I2O hard disk, whole disk
- 16 = /dev/i2o/hdah 34th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdav 48th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 83 char Matrox mga_vid video driver
- 0 = /dev/mga_vid0 1st video card
- 1 = /dev/mga_vid1 2nd video card
- 2 = /dev/mga_vid2 3rd video card
- ...
- 15 = /dev/mga_vid15 16th video card
-
- 83 block I2O hard disk
- 0 = /dev/i2o/hdaw 49th I2O hard disk, whole disk
- 16 = /dev/i2o/hdax 50th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdbl 64th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 84 char Ikon 1011[57] Versatec Greensheet Interface
- 0 = /dev/ihcp0 First Greensheet port
- 1 = /dev/ihcp1 Second Greensheet port
-
- 84 block I2O hard disk
- 0 = /dev/i2o/hdbm 65th I2O hard disk, whole disk
- 16 = /dev/i2o/hdbn 66th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdcb 80th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 85 char Linux/SGI shared memory input queue
- 0 = /dev/shmiq Master shared input queue
- 1 = /dev/qcntl0 First device pushed
- 2 = /dev/qcntl1 Second device pushed
- ...
-
- 85 block I2O hard disk
- 0 = /dev/i2o/hdcc 81st I2O hard disk, whole disk
- 16 = /dev/i2o/hdcd 82nd I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hdcr 96th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 86 char SCSI media changer
- 0 = /dev/sch0 First SCSI media changer
- 1 = /dev/sch1 Second SCSI media changer
- ...
-
- 86 block I2O hard disk
- 0 = /dev/i2o/hdcs 97th I2O hard disk, whole disk
- 16 = /dev/i2o/hdct 98th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hddh 112th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 87 char Sony Control-A1 stereo control bus
- 0 = /dev/controla0 First device on chain
- 1 = /dev/controla1 Second device on chain
- ...
-
- 87 block I2O hard disk
- 0 = /dev/i2o/hddi 113rd I2O hard disk, whole disk
- 16 = /dev/i2o/hddj 114th I2O hard disk, whole disk
- ...
- 240 = /dev/i2o/hddx 128th I2O hard disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 88 char COMX synchronous serial card
- 0 = /dev/comx0 COMX channel 0
- 1 = /dev/comx1 COMX channel 1
- ...
-
- 88 block Seventh IDE hard disk/CD-ROM interface
- 0 = /dev/hdm Master: whole disk (or CD-ROM)
- 64 = /dev/hdn Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 89 char I2C bus interface
- 0 = /dev/i2c-0 First I2C adapter
- 1 = /dev/i2c-1 Second I2C adapter
- ...
-
- 89 block Eighth IDE hard disk/CD-ROM interface
- 0 = /dev/hdo Master: whole disk (or CD-ROM)
- 64 = /dev/hdp Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 90 char Memory Technology Device (RAM, ROM, Flash)
- 0 = /dev/mtd0 First MTD (rw)
- 1 = /dev/mtdr0 First MTD (ro)
- ...
- 30 = /dev/mtd15 16th MTD (rw)
- 31 = /dev/mtdr15 16th MTD (ro)
-
- 90 block Ninth IDE hard disk/CD-ROM interface
- 0 = /dev/hdq Master: whole disk (or CD-ROM)
- 64 = /dev/hdr Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 91 char CAN-Bus devices
- 0 = /dev/can0 First CAN-Bus controller
- 1 = /dev/can1 Second CAN-Bus controller
- ...
-
- 91 block Tenth IDE hard disk/CD-ROM interface
- 0 = /dev/hds Master: whole disk (or CD-ROM)
- 64 = /dev/hdt Slave: whole disk (or CD-ROM)
-
- Partitions are handled the same way as for the first
- interface (see major number 3).
-
- 92 char Reserved for ith Kommunikationstechnik MIC ISDN card
-
- 92 block PPDD encrypted disk driver
- 0 = /dev/ppdd0 First encrypted disk
- 1 = /dev/ppdd1 Second encrypted disk
- ...
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 93 char
-
- 93 block NAND Flash Translation Layer filesystem
- 0 = /dev/nftla First NFTL layer
- 16 = /dev/nftlb Second NFTL layer
- ...
- 240 = /dev/nftlp 16th NTFL layer
-
- 94 char
-
- 94 block IBM S/390 DASD block storage
- 0 = /dev/dasda First DASD device, major
- 1 = /dev/dasda1 First DASD device, block 1
- 2 = /dev/dasda2 First DASD device, block 2
- 3 = /dev/dasda3 First DASD device, block 3
- 4 = /dev/dasdb Second DASD device, major
- 5 = /dev/dasdb1 Second DASD device, block 1
- 6 = /dev/dasdb2 Second DASD device, block 2
- 7 = /dev/dasdb3 Second DASD device, block 3
- ...
-
- 95 char IP filter
- 0 = /dev/ipl Filter control device/log file
- 1 = /dev/ipnat NAT control device/log file
- 2 = /dev/ipstate State information log file
- 3 = /dev/ipauth Authentication control device/log file
- ...
-
- 96 char Parallel port ATAPI tape devices
- 0 = /dev/pt0 First parallel port ATAPI tape
- 1 = /dev/pt1 Second parallel port ATAPI tape
- ...
- 128 = /dev/npt0 First p.p. ATAPI tape, no rewind
- 129 = /dev/npt1 Second p.p. ATAPI tape, no rewind
- ...
-
- 96 block Inverse NAND Flash Translation Layer
- 0 = /dev/inftla First INFTL layer
- 16 = /dev/inftlb Second INFTL layer
- ...
- 240 = /dev/inftlp 16th INTFL layer
-
- 97 char Parallel port generic ATAPI interface
- 0 = /dev/pg0 First parallel port ATAPI device
- 1 = /dev/pg1 Second parallel port ATAPI device
- 2 = /dev/pg2 Third parallel port ATAPI device
- 3 = /dev/pg3 Fourth parallel port ATAPI device
-
- These devices support the same API as the generic SCSI
- devices.
-
- 98 char Control and Measurement Device (comedi)
- 0 = /dev/comedi0 First comedi device
- 1 = /dev/comedi1 Second comedi device
- ...
-
- See http://stm.lbl.gov/comedi.
-
- 98 block User-mode virtual block device
- 0 = /dev/ubda First user-mode block device
- 16 = /dev/udbb Second user-mode block device
- ...
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- This device is used by the user-mode virtual kernel port.
-
- 99 char Raw parallel ports
- 0 = /dev/parport0 First parallel port
- 1 = /dev/parport1 Second parallel port
- ...
-
- 99 block JavaStation flash disk
- 0 = /dev/jsfd JavaStation flash disk
-
- 100 char Telephony for Linux
- 0 = /dev/phone0 First telephony device
- 1 = /dev/phone1 Second telephony device
- ...
-
- 101 char Motorola DSP 56xxx board
- 0 = /dev/mdspstat Status information
- 1 = /dev/mdsp1 First DSP board I/O controls
- ...
- 16 = /dev/mdsp16 16th DSP board I/O controls
-
- 101 block AMI HyperDisk RAID controller
- 0 = /dev/amiraid/ar0 First array whole disk
- 16 = /dev/amiraid/ar1 Second array whole disk
- ...
- 240 = /dev/amiraid/ar15 16th array whole disk
-
- For each device, partitions are added as:
- 0 = /dev/amiraid/ar? Whole disk
- 1 = /dev/amiraid/ar?p1 First partition
- 2 = /dev/amiraid/ar?p2 Second partition
- ...
- 15 = /dev/amiraid/ar?p15 15th partition
-
- 102 char
-
- 102 block Compressed block device
- 0 = /dev/cbd/a First compressed block device, whole device
- 16 = /dev/cbd/b Second compressed block device, whole device
- ...
- 240 = /dev/cbd/p 16th compressed block device, whole device
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 103 char Arla network file system
- 0 = /dev/nnpfs0 First NNPFS device
- 1 = /dev/nnpfs1 Second NNPFS device
-
- Arla is a free clone of the Andrew File System, AFS.
- The NNPFS device gives user mode filesystem
- implementations a kernel presence for caching and easy
- mounting. For more information about the project,
- write to <arla-drinkers@stacken.kth.se> or see
- http://www.stacken.kth.se/project/arla/
-
- 103 block Audit device
- 0 = /dev/audit Audit device
-
- 104 char Flash BIOS support
-
- 104 block Compaq Next Generation Drive Array, first controller
- 0 = /dev/cciss/c0d0 First logical drive, whole disk
- 16 = /dev/cciss/c0d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c0d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 105 char Comtrol VS-1000 serial controller
- 0 = /dev/ttyV0 First VS-1000 port
- 1 = /dev/ttyV1 Second VS-1000 port
- ...
-
- 105 block Compaq Next Generation Drive Array, second controller
- 0 = /dev/cciss/c1d0 First logical drive, whole disk
- 16 = /dev/cciss/c1d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c1d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 106 char Comtrol VS-1000 serial controller - alternate devices
- 0 = /dev/cuv0 First VS-1000 port
- 1 = /dev/cuv1 Second VS-1000 port
- ...
-
- 106 block Compaq Next Generation Drive Array, third controller
- 0 = /dev/cciss/c2d0 First logical drive, whole disk
- 16 = /dev/cciss/c2d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c2d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 107 char 3Dfx Voodoo Graphics device
- 0 = /dev/3dfx Primary 3Dfx graphics device
-
- 107 block Compaq Next Generation Drive Array, fourth controller
- 0 = /dev/cciss/c3d0 First logical drive, whole disk
- 16 = /dev/cciss/c3d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c3d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 108 char Device independent PPP interface
- 0 = /dev/ppp Device independent PPP interface
-
- 108 block Compaq Next Generation Drive Array, fifth controller
- 0 = /dev/cciss/c4d0 First logical drive, whole disk
- 16 = /dev/cciss/c4d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c4d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 109 char Reserved for logical volume manager
-
- 109 block Compaq Next Generation Drive Array, sixth controller
- 0 = /dev/cciss/c5d0 First logical drive, whole disk
- 16 = /dev/cciss/c5d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c5d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 110 char miroMEDIA Surround board
- 0 = /dev/srnd0 First miroMEDIA Surround board
- 1 = /dev/srnd1 Second miroMEDIA Surround board
- ...
-
- 110 block Compaq Next Generation Drive Array, seventh controller
- 0 = /dev/cciss/c6d0 First logical drive, whole disk
- 16 = /dev/cciss/c6d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c6d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 111 char
-
- 111 block Compaq Next Generation Drive Array, eighth controller
- 0 = /dev/cciss/c7d0 First logical drive, whole disk
- 16 = /dev/cciss/c7d1 Second logical drive, whole disk
- ...
- 240 = /dev/cciss/c7d15 16th logical drive, whole disk
-
- Partitions are handled the same way as for Mylex
- DAC960 (see major number 48) except that the limit on
- partitions is 15.
-
- 112 char ISI serial card
- 0 = /dev/ttyM0 First ISI port
- 1 = /dev/ttyM1 Second ISI port
- ...
-
- There is currently a device-naming conflict between
- these and PAM multimodems (major 78).
-
- 112 block IBM iSeries virtual disk
- 0 = /dev/iseries/vda First virtual disk, whole disk
- 8 = /dev/iseries/vdb Second virtual disk, whole disk
- ...
- 200 = /dev/iseries/vdz 26th virtual disk, whole disk
- 208 = /dev/iseries/vdaa 27th virtual disk, whole disk
- ...
- 248 = /dev/iseries/vdaf 32nd virtual disk, whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 7.
-
- 113 char ISI serial card - alternate devices
- 0 = /dev/cum0 Callout device for ttyM0
- 1 = /dev/cum1 Callout device for ttyM1
- ...
-
- 113 block IBM iSeries virtual CD-ROM
- 0 = /dev/iseries/vcda First virtual CD-ROM
- 1 = /dev/iseries/vcdb Second virtual CD-ROM
- ...
-
- 114 char Picture Elements ISE board
- 0 = /dev/ise0 First ISE board
- 1 = /dev/ise1 Second ISE board
- ...
- 128 = /dev/isex0 Control node for first ISE board
- 129 = /dev/isex1 Control node for second ISE board
- ...
-
- The ISE board is an embedded computer, optimized for
- image processing. The /dev/iseN nodes are the general
- I/O access to the board, the /dev/isex0 nodes command
- nodes used to control the board.
-
- 114 block IDE BIOS powered software RAID interfaces such as the
- Promise Fastrak
-
- 0 = /dev/ataraid/d0
- 1 = /dev/ataraid/d0p1
- 2 = /dev/ataraid/d0p2
- ...
- 16 = /dev/ataraid/d1
- 17 = /dev/ataraid/d1p1
- 18 = /dev/ataraid/d1p2
- ...
- 255 = /dev/ataraid/d15p15
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 115 char TI link cable devices (115 was formerly the console driver speaker)
- 0 = /dev/tipar0 Parallel cable on first parallel port
- ...
- 7 = /dev/tipar7 Parallel cable on seventh parallel port
-
- 8 = /dev/tiser0 Serial cable on first serial port
- ...
- 15 = /dev/tiser7 Serial cable on seventh serial port
-
- 16 = /dev/tiusb0 First USB cable
- ...
- 47 = /dev/tiusb31 32nd USB cable
-
- 115 block NetWare (NWFS) Devices (0-255)
-
- The NWFS (NetWare) devices are used to present a
- collection of NetWare Mirror Groups or NetWare
- Partitions as a logical storage segment for
- use in mounting NetWare volumes. A maximum of
- 256 NetWare volumes can be supported in a single
- machine.
-
- http://cgfa.telepac.pt/ftp2/kernel.org/linux/kernel/people/jmerkey/nwfs/
-
- 0 = /dev/nwfs/v0 First NetWare (NWFS) Logical Volume
- 1 = /dev/nwfs/v1 Second NetWare (NWFS) Logical Volume
- 2 = /dev/nwfs/v2 Third NetWare (NWFS) Logical Volume
- ...
- 255 = /dev/nwfs/v255 Last NetWare (NWFS) Logical Volume
-
- 116 char Advanced Linux Sound Driver (ALSA)
-
- 116 block MicroMemory battery backed RAM adapter (NVRAM)
- Supports 16 boards, 15 partitions each.
- Requested by neilb at cse.unsw.edu.au.
-
- 0 = /dev/umem/d0 Whole of first board
- 1 = /dev/umem/d0p1 First partition of first board
- 2 = /dev/umem/d0p2 Second partition of first board
- 15 = /dev/umem/d0p15 15th partition of first board
-
- 16 = /dev/umem/d1 Whole of second board
- 17 = /dev/umem/d1p1 First partition of second board
- ...
- 255= /dev/umem/d15p15 15th partition of 16th board.
-
- 117 char COSA/SRP synchronous serial card
- 0 = /dev/cosa0c0 1st board, 1st channel
- 1 = /dev/cosa0c1 1st board, 2nd channel
- ...
- 16 = /dev/cosa1c0 2nd board, 1st channel
- 17 = /dev/cosa1c1 2nd board, 2nd channel
- ...
-
- 117 block Enterprise Volume Management System (EVMS)
-
- The EVMS driver uses a layered, plug-in model to provide
- unparalleled flexibility and extensibility in managing
- storage. This allows for easy expansion or customization
- of various levels of volume management. Requested by
- Mark Peloquin (peloquin at us.ibm.com).
-
- Note: EVMS populates and manages all the devnodes in
- /dev/evms.
-
- http://sf.net/projects/evms
-
- 0 = /dev/evms/block_device EVMS block device
- 1 = /dev/evms/legacyname1 First EVMS legacy device
- 2 = /dev/evms/legacyname2 Second EVMS legacy device
- ...
- Both ranges can grow (down or up) until they meet.
- ...
- 254 = /dev/evms/EVMSname2 Second EVMS native device
- 255 = /dev/evms/EVMSname1 First EVMS native device
-
- Note: legacyname(s) are derived from the normal legacy
- device names. For example, /dev/hda5 would become
- /dev/evms/hda5.
-
- 118 char IBM Cryptographic Accelerator
- 0 = /dev/ica Virtual interface to all IBM Crypto Accelerators
- 1 = /dev/ica0 IBMCA Device 0
- 2 = /dev/ica1 IBMCA Device 1
- ...
-
- 119 char VMware virtual network control
- 0 = /dev/vnet0 1st virtual network
- 1 = /dev/vnet1 2nd virtual network
- ...
-
- 120-127 char LOCAL/EXPERIMENTAL USE
-
- 120-127 block LOCAL/EXPERIMENTAL USE
- Allocated for local/experimental use. For devices not
- assigned official numbers, these ranges should be
- used in order to avoid conflicting with future assignments.
-
- 128-135 char Unix98 PTY masters
-
- These devices should not have corresponding device
- nodes; instead they should be accessed through the
- /dev/ptmx cloning interface.
-
- 128 block SCSI disk devices (128-143)
- 0 = /dev/sddy 129th SCSI disk whole disk
- 16 = /dev/sddz 130th SCSI disk whole disk
- 32 = /dev/sdea 131th SCSI disk whole disk
- ...
- 240 = /dev/sden 144th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 129 block SCSI disk devices (144-159)
- 0 = /dev/sdeo 145th SCSI disk whole disk
- 16 = /dev/sdep 146th SCSI disk whole disk
- 32 = /dev/sdeq 147th SCSI disk whole disk
- ...
- 240 = /dev/sdfd 160th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 130 char (Misc devices)
-
- 130 block SCSI disk devices (160-175)
- 0 = /dev/sdfe 161st SCSI disk whole disk
- 16 = /dev/sdff 162nd SCSI disk whole disk
- 32 = /dev/sdfg 163rd SCSI disk whole disk
- ...
- 240 = /dev/sdft 176th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 131 block SCSI disk devices (176-191)
- 0 = /dev/sdfu 177th SCSI disk whole disk
- 16 = /dev/sdfv 178th SCSI disk whole disk
- 32 = /dev/sdfw 179th SCSI disk whole disk
- ...
- 240 = /dev/sdgj 192nd SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 132 block SCSI disk devices (192-207)
- 0 = /dev/sdgk 193rd SCSI disk whole disk
- 16 = /dev/sdgl 194th SCSI disk whole disk
- 32 = /dev/sdgm 195th SCSI disk whole disk
- ...
- 240 = /dev/sdgz 208th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 133 block SCSI disk devices (208-223)
- 0 = /dev/sdha 209th SCSI disk whole disk
- 16 = /dev/sdhb 210th SCSI disk whole disk
- 32 = /dev/sdhc 211th SCSI disk whole disk
- ...
- 240 = /dev/sdhp 224th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 134 block SCSI disk devices (224-239)
- 0 = /dev/sdhq 225th SCSI disk whole disk
- 16 = /dev/sdhr 226th SCSI disk whole disk
- 32 = /dev/sdhs 227th SCSI disk whole disk
- ...
- 240 = /dev/sdif 240th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 135 block SCSI disk devices (240-255)
- 0 = /dev/sdig 241st SCSI disk whole disk
- 16 = /dev/sdih 242nd SCSI disk whole disk
- 32 = /dev/sdih 243rd SCSI disk whole disk
- ...
- 240 = /dev/sdiv 256th SCSI disk whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 136-143 char Unix98 PTY slaves
- 0 = /dev/pts/0 First Unix98 pseudo-TTY
- 1 = /dev/pts/1 Second Unix98 pseudo-TTY
- ...
-
- These device nodes are automatically generated with
- the proper permissions and modes by mounting the
- devpts filesystem onto /dev/pts with the appropriate
- mount options (distribution dependent, however, on
- *most* distributions the appropriate options are
- "mode=0620,gid=<gid of the "tty" group>".)
-
- 136 block Mylex DAC960 PCI RAID controller; ninth controller
- 0 = /dev/rd/c8d0 First disk, whole disk
- 8 = /dev/rd/c8d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c8d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 137 block Mylex DAC960 PCI RAID controller; tenth controller
- 0 = /dev/rd/c9d0 First disk, whole disk
- 8 = /dev/rd/c9d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c9d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 138 block Mylex DAC960 PCI RAID controller; eleventh controller
- 0 = /dev/rd/c10d0 First disk, whole disk
- 8 = /dev/rd/c10d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c10d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 139 block Mylex DAC960 PCI RAID controller; twelfth controller
- 0 = /dev/rd/c11d0 First disk, whole disk
- 8 = /dev/rd/c11d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c11d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 140 block Mylex DAC960 PCI RAID controller; thirteenth controller
- 0 = /dev/rd/c12d0 First disk, whole disk
- 8 = /dev/rd/c12d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c12d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 141 block Mylex DAC960 PCI RAID controller; fourteenth controller
- 0 = /dev/rd/c13d0 First disk, whole disk
- 8 = /dev/rd/c13d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c13d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 142 block Mylex DAC960 PCI RAID controller; fifteenth controller
- 0 = /dev/rd/c14d0 First disk, whole disk
- 8 = /dev/rd/c14d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c14d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 143 block Mylex DAC960 PCI RAID controller; sixteenth controller
- 0 = /dev/rd/c15d0 First disk, whole disk
- 8 = /dev/rd/c15d1 Second disk, whole disk
- ...
- 248 = /dev/rd/c15d31 32nd disk, whole disk
-
- Partitions are handled as for major 48.
-
- 144 char Encapsulated PPP
- 0 = /dev/pppox0 First PPP over Ethernet
- ...
- 63 = /dev/pppox63 64th PPP over Ethernet
-
- This is primarily used for ADSL.
-
- The SST 5136-DN DeviceNet interface driver has been
- relocated to major 183 due to an unfortunate conflict.
-
- 144 block Expansion Area #1 for more non-device (e.g. NFS) mounts
- 0 = mounted device 256
- 255 = mounted device 511
-
- 145 char SAM9407-based soundcard
- 0 = /dev/sam0_mixer
- 1 = /dev/sam0_sequencer
- 2 = /dev/sam0_midi00
- 3 = /dev/sam0_dsp
- 4 = /dev/sam0_audio
- 6 = /dev/sam0_sndstat
- 18 = /dev/sam0_midi01
- 34 = /dev/sam0_midi02
- 50 = /dev/sam0_midi03
- 64 = /dev/sam1_mixer
- ...
- 128 = /dev/sam2_mixer
- ...
- 192 = /dev/sam3_mixer
- ...
-
- Device functions match OSS, but offer a number of
- addons, which are sam9407 specific. OSS can be
- operated simultaneously, taking care of the codec.
-
- 145 block Expansion Area #2 for more non-device (e.g. NFS) mounts
- 0 = mounted device 512
- 255 = mounted device 767
-
- 146 char SYSTRAM SCRAMNet mirrored-memory network
- 0 = /dev/scramnet0 First SCRAMNet device
- 1 = /dev/scramnet1 Second SCRAMNet device
- ...
-
- 146 block Expansion Area #3 for more non-device (e.g. NFS) mounts
- 0 = mounted device 768
- 255 = mounted device 1023
-
- 147 char Aureal Semiconductor Vortex Audio device
- 0 = /dev/aureal0 First Aureal Vortex
- 1 = /dev/aureal1 Second Aureal Vortex
- ...
-
- 147 block Distributed Replicated Block Device (DRBD)
- 0 = /dev/drbd0 First DRBD device
- 1 = /dev/drbd1 Second DRBD device
- ...
-
- 148 char Technology Concepts serial card
- 0 = /dev/ttyT0 First TCL port
- 1 = /dev/ttyT1 Second TCL port
- ...
-
- 149 char Technology Concepts serial card - alternate devices
- 0 = /dev/cut0 Callout device for ttyT0
- 1 = /dev/cut0 Callout device for ttyT1
- ...
-
- 150 char Real-Time Linux FIFOs
- 0 = /dev/rtf0 First RTLinux FIFO
- 1 = /dev/rtf1 Second RTLinux FIFO
- ...
-
- 151 char DPT I2O SmartRaid V controller
- 0 = /dev/dpti0 First DPT I2O adapter
- 1 = /dev/dpti1 Second DPT I2O adapter
- ...
-
- 152 char EtherDrive Control Device
- 0 = /dev/etherd/ctl Connect/Disconnect an EtherDrive
- 1 = /dev/etherd/err Monitor errors
- 2 = /dev/etherd/raw Raw AoE packet monitor
-
- 152 block EtherDrive Block Devices
- 0 = /dev/etherd/0 EtherDrive 0
- ...
- 255 = /dev/etherd/255 EtherDrive 255
-
- 153 char SPI Bus Interface (sometimes referred to as MicroWire)
- 0 = /dev/spi0 First SPI device on the bus
- 1 = /dev/spi1 Second SPI device on the bus
- ...
- 15 = /dev/spi15 Sixteenth SPI device on the bus
-
- 153 block Enhanced Metadisk RAID (EMD) storage units
- 0 = /dev/emd/0 First unit
- 1 = /dev/emd/0p1 Partition 1 on First unit
- 2 = /dev/emd/0p2 Partition 2 on First unit
- ...
- 15 = /dev/emd/0p15 Partition 15 on First unit
-
- 16 = /dev/emd/1 Second unit
- 32 = /dev/emd/2 Third unit
- ...
- 240 = /dev/emd/15 Sixteenth unit
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 154 char Specialix RIO serial card
- 0 = /dev/ttySR0 First RIO port
- ...
- 255 = /dev/ttySR255 256th RIO port
-
- 155 char Specialix RIO serial card - alternate devices
- 0 = /dev/cusr0 Callout device for ttySR0
- ...
- 255 = /dev/cusr255 Callout device for ttySR255
-
- 156 char Specialix RIO serial card
- 0 = /dev/ttySR256 257th RIO port
- ...
- 255 = /dev/ttySR511 512th RIO port
-
- 157 char Specialix RIO serial card - alternate devices
- 0 = /dev/cusr256 Callout device for ttySR256
- ...
- 255 = /dev/cusr511 Callout device for ttySR511
-
- 158 char Dialogic GammaLink fax driver
- 0 = /dev/gfax0 GammaLink channel 0
- 1 = /dev/gfax1 GammaLink channel 1
- ...
-
- 159 char RESERVED
-
- 159 block RESERVED
-
- 160 char General Purpose Instrument Bus (GPIB)
- 0 = /dev/gpib0 First GPIB bus
- 1 = /dev/gpib1 Second GPIB bus
- ...
-
- 160 block Carmel 8-port SATA Disks on First Controller
- 0 = /dev/carmel/0 SATA disk 0 whole disk
- 1 = /dev/carmel/0p1 SATA disk 0 partition 1
- ...
- 31 = /dev/carmel/0p31 SATA disk 0 partition 31
-
- 32 = /dev/carmel/1 SATA disk 1 whole disk
- 64 = /dev/carmel/2 SATA disk 2 whole disk
- ...
- 224 = /dev/carmel/7 SATA disk 7 whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 31.
-
- 161 char IrCOMM devices (IrDA serial/parallel emulation)
- 0 = /dev/ircomm0 First IrCOMM device
- 1 = /dev/ircomm1 Second IrCOMM device
- ...
- 16 = /dev/irlpt0 First IrLPT device
- 17 = /dev/irlpt1 Second IrLPT device
- ...
-
- 161 block Carmel 8-port SATA Disks on Second Controller
- 0 = /dev/carmel/8 SATA disk 8 whole disk
- 1 = /dev/carmel/8p1 SATA disk 8 partition 1
- ...
- 31 = /dev/carmel/8p31 SATA disk 8 partition 31
-
- 32 = /dev/carmel/9 SATA disk 9 whole disk
- 64 = /dev/carmel/10 SATA disk 10 whole disk
- ...
- 224 = /dev/carmel/15 SATA disk 15 whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 31.
-
- 162 char Raw block device interface
- 0 = /dev/rawctl Raw I/O control device
- 1 = /dev/raw/raw1 First raw I/O device
- 2 = /dev/raw/raw2 Second raw I/O device
- ...
- max minor number of raw device is set by kernel config
- MAX_RAW_DEVS or raw module parameter 'max_raw_devs'
-
- 163 char
-
- 164 char Chase Research AT/PCI-Fast serial card
- 0 = /dev/ttyCH0 AT/PCI-Fast board 0, port 0
- ...
- 15 = /dev/ttyCH15 AT/PCI-Fast board 0, port 15
- 16 = /dev/ttyCH16 AT/PCI-Fast board 1, port 0
- ...
- 31 = /dev/ttyCH31 AT/PCI-Fast board 1, port 15
- 32 = /dev/ttyCH32 AT/PCI-Fast board 2, port 0
- ...
- 47 = /dev/ttyCH47 AT/PCI-Fast board 2, port 15
- 48 = /dev/ttyCH48 AT/PCI-Fast board 3, port 0
- ...
- 63 = /dev/ttyCH63 AT/PCI-Fast board 3, port 15
-
- 165 char Chase Research AT/PCI-Fast serial card - alternate devices
- 0 = /dev/cuch0 Callout device for ttyCH0
- ...
- 63 = /dev/cuch63 Callout device for ttyCH63
-
- 166 char ACM USB modems
- 0 = /dev/ttyACM0 First ACM modem
- 1 = /dev/ttyACM1 Second ACM modem
- ...
-
- 167 char ACM USB modems - alternate devices
- 0 = /dev/cuacm0 Callout device for ttyACM0
- 1 = /dev/cuacm1 Callout device for ttyACM1
- ...
-
- 168 char Eracom CSA7000 PCI encryption adaptor
- 0 = /dev/ecsa0 First CSA7000
- 1 = /dev/ecsa1 Second CSA7000
- ...
-
- 169 char Eracom CSA8000 PCI encryption adaptor
- 0 = /dev/ecsa8-0 First CSA8000
- 1 = /dev/ecsa8-1 Second CSA8000
- ...
-
- 170 char AMI MegaRAC remote access controller
- 0 = /dev/megarac0 First MegaRAC card
- 1 = /dev/megarac1 Second MegaRAC card
- ...
-
- 171 char Reserved for IEEE 1394 (Firewire)
-
- 172 char Moxa Intellio serial card
- 0 = /dev/ttyMX0 First Moxa port
- 1 = /dev/ttyMX1 Second Moxa port
- ...
- 127 = /dev/ttyMX127 128th Moxa port
- 128 = /dev/moxactl Moxa control port
-
- 173 char Moxa Intellio serial card - alternate devices
- 0 = /dev/cumx0 Callout device for ttyMX0
- 1 = /dev/cumx1 Callout device for ttyMX1
- ...
- 127 = /dev/cumx127 Callout device for ttyMX127
-
- 174 char SmartIO serial card
- 0 = /dev/ttySI0 First SmartIO port
- 1 = /dev/ttySI1 Second SmartIO port
- ...
-
- 175 char SmartIO serial card - alternate devices
- 0 = /dev/cusi0 Callout device for ttySI0
- 1 = /dev/cusi1 Callout device for ttySI1
- ...
-
- 176 char nCipher nFast PCI crypto accelerator
- 0 = /dev/nfastpci0 First nFast PCI device
- 1 = /dev/nfastpci1 First nFast PCI device
- ...
-
- 177 char TI PCILynx memory spaces
- 0 = /dev/pcilynx/aux0 AUX space of first PCILynx card
- ...
- 15 = /dev/pcilynx/aux15 AUX space of 16th PCILynx card
- 16 = /dev/pcilynx/rom0 ROM space of first PCILynx card
- ...
- 31 = /dev/pcilynx/rom15 ROM space of 16th PCILynx card
- 32 = /dev/pcilynx/ram0 RAM space of first PCILynx card
- ...
- 47 = /dev/pcilynx/ram15 RAM space of 16th PCILynx card
-
- 178 char Giganet cLAN1xxx virtual interface adapter
- 0 = /dev/clanvi0 First cLAN adapter
- 1 = /dev/clanvi1 Second cLAN adapter
- ...
-
- 179 block MMC block devices
- 0 = /dev/mmcblk0 First SD/MMC card
- 1 = /dev/mmcblk0p1 First partition on first MMC card
- 8 = /dev/mmcblk1 Second SD/MMC card
- ...
-
- The start of next SD/MMC card can be configured with
- CONFIG_MMC_BLOCK_MINORS, or overridden at boot/modprobe
- time using the mmcblk.perdev_minors option. That would
- bump the offset between each card to be the configured
- value instead of the default 8.
-
- 179 char CCube DVXChip-based PCI products
- 0 = /dev/dvxirq0 First DVX device
- 1 = /dev/dvxirq1 Second DVX device
- ...
-
- 180 char USB devices
- 0 = /dev/usb/lp0 First USB printer
- ...
- 15 = /dev/usb/lp15 16th USB printer
- 48 = /dev/usb/scanner0 First USB scanner
- ...
- 63 = /dev/usb/scanner15 16th USB scanner
- 64 = /dev/usb/rio500 Diamond Rio 500
- 65 = /dev/usb/usblcd USBLCD Interface (info@usblcd.de)
- 66 = /dev/usb/cpad0 Synaptics cPad (mouse/LCD)
- 96 = /dev/usb/hiddev0 1st USB HID device
- ...
- 111 = /dev/usb/hiddev15 16th USB HID device
- 112 = /dev/usb/auer0 1st auerswald ISDN device
- ...
- 127 = /dev/usb/auer15 16th auerswald ISDN device
- 128 = /dev/usb/brlvgr0 First Braille Voyager device
- ...
- 131 = /dev/usb/brlvgr3 Fourth Braille Voyager device
- 132 = /dev/usb/idmouse ID Mouse (fingerprint scanner) device
- 133 = /dev/usb/sisusbvga1 First SiSUSB VGA device
- ...
- 140 = /dev/usb/sisusbvga8 Eighth SISUSB VGA device
- 144 = /dev/usb/lcd USB LCD device
- 160 = /dev/usb/legousbtower0 1st USB Legotower device
- ...
- 175 = /dev/usb/legousbtower15 16th USB Legotower device
- 176 = /dev/usb/usbtmc1 First USB TMC device
- ...
- 191 = /dev/usb/usbtmc16 16th USB TMC device
- 192 = /dev/usb/yurex1 First USB Yurex device
- ...
- 209 = /dev/usb/yurex16 16th USB Yurex device
-
- 180 block USB block devices
- 0 = /dev/uba First USB block device
- 8 = /dev/ubb Second USB block device
- 16 = /dev/ubc Third USB block device
- ...
-
- 181 char Conrad Electronic parallel port radio clocks
- 0 = /dev/pcfclock0 First Conrad radio clock
- 1 = /dev/pcfclock1 Second Conrad radio clock
- ...
-
- 182 char Picture Elements THR2 binarizer
- 0 = /dev/pethr0 First THR2 board
- 1 = /dev/pethr1 Second THR2 board
- ...
-
- 183 char SST 5136-DN DeviceNet interface
- 0 = /dev/ss5136dn0 First DeviceNet interface
- 1 = /dev/ss5136dn1 Second DeviceNet interface
- ...
-
- This device used to be assigned to major number 144.
- It had to be moved due to an unfortunate conflict.
-
- 184 char Picture Elements' video simulator/sender
- 0 = /dev/pevss0 First sender board
- 1 = /dev/pevss1 Second sender board
- ...
-
- 185 char InterMezzo high availability file system
- 0 = /dev/intermezzo0 First cache manager
- 1 = /dev/intermezzo1 Second cache manager
- ...
-
- See http://web.archive.org/web/20080115195241/
- http://inter-mezzo.org/index.html
-
- 186 char Object-based storage control device
- 0 = /dev/obd0 First obd control device
- 1 = /dev/obd1 Second obd control device
- ...
-
- See ftp://ftp.lustre.org/pub/obd for code and information.
-
- 187 char DESkey hardware encryption device
- 0 = /dev/deskey0 First DES key
- 1 = /dev/deskey1 Second DES key
- ...
-
- 188 char USB serial converters
- 0 = /dev/ttyUSB0 First USB serial converter
- 1 = /dev/ttyUSB1 Second USB serial converter
- ...
-
- 189 char USB serial converters - alternate devices
- 0 = /dev/cuusb0 Callout device for ttyUSB0
- 1 = /dev/cuusb1 Callout device for ttyUSB1
- ...
-
- 190 char Kansas City tracker/tuner card
- 0 = /dev/kctt0 First KCT/T card
- 1 = /dev/kctt1 Second KCT/T card
- ...
-
- 191 char Reserved for PCMCIA
-
- 192 char Kernel profiling interface
- 0 = /dev/profile Profiling control device
- 1 = /dev/profile0 Profiling device for CPU 0
- 2 = /dev/profile1 Profiling device for CPU 1
- ...
-
- 193 char Kernel event-tracing interface
- 0 = /dev/trace Tracing control device
- 1 = /dev/trace0 Tracing device for CPU 0
- 2 = /dev/trace1 Tracing device for CPU 1
- ...
-
- 194 char linVideoStreams (LINVS)
- 0 = /dev/mvideo/status0 Video compression status
- 1 = /dev/mvideo/stream0 Video stream
- 2 = /dev/mvideo/frame0 Single compressed frame
- 3 = /dev/mvideo/rawframe0 Raw uncompressed frame
- 4 = /dev/mvideo/codec0 Direct codec access
- 5 = /dev/mvideo/video4linux0 Video4Linux compatibility
-
- 16 = /dev/mvideo/status1 Second device
- ...
- 32 = /dev/mvideo/status2 Third device
- ...
- ...
- 240 = /dev/mvideo/status15 16th device
- ...
-
- 195 char Nvidia graphics devices
- 0 = /dev/nvidia0 First Nvidia card
- 1 = /dev/nvidia1 Second Nvidia card
- ...
- 255 = /dev/nvidiactl Nvidia card control device
-
- 196 char Tormenta T1 card
- 0 = /dev/tor/0 Master control channel for all cards
- 1 = /dev/tor/1 First DS0
- 2 = /dev/tor/2 Second DS0
- ...
- 48 = /dev/tor/48 48th DS0
- 49 = /dev/tor/49 First pseudo-channel
- 50 = /dev/tor/50 Second pseudo-channel
- ...
-
- 197 char OpenTNF tracing facility
- 0 = /dev/tnf/t0 Trace 0 data extraction
- 1 = /dev/tnf/t1 Trace 1 data extraction
- ...
- 128 = /dev/tnf/status Tracing facility status
- 130 = /dev/tnf/trace Tracing device
-
- 198 char Total Impact TPMP2 quad coprocessor PCI card
- 0 = /dev/tpmp2/0 First card
- 1 = /dev/tpmp2/1 Second card
- ...
-
- 199 char Veritas volume manager (VxVM) volumes
- 0 = /dev/vx/rdsk/*/* First volume
- 1 = /dev/vx/rdsk/*/* Second volume
- ...
-
- 199 block Veritas volume manager (VxVM) volumes
- 0 = /dev/vx/dsk/*/* First volume
- 1 = /dev/vx/dsk/*/* Second volume
- ...
-
- The namespace in these directories is maintained by
- the user space VxVM software.
-
- 200 char Veritas VxVM configuration interface
- 0 = /dev/vx/config Configuration access node
- 1 = /dev/vx/trace Volume i/o trace access node
- 2 = /dev/vx/iod Volume i/o daemon access node
- 3 = /dev/vx/info Volume information access node
- 4 = /dev/vx/task Volume tasks access node
- 5 = /dev/vx/taskmon Volume tasks monitor daemon
-
- 201 char Veritas VxVM dynamic multipathing driver
- 0 = /dev/vx/rdmp/* First multipath device
- 1 = /dev/vx/rdmp/* Second multipath device
- ...
- 201 block Veritas VxVM dynamic multipathing driver
- 0 = /dev/vx/dmp/* First multipath device
- 1 = /dev/vx/dmp/* Second multipath device
- ...
-
- The namespace in these directories is maintained by
- the user space VxVM software.
-
- 202 char CPU model-specific registers
- 0 = /dev/cpu/0/msr MSRs on CPU 0
- 1 = /dev/cpu/1/msr MSRs on CPU 1
- ...
-
- 202 block Xen Virtual Block Device
- 0 = /dev/xvda First Xen VBD whole disk
- 16 = /dev/xvdb Second Xen VBD whole disk
- 32 = /dev/xvdc Third Xen VBD whole disk
- ...
- 240 = /dev/xvdp Sixteenth Xen VBD whole disk
-
- Partitions are handled in the same way as for IDE
- disks (see major number 3) except that the limit on
- partitions is 15.
-
- 203 char CPU CPUID information
- 0 = /dev/cpu/0/cpuid CPUID on CPU 0
- 1 = /dev/cpu/1/cpuid CPUID on CPU 1
- ...
-
- 204 char Low-density serial ports
- 0 = /dev/ttyLU0 LinkUp Systems L72xx UART - port 0
- 1 = /dev/ttyLU1 LinkUp Systems L72xx UART - port 1
- 2 = /dev/ttyLU2 LinkUp Systems L72xx UART - port 2
- 3 = /dev/ttyLU3 LinkUp Systems L72xx UART - port 3
- 4 = /dev/ttyFB0 Intel Footbridge (ARM)
- 5 = /dev/ttySA0 StrongARM builtin serial port 0
- 6 = /dev/ttySA1 StrongARM builtin serial port 1
- 7 = /dev/ttySA2 StrongARM builtin serial port 2
- 8 = /dev/ttySC0 SCI serial port (SuperH) - port 0
- 9 = /dev/ttySC1 SCI serial port (SuperH) - port 1
- 10 = /dev/ttySC2 SCI serial port (SuperH) - port 2
- 11 = /dev/ttySC3 SCI serial port (SuperH) - port 3
- 12 = /dev/ttyFW0 Firmware console - port 0
- 13 = /dev/ttyFW1 Firmware console - port 1
- 14 = /dev/ttyFW2 Firmware console - port 2
- 15 = /dev/ttyFW3 Firmware console - port 3
- 16 = /dev/ttyAM0 ARM "AMBA" serial port 0
- ...
- 31 = /dev/ttyAM15 ARM "AMBA" serial port 15
- 32 = /dev/ttyDB0 DataBooster serial port 0
- ...
- 39 = /dev/ttyDB7 DataBooster serial port 7
- 40 = /dev/ttySG0 SGI Altix console port
- 41 = /dev/ttySMX0 Motorola i.MX - port 0
- 42 = /dev/ttySMX1 Motorola i.MX - port 1
- 43 = /dev/ttySMX2 Motorola i.MX - port 2
- 44 = /dev/ttyMM0 Marvell MPSC - port 0
- 45 = /dev/ttyMM1 Marvell MPSC - port 1
- 46 = /dev/ttyCPM0 PPC CPM (SCC or SMC) - port 0
- ...
- 47 = /dev/ttyCPM5 PPC CPM (SCC or SMC) - port 5
- 50 = /dev/ttyIOC0 Altix serial card
- ...
- 81 = /dev/ttyIOC31 Altix serial card
- 82 = /dev/ttyVR0 NEC VR4100 series SIU
- 83 = /dev/ttyVR1 NEC VR4100 series DSIU
- 84 = /dev/ttyIOC84 Altix ioc4 serial card
- ...
- 115 = /dev/ttyIOC115 Altix ioc4 serial card
- 116 = /dev/ttySIOC0 Altix ioc3 serial card
- ...
- 147 = /dev/ttySIOC31 Altix ioc3 serial card
- 148 = /dev/ttyPSC0 PPC PSC - port 0
- ...
- 153 = /dev/ttyPSC5 PPC PSC - port 5
- 154 = /dev/ttyAT0 ATMEL serial port 0
- ...
- 169 = /dev/ttyAT15 ATMEL serial port 15
- 170 = /dev/ttyNX0 Hilscher netX serial port 0
- ...
- 185 = /dev/ttyNX15 Hilscher netX serial port 15
- 186 = /dev/ttyJ0 JTAG1 DCC protocol based serial port emulation
- 187 = /dev/ttyUL0 Xilinx uartlite - port 0
- ...
- 190 = /dev/ttyUL3 Xilinx uartlite - port 3
- 191 = /dev/xvc0 Xen virtual console - port 0
- 192 = /dev/ttyPZ0 pmac_zilog - port 0
- ...
- 195 = /dev/ttyPZ3 pmac_zilog - port 3
- 196 = /dev/ttyTX0 TX39/49 serial port 0
- ...
- 204 = /dev/ttyTX7 TX39/49 serial port 7
- 205 = /dev/ttySC0 SC26xx serial port 0
- 206 = /dev/ttySC1 SC26xx serial port 1
- 207 = /dev/ttySC2 SC26xx serial port 2
- 208 = /dev/ttySC3 SC26xx serial port 3
- 209 = /dev/ttyMAX0 MAX3100 serial port 0
- 210 = /dev/ttyMAX1 MAX3100 serial port 1
- 211 = /dev/ttyMAX2 MAX3100 serial port 2
- 212 = /dev/ttyMAX3 MAX3100 serial port 3
-
- 205 char Low-density serial ports (alternate device)
- 0 = /dev/culu0 Callout device for ttyLU0
- 1 = /dev/culu1 Callout device for ttyLU1
- 2 = /dev/culu2 Callout device for ttyLU2
- 3 = /dev/culu3 Callout device for ttyLU3
- 4 = /dev/cufb0 Callout device for ttyFB0
- 5 = /dev/cusa0 Callout device for ttySA0
- 6 = /dev/cusa1 Callout device for ttySA1
- 7 = /dev/cusa2 Callout device for ttySA2
- 8 = /dev/cusc0 Callout device for ttySC0
- 9 = /dev/cusc1 Callout device for ttySC1
- 10 = /dev/cusc2 Callout device for ttySC2
- 11 = /dev/cusc3 Callout device for ttySC3
- 12 = /dev/cufw0 Callout device for ttyFW0
- 13 = /dev/cufw1 Callout device for ttyFW1
- 14 = /dev/cufw2 Callout device for ttyFW2
- 15 = /dev/cufw3 Callout device for ttyFW3
- 16 = /dev/cuam0 Callout device for ttyAM0
- ...
- 31 = /dev/cuam15 Callout device for ttyAM15
- 32 = /dev/cudb0 Callout device for ttyDB0
- ...
- 39 = /dev/cudb7 Callout device for ttyDB7
- 40 = /dev/cusg0 Callout device for ttySG0
- 41 = /dev/ttycusmx0 Callout device for ttySMX0
- 42 = /dev/ttycusmx1 Callout device for ttySMX1
- 43 = /dev/ttycusmx2 Callout device for ttySMX2
- 46 = /dev/cucpm0 Callout device for ttyCPM0
- ...
- 49 = /dev/cucpm5 Callout device for ttyCPM5
- 50 = /dev/cuioc40 Callout device for ttyIOC40
- ...
