[PATCH] taskstats: free skb, avoid returns in send_cpu_listeners
[linux-2.6-block.git] / Documentation / kernel-parameters.txt
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0ee9d71f 1 Kernel Parameters
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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
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20This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
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27The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
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31
32 ACPI ACPI support is enabled.
33 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
a9913044 38 DRM Direct Rendering Management support is enabled.
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39 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
40 EFI EFI Partitioning (GPT) is enabled
41 EIDE EIDE/ATAPI support is enabled.
42 FB The frame buffer device is enabled.
43 HW Appropriate hardware is enabled.
44 IA-32 IA-32 aka i386 architecture is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
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48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LP Printer support is enabled.
52 LOOP Loopback device support is enabled.
53 M68k M68k architecture is enabled.
54 These options have more detailed description inside of
55 Documentation/m68k/kernel-options.txt.
56 MCA MCA bus support is enabled.
57 MDA MDA console support is enabled.
58 MOUSE Appropriate mouse support is enabled.
309e57df 59 MSI Message Signaled Interrupts (PCI).
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60 MTD MTD support is enabled.
61 NET Appropriate network support is enabled.
62 NUMA NUMA support is enabled.
734efb46 63 GENERIC_TIME The generic timeofday code is enabled.
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64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
a9913044 83 SWSUSP Software suspend is enabled.
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84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
95
96In addition, the following text indicates that the option:
97
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
101
102Parameters denoted with BOOT are actually interpreted by the boot
103loader, and have no meaning to the kernel directly.
104Do not modify the syntax of boot loader parameters without extreme
105need or coordination with <Documentation/i386/boot.txt>.
106
107Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108a trailing = on the name of any parameter states that that parameter will
109be entered as an environment variable, whereas its absence indicates that
110it will appear as a kernel argument readable via /proc/cmdline by programs
111running once the system is up.
112
113 53c7xx= [HW,SCSI] Amiga SCSI controllers
114 See header of drivers/scsi/53c7xx.c.
115 See also Documentation/scsi/ncr53c7xx.txt.
116
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117 acpi= [HW,ACPI] Advanced Configuration and Power Interface
118 Format: { force | off | ht | strict | noirq }
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119 force -- enable ACPI if default was off
120 off -- disable ACPI if default was on
121 noirq -- do not use ACPI for IRQ routing
122 ht -- run only enough ACPI to enable Hyper Threading
a9913044 123 strict -- Be less tolerant of platforms that are not
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124 strictly ACPI specification compliant.
125
126 See also Documentation/pm.txt, pci=noacpi
127
128 acpi_sleep= [HW,ACPI] Sleep options
129 Format: { s3_bios, s3_mode }
130 See Documentation/power/video.txt
a9913044 131
1da177e4 132 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 133 Format: { level | edge | high | low }
1da177e4 134
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135 acpi_irq_balance [HW,ACPI]
136 ACPI will balance active IRQs
137 default in APIC mode
1da177e4 138
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139 acpi_irq_nobalance [HW,ACPI]
140 ACPI will not move active IRQs (default)
141 default in PIC mode
1da177e4 142
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143 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
144 use by PCI
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145 Format: <irq>,<irq>...
146
a9913044 147 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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148 Format: <irq>,<irq>...
149
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150 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
151 Format: To spoof as Windows 98: ="Microsoft Windows"
152
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153 acpi_osi= [HW,ACPI] empty param disables _OSI
154
155 acpi_serialize [HW,ACPI] force serialization of AML methods
156
157 acpi_skip_timer_override [HW,ACPI]
158 Recognize and ignore IRQ0/pin2 Interrupt Override.
159 For broken nForce2 BIOS resulting in XT-PIC timer.
160
161 acpi_dbg_layer= [HW,ACPI]
162 Format: <int>
a9913044 163 Each bit of the <int> indicates an ACPI debug layer,
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164 1: enable, 0: disable. It is useful for boot time
165 debugging. After system has booted up, it can be set
166 via /proc/acpi/debug_layer.
