[PATCH] percpu_counter_sum()
[linux-block.git] / Documentation / kernel-parameters.txt
CommitLineData
1da177e4
LT
1February 2003 Kernel Parameters v2.5.59
2 ~~~~~~~~~~~~~~~~~
3
4The following is a consolidated list of the kernel parameters as implemented
5(mostly) by the __setup() macro and sorted into English Dictionary order
6(defined as ignoring all punctuation and sorting digits before letters in a
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are specified on the kernel command line with the module name plus
16'.' plus parameter name, with '=' and value if appropriate, such as:
17
18 usbcore.blinkenlights=1
19
a9913044 20The text in square brackets at the beginning of the description states the
1da177e4
LT
21restrictions on the kernel for the said kernel parameter to be valid. The
22restrictions referred to are that the relevant option is valid if:
23
24 ACPI ACPI support is enabled.
25 ALSA ALSA sound support is enabled.
26 APIC APIC support is enabled.
27 APM Advanced Power Management support is enabled.
28 AX25 Appropriate AX.25 support is enabled.
29 CD Appropriate CD support is enabled.
a9913044
RD
30 DEVFS devfs support is enabled.
31 DRM Direct Rendering Management support is enabled.
1da177e4
LT
32 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
33 EFI EFI Partitioning (GPT) is enabled
34 EIDE EIDE/ATAPI support is enabled.
35 FB The frame buffer device is enabled.
36 HW Appropriate hardware is enabled.
37 IA-32 IA-32 aka i386 architecture is enabled.
38 IA-64 IA-64 architecture is enabled.
39 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 40 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
1da177e4
LT
41 ISAPNP ISA PnP code is enabled.
42 ISDN Appropriate ISDN support is enabled.
43 JOY Appropriate joystick support is enabled.
44 LP Printer support is enabled.
45 LOOP Loopback device support is enabled.
46 M68k M68k architecture is enabled.
47 These options have more detailed description inside of
48 Documentation/m68k/kernel-options.txt.
49 MCA MCA bus support is enabled.
50 MDA MDA console support is enabled.
51 MOUSE Appropriate mouse support is enabled.
52 MTD MTD support is enabled.
53 NET Appropriate network support is enabled.
54 NUMA NUMA support is enabled.
55 NFS Appropriate NFS support is enabled.
56 OSS OSS sound support is enabled.
57 PARIDE The ParIDE subsystem is enabled.
58 PARISC The PA-RISC architecture is enabled.
59 PCI PCI bus support is enabled.
60 PCMCIA The PCMCIA subsystem is enabled.
61 PNP Plug & Play support is enabled.
62 PPC PowerPC architecture is enabled.
63 PPT Parallel port support is enabled.
64 PS2 Appropriate PS/2 support is enabled.
65 RAM RAM disk support is enabled.
66 S390 S390 architecture is enabled.
67 SCSI Appropriate SCSI support is enabled.
68 A lot of drivers has their options described inside of
69 Documentation/scsi/.
70 SELINUX SELinux support is enabled.
71 SERIAL Serial support is enabled.
72 SMP The kernel is an SMP kernel.
73 SPARC Sparc architecture is enabled.
a9913044 74 SWSUSP Software suspend is enabled.
1da177e4
LT
75 TS Appropriate touchscreen support is enabled.
76 USB USB support is enabled.
77 USBHID USB Human Interface Device support is enabled.
78 V4L Video For Linux support is enabled.
79 VGA The VGA console has been enabled.
80 VT Virtual terminal support is enabled.
81 WDT Watchdog support is enabled.
82 XT IBM PC/XT MFM hard disk support is enabled.
83 X86-64 X86-64 architecture is enabled.
84 More X86-64 boot options can be found in
85 Documentation/x86_64/boot-options.txt .
86
87In addition, the following text indicates that the option:
88
89 BUGS= Relates to possible processor bugs on the said processor.
90 KNL Is a kernel start-up parameter.
91 BOOT Is a boot loader parameter.
92
93Parameters denoted with BOOT are actually interpreted by the boot
94loader, and have no meaning to the kernel directly.
95Do not modify the syntax of boot loader parameters without extreme
96need or coordination with <Documentation/i386/boot.txt>.
97
98Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
99a trailing = on the name of any parameter states that that parameter will
100be entered as an environment variable, whereas its absence indicates that
101it will appear as a kernel argument readable via /proc/cmdline by programs
102running once the system is up.
103
104 53c7xx= [HW,SCSI] Amiga SCSI controllers
105 See header of drivers/scsi/53c7xx.c.
106 See also Documentation/scsi/ncr53c7xx.txt.
107
a9913044
RD
108 acpi= [HW,ACPI] Advanced Configuration and Power Interface
109 Format: { force | off | ht | strict | noirq }
1da177e4
LT
110 force -- enable ACPI if default was off
111 off -- disable ACPI if default was on
112 noirq -- do not use ACPI for IRQ routing
113 ht -- run only enough ACPI to enable Hyper Threading
a9913044 114 strict -- Be less tolerant of platforms that are not
1da177e4
LT
115 strictly ACPI specification compliant.
116
117 See also Documentation/pm.txt, pci=noacpi
118
119 acpi_sleep= [HW,ACPI] Sleep options
120 Format: { s3_bios, s3_mode }
121 See Documentation/power/video.txt
a9913044 122
1da177e4 123 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 124 Format: { level | edge | high | low }
1da177e4 125
a9913044
RD
126 acpi_irq_balance [HW,ACPI]
127 ACPI will balance active IRQs
128 default in APIC mode
1da177e4 129
a9913044
RD
130 acpi_irq_nobalance [HW,ACPI]
131 ACPI will not move active IRQs (default)
132 default in PIC mode
1da177e4 133
a9913044
RD
134 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
135 use by PCI
1da177e4
LT
136 Format: <irq>,<irq>...
137
a9913044 138 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
1da177e4
LT
139 Format: <irq>,<irq>...
140
141 acpi_osi= [HW,ACPI] empty param disables _OSI
142
143 acpi_serialize [HW,ACPI] force serialization of AML methods
144
145 acpi_skip_timer_override [HW,ACPI]
146 Recognize and ignore IRQ0/pin2 Interrupt Override.
147 For broken nForce2 BIOS resulting in XT-PIC timer.
148
149 acpi_dbg_layer= [HW,ACPI]
150 Format: <int>
a9913044 151 Each bit of the <int> indicates an ACPI debug layer,
1da177e4
LT
152 1: enable, 0: disable. It is useful for boot time
153 debugging. After system has booted up, it can be set
154 via /proc/acpi/debug_layer.
155
156 acpi_dbg_level= [HW,ACPI]
157 Format: <int>
a9913044 158 Each bit of the <int> indicates an ACPI debug level,
1da177e4
LT
159 1: enable, 0: disable. It is useful for boot time
160 debugging. After system has booted up, it can be set
161 via /proc/acpi/debug_level.
162
163 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
164
30e332f3
LY
165 acpi_generic_hotkey [HW,ACPI]
166 Allow consolidated generic hotkey driver to
a9913044 167 override platform specific driver.
30e332f3
LY
168 See also Documentation/acpi-hotkey.txt.
169
66759a01
CE
170 enable_timer_pin_1 [i386,x86-64]
171 Enable PIN 1 of APIC timer
a9913044
RD
172 Can be useful to work around chipset bugs
173 (in particular on some ATI chipsets).