- 81 = /dev/cuioc431 Callout device for ttyIOC431
- 82 = /dev/cuvr0 Callout device for ttyVR0
- 83 = /dev/cuvr1 Callout device for ttyVR1
-
- 206 char OnStream SC-x0 tape devices
- 0 = /dev/osst0 First OnStream SCSI tape, mode 0
- 1 = /dev/osst1 Second OnStream SCSI tape, mode 0
- ...
- 32 = /dev/osst0l First OnStream SCSI tape, mode 1
- 33 = /dev/osst1l Second OnStream SCSI tape, mode 1
- ...
- 64 = /dev/osst0m First OnStream SCSI tape, mode 2
- 65 = /dev/osst1m Second OnStream SCSI tape, mode 2
- ...
- 96 = /dev/osst0a First OnStream SCSI tape, mode 3
- 97 = /dev/osst1a Second OnStream SCSI tape, mode 3
- ...
- 128 = /dev/nosst0 No rewind version of /dev/osst0
- 129 = /dev/nosst1 No rewind version of /dev/osst1
- ...
- 160 = /dev/nosst0l No rewind version of /dev/osst0l
- 161 = /dev/nosst1l No rewind version of /dev/osst1l
- ...
- 192 = /dev/nosst0m No rewind version of /dev/osst0m
- 193 = /dev/nosst1m No rewind version of /dev/osst1m
- ...
- 224 = /dev/nosst0a No rewind version of /dev/osst0a
- 225 = /dev/nosst1a No rewind version of /dev/osst1a
- ...
-
- The OnStream SC-x0 SCSI tapes do not support the
- standard SCSI SASD command set and therefore need
- their own driver "osst". Note that the IDE, USB (and
- maybe ParPort) versions may be driven via ide-scsi or
- usb-storage SCSI emulation and this osst device and
- driver as well. The ADR-x0 drives are QIC-157
- compliant and don't need osst.
-
- 207 char Compaq ProLiant health feature indicate
- 0 = /dev/cpqhealth/cpqw Redirector interface
- 1 = /dev/cpqhealth/crom EISA CROM
- 2 = /dev/cpqhealth/cdt Data Table
- 3 = /dev/cpqhealth/cevt Event Log
- 4 = /dev/cpqhealth/casr Automatic Server Recovery
- 5 = /dev/cpqhealth/cecc ECC Memory
- 6 = /dev/cpqhealth/cmca Machine Check Architecture
- 7 = /dev/cpqhealth/ccsm Deprecated CDT
- 8 = /dev/cpqhealth/cnmi NMI Handling
- 9 = /dev/cpqhealth/css Sideshow Management
- 10 = /dev/cpqhealth/cram CMOS interface
- 11 = /dev/cpqhealth/cpci PCI IRQ interface
-
- 208 char User space serial ports
- 0 = /dev/ttyU0 First user space serial port
- 1 = /dev/ttyU1 Second user space serial port
- ...
-
- 209 char User space serial ports (alternate devices)
- 0 = /dev/cuu0 Callout device for ttyU0
- 1 = /dev/cuu1 Callout device for ttyU1
- ...
-
- 210 char SBE, Inc. sync/async serial card
- 0 = /dev/sbei/wxcfg0 Configuration device for board 0
- 1 = /dev/sbei/dld0 Download device for board 0
- 2 = /dev/sbei/wan00 WAN device, port 0, board 0
- 3 = /dev/sbei/wan01 WAN device, port 1, board 0
- 4 = /dev/sbei/wan02 WAN device, port 2, board 0
- 5 = /dev/sbei/wan03 WAN device, port 3, board 0
- 6 = /dev/sbei/wanc00 WAN clone device, port 0, board 0
- 7 = /dev/sbei/wanc01 WAN clone device, port 1, board 0
- 8 = /dev/sbei/wanc02 WAN clone device, port 2, board 0
- 9 = /dev/sbei/wanc03 WAN clone device, port 3, board 0
- 10 = /dev/sbei/wxcfg1 Configuration device for board 1
- 11 = /dev/sbei/dld1 Download device for board 1
- 12 = /dev/sbei/wan10 WAN device, port 0, board 1
- 13 = /dev/sbei/wan11 WAN device, port 1, board 1
- 14 = /dev/sbei/wan12 WAN device, port 2, board 1
- 15 = /dev/sbei/wan13 WAN device, port 3, board 1
- 16 = /dev/sbei/wanc10 WAN clone device, port 0, board 1
- 17 = /dev/sbei/wanc11 WAN clone device, port 1, board 1
- 18 = /dev/sbei/wanc12 WAN clone device, port 2, board 1
- 19 = /dev/sbei/wanc13 WAN clone device, port 3, board 1
- ...
-
- Yes, each board is really spaced 10 (decimal) apart.
-
- 211 char Addinum CPCI1500 digital I/O card
- 0 = /dev/addinum/cpci1500/0 First CPCI1500 card
- 1 = /dev/addinum/cpci1500/1 Second CPCI1500 card
- ...
-
- 212 char LinuxTV.org DVB driver subsystem
- 0 = /dev/dvb/adapter0/video0 first video decoder of first card
- 1 = /dev/dvb/adapter0/audio0 first audio decoder of first card
- 2 = /dev/dvb/adapter0/sec0 (obsolete/unused)
- 3 = /dev/dvb/adapter0/frontend0 first frontend device of first card
- 4 = /dev/dvb/adapter0/demux0 first demux device of first card
- 5 = /dev/dvb/adapter0/dvr0 first digital video recoder device of first card
- 6 = /dev/dvb/adapter0/ca0 first common access port of first card
- 7 = /dev/dvb/adapter0/net0 first network device of first card
- 8 = /dev/dvb/adapter0/osd0 first on-screen-display device of first card
- 9 = /dev/dvb/adapter0/video1 second video decoder of first card
- ...
- 64 = /dev/dvb/adapter1/video0 first video decoder of second card
- ...
- 128 = /dev/dvb/adapter2/video0 first video decoder of third card
- ...
- 196 = /dev/dvb/adapter3/video0 first video decoder of fourth card
-
- 216 char Bluetooth RFCOMM TTY devices
- 0 = /dev/rfcomm0 First Bluetooth RFCOMM TTY device
- 1 = /dev/rfcomm1 Second Bluetooth RFCOMM TTY device
- ...
-
- 217 char Bluetooth RFCOMM TTY devices (alternate devices)
- 0 = /dev/curf0 Callout device for rfcomm0
- 1 = /dev/curf1 Callout device for rfcomm1
- ...
-
- 218 char The Logical Company bus Unibus/Qbus adapters
- 0 = /dev/logicalco/bci/0 First bus adapter
- 1 = /dev/logicalco/bci/1 First bus adapter
- ...
-
- 219 char The Logical Company DCI-1300 digital I/O card
- 0 = /dev/logicalco/dci1300/0 First DCI-1300 card
- 1 = /dev/logicalco/dci1300/1 Second DCI-1300 card
- ...
-
- 220 char Myricom Myrinet "GM" board
- 0 = /dev/myricom/gm0 First Myrinet GM board
- 1 = /dev/myricom/gmp0 First board "root access"
- 2 = /dev/myricom/gm1 Second Myrinet GM board
- 3 = /dev/myricom/gmp1 Second board "root access"
- ...
-
- 221 char VME bus
- 0 = /dev/bus/vme/m0 First master image
- 1 = /dev/bus/vme/m1 Second master image
- 2 = /dev/bus/vme/m2 Third master image
- 3 = /dev/bus/vme/m3 Fourth master image
- 4 = /dev/bus/vme/s0 First slave image
- 5 = /dev/bus/vme/s1 Second slave image
- 6 = /dev/bus/vme/s2 Third slave image
- 7 = /dev/bus/vme/s3 Fourth slave image
- 8 = /dev/bus/vme/ctl Control
-
- It is expected that all VME bus drivers will use the
- same interface. For interface documentation see
- http://www.vmelinux.org/.
-
- 224 char A2232 serial card
- 0 = /dev/ttyY0 First A2232 port
- 1 = /dev/ttyY1 Second A2232 port
- ...
-
- 225 char A2232 serial card (alternate devices)
- 0 = /dev/cuy0 Callout device for ttyY0
- 1 = /dev/cuy1 Callout device for ttyY1
- ...
-
- 226 char Direct Rendering Infrastructure (DRI)
- 0 = /dev/dri/card0 First graphics card
- 1 = /dev/dri/card1 Second graphics card
- ...
-
- 227 char IBM 3270 terminal Unix tty access
- 1 = /dev/3270/tty1 First 3270 terminal
- 2 = /dev/3270/tty2 Seconds 3270 terminal
- ...
-
- 228 char IBM 3270 terminal block-mode access
- 0 = /dev/3270/tub Controlling interface
- 1 = /dev/3270/tub1 First 3270 terminal
- 2 = /dev/3270/tub2 Second 3270 terminal
- ...
-
- 229 char IBM iSeries/pSeries virtual console
- 0 = /dev/hvc0 First console port
- 1 = /dev/hvc1 Second console port
- ...
-
- 230 char IBM iSeries virtual tape
- 0 = /dev/iseries/vt0 First virtual tape, mode 0
- 1 = /dev/iseries/vt1 Second virtual tape, mode 0
- ...
- 32 = /dev/iseries/vt0l First virtual tape, mode 1
- 33 = /dev/iseries/vt1l Second virtual tape, mode 1
- ...
- 64 = /dev/iseries/vt0m First virtual tape, mode 2
- 65 = /dev/iseries/vt1m Second virtual tape, mode 2
- ...
- 96 = /dev/iseries/vt0a First virtual tape, mode 3
- 97 = /dev/iseries/vt1a Second virtual tape, mode 3
- ...
- 128 = /dev/iseries/nvt0 First virtual tape, mode 0, no rewind
- 129 = /dev/iseries/nvt1 Second virtual tape, mode 0, no rewind
- ...
- 160 = /dev/iseries/nvt0l First virtual tape, mode 1, no rewind
- 161 = /dev/iseries/nvt1l Second virtual tape, mode 1, no rewind
- ...
- 192 = /dev/iseries/nvt0m First virtual tape, mode 2, no rewind
- 193 = /dev/iseries/nvt1m Second virtual tape, mode 2, no rewind
- ...
- 224 = /dev/iseries/nvt0a First virtual tape, mode 3, no rewind
- 225 = /dev/iseries/nvt1a Second virtual tape, mode 3, no rewind
- ...
-
- "No rewind" refers to the omission of the default
- automatic rewind on device close. The MTREW or MTOFFL
- ioctl()'s can be used to rewind the tape regardless of
- the device used to access it.
-
- 231 char InfiniBand
- 0 = /dev/infiniband/umad0
- 1 = /dev/infiniband/umad1
- ...
- 63 = /dev/infiniband/umad63 63rd InfiniBandMad device
- 64 = /dev/infiniband/issm0 First InfiniBand IsSM device
- 65 = /dev/infiniband/issm1 Second InfiniBand IsSM device
- ...
- 127 = /dev/infiniband/issm63 63rd InfiniBand IsSM device
- 128 = /dev/infiniband/uverbs0 First InfiniBand verbs device
- 129 = /dev/infiniband/uverbs1 Second InfiniBand verbs device
- ...
- 159 = /dev/infiniband/uverbs31 31st InfiniBand verbs device
-
- 232 char Biometric Devices
- 0 = /dev/biometric/sensor0/fingerprint first fingerprint sensor on first device
- 1 = /dev/biometric/sensor0/iris first iris sensor on first device
- 2 = /dev/biometric/sensor0/retina first retina sensor on first device
- 3 = /dev/biometric/sensor0/voiceprint first voiceprint sensor on first device
- 4 = /dev/biometric/sensor0/facial first facial sensor on first device
- 5 = /dev/biometric/sensor0/hand first hand sensor on first device
- ...
- 10 = /dev/biometric/sensor1/fingerprint first fingerprint sensor on second device
- ...
- 20 = /dev/biometric/sensor2/fingerprint first fingerprint sensor on third device
- ...
-
- 233 char PathScale InfiniPath interconnect
- 0 = /dev/ipath Primary device for programs (any unit)
- 1 = /dev/ipath0 Access specifically to unit 0
- 2 = /dev/ipath1 Access specifically to unit 1
- ...
- 4 = /dev/ipath3 Access specifically to unit 3
- 129 = /dev/ipath_sma Device used by Subnet Management Agent
- 130 = /dev/ipath_diag Device used by diagnostics programs
-
- 234-254 char RESERVED FOR DYNAMIC ASSIGNMENT
- Character devices that request a dynamic allocation of major number will
- take numbers starting from 254 and downward.
-
- 240-254 block LOCAL/EXPERIMENTAL USE
- Allocated for local/experimental use. For devices not
- assigned official numbers, these ranges should be
- used in order to avoid conflicting with future assignments.
-
- 255 char RESERVED
-
- 255 block RESERVED
-
- This major is reserved to assist the expansion to a
- larger number space. No device nodes with this major
- should ever be created on the filesystem.
- (This is probably not true anymore, but I'll leave it
- for now /Torben)
-
- ---LARGE MAJORS!!!!!---
-
- 256 char Equinox SST multi-port serial boards
- 0 = /dev/ttyEQ0 First serial port on first Equinox SST board
- 127 = /dev/ttyEQ127 Last serial port on first Equinox SST board
- 128 = /dev/ttyEQ128 First serial port on second Equinox SST board
- ...
- 1027 = /dev/ttyEQ1027 Last serial port on eighth Equinox SST board
-
- 256 block Resident Flash Disk Flash Translation Layer
- 0 = /dev/rfda First RFD FTL layer
- 16 = /dev/rfdb Second RFD FTL layer
- ...
- 240 = /dev/rfdp 16th RFD FTL layer
-
- 257 char Phoenix Technologies Cryptographic Services Driver
- 0 = /dev/ptlsec Crypto Services Driver
-
- 257 block SSFDC Flash Translation Layer filesystem
- 0 = /dev/ssfdca First SSFDC layer
- 8 = /dev/ssfdcb Second SSFDC layer
- 16 = /dev/ssfdcc Third SSFDC layer
- 24 = /dev/ssfdcd 4th SSFDC layer
- 32 = /dev/ssfdce 5th SSFDC layer
- 40 = /dev/ssfdcf 6th SSFDC layer
- 48 = /dev/ssfdcg 7th SSFDC layer
- 56 = /dev/ssfdch 8th SSFDC layer
-
- 258 block ROM/Flash read-only translation layer
- 0 = /dev/blockrom0 First ROM card's translation layer interface
- 1 = /dev/blockrom1 Second ROM card's translation layer interface
- ...
-
- 259 block Block Extended Major
- Used dynamically to hold additional partition minor
- numbers and allow large numbers of partitions per device
-
- 259 char FPGA configuration interfaces
- 0 = /dev/icap0 First Xilinx internal configuration
- 1 = /dev/icap1 Second Xilinx internal configuration
-
- 260 char OSD (Object-based-device) SCSI Device
- 0 = /dev/osd0 First OSD Device
- 1 = /dev/osd1 Second OSD Device
- ...
- 255 = /dev/osd255 256th OSD Device
-
-
-Additional ``/dev/`` directory entries
---------------------------------------
-
-This section details additional entries that should or may exist in
-the /dev directory. It is preferred that symbolic links use the same
-form (absolute or relative) as is indicated here. Links are
-classified as "hard" or "symbolic" depending on the preferred type of
-link; if possible, the indicated type of link should be used.
-
-Compulsory links
-++++++++++++++++
-
-These links should exist on all systems:
-
-=============== =============== =============== ===============================
-/dev/fd /proc/self/fd symbolic File descriptors
-/dev/stdin fd/0 symbolic stdin file descriptor
-/dev/stdout fd/1 symbolic stdout file descriptor
-/dev/stderr fd/2 symbolic stderr file descriptor
-/dev/nfsd socksys symbolic Required by iBCS-2
-/dev/X0R null symbolic Required by iBCS-2
-=============== =============== =============== ===============================
-
-Note: ``/dev/X0R`` is <letter X>-<digit 0>-<letter R>.
-
-Recommended links
-+++++++++++++++++
-
-It is recommended that these links exist on all systems:
-
-
-=============== =============== =============== ===============================
-/dev/core /proc/kcore symbolic Backward compatibility
-/dev/ramdisk ram0 symbolic Backward compatibility
-/dev/ftape qft0 symbolic Backward compatibility
-/dev/bttv0 video0 symbolic Backward compatibility
-/dev/radio radio0 symbolic Backward compatibility
-/dev/i2o* /dev/i2o/* symbolic Backward compatibility
-/dev/scd? sr? hard Alternate SCSI CD-ROM name
-=============== =============== =============== ===============================
-
-Locally defined links
-+++++++++++++++++++++
-
-The following links may be established locally to conform to the
-configuration of the system. This is merely a tabulation of existing
-practice, and does not constitute a recommendation. However, if they
-exist, they should have the following uses.
-
-=============== =============== =============== ===============================
-/dev/mouse mouse port symbolic Current mouse device
-/dev/tape tape device symbolic Current tape device
-/dev/cdrom CD-ROM device symbolic Current CD-ROM device
-/dev/cdwriter CD-writer symbolic Current CD-writer device
-/dev/scanner scanner symbolic Current scanner device
-/dev/modem modem port symbolic Current dialout device
-/dev/root root device symbolic Current root filesystem
-/dev/swap swap device symbolic Current swap device
-=============== =============== =============== ===============================
-
-``/dev/modem`` should not be used for a modem which supports dialin as
-well as dialout, as it tends to cause lock file problems. If it
-exists, ``/dev/modem`` should point to the appropriate primary TTY device
-(the use of the alternate callout devices is deprecated).
-
-For SCSI devices, ``/dev/tape`` and ``/dev/cdrom`` should point to the
-*cooked* devices (``/dev/st*`` and ``/dev/sr*``, respectively), whereas
-``/dev/cdwriter`` and /dev/scanner should point to the appropriate generic
-SCSI devices (/dev/sg*).
-
-``/dev/mouse`` may point to a primary serial TTY device, a hardware mouse
-device, or a socket for a mouse driver program (e.g. ``/dev/gpmdata``).
-
-Sockets and pipes
-+++++++++++++++++
-
-Non-transient sockets and named pipes may exist in /dev. Common entries are:
-
-=============== =============== ===============================================
-/dev/printer socket lpd local socket
-/dev/log socket syslog local socket
-/dev/gpmdata socket gpm mouse multiplexer
-=============== =============== ===============================================
-
-Mount points
-++++++++++++
-
-The following names are reserved for mounting special filesystems
-under /dev. These special filesystems provide kernel interfaces that
-cannot be provided with standard device nodes.
-
-=============== =============== ===============================================
-/dev/pts devpts PTY slave filesystem
-/dev/shm tmpfs POSIX shared memory maintenance access
-=============== =============== ===============================================
-
-Terminal devices
-----------------
-
-Terminal, or TTY devices are a special class of character devices. A
-terminal device is any device that could act as a controlling terminal
-for a session; this includes virtual consoles, serial ports, and
-pseudoterminals (PTYs).
-
-All terminal devices share a common set of capabilities known as line
-disciplines; these include the common terminal line discipline as well
-as SLIP and PPP modes.
-
-All terminal devices are named similarly; this section explains the
-naming and use of the various types of TTYs. Note that the naming
-conventions include several historical warts; some of these are
-Linux-specific, some were inherited from other systems, and some
-reflect Linux outgrowing a borrowed convention.
-
-A hash mark (``#``) in a device name is used here to indicate a decimal
-number without leading zeroes.
-
-Virtual consoles and the console device
-+++++++++++++++++++++++++++++++++++++++
-
-Virtual consoles are full-screen terminal displays on the system video
-monitor. Virtual consoles are named ``/dev/tty#``, with numbering
-starting at ``/dev/tty1``; ``/dev/tty0`` is the current virtual console.
-``/dev/tty0`` is the device that should be used to access the system video
-card on those architectures for which the frame buffer devices
-(``/dev/fb*``) are not applicable. Do not use ``/dev/console``
-for this purpose.
-
-The console device, ``/dev/console``, is the device to which system
-messages should be sent, and on which logins should be permitted in
-single-user mode. Starting with Linux 2.1.71, ``/dev/console`` is managed
-by the kernel; for previous versions it should be a symbolic link to
-either ``/dev/tty0``, a specific virtual console such as ``/dev/tty1``, or to
-a serial port primary (``tty*``, not ``cu*``) device, depending on the
-configuration of the system.
-
-Serial ports
-++++++++++++
-
-Serial ports are RS-232 serial ports and any device which simulates
-one, either in hardware (such as internal modems) or in software (such
-as the ISDN driver.) Under Linux, each serial ports has two device
-names, the primary or callin device and the alternate or callout one.
-Each kind of device is indicated by a different letter. For any
-letter X, the names of the devices are ``/dev/ttyX#`` and ``/dev/cux#``,
-respectively; for historical reasons, ``/dev/ttyS#`` and ``/dev/ttyC#``
-correspond to ``/dev/cua#`` and ``/dev/cub#``. In the future, it should be
-expected that multiple letters will be used; all letters will be upper
-case for the "tty" device (e.g. ``/dev/ttyDP#``) and lower case for the
-"cu" device (e.g. ``/dev/cudp#``).
-
-The names ``/dev/ttyQ#`` and ``/dev/cuq#`` are reserved for local use.
-
-The alternate devices provide for kernel-based exclusion and somewhat
-different defaults than the primary devices. Their main purpose is to
-allow the use of serial ports with programs with no inherent or broken
-support for serial ports. Their use is deprecated, and they may be
-removed from a future version of Linux.
-
-Arbitration of serial ports is provided by the use of lock files with
-the names ``/var/lock/LCK..ttyX#``. The contents of the lock file should
-be the PID of the locking process as an ASCII number.
-
-It is common practice to install links such as /dev/modem
-which point to serial ports. In order to ensure proper locking in the
-presence of these links, it is recommended that software chase
-symlinks and lock all possible names; additionally, it is recommended
-that a lock file be installed with the corresponding alternate
-device. In order to avoid deadlocks, it is recommended that the locks
-are acquired in the following order, and released in the reverse:
-
- 1. The symbolic link name, if any (``/var/lock/LCK..modem``)
- 2. The "tty" name (``/var/lock/LCK..ttyS2``)
- 3. The alternate device name (``/var/lock/LCK..cua2``)
-
-In the case of nested symbolic links, the lock files should be
-installed in the order the symlinks are resolved.
-
-Under no circumstances should an application hold a lock while waiting
-for another to be released. In addition, applications which attempt
-to create lock files for the corresponding alternate device names
-should take into account the possibility of being used on a non-serial
-port TTY, for which no alternate device would exist.
-
-Pseudoterminals (PTYs)
-++++++++++++++++++++++
-
-Pseudoterminals, or PTYs, are used to create login sessions or provide
-other capabilities requiring a TTY line discipline (including SLIP or
-PPP capability) to arbitrary data-generation processes. Each PTY has
-a master side, named ``/dev/pty[p-za-e][0-9a-f]``, and a slave side, named
-``/dev/tty[p-za-e][0-9a-f]``. The kernel arbitrates the use of PTYs by
-allowing each master side to be opened only once.
-
-Once the master side has been opened, the corresponding slave device
-can be used in the same manner as any TTY device. The master and
-slave devices are connected by the kernel, generating the equivalent
-of a bidirectional pipe with TTY capabilities.
-
-Recent versions of the Linux kernels and GNU libc contain support for
-the System V/Unix98 naming scheme for PTYs, which assigns a common
-device, ``/dev/ptmx``, to all the masters (opening it will automatically
-give you a previously unassigned PTY) and a subdirectory, ``/dev/pts``,
-for the slaves; the slaves are named with decimal integers (``/dev/pts/#``
-in our notation). This removes the problem of exhausting the
-namespace and enables the kernel to automatically create the device
-nodes for the slaves on demand using the "devpts" filesystem.
-
+++ /dev/null
-Dynamic debug
-+++++++++++++
-
-
-Introduction
-============
-
-This document describes how to use the dynamic debug (dyndbg) feature.
-
-Dynamic debug is designed to allow you to dynamically enable/disable
-kernel code to obtain additional kernel information. Currently, if
-``CONFIG_DYNAMIC_DEBUG`` is set, then all ``pr_debug()``/``dev_dbg()`` and
-``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
-enabled per-callsite.
-
-If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
-shortcut for ``print_hex_dump(KERN_DEBUG)``.
-
-For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
-its ``prefix_str`` argument, if it is constant string; or ``hexdump``
-in case ``prefix_str`` is build dynamically.
-
-Dynamic debug has even more useful features:
-
- * Simple query language allows turning on and off debugging
- statements by matching any combination of 0 or 1 of:
-
- - source filename
- - function name
- - line number (including ranges of line numbers)
- - module name
- - format string
-
- * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
- which can be read to display the complete list of known debug
- statements, to help guide you
-
-Controlling dynamic debug Behaviour
-===================================
-
-The behaviour of ``pr_debug()``/``dev_dbg()`` are controlled via writing to a
-control file in the 'debugfs' filesystem. Thus, you must first mount
-the debugfs filesystem, in order to make use of this feature.
-Subsequently, we refer to the control file as:
-``<debugfs>/dynamic_debug/control``. For example, if you want to enable
-printing from source file ``svcsock.c``, line 1603 you simply do::
-
- nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
- <debugfs>/dynamic_debug/control
-
-If you make a mistake with the syntax, the write will fail thus::
-
- nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
- <debugfs>/dynamic_debug/control
- -bash: echo: write error: Invalid argument
-
-Viewing Dynamic Debug Behaviour
-===============================
-
-You can view the currently configured behaviour of all the debug
-statements via::
-
- nullarbor:~ # cat <debugfs>/dynamic_debug/control
- # filename:lineno [module]function flags format
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline : %d\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth : %d\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests : %d\012"
- ...
-
-
-You can also apply standard Unix text manipulation filters to this
-data, e.g.::
-
- nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control | wc -l
- 62
-
- nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
- 42
-
-The third column shows the currently enabled flags for each debug
-statement callsite (see below for definitions of the flags). The
-default value, with no flags enabled, is ``=_``. So you can view all
-the debug statement callsites with any non-default flags::
-
- nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
- # filename:lineno [module]function flags format
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
-
-Command Language Reference
-==========================
-
-At the lexical level, a command comprises a sequence of words separated
-by spaces or tabs. So these are all equivalent::
-
- nullarbor:~ # echo -c 'file svcsock.c line 1603 +p' >
- <debugfs>/dynamic_debug/control
- nullarbor:~ # echo -c ' file svcsock.c line 1603 +p ' >
- <debugfs>/dynamic_debug/control
- nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
- <debugfs>/dynamic_debug/control
-
-Command submissions are bounded by a write() system call.
-Multiple commands can be written together, separated by ``;`` or ``\n``::
-
- ~# echo "func pnpacpi_get_resources +p; func pnp_assign_mem +p" \
- > <debugfs>/dynamic_debug/control
-
-If your query set is big, you can batch them too::
-
- ~# cat query-batch-file > <debugfs>/dynamic_debug/control
-
-A another way is to use wildcard. The match rule support ``*`` (matches
-zero or more characters) and ``?`` (matches exactly one character).For
-example, you can match all usb drivers::
-
- ~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
-
-At the syntactical level, a command comprises a sequence of match
-specifications, followed by a flags change specification::
-
- command ::= match-spec* flags-spec
-
-The match-spec's are used to choose a subset of the known pr_debug()
-callsites to which to apply the flags-spec. Think of them as a query
-with implicit ANDs between each pair. Note that an empty list of
-match-specs will select all debug statement callsites.
-
-A match specification comprises a keyword, which controls the
-attribute of the callsite to be compared, and a value to compare
-against. Possible keywords are:::
-
- match-spec ::= 'func' string |
- 'file' string |
- 'module' string |
- 'format' string |
- 'line' line-range
-
- line-range ::= lineno |
- '-'lineno |
- lineno'-' |
- lineno'-'lineno
-
- lineno ::= unsigned-int
-
-.. note::
-
- ``line-range`` cannot contain space, e.g.
- "1-30" is valid range but "1 - 30" is not.
-
-
-The meanings of each keyword are:
-
-func
- The given string is compared against the function name
- of each callsite. Example::
-
- func svc_tcp_accept
-
-file
- The given string is compared against either the full pathname, the
- src-root relative pathname, or the basename of the source file of
- each callsite. Examples::
-
- file svcsock.c
- file kernel/freezer.c
- file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c
-
-module
- The given string is compared against the module name
- of each callsite. The module name is the string as
- seen in ``lsmod``, i.e. without the directory or the ``.ko``
- suffix and with ``-`` changed to ``_``. Examples::
-
- module sunrpc
- module nfsd
-
-format
- The given string is searched for in the dynamic debug format
- string. Note that the string does not need to match the
- entire format, only some part. Whitespace and other
- special characters can be escaped using C octal character
- escape ``\ooo`` notation, e.g. the space character is ``\040``.
- Alternatively, the string can be enclosed in double quote
- characters (``"``) or single quote characters (``'``).
- Examples::
-
- format svcrdma: // many of the NFS/RDMA server pr_debugs
- format readahead // some pr_debugs in the readahead cache
- format nfsd:\040SETATTR // one way to match a format with whitespace
- format "nfsd: SETATTR" // a neater way to match a format with whitespace
- format 'nfsd: SETATTR' // yet another way to match a format with whitespace
-
-line
- The given line number or range of line numbers is compared
- against the line number of each ``pr_debug()`` callsite. A single
- line number matches the callsite line number exactly. A
- range of line numbers matches any callsite between the first
- and last line number inclusive. An empty first number means
- the first line in the file, an empty line number means the
- last number in the file. Examples::
-
- line 1603 // exactly line 1603
- line 1600-1605 // the six lines from line 1600 to line 1605
- line -1605 // the 1605 lines from line 1 to line 1605
- line 1600- // all lines from line 1600 to the end of the file
-
-The flags specification comprises a change operation followed
-by one or more flag characters. The change operation is one
-of the characters::
-
- - remove the given flags
- + add the given flags
- = set the flags to the given flags
-
-The flags are::
-
- p enables the pr_debug() callsite.
- f Include the function name in the printed message
- l Include line number in the printed message
- m Include module name in the printed message
- t Include thread ID in messages not generated from interrupt context
- _ No flags are set. (Or'd with others on input)
-
-For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only ``p`` flag
-have meaning, other flags ignored.
-
-For display, the flags are preceded by ``=``
-(mnemonic: what the flags are currently equal to).
-
-Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification.
-To clear all flags at once, use ``=_`` or ``-flmpt``.
-
-
-Debug messages during Boot Process
-==================================
-
-To activate debug messages for core code and built-in modules during
-the boot process, even before userspace and debugfs exists, use
-``dyndbg="QUERY"``, ``module.dyndbg="QUERY"``, or ``ddebug_query="QUERY"``
-(``ddebug_query`` is obsoleted by ``dyndbg``, and deprecated). QUERY follows
-the syntax described above, but must not exceed 1023 characters. Your
-bootloader may impose lower limits.
-
-These ``dyndbg`` params are processed just after the ddebug tables are
-processed, as part of the arch_initcall. Thus you can enable debug
-messages in all code run after this arch_initcall via this boot
-parameter.
-
-On an x86 system for example ACPI enablement is a subsys_initcall and::
-
- dyndbg="file ec.c +p"
-
-will show early Embedded Controller transactions during ACPI setup if
-your machine (typically a laptop) has an Embedded Controller.
-PCI (or other devices) initialization also is a hot candidate for using
-this boot parameter for debugging purposes.
-
-If ``foo`` module is not built-in, ``foo.dyndbg`` will still be processed at
-boot time, without effect, but will be reprocessed when module is
-loaded later. ``dyndbg_query=`` and bare ``dyndbg=`` are only processed at
-boot.
-
-
-Debug Messages at Module Initialization Time
-============================================
-
-When ``modprobe foo`` is called, modprobe scans ``/proc/cmdline`` for
-``foo.params``, strips ``foo.``, and passes them to the kernel along with
-params given in modprobe args or ``/etc/modprob.d/*.conf`` files,
-in the following order:
-
-1. parameters given via ``/etc/modprobe.d/*.conf``::
-
- options foo dyndbg=+pt
- options foo dyndbg # defaults to +p
-
-2. ``foo.dyndbg`` as given in boot args, ``foo.`` is stripped and passed::
-
- foo.dyndbg=" func bar +p; func buz +mp"
-
-3. args to modprobe::
-
- modprobe foo dyndbg==pmf # override previous settings
-
-These ``dyndbg`` queries are applied in order, with last having final say.
-This allows boot args to override or modify those from ``/etc/modprobe.d``
-(sensible, since 1 is system wide, 2 is kernel or boot specific), and
-modprobe args to override both.
-
-In the ``foo.dyndbg="QUERY"`` form, the query must exclude ``module foo``.
-``foo`` is extracted from the param-name, and applied to each query in
-``QUERY``, and only 1 match-spec of each type is allowed.
-
-The ``dyndbg`` option is a "fake" module parameter, which means:
-
-- modules do not need to define it explicitly
-- every module gets it tacitly, whether they use pr_debug or not
-- it doesn't appear in ``/sys/module/$module/parameters/``
- To see it, grep the control file, or inspect ``/proc/cmdline.``
-
-For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or
-enabled by ``-DDEBUG`` flag during compilation) can be disabled later via
-the sysfs interface if the debug messages are no longer needed::
-
- echo "module module_name -p" > <debugfs>/dynamic_debug/control
-
-Examples
-========
-
-::
-
- // enable the message at line 1603 of file svcsock.c
- nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all the messages in file svcsock.c
- nullarbor:~ # echo -n 'file svcsock.c +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all the messages in the NFS server module
- nullarbor:~ # echo -n 'module nfsd +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all 12 messages in the function svc_process()
- nullarbor:~ # echo -n 'func svc_process +p' >
- <debugfs>/dynamic_debug/control
-
- // disable all 12 messages in the function svc_process()
- nullarbor:~ # echo -n 'func svc_process -p' >
- <debugfs>/dynamic_debug/control
-
- // enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
- nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
- <debugfs>/dynamic_debug/control
-
- // enable messages in files of which the paths include string "usb"
- nullarbor:~ # echo -n '*usb* +p' > <debugfs>/dynamic_debug/control
-
- // enable all messages
- nullarbor:~ # echo -n '+p' > <debugfs>/dynamic_debug/control
-
- // add module, function to all enabled messages
- nullarbor:~ # echo -n '+mf' > <debugfs>/dynamic_debug/control
-
- // boot-args example, with newlines and comments for readability
- Kernel command line: ...
- // see whats going on in dyndbg=value processing
- dynamic_debug.verbose=1
- // enable pr_debugs in 2 builtins, #cmt is stripped
- dyndbg="module params +p #cmt ; module sys +p"
- // enable pr_debugs in 2 functions in a module loaded later
- pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p"
.. toctree::
:maxdepth: 2
+ admin-guide/index
kernel-documentation
process/index
dev-tools/tools
+++ /dev/null
-Explaining the dreaded "No init found." boot hang message
-=========================================================
-
-OK, so you've got this pretty unintuitive message (currently located
-in init/main.c) and are wondering what the H*** went wrong.
-Some high-level reasons for failure (listed roughly in order of execution)
-to load the init binary are:
-
-A) Unable to mount root FS
-B) init binary doesn't exist on rootfs
-C) broken console device
-D) binary exists but dependencies not available
-E) binary cannot be loaded
-
-Detailed explanations:
-
-A) Set "debug" kernel parameter (in bootloader config file or CONFIG_CMDLINE)
- to get more detailed kernel messages.
-B) make sure you have the correct root FS type
- (and ``root=`` kernel parameter points to the correct partition),
- required drivers such as storage hardware (such as SCSI or USB!)
- and filesystem (ext3, jffs2 etc.) are builtin (alternatively as modules,
- to be pre-loaded by an initrd)
-C) Possibly a conflict in ``console= setup`` --> initial console unavailable.
- E.g. some serial consoles are unreliable due to serial IRQ issues (e.g.
- missing interrupt-based configuration).
- Try using a different ``console= device`` or e.g. ``netconsole=``.
-D) e.g. required library dependencies of the init binary such as
- ``/lib/ld-linux.so.2`` missing or broken. Use
- ``readelf -d <INIT>|grep NEEDED`` to find out which libraries are required.
-E) make sure the binary's architecture matches your hardware.
- E.g. i386 vs. x86_64 mismatch, or trying to load x86 on ARM hardware.
- In case you tried loading a non-binary file here (shell script?),
- you should make sure that the script specifies an interpreter in its shebang
- header line (``#!/...``) that is fully working (including its library
- dependencies). And before tackling scripts, better first test a simple
- non-script binary such as ``/bin/sh`` and confirm its successful execution.
- To find out more, add code ``to init/main.c`` to display kernel_execve()s
- return values.
-
-Please extend this explanation whenever you find new failure causes
-(after all loading the init binary is a CRITICAL and hard transition step
-which needs to be made as painless as possible), then submit patch to LKML.
-Further TODOs:
-
-- Implement the various ``run_init_process()`` invocations via a struct array
- which can then store the ``kernel_execve()`` result value and on failure
- log it all by iterating over **all** results (very important usability fix).
-- try to make the implementation itself more helpful in general,
- e.g. by providing additional error messages at affected places.
-
-Andreas Mohr <andi at lisas period de>
+++ /dev/null
-Using the initial RAM disk (initrd)
-===================================
-
-Written 1996,2000 by Werner Almesberger <werner.almesberger@epfl.ch> and
-Hans Lermen <lermen@fgan.de>
-
-
-initrd provides the capability to load a RAM disk by the boot loader.
-This RAM disk can then be mounted as the root file system and programs
-can be run from it. Afterwards, a new root file system can be mounted
-from a different device. The previous root (from initrd) is then moved
-to a directory and can be subsequently unmounted.
-
-initrd is mainly designed to allow system startup to occur in two phases,
-where the kernel comes up with a minimum set of compiled-in drivers, and
-where additional modules are loaded from initrd.
-
-This document gives a brief overview of the use of initrd. A more detailed
-discussion of the boot process can be found in [#f1]_.
-
-
-Operation
----------
-
-When using initrd, the system typically boots as follows:
-
- 1) the boot loader loads the kernel and the initial RAM disk
- 2) the kernel converts initrd into a "normal" RAM disk and
- frees the memory used by initrd
- 3) if the root device is not ``/dev/ram0``, the old (deprecated)
- change_root procedure is followed. see the "Obsolete root change
- mechanism" section below.
- 4) root device is mounted. if it is ``/dev/ram0``, the initrd image is
- then mounted as root
- 5) /sbin/init is executed (this can be any valid executable, including
- shell scripts; it is run with uid 0 and can do basically everything
- init can do).
- 6) init mounts the "real" root file system
- 7) init places the root file system at the root directory using the
- pivot_root system call
- 8) init execs the ``/sbin/init`` on the new root filesystem, performing
- the usual boot sequence
- 9) the initrd file system is removed
-
-Note that changing the root directory does not involve unmounting it.
-It is therefore possible to leave processes running on initrd during that
-procedure. Also note that file systems mounted under initrd continue to
-be accessible.
-
-
-Boot command-line options
--------------------------
-
-initrd adds the following new options::
-
- initrd=<path> (e.g. LOADLIN)
-
- Loads the specified file as the initial RAM disk. When using LILO, you
- have to specify the RAM disk image file in /etc/lilo.conf, using the
- INITRD configuration variable.
-
- noinitrd
-
- initrd data is preserved but it is not converted to a RAM disk and
- the "normal" root file system is mounted. initrd data can be read
- from /dev/initrd. Note that the data in initrd can have any structure
- in this case and doesn't necessarily have to be a file system image.
- This option is used mainly for debugging.
-
- Note: /dev/initrd is read-only and it can only be used once. As soon
- as the last process has closed it, all data is freed and /dev/initrd
- can't be opened anymore.
-
- root=/dev/ram0
-
- initrd is mounted as root, and the normal boot procedure is followed,
- with the RAM disk mounted as root.
-
-Compressed cpio images
-----------------------
-
-Recent kernels have support for populating a ramdisk from a compressed cpio
-archive. On such systems, the creation of a ramdisk image doesn't need to
-involve special block devices or loopbacks; you merely create a directory on
-disk with the desired initrd content, cd to that directory, and run (as an
-example)::
-
- find . | cpio --quiet -H newc -o | gzip -9 -n > /boot/imagefile.img
-
-Examining the contents of an existing image file is just as simple::
-
- mkdir /tmp/imagefile
- cd /tmp/imagefile
- gzip -cd /boot/imagefile.img | cpio -imd --quiet
-
-Installation
-------------
-
-First, a directory for the initrd file system has to be created on the
-"normal" root file system, e.g.::
-
- # mkdir /initrd
-
-The name is not relevant. More details can be found on the
-:manpage:`pivot_root(2)` man page.
-
-If the root file system is created during the boot procedure (i.e. if
-you're building an install floppy), the root file system creation
-procedure should create the ``/initrd`` directory.
-
-If initrd will not be mounted in some cases, its content is still
-accessible if the following device has been created::
-
- # mknod /dev/initrd b 1 250
- # chmod 400 /dev/initrd
-
-Second, the kernel has to be compiled with RAM disk support and with
-support for the initial RAM disk enabled. Also, at least all components
-needed to execute programs from initrd (e.g. executable format and file
-system) must be compiled into the kernel.
-
-Third, you have to create the RAM disk image. This is done by creating a
-file system on a block device, copying files to it as needed, and then
-copying the content of the block device to the initrd file. With recent
-kernels, at least three types of devices are suitable for that:
-
- - a floppy disk (works everywhere but it's painfully slow)
- - a RAM disk (fast, but allocates physical memory)
- - a loopback device (the most elegant solution)
-
-We'll describe the loopback device method:
-
- 1) make sure loopback block devices are configured into the kernel
- 2) create an empty file system of the appropriate size, e.g.::
-
- # dd if=/dev/zero of=initrd bs=300k count=1
- # mke2fs -F -m0 initrd
-
- (if space is critical, you may want to use the Minix FS instead of Ext2)
- 3) mount the file system, e.g.::
-
- # mount -t ext2 -o loop initrd /mnt
-
- 4) create the console device::
-
- # mkdir /mnt/dev
- # mknod /mnt/dev/console c 5 1
-
- 5) copy all the files that are needed to properly use the initrd
- environment. Don't forget the most important file, ``/sbin/init``
-
- .. note:: ``/sbin/init`` permissions must include "x" (execute).
-
- 6) correct operation the initrd environment can frequently be tested
- even without rebooting with the command::
-
- # chroot /mnt /sbin/init
-
- This is of course limited to initrds that do not interfere with the
- general system state (e.g. by reconfiguring network interfaces,
- overwriting mounted devices, trying to start already running demons,
- etc. Note however that it is usually possible to use pivot_root in
- such a chroot'ed initrd environment.)
- 7) unmount the file system::
-
- # umount /mnt
-
- 8) the initrd is now in the file "initrd". Optionally, it can now be
- compressed::
-
- # gzip -9 initrd
-
-For experimenting with initrd, you may want to take a rescue floppy and
-only add a symbolic link from ``/sbin/init`` to ``/bin/sh``. Alternatively, you
-can try the experimental newlib environment [#f2]_ to create a small
-initrd.
-
-Finally, you have to boot the kernel and load initrd. Almost all Linux
-boot loaders support initrd. Since the boot process is still compatible
-with an older mechanism, the following boot command line parameters
-have to be given::
-
- root=/dev/ram0 rw
-
-(rw is only necessary if writing to the initrd file system.)
-
-With LOADLIN, you simply execute::
-
- LOADLIN <kernel> initrd=<disk_image>
-
-e.g.::
-
- LOADLIN C:\LINUX\BZIMAGE initrd=C:\LINUX\INITRD.GZ root=/dev/ram0 rw
-
-With LILO, you add the option ``INITRD=<path>`` to either the global section
-or to the section of the respective kernel in ``/etc/lilo.conf``, and pass
-the options using APPEND, e.g.::
-
- image = /bzImage
- initrd = /boot/initrd.gz
- append = "root=/dev/ram0 rw"
-
-and run ``/sbin/lilo``
-
-For other boot loaders, please refer to the respective documentation.
-
-Now you can boot and enjoy using initrd.
-
-
-Changing the root device
-------------------------
-
-When finished with its duties, init typically changes the root device
-and proceeds with starting the Linux system on the "real" root device.
-
-The procedure involves the following steps:
- - mounting the new root file system
- - turning it into the root file system
- - removing all accesses to the old (initrd) root file system
- - unmounting the initrd file system and de-allocating the RAM disk
-
-Mounting the new root file system is easy: it just needs to be mounted on
-a directory under the current root. Example::
-
- # mkdir /new-root
- # mount -o ro /dev/hda1 /new-root
-
-The root change is accomplished with the pivot_root system call, which
-is also available via the ``pivot_root`` utility (see :manpage:`pivot_root(8)`
-man page; ``pivot_root`` is distributed with util-linux version 2.10h or higher
-[#f3]_). ``pivot_root`` moves the current root to a directory under the new
-root, and puts the new root at its place. The directory for the old root
-must exist before calling ``pivot_root``. Example::
-
- # cd /new-root
- # mkdir initrd
- # pivot_root . initrd
-
-Now, the init process may still access the old root via its
-executable, shared libraries, standard input/output/error, and its
-current root directory. All these references are dropped by the
-following command::
-
- # exec chroot . what-follows <dev/console >dev/console 2>&1
-
-Where what-follows is a program under the new root, e.g. ``/sbin/init``
-If the new root file system will be used with udev and has no valid
-``/dev`` directory, udev must be initialized before invoking chroot in order
-to provide ``/dev/console``.
-
-Note: implementation details of pivot_root may change with time. In order
-to ensure compatibility, the following points should be observed:
-
- - before calling pivot_root, the current directory of the invoking
- process should point to the new root directory
- - use . as the first argument, and the _relative_ path of the directory
- for the old root as the second argument
- - a chroot program must be available under the old and the new root
- - chroot to the new root afterwards
- - use relative paths for dev/console in the exec command
-
-Now, the initrd can be unmounted and the memory allocated by the RAM
-disk can be freed::
-
- # umount /initrd
- # blockdev --flushbufs /dev/ram0
-
-It is also possible to use initrd with an NFS-mounted root, see the
-:manpage:`pivot_root(8)` man page for details.
-
-
-Usage scenarios
----------------
-
-The main motivation for implementing initrd was to allow for modular
-kernel configuration at system installation. The procedure would work
-as follows:
-
- 1) system boots from floppy or other media with a minimal kernel
- (e.g. support for RAM disks, initrd, a.out, and the Ext2 FS) and
- loads initrd
- 2) ``/sbin/init`` determines what is needed to (1) mount the "real" root FS
- (i.e. device type, device drivers, file system) and (2) the
- distribution media (e.g. CD-ROM, network, tape, ...). This can be
- done by asking the user, by auto-probing, or by using a hybrid
- approach.