167
168 acpi_dbg_level= [HW,ACPI]
169 Format: <int>
a9913044 170 Each bit of the <int> indicates an ACPI debug level,
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171 1: enable, 0: disable. It is useful for boot time
172 debugging. After system has booted up, it can be set
173 via /proc/acpi/debug_level.
174
175 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
176
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177 acpi_generic_hotkey [HW,ACPI]
178 Allow consolidated generic hotkey driver to
a9913044 179 override platform specific driver.
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180 See also Documentation/acpi-hotkey.txt.
181
5d0cf410 182 acpi_pm_good [IA-32,X86-64]
183 Override the pmtimer bug detection: force the kernel
184 to assume that this machine's pmtimer latches its value
185 and always returns good values.
186
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187 enable_timer_pin_1 [i386,x86-64]
188 Enable PIN 1 of APIC timer
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189 Can be useful to work around chipset bugs
190 (in particular on some ATI chipsets).
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191 The kernel tries to set a reasonable default.
192
193 disable_timer_pin_1 [i386,x86-64]
194 Disable PIN 1 of APIC timer
195 Can be useful to work around chipset bugs.
196
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197 ad1816= [HW,OSS]
198 Format: <io>,<irq>,<dma>,<dma2>
199 See also Documentation/sound/oss/AD1816.
200
201 ad1848= [HW,OSS]
202 Format: <io>,<irq>,<dma>,<dma2>,<type>
203
204 adlib= [HW,OSS]
205 Format: <io>
a9913044 206
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207 advansys= [HW,SCSI]
208 See header of drivers/scsi/advansys.c.
209
210 advwdt= [HW,WDT] Advantech WDT
211 Format: <iostart>,<iostop>
212
213 aedsp16= [HW,OSS] Audio Excel DSP 16
214 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
215 See also header of sound/oss/aedsp16.c.
a9913044 216
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217 aha152x= [HW,SCSI]
218 See Documentation/scsi/aha152x.txt.
219
220 aha1542= [HW,SCSI]
221 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
222
223 aic7xxx= [HW,SCSI]
224 See Documentation/scsi/aic7xxx.txt.
225
226 aic79xx= [HW,SCSI]
227 See Documentation/scsi/aic79xx.txt.
228
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229 amijoy.map= [HW,JOY] Amiga joystick support
230 Map of devices attached to JOY0DAT and JOY1DAT
231 Format: <a>,<b>
232 See also Documentation/kernel/input/joystick.txt
233
234 analog.map= [HW,JOY] Analog joystick and gamepad support
235 Specifies type or capabilities of an analog joystick
236 connected to one of 16 gameports
237 Format: <type1>,<type2>,..<type16>
238
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239 apc= [HW,SPARC]
240 Power management functions (SPARCstation-4/5 + deriv.)
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241 Format: noidle
242 Disable APC CPU standby support. SPARCstation-Fox does
243 not play well with APC CPU idle - disable it if you have
244 APC and your system crashes randomly.
245
a9913044 246 apic= [APIC,i386] Change the output verbosity whilst booting
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247 Format: { quiet (default) | verbose | debug }
248 Change the amount of debugging information output
249 when initialising the APIC and IO-APIC components.
a9913044 250
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251 apm= [APM] Advanced Power Management
252 See header of arch/i386/kernel/apm.c.
253
254 applicom= [HW]
255 Format: <mem>,<irq>
a9913044 256
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257 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
258 Format: <io>,<irq>,<nodeID>
259
260 ataflop= [HW,M68k]
261
262 atarimouse= [HW,MOUSE] Atari Mouse
263
264 atascsi= [HW,SCSI] Atari SCSI
265
266 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
267 EzKey and similar keyboards
268
269 atkbd.reset= [HW] Reset keyboard during initialization
270
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271 atkbd.set= [HW] Select keyboard code set
272 Format: <int> (2 = AT (default), 3 = PS/2)
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273
274 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
275 keyboards
276
277 atkbd.softraw= [HW] Choose between synthetic and real raw mode
278 Format: <bool> (0 = real, 1 = synthetic (default))
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279
280 atkbd.softrepeat= [HW]
281 Use software keyboard repeat
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282
283 autotest [IA64]
284
285 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
286 Format: <io>,<memsize>,<isapnp>
a9913044 287
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288 aztcd= [HW,CD] Aztech CD268 CDROM driver