66759a01
CE
174 The kernel tries to set a reasonable default.
175
176 disable_timer_pin_1 [i386,x86-64]
177 Disable PIN 1 of APIC timer
178 Can be useful to work around chipset bugs.
179
1da177e4
LT
180 ad1816= [HW,OSS]
181 Format: <io>,<irq>,<dma>,<dma2>
182 See also Documentation/sound/oss/AD1816.
183
184 ad1848= [HW,OSS]
185 Format: <io>,<irq>,<dma>,<dma2>,<type>
186
187 adlib= [HW,OSS]
188 Format: <io>
a9913044 189
1da177e4
LT
190 advansys= [HW,SCSI]
191 See header of drivers/scsi/advansys.c.
192
193 advwdt= [HW,WDT] Advantech WDT
194 Format: <iostart>,<iostop>
195
196 aedsp16= [HW,OSS] Audio Excel DSP 16
197 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
198 See also header of sound/oss/aedsp16.c.
a9913044 199
1da177e4
LT
200 aha152x= [HW,SCSI]
201 See Documentation/scsi/aha152x.txt.
202
203 aha1542= [HW,SCSI]
204 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
205
206 aic7xxx= [HW,SCSI]
207 See Documentation/scsi/aic7xxx.txt.
208
209 aic79xx= [HW,SCSI]
210 See Documentation/scsi/aic79xx.txt.
211
1da177e4
LT
212 amijoy.map= [HW,JOY] Amiga joystick support
213 Map of devices attached to JOY0DAT and JOY1DAT
214 Format: <a>,<b>
215 See also Documentation/kernel/input/joystick.txt
216
217 analog.map= [HW,JOY] Analog joystick and gamepad support
218 Specifies type or capabilities of an analog joystick
219 connected to one of 16 gameports
220 Format: <type1>,<type2>,..<type16>
221
a9913044
RD
222 apc= [HW,SPARC]
223 Power management functions (SPARCstation-4/5 + deriv.)
1da177e4
LT
224 Format: noidle
225 Disable APC CPU standby support. SPARCstation-Fox does
226 not play well with APC CPU idle - disable it if you have
227 APC and your system crashes randomly.
228
a9913044 229 apic= [APIC,i386] Change the output verbosity whilst booting
1da177e4
LT
230 Format: { quiet (default) | verbose | debug }
231 Change the amount of debugging information output
232 when initialising the APIC and IO-APIC components.
a9913044 233
1da177e4
LT
234 apm= [APM] Advanced Power Management
235 See header of arch/i386/kernel/apm.c.
236
237 applicom= [HW]
238 Format: <mem>,<irq>
a9913044 239
1da177e4
LT
240 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
241 Format: <io>,<irq>,<nodeID>
242
243 ataflop= [HW,M68k]
244
245 atarimouse= [HW,MOUSE] Atari Mouse
246
247 atascsi= [HW,SCSI] Atari SCSI
248
249 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
250 EzKey and similar keyboards
251
252 atkbd.reset= [HW] Reset keyboard during initialization
253
a9913044
RD
254 atkbd.set= [HW] Select keyboard code set
255 Format: <int> (2 = AT (default), 3 = PS/2)
1da177e4
LT
256
257 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
258 keyboards
259
260 atkbd.softraw= [HW] Choose between synthetic and real raw mode
261 Format: <bool> (0 = real, 1 = synthetic (default))
a9913044
RD
262
263 atkbd.softrepeat= [HW]
264 Use software keyboard repeat
1da177e4
LT
265
266 autotest [IA64]
267
268 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
269 Format: <io>,<memsize>,<isapnp>
a9913044 270
1da177e4
LT
271 aztcd= [HW,CD] Aztech CD268 CDROM driver
272 Format: <io>,0x79 (?)
273
274 baycom_epp= [HW,AX25]
275 Format: <io>,<mode>
a9913044 276
1da177e4
LT
277 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
278 Format: <io>,<mode>
279 See header of drivers/net/hamradio/baycom_par.c.
280
a9913044
RD
281 baycom_ser_fdx= [HW,AX25]
282 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
1da177e4
LT
283 Format: <io>,<irq>,<mode>[,<baud>]
284 See header of drivers/net/hamradio/baycom_ser_fdx.c.
285
a9913044
RD
286 baycom_ser_hdx= [HW,AX25]
287 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
1da177e4
LT
288 Format: <io>,<irq>,<mode>
289 See header of drivers/net/hamradio/baycom_ser_hdx.c.
290
291 blkmtd_device= [HW,MTD]
292 blkmtd_erasesz=
293 blkmtd_ro=
294 blkmtd_bs=
295 blkmtd_count=
296
297 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
a9913044
RD
298 bttv.radio= Most important insmod options are available as
299 kernel args too.
1da177e4
LT
300 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
301 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
302
303 BusLogic= [HW,SCSI]
304 See drivers/scsi/BusLogic.c, comment before function
305 BusLogic_ParseDriverOptions().
306
307 c101= [NET] Moxa C101 synchronous serial card
308
309 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
310 Sometimes CPU hardware bugs make them report the cache
311 size incorrectly. The kernel will attempt work arounds
312 to fix known problems, but for some CPUs it is not
313 possible to determine what the correct size should be.
314 This option provides an override for these situations.
315
316 cdu31a= [HW,CD]
317 Format: <io>,<irq>[,PAS]
318 See header of drivers/cdrom/cdu31a.c.
319
320 chandev= [HW,NET] Generic channel device initialisation
321
322 checkreqprot [SELINUX] Set initial checkreqprot flag value.
323 Format: { "0" | "1" }
324 See security/selinux/Kconfig help text.
a9913044
RD
325 0 -- check protection applied by kernel (includes
326 any implied execute protection).
1da177e4
LT
327 1 -- check protection requested by application.
328 Default value is set via a kernel config option.
a9913044
RD
329 Value can be changed at runtime via
330 /selinux/checkreqprot.
331
332 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
1da177e4 333 Forces specified timesource (if avaliable) to be used
a9913044
RD
334 when calculating gettimeofday(). If specicified
335 timesource is not avalible, it defaults to PIT.
1da177e4
LT
336 Format: { pit | tsc | cyclone | pmtmr }
337
338 hpet= [IA-32,HPET] option to disable HPET and use PIT.
339 Format: disable
340
341 cm206= [HW,CD]
342 Format: { auto | [<io>,][<irq>] }
343
344 com20020= [HW,NET] ARCnet - COM20020 chipset
a9913044
RD
345 Format:
346 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
1da177e4
LT
347
348 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
349 Format: <io>[,<irq>]
350
a9913044
RD
351 com90xx= [HW,NET]
352 ARCnet - COM90xx chipset (memory-mapped buffers)
1da177e4
LT
353 Format: <io>[,<irq>[,<memstart>]]
354
355 condev= [HW,S390] console device
356 conmode=
a9913044 357
1da177e4
LT
358 console= [KNL] Output console device and options.
359
360 tty<n> Use the virtual console device <n>.
361
362 ttyS<n>[,options]
363 Use the specified serial port. The options are of
364 the form "bbbbpn", where "bbbb" is the baud rate,
365 "p" is parity ("n", "o", or "e"), and "n" is bits.