- 3) ``/sbin/init`` loads the necessary kernel modules
- 4) ``/sbin/init`` creates and populates the root file system (this doesn't
- have to be a very usable system yet)
- 5) ``/sbin/init`` invokes ``pivot_root`` to change the root file system and
- execs - via chroot - a program that continues the installation
- 6) the boot loader is installed
- 7) the boot loader is configured to load an initrd with the set of
- modules that was used to bring up the system (e.g. ``/initrd`` can be
- modified, then unmounted, and finally, the image is written from
- ``/dev/ram0`` or ``/dev/rd/0`` to a file)
- 8) now the system is bootable and additional installation tasks can be
- performed
-
-The key role of initrd here is to re-use the configuration data during
-normal system operation without requiring the use of a bloated "generic"
-kernel or re-compiling or re-linking the kernel.
-
-A second scenario is for installations where Linux runs on systems with
-different hardware configurations in a single administrative domain. In
-such cases, it is desirable to generate only a small set of kernels
-(ideally only one) and to keep the system-specific part of configuration
-information as small as possible. In this case, a common initrd could be
-generated with all the necessary modules. Then, only ``/sbin/init`` or a file
-read by it would have to be different.
-
-A third scenario is more convenient recovery disks, because information
-like the location of the root FS partition doesn't have to be provided at
-boot time, but the system loaded from initrd can invoke a user-friendly
-dialog and it can also perform some sanity checks (or even some form of
-auto-detection).
-
-Last not least, CD-ROM distributors may use it for better installation
-from CD, e.g. by using a boot floppy and bootstrapping a bigger RAM disk
-via initrd from CD; or by booting via a loader like ``LOADLIN`` or directly
-from the CD-ROM, and loading the RAM disk from CD without need of
-floppies.
-
-
-Obsolete root change mechanism
-------------------------------
-
-The following mechanism was used before the introduction of pivot_root.
-Current kernels still support it, but you should _not_ rely on its
-continued availability.
-
-It works by mounting the "real" root device (i.e. the one set with rdev
-in the kernel image or with root=... at the boot command line) as the
-root file system when linuxrc exits. The initrd file system is then
-unmounted, or, if it is still busy, moved to a directory ``/initrd``, if
-such a directory exists on the new root file system.
-
-In order to use this mechanism, you do not have to specify the boot
-command options root, init, or rw. (If specified, they will affect
-the real root file system, not the initrd environment.)
-
-If /proc is mounted, the "real" root device can be changed from within
-linuxrc by writing the number of the new root FS device to the special
-file /proc/sys/kernel/real-root-dev, e.g.::
-
- # echo 0x301 >/proc/sys/kernel/real-root-dev
-
-Note that the mechanism is incompatible with NFS and similar file
-systems.
-
-This old, deprecated mechanism is commonly called ``change_root``, while
-the new, supported mechanism is called ``pivot_root``.
-
-
-Mixed change_root and pivot_root mechanism
-------------------------------------------
-
-In case you did not want to use ``root=/dev/ram0`` to trigger the pivot_root
-mechanism, you may create both ``/linuxrc`` and ``/sbin/init`` in your initrd
-image.
-
-``/linuxrc`` would contain only the following::
-
- #! /bin/sh
- mount -n -t proc proc /proc
- echo 0x0100 >/proc/sys/kernel/real-root-dev
- umount -n /proc
-
-Once linuxrc exited, the kernel would mount again your initrd as root,
-this time executing ``/sbin/init``. Again, it would be the duty of this init
-to build the right environment (maybe using the ``root= device`` passed on
-the cmdline) before the final execution of the real ``/sbin/init``.
-
-
-Resources
----------
-
-.. [#f1] Almesberger, Werner; "Booting Linux: The History and the Future"
- http://www.almesberger.net/cv/papers/ols2k-9.ps.gz
-.. [#f2] newlib package (experimental), with initrd example
- https://www.sourceware.org/newlib/
-.. [#f3] util-linux: Miscellaneous utilities for Linux
- https://www.kernel.org/pub/linux/utils/util-linux/
+++ /dev/null
-Java(tm) Binary Kernel Support for Linux v1.03
-----------------------------------------------
-
-Linux beats them ALL! While all other OS's are TALKING about direct
-support of Java Binaries in the OS, Linux is doing it!
-
-You can execute Java applications and Java Applets just like any
-other program after you have done the following:
-
-1) You MUST FIRST install the Java Developers Kit for Linux.
- The Java on Linux HOWTO gives the details on getting and
- installing this. This HOWTO can be found at:
-
- ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/Java-HOWTO
-
- You should also set up a reasonable CLASSPATH environment
- variable to use Java applications that make use of any
- nonstandard classes (not included in the same directory
- as the application itself).
-
-2) You have to compile BINFMT_MISC either as a module or into
- the kernel (``CONFIG_BINFMT_MISC``) and set it up properly.
- If you choose to compile it as a module, you will have
- to insert it manually with modprobe/insmod, as kmod
- cannot easily be supported with binfmt_misc.
- Read the file 'binfmt_misc.txt' in this directory to know
- more about the configuration process.
-
-3) Add the following configuration items to binfmt_misc
- (you should really have read ``binfmt_misc.txt`` now):
- support for Java applications::
-
- ':Java:M::\xca\xfe\xba\xbe::/usr/local/bin/javawrapper:'
-
- support for executable Jar files::
-
- ':ExecutableJAR:E::jar::/usr/local/bin/jarwrapper:'
-
- support for Java Applets::
-
- ':Applet:E::html::/usr/bin/appletviewer:'
-
- or the following, if you want to be more selective::
-
- ':Applet:M::<!--applet::/usr/bin/appletviewer:'
-
- Of course you have to fix the path names. The path/file names given in this
- document match the Debian 2.1 system. (i.e. jdk installed in ``/usr``,
- custom wrappers from this document in ``/usr/local``)
-
- Note, that for the more selective applet support you have to modify
- existing html-files to contain ``<!--applet-->`` in the first line
- (``<`` has to be the first character!) to let this work!
-
- For the compiled Java programs you need a wrapper script like the
- following (this is because Java is broken in case of the filename
- handling), again fix the path names, both in the script and in the
- above given configuration string.
-
- You, too, need the little program after the script. Compile like::
-
- gcc -O2 -o javaclassname javaclassname.c
-
- and stick it to ``/usr/local/bin``.
-
- Both the javawrapper shellscript and the javaclassname program
- were supplied by Colin J. Watson <cjw44@cam.ac.uk>.
-
-Javawrapper shell script::
-
- #!/bin/bash
- # /usr/local/bin/javawrapper - the wrapper for binfmt_misc/java
-
- if [ -z "$1" ]; then
- exec 1>&2
- echo Usage: $0 class-file
- exit 1
- fi
-
- CLASS=$1
- FQCLASS=`/usr/local/bin/javaclassname $1`
- FQCLASSN=`echo $FQCLASS | sed -e 's/^.*\.\([^.]*\)$/\1/'`
- FQCLASSP=`echo $FQCLASS | sed -e 's-\.-/-g' -e 's-^[^/]*$--' -e 's-/[^/]*$--'`
-
- # for example:
- # CLASS=Test.class
- # FQCLASS=foo.bar.Test
- # FQCLASSN=Test
- # FQCLASSP=foo/bar
-
- unset CLASSBASE
-
- declare -i LINKLEVEL=0
-
- while :; do
- if [ "`basename $CLASS .class`" == "$FQCLASSN" ]; then
- # See if this directory works straight off
- cd -L `dirname $CLASS`
- CLASSDIR=$PWD
- cd $OLDPWD
- if echo $CLASSDIR | grep -q "$FQCLASSP$"; then
- CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."`
- break;
- fi
- # Try dereferencing the directory name
- cd -P `dirname $CLASS`
- CLASSDIR=$PWD
- cd $OLDPWD
- if echo $CLASSDIR | grep -q "$FQCLASSP$"; then
- CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."`
- break;
- fi
- # If no other possible filename exists
- if [ ! -L $CLASS ]; then
- exec 1>&2
- echo $0:
- echo " $CLASS should be in a" \
- "directory tree called $FQCLASSP"
- exit 1
- fi
- fi
- if [ ! -L $CLASS ]; then break; fi
- # Go down one more level of symbolic links
- let LINKLEVEL+=1
- if [ $LINKLEVEL -gt 5 ]; then
- exec 1>&2
- echo $0:
- echo " Too many symbolic links encountered"
- exit 1
- fi
- CLASS=`ls --color=no -l $CLASS | sed -e 's/^.* \([^ ]*\)$/\1/'`
- done
-
- if [ -z "$CLASSBASE" ]; then
- if [ -z "$FQCLASSP" ]; then
- GOODNAME=$FQCLASSN.class
- else
- GOODNAME=$FQCLASSP/$FQCLASSN.class
- fi
- exec 1>&2
- echo $0:
- echo " $FQCLASS should be in a file called $GOODNAME"
- exit 1
- fi
-
- if ! echo $CLASSPATH | grep -q "^\(.*:\)*$CLASSBASE\(:.*\)*"; then
- # class is not in CLASSPATH, so prepend dir of class to CLASSPATH
- if [ -z "${CLASSPATH}" ] ; then
- export CLASSPATH=$CLASSBASE
- else
- export CLASSPATH=$CLASSBASE:$CLASSPATH
- fi
- fi
-
- shift
- /usr/bin/java $FQCLASS "$@"
-
-javaclassname.c::
-
- /* javaclassname.c
- *
- * Extracts the class name from a Java class file; intended for use in a Java
- * wrapper of the type supported by the binfmt_misc option in the Linux kernel.
- *
- * Copyright (C) 1999 Colin J. Watson <cjw44@cam.ac.uk>.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
- #include <stdlib.h>
- #include <stdio.h>
- #include <stdarg.h>
- #include <sys/types.h>
-
- /* From Sun's Java VM Specification, as tag entries in the constant pool. */
-
- #define CP_UTF8 1
- #define CP_INTEGER 3
- #define CP_FLOAT 4
- #define CP_LONG 5
- #define CP_DOUBLE 6
- #define CP_CLASS 7
- #define CP_STRING 8
- #define CP_FIELDREF 9
- #define CP_METHODREF 10
- #define CP_INTERFACEMETHODREF 11
- #define CP_NAMEANDTYPE 12
- #define CP_METHODHANDLE 15
- #define CP_METHODTYPE 16
- #define CP_INVOKEDYNAMIC 18
-
- /* Define some commonly used error messages */
-
- #define seek_error() error("%s: Cannot seek\n", program)
- #define corrupt_error() error("%s: Class file corrupt\n", program)
- #define eof_error() error("%s: Unexpected end of file\n", program)
- #define utf8_error() error("%s: Only ASCII 1-255 supported\n", program);
-
- char *program;
-
- long *pool;
-
- u_int8_t read_8(FILE *classfile);
- u_int16_t read_16(FILE *classfile);
- void skip_constant(FILE *classfile, u_int16_t *cur);
- void error(const char *format, ...);
- int main(int argc, char **argv);
-
- /* Reads in an unsigned 8-bit integer. */
- u_int8_t read_8(FILE *classfile)
- {
- int b = fgetc(classfile);
- if(b == EOF)
- eof_error();
- return (u_int8_t)b;
- }
-
- /* Reads in an unsigned 16-bit integer. */
- u_int16_t read_16(FILE *classfile)
- {
- int b1, b2;
- b1 = fgetc(classfile);
- if(b1 == EOF)
- eof_error();
- b2 = fgetc(classfile);
- if(b2 == EOF)
- eof_error();
- return (u_int16_t)((b1 << 8) | b2);
- }
-
- /* Reads in a value from the constant pool. */
- void skip_constant(FILE *classfile, u_int16_t *cur)
- {
- u_int16_t len;
- int seekerr = 1;
- pool[*cur] = ftell(classfile);
- switch(read_8(classfile))
- {
- case CP_UTF8:
- len = read_16(classfile);
- seekerr = fseek(classfile, len, SEEK_CUR);
- break;
- case CP_CLASS:
- case CP_STRING:
- case CP_METHODTYPE:
- seekerr = fseek(classfile, 2, SEEK_CUR);
- break;
- case CP_METHODHANDLE:
- seekerr = fseek(classfile, 3, SEEK_CUR);
- break;
- case CP_INTEGER:
- case CP_FLOAT:
- case CP_FIELDREF:
- case CP_METHODREF:
- case CP_INTERFACEMETHODREF:
- case CP_NAMEANDTYPE:
- case CP_INVOKEDYNAMIC:
- seekerr = fseek(classfile, 4, SEEK_CUR);
- break;
- case CP_LONG:
- case CP_DOUBLE:
- seekerr = fseek(classfile, 8, SEEK_CUR);
- ++(*cur);
- break;
- default:
- corrupt_error();
- }
- if(seekerr)
- seek_error();
- }
-
- void error(const char *format, ...)
- {
- va_list ap;
- va_start(ap, format);
- vfprintf(stderr, format, ap);
- va_end(ap);
- exit(1);
- }
-
- int main(int argc, char **argv)
- {
- FILE *classfile;
- u_int16_t cp_count, i, this_class, classinfo_ptr;
- u_int8_t length;
-
- program = argv[0];
-
- if(!argv[1])
- error("%s: Missing input file\n", program);
- classfile = fopen(argv[1], "rb");
- if(!classfile)
- error("%s: Error opening %s\n", program, argv[1]);
-
- if(fseek(classfile, 8, SEEK_SET)) /* skip magic and version numbers */
- seek_error();
- cp_count = read_16(classfile);
- pool = calloc(cp_count, sizeof(long));
- if(!pool)
- error("%s: Out of memory for constant pool\n", program);
-
- for(i = 1; i < cp_count; ++i)
- skip_constant(classfile, &i);
- if(fseek(classfile, 2, SEEK_CUR)) /* skip access flags */
- seek_error();
-
- this_class = read_16(classfile);
- if(this_class < 1 || this_class >= cp_count)
- corrupt_error();
- if(!pool[this_class] || pool[this_class] == -1)
- corrupt_error();
- if(fseek(classfile, pool[this_class] + 1, SEEK_SET))
- seek_error();
-
- classinfo_ptr = read_16(classfile);
- if(classinfo_ptr < 1 || classinfo_ptr >= cp_count)
- corrupt_error();
- if(!pool[classinfo_ptr] || pool[classinfo_ptr] == -1)
- corrupt_error();
- if(fseek(classfile, pool[classinfo_ptr] + 1, SEEK_SET))
- seek_error();
-
- length = read_16(classfile);
- for(i = 0; i < length; ++i)
- {
- u_int8_t x = read_8(classfile);
- if((x & 0x80) || !x)
- {
- if((x & 0xE0) == 0xC0)
- {
- u_int8_t y = read_8(classfile);
- if((y & 0xC0) == 0x80)
- {
- int c = ((x & 0x1f) << 6) + (y & 0x3f);
- if(c) putchar(c);
- else utf8_error();
- }
- else utf8_error();
- }
- else utf8_error();
- }
- else if(x == '/') putchar('.');
- else putchar(x);
- }
- putchar('\n');
- free(pool);
- fclose(classfile);
- return 0;
- }
-
-jarwrapper::
-
- #!/bin/bash
- # /usr/local/java/bin/jarwrapper - the wrapper for binfmt_misc/jar
-
- java -jar $1
-
-
-Now simply ``chmod +x`` the ``.class``, ``.jar`` and/or ``.html`` files you
-want to execute.
-
-To add a Java program to your path best put a symbolic link to the main
-.class file into /usr/bin (or another place you like) omitting the .class
-extension. The directory containing the original .class file will be
-added to your CLASSPATH during execution.
-
-
-To test your new setup, enter in the following simple Java app, and name
-it "HelloWorld.java"::
-
- class HelloWorld {
- public static void main(String args[]) {
- System.out.println("Hello World!");
- }
- }
-
-Now compile the application with::
-
- javac HelloWorld.java
-
-Set the executable permissions of the binary file, with::
-
- chmod 755 HelloWorld.class
-
-And then execute it::
-
- ./HelloWorld.class
-
-
-To execute Java Jar files, simple chmod the ``*.jar`` files to include
-the execution bit, then just do::
-
- ./Application.jar
-
-
-To execute Java Applets, simple chmod the ``*.html`` files to include
-the execution bit, then just do::
-
- ./Applet.html
-
-
-originally by Brian A. Lantz, brian@lantz.com
-heavily edited for binfmt_misc by Richard Günther
-new scripts by Colin J. Watson <cjw44@cam.ac.uk>
-added executable Jar file support by Kurt Huwig <kurt@iku-netz.de>
-
+++ /dev/null
-Kernel Parameters
-~~~~~~~~~~~~~~~~~
-
-The following is a consolidated list of the kernel parameters as
-implemented by the __setup(), core_param() and module_param() macros
-and sorted into English Dictionary order (defined as ignoring all
-punctuation and sorting digits before letters in a case insensitive
-manner), and with descriptions where known.
-
-The kernel parses parameters from the kernel command line up to "--";
-if it doesn't recognize a parameter and it doesn't contain a '.', the
-parameter gets passed to init: parameters with '=' go into init's
-environment, others are passed as command line arguments to init.
-Everything after "--" is passed as an argument to init.
-
-Module parameters can be specified in two ways: via the kernel command
-line with a module name prefix, or via modprobe, e.g.::
-
- (kernel command line) usbcore.blinkenlights=1
- (modprobe command line) modprobe usbcore blinkenlights=1
-
-Parameters for modules which are built into the kernel need to be
-specified on the kernel command line. modprobe looks through the
-kernel command line (/proc/cmdline) and collects module parameters
-when it loads a module, so the kernel command line can be used for
-loadable modules too.
-
-Hyphens (dashes) and underscores are equivalent in parameter names, so::
-
- log_buf_len=1M print-fatal-signals=1
-
-can also be entered as::
-
- log-buf-len=1M print_fatal_signals=1
-
-Double-quotes can be used to protect spaces in values, e.g.::
-
- param="spaces in here"
-
-cpu lists:
-----------
-
-Some kernel parameters take a list of CPUs as a value, e.g. isolcpus,
-nohz_full, irqaffinity, rcu_nocbs. The format of this list is:
-
- <cpu number>,...,<cpu number>
-
-or
-
- <cpu number>-<cpu number>
- (must be a positive range in ascending order)
-
-or a mixture
-
-<cpu number>,...,<cpu number>-<cpu number>
-
-Note that for the special case of a range one can split the range into equal
-sized groups and for each group use some amount from the beginning of that
-group:
-
- <cpu number>-cpu number>:<used size>/<group size>
-
-For example one can add to the command line following parameter:
-
- isolcpus=1,2,10-20,100-2000:2/25
-
-where the final item represents CPUs 100,101,125,126,150,151,...
-
-
-
-This document may not be entirely up to date and comprehensive. The command
-"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
-module. Loadable modules, after being loaded into the running kernel, also
-reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
-parameters may be changed at runtime by the command
-``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``.
-
-The parameters listed below are only valid if certain kernel build options were
-enabled and if respective hardware is present. The text in square brackets at
-the beginning of each description states the restrictions within which a
-parameter is applicable::
-
- ACPI ACPI support is enabled.
- AGP AGP (Accelerated Graphics Port) is enabled.
- ALSA ALSA sound support is enabled.
- APIC APIC support is enabled.
- APM Advanced Power Management support is enabled.
- ARM ARM architecture is enabled.
- AVR32 AVR32 architecture is enabled.
- AX25 Appropriate AX.25 support is enabled.
- BLACKFIN Blackfin architecture is enabled.
- CLK Common clock infrastructure is enabled.
- CMA Contiguous Memory Area support is enabled.
- DRM Direct Rendering Management support is enabled.
- DYNAMIC_DEBUG Build in debug messages and enable them at runtime
- EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
- EFI EFI Partitioning (GPT) is enabled
- EIDE EIDE/ATAPI support is enabled.
- EVM Extended Verification Module
- FB The frame buffer device is enabled.
- FTRACE Function tracing enabled.
- GCOV GCOV profiling is enabled.
- HW Appropriate hardware is enabled.
- IA-64 IA-64 architecture is enabled.
- IMA Integrity measurement architecture is enabled.
- IOSCHED More than one I/O scheduler is enabled.
- IP_PNP IP DHCP, BOOTP, or RARP is enabled.
- IPV6 IPv6 support is enabled.
- ISAPNP ISA PnP code is enabled.
- ISDN Appropriate ISDN support is enabled.
- JOY Appropriate joystick support is enabled.
- KGDB Kernel debugger support is enabled.
- KVM Kernel Virtual Machine support is enabled.
- LIBATA Libata driver is enabled
- LP Printer support is enabled.
- LOOP Loopback device support is enabled.
- M68k M68k architecture is enabled.
- These options have more detailed description inside of
- Documentation/m68k/kernel-options.txt.
- MDA MDA console support is enabled.
- MIPS MIPS architecture is enabled.
- MOUSE Appropriate mouse support is enabled.
- MSI Message Signaled Interrupts (PCI).
- MTD MTD (Memory Technology Device) support is enabled.
- NET Appropriate network support is enabled.
- NUMA NUMA support is enabled.
- NFS Appropriate NFS support is enabled.
- OSS OSS sound support is enabled.
- PV_OPS A paravirtualized kernel is enabled.
- PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
- PARISC The PA-RISC architecture is enabled.
- PCI PCI bus support is enabled.
- PCIE PCI Express support is enabled.
- PCMCIA The PCMCIA subsystem is enabled.
- PNP Plug & Play support is enabled.
- PPC PowerPC architecture is enabled.
- PPT Parallel port support is enabled.
- PS2 Appropriate PS/2 support is enabled.
- RAM RAM disk support is enabled.
- S390 S390 architecture is enabled.
- SCSI Appropriate SCSI support is enabled.
- A lot of drivers have their options described inside
- the Documentation/scsi/ sub-directory.
- SECURITY Different security models are enabled.
- SELINUX SELinux support is enabled.
- APPARMOR AppArmor support is enabled.
- SERIAL Serial support is enabled.
- SH SuperH architecture is enabled.
- SMP The kernel is an SMP kernel.
- SPARC Sparc architecture is enabled.
- SWSUSP Software suspend (hibernation) is enabled.
- SUSPEND System suspend states are enabled.
- TPM TPM drivers are enabled.
- TS Appropriate touchscreen support is enabled.
- UMS USB Mass Storage support is enabled.
- USB USB support is enabled.
- USBHID USB Human Interface Device support is enabled.
- V4L Video For Linux support is enabled.
- VMMIO Driver for memory mapped virtio devices is enabled.
- VGA The VGA console has been enabled.
- VT Virtual terminal support is enabled.
- WDT Watchdog support is enabled.
- XT IBM PC/XT MFM hard disk support is enabled.
- X86-32 X86-32, aka i386 architecture is enabled.
- X86-64 X86-64 architecture is enabled.
- More X86-64 boot options can be found in
- Documentation/x86/x86_64/boot-options.txt .
- X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
- X86_UV SGI UV support is enabled.
- XEN Xen support is enabled
-
-In addition, the following text indicates that the option::
-
- BUGS= Relates to possible processor bugs on the said processor.
- KNL Is a kernel start-up parameter.
- BOOT Is a boot loader parameter.
-
-Parameters denoted with BOOT are actually interpreted by the boot
-loader, and have no meaning to the kernel directly.
-Do not modify the syntax of boot loader parameters without extreme
-need or coordination with <Documentation/x86/boot.txt>.
-
-There are also arch-specific kernel-parameters not documented here.
-See for example <Documentation/x86/x86_64/boot-options.txt>.
-
-Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
-a trailing = on the name of any parameter states that that parameter will
-be entered as an environment variable, whereas its absence indicates that
-it will appear as a kernel argument readable via /proc/cmdline by programs
-running once the system is up.
-
-The number of kernel parameters is not limited, but the length of the
-complete command line (parameters including spaces etc.) is limited to
-a fixed number of characters. This limit depends on the architecture
-and is between 256 and 4096 characters. It is defined in the file
-./include/asm/setup.h as COMMAND_LINE_SIZE.
-
-Finally, the [KMG] suffix is commonly described after a number of kernel
-parameter values. These 'K', 'M', and 'G' letters represent the _binary_
-multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
-bytes respectively. Such letter suffixes can also be entirely omitted::
-
-
- acpi= [HW,ACPI,X86,ARM64]
- Advanced Configuration and Power Interface
- Format: { force | on | off | strict | noirq | rsdt |
- copy_dsdt }
- force -- enable ACPI if default was off
- on -- enable ACPI but allow fallback to DT [arm64]
- off -- disable ACPI if default was on
- noirq -- do not use ACPI for IRQ routing
- strict -- Be less tolerant of platforms that are not
- strictly ACPI specification compliant.
- rsdt -- prefer RSDT over (default) XSDT
- copy_dsdt -- copy DSDT to memory
- For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force"
- are available
-
- See also Documentation/power/runtime_pm.txt, pci=noacpi
-
- acpi_apic_instance= [ACPI, IOAPIC]
- Format: <int>
- 2: use 2nd APIC table, if available
- 1,0: use 1st APIC table
- default: 0
-
- acpi_backlight= [HW,ACPI]
- acpi_backlight=vendor
- acpi_backlight=video
- If set to vendor, prefer vendor specific driver
- (e.g. thinkpad_acpi, sony_acpi, etc.) instead
- of the ACPI video.ko driver.
-
- acpi_force_32bit_fadt_addr
- force FADT to use 32 bit addresses rather than the
- 64 bit X_* addresses. Some firmware have broken 64
- bit addresses for force ACPI ignore these and use
- the older legacy 32 bit addresses.
-
- acpica_no_return_repair [HW, ACPI]
- Disable AML predefined validation mechanism
- This mechanism can repair the evaluation result to make
- the return objects more ACPI specification compliant.
- This option is useful for developers to identify the
- root cause of an AML interpreter issue when the issue
- has something to do with the repair mechanism.
-
- acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
- acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
- Format: <int>
- CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
- debug output. Bits in debug_layer correspond to a
- _COMPONENT in an ACPI source file, e.g.,
- #define _COMPONENT ACPI_PCI_COMPONENT
- Bits in debug_level correspond to a level in
- ACPI_DEBUG_PRINT statements, e.g.,
- ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
- The debug_level mask defaults to "info". See
- Documentation/acpi/debug.txt for more information about
- debug layers and levels.
-
- Enable processor driver info messages:
- acpi.debug_layer=0x20000000
- Enable PCI/PCI interrupt routing info messages:
- acpi.debug_layer=0x400000
- Enable AML "Debug" output, i.e., stores to the Debug
- object while interpreting AML:
- acpi.debug_layer=0xffffffff acpi.debug_level=0x2
- Enable all messages related to ACPI hardware:
- acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
-
- Some values produce so much output that the system is
- unusable. The "log_buf_len" parameter may be useful
- if you need to capture more output.
-
- acpi_enforce_resources= [ACPI]
- { strict | lax | no }
- Check for resource conflicts between native drivers
- and ACPI OperationRegions (SystemIO and SystemMemory
- only). IO ports and memory declared in ACPI might be
- used by the ACPI subsystem in arbitrary AML code and
- can interfere with legacy drivers.
- strict (default): access to resources claimed by ACPI
- is denied; legacy drivers trying to access reserved
- resources will fail to bind to device using them.
- lax: access to resources claimed by ACPI is allowed;
- legacy drivers trying to access reserved resources
- will bind successfully but a warning message is logged.
- no: ACPI OperationRegions are not marked as reserved,
- no further checks are performed.
-
- acpi_force_table_verification [HW,ACPI]
- Enable table checksum verification during early stage.
- By default, this is disabled due to x86 early mapping
- size limitation.
-
- acpi_irq_balance [HW,ACPI]
- ACPI will balance active IRQs
- default in APIC mode
-
- acpi_irq_nobalance [HW,ACPI]
- ACPI will not move active IRQs (default)
- default in PIC mode
-
- acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
- Format: <irq>,<irq>...
-
- acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
- use by PCI
- Format: <irq>,<irq>...
-
- acpi_no_auto_serialize [HW,ACPI]
- Disable auto-serialization of AML methods
- AML control methods that contain the opcodes to create
- named objects will be marked as "Serialized" by the
- auto-serialization feature.
- This feature is enabled by default.
- This option allows to turn off the feature.
-
- acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
- kernels.
-
- acpi_no_static_ssdt [HW,ACPI]
- Disable installation of static SSDTs at early boot time
- By default, SSDTs contained in the RSDT/XSDT will be
- installed automatically and they will appear under
- /sys/firmware/acpi/tables.
- This option turns off this feature.
- Note that specifying this option does not affect
- dynamic table installation which will install SSDT
- tables to /sys/firmware/acpi/tables/dynamic.
-
- acpi_rsdp= [ACPI,EFI,KEXEC]
- Pass the RSDP address to the kernel, mostly used
- on machines running EFI runtime service to boot the
- second kernel for kdump.
-
- acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
- Format: To spoof as Windows 98: ="Microsoft Windows"
-
- acpi_rev_override [ACPI] Override the _REV object to return 5 (instead
- of 2 which is mandated by ACPI 6) as the supported ACPI
- specification revision (when using this switch, it may
- be necessary to carry out a cold reboot _twice_ in a
- row to make it take effect on the platform firmware).
-
- acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
- acpi_osi="string1" # add string1
- acpi_osi="!string2" # remove string2
- acpi_osi=!* # remove all strings
- acpi_osi=! # disable all built-in OS vendor
- strings
- acpi_osi=!! # enable all built-in OS vendor
- strings
- acpi_osi= # disable all strings
-
- 'acpi_osi=!' can be used in combination with single or
- multiple 'acpi_osi="string1"' to support specific OS
- vendor string(s). Note that such command can only
- affect the default state of the OS vendor strings, thus
- it cannot affect the default state of the feature group
- strings and the current state of the OS vendor strings,
- specifying it multiple times through kernel command line
- is meaningless. This command is useful when one do not
- care about the state of the feature group strings which
- should be controlled by the OSPM.
- Examples:
- 1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
- to 'acpi_osi="Windows 2000" acpi_osi=!', they all
- can make '_OSI("Windows 2000")' TRUE.
-
- 'acpi_osi=' cannot be used in combination with other
- 'acpi_osi=' command lines, the _OSI method will not
- exist in the ACPI namespace. NOTE that such command can
- only affect the _OSI support state, thus specifying it
- multiple times through kernel command line is also
- meaningless.
- Examples:
- 1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
- FALSE.
-
- 'acpi_osi=!*' can be used in combination with single or
- multiple 'acpi_osi="string1"' to support specific
- string(s). Note that such command can affect the
- current state of both the OS vendor strings and the
- feature group strings, thus specifying it multiple times
- through kernel command line is meaningful. But it may
- still not able to affect the final state of a string if
- there are quirks related to this string. This command
- is useful when one want to control the state of the
- feature group strings to debug BIOS issues related to
- the OSPM features.
- Examples:
- 1. 'acpi_osi="Module Device" acpi_osi=!*' can make
- '_OSI("Module Device")' FALSE.
- 2. 'acpi_osi=!* acpi_osi="Module Device"' can make
- '_OSI("Module Device")' TRUE.
- 3. 'acpi_osi=! acpi_osi=!* acpi_osi="Windows 2000"' is
- equivalent to
- 'acpi_osi=!* acpi_osi=! acpi_osi="Windows 2000"'
- and
- 'acpi_osi=!* acpi_osi="Windows 2000" acpi_osi=!',
- they all will make '_OSI("Windows 2000")' TRUE.
-
- acpi_pm_good [X86]
- Override the pmtimer bug detection: force the kernel
- to assume that this machine's pmtimer latches its value
- and always returns good values.
-
- acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
- Format: { level | edge | high | low }
-
- acpi_skip_timer_override [HW,ACPI]
- Recognize and ignore IRQ0/pin2 Interrupt Override.
- For broken nForce2 BIOS resulting in XT-PIC timer.
-
- acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
- old_ordering, nonvs, sci_force_enable }
- See Documentation/power/video.txt for information on
- s3_bios and s3_mode.
- s3_beep is for debugging; it makes the PC's speaker beep
- as soon as the kernel's real-mode entry point is called.
- s4_nohwsig prevents ACPI hardware signature from being
- used during resume from hibernation.
- old_ordering causes the ACPI 1.0 ordering of the _PTS
- control method, with respect to putting devices into
- low power states, to be enforced (the ACPI 2.0 ordering
- of _PTS is used by default).
- nonvs prevents the kernel from saving/restoring the
- ACPI NVS memory during suspend/hibernation and resume.
- sci_force_enable causes the kernel to set SCI_EN directly
- on resume from S1/S3 (which is against the ACPI spec,
- but some broken systems don't work without it).
-
- acpi_use_timer_override [HW,ACPI]
- Use timer override. For some broken Nvidia NF5 boards
- that require a timer override, but don't have HPET
-
- add_efi_memmap [EFI; X86] Include EFI memory map in
- kernel's map of available physical RAM.
-
- agp= [AGP]
- { off | try_unsupported }
- off: disable AGP support
- try_unsupported: try to drive unsupported chipsets
- (may crash computer or cause data corruption)
-
- ALSA [HW,ALSA]
- See Documentation/sound/alsa/alsa-parameters.txt
-
- alignment= [KNL,ARM]
- Allow the default userspace alignment fault handler
- behaviour to be specified. Bit 0 enables warnings,
- bit 1 enables fixups, and bit 2 sends a segfault.
-
- align_va_addr= [X86-64]
- Align virtual addresses by clearing slice [14:12] when
- allocating a VMA at process creation time. This option
- gives you up to 3% performance improvement on AMD F15h
- machines (where it is enabled by default) for a
- CPU-intensive style benchmark, and it can vary highly in
- a microbenchmark depending on workload and compiler.
-
- 32: only for 32-bit processes
- 64: only for 64-bit processes
- on: enable for both 32- and 64-bit processes
- off: disable for both 32- and 64-bit processes
-
- alloc_snapshot [FTRACE]
- Allocate the ftrace snapshot buffer on boot up when the
- main buffer is allocated. This is handy if debugging
- and you need to use tracing_snapshot() on boot up, and
- do not want to use tracing_snapshot_alloc() as it needs
- to be done where GFP_KERNEL allocations are allowed.
-
- amd_iommu= [HW,X86-64]
- Pass parameters to the AMD IOMMU driver in the system.
- Possible values are:
- fullflush - enable flushing of IO/TLB entries when
- they are unmapped. Otherwise they are
- flushed before they will be reused, which
- is a lot of faster
- off - do not initialize any AMD IOMMU found in
- the system
- force_isolation - Force device isolation for all
- devices. The IOMMU driver is not
- allowed anymore to lift isolation
- requirements as needed. This option
- does not override iommu=pt
-
- amd_iommu_dump= [HW,X86-64]
- Enable AMD IOMMU driver option to dump the ACPI table
- for AMD IOMMU. With this option enabled, AMD IOMMU
- driver will print ACPI tables for AMD IOMMU during
- IOMMU initialization.
-
- amd_iommu_intr= [HW,X86-64]
- Specifies one of the following AMD IOMMU interrupt
- remapping modes:
- legacy - Use legacy interrupt remapping mode.
- vapic - Use virtual APIC mode, which allows IOMMU
- to inject interrupts directly into guest.
- This mode requires kvm-amd.avic=1.
- (Default when IOMMU HW support is present.)
-
- amijoy.map= [HW,JOY] Amiga joystick support
- Map of devices attached to JOY0DAT and JOY1DAT
- Format: <a>,<b>
- See also Documentation/input/joystick.txt
-
- analog.map= [HW,JOY] Analog joystick and gamepad support
- Specifies type or capabilities of an analog joystick
- connected to one of 16 gameports
- Format: <type1>,<type2>,..<type16>
-
- apc= [HW,SPARC]
- Power management functions (SPARCstation-4/5 + deriv.)
- Format: noidle
- Disable APC CPU standby support. SPARCstation-Fox does
- not play well with APC CPU idle - disable it if you have
- APC and your system crashes randomly.
-
- apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
- Change the output verbosity whilst booting
- Format: { quiet (default) | verbose | debug }
- Change the amount of debugging information output
- when initialising the APIC and IO-APIC components.
-
- apic_extnmi= [APIC,X86] External NMI delivery setting
- Format: { bsp (default) | all | none }
- bsp: External NMI is delivered only to CPU 0
- all: External NMIs are broadcast to all CPUs as a
- backup of CPU 0
- none: External NMI is masked for all CPUs. This is
- useful so that a dump capture kernel won't be
- shot down by NMI
-
- autoconf= [IPV6]
- See Documentation/networking/ipv6.txt.
-
- show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
- Limit apic dumping. The parameter defines the maximal
- number of local apics being dumped. Also it is possible
- to set it to "all" by meaning -- no limit here.
- Format: { 1 (default) | 2 | ... | all }.
- The parameter valid if only apic=debug or
- apic=verbose is specified.
- Example: apic=debug show_lapic=all
-
- apm= [APM] Advanced Power Management
- See header of arch/x86/kernel/apm_32.c.
-
- arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
- Format: <io>,<irq>,<nodeID>
-
- ataflop= [HW,M68k]
-
- atarimouse= [HW,MOUSE] Atari Mouse
-
- atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
- EzKey and similar keyboards
-
- atkbd.reset= [HW] Reset keyboard during initialization
-
- atkbd.set= [HW] Select keyboard code set
- Format: <int> (2 = AT (default), 3 = PS/2)
-
- atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
- keyboards
-
- atkbd.softraw= [HW] Choose between synthetic and real raw mode
- Format: <bool> (0 = real, 1 = synthetic (default))
-
- atkbd.softrepeat= [HW]
- Use software keyboard repeat
-
- audit= [KNL] Enable the audit sub-system
- Format: { "0" | "1" } (0 = disabled, 1 = enabled)
- 0 - kernel audit is disabled and can not be enabled
- until the next reboot
- unset - kernel audit is initialized but disabled and
- will be fully enabled by the userspace auditd.
- 1 - kernel audit is initialized and partially enabled,
- storing at most audit_backlog_limit messages in
- RAM until it is fully enabled by the userspace
- auditd.
- Default: unset
-
- audit_backlog_limit= [KNL] Set the audit queue size limit.
- Format: <int> (must be >=0)
- Default: 64
-
- bau= [X86_UV] Enable the BAU on SGI UV. The default
- behavior is to disable the BAU (i.e. bau=0).
- Format: { "0" | "1" }
- 0 - Disable the BAU.
- 1 - Enable the BAU.
- unset - Disable the BAU.
-
- baycom_epp= [HW,AX25]
- Format: <io>,<mode>
-
- baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
- Format: <io>,<mode>
- See header of drivers/net/hamradio/baycom_par.c.
-
- baycom_ser_fdx= [HW,AX25]
- BayCom Serial Port AX.25 Modem (Full Duplex Mode)
- Format: <io>,<irq>,<mode>[,<baud>]
- See header of drivers/net/hamradio/baycom_ser_fdx.c.
-
- baycom_ser_hdx= [HW,AX25]
- BayCom Serial Port AX.25 Modem (Half Duplex Mode)
- Format: <io>,<irq>,<mode>
- See header of drivers/net/hamradio/baycom_ser_hdx.c.
-
- blkdevparts= Manual partition parsing of block device(s) for
- embedded devices based on command line input.
- See Documentation/block/cmdline-partition.txt
-
- boot_delay= Milliseconds to delay each printk during boot.
- Values larger than 10 seconds (10000) are changed to
- no delay (0).
- Format: integer
-
- bootmem_debug [KNL] Enable bootmem allocator debug messages.
-
- bert_disable [ACPI]
- Disable BERT OS support on buggy BIOSes.
-
- bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
- bttv.radio= Most important insmod options are available as
- kernel args too.
- bttv.pll= See Documentation/video4linux/bttv/Insmod-options
- bttv.tuner=
-
- bulk_remove=off [PPC] This parameter disables the use of the pSeries
- firmware feature for flushing multiple hpte entries
- at a time.
-
- c101= [NET] Moxa C101 synchronous serial card
-
- cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
- Sometimes CPU hardware bugs make them report the cache
- size incorrectly. The kernel will attempt work arounds
- to fix known problems, but for some CPUs it is not
- possible to determine what the correct size should be.
- This option provides an override for these situations.
-
- ca_keys= [KEYS] This parameter identifies a specific key(s) on
- the system trusted keyring to be used for certificate
- trust validation.
- format: { id:<keyid> | builtin }
-
- cca= [MIPS] Override the kernel pages' cache coherency
- algorithm. Accepted values range from 0 to 7
- inclusive. See arch/mips/include/asm/pgtable-bits.h
- for platform specific values (SB1, Loongson3 and
- others).
-
- ccw_timeout_log [S390]
- See Documentation/s390/CommonIO for details.
-
- cgroup_disable= [KNL] Disable a particular controller
- Format: {name of the controller(s) to disable}
- The effects of cgroup_disable=foo are:
- - foo isn't auto-mounted if you mount all cgroups in
- a single hierarchy
- - foo isn't visible as an individually mountable
- subsystem
- {Currently only "memory" controller deal with this and
- cut the overhead, others just disable the usage. So
- only cgroup_disable=memory is actually worthy}
-
- cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1
- Format: { controller[,controller...] | "all" }
- Like cgroup_disable, but only applies to cgroup v1;
- the blacklisted controllers remain available in cgroup2.
-
- cgroup.memory= [KNL] Pass options to the cgroup memory controller.
- Format: <string>
- nosocket -- Disable socket memory accounting.
- nokmem -- Disable kernel memory accounting.
-
- checkreqprot [SELINUX] Set initial checkreqprot flag value.
- Format: { "0" | "1" }
- See security/selinux/Kconfig help text.
- 0 -- check protection applied by kernel (includes
- any implied execute protection).
- 1 -- check protection requested by application.
- Default value is set via a kernel config option.
- Value can be changed at runtime via
- /selinux/checkreqprot.
-
- cio_ignore= [S390]
- See Documentation/s390/CommonIO for details.
- clk_ignore_unused
- [CLK]
- Prevents the clock framework from automatically gating
- clocks that have not been explicitly enabled by a Linux
- device driver but are enabled in hardware at reset or
- by the bootloader/firmware. Note that this does not
- force such clocks to be always-on nor does it reserve
- those clocks in any way. This parameter is useful for
- debug and development, but should not be needed on a
- platform with proper driver support. For more
- information, see Documentation/clk.txt.
-
- clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
- [Deprecated]
- Forces specified clocksource (if available) to be used
- when calculating gettimeofday(). If specified
- clocksource is not available, it defaults to PIT.
- Format: { pit | tsc | cyclone | pmtmr }
-
- clocksource= Override the default clocksource
- Format: <string>
- Override the default clocksource and use the clocksource
- with the name specified.
- Some clocksource names to choose from, depending on
- the platform:
- [all] jiffies (this is the base, fallback clocksource)
- [ACPI] acpi_pm
- [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
- pxa_timer,timer3,32k_counter,timer0_1
- [AVR32] avr32
- [X86-32] pit,hpet,tsc;
- scx200_hrt on Geode; cyclone on IBM x440
- [MIPS] MIPS
- [PARISC] cr16
- [S390] tod
- [SH] SuperH
- [SPARC64] tick
- [X86-64] hpet,tsc
-
- clocksource.arm_arch_timer.evtstrm=
- [ARM,ARM64]
- Format: <bool>
- Enable/disable the eventstream feature of the ARM
- architected timer so that code using WFE-based polling
- loops can be debugged more effectively on production
- systems.
-
- clocksource.arm_arch_timer.fsl-a008585=
- [ARM64]
- Format: <bool>
- Enable/disable the workaround of Freescale/NXP
- erratum A-008585. This can be useful for KVM
- guests, if the guest device tree doesn't show the
- erratum. If unspecified, the workaround is
- enabled based on the device tree.
-
- clearcpuid=BITNUM [X86]
- Disable CPUID feature X for the kernel. See
- arch/x86/include/asm/cpufeatures.h for the valid bit
- numbers. Note the Linux specific bits are not necessarily
- stable over kernel options, but the vendor specific
- ones should be.
- Also note that user programs calling CPUID directly
- or using the feature without checking anything
- will still see it. This just prevents it from
- being used by the kernel or shown in /proc/cpuinfo.
- Also note the kernel might malfunction if you disable
- some critical bits.
-
- cma=nn[MG]@[start[MG][-end[MG]]]
- [ARM,X86,KNL]
- Sets the size of kernel global memory area for
- contiguous memory allocations and optionally the
- placement constraint by the physical address range of
- memory allocations. A value of 0 disables CMA
- altogether. For more information, see
- include/linux/dma-contiguous.h
-
- cmo_free_hint= [PPC] Format: { yes | no }
- Specify whether pages are marked as being inactive
- when they are freed. This is used in CMO environments
- to determine OS memory pressure for page stealing by
- a hypervisor.
- Default: yes
-
- coherent_pool=nn[KMG] [ARM,KNL]
- Sets the size of memory pool for coherent, atomic dma
- allocations, by default set to 256K.
-
- code_bytes [X86] How many bytes of object code to print
- in an oops report.
- Range: 0 - 8192
- Default: 64
-
- com20020= [HW,NET] ARCnet - COM20020 chipset
- Format:
- <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
-
- com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
- Format: <io>[,<irq>]
-
- com90xx= [HW,NET]
- ARCnet - COM90xx chipset (memory-mapped buffers)
- Format: <io>[,<irq>[,<memstart>]]
-
- condev= [HW,S390] console device
- conmode=
-
- console= [KNL] Output console device and options.
-
- tty<n> Use the virtual console device <n>.
-
- ttyS<n>[,options]
- ttyUSB0[,options]
- Use the specified serial port. The options are of
- the form "bbbbpnf", where "bbbb" is the baud rate,
- "p" is parity ("n", "o", or "e"), "n" is number of
- bits, and "f" is flow control ("r" for RTS or
- omit it). Default is "9600n8".
-
- See Documentation/serial-console.txt for more
- information. See
- Documentation/networking/netconsole.txt for an
- alternative.
-
- uart[8250],io,<addr>[,options]
- uart[8250],mmio,<addr>[,options]
- uart[8250],mmio16,<addr>[,options]
- uart[8250],mmio32,<addr>[,options]
- uart[8250],0x<addr>[,options]
- Start an early, polled-mode console on the 8250/16550
- UART at the specified I/O port or MMIO address,
- switching to the matching ttyS device later.