289 Format: <io>,0x79 (?)
290
291 baycom_epp= [HW,AX25]
292 Format: <io>,<mode>
a9913044 293
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294 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
295 Format: <io>,<mode>
296 See header of drivers/net/hamradio/baycom_par.c.
297
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298 baycom_ser_fdx= [HW,AX25]
299 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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300 Format: <io>,<irq>,<mode>[,<baud>]
301 See header of drivers/net/hamradio/baycom_ser_fdx.c.
302
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303 baycom_ser_hdx= [HW,AX25]
304 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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305 Format: <io>,<irq>,<mode>
306 See header of drivers/net/hamradio/baycom_ser_hdx.c.
307
308 blkmtd_device= [HW,MTD]
309 blkmtd_erasesz=
310 blkmtd_ro=
311 blkmtd_bs=
312 blkmtd_count=
313
314 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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315 bttv.radio= Most important insmod options are available as
316 kernel args too.
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317 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
318 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
319
320 BusLogic= [HW,SCSI]
321 See drivers/scsi/BusLogic.c, comment before function
322 BusLogic_ParseDriverOptions().
323
324 c101= [NET] Moxa C101 synchronous serial card
325
326 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
327 Sometimes CPU hardware bugs make them report the cache
328 size incorrectly. The kernel will attempt work arounds
329 to fix known problems, but for some CPUs it is not
330 possible to determine what the correct size should be.
331 This option provides an override for these situations.
332
333 cdu31a= [HW,CD]
334 Format: <io>,<irq>[,PAS]
335 See header of drivers/cdrom/cdu31a.c.
336
337 chandev= [HW,NET] Generic channel device initialisation
338
339 checkreqprot [SELINUX] Set initial checkreqprot flag value.
340 Format: { "0" | "1" }
341 See security/selinux/Kconfig help text.
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342 0 -- check protection applied by kernel (includes
343 any implied execute protection).
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344 1 -- check protection requested by application.
345 Default value is set via a kernel config option.
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346 Value can be changed at runtime via
347 /selinux/checkreqprot.
348
734efb46 349 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
350 [Deprecated]
351 Forces specified clocksource (if avaliable) to be used
352 when calculating gettimeofday(). If specified
353 clocksource is not avalible, it defaults to PIT.
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354 Format: { pit | tsc | cyclone | pmtmr }
355
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356 disable_8254_timer
357 enable_8254_timer
358 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
359 over the 8254 in addition to over the IO-APIC. The
360 kernel tries to set a sensible default.
361
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362 hpet= [IA-32,HPET] option to disable HPET and use PIT.
363 Format: disable
364
365 cm206= [HW,CD]
366 Format: { auto | [<io>,][<irq>] }
367
368 com20020= [HW,NET] ARCnet - COM20020 chipset
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369 Format:
370 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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371
372 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
373 Format: <io>[,<irq>]
374
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375 com90xx= [HW,NET]
376 ARCnet - COM90xx chipset (memory-mapped buffers)
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377 Format: <io>[,<irq>[,<memstart>]]
378
379 condev= [HW,S390] console device
380 conmode=
a9913044 381
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382 console= [KNL] Output console device and options.
383
384 tty<n> Use the virtual console device <n>.
385
386 ttyS<n>[,options]
f1a1c2dc 387 ttyUSB0[,options]
1da177e4 388 Use the specified serial port. The options are of
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389 the form "bbbbpnf", where "bbbb" is the baud rate,
390 "p" is parity ("n", "o", or "e"), "n" is number of
391 bits, and "f" is flow control ("r" for RTS or
392 omit it). Default is "9600n8".
393
394 See Documentation/serial-console.txt for more
395 information. See
396 Documentation/networking/netconsole.txt for an
397 alternative.