366 Default is "9600n8".
367
368 See also Documentation/serial-console.txt.
369
370 uart,io,<addr>[,options]
371 uart,mmio,<addr>[,options]
372 Start an early, polled-mode console on the 8250/16550
373 UART at the specified I/O port or MMIO address,
374 switching to the matching ttyS device later. The
375 options are the same as for ttyS, above.
376
377 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
a9913044
RD
378 Format:
379 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
1da177e4
LT
380
381 cpia_pp= [HW,PPT]
382 Format: { parport<nr> | auto | none }
383
dc009d92
EB
384 crashkernel=nn[KMG]@ss[KMG]
385 [KNL] Reserve a chunk of physical memory to
386 hold a kernel to switch to with kexec on panic.
387
1da177e4
LT
388 cs4232= [HW,OSS]
389 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
390
391 cs89x0_dma= [HW,NET]
392 Format: <dma>
393
394 cs89x0_media= [HW,NET]
395 Format: { rj45 | aui | bnc }
a9913044 396
1da177e4 397 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
a9913044
RD
398
399 dasd= [HW,NET]
1da177e4
LT
400 See header of drivers/s390/block/dasd_devmap.c.
401
402 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
403 (one device per port)
404 Format: <port#>,<type>
405 See also Documentation/input/joystick-parport.txt
406
407 debug [KNL] Enable kernel debugging (events log level).
408
409 decnet= [HW,NET]
410 Format: <area>[,<node>]
411 See also Documentation/networking/decnet.txt.
412
413 devfs= [DEVFS]
414 See Documentation/filesystems/devfs/boot-options.
415
416 dhash_entries= [KNL]
417 Set number of hash buckets for dentry cache.
a9913044 418
1da177e4
LT
419 digi= [HW,SERIAL]
420 IO parameters + enable/disable command.
421
422 digiepca= [HW,SERIAL]
423 See drivers/char/README.epca and
424 Documentation/digiepca.txt.
425
426 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
427 support available.
428 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
429
430 dmasound= [HW,OSS] Sound subsystem buffers
431
432 dscc4.setup= [NET]
433
434 dtc3181e= [HW,SCSI]
435
a9913044 436 earlyprintk= [IA-32,X86-64]
1da177e4
LT
437 earlyprintk=vga
438 earlyprintk=serial[,ttySn[,baudrate]]
439
a9913044 440 Append ",keep" to not disable it when the real console
1da177e4
LT
441 takes over.
442
443 Only vga or serial at a time, not both.
444
445 Currently only ttyS0 and ttyS1 are supported.
446
447 Interaction with the standard serial driver is not
448 very good.
449
450 The VGA output is eventually overwritten by the real
451 console.
452
453 eata= [HW,SCSI]
454
53f11d4f
LB
455 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
456 Format: <int>
457 0: polling mode
458 non-0: interrupt mode (default)
459
1da177e4
LT
460 eda= [HW,PS2]
461
462 edb= [HW,PS2]
463
464 edd= [EDD]
465 Format: {"of[f]" | "sk[ipmbr]"}
466 See comment in arch/i386/boot/edd.S
467
a9913044 468 eicon= [HW,ISDN]
1da177e4
LT
469 Format: <id>,<membase>,<irq>
470
471 eisa_irq_edge= [PARISC,HW]
472 See header of drivers/parisc/eisa.c.
473
474 elanfreq= [IA-32]
475 See comment before function elanfreq_setup() in
476 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
477
478 elevator= [IOSCHED]
16ab3adf 479 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
a9913044
RD
480 See Documentation/block/as-iosched.txt and
481 Documentation/block/deadline-iosched.txt for details.
482
aac04b32 483 elfcorehdr= [IA-32, X86_64]
a9913044 484 Specifies physical address of start of kernel core
aac04b32
VG
485 image elf header. Generally kexec loader will
486 pass this option to capture kernel.
487 See Documentation/kdump/kdump.txt for details.
1da177e4
LT
488
489 enforcing [SELINUX] Set initial enforcing status.
490 Format: {"0" | "1"}
491 See security/selinux/Kconfig help text.
492 0 -- permissive (log only, no denials).
493 1 -- enforcing (deny and log).
494 Default value is 0.
495 Value can be changed at runtime via /selinux/enforce.
496
497 es1370= [HW,OSS]
498 Format: <lineout>[,<micbias>]
499 See also header of sound/oss/es1370.c.
500
501 es1371= [HW,OSS]
502 Format: <spdif>,[<nomix>,[<amplifier>]]
503 See also header of sound/oss/es1371.c.
a9913044 504
1da177e4
LT
505 ether= [HW,NET] Ethernet cards parameters
506 This option is obsoleted by the "netdev=" option, which
507 has equivalent usage. See its documentation for details.
508
509 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
510 Format: <io>[,<irq>]
511
512 fd_mcs= [HW,SCSI]
513 See header of drivers/scsi/fd_mcs.c.
514
515 fdomain= [HW,SCSI]
516 See header of drivers/scsi/fdomain.c.
517
518 floppy= [HW]
519 See Documentation/floppy.txt.
520
521 ftape= [HW] Floppy Tape subsystem debugging options.
522 See Documentation/ftape.txt.
523
524 gamecon.map[2|3]=
525 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
526 support via parallel port (up to 5 devices per port)
527 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
528 See also Documentation/input/joystick-parport.txt
529
530 gamma= [HW,DRM]
531
532 gdth= [HW,SCSI]
533 See header of drivers/scsi/gdth.c.
534
535 gpt [EFI] Forces disk with valid GPT signature but
536 invalid Protective MBR to be treated as GPT.
537
538 gscd= [HW,CD]
539 Format: <io>
540
541 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
542
543 gus= [HW,OSS]
544 Format: <io>,<irq>,<dma>,<dma16>
a9913044 545
1da177e4
LT
546 gvp11= [HW,SCSI]
547
548 hashdist= [KNL,NUMA] Large hashes allocated during boot
549 are distributed across NUMA nodes. Defaults on
550 for IA-64, off otherwise.
a9913044 551 Format: 0 | 1 (for off | on)
1da177e4
LT
552
553 hcl= [IA-64] SGI's Hardware Graph compatibility layer
554
555 hd= [EIDE] (E)IDE hard drive subsystem geometry
556 Format: <cyl>,<head>,<sect>
557
558 hd?= [HW] (E)IDE subsystem
559 hd?lun= See Documentation/ide.txt.
560
561 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
562 size of <nn>. This works even on boxes that have no
563 highmem otherwise. This also works to reduce highmem
564 size on bigger boxes.
565
566 hisax= [HW,ISDN]
567 See Documentation/isdn/README.HiSax.
568
569 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
570
571 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
572
573 i8042.direct [HW] Put keyboard port into non-translated mode
574 i8042.dumbkbd [HW] Pretend that controlled can only read data from
575 keyboard and can not control its state
576 (Don't attempt to blink the leds)
577 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 578 i8042.nokbd [HW] Don't check/create keyboard port
1da177e4
LT
579 i8042.nomux [HW] Don't check presence of an active multiplexing
580 controller
581 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
582 controllers
583 i8042.panicblink=
584 [HW] Frequency with which keyboard LEDs should blink
585 when kernel panics (default is 0.5 sec)
586 i8042.reset [HW] Reset the controller during init and cleanup
587 i8042.unlock [HW] Unlock (ignore) the keylock
588
589 i810= [HW,DRM]
590
e70c9d5e
DT
591 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
592 indicates that the driver is running on unsupported
593 hardware.