- MMIO inter-register address stride is either 8-bit
- (mmio), 16-bit (mmio16), or 32-bit (mmio32).
- If none of [io|mmio|mmio16|mmio32], <addr> is assumed
- to be equivalent to 'mmio'. 'options' are specified in
- the same format described for ttyS above; if unspecified,
- the h/w is not re-initialized.
-
- hvc<n> Use the hypervisor console device <n>. This is for
- both Xen and PowerPC hypervisors.
-
- If the device connected to the port is not a TTY but a braille
- device, prepend "brl," before the device type, for instance
- console=brl,ttyS0
- For now, only VisioBraille is supported.
-
- consoleblank= [KNL] The console blank (screen saver) timeout in
- seconds. Defaults to 10*60 = 10mins. A value of 0
- disables the blank timer.
-
- coredump_filter=
- [KNL] Change the default value for
- /proc/<pid>/coredump_filter.
- See also Documentation/filesystems/proc.txt.
-
- cpuidle.off=1 [CPU_IDLE]
- disable the cpuidle sub-system
-
- cpu_init_udelay=N
- [X86] Delay for N microsec between assert and de-assert
- of APIC INIT to start processors. This delay occurs
- on every CPU online, such as boot, and resume from suspend.
- Default: 10000
-
- cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
- Format:
- <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
-
- crashkernel=size[KMG][@offset[KMG]]
- [KNL] Using kexec, Linux can switch to a 'crash kernel'
- upon panic. This parameter reserves the physical
- memory region [offset, offset + size] for that kernel
- image. If '@offset' is omitted, then a suitable offset
- is selected automatically. Check
- Documentation/kdump/kdump.txt for further details.
-
- crashkernel=range1:size1[,range2:size2,...][@offset]
- [KNL] Same as above, but depends on the memory
- in the running system. The syntax of range is
- start-[end] where start and end are both
- a memory unit (amount[KMG]). See also
- Documentation/kdump/kdump.txt for an example.
-
- crashkernel=size[KMG],high
- [KNL, x86_64] range could be above 4G. Allow kernel
- to allocate physical memory region from top, so could
- be above 4G if system have more than 4G ram installed.
- Otherwise memory region will be allocated below 4G, if
- available.
- It will be ignored if crashkernel=X is specified.
- crashkernel=size[KMG],low
- [KNL, x86_64] range under 4G. When crashkernel=X,high
- is passed, kernel could allocate physical memory region
- above 4G, that cause second kernel crash on system
- that require some amount of low memory, e.g. swiotlb
- requires at least 64M+32K low memory, also enough extra
- low memory is needed to make sure DMA buffers for 32-bit
- devices won't run out. Kernel would try to allocate at
- at least 256M below 4G automatically.
- This one let user to specify own low range under 4G
- for second kernel instead.
- 0: to disable low allocation.
- It will be ignored when crashkernel=X,high is not used
- or memory reserved is below 4G.
-
- cryptomgr.notests
- [KNL] Disable crypto self-tests
-
- cs89x0_dma= [HW,NET]
- Format: <dma>
-
- cs89x0_media= [HW,NET]
- Format: { rj45 | aui | bnc }
-
- dasd= [HW,NET]
- See header of drivers/s390/block/dasd_devmap.c.
-
- db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
- (one device per port)
- Format: <port#>,<type>
- See also Documentation/input/joystick-parport.txt
-
- ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
- time. See Documentation/dynamic-debug-howto.txt for
- details. Deprecated, see dyndbg.
-
- debug [KNL] Enable kernel debugging (events log level).
-
- debug_locks_verbose=
- [KNL] verbose self-tests
- Format=<0|1>
- Print debugging info while doing the locking API
- self-tests.
- We default to 0 (no extra messages), setting it to
- 1 will print _a lot_ more information - normally
- only useful to kernel developers.
-
- debug_objects [KNL] Enable object debugging
-
- no_debug_objects
- [KNL] Disable object debugging
-
- debug_guardpage_minorder=
- [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
- parameter allows control of the order of pages that will
- be intentionally kept free (and hence protected) by the
- buddy allocator. Bigger value increase the probability
- of catching random memory corruption, but reduce the
- amount of memory for normal system use. The maximum
- possible value is MAX_ORDER/2. Setting this parameter
- to 1 or 2 should be enough to identify most random
- memory corruption problems caused by bugs in kernel or
- driver code when a CPU writes to (or reads from) a
- random memory location. Note that there exists a class
- of memory corruptions problems caused by buggy H/W or
- F/W or by drivers badly programing DMA (basically when
- memory is written at bus level and the CPU MMU is
- bypassed) which are not detectable by
- CONFIG_DEBUG_PAGEALLOC, hence this option will not help
- tracking down these problems.
-
- debug_pagealloc=
- [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
- parameter enables the feature at boot time. In
- default, it is disabled. We can avoid allocating huge
- chunk of memory for debug pagealloc if we don't enable
- it at boot time and the system will work mostly same
- with the kernel built without CONFIG_DEBUG_PAGEALLOC.
- on: enable the feature
-
- debugpat [X86] Enable PAT debugging
-
- decnet.addr= [HW,NET]
- Format: <area>[,<node>]
- See also Documentation/networking/decnet.txt.
-
- default_hugepagesz=
- [same as hugepagesz=] The size of the default
- HugeTLB page size. This is the size represented by
- the legacy /proc/ hugepages APIs, used for SHM, and
- default size when mounting hugetlbfs filesystems.
- Defaults to the default architecture's huge page size
- if not specified.
-
- dhash_entries= [KNL]
- Set number of hash buckets for dentry cache.
-
- disable_1tb_segments [PPC]
- Disables the use of 1TB hash page table segments. This
- causes the kernel to fall back to 256MB segments which
- can be useful when debugging issues that require an SLB
- miss to occur.
-
- disable= [IPV6]
- See Documentation/networking/ipv6.txt.
-
- disable_radix [PPC]
- Disable RADIX MMU mode on POWER9
-
- disable_cpu_apicid= [X86,APIC,SMP]
- Format: <int>
- The number of initial APIC ID for the
- corresponding CPU to be disabled at boot,
- mostly used for the kdump 2nd kernel to
- disable BSP to wake up multiple CPUs without
- causing system reset or hang due to sending
- INIT from AP to BSP.
-
- disable_ddw [PPC/PSERIES]
- Disable Dynamic DMA Window support. Use this if
- to workaround buggy firmware.
-
- disable_ipv6= [IPV6]
- See Documentation/networking/ipv6.txt.
-
- disable_mtrr_cleanup [X86]
- The kernel tries to adjust MTRR layout from continuous
- to discrete, to make X server driver able to add WB
- entry later. This parameter disables that.
-
- disable_mtrr_trim [X86, Intel and AMD only]
- By default the kernel will trim any uncacheable
- memory out of your available memory pool based on
- MTRR settings. This parameter disables that behavior,
- possibly causing your machine to run very slowly.
-
- disable_timer_pin_1 [X86]
- Disable PIN 1 of APIC timer
- Can be useful to work around chipset bugs.
-
- dis_ucode_ldr [X86] Disable the microcode loader.
-
- dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
- this option disables the debugging code at boot.
-
- dma_debug_entries=<number>
- This option allows to tune the number of preallocated
- entries for DMA-API debugging code. One entry is
- required per DMA-API allocation. Use this if the
- DMA-API debugging code disables itself because the
- architectural default is too low.
-
- dma_debug_driver=<driver_name>
- With this option the DMA-API debugging driver
- filter feature can be enabled at boot time. Just
- pass the driver to filter for as the parameter.
- The filter can be disabled or changed to another
- driver later using sysfs.
-
- drm_kms_helper.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
- Broken monitors, graphic adapters, KVMs and EDIDless
- panels may send no or incorrect EDID data sets.
- This parameter allows to specify an EDID data sets
- in the /lib/firmware directory that are used instead.
- Generic built-in EDID data sets are used, if one of
- edid/1024x768.bin, edid/1280x1024.bin,
- edid/1680x1050.bin, or edid/1920x1080.bin is given
- and no file with the same name exists. Details and
- instructions how to build your own EDID data are
- available in Documentation/EDID/HOWTO.txt. An EDID
- data set will only be used for a particular connector,
- if its name and a colon are prepended to the EDID
- name. Each connector may use a unique EDID data
- set by separating the files with a comma. An EDID
- data set with no connector name will be used for
- any connectors not explicitly specified.
-
- dscc4.setup= [NET]
-
- dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
- module.dyndbg[="val"]
- Enable debug messages at boot time. See
- Documentation/dynamic-debug-howto.txt for details.
-
- nompx [X86] Disables Intel Memory Protection Extensions.
- See Documentation/x86/intel_mpx.txt for more
- information about the feature.
-
- nopku [X86] Disable Memory Protection Keys CPU feature found
- in some Intel CPUs.
-
- eagerfpu= [X86]
- on enable eager fpu restore
- off disable eager fpu restore
- auto selects the default scheme, which automatically
- enables eagerfpu restore for xsaveopt.
-
- module.async_probe [KNL]
- Enable asynchronous probe on this module.
-
- early_ioremap_debug [KNL]
- Enable debug messages in early_ioremap support. This
- is useful for tracking down temporary early mappings
- which are not unmapped.
-
- earlycon= [KNL] Output early console device and options.
-
- When used with no options, the early console is
- determined by the stdout-path property in device
- tree's chosen node.
-
- cdns,<addr>[,options]
- Start an early, polled-mode console on a Cadence
- (xuartps) serial port at the specified address. Only
- supported option is baud rate. If baud rate is not
- specified, the serial port must already be setup and
- configured.
-
- uart[8250],io,<addr>[,options]
- uart[8250],mmio,<addr>[,options]
- uart[8250],mmio32,<addr>[,options]
- uart[8250],mmio32be,<addr>[,options]
- uart[8250],0x<addr>[,options]
- Start an early, polled-mode console on the 8250/16550
- UART at the specified I/O port or MMIO address.
- MMIO inter-register address stride is either 8-bit
- (mmio) or 32-bit (mmio32 or mmio32be).
- If none of [io|mmio|mmio32|mmio32be], <addr> is assumed
- to be equivalent to 'mmio'. 'options' are specified
- in the same format described for "console=ttyS<n>"; if
- unspecified, the h/w is not initialized.
-
- pl011,<addr>
- pl011,mmio32,<addr>
- Start an early, polled-mode console on a pl011 serial
- port at the specified address. The pl011 serial port
- must already be setup and configured. Options are not
- yet supported. If 'mmio32' is specified, then only
- the driver will use only 32-bit accessors to read/write
- the device registers.
-
- meson,<addr>
- Start an early, polled-mode console on a meson serial
- port at the specified address. The serial port must
- already be setup and configured. Options are not yet
- supported.
-
- msm_serial,<addr>
- Start an early, polled-mode console on an msm serial
- port at the specified address. The serial port
- must already be setup and configured. Options are not
- yet supported.
-
- msm_serial_dm,<addr>
- Start an early, polled-mode console on an msm serial
- dm port at the specified address. The serial port
- must already be setup and configured. Options are not
- yet supported.
-
- smh Use ARM semihosting calls for early console.
-
- s3c2410,<addr>
- s3c2412,<addr>
- s3c2440,<addr>
- s3c6400,<addr>
- s5pv210,<addr>
- exynos4210,<addr>
- Use early console provided by serial driver available
- on Samsung SoCs, requires selecting proper type and
- a correct base address of the selected UART port. The
- serial port must already be setup and configured.
- Options are not yet supported.
-
- lpuart,<addr>
- lpuart32,<addr>
- Use early console provided by Freescale LP UART driver
- found on Freescale Vybrid and QorIQ LS1021A processors.
- A valid base address must be provided, and the serial
- port must already be setup and configured.
-
- armada3700_uart,<addr>
- Start an early, polled-mode console on the
- Armada 3700 serial port at the specified
- address. The serial port must already be setup
- and configured. Options are not yet supported.
-
- earlyprintk= [X86,SH,BLACKFIN,ARM,M68k]
- earlyprintk=vga
- earlyprintk=efi
- earlyprintk=xen
- earlyprintk=serial[,ttySn[,baudrate]]
- earlyprintk=serial[,0x...[,baudrate]]
- earlyprintk=ttySn[,baudrate]
- earlyprintk=dbgp[debugController#]
- earlyprintk=pciserial,bus:device.function[,baudrate]
-
- earlyprintk is useful when the kernel crashes before
- the normal console is initialized. It is not enabled by
- default because it has some cosmetic problems.
-
- Append ",keep" to not disable it when the real console
- takes over.
-
- Only one of vga, efi, serial, or usb debug port can
- be used at a time.
-
- Currently only ttyS0 and ttyS1 may be specified by
- name. Other I/O ports may be explicitly specified
- on some architectures (x86 and arm at least) by
- replacing ttySn with an I/O port address, like this:
- earlyprintk=serial,0x1008,115200
- You can find the port for a given device in
- /proc/tty/driver/serial:
- 2: uart:ST16650V2 port:00001008 irq:18 ...
-
- Interaction with the standard serial driver is not
- very good.
-
- The VGA and EFI output is eventually overwritten by
- the real console.
-
- The xen output can only be used by Xen PV guests.
-
- edac_report= [HW,EDAC] Control how to report EDAC event
- Format: {"on" | "off" | "force"}
- on: enable EDAC to report H/W event. May be overridden
- by other higher priority error reporting module.
- off: disable H/W event reporting through EDAC.
- force: enforce the use of EDAC to report H/W event.
- default: on.
-
- ekgdboc= [X86,KGDB] Allow early kernel console debugging
- ekgdboc=kbd
-
- This is designed to be used in conjunction with
- the boot argument: earlyprintk=vga
-
- edd= [EDD]
- Format: {"off" | "on" | "skip[mbr]"}
-
- efi= [EFI]
- Format: { "old_map", "nochunk", "noruntime", "debug" }
- old_map [X86-64]: switch to the old ioremap-based EFI
- runtime services mapping. 32-bit still uses this one by
- default.
- nochunk: disable reading files in "chunks" in the EFI
- boot stub, as chunking can cause problems with some
- firmware implementations.
- noruntime : disable EFI runtime services support
- debug: enable misc debug output
-
- efi_no_storage_paranoia [EFI; X86]
- Using this parameter you can use more than 50% of
- your efi variable storage. Use this parameter only if
- you are really sure that your UEFI does sane gc and
- fulfills the spec otherwise your board may brick.
-
- efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI; X86]
- Add arbitrary attribute to specific memory range by
- updating original EFI memory map.
- Region of memory which aa attribute is added to is
- from ss to ss+nn.
- If efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000
- is specified, EFI_MEMORY_MORE_RELIABLE(0x10000)
- attribute is added to range 0x100000000-0x180000000 and
- 0x10a0000000-0x1120000000.
-
- Using this parameter you can do debugging of EFI memmap
- related feature. For example, you can do debugging of
- Address Range Mirroring feature even if your box
- doesn't support it.
-
- efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT
- that is to be dynamically loaded by Linux. If there are
- multiple variables with the same name but with different
- vendor GUIDs, all of them will be loaded. See
- Documentation/acpi/ssdt-overlays.txt for details.
-
-
- eisa_irq_edge= [PARISC,HW]
- See header of drivers/parisc/eisa.c.
-
- elanfreq= [X86-32]
- See comment before function elanfreq_setup() in
- arch/x86/kernel/cpu/cpufreq/elanfreq.c.
-
- elevator= [IOSCHED]
- Format: {"cfq" | "deadline" | "noop"}
- See Documentation/block/cfq-iosched.txt and
- Documentation/block/deadline-iosched.txt for details.
-
- elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
- Specifies physical address of start of kernel core
- image elf header and optionally the size. Generally
- kexec loader will pass this option to capture kernel.
- See Documentation/kdump/kdump.txt for details.
-
- enable_mtrr_cleanup [X86]
- The kernel tries to adjust MTRR layout from continuous
- to discrete, to make X server driver able to add WB
- entry later. This parameter enables that.
-
- enable_timer_pin_1 [X86]
- Enable PIN 1 of APIC timer
- Can be useful to work around chipset bugs
- (in particular on some ATI chipsets).
- The kernel tries to set a reasonable default.
-
- enforcing [SELINUX] Set initial enforcing status.
- Format: {"0" | "1"}
- See security/selinux/Kconfig help text.
- 0 -- permissive (log only, no denials).
- 1 -- enforcing (deny and log).
- Default value is 0.
- Value can be changed at runtime via /selinux/enforce.
-
- erst_disable [ACPI]
- Disable Error Record Serialization Table (ERST)
- support.
-
- ether= [HW,NET] Ethernet cards parameters
- This option is obsoleted by the "netdev=" option, which
- has equivalent usage. See its documentation for details.
-
- evm= [EVM]
- Format: { "fix" }
- Permit 'security.evm' to be updated regardless of
- current integrity status.
-
- failslab=
- fail_page_alloc=
- fail_make_request=[KNL]
- General fault injection mechanism.
- Format: <interval>,<probability>,<space>,<times>
- See also Documentation/fault-injection/.
-
- floppy= [HW]
- See Documentation/blockdev/floppy.txt.
-
- force_pal_cache_flush
- [IA-64] Avoid check_sal_cache_flush which may hang on
- buggy SAL_CACHE_FLUSH implementations. Using this
- parameter will force ia64_sal_cache_flush to call
- ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
-
- forcepae [X86-32]
- Forcefully enable Physical Address Extension (PAE).
- Many Pentium M systems disable PAE but may have a
- functionally usable PAE implementation.
- Warning: use of this parameter will taint the kernel
- and may cause unknown problems.
-
- ftrace=[tracer]
- [FTRACE] will set and start the specified tracer
- as early as possible in order to facilitate early
- boot debugging.
-
- ftrace_dump_on_oops[=orig_cpu]
- [FTRACE] will dump the trace buffers on oops.
- If no parameter is passed, ftrace will dump
- buffers of all CPUs, but if you pass orig_cpu, it will
- dump only the buffer of the CPU that triggered the
- oops.
-
- ftrace_filter=[function-list]
- [FTRACE] Limit the functions traced by the function
- tracer at boot up. function-list is a comma separated
- list of functions. This list can be changed at run
- time by the set_ftrace_filter file in the debugfs
- tracing directory.
-
- ftrace_notrace=[function-list]
- [FTRACE] Do not trace the functions specified in
- function-list. This list can be changed at run time
- by the set_ftrace_notrace file in the debugfs
- tracing directory.
-
- ftrace_graph_filter=[function-list]
- [FTRACE] Limit the top level callers functions traced
- by the function graph tracer at boot up.
- function-list is a comma separated list of functions
- that can be changed at run time by the
- set_graph_function file in the debugfs tracing directory.
-
- ftrace_graph_notrace=[function-list]
- [FTRACE] Do not trace from the functions specified in
- function-list. This list is a comma separated list of
- functions that can be changed at run time by the
- set_graph_notrace file in the debugfs tracing directory.
-
- gamecon.map[2|3]=
- [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
- support via parallel port (up to 5 devices per port)
- Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
- See also Documentation/input/joystick-parport.txt
-
- gamma= [HW,DRM]
-
- gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
- Format: off | on
- default: on
-
- gcov_persist= [GCOV] When non-zero (default), profiling data for
- kernel modules is saved and remains accessible via
- debugfs, even when the module is unloaded/reloaded.
- When zero, profiling data is discarded and associated
- debugfs files are removed at module unload time.
-
- gpt [EFI] Forces disk with valid GPT signature but
- invalid Protective MBR to be treated as GPT. If the
- primary GPT is corrupted, it enables the backup/alternate
- GPT to be used instead.
-
- grcan.enable0= [HW] Configuration of physical interface 0. Determines
- the "Enable 0" bit of the configuration register.
- Format: 0 | 1
- Default: 0
- grcan.enable1= [HW] Configuration of physical interface 1. Determines
- the "Enable 0" bit of the configuration register.
- Format: 0 | 1
- Default: 0
- grcan.select= [HW] Select which physical interface to use.
- Format: 0 | 1
- Default: 0
- grcan.txsize= [HW] Sets the size of the tx buffer.
- Format: <unsigned int> such that (txsize & ~0x1fffc0) == 0.
- Default: 1024
- grcan.rxsize= [HW] Sets the size of the rx buffer.
- Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
- Default: 1024
-
- gpio-mockup.gpio_mockup_ranges
- [HW] Sets the ranges of gpiochip of for this device.
- Format: <start1>,<end1>,<start2>,<end2>...
-
- hardlockup_all_cpu_backtrace=
- [KNL] Should the hard-lockup detector generate
- backtraces on all cpus.
- Format: <integer>
-
- hashdist= [KNL,NUMA] Large hashes allocated during boot
- are distributed across NUMA nodes. Defaults on
- for 64-bit NUMA, off otherwise.
- Format: 0 | 1 (for off | on)
-
- hcl= [IA-64] SGI's Hardware Graph compatibility layer
-
- hd= [EIDE] (E)IDE hard drive subsystem geometry
- Format: <cyl>,<head>,<sect>
-
- hest_disable [ACPI]
- Disable Hardware Error Source Table (HEST) support;
- corresponding firmware-first mode error processing
- logic will be disabled.
-
- highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
- size of <nn>. This works even on boxes that have no
- highmem otherwise. This also works to reduce highmem
- size on bigger boxes.
-
- highres= [KNL] Enable/disable high resolution timer mode.
- Valid parameters: "on", "off"
- Default: "on"
-
- hisax= [HW,ISDN]
- See Documentation/isdn/README.HiSax.
-
- hlt [BUGS=ARM,SH]
-
- hpet= [X86-32,HPET] option to control HPET usage
- Format: { enable (default) | disable | force |
- verbose }
- disable: disable HPET and use PIT instead
- force: allow force enabled of undocumented chips (ICH4,
- VIA, nVidia)
- verbose: show contents of HPET registers during setup
-
- hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET
- registers. Default set by CONFIG_HPET_MMAP_DEFAULT.
-
- hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
- hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
- On x86-64 and powerpc, this option can be specified
- multiple times interleaved with hugepages= to reserve
- huge pages of different sizes. Valid pages sizes on
- x86-64 are 2M (when the CPU supports "pse") and 1G
- (when the CPU supports the "pdpe1gb" cpuinfo flag).
-
- hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
- terminal devices. Valid values: 0..8
- hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
- If specified, z/VM IUCV HVC accepts connections
- from listed z/VM user IDs only.
-
- hwthread_map= [METAG] Comma-separated list of Linux cpu id to
- hardware thread id mappings.
- Format: <cpu>:<hwthread>
-
- keep_bootcon [KNL]
- Do not unregister boot console at start. This is only
- useful for debugging when something happens in the window
- between unregistering the boot console and initializing
- the real console.
-
- i2c_bus= [HW] Override the default board specific I2C bus speed
- or register an additional I2C bus that is not
- registered from board initialization code.
- Format:
- <bus_id>,<clkrate>
-
- i8042.debug [HW] Toggle i8042 debug mode
- i8042.unmask_kbd_data
- [HW] Enable printing of interrupt data from the KBD port
- (disabled by default, and as a pre-condition
- requires that i8042.debug=1 be enabled)
- i8042.direct [HW] Put keyboard port into non-translated mode
- i8042.dumbkbd [HW] Pretend that controller can only read data from
- keyboard and cannot control its state
- (Don't attempt to blink the leds)
- i8042.noaux [HW] Don't check for auxiliary (== mouse) port
- i8042.nokbd [HW] Don't check/create keyboard port
- i8042.noloop [HW] Disable the AUX Loopback command while probing
- for the AUX port
- i8042.nomux [HW] Don't check presence of an active multiplexing
- controller
- i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
- controllers
- i8042.notimeout [HW] Ignore timeout condition signalled by controller
- i8042.reset [HW] Reset the controller during init, cleanup and
- suspend-to-ram transitions, only during s2r
- transitions, or never reset
- Format: { 1 | Y | y | 0 | N | n }
- 1, Y, y: always reset controller
- 0, N, n: don't ever reset controller
- Default: only on s2r transitions on x86; most other
- architectures force reset to be always executed
- i8042.unlock [HW] Unlock (ignore) the keylock
- i8042.kbdreset [HW] Reset device connected to KBD port
-
- i810= [HW,DRM]
-
- i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
- indicates that the driver is running on unsupported
- hardware.
- i8k.force [HW] Activate i8k driver even if SMM BIOS signature
- does not match list of supported models.
- i8k.power_status
- [HW] Report power status in /proc/i8k
- (disabled by default)
- i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
- capability is set.
-
- i915.invert_brightness=
- [DRM] Invert the sense of the variable that is used to
- set the brightness of the panel backlight. Normally a
- brightness value of 0 indicates backlight switched off,
- and the maximum of the brightness value sets the backlight
- to maximum brightness. If this parameter is set to 0
- (default) and the machine requires it, or this parameter
- is set to 1, a brightness value of 0 sets the backlight
- to maximum brightness, and the maximum of the brightness
- value switches the backlight off.
- -1 -- never invert brightness
- 0 -- machine default
- 1 -- force brightness inversion
-
- icn= [HW,ISDN]
- Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
-
- ide-core.nodma= [HW] (E)IDE subsystem
- Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
- .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
- .cdrom .chs .ignore_cable are additional options
- See Documentation/ide/ide.txt.
-
- ide-generic.probe-mask= [HW] (E)IDE subsystem
- Format: <int>
- Probe mask for legacy ISA IDE ports. Depending on
- platform up to 6 ports are supported, enabled by
- setting corresponding bits in the mask to 1. The
- default value is 0x0, which has a special meaning.
- On systems that have PCI, it triggers scanning the
- PCI bus for the first and the second port, which
- are then probed. On systems without PCI the value
- of 0x0 enables probing the two first ports as if it
- was 0x3.
-
- ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
- Claim all unknown PCI IDE storage controllers.
-
- idle= [X86]
- Format: idle=poll, idle=halt, idle=nomwait
- Poll forces a polling idle loop that can slightly
- improve the performance of waking up a idle CPU, but
- will use a lot of power and make the system run hot.
- Not recommended.
- idle=halt: Halt is forced to be used for CPU idle.
- In such case C2/C3 won't be used again.
- idle=nomwait: Disable mwait for CPU C-states
-
- ieee754= [MIPS] Select IEEE Std 754 conformance mode
- Format: { strict | legacy | 2008 | relaxed }
- Default: strict
-
- Choose which programs will be accepted for execution
- based on the IEEE 754 NaN encoding(s) supported by
- the FPU and the NaN encoding requested with the value
- of an ELF file header flag individually set by each
- binary. Hardware implementations are permitted to
- support either or both of the legacy and the 2008 NaN
- encoding mode.
-
- Available settings are as follows:
- strict accept binaries that request a NaN encoding
- supported by the FPU
- legacy only accept legacy-NaN binaries, if supported
- by the FPU
- 2008 only accept 2008-NaN binaries, if supported
- by the FPU
- relaxed accept any binaries regardless of whether
- supported by the FPU
-
- The FPU emulator is always able to support both NaN
- encodings, so if no FPU hardware is present or it has
- been disabled with 'nofpu', then the settings of
- 'legacy' and '2008' strap the emulator accordingly,
- 'relaxed' straps the emulator for both legacy-NaN and
- 2008-NaN, whereas 'strict' enables legacy-NaN only on
- legacy processors and both NaN encodings on MIPS32 or
- MIPS64 CPUs.
-
- The setting for ABS.fmt/NEG.fmt instruction execution
- mode generally follows that for the NaN encoding,
- except where unsupported by hardware.
-
- ignore_loglevel [KNL]
- Ignore loglevel setting - this will print /all/
- kernel messages to the console. Useful for debugging.
- We also add it as printk module parameter, so users
- could change it dynamically, usually by
- /sys/module/printk/parameters/ignore_loglevel.
-
- ignore_rlimit_data
- Ignore RLIMIT_DATA setting for data mappings,
- print warning at first misuse. Can be changed via
- /sys/module/kernel/parameters/ignore_rlimit_data.
-
- ihash_entries= [KNL]
- Set number of hash buckets for inode cache.
-
- ima_appraise= [IMA] appraise integrity measurements
- Format: { "off" | "enforce" | "fix" | "log" }
- default: "enforce"
-
- ima_appraise_tcb [IMA]
- The builtin appraise policy appraises all files
- owned by uid=0.
-
- ima_hash= [IMA]
- Format: { md5 | sha1 | rmd160 | sha256 | sha384
- | sha512 | ... }
- default: "sha1"
-
- The list of supported hash algorithms is defined
- in crypto/hash_info.h.
-
- ima_policy= [IMA]
- The builtin measurement policy to load during IMA
- setup. Specyfing "tcb" as the value, measures all
- programs exec'd, files mmap'd for exec, and all files
- opened with the read mode bit set by either the
- effective uid (euid=0) or uid=0.
- Format: "tcb"
-
- ima_tcb [IMA] Deprecated. Use ima_policy= instead.
- Load a policy which meets the needs of the Trusted
- Computing Base. This means IMA will measure all
- programs exec'd, files mmap'd for exec, and all files
- opened for read by uid=0.
-
- ima_template= [IMA]
- Select one of defined IMA measurements template formats.
- Formats: { "ima" | "ima-ng" | "ima-sig" }
- Default: "ima-ng"
-
- ima_template_fmt=
- [IMA] Define a custom template format.
- Format: { "field1|...|fieldN" }
-
- ima.ahash_minsize= [IMA] Minimum file size for asynchronous hash usage
- Format: <min_file_size>
- Set the minimal file size for using asynchronous hash.
- If left unspecified, ahash usage is disabled.
-
- ahash performance varies for different data sizes on
- different crypto accelerators. This option can be used
- to achieve the best performance for a particular HW.
-
- ima.ahash_bufsize= [IMA] Asynchronous hash buffer size
- Format: <bufsize>
- Set hashing buffer size. Default: 4k.
-
- ahash performance varies for different chunk sizes on
- different crypto accelerators. This option can be used
- to achieve best performance for particular HW.
-
- init= [KNL]
- Format: <full_path>
- Run specified binary instead of /sbin/init as init
- process.
-
- initcall_debug [KNL] Trace initcalls as they are executed. Useful
- for working out where the kernel is dying during
- startup.
-
- initcall_blacklist= [KNL] Do not execute a comma-separated list of
- initcall functions. Useful for debugging built-in
- modules and initcalls.
-
- initrd= [BOOT] Specify the location of the initial ramdisk
-
- init_pkru= [x86] Specify the default memory protection keys rights
- register contents for all processes. 0x55555554 by
- default (disallow access to all but pkey 0). Can
- override in debugfs after boot.
-
- inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
- Format: <irq>
-
- int_pln_enable [x86] Enable power limit notification interrupt
-
- integrity_audit=[IMA]
- Format: { "0" | "1" }
- 0 -- basic integrity auditing messages. (Default)
- 1 -- additional integrity auditing messages.
-
- intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
- on
- Enable intel iommu driver.
- off
- Disable intel iommu driver.
- igfx_off [Default Off]
- By default, gfx is mapped as normal device. If a gfx
- device has a dedicated DMAR unit, the DMAR unit is
- bypassed by not enabling DMAR with this option. In
- this case, gfx device will use physical address for
- DMA.
- forcedac [x86_64]
- With this option iommu will not optimize to look
- for io virtual address below 32-bit forcing dual
- address cycle on pci bus for cards supporting greater
- than 32-bit addressing. The default is to look
- for translation below 32-bit and if not available
- then look in the higher range.
- strict [Default Off]
- With this option on every unmap_single operation will
- result in a hardware IOTLB flush operation as opposed
- to batching them for performance.
- sp_off [Default Off]
- By default, super page will be supported if Intel IOMMU
- has the capability. With this option, super page will
- not be supported.
- ecs_off [Default Off]
- By default, extended context tables will be supported if
- the hardware advertises that it has support both for the
- extended tables themselves, and also PASID support. With
- this option set, extended tables will not be used even
- on hardware which claims to support them.
-
- intel_idle.max_cstate= [KNL,HW,ACPI,X86]
- 0 disables intel_idle and fall back on acpi_idle.
- 1 to 9 specify maximum depth of C-state.
-
- intel_pstate= [X86]
- disable
- Do not enable intel_pstate as the default
- scaling driver for the supported processors
- force
- Enable intel_pstate on systems that prohibit it by default
- in favor of acpi-cpufreq. Forcing the intel_pstate driver
- instead of acpi-cpufreq may disable platform features, such
- as thermal controls and power capping, that rely on ACPI
- P-States information being indicated to OSPM and therefore
- should be used with caution. This option does not work with
- processors that aren't supported by the intel_pstate driver
- or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
- no_hwp
- Do not enable hardware P state control (HWP)
- if available.
- hwp_only
- Only load intel_pstate on systems which support
- hardware P state control (HWP) if available.
- support_acpi_ppc
- Enforce ACPI _PPC performance limits. If the Fixed ACPI
- Description Table, specifies preferred power management
- profile as "Enterprise Server" or "Performance Server",
- then this feature is turned on by default.
-
- intremap= [X86-64, Intel-IOMMU]
- on enable Interrupt Remapping (default)
- off disable Interrupt Remapping
- nosid disable Source ID checking
- no_x2apic_optout
- BIOS x2APIC opt-out request will be ignored
- nopost disable Interrupt Posting
-
- iomem= Disable strict checking of access to MMIO memory
- strict regions from userspace.
- relaxed
-
- iommu= [x86]
- off
- force
- noforce
- biomerge
- panic
- nopanic
- merge
- nomerge
- forcesac
- soft
- pt [x86, IA-64]
- nobypass [PPC/POWERNV]
- Disable IOMMU bypass, using IOMMU for PCI devices.
-
-
- io7= [HW] IO7 for Marvel based alpha systems
- See comment before marvel_specify_io7 in
- arch/alpha/kernel/core_marvel.c.
-
- io_delay= [X86] I/O delay method
- 0x80
- Standard port 0x80 based delay
- 0xed
- Alternate port 0xed based delay (needed on some systems)
- udelay
- Simple two microseconds delay
- none
- No delay
-
- ip= [IP_PNP]
- See Documentation/filesystems/nfs/nfsroot.txt.
-
- irqaffinity= [SMP] Set the default irq affinity mask
- The argument is a cpu list, as described above.
-
- irqfixup [HW]
- When an interrupt is not handled search all handlers
- for it. Intended to get systems with badly broken
- firmware running.
-
- irqpoll [HW]
- When an interrupt is not handled search all handlers
- for it. Also check all handlers each timer
- interrupt. Intended to get systems with badly broken
- firmware running.
-
- isapnp= [ISAPNP]
- Format: <RDP>,<reset>,<pci_scan>,<verbosity>
-
- isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
- The argument is a cpu list, as described above.
-
- This option can be used to specify one or more CPUs
- to isolate from the general SMP balancing and scheduling
- algorithms. You can move a process onto or off an
- "isolated" CPU via the CPU affinity syscalls or cpuset.
- <cpu number> begins at 0 and the maximum value is
- "number of CPUs in system - 1".
-
- This option is the preferred way to isolate CPUs. The
- alternative -- manually setting the CPU mask of all
- tasks in the system -- can cause problems and
- suboptimal load balancer performance.
-
- iucv= [HW,NET]
-
- ivrs_ioapic [HW,X86_64]
- Provide an override to the IOAPIC-ID<->DEVICE-ID
- mapping provided in the IVRS ACPI table. For
- example, to map IOAPIC-ID decimal 10 to
- PCI device 00:14.0 write the parameter as:
- ivrs_ioapic[10]=00:14.0
-
- ivrs_hpet [HW,X86_64]
- Provide an override to the HPET-ID<->DEVICE-ID
- mapping provided in the IVRS ACPI table. For
- example, to map HPET-ID decimal 0 to
- PCI device 00:14.0 write the parameter as:
- ivrs_hpet[0]=00:14.0
-
- ivrs_acpihid [HW,X86_64]
- Provide an override to the ACPI-HID:UID<->DEVICE-ID
- mapping provided in the IVRS ACPI table. For
- example, to map UART-HID:UID AMD0020:0 to
- PCI device 00:14.5 write the parameter as:
- ivrs_acpihid[00:14.5]=AMD0020:0
-
- js= [HW,JOY] Analog joystick
- See Documentation/input/joystick.txt.
-
- nokaslr [KNL]
- When CONFIG_RANDOMIZE_BASE is set, this disables
- kernel and module base offset ASLR (Address Space
- Layout Randomization).
-
- keepinitrd [HW,ARM]
-
- kernelcore= [KNL,X86,IA-64,PPC]
- Format: nn[KMGTPE] | "mirror"
- This parameter
- specifies the amount of memory usable by the kernel
- for non-movable allocations. The requested amount is
- spread evenly throughout all nodes in the system. The
- remaining memory in each node is used for Movable
- pages. In the event, a node is too small to have both
- kernelcore and Movable pages, kernelcore pages will
- take priority and other nodes will have a larger number
- of Movable pages. The Movable zone is used for the
- allocation of pages that may be reclaimed or moved
- by the page migration subsystem. This means that
- HugeTLB pages may not be allocated from this zone.
- Note that allocations like PTEs-from-HighMem still
- use the HighMem zone if it exists, and the Normal
- zone if it does not.
-
- Instead of specifying the amount of memory (nn[KMGTPE]),
- you can specify "mirror" option. In case "mirror"
- option is specified, mirrored (reliable) memory is used
- for non-movable allocations and remaining memory is used
- for Movable pages. nn[KMGTPE] and "mirror" are exclusive,
- so you can NOT specify nn[KMGTPE] and "mirror" at the same
- time.
-
- kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
- Format: <Controller#>[,poll interval]
- The controller # is the number of the ehci usb debug
- port as it is probed via PCI. The poll interval is
- optional and is the number seconds in between
- each poll cycle to the debug port in case you need
- the functionality for interrupting the kernel with
- gdb or control-c on the dbgp connection. When
- not using this parameter you use sysrq-g to break into
- the kernel debugger.
-
- kgdboc= [KGDB,HW] kgdb over consoles.
- Requires a tty driver that supports console polling,
- or a supported polling keyboard driver (non-usb).
- Serial only format: <serial_device>[,baud]
- keyboard only format: kbd
- keyboard and serial format: kbd,<serial_device>[,baud]
- Optional Kernel mode setting:
- kms, kbd format: kms,kbd
- kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
-
- kgdbwait [KGDB] Stop kernel execution and enter the
- kernel debugger at the earliest opportunity.
-
- kmac= [MIPS] korina ethernet MAC address.
- Configure the RouterBoard 532 series on-chip
- Ethernet adapter MAC address.
-
- kmemleak= [KNL] Boot-time kmemleak enable/disable
- Valid arguments: on, off
- Default: on
- Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
- the default is off.
-
- kmemcheck= [X86] Boot-time kmemcheck enable/disable/one-shot mode
- Valid arguments: 0, 1, 2
- kmemcheck=0 (disabled)
- kmemcheck=1 (enabled)
- kmemcheck=2 (one-shot mode)
- Default: 2 (one-shot mode)
-
- kstack=N [X86] Print N words from the kernel stack
- in oops dumps.
-
- kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
- Default is 0 (don't ignore, but inject #GP)
-
- kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
- KVM MMU at runtime.
- Default is 0 (off)
-
- kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
- Default is 1 (enabled)
-
- kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
- for all guests.
- Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
-
- kvm-intel.ept= [KVM,Intel] Disable extended page tables
- (virtualized MMU) support on capable Intel chips.
- Default is 1 (enabled)
-
- kvm-intel.emulate_invalid_guest_state=
- [KVM,Intel] Enable emulation of invalid guest states
- Default is 0 (disabled)
-
- kvm-intel.flexpriority=
- [KVM,Intel] Disable FlexPriority feature (TPR shadow).
- Default is 1 (enabled)
-
- kvm-intel.nested=
- [KVM,Intel] Enable VMX nesting (nVMX).
- Default is 0 (disabled)
-
- kvm-intel.unrestricted_guest=
- [KVM,Intel] Disable unrestricted guest feature
- (virtualized real and unpaged mode) on capable
- Intel chips. Default is 1 (enabled)
-
- kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
- feature (tagged TLBs) on capable Intel chips.
- Default is 1 (enabled)
-
- l2cr= [PPC]
-
- l3cr= [PPC]
-
- lapic [X86-32,APIC] Enable the local APIC even if BIOS
- disabled it.
-
- lapic= [x86,APIC] "notscdeadline" Do not use TSC deadline
- value for LAPIC timer one-shot implementation. Default
- back to the programmable timer unit in the LAPIC.
-
- lapic_timer_c2_ok [X86,APIC] trust the local apic timer
- in C2 power state.
-
- libata.dma= [LIBATA] DMA control
- libata.dma=0 Disable all PATA and SATA DMA
- libata.dma=1 PATA and SATA Disk DMA only
- libata.dma=2 ATAPI (CDROM) DMA only
- libata.dma=4 Compact Flash DMA only
- Combinations also work, so libata.dma=3 enables DMA
- for disks and CDROMs, but not CFs.
-
- libata.ignore_hpa= [LIBATA] Ignore HPA limit
- libata.ignore_hpa=0 keep BIOS limits (default)
- libata.ignore_hpa=1 ignore limits, using full disk
-
- libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
- when set.
- Format: <int>
-
- libata.force= [LIBATA] Force configurations. The format is comma
- separated list of "[ID:]VAL" where ID is
- PORT[.DEVICE]. PORT and DEVICE are decimal numbers
- matching port, link or device. Basically, it matches
- the ATA ID string printed on console by libata. If
- the whole ID part is omitted, the last PORT and DEVICE
- values are used. If ID hasn't been specified yet, the
- configuration applies to all ports, links and devices.
-
- If only DEVICE is omitted, the parameter applies to
- the port and all links and devices behind it. DEVICE
- number of 0 either selects the first device or the
- first fan-out link behind PMP device. It does not
- select the host link. DEVICE number of 15 selects the
- host link and device attached to it.
-
- The VAL specifies the configuration to force. As long
- as there's no ambiguity shortcut notation is allowed.
- For example, both 1.5 and 1.5G would work for 1.5Gbps.
- The following configurations can be forced.
-
- * Cable type: 40c, 80c, short40c, unk, ign or sata.
- Any ID with matching PORT is used.
-
- * SATA link speed limit: 1.5Gbps or 3.0Gbps.
-
- * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
- udma[/][16,25,33,44,66,100,133] notation is also
- allowed.
-
- * [no]ncq: Turn on or off NCQ.
-
- * [no]ncqtrim: Turn off queued DSM TRIM.
-
- * nohrst, nosrst, norst: suppress hard, soft
- and both resets.
-
- * rstonce: only attempt one reset during
- hot-unplug link recovery
-
- * dump_id: dump IDENTIFY data.
-
- * atapi_dmadir: Enable ATAPI DMADIR bridge support
-
- * disable: Disable this device.
-
- If there are multiple matching configurations changing
- the same attribute, the last one is used.
-
- memblock=debug [KNL] Enable memblock debug messages.
-
- load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/blockdev/ramdisk.txt.
-
- lockd.nlm_grace_period=P [NFS] Assign grace period.
- Format: <integer>
-
- lockd.nlm_tcpport=N [NFS] Assign TCP port.
- Format: <integer>
-
- lockd.nlm_timeout=T [NFS] Assign timeout value.
- Format: <integer>
-
- lockd.nlm_udpport=M [NFS] Assign UDP port.
- Format: <integer>
-
- locktorture.nreaders_stress= [KNL]
- Set the number of locking read-acquisition kthreads.
- Defaults to being automatically set based on the
- number of online CPUs.
-
- locktorture.nwriters_stress= [KNL]
- Set the number of locking write-acquisition kthreads.
-
- locktorture.onoff_holdoff= [KNL]
- Set time (s) after boot for CPU-hotplug testing.
-
- locktorture.onoff_interval= [KNL]
- Set time (s) between CPU-hotplug operations, or
- zero to disable CPU-hotplug testing.
-
- locktorture.shuffle_interval= [KNL]
- Set task-shuffle interval (jiffies). Shuffling
- tasks allows some CPUs to go into dyntick-idle
- mode during the locktorture test.
-
- locktorture.shutdown_secs= [KNL]
- Set time (s) after boot system shutdown. This
- is useful for hands-off automated testing.
-
- locktorture.stat_interval= [KNL]
- Time (s) between statistics printk()s.
-
- locktorture.stutter= [KNL]
- Time (s) to stutter testing, for example,
- specifying five seconds causes the test to run for
- five seconds, wait for five seconds, and so on.
- This tests the locking primitive's ability to
- transition abruptly to and from idle.
-
- locktorture.torture_runnable= [BOOT]
- Start locktorture running at boot time.
-
- locktorture.torture_type= [KNL]
- Specify the locking implementation to test.
-
- locktorture.verbose= [KNL]
- Enable additional printk() statements.
-
- logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
- Format: <irq>
-
- loglevel= All Kernel Messages with a loglevel smaller than the
- console loglevel will be printed to the console. It can
- also be changed with klogd or other programs. The
- loglevels are defined as follows:
-
- 0 (KERN_EMERG) system is unusable
- 1 (KERN_ALERT) action must be taken immediately
- 2 (KERN_CRIT) critical conditions
- 3 (KERN_ERR) error conditions
- 4 (KERN_WARNING) warning conditions
- 5 (KERN_NOTICE) normal but significant condition
- 6 (KERN_INFO) informational
- 7 (KERN_DEBUG) debug-level messages
-
- log_buf_len=n[KMG] Sets the size of the printk ring buffer,
- in bytes. n must be a power of two and greater
- than the minimal size. The minimal size is defined
- by LOG_BUF_SHIFT kernel config parameter. There is
- also CONFIG_LOG_CPU_MAX_BUF_SHIFT config parameter
- that allows to increase the default size depending on
- the number of CPUs. See init/Kconfig for more details.
-
- logo.nologo [FB] Disables display of the built-in Linux logo.
- This may be used to provide more screen space for
- kernel log messages and is useful when debugging
- kernel boot problems.
-
- lp=0 [LP] Specify parallel ports to use, e.g,
- lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
- lp=reset first parallel port). 'lp=0' disables the
- lp=auto printer driver. 'lp=reset' (which can be
- specified in addition to the ports) causes
- attached printers to be reset. Using
- lp=port1,port2,... specifies the parallel ports
- to associate lp devices with, starting with
- lp0. A port specification may be 'none' to skip
- that lp device, or a parport name such as
- 'parport0'. Specifying 'lp=auto' instead of a
- port specification list means that device IDs
- from each port should be examined, to see if
- an IEEE 1284-compliant printer is attached; if
- so, the driver will manage that printer.