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398
399 uart,io,<addr>[,options]
400 uart,mmio,<addr>[,options]
401 Start an early, polled-mode console on the 8250/16550
402 UART at the specified I/O port or MMIO address,
403 switching to the matching ttyS device later. The
404 options are the same as for ttyS, above.
405
406 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
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407 Format:
408 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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409
410 cpia_pp= [HW,PPT]
411 Format: { parport<nr> | auto | none }
412
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413 crashkernel=nn[KMG]@ss[KMG]
414 [KNL] Reserve a chunk of physical memory to
415 hold a kernel to switch to with kexec on panic.
416
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417 cs4232= [HW,OSS]
418 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
419
420 cs89x0_dma= [HW,NET]
421 Format: <dma>
422
423 cs89x0_media= [HW,NET]
424 Format: { rj45 | aui | bnc }
a9913044 425
1da177e4 426 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
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427
428 dasd= [HW,NET]
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429 See header of drivers/s390/block/dasd_devmap.c.
430
431 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
432 (one device per port)
433 Format: <port#>,<type>
434 See also Documentation/input/joystick-parport.txt
435
436 debug [KNL] Enable kernel debugging (events log level).
437
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438 debug_locks_verbose=
439 [KNL] verbose self-tests
440 Format=<0|1>
441 Print debugging info while doing the locking API
442 self-tests.
443 We default to 0 (no extra messages), setting it to
444 1 will print _a lot_ more information - normally
445 only useful to kernel developers.
446
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447 decnet= [HW,NET]
448 Format: <area>[,<node>]
449 See also Documentation/networking/decnet.txt.
450
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451 delayacct [KNL] Enable per-task delay accounting
452
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453 dhash_entries= [KNL]
454 Set number of hash buckets for dentry cache.
a9913044 455
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456 digi= [HW,SERIAL]
457 IO parameters + enable/disable command.
458
459 digiepca= [HW,SERIAL]
460 See drivers/char/README.epca and
461 Documentation/digiepca.txt.
462
463 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
464 support available.
465 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
466
467 dmasound= [HW,OSS] Sound subsystem buffers
468
469 dscc4.setup= [NET]
470
471 dtc3181e= [HW,SCSI]
472
a9913044 473 earlyprintk= [IA-32,X86-64]
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474 earlyprintk=vga
475 earlyprintk=serial[,ttySn[,baudrate]]
476
a9913044 477 Append ",keep" to not disable it when the real console
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478 takes over.
479
480 Only vga or serial at a time, not both.
481
482 Currently only ttyS0 and ttyS1 are supported.
483
484 Interaction with the standard serial driver is not
485 very good.
486
487 The VGA output is eventually overwritten by the real
488 console.
489
490 eata= [HW,SCSI]
491
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492 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
493 Format: <int>
494 0: polling mode
495 non-0: interrupt mode (default)
496
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497 eda= [HW,PS2]
498
499 edb= [HW,PS2]
500
501 edd= [EDD]
502 Format: {"of[f]" | "sk[ipmbr]"}
503 See comment in arch/i386/boot/edd.S
504
a9913044 505 eicon= [HW,ISDN]
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506 Format: <id>,<membase>,<irq>
507
508 eisa_irq_edge= [PARISC,HW]
509 See header of drivers/parisc/eisa.c.
510
511 elanfreq= [IA-32]
512 See comment before function elanfreq_setup() in
513 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
514
515 elevator= [IOSCHED]
16ab3adf 516 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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517 See Documentation/block/as-iosched.txt and
518 Documentation/block/deadline-iosched.txt for details.
519
aac04b32 520 elfcorehdr= [IA-32, X86_64]
a9913044 521 Specifies physical address of start of kernel core
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522 image elf header. Generally kexec loader will
523 pass this option to capture kernel.
524 See Documentation/kdump/kdump.txt for details.
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525
526 enforcing [SELINUX] Set initial enforcing status.
527 Format: {"0" | "1"}
528 See security/selinux/Kconfig help text.
529 0 -- permissive (log only, no denials).
530 1 -- enforcing (deny and log).