1da177e4
LT
594 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
595 does not match list of supported models.
596 i8k.power_status
597 [HW] Report power status in /proc/i8k
598 (disabled by default)
599 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
600 capability is set.
601
602 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
603 See Documentation/mca.txt.
604
605 icn= [HW,ISDN]
606 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
607
608 ide= [HW] (E)IDE subsystem
609 Format: ide=nodma or ide=doubler or ide=reverse
610 See Documentation/ide.txt.
611
612 ide?= [HW] (E)IDE subsystem
613 Format: ide?=noprobe or chipset specific parameters.
614 See Documentation/ide.txt.
a9913044 615
1da177e4
LT
616 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
617 See Documentation/ide.txt.
618
619 idle= [HW]
620 Format: idle=poll or idle=halt
a9913044 621
1da177e4
LT
622 ihash_entries= [KNL]
623 Set number of hash buckets for inode cache.
624
625 in2000= [HW,SCSI]
626 See header of drivers/scsi/in2000.c.
627
628 init= [KNL]
629 Format: <full_path>
630 Run specified binary instead of /sbin/init as init
631 process.
632
633 initcall_debug [KNL] Trace initcalls as they are executed. Useful
634 for working out where the kernel is dying during
635 startup.
636
637 initrd= [BOOT] Specify the location of the initial ramdisk
638
639 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
640 Format: <irq>
641
2bd0fa3b
JB
642 combined_mode= [HW] control which driver uses IDE ports in combined
643 mode: legacy IDE driver, libata, or both
644 (in the libata case, libata.atapi_enabled=1 may be
645 useful as well). Note that using the ide or libata
646 options may affect your device naming (e.g. by
647 changing hdc to sdb).
648 Format: combined (default), ide, or libata
649
1da177e4
LT
650 inttest= [IA64]
651
652 io7= [HW] IO7 for Marvel based alpha systems
653 See comment before marvel_specify_io7 in
654 arch/alpha/kernel/core_marvel.c.
655
656 ip= [IP_PNP]
657 See Documentation/nfsroot.txt.
658
659 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
660 See comment before ip2_setup() in drivers/char/ip2.c.
661
662 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
663 See header of drivers/scsi/ips.c.
664
200803df
AC
665 irqfixup [HW]
666 When an interrupt is not handled search all handlers
667 for it. Intended to get systems with badly broken
668 firmware running.
669
670 irqpoll [HW]
671 When an interrupt is not handled search all handlers
672 for it. Also check all handlers each timer
673 interrupt. Intended to get systems with badly broken
674 firmware running.
675
1da177e4 676 isapnp= [ISAPNP]
a9913044 677 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
678
679 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
680 Format: <cpu number>,...,<cpu number>
681 This option can be used to specify one or more CPUs
682 to isolate from the general SMP balancing and scheduling
683 algorithms. The only way to move a process onto or off
684 an "isolated" CPU is via the CPU affinity syscalls.
685 <cpu number> begins at 0 and the maximum value is
686 "number of CPUs in system - 1".
687
688 This option is the preferred way to isolate CPUs. The
a9913044
RD
689 alternative -- manually setting the CPU mask of all
690 tasks in the system -- can cause problems and
691 suboptimal load balancer performance.
1da177e4
LT
692
693 isp16= [HW,CD]
694 Format: <io>,<irq>,<dma>,<setup>
695
a9913044 696 iucv= [HW,NET]
1da177e4
LT
697
698 js= [HW,JOY] Analog joystick
699 See Documentation/input/joystick.txt.
700
701 keepinitrd [HW,ARM]
702
a9913044 703 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
704 in oops dumps.
705
706 l2cr= [PPC]
707
a9913044
RD
708 lapic [IA-32,APIC] Enable the local APIC even if BIOS
709 disabled it.
1da177e4
LT
710
711 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
712 Format: addr:<io>,irq:<irq>
713
a9913044
RD
714 llsc*= [IA64] See function print_params() in
715 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
716
717 load_ramdisk= [RAM] List of ramdisks to load from floppy
718 See Documentation/ramdisk.txt.
719
a6b25b67
RD
720 lockd.nlm_grace_period=P [NFS] Assign grace period.
721 Format: <integer>
1da177e4 722
a6b25b67
RD
723 lockd.nlm_tcpport=N [NFS] Assign TCP port.
724 Format: <integer>
725
726 lockd.nlm_timeout=T [NFS] Assign timeout value.
727 Format: <integer>
728
729 lockd.nlm_udpport=M [NFS] Assign UDP port.
730 Format: <integer>
1da177e4
LT
731
732 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
733 Format: <irq>
734
735 loglevel= All Kernel Messages with a loglevel smaller than the
736 console loglevel will be printed to the console. It can
737 also be changed with klogd or other programs. The
738 loglevels are defined as follows:
739
740 0 (KERN_EMERG) system is unusable
741 1 (KERN_ALERT) action must be taken immediately
742 2 (KERN_CRIT) critical conditions
743 3 (KERN_ERR) error conditions
744 4 (KERN_WARNING) warning conditions
745 5 (KERN_NOTICE) normal but significant condition
746 6 (KERN_INFO) informational
747 7 (KERN_DEBUG) debug-level messages
748
749 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
750 Format: { n | nk | nM }
751 n must be a power of two. The default size
752 is set in the kernel config file.
1da177e4
LT
753
754 lp=0 [LP] Specify parallel ports to use, e.g,
755 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
756 lp=reset first parallel port). 'lp=0' disables the
757 lp=auto printer driver. 'lp=reset' (which can be
758 specified in addition to the ports) causes
759 attached printers to be reset. Using
760 lp=port1,port2,... specifies the parallel ports
761 to associate lp devices with, starting with
762 lp0. A port specification may be 'none' to skip
763 that lp device, or a parport name such as
764 'parport0'. Specifying 'lp=auto' instead of a
765 port specification list means that device IDs
766 from each port should be examined, to see if
767 an IEEE 1284-compliant printer is attached; if
768 so, the driver will manage that printer.
769 See also header of drivers/char/lp.c.
770
771 lpj=n [KNL]
772 Sets loops_per_jiffy to given constant, thus avoiding
773 time-consuming boot-time autodetection (up to 250 ms per
774 CPU). 0 enables autodetection (default). To determine
775 the correct value for your kernel, boot with normal
776 autodetection and see what value is printed. Note that
777 on SMP systems the preset will be applied to all CPUs,
778 which is likely to cause problems if your CPUs need
779 significantly divergent settings. An incorrect value
780 will cause delays in the kernel to be wrong, leading to
781 unpredictable I/O errors and other breakage. Although
782 unlikely, in the extreme case this might damage your
783 hardware.
784
785 ltpc= [NET]
786 Format: <io>,<irq>,<dma>
787
a9913044
RD
788 mac5380= [HW,SCSI] Format:
789 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 790
a9913044
RD
791 mac53c9x= [HW,SCSI] Format:
792 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 793
a9913044
RD
794 machvec= [IA64] Force the use of a particular machine-vector
795 (machvec) in a generic kernel.