- See also header of drivers/char/lp.c.
-
- lpj=n [KNL]
- Sets loops_per_jiffy to given constant, thus avoiding
- time-consuming boot-time autodetection (up to 250 ms per
- CPU). 0 enables autodetection (default). To determine
- the correct value for your kernel, boot with normal
- autodetection and see what value is printed. Note that
- on SMP systems the preset will be applied to all CPUs,
- which is likely to cause problems if your CPUs need
- significantly divergent settings. An incorrect value
- will cause delays in the kernel to be wrong, leading to
- unpredictable I/O errors and other breakage. Although
- unlikely, in the extreme case this might damage your
- hardware.
-
- ltpc= [NET]
- Format: <io>,<irq>,<dma>
-
- machvec= [IA-64] Force the use of a particular machine-vector
- (machvec) in a generic kernel.
- Example: machvec=hpzx1_swiotlb
-
- machtype= [Loongson] Share the same kernel image file between different
- yeeloong laptop.
- Example: machtype=lemote-yeeloong-2f-7inch
-
- max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
- than or equal to this physical address is ignored.
-
- maxcpus= [SMP] Maximum number of processors that an SMP kernel
- will bring up during bootup. maxcpus=n : n >= 0 limits
- the kernel to bring up 'n' processors. Surely after
- bootup you can bring up the other plugged cpu by executing
- "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
- only takes effect during system bootup.
- While n=0 is a special case, it is equivalent to "nosmp",
- which also disables the IO APIC.
-
- max_loop= [LOOP] The number of loop block devices that get
- (loop.max_loop) unconditionally pre-created at init time. The default
- number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
- of statically allocating a predefined number, loop
- devices can be requested on-demand with the
- /dev/loop-control interface.
-
- mce [X86-32] Machine Check Exception
-
- mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
-
- md= [HW] RAID subsystems devices and level
- See Documentation/md.txt.
-
- mdacon= [MDA]
- Format: <first>,<last>
- Specifies range of consoles to be captured by the MDA.
-
- mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
- Amount of memory to be used when the kernel is not able
- to see the whole system memory or for test.
- [X86] Work as limiting max address. Use together
- with memmap= to avoid physical address space collisions.
- Without memmap= PCI devices could be placed at addresses
- belonging to unused RAM.
-
- mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
- memory.
-
- memchunk=nn[KMG]
- [KNL,SH] Allow user to override the default size for
- per-device physically contiguous DMA buffers.
-
- memhp_default_state=online/offline
- [KNL] Set the initial state for the memory hotplug
- onlining policy. If not specified, the default value is
- set according to the
- CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config
- option.
- See Documentation/memory-hotplug.txt.
-
- memmap=exactmap [KNL,X86] Enable setting of an exact
- E820 memory map, as specified by the user.
- Such memmap=exactmap lines can be constructed based on
- BIOS output or other requirements. See the memmap=nn@ss
- option description.
-
- memmap=nn[KMG]@ss[KMG]
- [KNL] Force usage of a specific region of memory.
- Region of memory to be used is from ss to ss+nn.
-
- memmap=nn[KMG]#ss[KMG]
- [KNL,ACPI] Mark specific memory as ACPI data.
- Region of memory to be marked is from ss to ss+nn.
-
- memmap=nn[KMG]$ss[KMG]
- [KNL,ACPI] Mark specific memory as reserved.
- Region of memory to be reserved is from ss to ss+nn.
- Example: Exclude memory from 0x18690000-0x1869ffff
- memmap=64K$0x18690000
- or
- memmap=0x10000$0x18690000
-
- memmap=nn[KMG]!ss[KMG]
- [KNL,X86] Mark specific memory as protected.
- Region of memory to be used, from ss to ss+nn.
- The memory region may be marked as e820 type 12 (0xc)
- and is NVDIMM or ADR memory.
-
- memory_corruption_check=0/1 [X86]
- Some BIOSes seem to corrupt the first 64k of
- memory when doing things like suspend/resume.
- Setting this option will scan the memory
- looking for corruption. Enabling this will
- both detect corruption and prevent the kernel
- from using the memory being corrupted.
- However, its intended as a diagnostic tool; if
- repeatable BIOS-originated corruption always
- affects the same memory, you can use memmap=
- to prevent the kernel from using that memory.
-
- memory_corruption_check_size=size [X86]
- By default it checks for corruption in the low
- 64k, making this memory unavailable for normal
- use. Use this parameter to scan for
- corruption in more or less memory.
-
- memory_corruption_check_period=seconds [X86]
- By default it checks for corruption every 60
- seconds. Use this parameter to check at some
- other rate. 0 disables periodic checking.
-
- memtest= [KNL,X86,ARM] Enable memtest
- Format: <integer>
- default : 0 <disable>
- Specifies the number of memtest passes to be
- performed. Each pass selects another test
- pattern from a given set of patterns. Memtest
- fills the memory with this pattern, validates
- memory contents and reserves bad memory
- regions that are detected.
-
- meye.*= [HW] Set MotionEye Camera parameters
- See Documentation/video4linux/meye.txt.
-
- mfgpt_irq= [IA-32] Specify the IRQ to use for the
- Multi-Function General Purpose Timers on AMD Geode
- platforms.
-
- mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
- the BIOS has incorrectly applied a workaround. TinyBIOS
- version 0.98 is known to be affected, 0.99 fixes the
- problem by letting the user disable the workaround.
-
- mga= [HW,DRM]
-
- min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
- physical address is ignored.
-
- mini2440= [ARM,HW,KNL]
- Format:[0..2][b][c][t]
- Default: "0tb"
- MINI2440 configuration specification:
- 0 - The attached screen is the 3.5" TFT
- 1 - The attached screen is the 7" TFT
- 2 - The VGA Shield is attached (1024x768)
- Leaving out the screen size parameter will not load
- the TFT driver, and the framebuffer will be left
- unconfigured.
- b - Enable backlight. The TFT backlight pin will be
- linked to the kernel VESA blanking code and a GPIO
- LED. This parameter is not necessary when using the
- VGA shield.
- c - Enable the s3c camera interface.
- t - Reserved for enabling touchscreen support. The
- touchscreen support is not enabled in the mainstream
- kernel as of 2.6.30, a preliminary port can be found
- in the "bleeding edge" mini2440 support kernel at
- http://repo.or.cz/w/linux-2.6/mini2440.git
-
- mminit_loglevel=
- [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
- parameter allows control of the logging verbosity for
- the additional memory initialisation checks. A value
- of 0 disables mminit logging and a level of 4 will
- log everything. Information is printed at KERN_DEBUG
- so loglevel=8 may also need to be specified.
-
- module.sig_enforce
- [KNL] When CONFIG_MODULE_SIG is set, this means that
- modules without (valid) signatures will fail to load.
- Note that if CONFIG_MODULE_SIG_FORCE is set, that
- is always true, so this option does nothing.
-
- module_blacklist= [KNL] Do not load a comma-separated list of
- modules. Useful for debugging problem modules.
-
- mousedev.tap_time=
- [MOUSE] Maximum time between finger touching and
- leaving touchpad surface for touch to be considered
- a tap and be reported as a left button click (for
- touchpads working in absolute mode only).
- Format: <msecs>
- mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
- reporting absolute coordinates, such as tablets
- mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
- reporting absolute coordinates, such as tablets
-
- movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
- is similar to kernelcore except it specifies the
- amount of memory used for migratable allocations.
- If both kernelcore and movablecore is specified,
- then kernelcore will be at *least* the specified
- value but may be more. If movablecore on its own
- is specified, the administrator must be careful
- that the amount of memory usable for all allocations
- is not too small.
-
- movable_node [KNL,X86] Boot-time switch to enable the effects
- of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
-
- MTD_Partition= [MTD]
- Format: <name>,<region-number>,<size>,<offset>
-
- MTD_Region= [MTD] Format:
- <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
-
- mtdparts= [MTD]
- See drivers/mtd/cmdlinepart.c.
-
- multitce=off [PPC] This parameter disables the use of the pSeries
- firmware feature for updating multiple TCE entries
- at a time.
-
- onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
-
- Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
-
- boundary - index of last SLC block on Flex-OneNAND.
- The remaining blocks are configured as MLC blocks.
- lock - Configure if Flex-OneNAND boundary should be locked.
- Once locked, the boundary cannot be changed.
- 1 indicates lock status, 0 indicates unlock status.
-
- mtdset= [ARM]
- ARM/S3C2412 JIVE boot control
-
- See arch/arm/mach-s3c2412/mach-jive.c
-
- mtouchusb.raw_coordinates=
- [HW] Make the MicroTouch USB driver use raw coordinates
- ('y', default) or cooked coordinates ('n')
-
- mtrr_chunk_size=nn[KMG] [X86]
- used for mtrr cleanup. It is largest continuous chunk
- that could hold holes aka. UC entries.
-
- mtrr_gran_size=nn[KMG] [X86]
- Used for mtrr cleanup. It is granularity of mtrr block.
- Default is 1.
- Large value could prevent small alignment from
- using up MTRRs.
-
- mtrr_spare_reg_nr=n [X86]
- Format: <integer>
- Range: 0,7 : spare reg number
- Default : 1
- Used for mtrr cleanup. It is spare mtrr entries number.
- Set to 2 or more if your graphical card needs more.
-
- n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
-
- netdev= [NET] Network devices parameters
- Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
- Note that mem_start is often overloaded to mean
- something different and driver-specific.
- This usage is only documented in each driver source
- file if at all.
-
- nf_conntrack.acct=
- [NETFILTER] Enable connection tracking flow accounting
- 0 to disable accounting
- 1 to enable accounting
- Default value is 0.
-
- nfsaddrs= [NFS] Deprecated. Use ip= instead.
- See Documentation/filesystems/nfs/nfsroot.txt.
-
- nfsroot= [NFS] nfs root filesystem for disk-less boxes.
- See Documentation/filesystems/nfs/nfsroot.txt.
-
- nfsrootdebug [NFS] enable nfsroot debugging messages.
- See Documentation/filesystems/nfs/nfsroot.txt.
-
- nfs.callback_nr_threads=
- [NFSv4] set the total number of threads that the
- NFS client will assign to service NFSv4 callback
- requests.
-
- nfs.callback_tcpport=
- [NFS] set the TCP port on which the NFSv4 callback
- channel should listen.
-
- nfs.cache_getent=
- [NFS] sets the pathname to the program which is used
- to update the NFS client cache entries.
-
- nfs.cache_getent_timeout=
- [NFS] sets the timeout after which an attempt to
- update a cache entry is deemed to have failed.
-
- nfs.idmap_cache_timeout=
- [NFS] set the maximum lifetime for idmapper cache
- entries.
-
- nfs.enable_ino64=
- [NFS] enable 64-bit inode numbers.
- If zero, the NFS client will fake up a 32-bit inode
- number for the readdir() and stat() syscalls instead
- of returning the full 64-bit number.
- The default is to return 64-bit inode numbers.
-
- nfs.max_session_cb_slots=
- [NFSv4.1] Sets the maximum number of session
- slots the client will assign to the callback
- channel. This determines the maximum number of
- callbacks the client will process in parallel for
- a particular server.
-
- nfs.max_session_slots=
- [NFSv4.1] Sets the maximum number of session slots
- the client will attempt to negotiate with the server.
- This limits the number of simultaneous RPC requests
- that the client can send to the NFSv4.1 server.
- Note that there is little point in setting this
- value higher than the max_tcp_slot_table_limit.
-
- nfs.nfs4_disable_idmapping=
- [NFSv4] When set to the default of '1', this option
- ensures that both the RPC level authentication
- scheme and the NFS level operations agree to use
- numeric uids/gids if the mount is using the
- 'sec=sys' security flavour. In effect it is
- disabling idmapping, which can make migration from
- legacy NFSv2/v3 systems to NFSv4 easier.
- Servers that do not support this mode of operation
- will be autodetected by the client, and it will fall
- back to using the idmapper.
- To turn off this behaviour, set the value to '0'.
- nfs.nfs4_unique_id=
- [NFS4] Specify an additional fixed unique ident-
- ification string that NFSv4 clients can insert into
- their nfs_client_id4 string. This is typically a
- UUID that is generated at system install time.
-
- nfs.send_implementation_id =
- [NFSv4.1] Send client implementation identification
- information in exchange_id requests.
- If zero, no implementation identification information
- will be sent.
- The default is to send the implementation identification
- information.
-
- nfs.recover_lost_locks =
- [NFSv4] Attempt to recover locks that were lost due
- to a lease timeout on the server. Please note that
- doing this risks data corruption, since there are
- no guarantees that the file will remain unchanged
- after the locks are lost.
- If you want to enable the kernel legacy behaviour of
- attempting to recover these locks, then set this
- parameter to '1'.
- The default parameter value of '0' causes the kernel
- not to attempt recovery of lost locks.
-
- nfs4.layoutstats_timer =
- [NFSv4.2] Change the rate at which the kernel sends
- layoutstats to the pNFS metadata server.
-
- Setting this to value to 0 causes the kernel to use
- whatever value is the default set by the layout
- driver. A non-zero value sets the minimum interval
- in seconds between layoutstats transmissions.
-
- nfsd.nfs4_disable_idmapping=
- [NFSv4] When set to the default of '1', the NFSv4
- server will return only numeric uids and gids to
- clients using auth_sys, and will accept numeric uids
- and gids from such clients. This is intended to ease
- migration from NFSv2/v3.
-
- objlayoutdriver.osd_login_prog=
- [NFS] [OBJLAYOUT] sets the pathname to the program which
- is used to automatically discover and login into new
- osd-targets. Please see:
- Documentation/filesystems/pnfs.txt for more explanations
-
- nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
- when a NMI is triggered.
- Format: [state][,regs][,debounce][,die]
-
- nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
- Format: [panic,][nopanic,][num]
- Valid num: 0 or 1
- 0 - turn hardlockup detector in nmi_watchdog off
- 1 - turn hardlockup detector in nmi_watchdog on
- When panic is specified, panic when an NMI watchdog
- timeout occurs (or 'nopanic' to override the opposite
- default). To disable both hard and soft lockup detectors,
- please see 'nowatchdog'.
- This is useful when you use a panic=... timeout and
- need the box quickly up again.
-
- netpoll.carrier_timeout=
- [NET] Specifies amount of time (in seconds) that
- netpoll should wait for a carrier. By default netpoll
- waits 4 seconds.
-
- no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
- emulation library even if a 387 maths coprocessor
- is present.
-
- no_console_suspend
- [HW] Never suspend the console
- Disable suspending of consoles during suspend and
- hibernate operations. Once disabled, debugging
- messages can reach various consoles while the rest
- of the system is being put to sleep (ie, while
- debugging driver suspend/resume hooks). This may
- not work reliably with all consoles, but is known
- to work with serial and VGA consoles.
- To facilitate more flexible debugging, we also add
- console_suspend, a printk module parameter to control
- it. Users could use console_suspend (usually
- /sys/module/printk/parameters/console_suspend) to
- turn on/off it dynamically.
-
- noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
- caches in the slab allocator. Saves per-node memory,
- but will impact performance.
-
- noalign [KNL,ARM]
-
- noapic [SMP,APIC] Tells the kernel to not make use of any
- IOAPICs that may be present in the system.
-
- noautogroup Disable scheduler automatic task group creation.
-
- nobats [PPC] Do not use BATs for mapping kernel lowmem
- on "Classic" PPC cores.
-
- nocache [ARM]
-
- noclflush [BUGS=X86] Don't use the CLFLUSH instruction
-
- nodelayacct [KNL] Disable per-task delay accounting
-
- nodsp [SH] Disable hardware DSP at boot time.
-
- noefi Disable EFI runtime services support.
-
- noexec [IA-64]
-
- noexec [X86]
- On X86-32 available only on PAE configured kernels.
- noexec=on: enable non-executable mappings (default)
- noexec=off: disable non-executable mappings
-
- nosmap [X86]
- Disable SMAP (Supervisor Mode Access Prevention)
- even if it is supported by processor.
-
- nosmep [X86]
- Disable SMEP (Supervisor Mode Execution Prevention)
- even if it is supported by processor.
-
- noexec32 [X86-64]
- This affects only 32-bit executables.
- noexec32=on: enable non-executable mappings (default)
- read doesn't imply executable mappings
- noexec32=off: disable non-executable mappings
- read implies executable mappings
-
- nofpu [MIPS,SH] Disable hardware FPU at boot time.
-
- nofxsr [BUGS=X86-32] Disables x86 floating point extended
- register save and restore. The kernel will only save
- legacy floating-point registers on task switch.
-
- nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
-
- nosmt [KNL,S390] Disable symmetric multithreading (SMT).
- Equivalent to smt=1.
-
- noxsave [BUGS=X86] Disables x86 extended register state save
- and restore using xsave. The kernel will fallback to
- enabling legacy floating-point and sse state.
-
- noxsaveopt [X86] Disables xsaveopt used in saving x86 extended
- register states. The kernel will fall back to use
- xsave to save the states. By using this parameter,
- performance of saving the states is degraded because
- xsave doesn't support modified optimization while
- xsaveopt supports it on xsaveopt enabled systems.
-
- noxsaves [X86] Disables xsaves and xrstors used in saving and
- restoring x86 extended register state in compacted
- form of xsave area. The kernel will fall back to use
- xsaveopt and xrstor to save and restore the states
- in standard form of xsave area. By using this
- parameter, xsave area per process might occupy more
- memory on xsaves enabled systems.
-
- nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
- wfi(ARM) instruction doesn't work correctly and not to
- use it. This is also useful when using JTAG debugger.
-
- no_file_caps Tells the kernel not to honor file capabilities. The
- only way then for a file to be executed with privilege
- is to be setuid root or executed by root.
-
- nohalt [IA-64] Tells the kernel not to use the power saving
- function PAL_HALT_LIGHT when idle. This increases
- power-consumption. On the positive side, it reduces
- interrupt wake-up latency, which may improve performance
- in certain environments such as networked servers or
- real-time systems.
-
- nohibernate [HIBERNATION] Disable hibernation and resume.
-
- nohz= [KNL] Boottime enable/disable dynamic ticks
- Valid arguments: on, off
- Default: on
-
- nohz_full= [KNL,BOOT]
- The argument is a cpu list, as described above.
- In kernels built with CONFIG_NO_HZ_FULL=y, set
- the specified list of CPUs whose tick will be stopped
- whenever possible. The boot CPU will be forced outside
- the range to maintain the timekeeping.
- The CPUs in this range must also be included in the
- rcu_nocbs= set.
-
- noiotrap [SH] Disables trapped I/O port accesses.
-
- noirqdebug [X86-32] Disables the code which attempts to detect and
- disable unhandled interrupt sources.
-
- no_timer_check [X86,APIC] Disables the code which tests for
- broken timer IRQ sources.
-
- noisapnp [ISAPNP] Disables ISA PnP code.
-
- noinitrd [RAM] Tells the kernel not to load any configured
- initial RAM disk.
-
- nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
- remapping.
- [Deprecated - use intremap=off]
-
- nointroute [IA-64]
-
- noinvpcid [X86] Disable the INVPCID cpu feature.
-
- nojitter [IA-64] Disables jitter checking for ITC timers.
-
- no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
-
- no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
- fault handling.
-
- no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
- steal time is computed, but won't influence scheduler
- behaviour
-
- nolapic [X86-32,APIC] Do not enable or use the local APIC.
-
- nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
-
- noltlbs [PPC] Do not use large page/tlb entries for kernel
- lowmem mapping on PPC40x and PPC8xx
-
- nomca [IA-64] Disable machine check abort handling
-
- nomce [X86-32] Disable Machine Check Exception
-
- nomfgpt [X86-32] Disable Multi-Function General Purpose
- Timer usage (for AMD Geode machines).
-
- nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
- shutdown the other cpus. Instead use the REBOOT_VECTOR
- irq.
-
- nomodule Disable module load
-
- nopat [X86] Disable PAT (page attribute table extension of
- pagetables) support.
-
- norandmaps Don't use address space randomization. Equivalent to
- echo 0 > /proc/sys/kernel/randomize_va_space
-
- noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
-
- noreplace-smp [X86-32,SMP] Don't replace SMP instructions
- with UP alternatives
-
- nordrand [X86] Disable kernel use of the RDRAND and
- RDSEED instructions even if they are supported
- by the processor. RDRAND and RDSEED are still
- available to user space applications.
-
- noresume [SWSUSP] Disables resume and restores original swap
- space.
-
- no-scroll [VGA] Disables scrollback.
- This is required for the Braillex ib80-piezo Braille
- reader made by F.H. Papenmeier (Germany).
-
- nosbagart [IA-64]
-
- nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
-
- nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
- and disable the IO APIC. legacy for "maxcpus=0".
-
- nosoftlockup [KNL] Disable the soft-lockup detector.
-
- nosync [HW,M68K] Disables sync negotiation for all devices.
-
- notsc [BUGS=X86-32] Disable Time Stamp Counter
-
- nowatchdog [KNL] Disable both lockup detectors, i.e.
- soft-lockup and NMI watchdog (hard-lockup).
-
- nowb [ARM]
-
- nox2apic [X86-64,APIC] Do not enable x2APIC mode.
-
- cpu0_hotplug [X86] Turn on CPU0 hotplug feature when
- CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off.
- Some features depend on CPU0. Known dependencies are:
- 1. Resume from suspend/hibernate depends on CPU0.
- Suspend/hibernate will fail if CPU0 is offline and you
- need to online CPU0 before suspend/hibernate.
- 2. PIC interrupts also depend on CPU0. CPU0 can't be
- removed if a PIC interrupt is detected.
- It's said poweroff/reboot may depend on CPU0 on some
- machines although I haven't seen such issues so far
- after CPU0 is offline on a few tested machines.
- If the dependencies are under your control, you can
- turn on cpu0_hotplug.
-
- nptcg= [IA-64] Override max number of concurrent global TLB
- purges which is reported from either PAL_VM_SUMMARY or
- SAL PALO.
-
- nr_cpus= [SMP] Maximum number of processors that an SMP kernel
- could support. nr_cpus=n : n >= 1 limits the kernel to
- support 'n' processors. It could be larger than the
- number of already plugged CPU during bootup, later in
- runtime you can physically add extra cpu until it reaches
- n. So during boot up some boot time memory for per-cpu
- variables need be pre-allocated for later physical cpu
- hot plugging.
-
- nr_uarts= [SERIAL] maximum number of UARTs to be registered.
-
- numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing.
- Allowed values are enable and disable
-
- numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
- one of ['zone', 'node', 'default'] can be specified
- This can be set from sysctl after boot.
- See Documentation/sysctl/vm.txt for details.
-
- ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
- See Documentation/debugging-via-ohci1394.txt for more
- info.
-
- olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
- Rather than timing out after 20 ms if an EC
- command is not properly ACKed, override the length
- of the timeout. We have interrupts disabled while
- waiting for the ACK, so if this is set too high
- interrupts *may* be lost!
-
- omap_mux= [OMAP] Override bootloader pin multiplexing.
- Format: <mux_mode0.mode_name=value>...
- For example, to override I2C bus2:
- omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
-
- oprofile.timer= [HW]
- Use timer interrupt instead of performance counters
-
- oprofile.cpu_type= Force an oprofile cpu type
- This might be useful if you have an older oprofile
- userland or if you want common events.
- Format: { arch_perfmon }
- arch_perfmon: [X86] Force use of architectural
- perfmon on Intel CPUs instead of the
- CPU specific event set.
- timer: [X86] Force use of architectural NMI
- timer mode (see also oprofile.timer
- for generic hr timer mode)
-
- oops=panic Always panic on oopses. Default is to just kill the
- process, but there is a small probability of
- deadlocking the machine.
- This will also cause panics on machine check exceptions.
- Useful together with panic=30 to trigger a reboot.
-
- OSS [HW,OSS]
- See Documentation/sound/oss/oss-parameters.txt
-
- page_owner= [KNL] Boot-time page_owner enabling option.
- Storage of the information about who allocated
- each page is disabled in default. With this switch,
- we can turn it on.
- on: enable the feature
-
- page_poison= [KNL] Boot-time parameter changing the state of
- poisoning on the buddy allocator.
- off: turn off poisoning
- on: turn on poisoning
-
- panic= [KNL] Kernel behaviour on panic: delay <timeout>
- timeout > 0: seconds before rebooting
- timeout = 0: wait forever
- timeout < 0: reboot immediately
- Format: <timeout>
-
- panic_on_warn panic() instead of WARN(). Useful to cause kdump
- on a WARN().
-
- crash_kexec_post_notifiers
- Run kdump after running panic-notifiers and dumping
- kmsg. This only for the users who doubt kdump always
- succeeds in any situation.
- Note that this also increases risks of kdump failure,
- because some panic notifiers can make the crashed
- kernel more unstable.
-
- parkbd.port= [HW] Parallel port number the keyboard adapter is
- connected to, default is 0.
- Format: <parport#>
- parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
- 0 for XT, 1 for AT (default is AT).
- Format: <mode>
-
- parport= [HW,PPT] Specify parallel ports. 0 disables.
- Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
- Use 'auto' to force the driver to use any
- IRQ/DMA settings detected (the default is to
- ignore detected IRQ/DMA settings because of
- possible conflicts). You can specify the base
- address, IRQ, and DMA settings; IRQ and DMA
- should be numbers, or 'auto' (for using detected
- settings on that particular port), or 'nofifo'
- (to avoid using a FIFO even if it is detected).
- Parallel ports are assigned in the order they
- are specified on the command line, starting
- with parport0.
-
- parport_init_mode= [HW,PPT]
- Configure VIA parallel port to operate in
- a specific mode. This is necessary on Pegasos
- computer where firmware has no options for setting
- up parallel port mode and sets it to spp.
- Currently this function knows 686a and 8231 chips.
- Format: [spp|ps2|epp|ecp|ecpepp]
-
- pause_on_oops=
- Halt all CPUs after the first oops has been printed for
- the specified number of seconds. This is to be used if
- your oopses keep scrolling off the screen.
-
- pcbit= [HW,ISDN]
-
- pcd. [PARIDE]
- See header of drivers/block/paride/pcd.c.
- See also Documentation/blockdev/paride.txt.
-
- pci=option[,option...] [PCI] various PCI subsystem options:
- earlydump [X86] dump PCI config space before the kernel
- changes anything
- off [X86] don't probe for the PCI bus
- bios [X86-32] force use of PCI BIOS, don't access
- the hardware directly. Use this if your machine
- has a non-standard PCI host bridge.
- nobios [X86-32] disallow use of PCI BIOS, only direct
- hardware access methods are allowed. Use this
- if you experience crashes upon bootup and you
- suspect they are caused by the BIOS.
- conf1 [X86] Force use of PCI Configuration Access
- Mechanism 1 (config address in IO port 0xCF8,
- data in IO port 0xCFC, both 32-bit).
- conf2 [X86] Force use of PCI Configuration Access
- Mechanism 2 (IO port 0xCF8 is an 8-bit port for
- the function, IO port 0xCFA, also 8-bit, sets
- bus number. The config space is then accessed
- through ports 0xC000-0xCFFF).
- See http://wiki.osdev.org/PCI for more info
- on the configuration access mechanisms.
- noaer [PCIE] If the PCIEAER kernel config parameter is
- enabled, this kernel boot option can be used to
- disable the use of PCIE advanced error reporting.
- nodomains [PCI] Disable support for multiple PCI
- root domains (aka PCI segments, in ACPI-speak).
- nommconf [X86] Disable use of MMCONFIG for PCI
- Configuration
- check_enable_amd_mmconf [X86] check for and enable
- properly configured MMIO access to PCI
- config space on AMD family 10h CPU
- nomsi [MSI] If the PCI_MSI kernel config parameter is
- enabled, this kernel boot option can be used to
- disable the use of MSI interrupts system-wide.
- noioapicquirk [APIC] Disable all boot interrupt quirks.
- Safety option to keep boot IRQs enabled. This
- should never be necessary.
- ioapicreroute [APIC] Enable rerouting of boot IRQs to the
- primary IO-APIC for bridges that cannot disable
- boot IRQs. This fixes a source of spurious IRQs
- when the system masks IRQs.
- noioapicreroute [APIC] Disable workaround that uses the
- boot IRQ equivalent of an IRQ that connects to
- a chipset where boot IRQs cannot be disabled.
- The opposite of ioapicreroute.
- biosirq [X86-32] Use PCI BIOS calls to get the interrupt
- routing table. These calls are known to be buggy
- on several machines and they hang the machine
- when used, but on other computers it's the only
- way to get the interrupt routing table. Try
- this option if the kernel is unable to allocate
- IRQs or discover secondary PCI buses on your
- motherboard.
- rom [X86] Assign address space to expansion ROMs.
- Use with caution as certain devices share
- address decoders between ROMs and other
- resources.
- norom [X86] Do not assign address space to
- expansion ROMs that do not already have
- BIOS assigned address ranges.
- nobar [X86] Do not assign address space to the
- BARs that weren't assigned by the BIOS.
- irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
- assigned automatically to PCI devices. You can
- make the kernel exclude IRQs of your ISA cards
- this way.
- pirqaddr=0xAAAAA [X86] Specify the physical address
- of the PIRQ table (normally generated
- by the BIOS) if it is outside the
- F0000h-100000h range.
- lastbus=N [X86] Scan all buses thru bus #N. Can be
- useful if the kernel is unable to find your
- secondary buses and you want to tell it
- explicitly which ones they are.
- assign-busses [X86] Always assign all PCI bus
- numbers ourselves, overriding
- whatever the firmware may have done.
- usepirqmask [X86] Honor the possible IRQ mask stored
- in the BIOS $PIR table. This is needed on
- some systems with broken BIOSes, notably
- some HP Pavilion N5400 and Omnibook XE3
- notebooks. This will have no effect if ACPI
- IRQ routing is enabled.
- noacpi [X86] Do not use ACPI for IRQ routing
- or for PCI scanning.
- use_crs [X86] Use PCI host bridge window information
- from ACPI. On BIOSes from 2008 or later, this
- is enabled by default. If you need to use this,
- please report a bug.
- nocrs [X86] Ignore PCI host bridge windows from ACPI.
- If you need to use this, please report a bug.
- routeirq Do IRQ routing for all PCI devices.
- This is normally done in pci_enable_device(),
- so this option is a temporary workaround
- for broken drivers that don't call it.
- skip_isa_align [X86] do not align io start addr, so can
- handle more pci cards
- noearly [X86] Don't do any early type 1 scanning.
- This might help on some broken boards which
- machine check when some devices' config space
- is read. But various workarounds are disabled
- and some IOMMU drivers will not work.
- bfsort Sort PCI devices into breadth-first order.
- This sorting is done to get a device
- order compatible with older (<= 2.4) kernels.
- nobfsort Don't sort PCI devices into breadth-first order.
- pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
- tuning and use the BIOS-configured MPS defaults.
- pcie_bus_safe Set every device's MPS to the largest value
- supported by all devices below the root complex.
- pcie_bus_perf Set device MPS to the largest allowable MPS
- based on its parent bus. Also set MRRS (Max
- Read Request Size) to the largest supported
- value (no larger than the MPS that the device
- or bus can support) for best performance.
- pcie_bus_peer2peer Set every device's MPS to 128B, which
- every device is guaranteed to support. This
- configuration allows peer-to-peer DMA between
- any pair of devices, possibly at the cost of
- reduced performance. This also guarantees
- that hot-added devices will work.
- cbiosize=nn[KMG] The fixed amount of bus space which is
- reserved for the CardBus bridge's IO window.
- The default value is 256 bytes.
- cbmemsize=nn[KMG] The fixed amount of bus space which is
- reserved for the CardBus bridge's memory
- window. The default value is 64 megabytes.
- resource_alignment=
- Format:
- [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
- [<order of align>@]pci:<vendor>:<device>\
- [:<subvendor>:<subdevice>][; ...]
- Specifies alignment and device to reassign
- aligned memory resources.
- If <order of align> is not specified,
- PAGE_SIZE is used as alignment.
- PCI-PCI bridge can be specified, if resource
- windows need to be expanded.
- To specify the alignment for several
- instances of a device, the PCI vendor,
- device, subvendor, and subdevice may be
- specified, e.g., 4096@pci:8086:9c22:103c:198f
- ecrc= Enable/disable PCIe ECRC (transaction layer
- end-to-end CRC checking).
- bios: Use BIOS/firmware settings. This is the
- the default.
- off: Turn ECRC off
- on: Turn ECRC on.
- hpiosize=nn[KMG] The fixed amount of bus space which is
- reserved for hotplug bridge's IO window.
- Default size is 256 bytes.
- hpmemsize=nn[KMG] The fixed amount of bus space which is
- reserved for hotplug bridge's memory window.
- Default size is 2 megabytes.
- hpbussize=nn The minimum amount of additional bus numbers
- reserved for buses below a hotplug bridge.
- Default is 1.
- realloc= Enable/disable reallocating PCI bridge resources
- if allocations done by BIOS are too small to
- accommodate resources required by all child
- devices.
- off: Turn realloc off
- on: Turn realloc on
- realloc same as realloc=on
- noari do not use PCIe ARI.
- pcie_scan_all Scan all possible PCIe devices. Otherwise we
- only look for one device below a PCIe downstream
- port.
-
- pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
- Management.
- off Disable ASPM.
- force Enable ASPM even on devices that claim not to support it.
- WARNING: Forcing ASPM on may cause system lockups.
-
- pcie_hp= [PCIE] PCI Express Hotplug driver options:
- nomsi Do not use MSI for PCI Express Native Hotplug (this
- makes all PCIe ports use INTx for hotplug services).
-
- pcie_ports= [PCIE] PCIe ports handling:
- auto Ask the BIOS whether or not to use native PCIe services
- associated with PCIe ports (PME, hot-plug, AER). Use
- them only if that is allowed by the BIOS.
- native Use native PCIe services associated with PCIe ports
- unconditionally.
- compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
- ports driver.
-
- pcie_port_pm= [PCIE] PCIe port power management handling:
- off Disable power management of all PCIe ports
- force Forcibly enable power management of all PCIe ports
-
- pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
- nomsi Do not use MSI for native PCIe PME signaling (this makes
- all PCIe root ports use INTx for all services).
-
- pcmv= [HW,PCMCIA] BadgePAD 4
-
- pd_ignore_unused
- [PM]
- Keep all power-domains already enabled by bootloader on,
- even if no driver has claimed them. This is useful
- for debug and development, but should not be
- needed on a platform with proper driver support.
-
- pd. [PARIDE]
- See Documentation/blockdev/paride.txt.
-
- pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
- boot time.
- Format: { 0 | 1 }
- See arch/parisc/kernel/pdc_chassis.c
-
- percpu_alloc= Select which percpu first chunk allocator to use.
- Currently supported values are "embed" and "page".
- Archs may support subset or none of the selections.
- See comments in mm/percpu.c for details on each
- allocator. This parameter is primarily for debugging
- and performance comparison.
-
- pf. [PARIDE]
- See Documentation/blockdev/paride.txt.
-
- pg. [PARIDE]
- See Documentation/blockdev/paride.txt.
-
- pirq= [SMP,APIC] Manual mp-table setup
- See Documentation/x86/i386/IO-APIC.txt.
-
- plip= [PPT,NET] Parallel port network link
- Format: { parport<nr> | timid | 0 }
- See also Documentation/parport.txt.
-
- pmtmr= [X86] Manual setup of pmtmr I/O Port.
- Override pmtimer IOPort with a hex value.
- e.g. pmtmr=0x508
-
- pnp.debug=1 [PNP]
- Enable PNP debug messages (depends on the
- CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
- via /sys/module/pnp/parameters/debug. We always show
- current resource usage; turning this on also shows
- possible settings and some assignment information.
-
- pnpacpi= [ACPI]
- { off }
-
- pnpbios= [ISAPNP]
- { on | off | curr | res | no-curr | no-res }
-
- pnp_reserve_irq=
- [ISAPNP] Exclude IRQs for the autoconfiguration
-
- pnp_reserve_dma=
- [ISAPNP] Exclude DMAs for the autoconfiguration
-
- pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
- Ranges are in pairs (I/O port base and size).
-
- pnp_reserve_mem=
- [ISAPNP] Exclude memory regions for the
- autoconfiguration.
- Ranges are in pairs (memory base and size).
-
- ports= [IP_VS_FTP] IPVS ftp helper module
- Default is 21.
- Up to 8 (IP_VS_APP_MAX_PORTS) ports
- may be specified.
- Format: <port>,<port>....
-
- ppc_strict_facility_enable
- [PPC] This option catches any kernel floating point,
- Altivec, VSX and SPE outside of regions specifically
- allowed (eg kernel_enable_fpu()/kernel_disable_fpu()).
- There is some performance impact when enabling this.
-
- print-fatal-signals=
- [KNL] debug: print fatal signals
-
- If enabled, warn about various signal handling
- related application anomalies: too many signals,
- too many POSIX.1 timers, fatal signals causing a
- coredump - etc.
-
- If you hit the warning due to signal overflow,
- you might want to try "ulimit -i unlimited".
-
- default: off.
-
- printk.always_kmsg_dump=
- Trigger kmsg_dump for cases other than kernel oops or
- panics
- Format: <bool> (1/Y/y=enable, 0/N/n=disable)
- default: disabled
-
- printk.devkmsg={on,off,ratelimit}
- Control writing to /dev/kmsg.
- on - unlimited logging to /dev/kmsg from userspace
- off - logging to /dev/kmsg disabled
- ratelimit - ratelimit the logging
- Default: ratelimit
-
- printk.time= Show timing data prefixed to each printk message line
- Format: <bool> (1/Y/y=enable, 0/N/n=disable)
-
- processor.max_cstate= [HW,ACPI]
- Limit processor to maximum C-state
- max_cstate=9 overrides any DMI blacklist limit.
-
- processor.nocst [HW,ACPI]
- Ignore the _CST method to determine C-states,
- instead using the legacy FADT method
-
- profile= [KNL] Enable kernel profiling via /proc/profile
- Format: [schedule,]<number>
- Param: "schedule" - profile schedule points.
- Param: <number> - step/bucket size as a power of 2 for
- statistical time based profiling.
- Param: "sleep" - profile D-state sleeping (millisecs).
- Requires CONFIG_SCHEDSTATS
- Param: "kvm" - profile VM exits.
-
- prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
- before loading.
- See Documentation/blockdev/ramdisk.txt.
-
- psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
- probe for; one of (bare|imps|exps|lifebook|any).
- psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
- per second.
- psmouse.resetafter= [HW,MOUSE]
- Try to reset the device after so many bad packets
- (0 = never).
- psmouse.resolution=
- [HW,MOUSE] Set desired mouse resolution, in dpi.
- psmouse.smartscroll=
- [HW,MOUSE] Controls Logitech smartscroll autorepeat.
- 0 = disabled, 1 = enabled (default).
-
- pstore.backend= Specify the name of the pstore backend to use
-
- pt. [PARIDE]
- See Documentation/blockdev/paride.txt.
-
- pty.legacy_count=
- [KNL] Number of legacy pty's. Overwrites compiled-in
- default number.
-
- quiet [KNL] Disable most log messages
-
- r128= [HW,DRM]
-
- raid= [HW,RAID]
- See Documentation/md.txt.
-
- ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
- See Documentation/blockdev/ramdisk.txt.
-
- rcu_nocbs= [KNL]
- The argument is a cpu list, as described above.
-
- In kernels built with CONFIG_RCU_NOCB_CPU=y, set
- the specified list of CPUs to be no-callback CPUs.
- Invocation of these CPUs' RCU callbacks will
- be offloaded to "rcuox/N" kthreads created for
- that purpose, where "x" is "b" for RCU-bh, "p"
- for RCU-preempt, and "s" for RCU-sched, and "N"
- is the CPU number. This reduces OS jitter on the
- offloaded CPUs, which can be useful for HPC and
- real-time workloads. It can also improve energy
- efficiency for asymmetric multiprocessors.
-
- rcu_nocb_poll [KNL]
- Rather than requiring that offloaded CPUs
- (specified by rcu_nocbs= above) explicitly
- awaken the corresponding "rcuoN" kthreads,
- make these kthreads poll for callbacks.
- This improves the real-time response for the
- offloaded CPUs by relieving them of the need to
- wake up the corresponding kthread, but degrades
- energy efficiency by requiring that the kthreads
- periodically wake up to do the polling.
-
- rcutree.blimit= [KNL]
- Set maximum number of finished RCU callbacks to
- process in one batch.
-
- rcutree.dump_tree= [KNL]
- Dump the structure of the rcu_node combining tree
- out at early boot. This is used for diagnostic
- purposes, to verify correct tree setup.
-
- rcutree.gp_cleanup_delay= [KNL]
- Set the number of jiffies to delay each step of
- RCU grace-period cleanup. This only has effect
- when CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP is set.
-
- rcutree.gp_init_delay= [KNL]
- Set the number of jiffies to delay each step of
- RCU grace-period initialization. This only has
- effect when CONFIG_RCU_TORTURE_TEST_SLOW_INIT
- is set.
-
- rcutree.gp_preinit_delay= [KNL]
- Set the number of jiffies to delay each step of
- RCU grace-period pre-initialization, that is,
- the propagation of recent CPU-hotplug changes up
- the rcu_node combining tree. This only has effect
- when CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT is set.
-
- rcutree.rcu_fanout_exact= [KNL]
- Disable autobalancing of the rcu_node combining
- tree. This is used by rcutorture, and might
- possibly be useful for architectures having high
- cache-to-cache transfer latencies.
-
- rcutree.rcu_fanout_leaf= [KNL]
- Change the number of CPUs assigned to each
- leaf rcu_node structure. Useful for very
- large systems, which will choose the value 64,
- and for NUMA systems with large remote-access
- latencies, which will choose a value aligned
- with the appropriate hardware boundaries.
-
- rcutree.jiffies_till_sched_qs= [KNL]
- Set required age in jiffies for a
- given grace period before RCU starts
- soliciting quiescent-state help from
- rcu_note_context_switch().
-
- rcutree.jiffies_till_first_fqs= [KNL]
- Set delay from grace-period initialization to
- first attempt to force quiescent states.
- Units are jiffies, minimum value is zero,
- and maximum value is HZ.
-
- rcutree.jiffies_till_next_fqs= [KNL]
- Set delay between subsequent attempts to force
- quiescent states. Units are jiffies, minimum
- value is one, and maximum value is HZ.
-
- rcutree.kthread_prio= [KNL,BOOT]
- Set the SCHED_FIFO priority of the RCU per-CPU
- kthreads (rcuc/N). This value is also used for
- the priority of the RCU boost threads (rcub/N)
- and for the RCU grace-period kthreads (rcu_bh,
- rcu_preempt, and rcu_sched). If RCU_BOOST is
- set, valid values are 1-99 and the default is 1
- (the least-favored priority). Otherwise, when
- RCU_BOOST is not set, valid values are 0-99 and
- the default is zero (non-realtime operation).
-
- rcutree.rcu_nocb_leader_stride= [KNL]
- Set the number of NOCB kthread groups, which
- defaults to the square root of the number of
- CPUs. Larger numbers reduces the wakeup overhead
- on the per-CPU grace-period kthreads, but increases
- that same overhead on each group's leader.
-
- rcutree.qhimark= [KNL]
- Set threshold of queued RCU callbacks beyond which
- batch limiting is disabled.
-
- rcutree.qlowmark= [KNL]
- Set threshold of queued RCU callbacks below which
- batch limiting is re-enabled.
-
- rcutree.rcu_idle_gp_delay= [KNL]
- Set wakeup interval for idle CPUs that have
- RCU callbacks (RCU_FAST_NO_HZ=y).
-
- rcutree.rcu_idle_lazy_gp_delay= [KNL]
- Set wakeup interval for idle CPUs that have
- only "lazy" RCU callbacks (RCU_FAST_NO_HZ=y).
- Lazy RCU callbacks are those which RCU can
- prove do nothing more than free memory.
-
- rcuperf.gp_exp= [KNL]
- Measure performance of expedited synchronous
- grace-period primitives.
-
- rcuperf.holdoff= [KNL]
- Set test-start holdoff period. The purpose of
- this parameter is to delay the start of the
- test until boot completes in order to avoid
- interference.
-
- rcuperf.nreaders= [KNL]
- Set number of RCU readers. The value -1 selects
- N, where N is the number of CPUs. A value
- "n" less than -1 selects N-n+1, where N is again
- the number of CPUs. For example, -2 selects N
- (the number of CPUs), -3 selects N+1, and so on.
- A value of "n" less than or equal to -N selects
- a single reader.
-
- rcuperf.nwriters= [KNL]
- Set number of RCU writers. The values operate
- the same as for rcuperf.nreaders.
- N, where N is the number of CPUs
-
- rcuperf.perf_runnable= [BOOT]
- Start rcuperf running at boot time.
-
- rcuperf.shutdown= [KNL]
- Shut the system down after performance tests
- complete. This is useful for hands-off automated
- testing.
-
- rcuperf.perf_type= [KNL]
- Specify the RCU implementation to test.
-
- rcuperf.verbose= [KNL]
- Enable additional printk() statements.
-
- rcutorture.cbflood_inter_holdoff= [KNL]
- Set holdoff time (jiffies) between successive
- callback-flood tests.
-
- rcutorture.cbflood_intra_holdoff= [KNL]
- Set holdoff time (jiffies) between successive
- bursts of callbacks within a given callback-flood
- test.
-
- rcutorture.cbflood_n_burst= [KNL]
- Set the number of bursts making up a given
- callback-flood test. Set this to zero to
- disable callback-flood testing.
-
- rcutorture.cbflood_n_per_burst= [KNL]
- Set the number of callbacks to be registered
- in a given burst of a callback-flood test.
-
- rcutorture.fqs_duration= [KNL]
- Set duration of force_quiescent_state bursts
- in microseconds.
-
- rcutorture.fqs_holdoff= [KNL]
- Set holdoff time within force_quiescent_state bursts
- in microseconds.
-
- rcutorture.fqs_stutter= [KNL]
- Set wait time between force_quiescent_state bursts
- in seconds.
-
- rcutorture.gp_cond= [KNL]
- Use conditional/asynchronous update-side
- primitives, if available.
-
- rcutorture.gp_exp= [KNL]
- Use expedited update-side primitives, if available.
-
- rcutorture.gp_normal= [KNL]
- Use normal (non-expedited) asynchronous
- update-side primitives, if available.
-
- rcutorture.gp_sync= [KNL]
- Use normal (non-expedited) synchronous
- update-side primitives, if available. If all
- of rcutorture.gp_cond=, rcutorture.gp_exp=,
- rcutorture.gp_normal=, and rcutorture.gp_sync=
- are zero, rcutorture acts as if is interpreted
- they are all non-zero.