796 Example: machvec=hpzx1_swiotlb
1da177e4 797
a9913044
RD
798 mad16= [HW,OSS] Format:
799 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
800
801 maui= [HW,OSS]
802 Format: <io>,<irq>
a9913044
RD
803
804 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
805 be mounted
806 Format: <1-256>
807
808 maxcpus= [SMP] Maximum number of processors that an SMP kernel
809 should make use of
810
2b2c3750
BP
811 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
812 equal to this physical address is ignored.
813
a9913044 814 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
815 Should be between 1 and 2^32-1.
816
817 max_report_luns=
a9913044 818 [SCSI] Maximum number of LUNs received.
1da177e4
LT
819 Should be between 1 and 16384.
820
821 mca-pentium [BUGS=IA-32]
822
823 mcatest= [IA-64]
824
825 mcd= [HW,CD]
826 Format: <port>,<irq>,<mitsumi_bug_93_wait>
827
828 mcdx= [HW,CD]
829
830 mce [IA-32] Machine Check Exception
831
832 md= [HW] RAID subsystems devices and level
833 See Documentation/md.txt.
a9913044 834
1da177e4
LT
835 mdacon= [MDA]
836 Format: <first>,<last>
837 Specifies range of consoles to be captured by the MDA.
a9913044 838
1da177e4
LT
839 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
840 Amount of memory to be used when the kernel is not able
841 to see the whole system memory or for test.
842 [IA-32] Use together with memmap= to avoid physical
843 address space collisions. Without memmap= PCI devices
844 could be placed at addresses belonging to unused RAM.
845
846 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
847 memory.
848
69cda7b1 849 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
850 E820 memory map, as specified by the user.
851 Such memmap=exactmap lines can be constructed based on
852 BIOS output or other requirements. See the memmap=nn@ss
853 option description.
854
855 memmap=nn[KMG]@ss[KMG]
856 [KNL] Force usage of a specific region of memory
857 Region of memory to be used, from ss to ss+nn.
858
859 memmap=nn[KMG]#ss[KMG]
860 [KNL,ACPI] Mark specific memory as ACPI data.
861 Region of memory to be used, from ss to ss+nn.
862
863 memmap=nn[KMG]$ss[KMG]
864 [KNL,ACPI] Mark specific memory as reserved.
865 Region of memory to be used, from ss to ss+nn.
866
867 meye.*= [HW] Set MotionEye Camera parameters
868 See Documentation/video4linux/meye.txt.
869
870 mga= [HW,DRM]
871
198e2f18 872 migration_cost=
873 [KNL,SMP] debug: override scheduler migration costs
874 Format: <level-1-usecs>,<level-2-usecs>,...
875 This debugging option can be used to override the
876 default scheduler migration cost matrix. The numbers
877 are indexed by 'CPU domain distance'.
878 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
879 box will set up an intra-core migration cost of
880 1 msec, an inter-core migration cost of 2 msecs,
881 and an inter-node migration cost of 3 msecs.
882
883 WARNING: using the wrong values here can break
884 scheduler performance, so it's only for scheduler
885 development purposes, not production environments.
886
887 migration_debug=
888 [KNL,SMP] migration cost auto-detect verbosity
889 Format=<0|1|2>
890 If a system's migration matrix reported at bootup
891 seems erroneous then this option can be used to
892 increase verbosity of the detection process.
893 We default to 0 (no extra messages), 1 will print
894 some more information, and 2 will be really
895 verbose (probably only useful if you also have a
896 serial console attached to the system).
897
898 migration_factor=
899 [KNL,SMP] multiply/divide migration costs by a factor
900 Format=<percent>
901 This debug option can be used to proportionally
902 increase or decrease the auto-detected migration
903 costs for all entries of the migration matrix.
904 E.g. migration_factor=150 will increase migration
905 costs by 50%. (and thus the scheduler will be less
906 eager migrating cache-hot tasks)
907 migration_factor=80 will decrease migration costs
908 by 20%. (thus the scheduler will be more eager to
909 migrate tasks)
910
911 WARNING: using the wrong values here can break
912 scheduler performance, so it's only for scheduler
913 development purposes, not production environments.
914
1da177e4
LT
915 mousedev.tap_time=
916 [MOUSE] Maximum time between finger touching and
917 leaving touchpad surface for touch to be considered
918 a tap and be reported as a left button click (for
919 touchpads working in absolute mode only).
920 Format: <msecs>
921 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
922 reporting absolute coordinates, such as tablets
923 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
924 reporting absolute coordinates, such as tablets
925
926 mpu401= [HW,OSS]
927 Format: <io>,<irq>
928
929 MTD_Partition= [MTD]
930 Format: <name>,<region-number>,<size>,<offset>
931
a9913044
RD
932 MTD_Region= [MTD] Format:
933 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
934
935 mtdparts= [MTD]
936 See drivers/mtd/cmdline.c.
937
938 mtouchusb.raw_coordinates=
a9913044
RD
939 [HW] Make the MicroTouch USB driver use raw coordinates
940 ('y', default) or cooked coordinates ('n')
1da177e4
LT
941
942 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
943
944 NCR_D700= [HW,SCSI]
945 See header of drivers/scsi/NCR_D700.c.
946
947 ncr5380= [HW,SCSI]
948
949 ncr53c400= [HW,SCSI]
950
951 ncr53c400a= [HW,SCSI]
952
953 ncr53c406a= [HW,SCSI]
954
955 ncr53c8xx= [HW,SCSI]
956
957 netdev= [NET] Network devices parameters
958 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
959 Note that mem_start is often overloaded to mean
960 something different and driver-specific.
a9913044
RD
961 This usage is only documented in each driver source
962 file if at all.
963
1da177e4
LT
964 nfsaddrs= [NFS]
965 See Documentation/nfsroot.txt.
966
967 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
968 See Documentation/nfsroot.txt.
969
a72b4422
TM
970 nfs.callback_tcpport=
971 [NFS] set the TCP port on which the NFSv4 callback
972 channel should listen.
973
58df095b
TM
974 nfs.idmap_cache_timeout=
975 [NFS] set the maximum lifetime for idmapper cache
976 entries.
977
1da177e4
LT
978 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
979
980 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
981 emulation library even if a 387 maths coprocessor
982 is present.
983
a9913044
RD
984 noalign [KNL,ARM]
985
1da177e4
LT
986 noapic [SMP,APIC] Tells the kernel to not make use of any
987 IOAPICs that may be present in the system.
988
989 noasync [HW,M68K] Disables async and sync negotiation for
990 all devices.
991
992 nobats [PPC] Do not use BATs for mapping kernel lowmem
993 on "Classic" PPC cores.
994
995 nocache [ARM]
a9913044 996
1da177e4
LT
997 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
998
999 noexec [IA-64]
1000
a9913044 1001 noexec [IA-32,X86-64]
1da177e4
LT
1002 noexec=on: enable non-executable mappings (default)
1003 noexec=off: disable nn-executable mappings
1004
1005 nofxsr [BUGS=IA-32]
1006
1007 nohlt [BUGS=ARM]
a9913044 1008
1da177e4
LT
1009 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1010 instruction doesn't work correctly and not to
1011 use it.
1012
1013 nohalt [IA-64] Tells the kernel not to use the power saving
1014 function PAL_HALT_LIGHT when idle. This increases
1015 power-consumption. On the positive side, it reduces
1016 interrupt wake-up latency, which may improve performance
1017 in certain environments such as networked servers or
1018 real-time systems.
1019
1020 noirqdebug [IA-32] Disables the code which attempts to detect and
1021 disable unhandled interrupt sources.
1022
1023 noisapnp [ISAPNP] Disables ISA PnP code.
1024
1025 noinitrd [RAM] Tells the kernel not to load any configured
1026 initial RAM disk.
1027
1028 nointroute [IA-64]
1029
1030 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1031
1032 noltlbs [PPC] Do not use large page/tlb entries for kernel
1033 lowmem mapping on PPC40x.
1034
1035 nomce [IA-32] Machine Check Exception
1036
312f1f01
H
1037 nomca [IA-64] Disable machine check abort handling
1038
1da177e4
LT
1039 noresidual [PPC] Don't use residual data on PReP machines.
1040
a9913044
RD
1041 noresume [SWSUSP] Disables resume and restores original swap
1042 space.
1043
1da177e4
LT
1044 no-scroll [VGA] Disables scrollback.
1045 This is required for the Braillex ib80-piezo Braille
1046 reader made by F.H. Papenmeier (Germany).
1047
1048 nosbagart [IA-64]
1049
1050 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1051
1052 nosync [HW,M68K] Disables sync negotiation for all devices.
1053
1054 notsc [BUGS=IA-32] Disable Time Stamp Counter
1055
1056 nousb [USB] Disable the USB subsystem
1057
1058 nowb [ARM]
a9913044 1059
a61c2d78
DJ
1060 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1061
1da177e4
LT
1062 opl3= [HW,OSS]
1063 Format: <io>
1064
1065 opl3sa= [HW,OSS]
1066 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1067
a9913044
RD
1068 opl3sa2= [HW,OSS] Format:
1069 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1070
1da177e4
LT
1071 oprofile.timer= [HW]
1072 Use timer interrupt instead of performance counters
1073
1074 optcd= [HW,CD]
1075 Format: <io>
1076
1077 osst= [HW,SCSI] SCSI Tape Driver
1078 Format: <buffer_size>,<write_threshold>
1079 See also Documentation/scsi/st.txt.
1080
1081 panic= [KNL] Kernel behaviour on panic
1082 Format: <timeout>
1083
1084 parkbd.port= [HW] Parallel port number the keyboard adapter is
1085 connected to, default is 0.
1086 Format: <parport#>
1087 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1088 0 for XT, 1 for AT (default is AT).
a9913044
RD
1089 Format: <mode>
1090
1091 parport= [HW,PPT] Specify parallel ports. 0 disables.
1092 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1093 Use 'auto' to force the driver to use any
1094 IRQ/DMA settings detected (the default is to
1095 ignore detected IRQ/DMA settings because of
1096 possible conflicts). You can specify the base
1097 address, IRQ, and DMA settings; IRQ and DMA
1098 should be numbers, or 'auto' (for using detected
1099 settings on that particular port), or 'nofifo'
1100 (to avoid using a FIFO even if it is detected).
1101 Parallel ports are assigned in the order they
1102 are specified on the command line, starting
1103 with parport0.
1104
1105 parport_init_mode= [HW,PPT]
1106 Configure VIA parallel port to operate in
1107 a specific mode. This is necessary on Pegasos
1108 computer where firmware has no options for setting
1109 up parallel port mode and sets it to spp.
1110 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1111 Format: [spp|ps2|epp|ecp|ecpepp]
1112
a9913044
RD
1113 pas2= [HW,OSS] Format:
1114 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1115
1da177e4
LT
1116 pas16= [HW,SCSI]
1117 See header of drivers/scsi/pas16.c.
1118
1119 pcbit= [HW,ISDN]
1120
1121 pcd. [PARIDE]
1122 See header of drivers/block/paride/pcd.c.
1123 See also Documentation/paride.txt.
1124
a9913044
RD
1125 pci=option[,option...] [PCI] various PCI subsystem options:
1126 off [IA-32] don't probe for the PCI bus
1127 bios [IA-32] force use of PCI BIOS, don't access
1128 the hardware directly. Use this if your machine
1129 has a non-standard PCI host bridge.
1130 nobios [IA-32] disallow use of PCI BIOS, only direct
1131 hardware access methods are allowed. Use this
1132 if you experience crashes upon bootup and you
1133 suspect they are caused by the BIOS.
1134 conf1 [IA-32] Force use of PCI Configuration
1135 Mechanism 1.
1136 conf2 [IA-32] Force use of PCI Configuration
1137 Mechanism 2.
61be6d66
BH
1138 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1139 Configuration
a9913044
RD
1140 nosort [IA-32] Don't sort PCI devices according to
1141 order given by the PCI BIOS. This sorting is
1142 done to get a device order compatible with
1143 older kernels.
1144 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1145 routing table. These calls are known to be buggy
1146 on several machines and they hang the machine
1147 when used, but on other computers it's the only
1148 way to get the interrupt routing table. Try
1149 this option if the kernel is unable to allocate
1150 IRQs or discover secondary PCI buses on your
1151 motherboard.
1152 rom [IA-32] Assign address space to expansion ROMs.
1153 Use with caution as certain devices share
1154 address decoders between ROMs and other
1155 resources.
1156 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1157 assigned automatically to PCI devices. You can
1158 make the kernel exclude IRQs of your ISA cards
1159 this way.
120bb424 1160 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1161 of the PIRQ table (normally generated
1162 by the BIOS) if it is outside the
1163 F0000h-100000h range.
1164 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1165 useful if the kernel is unable to find your
1166 secondary buses and you want to tell it
1167 explicitly which ones they are.
1168 assign-busses [IA-32] Always assign all PCI bus
1169 numbers ourselves, overriding
1170 whatever the firmware may have done.
1171 usepirqmask [IA-32] Honor the possible IRQ mask stored
1172 in the BIOS $PIR table. This is needed on
1173 some systems with broken BIOSes, notably
1174 some HP Pavilion N5400 and Omnibook XE3
1175 notebooks. This will have no effect if ACPI
1176 IRQ routing is enabled.
1177 noacpi [IA-32] Do not use ACPI for IRQ routing
1178 or for PCI scanning.
1179 routeirq Do IRQ routing for all PCI devices.
1180 This is normally done in pci_enable_device(),
1181 so this option is a temporary workaround
1182 for broken drivers that don't call it.
1183 firmware [ARM] Do not re-enumerate the bus but instead
1184 just use the configuration from the
1185 bootloader. This is currently used on
1186 IXP2000 systems where the bus has to be
1187 configured a certain way for adjunct CPUs.
1da177e4
LT
1188
1189 pcmv= [HW,PCMCIA] BadgePAD 4
1190
1191 pd. [PARIDE]
1192 See Documentation/paride.txt.
1193
1194 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1195 boot time.