-
- rcutorture.n_barrier_cbs= [KNL]
- Set callbacks/threads for rcu_barrier() testing.
-
- rcutorture.nfakewriters= [KNL]
- Set number of concurrent RCU writers. These just
- stress RCU, they don't participate in the actual
- test, hence the "fake".
-
- rcutorture.nreaders= [KNL]
- Set number of RCU readers. The value -1 selects
- N-1, where N is the number of CPUs. A value
- "n" less than -1 selects N-n-2, where N is again
- the number of CPUs. For example, -2 selects N
- (the number of CPUs), -3 selects N+1, and so on.
-
- rcutorture.object_debug= [KNL]
- Enable debug-object double-call_rcu() testing.
-
- rcutorture.onoff_holdoff= [KNL]
- Set time (s) after boot for CPU-hotplug testing.
-
- rcutorture.onoff_interval= [KNL]
- Set time (s) between CPU-hotplug operations, or
- zero to disable CPU-hotplug testing.
-
- rcutorture.shuffle_interval= [KNL]
- Set task-shuffle interval (s). Shuffling tasks
- allows some CPUs to go into dyntick-idle mode
- during the rcutorture test.
-
- rcutorture.shutdown_secs= [KNL]
- Set time (s) after boot system shutdown. This
- is useful for hands-off automated testing.
-
- rcutorture.stall_cpu= [KNL]
- Duration of CPU stall (s) to test RCU CPU stall
- warnings, zero to disable.
-
- rcutorture.stall_cpu_holdoff= [KNL]
- Time to wait (s) after boot before inducing stall.
-
- rcutorture.stat_interval= [KNL]
- Time (s) between statistics printk()s.
-
- rcutorture.stutter= [KNL]
- Time (s) to stutter testing, for example, specifying
- five seconds causes the test to run for five seconds,
- wait for five seconds, and so on. This tests RCU's
- ability to transition abruptly to and from idle.
-
- rcutorture.test_boost= [KNL]
- Test RCU priority boosting? 0=no, 1=maybe, 2=yes.
- "Maybe" means test if the RCU implementation
- under test support RCU priority boosting.
-
- rcutorture.test_boost_duration= [KNL]
- Duration (s) of each individual boost test.
-
- rcutorture.test_boost_interval= [KNL]
- Interval (s) between each boost test.
-
- rcutorture.test_no_idle_hz= [KNL]
- Test RCU's dyntick-idle handling. See also the
- rcutorture.shuffle_interval parameter.
-
- rcutorture.torture_runnable= [BOOT]
- Start rcutorture running at boot time.
-
- rcutorture.torture_type= [KNL]
- Specify the RCU implementation to test.
-
- rcutorture.verbose= [KNL]
- Enable additional printk() statements.
-
- rcupdate.rcu_cpu_stall_suppress= [KNL]
- Suppress RCU CPU stall warning messages.
-
- rcupdate.rcu_cpu_stall_timeout= [KNL]
- Set timeout for RCU CPU stall warning messages.
-
- rcupdate.rcu_expedited= [KNL]
- Use expedited grace-period primitives, for
- example, synchronize_rcu_expedited() instead
- of synchronize_rcu(). This reduces latency,
- but can increase CPU utilization, degrade
- real-time latency, and degrade energy efficiency.
- No effect on CONFIG_TINY_RCU kernels.
-
- rcupdate.rcu_normal= [KNL]
- Use only normal grace-period primitives,
- for example, synchronize_rcu() instead of
- synchronize_rcu_expedited(). This improves
- real-time latency, CPU utilization, and
- energy efficiency, but can expose users to
- increased grace-period latency. This parameter
- overrides rcupdate.rcu_expedited. No effect on
- CONFIG_TINY_RCU kernels.
-
- rcupdate.rcu_normal_after_boot= [KNL]
- Once boot has completed (that is, after
- rcu_end_inkernel_boot() has been invoked), use
- only normal grace-period primitives. No effect
- on CONFIG_TINY_RCU kernels.
-
- rcupdate.rcu_task_stall_timeout= [KNL]
- Set timeout in jiffies for RCU task stall warning
- messages. Disable with a value less than or equal
- to zero.
-
- rcupdate.rcu_self_test= [KNL]
- Run the RCU early boot self tests
-
- rcupdate.rcu_self_test_bh= [KNL]
- Run the RCU bh early boot self tests
-
- rcupdate.rcu_self_test_sched= [KNL]
- Run the RCU sched early boot self tests
-
- rdinit= [KNL]
- Format: <full_path>
- Run specified binary instead of /init from the ramdisk,
- used for early userspace startup. See initrd.
-
- reboot= [KNL]
- Format (x86 or x86_64):
- [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
- [[,]s[mp]#### \
- [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \
- [[,]f[orce]
- Where reboot_mode is one of warm (soft) or cold (hard) or gpio,
- reboot_type is one of bios, acpi, kbd, triple, efi, or pci,
- reboot_force is either force or not specified,
- reboot_cpu is s[mp]#### with #### being the processor
- to be used for rebooting.
-
- relax_domain_level=
- [KNL, SMP] Set scheduler's default relax_domain_level.
- See Documentation/cgroup-v1/cpusets.txt.
-
- relative_sleep_states=
- [SUSPEND] Use sleep state labeling where the deepest
- state available other than hibernation is always "mem".
- Format: { "0" | "1" }
- 0 -- Traditional sleep state labels.
- 1 -- Relative sleep state labels.
-
- reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
-
- reservetop= [X86-32]
- Format: nn[KMG]
- Reserves a hole at the top of the kernel virtual
- address space.
-
- reservelow= [X86]
- Format: nn[K]
- Set the amount of memory to reserve for BIOS at
- the bottom of the address space.
-
- reset_devices [KNL] Force drivers to reset the underlying device
- during initialization.
-
- resume= [SWSUSP]
- Specify the partition device for software suspend
- Format:
- {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
-
- resume_offset= [SWSUSP]
- Specify the offset from the beginning of the partition
- given by "resume=" at which the swap header is located,
- in <PAGE_SIZE> units (needed only for swap files).
- See Documentation/power/swsusp-and-swap-files.txt
-
- resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
- read the resume files
-
- resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
- Useful for devices that are detected asynchronously
- (e.g. USB and MMC devices).
-
- hibernate= [HIBERNATION]
- noresume Don't check if there's a hibernation image
- present during boot.
- nocompress Don't compress/decompress hibernation images.
- no Disable hibernation and resume.
- protect_image Turn on image protection during restoration
- (that will set all pages holding image data
- during restoration read-only).
-
- retain_initrd [RAM] Keep initrd memory after extraction
-
- rfkill.default_state=
- 0 "airplane mode". All wifi, bluetooth, wimax, gps, fm,
- etc. communication is blocked by default.
- 1 Unblocked.
-
- rfkill.master_switch_mode=
- 0 The "airplane mode" button does nothing.
- 1 The "airplane mode" button toggles between everything
- blocked and the previous configuration.
- 2 The "airplane mode" button toggles between everything
- blocked and everything unblocked.
-
- rhash_entries= [KNL,NET]
- Set number of hash buckets for route cache
-
- ro [KNL] Mount root device read-only on boot
-
- rodata= [KNL]
- on Mark read-only kernel memory as read-only (default).
- off Leave read-only kernel memory writable for debugging.
-
- rockchip.usb_uart
- Enable the uart passthrough on the designated usb port
- on Rockchip SoCs. When active, the signals of the
- debug-uart get routed to the D+ and D- pins of the usb
- port and the regular usb controller gets disabled.
-
- root= [KNL] Root filesystem
- See name_to_dev_t comment in init/do_mounts.c.
-
- rootdelay= [KNL] Delay (in seconds) to pause before attempting to
- mount the root filesystem
-
- rootflags= [KNL] Set root filesystem mount option string
-
- rootfstype= [KNL] Set root filesystem type
-
- rootwait [KNL] Wait (indefinitely) for root device to show up.
- Useful for devices that are detected asynchronously
- (e.g. USB and MMC devices).
-
- rproc_mem=nn[KMG][@address]
- [KNL,ARM,CMA] Remoteproc physical memory block.
- Memory area to be used by remote processor image,
- managed by CMA.
-
- rw [KNL] Mount root device read-write on boot
-
- S [KNL] Run init in single mode
-
- s390_iommu= [HW,S390]
- Set s390 IOTLB flushing mode
- strict
- With strict flushing every unmap operation will result in
- an IOTLB flush. Default is lazy flushing before reuse,
- which is faster.
-
- sa1100ir [NET]
- See drivers/net/irda/sa1100_ir.c.
-
- sbni= [NET] Granch SBNI12 leased line adapter
-
- sched_debug [KNL] Enables verbose scheduler debug messages.
-
- schedstats= [KNL,X86] Enable or disable scheduled statistics.
- Allowed values are enable and disable. This feature
- incurs a small amount of overhead in the scheduler
- but is useful for debugging and performance tuning.
-
- skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
- xtime_lock contention on larger systems, and/or RCU lock
- contention on all systems with CONFIG_MAXSMP set.
- Format: { "0" | "1" }
- 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
- 1 -- enable.
- Note: increases power consumption, thus should only be
- enabled if running jitter sensitive (HPC/RT) workloads.
-
- security= [SECURITY] Choose a security module to enable at boot.
- If this boot parameter is not specified, only the first
- security module asking for security registration will be
- loaded. An invalid security module name will be treated
- as if no module has been chosen.
-
- selinux= [SELINUX] Disable or enable SELinux at boot time.
- Format: { "0" | "1" }
- See security/selinux/Kconfig help text.
- 0 -- disable.
- 1 -- enable.
- Default value is set via kernel config option.
- If enabled at boot time, /selinux/disable can be used
- later to disable prior to initial policy load.
-
- apparmor= [APPARMOR] Disable or enable AppArmor at boot time
- Format: { "0" | "1" }
- See security/apparmor/Kconfig help text
- 0 -- disable.
- 1 -- enable.
- Default value is set via kernel config option.
-
- serialnumber [BUGS=X86-32]
-
- shapers= [NET]
- Maximal number of shapers.
-
- show_msr= [x86] show boot-time MSR settings
- Format: { <integer> }
- Show boot-time (BIOS-initialized) MSR settings.
- The parameter means the number of CPUs to show,
- for example 1 means boot CPU only.
-
- simeth= [IA-64]
- simscsi=
-
- slram= [HW,MTD]
-
- slab_nomerge [MM]
- Disable merging of slabs with similar size. May be
- necessary if there is some reason to distinguish
- allocs to different slabs. Debug options disable
- merging on their own.
- For more information see Documentation/vm/slub.txt.
-
- slab_max_order= [MM, SLAB]
- Determines the maximum allowed order for slabs.
- A high setting may cause OOMs due to memory
- fragmentation. Defaults to 1 for systems with
- more than 32MB of RAM, 0 otherwise.
-
- slub_debug[=options[,slabs]] [MM, SLUB]
- Enabling slub_debug allows one to determine the
- culprit if slab objects become corrupted. Enabling
- slub_debug can create guard zones around objects and
- may poison objects when not in use. Also tracks the
- last alloc / free. For more information see
- Documentation/vm/slub.txt.
-
- slub_max_order= [MM, SLUB]
- Determines the maximum allowed order for slabs.
- A high setting may cause OOMs due to memory
- fragmentation. For more information see
- Documentation/vm/slub.txt.
-
- slub_min_objects= [MM, SLUB]
- The minimum number of objects per slab. SLUB will
- increase the slab order up to slub_max_order to
- generate a sufficiently large slab able to contain
- the number of objects indicated. The higher the number
- of objects the smaller the overhead of tracking slabs
- and the less frequently locks need to be acquired.
- For more information see Documentation/vm/slub.txt.
-
- slub_min_order= [MM, SLUB]
- Determines the minimum page order for slabs. Must be
- lower than slub_max_order.
- For more information see Documentation/vm/slub.txt.
-
- slub_nomerge [MM, SLUB]
- Same with slab_nomerge. This is supported for legacy.
- See slab_nomerge for more information.
-
- smart2= [HW]
- Format: <io1>[,<io2>[,...,<io8>]]
-
- smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
- smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
- smsc-ircc2.ircc_sir= [HW] SIR base I/O port
- smsc-ircc2.ircc_fir= [HW] FIR base I/O port
- smsc-ircc2.ircc_irq= [HW] IRQ line
- smsc-ircc2.ircc_dma= [HW] DMA channel
- smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
- 0: Toshiba Satellite 1800 (GP data pin select)
- 1: Fast pin select (default)
- 2: ATC IRMode
-
- smt [KNL,S390] Set the maximum number of threads (logical
- CPUs) to use per physical CPU on systems capable of
- symmetric multithreading (SMT). Will be capped to the
- actual hardware limit.
- Format: <integer>
- Default: -1 (no limit)
-
- softlockup_panic=
- [KNL] Should the soft-lockup detector generate panics.
- Format: <integer>
-
- softlockup_all_cpu_backtrace=
- [KNL] Should the soft-lockup detector generate
- backtraces on all cpus.
- Format: <integer>
-
- sonypi.*= [HW] Sony Programmable I/O Control Device driver
- See Documentation/laptops/sonypi.txt
-
- spia_io_base= [HW,MTD]
- spia_fio_base=
- spia_pedr=
- spia_peddr=
-
- stacktrace [FTRACE]
- Enabled the stack tracer on boot up.
-
- stacktrace_filter=[function-list]
- [FTRACE] Limit the functions that the stack tracer
- will trace at boot up. function-list is a comma separated
- list of functions. This list can be changed at run
- time by the stack_trace_filter file in the debugfs
- tracing directory. Note, this enables stack tracing
- and the stacktrace above is not needed.
-
- sti= [PARISC,HW]
- Format: <num>
- Set the STI (builtin display/keyboard on the HP-PARISC
- machines) console (graphic card) which should be used
- as the initial boot-console.
- See also comment in drivers/video/console/sticore.c.
-
- sti_font= [HW]
- See comment in drivers/video/console/sticore.c.
-
- stifb= [HW]
- Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
-
- sunrpc.min_resvport=
- sunrpc.max_resvport=
- [NFS,SUNRPC]
- SunRPC servers often require that client requests
- originate from a privileged port (i.e. a port in the
- range 0 < portnr < 1024).
- An administrator who wishes to reserve some of these
- ports for other uses may adjust the range that the
- kernel's sunrpc client considers to be privileged
- using these two parameters to set the minimum and
- maximum port values.
-
- sunrpc.svc_rpc_per_connection_limit=
- [NFS,SUNRPC]
- Limit the number of requests that the server will
- process in parallel from a single connection.
- The default value is 0 (no limit).
-
- sunrpc.pool_mode=
- [NFS]
- Control how the NFS server code allocates CPUs to
- service thread pools. Depending on how many NICs
- you have and where their interrupts are bound, this
- option will affect which CPUs will do NFS serving.
- Note: this parameter cannot be changed while the
- NFS server is running.
-
- auto the server chooses an appropriate mode
- automatically using heuristics
- global a single global pool contains all CPUs
- percpu one pool for each CPU
- pernode one pool for each NUMA node (equivalent
- to global on non-NUMA machines)
-
- sunrpc.tcp_slot_table_entries=
- sunrpc.udp_slot_table_entries=
- [NFS,SUNRPC]
- Sets the upper limit on the number of simultaneous
- RPC calls that can be sent from the client to a
- server. Increasing these values may allow you to
- improve throughput, but will also increase the
- amount of memory reserved for use by the client.
-
- suspend.pm_test_delay=
- [SUSPEND]
- Sets the number of seconds to remain in a suspend test
- mode before resuming the system (see
- /sys/power/pm_test). Only available when CONFIG_PM_DEBUG
- is set. Default value is 5.
-
- swapaccount=[0|1]
- [KNL] Enable accounting of swap in memory resource
- controller if no parameter or 1 is given or disable
- it if 0 is given (See Documentation/cgroup-v1/memory.txt)
-
- swiotlb= [ARM,IA-64,PPC,MIPS,X86]
- Format: { <int> | force }
- <int> -- Number of I/O TLB slabs
- force -- force using of bounce buffers even if they
- wouldn't be automatically used by the kernel
-
- switches= [HW,M68k]
-
- sysfs.deprecated=0|1 [KNL]
- Enable/disable old style sysfs layout for old udev
- on older distributions. When this option is enabled
- very new udev will not work anymore. When this option
- is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
- in older udev will not work anymore.
- Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
- the kernel configuration.
-
- sysrq_always_enabled
- [KNL]
- Ignore sysrq setting - this boot parameter will
- neutralize any effect of /proc/sys/kernel/sysrq.
- Useful for debugging.
-
- tcpmhash_entries= [KNL,NET]
- Set the number of tcp_metrics_hash slots.
- Default value is 8192 or 16384 depending on total
- ram pages. This is used to specify the TCP metrics
- cache size. See Documentation/networking/ip-sysctl.txt
- "tcp_no_metrics_save" section for more details.
-
- tdfx= [HW,DRM]
-
- test_suspend= [SUSPEND][,N]
- Specify "mem" (for Suspend-to-RAM) or "standby" (for
- standby suspend) or "freeze" (for suspend type freeze)
- as the system sleep state during system startup with
- the optional capability to repeat N number of times.
- The system is woken from this state using a
- wakeup-capable RTC alarm.
-
- thash_entries= [KNL,NET]
- Set number of hash buckets for TCP connection
-
- thermal.act= [HW,ACPI]
- -1: disable all active trip points in all thermal zones
- <degrees C>: override all lowest active trip points
-
- thermal.crt= [HW,ACPI]
- -1: disable all critical trip points in all thermal zones
- <degrees C>: override all critical trip points
-
- thermal.nocrt= [HW,ACPI]
- Set to disable actions on ACPI thermal zone
- critical and hot trip points.
-
- thermal.off= [HW,ACPI]
- 1: disable ACPI thermal control
-
- thermal.psv= [HW,ACPI]
- -1: disable all passive trip points
- <degrees C>: override all passive trip points to this
- value
-
- thermal.tzp= [HW,ACPI]
- Specify global default ACPI thermal zone polling rate
- <deci-seconds>: poll all this frequency
- 0: no polling (default)
-
- threadirqs [KNL]
- Force threading of all interrupt handlers except those
- marked explicitly IRQF_NO_THREAD.
-
- tmem [KNL,XEN]
- Enable the Transcendent memory driver if built-in.
-
- tmem.cleancache=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the cleancache
- API to send anonymous pages to the hypervisor.
-
- tmem.frontswap=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the frontswap
- API to send swap pages to the hypervisor. If disabled
- the selfballooning and selfshrinking are force disabled.
-
- tmem.selfballooning=0|1 [KNL, XEN]
- Default is on (1). Disable the driving of swap pages
- to the hypervisor.
-
- tmem.selfshrinking=0|1 [KNL, XEN]
- Default is on (1). Partial swapoff that immediately
- transfers pages from Xen hypervisor back to the
- kernel based on different criteria.
-
- topology= [S390]
- Format: {off | on}
- Specify if the kernel should make use of the cpu
- topology information if the hardware supports this.
- The scheduler will make use of this information and
- e.g. base its process migration decisions on it.
- Default is on.
-
- topology_updates= [KNL, PPC, NUMA]
- Format: {off}
- Specify if the kernel should ignore (off)
- topology updates sent by the hypervisor to this
- LPAR.
-
- tp720= [HW,PS2]
-
- tpm_suspend_pcr=[HW,TPM]
- Format: integer pcr id
- Specify that at suspend time, the tpm driver
- should extend the specified pcr with zeros,
- as a workaround for some chips which fail to
- flush the last written pcr on TPM_SaveState.
- This will guarantee that all the other pcrs
- are saved.
-
- trace_buf_size=nn[KMG]
- [FTRACE] will set tracing buffer size on each cpu.
-
- trace_event=[event-list]
- [FTRACE] Set and start specified trace events in order
- to facilitate early boot debugging. The event-list is a
- comma separated list of trace events to enable. See
- also Documentation/trace/events.txt
-
- trace_options=[option-list]
- [FTRACE] Enable or disable tracer options at boot.
- The option-list is a comma delimited list of options
- that can be enabled or disabled just as if you were
- to echo the option name into
-
- /sys/kernel/debug/tracing/trace_options
-
- For example, to enable stacktrace option (to dump the
- stack trace of each event), add to the command line:
-
- trace_options=stacktrace
-
- See also Documentation/trace/ftrace.txt "trace options"
- section.
-
- tp_printk[FTRACE]
- Have the tracepoints sent to printk as well as the
- tracing ring buffer. This is useful for early boot up
- where the system hangs or reboots and does not give the
- option for reading the tracing buffer or performing a
- ftrace_dump_on_oops.
-
- To turn off having tracepoints sent to printk,
- echo 0 > /proc/sys/kernel/tracepoint_printk
- Note, echoing 1 into this file without the
- tracepoint_printk kernel cmdline option has no effect.
-
- ** CAUTION **
-
- Having tracepoints sent to printk() and activating high
- frequency tracepoints such as irq or sched, can cause
- the system to live lock.
-
- traceoff_on_warning
- [FTRACE] enable this option to disable tracing when a
- warning is hit. This turns off "tracing_on". Tracing can
- be enabled again by echoing '1' into the "tracing_on"
- file located in /sys/kernel/debug/tracing/
-
- This option is useful, as it disables the trace before
- the WARNING dump is called, which prevents the trace to
- be filled with content caused by the warning output.
-
- This option can also be set at run time via the sysctl
- option: kernel/traceoff_on_warning
-
- transparent_hugepage=
- [KNL]
- Format: [always|madvise|never]
- Can be used to control the default behavior of the system
- with respect to transparent hugepages.
- See Documentation/vm/transhuge.txt for more details.
-
- tsc= Disable clocksource stability checks for TSC.
- Format: <string>
- [x86] reliable: mark tsc clocksource as reliable, this
- disables clocksource verification at runtime, as well
- as the stability checks done at bootup. Used to enable
- high-resolution timer mode on older hardware, and in
- virtualized environment.
- [x86] noirqtime: Do not use TSC to do irq accounting.
- Used to run time disable IRQ_TIME_ACCOUNTING on any
- platforms where RDTSC is slow and this accounting
- can add overhead.
-
- turbografx.map[2|3]= [HW,JOY]
- TurboGraFX parallel port interface
- Format:
- <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
- See also Documentation/input/joystick-parport.txt
-
- udbg-immortal [PPC] When debugging early kernel crashes that
- happen after console_init() and before a proper
- console driver takes over, this boot options might
- help "seeing" what's going on.
-
- uhash_entries= [KNL,NET]
- Set number of hash buckets for UDP/UDP-Lite connections
-
- uhci-hcd.ignore_oc=
- [USB] Ignore overcurrent events (default N).
- Some badly-designed motherboards generate lots of
- bogus events, for ports that aren't wired to
- anything. Set this parameter to avoid log spamming.
- Note that genuine overcurrent events won't be
- reported either.
-
- unknown_nmi_panic
- [X86] Cause panic on unknown NMI.
-
- usbcore.authorized_default=
- [USB] Default USB device authorization:
- (default -1 = authorized except for wireless USB,
- 0 = not authorized, 1 = authorized)
-
- usbcore.autosuspend=
- [USB] The autosuspend time delay (in seconds) used
- for newly-detected USB devices (default 2). This
- is the time required before an idle device will be
- autosuspended. Devices for which the delay is set
- to a negative value won't be autosuspended at all.
-
- usbcore.usbfs_snoop=
- [USB] Set to log all usbfs traffic (default 0 = off).
-
- usbcore.usbfs_snoop_max=
- [USB] Maximum number of bytes to snoop in each URB
- (default = 65536).
-
- usbcore.blinkenlights=
- [USB] Set to cycle leds on hubs (default 0 = off).
-
- usbcore.old_scheme_first=
- [USB] Start with the old device initialization
- scheme (default 0 = off).
-
- usbcore.usbfs_memory_mb=
- [USB] Memory limit (in MB) for buffers allocated by
- usbfs (default = 16, 0 = max = 2047).
-
- usbcore.use_both_schemes=
- [USB] Try the other device initialization scheme
- if the first one fails (default 1 = enabled).
-
- usbcore.initial_descriptor_timeout=
- [USB] Specifies timeout for the initial 64-byte
- USB_REQ_GET_DESCRIPTOR request in milliseconds
- (default 5000 = 5.0 seconds).
-
- usbcore.nousb [USB] Disable the USB subsystem
-
- usbhid.mousepoll=
- [USBHID] The interval which mice are to be polled at.
-
- usb-storage.delay_use=
- [UMS] The delay in seconds before a new device is
- scanned for Logical Units (default 1).
-
- usb-storage.quirks=
- [UMS] A list of quirks entries to supplement or
- override the built-in unusual_devs list. List
- entries are separated by commas. Each entry has
- the form VID:PID:Flags where VID and PID are Vendor
- and Product ID values (4-digit hex numbers) and
- Flags is a set of characters, each corresponding
- to a common usb-storage quirk flag as follows:
- a = SANE_SENSE (collect more than 18 bytes
- of sense data);
- b = BAD_SENSE (don't collect more than 18
- bytes of sense data);
- c = FIX_CAPACITY (decrease the reported
- device capacity by one sector);
- d = NO_READ_DISC_INFO (don't use
- READ_DISC_INFO command);
- e = NO_READ_CAPACITY_16 (don't use
- READ_CAPACITY_16 command);
- f = NO_REPORT_OPCODES (don't use report opcodes
- command, uas only);
- g = MAX_SECTORS_240 (don't transfer more than
- 240 sectors at a time, uas only);
- h = CAPACITY_HEURISTICS (decrease the
- reported device capacity by one
- sector if the number is odd);
- i = IGNORE_DEVICE (don't bind to this
- device);
- j = NO_REPORT_LUNS (don't use report luns
- command, uas only);
- l = NOT_LOCKABLE (don't try to lock and
- unlock ejectable media);
- m = MAX_SECTORS_64 (don't transfer more
- than 64 sectors = 32 KB at a time);
- n = INITIAL_READ10 (force a retry of the
- initial READ(10) command);
- o = CAPACITY_OK (accept the capacity
- reported by the device);
- p = WRITE_CACHE (the device cache is ON
- by default);
- r = IGNORE_RESIDUE (the device reports
- bogus residue values);
- s = SINGLE_LUN (the device has only one
- Logical Unit);
- t = NO_ATA_1X (don't allow ATA(12) and ATA(16)
- commands, uas only);
- u = IGNORE_UAS (don't bind to the uas driver);
- w = NO_WP_DETECT (don't test whether the
- medium is write-protected).
- y = ALWAYS_SYNC (issue a SYNCHRONIZE_CACHE
- even if the device claims no cache)
- Example: quirks=0419:aaf5:rl,0421:0433:rc
-
- user_debug= [KNL,ARM]
- Format: <int>
- See arch/arm/Kconfig.debug help text.
- 1 - undefined instruction events
- 2 - system calls
- 4 - invalid data aborts
- 8 - SIGSEGV faults
- 16 - SIGBUS faults
- Example: user_debug=31
-
- userpte=
- [X86] Flags controlling user PTE allocations.
-
- nohigh = do not allocate PTE pages in
- HIGHMEM regardless of setting
- of CONFIG_HIGHPTE.
-
- vdso= [X86,SH]
- On X86_32, this is an alias for vdso32=. Otherwise:
-
- vdso=1: enable VDSO (the default)
- vdso=0: disable VDSO mapping
-
- vdso32= [X86] Control the 32-bit vDSO
- vdso32=1: enable 32-bit VDSO
- vdso32=0 or vdso32=2: disable 32-bit VDSO
-
- See the help text for CONFIG_COMPAT_VDSO for more
- details. If CONFIG_COMPAT_VDSO is set, the default is
- vdso32=0; otherwise, the default is vdso32=1.
-
- For compatibility with older kernels, vdso32=2 is an
- alias for vdso32=0.
-
- Try vdso32=0 if you encounter an error that says:
- dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
-
- vector= [IA-64,SMP]
- vector=percpu: enable percpu vector domain
-
- video= [FB] Frame buffer configuration
- See Documentation/fb/modedb.txt.
-
- video.brightness_switch_enabled= [0,1]
- If set to 1, on receiving an ACPI notify event
- generated by hotkey, video driver will adjust brightness
- level and then send out the event to user space through
- the allocated input device; If set to 0, video driver
- will only send out the event without touching backlight
- brightness level.
- default: 1
-
- virtio_mmio.device=
- [VMMIO] Memory mapped virtio (platform) device.
-
- <size>@<baseaddr>:<irq>[:<id>]
- where:
- <size> := size (can use standard suffixes
- like K, M and G)
- <baseaddr> := physical base address
- <irq> := interrupt number (as passed to
- request_irq())
- <id> := (optional) platform device id
- example:
- virtio_mmio.device=1K@0x100b0000:48:7
-
- Can be used multiple times for multiple devices.
-
- vga= [BOOT,X86-32] Select a particular video mode
- See Documentation/x86/boot.txt and
- Documentation/svga.txt.
- Use vga=ask for menu.
- This is actually a boot loader parameter; the value is
- passed to the kernel using a special protocol.
-
- vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
- size of <nn>. This can be used to increase the
- minimum size (128MB on x86). It can also be used to
- decrease the size and leave more room for directly
- mapped kernel RAM.
-
- vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
- Format: <command>
-
- vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
- Format: <command>
-
- vmpoff= [KNL,S390] Perform z/VM CP command after power off.
- Format: <command>
-
- vsyscall= [X86-64]
- Controls the behavior of vsyscalls (i.e. calls to
- fixed addresses of 0xffffffffff600x00 from legacy
- code). Most statically-linked binaries and older
- versions of glibc use these calls. Because these
- functions are at fixed addresses, they make nice
- targets for exploits that can control RIP.
-
- emulate [default] Vsyscalls turn into traps and are
- emulated reasonably safely.
-
- native Vsyscalls are native syscall instructions.
- This is a little bit faster than trapping
- and makes a few dynamic recompilers work
- better than they would in emulation mode.
- It also makes exploits much easier to write.
-
- none Vsyscalls don't work at all. This makes
- them quite hard to use for exploits but
- might break your system.
-
- vt.color= [VT] Default text color.
- Format: 0xYX, X = foreground, Y = background.
- Default: 0x07 = light gray on black.
-
- vt.cur_default= [VT] Default cursor shape.
- Format: 0xCCBBAA, where AA, BB, and CC are the same as
- the parameters of the <Esc>[?A;B;Cc escape sequence;
- see VGA-softcursor.txt. Default: 2 = underline.
-
- vt.default_blu= [VT]
- Format: <blue0>,<blue1>,<blue2>,...,<blue15>
- Change the default blue palette of the console.
- This is a 16-member array composed of values
- ranging from 0-255.
-
- vt.default_grn= [VT]
- Format: <green0>,<green1>,<green2>,...,<green15>
- Change the default green palette of the console.
- This is a 16-member array composed of values
- ranging from 0-255.
-
- vt.default_red= [VT]
- Format: <red0>,<red1>,<red2>,...,<red15>
- Change the default red palette of the console.
- This is a 16-member array composed of values
- ranging from 0-255.
-
- vt.default_utf8=
- [VT]
- Format=<0|1>
- Set system-wide default UTF-8 mode for all tty's.
- Default is 1, i.e. UTF-8 mode is enabled for all
- newly opened terminals.
-
- vt.global_cursor_default=
- [VT]
- Format=<-1|0|1>
- Set system-wide default for whether a cursor
- is shown on new VTs. Default is -1,
- i.e. cursors will be created by default unless
- overridden by individual drivers. 0 will hide
- cursors, 1 will display them.
-
- vt.italic= [VT] Default color for italic text; 0-15.
- Default: 2 = green.
-
- vt.underline= [VT] Default color for underlined text; 0-15.
- Default: 3 = cyan.
-
- watchdog timers [HW,WDT] For information on watchdog timers,
- see Documentation/watchdog/watchdog-parameters.txt
- or other driver-specific files in the
- Documentation/watchdog/ directory.
-
- workqueue.watchdog_thresh=
- If CONFIG_WQ_WATCHDOG is configured, workqueue can
- warn stall conditions and dump internal state to
- help debugging. 0 disables workqueue stall
- detection; otherwise, it's the stall threshold
- duration in seconds. The default value is 30 and
- it can be updated at runtime by writing to the
- corresponding sysfs file.
-
- workqueue.disable_numa
- By default, all work items queued to unbound
- workqueues are affine to the NUMA nodes they're
- issued on, which results in better behavior in
- general. If NUMA affinity needs to be disabled for
- whatever reason, this option can be used. Note
- that this also can be controlled per-workqueue for
- workqueues visible under /sys/bus/workqueue/.
-
- workqueue.power_efficient
- Per-cpu workqueues are generally preferred because
- they show better performance thanks to cache
- locality; unfortunately, per-cpu workqueues tend to
- be more power hungry than unbound workqueues.
-
- Enabling this makes the per-cpu workqueues which
- were observed to contribute significantly to power
- consumption unbound, leading to measurably lower
- power usage at the cost of small performance
- overhead.
-
- The default value of this parameter is determined by
- the config option CONFIG_WQ_POWER_EFFICIENT_DEFAULT.
-
- workqueue.debug_force_rr_cpu
- Workqueue used to implicitly guarantee that work
- items queued without explicit CPU specified are put
- on the local CPU. This guarantee is no longer true
- and while local CPU is still preferred work items
- may be put on foreign CPUs. This debug option
- forces round-robin CPU selection to flush out
- usages which depend on the now broken guarantee.
- When enabled, memory and cache locality will be
- impacted.
-
- x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
- default x2apic cluster mode on platforms
- supporting x2apic.
-
- x86_intel_mid_timer= [X86-32,APBT]
- Choose timer option for x86 Intel MID platform.
- Two valid options are apbt timer only and lapic timer
- plus one apbt timer for broadcast timer.
- x86_intel_mid_timer=apbt_only | lapic_and_apbt
-
- xen_512gb_limit [KNL,X86-64,XEN]
- Restricts the kernel running paravirtualized under Xen
- to use only up to 512 GB of RAM. The reason to do so is
- crash analysis tools and Xen tools for doing domain
- save/restore/migration must be enabled to handle larger
- domains.
-
- xen_emul_unplug= [HW,X86,XEN]
- Unplug Xen emulated devices
- Format: [unplug0,][unplug1]
- ide-disks -- unplug primary master IDE devices
- aux-ide-disks -- unplug non-primary-master IDE devices
- nics -- unplug network devices
- all -- unplug all emulated devices (NICs and IDE disks)
- unnecessary -- unplugging emulated devices is
- unnecessary even if the host did not respond to
- the unplug protocol
- never -- do not unplug even if version check succeeds
-
- xen_nopvspin [X86,XEN]
- Disables the ticketlock slowpath using Xen PV
- optimizations.
-
- xen_nopv [X86]
- Disables the PV optimizations forcing the HVM guest to
- run as generic HVM guest with no PV drivers.
-
- xirc2ps_cs= [NET,PCMCIA]
- Format:
- <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
-
-------------------------
-
-Todo
-----
-
- Add more DRM drivers.
+++ /dev/null
-RAID arrays
-===========
-
-Boot time assembly of RAID arrays
----------------------------------
-
-Tools that manage md devices can be found at
- http://www.kernel.org/pub/linux/utils/raid/
-
-
-You can boot with your md device with the following kernel command
-lines:
-
-for old raid arrays without persistent superblocks::
-
- md=<md device no.>,<raid level>,<chunk size factor>,<fault level>,dev0,dev1,...,devn
-
-for raid arrays with persistent superblocks::
-
- md=<md device no.>,dev0,dev1,...,devn
-
-or, to assemble a partitionable array::
-
- md=d<md device no.>,dev0,dev1,...,devn
-
-``md device no.``
-+++++++++++++++++
-
-The number of the md device
-
-================= =========
-``md device no.`` device
-================= =========
- 0 md0
- 1 md1
- 2 md2
- 3 md3
- 4 md4
-================= =========
-
-``raid level``
-++++++++++++++
-
-level of the RAID array
-
-=============== =============
-``raid level`` level
-=============== =============
--1 linear mode
-0 striped mode
-=============== =============
-
-other modes are only supported with persistent super blocks
-
-``chunk size factor``
-+++++++++++++++++++++
-
-(raid-0 and raid-1 only)
-
-Set the chunk size as 4k << n.
-
-``fault level``
-+++++++++++++++
-
-Totally ignored
-
-``dev0`` to ``devn``
-++++++++++++++++++++
-
-e.g. ``/dev/hda1``, ``/dev/hdc1``, ``/dev/sda1``, ``/dev/sdb1``
-
-A possible loadlin line (Harald Hoyer <HarryH@Royal.Net>) looks like this::
-
- e:\loadlin\loadlin e:\zimage root=/dev/md0 md=0,0,4,0,/dev/hdb2,/dev/hdc3 ro
-
-
-Boot time autodetection of RAID arrays
---------------------------------------
-
-When md is compiled into the kernel (not as module), partitions of
-type 0xfd are scanned and automatically assembled into RAID arrays.
-This autodetection may be suppressed with the kernel parameter
-``raid=noautodetect``. As of kernel 2.6.9, only drives with a type 0
-superblock can be autodetected and run at boot time.
-
-The kernel parameter ``raid=partitionable`` (or ``raid=part``) means
-that all auto-detected arrays are assembled as partitionable.
-
-Boot time assembly of degraded/dirty arrays
--------------------------------------------
-
-If a raid5 or raid6 array is both dirty and degraded, it could have
-undetectable data corruption. This is because the fact that it is
-``dirty`` means that the parity cannot be trusted, and the fact that it
-is degraded means that some datablocks are missing and cannot reliably
-be reconstructed (due to no parity).
-
-For this reason, md will normally refuse to start such an array. This
-requires the sysadmin to take action to explicitly start the array
-despite possible corruption. This is normally done with::
-
- mdadm --assemble --force ....
-
-This option is not really available if the array has the root
-filesystem on it. In order to support this booting from such an
-array, md supports a module parameter ``start_dirty_degraded`` which,
-when set to 1, bypassed the checks and will allows dirty degraded
-arrays to be started.
-
-So, to boot with a root filesystem of a dirty degraded raid 5 or 6, use::
-
- md-mod.start_dirty_degraded=1
-
-
-Superblock formats
-------------------
-
-The md driver can support a variety of different superblock formats.
-Currently, it supports superblock formats ``0.90.0`` and the ``md-1`` format
-introduced in the 2.5 development series.
-
-The kernel will autodetect which format superblock is being used.
-
-Superblock format ``0`` is treated differently to others for legacy
-reasons - it is the original superblock format.
-
-
-General Rules - apply for all superblock formats
-------------------------------------------------
-
-An array is ``created`` by writing appropriate superblocks to all
-devices.
-
-It is ``assembled`` by associating each of these devices with an
-particular md virtual device. Once it is completely assembled, it can
-be accessed.
-
-An array should be created by a user-space tool. This will write
-superblocks to all devices. It will usually mark the array as
-``unclean``, or with some devices missing so that the kernel md driver
-can create appropriate redundancy (copying in raid 1, parity
-calculation in raid 4/5).
-
-When an array is assembled, it is first initialized with the
-SET_ARRAY_INFO ioctl. This contains, in particular, a major and minor
-version number. The major version number selects which superblock
-format is to be used. The minor number might be used to tune handling
-of the format, such as suggesting where on each device to look for the
-superblock.
-
-Then each device is added using the ADD_NEW_DISK ioctl. This
-provides, in particular, a major and minor number identifying the
-device to add.
-
-The array is started with the RUN_ARRAY ioctl.
-
-Once started, new devices can be added. They should have an
-appropriate superblock written to them, and then be passed in with
-ADD_NEW_DISK.
-
-Devices that have failed or are not yet active can be detached from an
-array using HOT_REMOVE_DISK.
-
-
-Specific Rules that apply to format-0 super block arrays, and arrays with no superblock (non-persistent)
---------------------------------------------------------------------------------------------------------
-
-An array can be ``created`` by describing the array (level, chunksize
-etc) in a SET_ARRAY_INFO ioctl. This must have ``major_version==0`` and
-``raid_disks != 0``.
-
-Then uninitialized devices can be added with ADD_NEW_DISK. The
-structure passed to ADD_NEW_DISK must specify the state of the device
-and its role in the array.
-
-Once started with RUN_ARRAY, uninitialized spares can be added with
-HOT_ADD_DISK.
-
-
-MD devices in sysfs
--------------------
-
-md devices appear in sysfs (``/sys``) as regular block devices,
-e.g.::
-
- /sys/block/md0
-
-Each ``md`` device will contain a subdirectory called ``md`` which
-contains further md-specific information about the device.
-
-All md devices contain:
-
- level
- a text file indicating the ``raid level``. e.g. raid0, raid1,
- raid5, linear, multipath, faulty.
- If no raid level has been set yet (array is still being
- assembled), the value will reflect whatever has been written
- to it, which may be a name like the above, or may be a number
- such as ``0``, ``5``, etc.
-
- raid_disks
- a text file with a simple number indicating the number of devices
- in a fully functional array. If this is not yet known, the file
- will be empty. If an array is being resized this will contain
- the new number of devices.
- Some raid levels allow this value to be set while the array is
- active. This will reconfigure the array. Otherwise it can only
- be set while assembling an array.
- A change to this attribute will not be permitted if it would
- reduce the size of the array. To reduce the number of drives
- in an e.g. raid5, the array size must first be reduced by
- setting the ``array_size`` attribute.
-
- chunk_size
- This is the size in bytes for ``chunks`` and is only relevant to
- raid levels that involve striping (0,4,5,6,10). The address space
- of the array is conceptually divided into chunks and consecutive
- chunks are striped onto neighbouring devices.
- The size should be at least PAGE_SIZE (4k) and should be a power
- of 2. This can only be set while assembling an array
-
- layout
- The ``layout`` for the array for the particular level. This is
- simply a number that is interpretted differently by different
- levels. It can be written while assembling an array.
-
- array_size
- This can be used to artificially constrain the available space in
- the array to be less than is actually available on the combined
- devices. Writing a number (in Kilobytes) which is less than
- the available size will set the size. Any reconfiguration of the
- array (e.g. adding devices) will not cause the size to change.
- Writing the word ``default`` will cause the effective size of the
- array to be whatever size is actually available based on
- ``level``, ``chunk_size`` and ``component_size``.
-
- This can be used to reduce the size of the array before reducing
- the number of devices in a raid4/5/6, or to support external
- metadata formats which mandate such clipping.
-
- reshape_position
- This is either ``none`` or a sector number within the devices of
- the array where ``reshape`` is up to. If this is set, the three
- attributes mentioned above (raid_disks, chunk_size, layout) can
- potentially have 2 values, an old and a new value. If these
- values differ, reading the attribute returns::
-
- new (old)
-
- and writing will effect the ``new`` value, leaving the ``old``
- unchanged.
-
- component_size
- For arrays with data redundancy (i.e. not raid0, linear, faulty,
- multipath), all components must be the same size - or at least
- there must a size that they all provide space for. This is a key
- part or the geometry of the array. It is measured in sectors
- and can be read from here. Writing to this value may resize
- the array if the personality supports it (raid1, raid5, raid6),
- and if the component drives are large enough.
-
- metadata_version
- This indicates the format that is being used to record metadata
- about the array. It can be 0.90 (traditional format), 1.0, 1.1,
- 1.2 (newer format in varying locations) or ``none`` indicating that
- the kernel isn't managing metadata at all.
- Alternately it can be ``external:`` followed by a string which
- is set by user-space. This indicates that metadata is managed
- by a user-space program. Any device failure or other event that
- requires a metadata update will cause array activity to be
- suspended until the event is acknowledged.
-
- resync_start
- The point at which resync should start. If no resync is needed,
- this will be a very large number (or ``none`` since 2.6.30-rc1). At
- array creation it will default to 0, though starting the array as
- ``clean`` will set it much larger.
-
- new_dev
- This file can be written but not read. The value written should
- be a block device number as major:minor. e.g. 8:0
- This will cause that device to be attached to the array, if it is
- available. It will then appear at md/dev-XXX (depending on the
- name of the device) and further configuration is then possible.
-
- safe_mode_delay
- When an md array has seen no write requests for a certain period
- of time, it will be marked as ``clean``. When another write
- request arrives, the array is marked as ``dirty`` before the write
- commences. This is known as ``safe_mode``.
- The ``certain period`` is controlled by this file which stores the
- period as a number of seconds. The default is 200msec (0.200).
- Writing a value of 0 disables safemode.
-
- array_state
- This file contains a single word which describes the current
- state of the array. In many cases, the state can be set by
- writing the word for the desired state, however some states
- cannot be explicitly set, and some transitions are not allowed.
-
- Select/poll works on this file. All changes except between
- Active_idle and active (which can be frequent and are not
- very interesting) are notified. active->active_idle is
- reported if the metadata is externally managed.
-
- clear
- No devices, no size, no level
-
- Writing is equivalent to STOP_ARRAY ioctl
-
- inactive
- May have some settings, but array is not active
- all IO results in error
-
- When written, doesn't tear down array, but just stops it
-
- suspended (not supported yet)
- All IO requests will block. The array can be reconfigured.
-
- Writing this, if accepted, will block until array is quiessent
-
- readonly
- no resync can happen. no superblocks get written.
-
- Write requests fail
-
- read-auto
- like readonly, but behaves like ``clean`` on a write request.
-
- clean
- no pending writes, but otherwise active.
-
- When written to inactive array, starts without resync
-
- If a write request arrives then
- if metadata is known, mark ``dirty`` and switch to ``active``.
- if not known, block and switch to write-pending
-
- If written to an active array that has pending writes, then fails.
- active
- fully active: IO and resync can be happening.
- When written to inactive array, starts with resync
-
- write-pending
- clean, but writes are blocked waiting for ``active`` to be written.
-
- active-idle
- like active, but no writes have been seen for a while (safe_mode_delay).
-
- bitmap/location
- This indicates where the write-intent bitmap for the array is
- stored.
-
- It can be one of ``none``, ``file`` or ``[+-]N``.
- ``file`` may later be extended to ``file:/file/name``
- ``[+-]N`` means that many sectors from the start of the metadata.
-
- This is replicated on all devices. For arrays with externally
- managed metadata, the offset is from the beginning of the
- device.
-
- bitmap/chunksize
- The size, in bytes, of the chunk which will be represented by a
- single bit. For RAID456, it is a portion of an individual
- device. For RAID10, it is a portion of the array. For RAID1, it
- is both (they come to the same thing).