1196 Format: { 0 | 1 }
1197 See arch/parisc/kernel/pdc_chassis.c
1198
1199 pf. [PARIDE]
1200 See Documentation/paride.txt.
1201
1202 pg. [PARIDE]
1203 See Documentation/paride.txt.
1204
1205 pirq= [SMP,APIC] Manual mp-table setup
1206 See Documentation/i386/IO-APIC.txt.
1207
1208 plip= [PPT,NET] Parallel port network link
1209 Format: { parport<nr> | timid | 0 }
1210 See also Documentation/parport.txt.
1211
1212 pnpacpi= [ACPI]
1213 { off }
1214
1215 pnpbios= [ISAPNP]
1216 { on | off | curr | res | no-curr | no-res }
1217
1218 pnp_reserve_irq=
1219 [ISAPNP] Exclude IRQs for the autoconfiguration
1220
1221 pnp_reserve_dma=
1222 [ISAPNP] Exclude DMAs for the autoconfiguration
1223
1224 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1225 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1226
1227 pnp_reserve_mem=
a9913044
RD
1228 [ISAPNP] Exclude memory regions for the
1229 autoconfiguration.
1da177e4
LT
1230 Ranges are in pairs (memory base and size).
1231
1232 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1233 Format: [schedule,]<number>
1234 Param: "schedule" - profile schedule points.
1235 Param: <number> - step/bucket size as a power of 2 for
1236 statistical time based profiling.
1da177e4 1237
a9913044 1238 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1239 Limit processor to maximum C-state
1240 max_cstate=9 overrides any DMI blacklist limit.
1241
41c0d868
LB
1242 processor.nocst [HW,ACPI]
1243 Ignore the _CST method to determine C-states,
1244 instead using the legacy FADT method
1245
1da177e4
LT
1246 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1247 before loading.
1248 See Documentation/ramdisk.txt.
1249
a9913044
RD
1250 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1251 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1252 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1253 per second.
a9913044
RD
1254 psmouse.resetafter= [HW,MOUSE]
1255 Try to reset the device after so many bad packets
1da177e4
LT
1256 (0 = never).
1257 psmouse.resolution=
1258 [HW,MOUSE] Set desired mouse resolution, in dpi.
1259 psmouse.smartscroll=
a9913044 1260 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1261 0 = disabled, 1 = enabled (default).
1262
1263 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1264 Format:
1265 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1266
1267 pt. [PARIDE]
1268 See Documentation/paride.txt.
1269
1270 quiet= [KNL] Disable log messages
a9913044 1271
1da177e4
LT
1272 r128= [HW,DRM]
1273
1274 raid= [HW,RAID]
1275 See Documentation/md.txt.
1276
1277 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1278 See Documentation/ramdisk.txt.
1279
a9913044 1280 ramdisk_blocksize= [RAM]
1da177e4 1281 See Documentation/ramdisk.txt.
a9913044 1282
1da177e4
LT
1283 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1284 New name for the ramdisk parameter.
1285 See Documentation/ramdisk.txt.
1286
ffdfc409
OJ
1287 rdinit= [KNL]
1288 Format: <full_path>
1289 Run specified binary instead of /init from the ramdisk,
1290 used for early userspace startup. See initrd.
1291
1da177e4
LT
1292 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1293 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1294 See arch/*/kernel/reboot.c.
1295
1296 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1297
a9913044
RD
1298 resume= [SWSUSP]
1299 Specify the partition device for software suspend
1da177e4
LT
1300
1301 rhash_entries= [KNL,NET]
1302 Set number of hash buckets for route cache
1303
1304 riscom8= [HW,SERIAL]
1305 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1306
1307 ro [KNL] Mount root device read-only on boot
1308
1309 root= [KNL] Root filesystem
1310
1311 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1312 mount the root filesystem
1313
1314 rootflags= [KNL] Set root filesystem mount option string
1315
1316 rootfstype= [KNL] Set root filesystem type
1317
1318 rw [KNL] Mount root device read-write on boot
1319
1320 S [KNL] Run init in single mode
1321
1322 sa1100ir [NET]
1323 See drivers/net/irda/sa1100_ir.c.
1324
1325 sb= [HW,OSS]
1326 Format: <io>,<irq>,<dma>,<dma2>
1327
1328 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1329
1da177e4
LT
1330 sbpcd= [HW,CD] Soundblaster CD adapter
1331 Format: <io>,<type>
1332 See a comment before function sbpcd_setup() in
1333 drivers/cdrom/sbpcd.c.
1334
1335 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1336 Format: <io>[,<timeout>[,<isapnp>]]
1337
1338 scsi_debug_*= [SCSI]
1339 See drivers/scsi/scsi_debug.c.
1340
1341 scsi_default_dev_flags=
1342 [SCSI] SCSI default device flags
1343 Format: <integer>
1344
1345 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1346 Format: <vendor>:<model>:<flags>
1347 (flags are integer value)
1348
1349 scsi_logging= [SCSI]
1350
1351 selinux [SELINUX] Disable or enable SELinux at boot time.
1352 Format: { "0" | "1" }
1353 See security/selinux/Kconfig help text.
1354 0 -- disable.
1355 1 -- enable.
1356 Default value is set via kernel config option.
1357 If enabled at boot time, /selinux/disable can be used
1358 later to disable prior to initial policy load.
1359
1360 serialnumber [BUGS=IA-32]
1361
a9913044
RD
1362 sg_def_reserved_size= [SCSI]
1363
1da177e4
LT
1364 sgalaxy= [HW,OSS]
1365 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1366
1367 shapers= [NET]
1368 Maximal number of shapers.
a9913044 1369
1da177e4
LT
1370 sim710= [SCSI,HW]
1371 See header of drivers/scsi/sim710.c.
1372
1373 simeth= [IA-64]
1374 simscsi=
a9913044 1375
1da177e4
LT
1376 sjcd= [HW,CD]