-
- bitmap/time_base
- The time, in seconds, between looking for bits in the bitmap to
- be cleared. In the current implementation, a bit will be cleared
- between 2 and 3 times ``time_base`` after all the covered blocks
- are known to be in-sync.
-
- bitmap/backlog
- When write-mostly devices are active in a RAID1, write requests
- to those devices proceed in the background - the filesystem (or
- other user of the device) does not have to wait for them.
- ``backlog`` sets a limit on the number of concurrent background
- writes. If there are more than this, new writes will by
- synchronous.
-
- bitmap/metadata
- This can be either ``internal`` or ``external``.
-
- ``internal``
- is the default and means the metadata for the bitmap
- is stored in the first 256 bytes of the allocated space and is
- managed by the md module.
-
- ``external``
- means that bitmap metadata is managed externally to
- the kernel (i.e. by some userspace program)
-
- bitmap/can_clear
- This is either ``true`` or ``false``. If ``true``, then bits in the
- bitmap will be cleared when the corresponding blocks are thought
- to be in-sync. If ``false``, bits will never be cleared.
- This is automatically set to ``false`` if a write happens on a
- degraded array, or if the array becomes degraded during a write.
- When metadata is managed externally, it should be set to true
- once the array becomes non-degraded, and this fact has been
- recorded in the metadata.
-
-
-
-
-As component devices are added to an md array, they appear in the ``md``
-directory as new directories named::
-
- dev-XXX
-
-where ``XXX`` is a name that the kernel knows for the device, e.g. hdb1.
-Each directory contains:
-
- block
- a symlink to the block device in /sys/block, e.g.::
-
- /sys/block/md0/md/dev-hdb1/block -> ../../../../block/hdb/hdb1
-
- super
- A file containing an image of the superblock read from, or
- written to, that device.
-
- state
- A file recording the current state of the device in the array
- which can be a comma separated list of:
-
- faulty
- device has been kicked from active use due to
- a detected fault, or it has unacknowledged bad
- blocks
-
- in_sync
- device is a fully in-sync member of the array
-
- writemostly
- device will only be subject to read
- requests if there are no other options.
-
- This applies only to raid1 arrays.
-
- blocked
- device has failed, and the failure hasn't been
- acknowledged yet by the metadata handler.
-
- Writes that would write to this device if
- it were not faulty are blocked.
-
- spare
- device is working, but not a full member.
-
- This includes spares that are in the process
- of being recovered to
-
- write_error
- device has ever seen a write error.
-
- want_replacement
- device is (mostly) working but probably
- should be replaced, either due to errors or
- due to user request.
-
- replacement
- device is a replacement for another active
- device with same raid_disk.
-
-
- This list may grow in future.
-
- This can be written to.
-
- Writing ``faulty`` simulates a failure on the device.
-
- Writing ``remove`` removes the device from the array.
-
- Writing ``writemostly`` sets the writemostly flag.
-
- Writing ``-writemostly`` clears the writemostly flag.
-
- Writing ``blocked`` sets the ``blocked`` flag.
-
- Writing ``-blocked`` clears the ``blocked`` flags and allows writes
- to complete and possibly simulates an error.
-
- Writing ``in_sync`` sets the in_sync flag.
-
- Writing ``write_error`` sets writeerrorseen flag.
-
- Writing ``-write_error`` clears writeerrorseen flag.
-
- Writing ``want_replacement`` is allowed at any time except to a
- replacement device or a spare. It sets the flag.
-
- Writing ``-want_replacement`` is allowed at any time. It clears
- the flag.
-
- Writing ``replacement`` or ``-replacement`` is only allowed before
- starting the array. It sets or clears the flag.
-
-
- This file responds to select/poll. Any change to ``faulty``
- or ``blocked`` causes an event.
-
- errors
- An approximate count of read errors that have been detected on
- this device but have not caused the device to be evicted from
- the array (either because they were corrected or because they
- happened while the array was read-only). When using version-1
- metadata, this value persists across restarts of the array.
-
- This value can be written while assembling an array thus
- providing an ongoing count for arrays with metadata managed by
- userspace.
-
- slot
- This gives the role that the device has in the array. It will
- either be ``none`` if the device is not active in the array
- (i.e. is a spare or has failed) or an integer less than the
- ``raid_disks`` number for the array indicating which position
- it currently fills. This can only be set while assembling an
- array. A device for which this is set is assumed to be working.
-
- offset
- This gives the location in the device (in sectors from the
- start) where data from the array will be stored. Any part of
- the device before this offset is not touched, unless it is
- used for storing metadata (Formats 1.1 and 1.2).
-
- size
- The amount of the device, after the offset, that can be used
- for storage of data. This will normally be the same as the
- component_size. This can be written while assembling an
- array. If a value less than the current component_size is
- written, it will be rejected.
-
- recovery_start
- When the device is not ``in_sync``, this records the number of
- sectors from the start of the device which are known to be
- correct. This is normally zero, but during a recovery
- operation it will steadily increase, and if the recovery is
- interrupted, restoring this value can cause recovery to
- avoid repeating the earlier blocks. With v1.x metadata, this
- value is saved and restored automatically.
-
- This can be set whenever the device is not an active member of
- the array, either before the array is activated, or before
- the ``slot`` is set.
-
- Setting this to ``none`` is equivalent to setting ``in_sync``.
- Setting to any other value also clears the ``in_sync`` flag.
-
- bad_blocks
- This gives the list of all known bad blocks in the form of
- start address and length (in sectors respectively). If output
- is too big to fit in a page, it will be truncated. Writing
- ``sector length`` to this file adds new acknowledged (i.e.
- recorded to disk safely) bad blocks.
-
- unacknowledged_bad_blocks
- This gives the list of known-but-not-yet-saved-to-disk bad
- blocks in the same form of ``bad_blocks``. If output is too big
- to fit in a page, it will be truncated. Writing to this file
- adds bad blocks without acknowledging them. This is largely
- for testing.
-
-
-
-An active md device will also contain an entry for each active device
-in the array. These are named::
-
- rdNN
-
-where ``NN`` is the position in the array, starting from 0.
-So for a 3 drive array there will be rd0, rd1, rd2.
-These are symbolic links to the appropriate ``dev-XXX`` entry.
-Thus, for example::
-
- cat /sys/block/md*/md/rd*/state
-
-will show ``in_sync`` on every line.
-
-
-
-Active md devices for levels that support data redundancy (1,4,5,6,10)
-also have
-
- sync_action
- a text file that can be used to monitor and control the rebuild
- process. It contains one word which can be one of:
-
- resync
- redundancy is being recalculated after unclean
- shutdown or creation
-
- recover
- a hot spare is being built to replace a
- failed/missing device
-
- idle
- nothing is happening
- check
- A full check of redundancy was requested and is
- happening. This reads all blocks and checks
- them. A repair may also happen for some raid
- levels.
-
- repair
- A full check and repair is happening. This is
- similar to ``resync``, but was requested by the
- user, and the write-intent bitmap is NOT used to
- optimise the process.
-
- This file is writable, and each of the strings that could be
- read are meaningful for writing.
-
- ``idle`` will stop an active resync/recovery etc. There is no
- guarantee that another resync/recovery may not be automatically
- started again, though some event will be needed to trigger
- this.
-
- ``resync`` or ``recovery`` can be used to restart the
- corresponding operation if it was stopped with ``idle``.
-
- ``check`` and ``repair`` will start the appropriate process
- providing the current state is ``idle``.
-
- This file responds to select/poll. Any important change in the value
- triggers a poll event. Sometimes the value will briefly be
- ``recover`` if a recovery seems to be needed, but cannot be
- achieved. In that case, the transition to ``recover`` isn't
- notified, but the transition away is.
-
- degraded
- This contains a count of the number of devices by which the
- arrays is degraded. So an optimal array will show ``0``. A
- single failed/missing drive will show ``1``, etc.
-
- This file responds to select/poll, any increase or decrease
- in the count of missing devices will trigger an event.
-
- mismatch_count
- When performing ``check`` and ``repair``, and possibly when
- performing ``resync``, md will count the number of errors that are
- found. The count in ``mismatch_cnt`` is the number of sectors
- that were re-written, or (for ``check``) would have been
- re-written. As most raid levels work in units of pages rather
- than sectors, this may be larger than the number of actual errors
- by a factor of the number of sectors in a page.
-
- bitmap_set_bits
- If the array has a write-intent bitmap, then writing to this
- attribute can set bits in the bitmap, indicating that a resync
- would need to check the corresponding blocks. Either individual
- numbers or start-end pairs can be written. Multiple numbers
- can be separated by a space.
-
- Note that the numbers are ``bit`` numbers, not ``block`` numbers.
- They should be scaled by the bitmap_chunksize.
-
- sync_speed_min, sync_speed_max
- This are similar to ``/proc/sys/dev/raid/speed_limit_{min,max}``
- however they only apply to the particular array.
-
- If no value has been written to these, or if the word ``system``
- is written, then the system-wide value is used. If a value,
- in kibibytes-per-second is written, then it is used.
-
- When the files are read, they show the currently active value
- followed by ``(local)`` or ``(system)`` depending on whether it is
- a locally set or system-wide value.
-
- sync_completed
- This shows the number of sectors that have been completed of
- whatever the current sync_action is, followed by the number of
- sectors in total that could need to be processed. The two
- numbers are separated by a ``/`` thus effectively showing one
- value, a fraction of the process that is complete.
-
- A ``select`` on this attribute will return when resync completes,
- when it reaches the current sync_max (below) and possibly at
- other times.
-
- sync_speed
- This shows the current actual speed, in K/sec, of the current
- sync_action. It is averaged over the last 30 seconds.
-
- suspend_lo, suspend_hi
- The two values, given as numbers of sectors, indicate a range
- within the array where IO will be blocked. This is currently
- only supported for raid4/5/6.
-
- sync_min, sync_max
- The two values, given as numbers of sectors, indicate a range
- within the array where ``check``/``repair`` will operate. Must be
- a multiple of chunk_size. When it reaches ``sync_max`` it will
- pause, rather than complete.
- You can use ``select`` or ``poll`` on ``sync_completed`` to wait for
- that number to reach sync_max. Then you can either increase
- ``sync_max``, or can write ``idle`` to ``sync_action``.
-
- The value of ``max`` for ``sync_max`` effectively disables the limit.
- When a resync is active, the value can only ever be increased,
- never decreased.
- The value of ``0`` is the minimum for ``sync_min``.
-
-
-
-Each active md device may also have attributes specific to the
-personality module that manages it.
-These are specific to the implementation of the module and could
-change substantially if the implementation changes.
-
-These currently include:
-
- stripe_cache_size (currently raid5 only)
- number of entries in the stripe cache. This is writable, but
- there are upper and lower limits (32768, 17). Default is 256.
-
- strip_cache_active (currently raid5 only)
- number of active entries in the stripe cache
-
- preread_bypass_threshold (currently raid5 only)
- number of times a stripe requiring preread will be bypassed by
- a stripe that does not require preread. For fairness defaults
- to 1. Setting this to 0 disables bypass accounting and
- requires preread stripes to wait until all full-width stripe-
- writes are complete. Valid values are 0 to stripe_cache_size.
+++ /dev/null
-Mono(tm) Binary Kernel Support for Linux
------------------------------------------
-
-To configure Linux to automatically execute Mono-based .NET binaries
-(in the form of .exe files) without the need to use the mono CLR
-wrapper, you can use the BINFMT_MISC kernel support.
-
-This will allow you to execute Mono-based .NET binaries just like any
-other program after you have done the following:
-
-1) You MUST FIRST install the Mono CLR support, either by downloading
- a binary package, a source tarball or by installing from CVS. Binary
- packages for several distributions can be found at:
-
- http://go-mono.com/download.html
-
- Instructions for compiling Mono can be found at:
-
- http://www.go-mono.com/compiling.html
-
- Once the Mono CLR support has been installed, just check that
- ``/usr/bin/mono`` (which could be located elsewhere, for example
- ``/usr/local/bin/mono``) is working.
-
-2) You have to compile BINFMT_MISC either as a module or into
- the kernel (``CONFIG_BINFMT_MISC``) and set it up properly.
- If you choose to compile it as a module, you will have
- to insert it manually with modprobe/insmod, as kmod
- cannot be easily supported with binfmt_misc.
- Read the file ``binfmt_misc.txt`` in this directory to know
- more about the configuration process.
-
-3) Add the following entries to ``/etc/rc.local`` or similar script
- to be run at system startup::
-
- # Insert BINFMT_MISC module into the kernel
- if [ ! -e /proc/sys/fs/binfmt_misc/register ]; then
- /sbin/modprobe binfmt_misc
- # Some distributions, like Fedora Core, perform
- # the following command automatically when the
- # binfmt_misc module is loaded into the kernel
- # or during normal boot up (systemd-based systems).
- # Thus, it is possible that the following line
- # is not needed at all.
- mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
- fi
-
- # Register support for .NET CLR binaries
- if [ -e /proc/sys/fs/binfmt_misc/register ]; then
- # Replace /usr/bin/mono with the correct pathname to
- # the Mono CLR runtime (usually /usr/local/bin/mono
- # when compiling from sources or CVS).
- echo ':CLR:M::MZ::/usr/bin/mono:' > /proc/sys/fs/binfmt_misc/register
- else
- echo "No binfmt_misc support"
- exit 1
- fi
-
-4) Check that ``.exe`` binaries can be ran without the need of a
- wrapper script, simply by launching the ``.exe`` file directly
- from a command prompt, for example::
-
- /usr/bin/xsd.exe
-
- .. note::
-
- If this fails with a permission denied error, check
- that the ``.exe`` file has execute permissions.
+++ /dev/null
-OOPS tracing
-============
-
-.. note::
-
- ``ksymoops`` is useless on 2.6 or upper. Please use the Oops in its original
- format (from ``dmesg``, etc). Ignore any references in this or other docs to
- "decoding the Oops" or "running it through ksymoops".
- If you post an Oops from 2.6+ that has been run through ``ksymoops``,
- people will just tell you to repost it.
-
-Quick Summary
--------------
-
-Find the Oops and send it to the maintainer of the kernel area that seems to be
-involved with the problem. Don't worry too much about getting the wrong person.
-If you are unsure send it to the person responsible for the code relevant to
-what you were doing. If it occurs repeatably try and describe how to recreate
-it. That's worth even more than the oops.
-
-If you are totally stumped as to whom to send the report, send it to
-linux-kernel@vger.kernel.org. Thanks for your help in making Linux as
-stable as humanly possible.
-
-Where is the Oops?
-----------------------
-
-Normally the Oops text is read from the kernel buffers by klogd and
-handed to ``syslogd`` which writes it to a syslog file, typically
-``/var/log/messages`` (depends on ``/etc/syslog.conf``). Sometimes ``klogd``
-dies, in which case you can run ``dmesg > file`` to read the data from the
-kernel buffers and save it. Or you can ``cat /proc/kmsg > file``, however you
-have to break in to stop the transfer, ``kmsg`` is a "never ending file".
-If the machine has crashed so badly that you cannot enter commands or
-the disk is not available then you have three options :
-
-(1) Hand copy the text from the screen and type it in after the machine
- has restarted. Messy but it is the only option if you have not
- planned for a crash. Alternatively, you can take a picture of
- the screen with a digital camera - not nice, but better than
- nothing. If the messages scroll off the top of the console, you
- may find that booting with a higher resolution (eg, ``vga=791``)
- will allow you to read more of the text. (Caveat: This needs ``vesafb``,
- so won't help for 'early' oopses)
-
-(2) Boot with a serial console (see
- :ref:`Documentation/serial-console.txt <serial_console>`),
- run a null modem to a second machine and capture the output there
- using your favourite communication program. Minicom works well.
-
-(3) Use Kdump (see Documentation/kdump/kdump.txt),
- extract the kernel ring buffer from old memory with using dmesg
- gdbmacro in Documentation/kdump/gdbmacros.txt.
-
-
-Full Information
-----------------
-
-.. note::
-
- the message from Linus below applies to 2.4 kernel. I have preserved it
- for historical reasons, and because some of the information in it still
- applies. Especially, please ignore any references to ksymoops.
-
- ::
-
- From: Linus Torvalds <torvalds@osdl.org>
-
- How to track down an Oops.. [originally a mail to linux-kernel]
-
- The main trick is having 5 years of experience with those pesky oops
- messages ;-)
-
-Actually, there are things you can do that make this easier. I have two
-separate approaches::
-
- gdb /usr/src/linux/vmlinux
- gdb> disassemble <offending_function>
-
-That's the easy way to find the problem, at least if the bug-report is
-well made (like this one was - run through ``ksymoops`` to get the
-information of which function and the offset in the function that it
-happened in).
-
-Oh, it helps if the report happens on a kernel that is compiled with the
-same compiler and similar setups.
-
-The other thing to do is disassemble the "Code:" part of the bug report:
-ksymoops will do this too with the correct tools, but if you don't have
-the tools you can just do a silly program::
-
- char str[] = "\xXX\xXX\xXX...";
- main(){}
-
-and compile it with ``gcc -g`` and then do ``disassemble str`` (where the ``XX``
-stuff are the values reported by the Oops - you can just cut-and-paste
-and do a replace of spaces to ``\x`` - that's what I do, as I'm too lazy
-to write a program to automate this all).
-
-Alternatively, you can use the shell script in ``scripts/decodecode``.
-Its usage is::
-
- decodecode < oops.txt
-
-The hex bytes that follow "Code:" may (in some architectures) have a series
-of bytes that precede the current instruction pointer as well as bytes at and
-following the current instruction pointer. In some cases, one instruction
-byte or word is surrounded by ``<>`` or ``()``, as in ``<86>`` or ``(f00d)``.
-These ``<>`` or ``()`` markings indicate the current instruction pointer.
-
-Example from i386, split into multiple lines for readability::
-
- Code: f9 0f 8d f9 00 00 00 8d 42 0c e8 dd 26 11 c7 a1 60 ea 2b f9 8b 50 08 a1
- 64 ea 2b f9 8d 34 82 8b 1e 85 db 74 6d 8b 15 60 ea 2b f9 <8b> 43 04 39 42 54
- 7e 04 40 89 42 54 8b 43 04 3b 05 00 f6 52 c0
-
-Finally, if you want to see where the code comes from, you can do::
-
- cd /usr/src/linux
- make fs/buffer.s # or whatever file the bug happened in
-
-and then you get a better idea of what happens than with the gdb
-disassembly.
-
-Now, the trick is just then to combine all the data you have: the C
-sources (and general knowledge of what it **should** do), the assembly
-listing and the code disassembly (and additionally the register dump you
-also get from the "oops" message - that can be useful to see **what** the
-corrupted pointers were, and when you have the assembler listing you can
-also match the other registers to whatever C expressions they were used
-for).
-
-Essentially, you just look at what doesn't match (in this case it was the
-"Code" disassembly that didn't match with what the compiler generated).
-Then you need to find out **why** they don't match. Often it's simple - you
-see that the code uses a NULL pointer and then you look at the code and
-wonder how the NULL pointer got there, and if it's a valid thing to do
-you just check against it..
-
-Now, if somebody gets the idea that this is time-consuming and requires
-some small amount of concentration, you're right. Which is why I will
-mostly just ignore any panic reports that don't have the symbol table
-info etc looked up: it simply gets too hard to look it up (I have some
-programs to search for specific patterns in the kernel code segment, and
-sometimes I have been able to look up those kinds of panics too, but
-that really requires pretty good knowledge of the kernel just to be able
-to pick out the right sequences etc..)
-
-**Sometimes** it happens that I just see the disassembled code sequence
-from the panic, and I know immediately where it's coming from. That's when
-I get worried that I've been doing this for too long ;-)
-
- Linus
-
-
----------------------------------------------------------------------------
-
-Notes on Oops tracing with ``klogd``
-------------------------------------
-
-In order to help Linus and the other kernel developers there has been
-substantial support incorporated into ``klogd`` for processing protection
-faults. In order to have full support for address resolution at least
-version 1.3-pl3 of the ``sysklogd`` package should be used.
-
-When a protection fault occurs the ``klogd`` daemon automatically
-translates important addresses in the kernel log messages to their
-symbolic equivalents. This translated kernel message is then
-forwarded through whatever reporting mechanism ``klogd`` is using. The
-protection fault message can be simply cut out of the message files
-and forwarded to the kernel developers.
-
-Two types of address resolution are performed by ``klogd``. The first is
-static translation and the second is dynamic translation. Static
-translation uses the System.map file in much the same manner that
-ksymoops does. In order to do static translation the ``klogd`` daemon
-must be able to find a system map file at daemon initialization time.
-See the klogd man page for information on how ``klogd`` searches for map
-files.
-
-Dynamic address translation is important when kernel loadable modules
-are being used. Since memory for kernel modules is allocated from the
-kernel's dynamic memory pools there are no fixed locations for either
-the start of the module or for functions and symbols in the module.
-
-The kernel supports system calls which allow a program to determine
-which modules are loaded and their location in memory. Using these
-system calls the klogd daemon builds a symbol table which can be used
-to debug a protection fault which occurs in a loadable kernel module.
-
-At the very minimum klogd will provide the name of the module which
-generated the protection fault. There may be additional symbolic
-information available if the developer of the loadable module chose to
-export symbol information from the module.
-
-Since the kernel module environment can be dynamic there must be a
-mechanism for notifying the ``klogd`` daemon when a change in module
-environment occurs. There are command line options available which
-allow klogd to signal the currently executing daemon that symbol
-information should be refreshed. See the ``klogd`` manual page for more
-information.
-
-A patch is included with the sysklogd distribution which modifies the
-``modules-2.0.0`` package to automatically signal klogd whenever a module
-is loaded or unloaded. Applying this patch provides essentially
-seamless support for debugging protection faults which occur with
-kernel loadable modules.
-
-The following is an example of a protection fault in a loadable module
-processed by ``klogd``::
-
- Aug 29 09:51:01 blizard kernel: Unable to handle kernel paging request at virtual address f15e97cc
- Aug 29 09:51:01 blizard kernel: current->tss.cr3 = 0062d000, %cr3 = 0062d000
- Aug 29 09:51:01 blizard kernel: *pde = 00000000
- Aug 29 09:51:01 blizard kernel: Oops: 0002
- Aug 29 09:51:01 blizard kernel: CPU: 0
- Aug 29 09:51:01 blizard kernel: EIP: 0010:[oops:_oops+16/3868]
- Aug 29 09:51:01 blizard kernel: EFLAGS: 00010212
- Aug 29 09:51:01 blizard kernel: eax: 315e97cc ebx: 003a6f80 ecx: 001be77b edx: 00237c0c
- Aug 29 09:51:01 blizard kernel: esi: 00000000 edi: bffffdb3 ebp: 00589f90 esp: 00589f8c
- Aug 29 09:51:01 blizard kernel: ds: 0018 es: 0018 fs: 002b gs: 002b ss: 0018
- Aug 29 09:51:01 blizard kernel: Process oops_test (pid: 3374, process nr: 21, stackpage=00589000)
- Aug 29 09:51:01 blizard kernel: Stack: 315e97cc 00589f98 0100b0b4 bffffed4 0012e38e 00240c64 003a6f80 00000001
- Aug 29 09:51:01 blizard kernel: 00000000 00237810 bfffff00 0010a7fa 00000003 00000001 00000000 bfffff00
- Aug 29 09:51:01 blizard kernel: bffffdb3 bffffed4 ffffffda 0000002b 0007002b 0000002b 0000002b 00000036
- Aug 29 09:51:01 blizard kernel: Call Trace: [oops:_oops_ioctl+48/80] [_sys_ioctl+254/272] [_system_call+82/128]
- Aug 29 09:51:01 blizard kernel: Code: c7 00 05 00 00 00 eb 08 90 90 90 90 90 90 90 90 89 ec 5d c3
-
----------------------------------------------------------------------------
-
-::
-
- Dr. G.W. Wettstein Oncology Research Div. Computing Facility
- Roger Maris Cancer Center INTERNET: greg@wind.rmcc.com
- 820 4th St. N.
- Fargo, ND 58122
- Phone: 701-234-7556
-
-
----------------------------------------------------------------------------
-
-Tainted kernels
----------------
-
-Some oops reports contain the string **'Tainted: '** after the program
-counter. This indicates that the kernel has been tainted by some
-mechanism. The string is followed by a series of position-sensitive
-characters, each representing a particular tainted value.
-
- 1) 'G' if all modules loaded have a GPL or compatible license, 'P' if
- any proprietary module has been loaded. Modules without a
- MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
- insmod as GPL compatible are assumed to be proprietary.
-
- 2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
- modules were loaded normally.
-
- 3) ``S`` if the oops occurred on an SMP kernel running on hardware that
- hasn't been certified as safe to run multiprocessor.
- Currently this occurs only on various Athlons that are not
- SMP capable.
-
- 4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
- modules were unloaded normally.
-
- 5) ``M`` if any processor has reported a Machine Check Exception,
- ``' '`` if no Machine Check Exceptions have occurred.
-
- 6) ``B`` if a page-release function has found a bad page reference or
- some unexpected page flags.
-
- 7) ``U`` if a user or user application specifically requested that the
- Tainted flag be set, ``' '`` otherwise.
-
- 8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
-
- 9) ``A`` if the ACPI table has been overridden.
-
- 10) ``W`` if a warning has previously been issued by the kernel.
- (Though some warnings may set more specific taint flags.)
-
- 11) ``C`` if a staging driver has been loaded.
-
- 12) ``I`` if the kernel is working around a severe bug in the platform
- firmware (BIOS or similar).
-
- 13) ``O`` if an externally-built ("out-of-tree") module has been loaded.
-
- 14) ``E`` if an unsigned module has been loaded in a kernel supporting
- module signature.
-
- 15) ``L`` if a soft lockup has previously occurred on the system.
-
- 16) ``K`` if the kernel has been live patched.
-
-The primary reason for the **'Tainted: '** string is to tell kernel
-debuggers if this is a clean kernel or if anything unusual has
-occurred. Tainting is permanent: even if an offending module is
-unloaded, the tainted value remains to indicate that the kernel is not
-trustworthy.
+++ /dev/null
-Parport
-+++++++
-
-The ``parport`` code provides parallel-port support under Linux. This
-includes the ability to share one port between multiple device
-drivers.
-
-You can pass parameters to the ``parport`` code to override its automatic
-detection of your hardware. This is particularly useful if you want
-to use IRQs, since in general these can't be autoprobed successfully.
-By default IRQs are not used even if they **can** be probed. This is
-because there are a lot of people using the same IRQ for their
-parallel port and a sound card or network card.
-
-The ``parport`` code is split into two parts: generic (which deals with
-port-sharing) and architecture-dependent (which deals with actually
-using the port).
-
-
-Parport as modules
-==================
-
-If you load the `parport`` code as a module, say::
-
- # insmod parport
-
-to load the generic ``parport`` code. You then must load the
-architecture-dependent code with (for example)::
-
- # insmod parport_pc io=0x3bc,0x378,0x278 irq=none,7,auto
-
-to tell the ``parport`` code that you want three PC-style ports, one at
-0x3bc with no IRQ, one at 0x378 using IRQ 7, and one at 0x278 with an
-auto-detected IRQ. Currently, PC-style (``parport_pc``), Sun ``bpp``,
-Amiga, Atari, and MFC3 hardware is supported.
-
-PCI parallel I/O card support comes from ``parport_pc``. Base I/O
-addresses should not be specified for supported PCI cards since they
-are automatically detected.
-
-
-modprobe
---------
-
-If you use modprobe , you will find it useful to add lines as below to a
-configuration file in /etc/modprobe.d/ directory::
-
- alias parport_lowlevel parport_pc
- options parport_pc io=0x378,0x278 irq=7,auto
-
-modprobe will load ``parport_pc`` (with the options ``io=0x378,0x278 irq=7,auto``)
-whenever a parallel port device driver (such as ``lp``) is loaded.
-
-Note that these are example lines only! You shouldn't in general need
-to specify any options to ``parport_pc`` in order to be able to use a
-parallel port.
-
-
-Parport probe [optional]
-------------------------
-
-In 2.2 kernels there was a module called ``parport_probe``, which was used
-for collecting IEEE 1284 device ID information. This has now been
-enhanced and now lives with the IEEE 1284 support. When a parallel
-port is detected, the devices that are connected to it are analysed,
-and information is logged like this::
-
- parport0: Printer, BJC-210 (Canon)
-
-The probe information is available from files in ``/proc/sys/dev/parport/``.
-
-
-Parport linked into the kernel statically
-=========================================
-
-If you compile the ``parport`` code into the kernel, then you can use
-kernel boot parameters to get the same effect. Add something like the
-following to your LILO command line::
-
- parport=0x3bc parport=0x378,7 parport=0x278,auto,nofifo
-
-You can have many ``parport=...`` statements, one for each port you want
-to add. Adding ``parport=0`` to the kernel command-line will disable
-parport support entirely. Adding ``parport=auto`` to the kernel
-command-line will make ``parport`` use any IRQ lines or DMA channels that
-it auto-detects.
-
-
-Files in /proc
-==============
-
-If you have configured the ``/proc`` filesystem into your kernel, you will
-see a new directory entry: ``/proc/sys/dev/parport``. In there will be a
-directory entry for each parallel port for which parport is
-configured. In each of those directories are a collection of files
-describing that parallel port.
-
-The ``/proc/sys/dev/parport`` directory tree looks like::
-
- parport
- |-- default
- | |-- spintime
- | `-- timeslice
- |-- parport0
- | |-- autoprobe
- | |-- autoprobe0
- | |-- autoprobe1
- | |-- autoprobe2
- | |-- autoprobe3
- | |-- devices
- | | |-- active
- | | `-- lp
- | | `-- timeslice
- | |-- base-addr
- | |-- irq
- | |-- dma
- | |-- modes
- | `-- spintime
- `-- parport1
- |-- autoprobe
- |-- autoprobe0
- |-- autoprobe1
- |-- autoprobe2
- |-- autoprobe3
- |-- devices
- | |-- active
- | `-- ppa
- | `-- timeslice
- |-- base-addr
- |-- irq
- |-- dma
- |-- modes
- `-- spintime
-
-.. tabularcolumns:: |p{4.0cm}|p{13.5cm}|
-
-======================= =======================================================
-File Contents
-======================= =======================================================
-``devices/active`` A list of the device drivers using that port. A "+"
- will appear by the name of the device currently using
- the port (it might not appear against any). The
- string "none" means that there are no device drivers
- using that port.
-
-``base-addr`` Parallel port's base address, or addresses if the port
- has more than one in which case they are separated
- with tabs. These values might not have any sensible
- meaning for some ports.
-
-``irq`` Parallel port's IRQ, or -1 if none is being used.
-
-``dma`` Parallel port's DMA channel, or -1 if none is being
- used.
-
-``modes`` Parallel port's hardware modes, comma-separated,
- meaning:
-
- - PCSPP
- PC-style SPP registers are available.
-
- - TRISTATE
- Port is bidirectional.
-
- - COMPAT
- Hardware acceleration for printers is
- available and will be used.
-
- - EPP
- Hardware acceleration for EPP protocol
- is available and will be used.
-
- - ECP
- Hardware acceleration for ECP protocol
- is available and will be used.
-
- - DMA
- DMA is available and will be used.
-
- Note that the current implementation will only take
- advantage of COMPAT and ECP modes if it has an IRQ
- line to use.
-
-``autoprobe`` Any IEEE-1284 device ID information that has been
- acquired from the (non-IEEE 1284.3) device.
-
-``autoprobe[0-3]`` IEEE 1284 device ID information retrieved from
- daisy-chain devices that conform to IEEE 1284.3.
-
-``spintime`` The number of microseconds to busy-loop while waiting
- for the peripheral to respond. You might find that
- adjusting this improves performance, depending on your
- peripherals. This is a port-wide setting, i.e. it
- applies to all devices on a particular port.
-
-``timeslice`` The number of milliseconds that a device driver is
- allowed to keep a port claimed for. This is advisory,
- and driver can ignore it if it must.
-
-``default/*`` The defaults for spintime and timeslice. When a new
- port is registered, it picks up the default spintime.
- When a new device is registered, it picks up the
- default timeslice.
-======================= =======================================================
-
-Device drivers
-==============
-
-Once the parport code is initialised, you can attach device drivers to
-specific ports. Normally this happens automatically; if the lp driver
-is loaded it will create one lp device for each port found. You can
-override this, though, by using parameters either when you load the lp
-driver::
-
- # insmod lp parport=0,2
-
-or on the LILO command line::
-
- lp=parport0 lp=parport2
-
-Both the above examples would inform lp that you want ``/dev/lp0`` to be
-the first parallel port, and /dev/lp1 to be the **third** parallel port,
-with no lp device associated with the second port (parport1). Note
-that this is different to the way older kernels worked; there used to
-be a static association between the I/O port address and the device
-name, so ``/dev/lp0`` was always the port at 0x3bc. This is no longer the
-case - if you only have one port, it will default to being ``/dev/lp0``,
-regardless of base address.
-
-Also:
-
- * If you selected the IEEE 1284 support at compile time, you can say
- ``lp=auto`` on the kernel command line, and lp will create devices
- only for those ports that seem to have printers attached.
-
- * If you give PLIP the ``timid`` parameter, either with ``plip=timid`` on
- the command line, or with ``insmod plip timid=1`` when using modules,
- it will avoid any ports that seem to be in use by other devices.
-
- * IRQ autoprobing works only for a few port types at the moment.
-
-Reporting printer problems with parport
-=======================================
-
-If you are having problems printing, please go through these steps to
-try to narrow down where the problem area is.
-
-When reporting problems with parport, really you need to give all of
-the messages that ``parport_pc`` spits out when it initialises. There are
-several code paths:
-
-- polling
-- interrupt-driven, protocol in software
-- interrupt-driven, protocol in hardware using PIO
-- interrupt-driven, protocol in hardware using DMA
-
-The kernel messages that ``parport_pc`` logs give an indication of which
-code path is being used. (They could be a lot better actually..)
-
-For normal printer protocol, having IEEE 1284 modes enabled or not
-should not make a difference.
-
-To turn off the 'protocol in hardware' code paths, disable
-``CONFIG_PARPORT_PC_FIFO``. Note that when they are enabled they are not
-necessarily **used**; it depends on whether the hardware is available,
-enabled by the BIOS, and detected by the driver.
-
-So, to start with, disable ``CONFIG_PARPORT_PC_FIFO``, and load ``parport_pc``
-with ``irq=none``. See if printing works then. It really should,
-because this is the simplest code path.
-
-If that works fine, try with ``io=0x378 irq=7`` (adjust for your
-hardware), to make it use interrupt-driven in-software protocol.
-
-If **that** works fine, then one of the hardware modes isn't working
-right. Enable ``CONFIG_FIFO`` (no, it isn't a module option,
-and yes, it should be), set the port to ECP mode in the BIOS and note
-the DMA channel, and try with::
-
- io=0x378 irq=7 dma=none (for PIO)
- io=0x378 irq=7 dma=3 (for DMA)
-
-----------
-
-philb@gnu.org
-tim@cyberelk.net
+++ /dev/null
-Ramoops oops/panic logger
-=========================
-
-Sergiu Iordache <sergiu@chromium.org>
-
-Updated: 17 November 2011
-
-Introduction
-------------
-
-Ramoops is an oops/panic logger that writes its logs to RAM before the system
-crashes. It works by logging oopses and panics in a circular buffer. Ramoops
-needs a system with persistent RAM so that the content of that area can
-survive after a restart.
-
-Ramoops concepts
-----------------
-
-Ramoops uses a predefined memory area to store the dump. The start and size
-and type of the memory area are set using three variables:
-
- * ``mem_address`` for the start
- * ``mem_size`` for the size. The memory size will be rounded down to a
- power of two.
- * ``mem_type`` to specifiy if the memory type (default is pgprot_writecombine).
-
-Typically the default value of ``mem_type=0`` should be used as that sets the pstore
-mapping to pgprot_writecombine. Setting ``mem_type=1`` attempts to use
-``pgprot_noncached``, which only works on some platforms. This is because pstore
-depends on atomic operations. At least on ARM, pgprot_noncached causes the
-memory to be mapped strongly ordered, and atomic operations on strongly ordered
-memory are implementation defined, and won't work on many ARMs such as omaps.
-
-The memory area is divided into ``record_size`` chunks (also rounded down to
-power of two) and each oops/panic writes a ``record_size`` chunk of
-information.
-
-Dumping both oopses and panics can be done by setting 1 in the ``dump_oops``
-variable while setting 0 in that variable dumps only the panics.
-
-The module uses a counter to record multiple dumps but the counter gets reset
-on restart (i.e. new dumps after the restart will overwrite old ones).
-
-Ramoops also supports software ECC protection of persistent memory regions.
-This might be useful when a hardware reset was used to bring the machine back
-to life (i.e. a watchdog triggered). In such cases, RAM may be somewhat
-corrupt, but usually it is restorable.
-
-Setting the parameters
-----------------------
-
-Setting the ramoops parameters can be done in several different manners:
-
- A. Use the module parameters (which have the names of the variables described
- as before). For quick debugging, you can also reserve parts of memory during
- boot and then use the reserved memory for ramoops. For example, assuming a
- machine with > 128 MB of memory, the following kernel command line will tell
- the kernel to use only the first 128 MB of memory, and place ECC-protected
- ramoops region at 128 MB boundary::
-
- mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1
-
- B. Use Device Tree bindings, as described in
- ``Documentation/device-tree/bindings/reserved-memory/ramoops.txt``.
- For example::
-
- reserved-memory {
- #address-cells = <2>;
- #size-cells = <2>;
- ranges;
-
- ramoops@8f000000 {
- compatible = "ramoops";
- reg = <0 0x8f000000 0 0x100000>;
- record-size = <0x4000>;
- console-size = <0x4000>;
- };
- };
-
- C. Use a platform device and set the platform data. The parameters can then
- be set through that platform data. An example of doing that is::
-
- #include <linux/pstore_ram.h>
- [...]
-
- static struct ramoops_platform_data ramoops_data = {
- .mem_size = <...>,
- .mem_address = <...>,
- .mem_type = <...>,
- .record_size = <...>,
- .dump_oops = <...>,
- .ecc = <...>,
- };
-
- static struct platform_device ramoops_dev = {
- .name = "ramoops",
- .dev = {
- .platform_data = &ramoops_data,
- },
- };
-
- [... inside a function ...]
- int ret;
-
- ret = platform_device_register(&ramoops_dev);
- if (ret) {
- printk(KERN_ERR "unable to register platform device\n");
- return ret;
- }
-
-You can specify either RAM memory or peripheral devices' memory. However, when
-specifying RAM, be sure to reserve the memory by issuing memblock_reserve()
-very early in the architecture code, e.g.::
-
- #include <linux/memblock.h>
-
- memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
-
-Dump format
------------
-
-The data dump begins with a header, currently defined as ``====`` followed by a
-timestamp and a new line. The dump then continues with the actual data.
-
-Reading the data
-----------------
-
-The dump data can be read from the pstore filesystem. The format for these
-files is ``dmesg-ramoops-N``, where N is the record number in memory. To delete
-a stored record from RAM, simply unlink the respective pstore file.
-
-Persistent function tracing
----------------------------
-
-Persistent function tracing might be useful for debugging software or hardware
-related hangs. The functions call chain log is stored in a ``ftrace-ramoops``
-file. Here is an example of usage::
-
- # mount -t debugfs debugfs /sys/kernel/debug/
- # echo 1 > /sys/kernel/debug/pstore/record_ftrace
- # reboot -f
- [...]
- # mount -t pstore pstore /mnt/
- # tail /mnt/ftrace-ramoops
- 0 ffffffff8101ea64 ffffffff8101bcda native_apic_mem_read <- disconnect_bsp_APIC+0x6a/0xc0
- 0 ffffffff8101ea44 ffffffff8101bcf6 native_apic_mem_write <- disconnect_bsp_APIC+0x86/0xc0
- 0 ffffffff81020084 ffffffff8101a4b5 hpet_disable <- native_machine_shutdown+0x75/0x90
- 0 ffffffff81005f94 ffffffff8101a4bb iommu_shutdown_noop <- native_machine_shutdown+0x7b/0x90
- 0 ffffffff8101a6a1 ffffffff8101a437 native_machine_emergency_restart <- native_machine_restart+0x37/0x40
- 0 ffffffff811f9876 ffffffff8101a73a acpi_reboot <- native_machine_emergency_restart+0xaa/0x1e0
- 0 ffffffff8101a514 ffffffff8101a772 mach_reboot_fixups <- native_machine_emergency_restart+0xe2/0x1e0
- 0 ffffffff811d9c54 ffffffff8101a7a0 __const_udelay <- native_machine_emergency_restart+0x110/0x1e0
- 0 ffffffff811d9c34 ffffffff811d9c80 __delay <- __const_udelay+0x30/0x40
- 0 ffffffff811d9d14 ffffffff811d9c3f delay_tsc <- __delay+0xf/0x20
+++ /dev/null
-.. _serial_console:
-
-Linux Serial Console
-====================
-
-To use a serial port as console you need to compile the support into your
-kernel - by default it is not compiled in. For PC style serial ports
-it's the config option next to menu option:
-
-:menuselection:`Character devices --> Serial drivers --> 8250/16550 and compatible serial support --> Console on 8250/16550 and compatible serial port`
-
-You must compile serial support into the kernel and not as a module.
-
-It is possible to specify multiple devices for console output. You can
-define a new kernel command line option to select which device(s) to
-use for console output.
-
-The format of this option is::
-
- console=device,options
-
- device: tty0 for the foreground virtual console
- ttyX for any other virtual console
- ttySx for a serial port
- lp0 for the first parallel port
- ttyUSB0 for the first USB serial device
-
- options: depend on the driver. For the serial port this
- defines the baudrate/parity/bits/flow control of
- the port, in the format BBBBPNF, where BBBB is the
- speed, P is parity (n/o/e), N is number of bits,
- and F is flow control ('r' for RTS). Default is
- 9600n8. The maximum baudrate is 115200.
-
-You can specify multiple console= options on the kernel command line.
-Output will appear on all of them. The last device will be used when
-you open ``/dev/console``. So, for example::
-
- console=ttyS1,9600 console=tty0
-
-defines that opening ``/dev/console`` will get you the current foreground
-virtual console, and kernel messages will appear on both the VGA
-console and the 2nd serial port (ttyS1 or COM2) at 9600 baud.
-
-Note that you can only define one console per device type (serial, video).
-
-If no console device is specified, the first device found capable of
-acting as a system console will be used. At this time, the system
-first looks for a VGA card and then for a serial port. So if you don't
-have a VGA card in your system the first serial port will automatically
-become the console.
-
-You will need to create a new device to use ``/dev/console``. The official
-``/dev/console`` is now character device 5,1.
-
-(You can also use a network device as a console. See
-``Documentation/networking/netconsole.txt`` for information on that.)
-
-Here's an example that will use ``/dev/ttyS1`` (COM2) as the console.
-Replace the sample values as needed.
-
-1. Create ``/dev/console`` (real console) and ``/dev/tty0`` (master virtual
- console)::
-
- cd /dev
- rm -f console tty0
- mknod -m 622 console c 5 1
- mknod -m 622 tty0 c 4 0
-
-2. LILO can also take input from a serial device. This is a very
- useful option. To tell LILO to use the serial port:
- In lilo.conf (global section)::
-
- serial = 1,9600n8 (ttyS1, 9600 bd, no parity, 8 bits)
-
-3. Adjust to kernel flags for the new kernel,
- again in lilo.conf (kernel section)::
-
- append = "console=ttyS1,9600"
-
-4. Make sure a getty runs on the serial port so that you can login to
- it once the system is done booting. This is done by adding a line
- like this to ``/etc/inittab`` (exact syntax depends on your getty)::
-
- S1:23:respawn:/sbin/getty -L ttyS1 9600 vt100
-
-5. Init and ``/etc/ioctl.save``
-
- Sysvinit remembers its stty settings in a file in ``/etc``, called
- ``/etc/ioctl.save``. REMOVE THIS FILE before using the serial
- console for the first time, because otherwise init will probably
- set the baudrate to 38400 (baudrate of the virtual console).
-
-6. ``/dev/console`` and X
- Programs that want to do something with the virtual console usually
- open ``/dev/console``. If you have created the new ``/dev/console`` device,
- and your console is NOT the virtual console some programs will fail.
- Those are programs that want to access the VT interface, and use
- ``/dev/console instead of /dev/tty0``. Some of those programs are::
-
- Xfree86, svgalib, gpm, SVGATextMode
-
- It should be fixed in modern versions of these programs though.
-
- Note that if you boot without a ``console=`` option (or with
- ``console=/dev/tty0``), ``/dev/console`` is the same as ``/dev/tty0``.
- In that case everything will still work.
-
-7. Thanks
-
- Thanks to Geert Uytterhoeven <geert@linux-m68k.org>
- for porting the patches from 2.1.4x to 2.1.6x for taking care of
- the integration of these patches into m68k, ppc and alpha.
-
-Miquel van Smoorenburg <miquels@cistron.nl>, 11-Jun-2000
+++ /dev/null
-Rules on how to access information in the Linux kernel sysfs
-============================================================
-
-The kernel-exported sysfs exports internal kernel implementation details
-and depends on internal kernel structures and layout. It is agreed upon
-by the kernel developers that the Linux kernel does not provide a stable
-internal API. Therefore, there are aspects of the sysfs interface that
-may not be stable across kernel releases.
-
-To minimize the risk of breaking users of sysfs, which are in most cases
-low-level userspace applications, with a new kernel release, the users
-of sysfs must follow some rules to use an as-abstract-as-possible way to
-access this filesystem. The current udev and HAL programs already
-implement this and users are encouraged to plug, if possible, into the
-abstractions these programs provide instead of accessing sysfs directly.
-
-But if you really do want or need to access sysfs directly, please follow
-the following rules and then your programs should work with future
-versions of the sysfs interface.
-
-- Do not use libsysfs
- It makes assumptions about sysfs which are not true. Its API does not
- offer any abstraction, it exposes all the kernel driver-core
- implementation details in its own API. Therefore it is not better than
- reading directories and opening the files yourself.
- Also, it is not actively maintained, in the sense of reflecting the
- current kernel development. The goal of providing a stable interface
- to sysfs has failed; it causes more problems than it solves. It
- violates many of the rules in this document.
-
-- sysfs is always at ``/sys``
- Parsing ``/proc/mounts`` is a waste of time. Other mount points are a
- system configuration bug you should not try to solve. For test cases,
- possibly support a ``SYSFS_PATH`` environment variable to overwrite the
- application's behavior, but never try to search for sysfs. Never try
- to mount it, if you are not an early boot script.