1377 Format: <io>,<irq>,<dma>
1378 See header of drivers/cdrom/sjcd.c.
1379
1380 slram= [HW,MTD]
1381
1382 smart2= [HW]
1383 Format: <io1>[,<io2>[,...,<io8>]]
1384
1385 snd-ad1816a= [HW,ALSA]
1386
1387 snd-ad1848= [HW,ALSA]
1388
1389 snd-ali5451= [HW,ALSA]
1390
1391 snd-als100= [HW,ALSA]
1392
1393 snd-als4000= [HW,ALSA]
1394
1395 snd-azt2320= [HW,ALSA]
1396
1397 snd-cmi8330= [HW,ALSA]
1398
1399 snd-cmipci= [HW,ALSA]
1400
1401 snd-cs4231= [HW,ALSA]
1402
1403 snd-cs4232= [HW,ALSA]
1404
1405 snd-cs4236= [HW,ALSA]
1406
1407 snd-cs4281= [HW,ALSA]
1408
1409 snd-cs46xx= [HW,ALSA]
1410
1411 snd-dt019x= [HW,ALSA]
1412
1413 snd-dummy= [HW,ALSA]
1414
1415 snd-emu10k1= [HW,ALSA]
1416
1417 snd-ens1370= [HW,ALSA]
1418
1419 snd-ens1371= [HW,ALSA]
1420
1421 snd-es968= [HW,ALSA]
1422
1423 snd-es1688= [HW,ALSA]
1424
1425 snd-es18xx= [HW,ALSA]
1426
1427 snd-es1938= [HW,ALSA]
1428
1429 snd-es1968= [HW,ALSA]
1430
1431 snd-fm801= [HW,ALSA]
1432
1433 snd-gusclassic= [HW,ALSA]
1434
1435 snd-gusextreme= [HW,ALSA]
1436
1437 snd-gusmax= [HW,ALSA]
1438
1439 snd-hdsp= [HW,ALSA]
1440
1441 snd-ice1712= [HW,ALSA]
1442
1443 snd-intel8x0= [HW,ALSA]
1444
1445 snd-interwave= [HW,ALSA]
1446
1447 snd-interwave-stb=
1448 [HW,ALSA]
1449
1450 snd-korg1212= [HW,ALSA]
1451
1452 snd-maestro3= [HW,ALSA]
1453
1454 snd-mpu401= [HW,ALSA]
1455
1456 snd-mtpav= [HW,ALSA]
1457
1458 snd-nm256= [HW,ALSA]
1459
1460 snd-opl3sa2= [HW,ALSA]
1461
1462 snd-opti92x-ad1848=
1463 [HW,ALSA]
1464
1465 snd-opti92x-cs4231=
1466 [HW,ALSA]
1467
1468 snd-opti93x= [HW,ALSA]
1469
1470 snd-pmac= [HW,ALSA]
1471
1472 snd-rme32= [HW,ALSA]
1473
1474 snd-rme96= [HW,ALSA]
1475
1476 snd-rme9652= [HW,ALSA]
1477
1478 snd-sb8= [HW,ALSA]
1479
1480 snd-sb16= [HW,ALSA]
1481
1482 snd-sbawe= [HW,ALSA]
1483
1484 snd-serial= [HW,ALSA]
1485
1486 snd-sgalaxy= [HW,ALSA]
1487
1488 snd-sonicvibes= [HW,ALSA]
1489
1490 snd-sun-amd7930=
1491 [HW,ALSA]
1492
1493 snd-sun-cs4231= [HW,ALSA]
1494
1495 snd-trident= [HW,ALSA]
1496
1497 snd-usb-audio= [HW,ALSA,USB]
1498
1499 snd-via82xx= [HW,ALSA]
1500
1501 snd-virmidi= [HW,ALSA]
1502
1503 snd-wavefront= [HW,ALSA]
1504
1505 snd-ymfpci= [HW,ALSA]
a9913044 1506
1da177e4
LT
1507 sonicvibes= [HW,OSS]
1508 Format: <reverb>
a9913044 1509
1da177e4
LT
1510 sonycd535= [HW,CD]
1511 Format: <io>[,<irq>]
1512
1513 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1514 See Documentation/sonypi.txt
1515
1516 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1517 See Documentation/specialix.txt.
1518
1519 spia_io_base= [HW,MTD]
1520 spia_fio_base=
1521 spia_pedr=
1522 spia_peddr=
1523
1524 sscape= [HW,OSS]
1525 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1526
1da177e4
LT
1527 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1528 See Documentation/scsi/st.txt.
1529
1530 st0x= [HW,SCSI]
1531 See header of drivers/scsi/seagate.c.
1532
1533 sti= [PARISC,HW]
1534 Format: <num>
1535 Set the STI (builtin display/keyboard on the HP-PARISC
1536 machines) console (graphic card) which should be used
1537 as the initial boot-console.
1538 See also comment in drivers/video/console/sticore.c.
1539
1540 sti_font= [HW]
1541 See comment in drivers/video/console/sticore.c.
1542
1543 stifb= [HW]
1544 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1545
1da177e4 1546 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1547
1da177e4
LT
1548 switches= [HW,M68k]
1549
1550 sym53c416= [HW,SCSI]
1551 See header of drivers/scsi/sym53c416.c.
1552
1553 t128= [HW,SCSI]
1554 See header of drivers/scsi/t128.c.
1555
1556 tdfx= [HW,DRM]
1557
1558 thash_entries= [KNL,NET]
1559 Set number of hash buckets for TCP connection
1560
1561 time Show timing data prefixed to each printk message line
1562
1563 tipar.timeout= [HW,PPT]
1564 Set communications timeout in tenths of a second
1565 (default 15).
1566
1567 tipar.delay= [HW,PPT]
1568 Set inter-bit delay in microseconds (default 10).
1569
1570 tmc8xx= [HW,SCSI]
1571 See header of drivers/scsi/seagate.c.
1572
1573 tmscsim= [HW,SCSI]
1574 See comment before function dc390_setup() in
1575 drivers/scsi/tmscsim.c.
1576
1577 tp720= [HW,PS2]
1578
1579 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1580 Format:
1581 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1582
1da177e4
LT
1583 tsdev.xres= [TS] Horizontal screen resolution.
1584 tsdev.yres= [TS] Vertical screen resolution.
1585
a9913044
RD
1586 turbografx.map[2|3]= [HW,JOY]
1587 TurboGraFX parallel port interface
1588 Format:
1589 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1590 See also Documentation/input/joystick-parport.txt
1591
1592 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1593 See header of drivers/scsi/u14-34f.c.
1594
1595 uart401= [HW,OSS]
1596 Format: <io>,<irq>
1597
1598 uart6850= [HW,OSS]
1599 Format: <io>,<irq>
1600
1da177e4
LT
1601 usbhid.mousepoll=
1602 [USBHID] The interval which mice are to be polled at.
a9913044 1603
1da177e4
LT
1604 video= [FB] Frame buffer configuration
1605 See Documentation/fb/modedb.txt.
1606
1607 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1608 See Documentation/i386/boot.txt and
1609 Documentation/svga.txt.
1da177e4
LT
1610 Use vga=ask for menu.
1611 This is actually a boot loader parameter; the value is
1612 passed to the kernel using a special protocol.
1613
a9913044 1614 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1615 size of <nn>. This can be used to increase the
1616 minimum size (128MB on x86). It can also be used to
1617 decrease the size and leave more room for directly
1618 mapped kernel RAM.
1619
1620 vmhalt= [KNL,S390]
1621
a9913044
RD
1622 vmpoff= [KNL,S390]
1623
1da177e4
LT
1624 waveartist= [HW,OSS]
1625 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1626
1da177e4
LT
1627 wd33c93= [HW,SCSI]
1628 See header of drivers/scsi/wd33c93.c.
1629
1630 wd7000= [HW,SCSI]
1631 See header of drivers/scsi/wd7000.c.
1632
1633 wdt= [WDT] Watchdog
1634 See Documentation/watchdog/watchdog.txt.
1635
1636 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1637 xd_geo= See header of drivers/block/xd.c.
1638
1639 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1640 Format:
1641 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 1642
a62eaf15
AK
1643 norandmaps Don't use address space randomization
1644 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1645
1da177e4 1646
a9913044 1647______________________________________________________________________
1da177e4
LT
1648Changelog:
1649
a9913044 16502000-06-?? Mr. Unknown
1da177e4 1651 The last known update (for 2.4.0) - the changelog was not kept before.
1da177e4 1652
a9913044
RD
16532002-11-24 Petr Baudis <pasky@ucw.cz>
1654 Randy Dunlap <randy.dunlap@verizon.net>
1da177e4
LT
1655 Update for 2.5.49, description for most of the options introduced,
1656 references to other documentation (C files, READMEs, ..), added S390,
1657 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1658 reformatting.
a9913044
RD
1659
16602005-10-19 Randy Dunlap <rdunlap@xenotime.net>
1661 Lots of typos, whitespace, some reformatting.
1da177e4
LT
1662
1663TODO:
1664
1665 Add documentation for ALSA options.
1666 Add more DRM drivers.