-
-- devices are only "devices"
- There is no such thing like class-, bus-, physical devices,
- interfaces, and such that you can rely on in userspace. Everything is
- just simply a "device". Class-, bus-, physical, ... types are just
- kernel implementation details which should not be expected by
- applications that look for devices in sysfs.
-
- The properties of a device are:
-
- - devpath (``/devices/pci0000:00/0000:00:1d.1/usb2/2-2/2-2:1.0``)
-
- - identical to the DEVPATH value in the event sent from the kernel
- at device creation and removal
- - the unique key to the device at that point in time
- - the kernel's path to the device directory without the leading
- ``/sys``, and always starting with a slash
- - all elements of a devpath must be real directories. Symlinks
- pointing to /sys/devices must always be resolved to their real
- target and the target path must be used to access the device.
- That way the devpath to the device matches the devpath of the
- kernel used at event time.
- - using or exposing symlink values as elements in a devpath string
- is a bug in the application
-
- - kernel name (``sda``, ``tty``, ``0000:00:1f.2``, ...)
-
- - a directory name, identical to the last element of the devpath
- - applications need to handle spaces and characters like ``!`` in
- the name
-
- - subsystem (``block``, ``tty``, ``pci``, ...)
-
- - simple string, never a path or a link
- - retrieved by reading the "subsystem"-link and using only the
- last element of the target path
-
- - driver (``tg3``, ``ata_piix``, ``uhci_hcd``)
-
- - a simple string, which may contain spaces, never a path or a
- link
- - it is retrieved by reading the "driver"-link and using only the
- last element of the target path
- - devices which do not have "driver"-link just do not have a
- driver; copying the driver value in a child device context is a
- bug in the application
-
- - attributes
-
- - the files in the device directory or files below subdirectories
- of the same device directory
- - accessing attributes reached by a symlink pointing to another device,
- like the "device"-link, is a bug in the application
-
- Everything else is just a kernel driver-core implementation detail
- that should not be assumed to be stable across kernel releases.
-
-- Properties of parent devices never belong into a child device.
- Always look at the parent devices themselves for determining device
- context properties. If the device ``eth0`` or ``sda`` does not have a
- "driver"-link, then this device does not have a driver. Its value is empty.
- Never copy any property of the parent-device into a child-device. Parent
- device properties may change dynamically without any notice to the
- child device.
-
-- Hierarchy in a single device tree
- There is only one valid place in sysfs where hierarchy can be examined
- and this is below: ``/sys/devices.``
- It is planned that all device directories will end up in the tree
- below this directory.
-
-- Classification by subsystem
- There are currently three places for classification of devices:
- ``/sys/block,`` ``/sys/class`` and ``/sys/bus.`` It is planned that these will
- not contain any device directories themselves, but only flat lists of
- symlinks pointing to the unified ``/sys/devices`` tree.
- All three places have completely different rules on how to access
- device information. It is planned to merge all three
- classification directories into one place at ``/sys/subsystem``,
- following the layout of the bus directories. All buses and
- classes, including the converted block subsystem, will show up
- there.
- The devices belonging to a subsystem will create a symlink in the
- "devices" directory at ``/sys/subsystem/<name>/devices``,
-
- If ``/sys/subsystem`` exists, ``/sys/bus``, ``/sys/class`` and ``/sys/block``
- can be ignored. If it does not exist, you always have to scan all three
- places, as the kernel is free to move a subsystem from one place to
- the other, as long as the devices are still reachable by the same
- subsystem name.
-
- Assuming ``/sys/class/<subsystem>`` and ``/sys/bus/<subsystem>``, or
- ``/sys/block`` and ``/sys/class/block`` are not interchangeable is a bug in
- the application.
-
-- Block
- The converted block subsystem at ``/sys/class/block`` or
- ``/sys/subsystem/block`` will contain the links for disks and partitions
- at the same level, never in a hierarchy. Assuming the block subsystem to
- contain only disks and not partition devices in the same flat list is
- a bug in the application.
-
-- "device"-link and <subsystem>:<kernel name>-links
- Never depend on the "device"-link. The "device"-link is a workaround
- for the old layout, where class devices are not created in
- ``/sys/devices/`` like the bus devices. If the link-resolving of a
- device directory does not end in ``/sys/devices/``, you can use the
- "device"-link to find the parent devices in ``/sys/devices/``, That is the
- single valid use of the "device"-link; it must never appear in any
- path as an element. Assuming the existence of the "device"-link for
- a device in ``/sys/devices/`` is a bug in the application.
- Accessing ``/sys/class/net/eth0/device`` is a bug in the application.
-
- Never depend on the class-specific links back to the ``/sys/class``
- directory. These links are also a workaround for the design mistake
- that class devices are not created in ``/sys/devices.`` If a device
- directory does not contain directories for child devices, these links
- may be used to find the child devices in ``/sys/class.`` That is the single
- valid use of these links; they must never appear in any path as an
- element. Assuming the existence of these links for devices which are
- real child device directories in the ``/sys/devices`` tree is a bug in
- the application.
-
- It is planned to remove all these links when all class device
- directories live in ``/sys/devices.``
-
-- Position of devices along device chain can change.
- Never depend on a specific parent device position in the devpath,
- or the chain of parent devices. The kernel is free to insert devices into
- the chain. You must always request the parent device you are looking for
- by its subsystem value. You need to walk up the chain until you find
- the device that matches the expected subsystem. Depending on a specific
- position of a parent device or exposing relative paths using ``../`` to
- access the chain of parents is a bug in the application.
-
-- When reading and writing sysfs device attribute files, avoid dependency
- on specific error codes wherever possible. This minimizes coupling to
- the error handling implementation within the kernel.
-
- In general, failures to read or write sysfs device attributes shall
- propagate errors wherever possible. Common errors include, but are not
- limited to:
-
- ``-EIO``: The read or store operation is not supported, typically
- returned by the sysfs system itself if the read or store pointer
- is ``NULL``.
-
- ``-ENXIO``: The read or store operation failed
-
- Error codes will not be changed without good reason, and should a change
- to error codes result in user-space breakage, it will be fixed, or the
- the offending change will be reverted.
-
- Userspace applications can, however, expect the format and contents of
- the attribute files to remain consistent in the absence of a version
- attribute change in the context of a given attribute.
+++ /dev/null
-Linux Magic System Request Key Hacks
-====================================
-
-Documentation for sysrq.c
-
-What is the magic SysRq key?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-It is a 'magical' key combo you can hit which the kernel will respond to
-regardless of whatever else it is doing, unless it is completely locked up.
-
-How do I enable the magic SysRq key?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-You need to say "yes" to 'Magic SysRq key (CONFIG_MAGIC_SYSRQ)' when
-configuring the kernel. When running a kernel with SysRq compiled in,
-/proc/sys/kernel/sysrq controls the functions allowed to be invoked via
-the SysRq key. The default value in this file is set by the
-CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE config symbol, which itself defaults
-to 1. Here is the list of possible values in /proc/sys/kernel/sysrq:
-
- - 0 - disable sysrq completely
- - 1 - enable all functions of sysrq
- - >1 - bitmask of allowed sysrq functions (see below for detailed function
- description)::
-
- 2 = 0x2 - enable control of console logging level
- 4 = 0x4 - enable control of keyboard (SAK, unraw)
- 8 = 0x8 - enable debugging dumps of processes etc.
- 16 = 0x10 - enable sync command
- 32 = 0x20 - enable remount read-only
- 64 = 0x40 - enable signalling of processes (term, kill, oom-kill)
- 128 = 0x80 - allow reboot/poweroff
- 256 = 0x100 - allow nicing of all RT tasks
-
-You can set the value in the file by the following command::
-
- echo "number" >/proc/sys/kernel/sysrq
-
-The number may be written here either as decimal or as hexadecimal
-with the 0x prefix. CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE must always be
-written in hexadecimal.
-
-Note that the value of ``/proc/sys/kernel/sysrq`` influences only the invocation
-via a keyboard. Invocation of any operation via ``/proc/sysrq-trigger`` is
-always allowed (by a user with admin privileges).
-
-How do I use the magic SysRq key?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-On x86 - You press the key combo :kbd:`ALT-SysRq-<command key>`.
-
-.. note::
- Some
- keyboards may not have a key labeled 'SysRq'. The 'SysRq' key is
- also known as the 'Print Screen' key. Also some keyboards cannot
- handle so many keys being pressed at the same time, so you might
- have better luck with press :kbd:`Alt`, press :kbd:`SysRq`,
- release :kbd:`SysRq`, press :kbd:`<command key>`, release everything.
-
-On SPARC - You press :kbd:`ALT-STOP-<command key>`, I believe.
-
-On the serial console (PC style standard serial ports only)
- You send a ``BREAK``, then within 5 seconds a command key. Sending
- ``BREAK`` twice is interpreted as a normal BREAK.
-
-On PowerPC
- Press :kbd:`ALT - Print Screen` (or :kbd:`F13`) - :kbd:`<command key>`,
- :kbd:`Print Screen` (or :kbd:`F13`) - :kbd:`<command key>` may suffice.
-
-On other
- If you know of the key combos for other architectures, please
- let me know so I can add them to this section.
-
-On all
- write a character to /proc/sysrq-trigger. e.g.::
-
- echo t > /proc/sysrq-trigger
-
-What are the 'command' keys?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-=========== ===================================================================
-Command Function
-=========== ===================================================================
-``b`` Will immediately reboot the system without syncing or unmounting
- your disks.
-
-``c`` Will perform a system crash by a NULL pointer dereference.
- A crashdump will be taken if configured.
-
-``d`` Shows all locks that are held.
-
-``e`` Send a SIGTERM to all processes, except for init.
-
-``f`` Will call the oom killer to kill a memory hog process, but do not
- panic if nothing can be killed.
-
-``g`` Used by kgdb (kernel debugger)
-
-``h`` Will display help (actually any other key than those listed
- here will display help. but ``h`` is easy to remember :-)
-
-``i`` Send a SIGKILL to all processes, except for init.
-
-``j`` Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl.
-
-``k`` Secure Access Key (SAK) Kills all programs on the current virtual
- console. NOTE: See important comments below in SAK section.
-
-``l`` Shows a stack backtrace for all active CPUs.
-
-``m`` Will dump current memory info to your console.
-
-``n`` Used to make RT tasks nice-able
-
-``o`` Will shut your system off (if configured and supported).
-
-``p`` Will dump the current registers and flags to your console.
-
-``q`` Will dump per CPU lists of all armed hrtimers (but NOT regular
- timer_list timers) and detailed information about all
- clockevent devices.
-
-``r`` Turns off keyboard raw mode and sets it to XLATE.
-
-``s`` Will attempt to sync all mounted filesystems.
-
-``t`` Will dump a list of current tasks and their information to your
- console.
-
-``u`` Will attempt to remount all mounted filesystems read-only.
-
-``v`` Forcefully restores framebuffer console
-``v`` Causes ETM buffer dump [ARM-specific]
-
-``w`` Dumps tasks that are in uninterruptable (blocked) state.
-
-``x`` Used by xmon interface on ppc/powerpc platforms.
- Show global PMU Registers on sparc64.
- Dump all TLB entries on MIPS.
-
-``y`` Show global CPU Registers [SPARC-64 specific]
-
-``z`` Dump the ftrace buffer
-
-``0``-``9`` Sets the console log level, controlling which kernel messages
- will be printed to your console. (``0``, for example would make
- it so that only emergency messages like PANICs or OOPSes would
- make it to your console.)
-=========== ===================================================================
-
-Okay, so what can I use them for?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Well, unraw(r) is very handy when your X server or a svgalib program crashes.
-
-sak(k) (Secure Access Key) is useful when you want to be sure there is no
-trojan program running at console which could grab your password
-when you would try to login. It will kill all programs on given console,
-thus letting you make sure that the login prompt you see is actually
-the one from init, not some trojan program.
-
-.. important::
-
- In its true form it is not a true SAK like the one in a
- c2 compliant system, and it should not be mistaken as
- such.
-
-It seems others find it useful as (System Attention Key) which is
-useful when you want to exit a program that will not let you switch consoles.
-(For example, X or a svgalib program.)
-
-``reboot(b)`` is good when you're unable to shut down. But you should also
-``sync(s)`` and ``umount(u)`` first.
-
-``crash(c)`` can be used to manually trigger a crashdump when the system is hung.
-Note that this just triggers a crash if there is no dump mechanism available.
-
-``sync(s)`` is great when your system is locked up, it allows you to sync your
-disks and will certainly lessen the chance of data loss and fscking. Note
-that the sync hasn't taken place until you see the "OK" and "Done" appear
-on the screen. (If the kernel is really in strife, you may not ever get the
-OK or Done message...)
-
-``umount(u)`` is basically useful in the same ways as ``sync(s)``. I generally
-``sync(s)``, ``umount(u)``, then ``reboot(b)`` when my system locks. It's saved
-me many a fsck. Again, the unmount (remount read-only) hasn't taken place until
-you see the "OK" and "Done" message appear on the screen.
-
-The loglevels ``0``-``9`` are useful when your console is being flooded with
-kernel messages you do not want to see. Selecting ``0`` will prevent all but
-the most urgent kernel messages from reaching your console. (They will
-still be logged if syslogd/klogd are alive, though.)
-
-``term(e)`` and ``kill(i)`` are useful if you have some sort of runaway process
-you are unable to kill any other way, especially if it's spawning other
-processes.
-
-"just thaw ``it(j)``" is useful if your system becomes unresponsive due to a
-frozen (probably root) filesystem via the FIFREEZE ioctl.
-
-Sometimes SysRq seems to get 'stuck' after using it, what can I do?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-That happens to me, also. I've found that tapping shift, alt, and control
-on both sides of the keyboard, and hitting an invalid sysrq sequence again
-will fix the problem. (i.e., something like :kbd:`alt-sysrq-z`). Switching to
-another virtual console (:kbd:`ALT+Fn`) and then back again should also help.
-
-I hit SysRq, but nothing seems to happen, what's wrong?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-There are some keyboards that produce a different keycode for SysRq than the
-pre-defined value of 99 (see ``KEY_SYSRQ`` in ``include/linux/input.h``), or
-which don't have a SysRq key at all. In these cases, run ``showkey -s`` to find
-an appropriate scancode sequence, and use ``setkeycodes <sequence> 99`` to map
-this sequence to the usual SysRq code (e.g., ``setkeycodes e05b 99``). It's
-probably best to put this command in a boot script. Oh, and by the way, you
-exit ``showkey`` by not typing anything for ten seconds.
-
-I want to add SysRQ key events to a module, how does it work?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-In order to register a basic function with the table, you must first include
-the header ``include/linux/sysrq.h``, this will define everything else you need.
-Next, you must create a ``sysrq_key_op`` struct, and populate it with A) the key
-handler function you will use, B) a help_msg string, that will print when SysRQ
-prints help, and C) an action_msg string, that will print right before your
-handler is called. Your handler must conform to the prototype in 'sysrq.h'.
-
-After the ``sysrq_key_op`` is created, you can call the kernel function
-``register_sysrq_key(int key, struct sysrq_key_op *op_p);`` this will
-register the operation pointed to by ``op_p`` at table key 'key',
-if that slot in the table is blank. At module unload time, you must call
-the function ``unregister_sysrq_key(int key, struct sysrq_key_op *op_p)``, which
-will remove the key op pointed to by 'op_p' from the key 'key', if and only if
-it is currently registered in that slot. This is in case the slot has been
-overwritten since you registered it.
-
-The Magic SysRQ system works by registering key operations against a key op
-lookup table, which is defined in 'drivers/tty/sysrq.c'. This key table has
-a number of operations registered into it at compile time, but is mutable,
-and 2 functions are exported for interface to it::
-
- register_sysrq_key and unregister_sysrq_key.
-
-Of course, never ever leave an invalid pointer in the table. I.e., when
-your module that called register_sysrq_key() exits, it must call
-unregister_sysrq_key() to clean up the sysrq key table entry that it used.
-Null pointers in the table are always safe. :)
-
-If for some reason you feel the need to call the handle_sysrq function from
-within a function called by handle_sysrq, you must be aware that you are in
-a lock (you are also in an interrupt handler, which means don't sleep!), so
-you must call ``__handle_sysrq_nolock`` instead.
-
-When I hit a SysRq key combination only the header appears on the console?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Sysrq output is subject to the same console loglevel control as all
-other console output. This means that if the kernel was booted 'quiet'
-as is common on distro kernels the output may not appear on the actual
-console, even though it will appear in the dmesg buffer, and be accessible
-via the dmesg command and to the consumers of ``/proc/kmsg``. As a specific
-exception the header line from the sysrq command is passed to all console
-consumers as if the current loglevel was maximum. If only the header
-is emitted it is almost certain that the kernel loglevel is too low.
-Should you require the output on the console channel then you will need
-to temporarily up the console loglevel using :kbd:`alt-sysrq-8` or::
-
- echo 8 > /proc/sysrq-trigger
-
-Remember to return the loglevel to normal after triggering the sysrq
-command you are interested in.
-
-I have more questions, who can I ask?
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Just ask them on the linux-kernel mailing list:
- linux-kernel@vger.kernel.org
-
-Credits
-~~~~~~~
-
-Written by Mydraal <vulpyne@vulpyne.net>
-Updated by Adam Sulmicki <adam@cfar.umd.edu>
-Updated by Jeremy M. Dolan <jmd@turbogeek.org> 2001/01/28 10:15:59
-Added to by Crutcher Dunnavant <crutcher+kernel@datastacks.com>
+++ /dev/null
-Unicode support
-===============
-
- Last update: 2005-01-17, version 1.4
-
-This file is maintained by H. Peter Anvin <unicode@lanana.org> as part
-of the Linux Assigned Names And Numbers Authority (LANANA) project.
-The current version can be found at:
-
- http://www.lanana.org/docs/unicode/unicode.txt
-
-Introdution
------------
-
-The Linux kernel code has been rewritten to use Unicode to map
-characters to fonts. By downloading a single Unicode-to-font table,
-both the eight-bit character sets and UTF-8 mode are changed to use
-the font as indicated.
-
-This changes the semantics of the eight-bit character tables subtly.
-The four character tables are now:
-
-=============== =============================== ================
-Map symbol Map name Escape code (G0)
-=============== =============================== ================
-LAT1_MAP Latin-1 (ISO 8859-1) ESC ( B
-GRAF_MAP DEC VT100 pseudographics ESC ( 0
-IBMPC_MAP IBM code page 437 ESC ( U
-USER_MAP User defined ESC ( K
-=============== =============================== ================
-
-In particular, ESC ( U is no longer "straight to font", since the font
-might be completely different than the IBM character set. This
-permits for example the use of block graphics even with a Latin-1 font
-loaded.
-
-Note that although these codes are similar to ISO 2022, neither the
-codes nor their uses match ISO 2022; Linux has two 8-bit codes (G0 and
-G1), whereas ISO 2022 has four 7-bit codes (G0-G3).
-
-In accordance with the Unicode standard/ISO 10646 the range U+F000 to
-U+F8FF has been reserved for OS-wide allocation (the Unicode Standard
-refers to this as a "Corporate Zone", since this is inaccurate for
-Linux we call it the "Linux Zone"). U+F000 was picked as the starting
-point since it lets the direct-mapping area start on a large power of
-two (in case 1024- or 2048-character fonts ever become necessary).
-This leaves U+E000 to U+EFFF as End User Zone.
-
-[v1.2]: The Unicodes range from U+F000 and up to U+F7FF have been
-hard-coded to map directly to the loaded font, bypassing the
-translation table. The user-defined map now defaults to U+F000 to
-U+F0FF, emulating the previous behaviour. In practice, this range
-might be shorter; for example, vgacon can only handle 256-character
-(U+F000..U+F0FF) or 512-character (U+F000..U+F1FF) fonts.
-
-
-Actual characters assigned in the Linux Zone
---------------------------------------------
-
-In addition, the following characters not present in Unicode 1.1.4
-have been defined; these are used by the DEC VT graphics map. [v1.2]
-THIS USE IS OBSOLETE AND SHOULD NO LONGER BE USED; PLEASE SEE BELOW.
-
-====== ======================================
-U+F800 DEC VT GRAPHICS HORIZONTAL LINE SCAN 1
-U+F801 DEC VT GRAPHICS HORIZONTAL LINE SCAN 3
-U+F803 DEC VT GRAPHICS HORIZONTAL LINE SCAN 7
-U+F804 DEC VT GRAPHICS HORIZONTAL LINE SCAN 9
-====== ======================================
-
-The DEC VT220 uses a 6x10 character matrix, and these characters form
-a smooth progression in the DEC VT graphics character set. I have
-omitted the scan 5 line, since it is also used as a block-graphics
-character, and hence has been coded as U+2500 FORMS LIGHT HORIZONTAL.
-
-[v1.3]: These characters have been officially added to Unicode 3.2.0;
-they are added at U+23BA, U+23BB, U+23BC, U+23BD. Linux now uses the
-new values.
-
-[v1.2]: The following characters have been added to represent common
-keyboard symbols that are unlikely to ever be added to Unicode proper
-since they are horribly vendor-specific. This, of course, is an
-excellent example of horrible design.
-
-====== ======================================
-U+F810 KEYBOARD SYMBOL FLYING FLAG
-U+F811 KEYBOARD SYMBOL PULLDOWN MENU
-U+F812 KEYBOARD SYMBOL OPEN APPLE
-U+F813 KEYBOARD SYMBOL SOLID APPLE
-====== ======================================
-
-Klingon language support
-------------------------
-
-In 1996, Linux was the first operating system in the world to add
-support for the artificial language Klingon, created by Marc Okrand
-for the "Star Trek" television series. This encoding was later
-adopted by the ConScript Unicode Registry and proposed (but ultimately
-rejected) for inclusion in Unicode Plane 1. Thus, it remains as a
-Linux/CSUR private assignment in the Linux Zone.
-
-This encoding has been endorsed by the Klingon Language Institute.
-For more information, contact them at:
-
- http://www.kli.org/
-
-Since the characters in the beginning of the Linux CZ have been more
-of the dingbats/symbols/forms type and this is a language, I have
-located it at the end, on a 16-cell boundary in keeping with standard
-Unicode practice.
-
-.. note::
-
- This range is now officially managed by the ConScript Unicode
- Registry. The normative reference is at:
-
- http://www.evertype.com/standards/csur/klingon.html
-
-Klingon has an alphabet of 26 characters, a positional numeric writing
-system with 10 digits, and is written left-to-right, top-to-bottom.
-
-Several glyph forms for the Klingon alphabet have been proposed.
-However, since the set of symbols appear to be consistent throughout,
-with only the actual shapes being different, in keeping with standard
-Unicode practice these differences are considered font variants.
-
-====== =======================================================
-U+F8D0 KLINGON LETTER A
-U+F8D1 KLINGON LETTER B
-U+F8D2 KLINGON LETTER CH
-U+F8D3 KLINGON LETTER D
-U+F8D4 KLINGON LETTER E
-U+F8D5 KLINGON LETTER GH
-U+F8D6 KLINGON LETTER H
-U+F8D7 KLINGON LETTER I
-U+F8D8 KLINGON LETTER J
-U+F8D9 KLINGON LETTER L
-U+F8DA KLINGON LETTER M
-U+F8DB KLINGON LETTER N
-U+F8DC KLINGON LETTER NG
-U+F8DD KLINGON LETTER O
-U+F8DE KLINGON LETTER P
-U+F8DF KLINGON LETTER Q
- - Written <q> in standard Okrand Latin transliteration
-U+F8E0 KLINGON LETTER QH
- - Written <Q> in standard Okrand Latin transliteration
-U+F8E1 KLINGON LETTER R
-U+F8E2 KLINGON LETTER S
-U+F8E3 KLINGON LETTER T
-U+F8E4 KLINGON LETTER TLH
-U+F8E5 KLINGON LETTER U
-U+F8E6 KLINGON LETTER V
-U+F8E7 KLINGON LETTER W
-U+F8E8 KLINGON LETTER Y
-U+F8E9 KLINGON LETTER GLOTTAL STOP
-
-U+F8F0 KLINGON DIGIT ZERO
-U+F8F1 KLINGON DIGIT ONE
-U+F8F2 KLINGON DIGIT TWO
-U+F8F3 KLINGON DIGIT THREE
-U+F8F4 KLINGON DIGIT FOUR
-U+F8F5 KLINGON DIGIT FIVE
-U+F8F6 KLINGON DIGIT SIX
-U+F8F7 KLINGON DIGIT SEVEN
-U+F8F8 KLINGON DIGIT EIGHT
-U+F8F9 KLINGON DIGIT NINE
-
-U+F8FD KLINGON COMMA
-U+F8FE KLINGON FULL STOP
-U+F8FF KLINGON SYMBOL FOR EMPIRE
-====== =======================================================
-
-Other Fictional and Artificial Scripts
---------------------------------------
-
-Since the assignment of the Klingon Linux Unicode block, a registry of
-fictional and artificial scripts has been established by John Cowan
-<jcowan@reutershealth.com> and Michael Everson <everson@evertype.com>.
-The ConScript Unicode Registry is accessible at:
-
- http://www.evertype.com/standards/csur/
-
-The ranges used fall at the low end of the End User Zone and can hence
-not be normatively assigned, but it is recommended that people who
-wish to encode fictional scripts use these codes, in the interest of
-interoperability. For Klingon, CSUR has adopted the Linux encoding.
-The CSUR people are driving adding Tengwar and Cirth into Unicode
-Plane 1; the addition of Klingon to Unicode Plane 1 has been rejected
-and so the above encoding remains official.
+++ /dev/null
-Linux kernel release 4.x <http://kernel.org/>
-=============================================
-
-These are the release notes for Linux version 4. Read them carefully,
-as they tell you what this is all about, explain how to install the
-kernel, and what to do if something goes wrong.
-
-What is Linux?
---------------
-
- Linux is a clone of the operating system Unix, written from scratch by
- Linus Torvalds with assistance from a loosely-knit team of hackers across
- the Net. It aims towards POSIX and Single UNIX Specification compliance.
-
- It has all the features you would expect in a modern fully-fledged Unix,
- including true multitasking, virtual memory, shared libraries, demand
- loading, shared copy-on-write executables, proper memory management,
- and multistack networking including IPv4 and IPv6.
-
- It is distributed under the GNU General Public License - see the
- accompanying COPYING file for more details.
-
-On what hardware does it run?
------------------------------
-
- Although originally developed first for 32-bit x86-based PCs (386 or higher),
- today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
- UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
- IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
- Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures.
-
- Linux is easily portable to most general-purpose 32- or 64-bit architectures
- as long as they have a paged memory management unit (PMMU) and a port of the
- GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
- also been ported to a number of architectures without a PMMU, although
- functionality is then obviously somewhat limited.
- Linux has also been ported to itself. You can now run the kernel as a
- userspace application - this is called UserMode Linux (UML).
-
-Documentation
--------------
-
- - There is a lot of documentation available both in electronic form on
- the Internet and in books, both Linux-specific and pertaining to
- general UNIX questions. I'd recommend looking into the documentation
- subdirectories on any Linux FTP site for the LDP (Linux Documentation
- Project) books. This README is not meant to be documentation on the
- system: there are much better sources available.
-
- - There are various README files in the Documentation/ subdirectory:
- these typically contain kernel-specific installation notes for some
- drivers for example. See Documentation/00-INDEX for a list of what
- is contained in each file. Please read the Changes file, as it
- contains information about the problems, which may result by upgrading
- your kernel.
-
- - The Documentation/DocBook/ subdirectory contains several guides for
- kernel developers and users. These guides can be rendered in a
- number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
- After installation, ``make psdocs``, ``make pdfdocs``, ``make htmldocs``,
- or ``make mandocs`` will render the documentation in the requested format.
-
-Installing the kernel source
-----------------------------
-
- - If you install the full sources, put the kernel tarball in a
- directory where you have permissions (e.g. your home directory) and
- unpack it::
-
- xz -cd linux-4.X.tar.xz | tar xvf -
-
- Replace "X" with the version number of the latest kernel.
-
- Do NOT use the /usr/src/linux area! This area has a (usually
- incomplete) set of kernel headers that are used by the library header
- files. They should match the library, and not get messed up by
- whatever the kernel-du-jour happens to be.
-
- - You can also upgrade between 4.x releases by patching. Patches are
- distributed in the xz format. To install by patching, get all the
- newer patch files, enter the top level directory of the kernel source
- (linux-4.X) and execute::
-
- xz -cd ../patch-4.x.xz | patch -p1
-
- Replace "x" for all versions bigger than the version "X" of your current
- source tree, **in_order**, and you should be ok. You may want to remove
- the backup files (some-file-name~ or some-file-name.orig), and make sure
- that there are no failed patches (some-file-name# or some-file-name.rej).
- If there are, either you or I have made a mistake.
-
- Unlike patches for the 4.x kernels, patches for the 4.x.y kernels
- (also known as the -stable kernels) are not incremental but instead apply
- directly to the base 4.x kernel. For example, if your base kernel is 4.0
- and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1
- and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and
- want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is,
- patch -R) **before** applying the 4.0.3 patch. You can read more on this in
- :ref:`Documentation/applying-patches.txt <applying_patches>`.
-
- Alternatively, the script patch-kernel can be used to automate this
- process. It determines the current kernel version and applies any
- patches found::
-
- linux/scripts/patch-kernel linux
-
- The first argument in the command above is the location of the
- kernel source. Patches are applied from the current directory, but
- an alternative directory can be specified as the second argument.
-
- - Make sure you have no stale .o files and dependencies lying around::
-
- cd linux
- make mrproper
-
- You should now have the sources correctly installed.
-
-Software requirements
----------------------
-
- Compiling and running the 4.x kernels requires up-to-date
- versions of various software packages. Consult
- :ref:`Documentation/Changes <changes>` for the minimum version numbers
- required and how to get updates for these packages. Beware that using
- excessively old versions of these packages can cause indirect
- errors that are very difficult to track down, so don't assume that
- you can just update packages when obvious problems arise during
- build or operation.
-
-Build directory for the kernel
-------------------------------
-
- When compiling the kernel, all output files will per default be
- stored together with the kernel source code.
- Using the option ``make O=output/dir`` allows you to specify an alternate
- place for the output files (including .config).
- Example::
-
- kernel source code: /usr/src/linux-4.X
- build directory: /home/name/build/kernel
-
- To configure and build the kernel, use::
-
- cd /usr/src/linux-4.X
- make O=/home/name/build/kernel menuconfig
- make O=/home/name/build/kernel
- sudo make O=/home/name/build/kernel modules_install install
-
- Please note: If the ``O=output/dir`` option is used, then it must be
- used for all invocations of make.
-
-Configuring the kernel
-----------------------
-
- Do not skip this step even if you are only upgrading one minor
- version. New configuration options are added in each release, and
- odd problems will turn up if the configuration files are not set up
- as expected. If you want to carry your existing configuration to a
- new version with minimal work, use ``make oldconfig``, which will
- only ask you for the answers to new questions.
-
- - Alternative configuration commands are::
-
- "make config" Plain text interface.
-
- "make menuconfig" Text based color menus, radiolists & dialogs.
-
- "make nconfig" Enhanced text based color menus.
-
- "make xconfig" Qt based configuration tool.
-
- "make gconfig" GTK+ based configuration tool.
-
- "make oldconfig" Default all questions based on the contents of
- your existing ./.config file and asking about
- new config symbols.
-
- "make silentoldconfig"
- Like above, but avoids cluttering the screen
- with questions already answered.
- Additionally updates the dependencies.
-
- "make olddefconfig"
- Like above, but sets new symbols to their default
- values without prompting.
-
- "make defconfig" Create a ./.config file by using the default
- symbol values from either arch/$ARCH/defconfig
- or arch/$ARCH/configs/${PLATFORM}_defconfig,
- depending on the architecture.
-
- "make ${PLATFORM}_defconfig"
- Create a ./.config file by using the default
- symbol values from
- arch/$ARCH/configs/${PLATFORM}_defconfig.
- Use "make help" to get a list of all available
- platforms of your architecture.
-
- "make allyesconfig"
- Create a ./.config file by setting symbol
- values to 'y' as much as possible.
-
- "make allmodconfig"
- Create a ./.config file by setting symbol
- values to 'm' as much as possible.
-
- "make allnoconfig" Create a ./.config file by setting symbol
- values to 'n' as much as possible.
-
- "make randconfig" Create a ./.config file by setting symbol
- values to random values.
-
- "make localmodconfig" Create a config based on current config and
- loaded modules (lsmod). Disables any module
- option that is not needed for the loaded modules.
-
- To create a localmodconfig for another machine,
- store the lsmod of that machine into a file
- and pass it in as a LSMOD parameter.
-
- target$ lsmod > /tmp/mylsmod
- target$ scp /tmp/mylsmod host:/tmp
-
- host$ make LSMOD=/tmp/mylsmod localmodconfig
-
- The above also works when cross compiling.
-
- "make localyesconfig" Similar to localmodconfig, except it will convert
- all module options to built in (=y) options.
-
- You can find more information on using the Linux kernel config tools
- in Documentation/kbuild/kconfig.txt.
-
- - NOTES on ``make config``:
-
- - Having unnecessary drivers will make the kernel bigger, and can
- under some circumstances lead to problems: probing for a
- nonexistent controller card may confuse your other controllers
-
- - A kernel with math-emulation compiled in will still use the
- coprocessor if one is present: the math emulation will just
- never get used in that case. The kernel will be slightly larger,
- but will work on different machines regardless of whether they
- have a math coprocessor or not.
-
- - The "kernel hacking" configuration details usually result in a
- bigger or slower kernel (or both), and can even make the kernel
- less stable by configuring some routines to actively try to
- break bad code to find kernel problems (kmalloc()). Thus you
- should probably answer 'n' to the questions for "development",
- "experimental", or "debugging" features.
-
-Compiling the kernel
---------------------
-
- - Make sure you have at least gcc 3.2 available.
- For more information, refer to :ref:`Documentation/Changes <changes>`.
-
- Please note that you can still run a.out user programs with this kernel.
-
- - Do a ``make`` to create a compressed kernel image. It is also
- possible to do ``make install`` if you have lilo installed to suit the
- kernel makefiles, but you may want to check your particular lilo setup first.
-
- To do the actual install, you have to be root, but none of the normal
- build should require that. Don't take the name of root in vain.
-
- - If you configured any of the parts of the kernel as ``modules``, you
- will also have to do ``make modules_install``.
-
- - Verbose kernel compile/build output:
-
- Normally, the kernel build system runs in a fairly quiet mode (but not
- totally silent). However, sometimes you or other kernel developers need
- to see compile, link, or other commands exactly as they are executed.
- For this, use "verbose" build mode. This is done by passing
- ``V=1`` to the ``make`` command, e.g.::
-
- make V=1 all
-
- To have the build system also tell the reason for the rebuild of each
- target, use ``V=2``. The default is ``V=0``.
-
- - Keep a backup kernel handy in case something goes wrong. This is
- especially true for the development releases, since each new release
- contains new code which has not been debugged. Make sure you keep a
- backup of the modules corresponding to that kernel, as well. If you
- are installing a new kernel with the same version number as your
- working kernel, make a backup of your modules directory before you
- do a ``make modules_install``.
-
- Alternatively, before compiling, use the kernel config option
- "LOCALVERSION" to append a unique suffix to the regular kernel version.
- LOCALVERSION can be set in the "General Setup" menu.
-
- - In order to boot your new kernel, you'll need to copy the kernel
- image (e.g. .../linux/arch/x86/boot/bzImage after compilation)
- to the place where your regular bootable kernel is found.
-
- - Booting a kernel directly from a floppy without the assistance of a
- bootloader such as LILO, is no longer supported.
-
- If you boot Linux from the hard drive, chances are you use LILO, which
- uses the kernel image as specified in the file /etc/lilo.conf. The
- kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
- /boot/bzImage. To use the new kernel, save a copy of the old image
- and copy the new image over the old one. Then, you MUST RERUN LILO
- to update the loading map! If you don't, you won't be able to boot
- the new kernel image.
-
- Reinstalling LILO is usually a matter of running /sbin/lilo.
- You may wish to edit /etc/lilo.conf to specify an entry for your
- old kernel image (say, /vmlinux.old) in case the new one does not
- work. See the LILO docs for more information.
-
- After reinstalling LILO, you should be all set. Shutdown the system,
- reboot, and enjoy!
-
- If you ever need to change the default root device, video mode,
- ramdisk size, etc. in the kernel image, use the ``rdev`` program (or
- alternatively the LILO boot options when appropriate). No need to
- recompile the kernel to change these parameters.
-
- - Reboot with the new kernel and enjoy.
-
-If something goes wrong
------------------------
-
- - If you have problems that seem to be due to kernel bugs, please check
- the file MAINTAINERS to see if there is a particular person associated
- with the part of the kernel that you are having trouble with. If there
- isn't anyone listed there, then the second best thing is to mail
- them to me (torvalds@linux-foundation.org), and possibly to any other
- relevant mailing-list or to the newsgroup.
-
- - In all bug-reports, *please* tell what kernel you are talking about,
- how to duplicate the problem, and what your setup is (use your common
- sense). If the problem is new, tell me so, and if the problem is
- old, please try to tell me when you first noticed it.
-
- - If the bug results in a message like::
-
- unable to handle kernel paging request at address C0000010
- Oops: 0002
- EIP: 0010:XXXXXXXX
- eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
- esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
- ds: xxxx es: xxxx fs: xxxx gs: xxxx
- Pid: xx, process nr: xx
- xx xx xx xx xx xx xx xx xx xx
-
- or similar kernel debugging information on your screen or in your
- system log, please duplicate it *exactly*. The dump may look
- incomprehensible to you, but it does contain information that may
- help debugging the problem. The text above the dump is also
- important: it tells something about why the kernel dumped code (in
- the above example, it's due to a bad kernel pointer). More information
- on making sense of the dump is in Documentation/oops-tracing.txt
-
- - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
- as is, otherwise you will have to use the ``ksymoops`` program to make
- sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
- This utility can be downloaded from
- ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
- Alternatively, you can do the dump lookup by hand:
-
- - In debugging dumps like the above, it helps enormously if you can
- look up what the EIP value means. The hex value as such doesn't help
- me or anybody else very much: it will depend on your particular
- kernel setup. What you should do is take the hex value from the EIP
- line (ignore the ``0010:``), and look it up in the kernel namelist to
- see which kernel function contains the offending address.
-
- To find out the kernel function name, you'll need to find the system
- binary associated with the kernel that exhibited the symptom. This is
- the file 'linux/vmlinux'. To extract the namelist and match it against
- the EIP from the kernel crash, do::
-
- nm vmlinux | sort | less
-
- This will give you a list of kernel addresses sorted in ascending
- order, from which it is simple to find the function that contains the
- offending address. Note that the address given by the kernel
- debugging messages will not necessarily match exactly with the
- function addresses (in fact, that is very unlikely), so you can't
- just 'grep' the list: the list will, however, give you the starting
- point of each kernel function, so by looking for the function that
- has a starting address lower than the one you are searching for but
- is followed by a function with a higher address you will find the one
- you want. In fact, it may be a good idea to include a bit of
- "context" in your problem report, giving a few lines around the
- interesting one.
-
- If you for some reason cannot do the above (you have a pre-compiled
- kernel image or similar), telling me as much about your setup as
- possible will help. Please read the :ref:`REPORTING-BUGS <reportingbugs>`
- document for details.
-
- - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
- cannot change values or set break points.) To do this, first compile the
- kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make
- clean``. You'll also need to enable CONFIG_PROC_FS (via ``make config``).
-
- After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``.
- You can now use all the usual gdb commands. The command to look up the
- point where your system crashed is ``l *0xXXXXXXXX``. (Replace the XXXes
- with the EIP value.)
-
- gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly)
- disregards the starting offset for which the kernel is compiled.
-
+++ /dev/null
-.. _reportingbugs:
-
-Reporting bugs
-++++++++++++++
-
-Background
-==========
-
-The upstream Linux kernel maintainers only fix bugs for specific kernel
-versions. Those versions include the current "release candidate" (or -rc)
-kernel, any "stable" kernel versions, and any "long term" kernels.
-
-Please see https://www.kernel.org/ for a list of supported kernels. Any
-kernel marked with [EOL] is "end of life" and will not have any fixes
-backported to it.
-
-If you've found a bug on a kernel version that isn't listed on kernel.org,
-contact your Linux distribution or embedded vendor for support.
-Alternatively, you can attempt to run one of the supported stable or -rc
-kernels, and see if you can reproduce the bug on that. It's preferable
-to reproduce the bug on the latest -rc kernel.
-
-
-How to report Linux kernel bugs
-===============================
-
-
-Identify the problematic subsystem
-----------------------------------
-
-Identifying which part of the Linux kernel might be causing your issue
-increases your chances of getting your bug fixed. Simply posting to the
-generic linux-kernel mailing list (LKML) may cause your bug report to be
-lost in the noise of a mailing list that gets 1000+ emails a day.
-
-Instead, try to figure out which kernel subsystem is causing the issue,
-and email that subsystem's maintainer and mailing list. If the subsystem
-maintainer doesn't answer, then expand your scope to mailing lists like
-LKML.
-
-
-Identify who to notify
-----------------------
-
-Once you know the subsystem that is causing the issue, you should send a
-bug report. Some maintainers prefer bugs to be reported via bugzilla
-(https://bugzilla.kernel.org), while others prefer that bugs be reported
-via the subsystem mailing list.
-
-To find out where to send an emailed bug report, find your subsystem or
-device driver in the MAINTAINERS file. Search in the file for relevant
-entries, and send your bug report to the person(s) listed in the "M:"
-lines, making sure to Cc the mailing list(s) in the "L:" lines. When the
-maintainer replies to you, make sure to 'Reply-all' in order to keep the
-public mailing list(s) in the email thread.
-
-If you know which driver is causing issues, you can pass one of the driver
-files to the get_maintainer.pl script::
-
- perl scripts/get_maintainer.pl -f <filename>
-
-If it is a security bug, please copy the Security Contact listed in the
-MAINTAINERS file. They can help coordinate bugfix and disclosure. See
-:ref:`Documentation/SecurityBugs <securitybugs>` for more information.
-
-If you can't figure out which subsystem caused the issue, you should file
-a bug in kernel.org bugzilla and send email to
-linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more
-information on the linux-kernel mailing list see
-http://www.tux.org/lkml/).
-
-
-Tips for reporting bugs
------------------------
-
-If you haven't reported a bug before, please read:
-
- http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
-
- http://www.catb.org/esr/faqs/smart-questions.html
-
-It's REALLY important to report bugs that seem unrelated as separate email
-threads or separate bugzilla entries. If you report several unrelated
-bugs at once, it's difficult for maintainers to tease apart the relevant
-data.
-
-
-Gather information
-------------------
-
-The most important information in a bug report is how to reproduce the
-bug. This includes system information, and (most importantly)
-step-by-step instructions for how a user can trigger the bug.
-
-If the failure includes an "OOPS:", take a picture of the screen, capture
-a netconsole trace, or type the message from your screen into the bug
-report. Please read "Documentation/oops-tracing.txt" before posting your
-bug report. This explains what you should do with the "Oops" information
-to make it useful to the recipient.
-
-This is a suggested format for a bug report sent via email or bugzilla.
-Having a standardized bug report form makes it easier for you not to
-overlook things, and easier for the developers to find the pieces of
-information they're really interested in. If some information is not
-relevant to your bug, feel free to exclude it.
-
-First run the ver_linux script included as scripts/ver_linux, which
-reports the version of some important subsystems. Run this script with
-the command ``sh scripts/ver_linux``.
-
-Use that information to fill in all fields of the bug report form, and
-post it to the mailing list with a subject of "PROBLEM: <one line
-summary from [1.]>" for easy identification by the developers::
-
- [1.] One line summary of the problem:
- [2.] Full description of the problem/report:
- [3.] Keywords (i.e., modules, networking, kernel):
- [4.] Kernel information
- [4.1.] Kernel version (from /proc/version):
- [4.2.] Kernel .config file:
- [5.] Most recent kernel version which did not have the bug:
- [6.] Output of Oops.. message (if applicable) with symbolic information
- resolved (see Documentation/oops-tracing.txt)
- [7.] A small shell script or example program which triggers the
- problem (if possible)
- [8.] Environment
- [8.1.] Software (add the output of the ver_linux script here)
- [8.2.] Processor information (from /proc/cpuinfo):
- [8.3.] Module information (from /proc/modules):
- [8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
- [8.5.] PCI information ('lspci -vvv' as root)
- [8.6.] SCSI information (from /proc/scsi/scsi)
- [8.7.] Other information that might be relevant to the problem
- (please look in /proc and include all information that you
- think to be relevant):
- [X.] Other notes, patches, fixes, workarounds:
-
-
-Follow up
-=========
-
-Expectations for bug reporters
-------------------------------
-
-Linux kernel maintainers expect bug reporters to be able to follow up on
-bug reports. That may include running new tests, applying patches,
-recompiling your kernel, and/or re-triggering your bug. The most
-frustrating thing for maintainers is for someone to report a bug, and then
-never follow up on a request to try out a fix.
-
-That said, it's still useful for a kernel maintainer to know a bug exists
-on a supported kernel, even if you can't follow up with retests. Follow
-up reports, such as replying to the email thread with "I tried the latest
-kernel and I can't reproduce my bug anymore" are also helpful, because
-maintainers have to assume silence means things are still broken.
-
-Expectations for kernel maintainers
------------------------------------
-
-Linux kernel maintainers are busy, overworked human beings. Some times
-they may not be able to address your bug in a day, a week, or two weeks.
-If they don't answer your email, they may be on vacation, or at a Linux
-conference. Check the conference schedule at https://LWN.net for more info:
-
- https://lwn.net/Calendar/
-
-In general, kernel maintainers take 1 to 5 business days to respond to
-bugs. The majority of kernel maintainers are employed to work on the
-kernel, and they may not work on the weekends. Maintainers are scattered
-around the world, and they may not work in your time zone. Unless you
-have a high priority bug, please wait at least a week after the first bug
-report before sending the maintainer a reminder email.
-
-The exceptions to this rule are regressions, kernel crashes, security holes,
-or userspace breakage caused by new kernel behavior. Those bugs should be
-addressed by the maintainers ASAP. If you suspect a maintainer is not
-responding to these types of bugs in a timely manner (especially during a
-merge window), escalate the bug to LKML and Linus Torvalds.
-
-Thank you!
-
-[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]
projects / linux-2.6-block.git / commitdiff