531 Default value is 0.
532 Value can be changed at runtime via /selinux/enforce.
533
534 es1370= [HW,OSS]
535 Format: <lineout>[,<micbias>]
536 See also header of sound/oss/es1370.c.
537
538 es1371= [HW,OSS]
539 Format: <spdif>,[<nomix>,[<amplifier>]]
540 See also header of sound/oss/es1371.c.
a9913044 541
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542 ether= [HW,NET] Ethernet cards parameters
543 This option is obsoleted by the "netdev=" option, which
544 has equivalent usage. See its documentation for details.
545
546 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
547 Format: <io>[,<irq>]
548
549 fd_mcs= [HW,SCSI]
550 See header of drivers/scsi/fd_mcs.c.
551
552 fdomain= [HW,SCSI]
553 See header of drivers/scsi/fdomain.c.
554
555 floppy= [HW]
556 See Documentation/floppy.txt.
557
558 ftape= [HW] Floppy Tape subsystem debugging options.
559 See Documentation/ftape.txt.
560
561 gamecon.map[2|3]=
562 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
563 support via parallel port (up to 5 devices per port)
564 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
565 See also Documentation/input/joystick-parport.txt
566
567 gamma= [HW,DRM]
568
569 gdth= [HW,SCSI]
570 See header of drivers/scsi/gdth.c.
571
572 gpt [EFI] Forces disk with valid GPT signature but
573 invalid Protective MBR to be treated as GPT.
574
575 gscd= [HW,CD]
576 Format: <io>
577
578 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
579
580 gus= [HW,OSS]
581 Format: <io>,<irq>,<dma>,<dma16>
a9913044 582
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583 gvp11= [HW,SCSI]
584
585 hashdist= [KNL,NUMA] Large hashes allocated during boot
586 are distributed across NUMA nodes. Defaults on
587 for IA-64, off otherwise.
a9913044 588 Format: 0 | 1 (for off | on)
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589
590 hcl= [IA-64] SGI's Hardware Graph compatibility layer
591
592 hd= [EIDE] (E)IDE hard drive subsystem geometry
593 Format: <cyl>,<head>,<sect>
594
595 hd?= [HW] (E)IDE subsystem
596 hd?lun= See Documentation/ide.txt.
597
598 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
599 size of <nn>. This works even on boxes that have no
600 highmem otherwise. This also works to reduce highmem
601 size on bigger boxes.
602
603 hisax= [HW,ISDN]
604 See Documentation/isdn/README.HiSax.
605
606 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
607
608 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
609
610 i8042.direct [HW] Put keyboard port into non-translated mode
611 i8042.dumbkbd [HW] Pretend that controlled can only read data from
612 keyboard and can not control its state
613 (Don't attempt to blink the leds)
614 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 615 i8042.nokbd [HW] Don't check/create keyboard port
1da177e4
LT
616 i8042.nomux [HW] Don't check presence of an active multiplexing
617 controller
618 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
619 controllers
620 i8042.panicblink=
621 [HW] Frequency with which keyboard LEDs should blink
622 when kernel panics (default is 0.5 sec)
623 i8042.reset [HW] Reset the controller during init and cleanup
624 i8042.unlock [HW] Unlock (ignore) the keylock
625
626 i810= [HW,DRM]
627
e70c9d5e
DT
628 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
629 indicates that the driver is running on unsupported
630 hardware.
1da177e4
LT
631 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
632 does not match list of supported models.
633 i8k.power_status
634 [HW] Report power status in /proc/i8k
635 (disabled by default)
636 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
637 capability is set.
638
639 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
640 See Documentation/mca.txt.
641
642 icn= [HW,ISDN]
643 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
644
645 ide= [HW] (E)IDE subsystem
646 Format: ide=nodma or ide=doubler or ide=reverse
647 See Documentation/ide.txt.
648
649 ide?= [HW] (E)IDE subsystem
650 Format: ide?=noprobe or chipset specific parameters.
651 See Documentation/ide.txt.
a9913044 652
1da177e4
LT
653 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
654 See Documentation/ide.txt.
655
656 idle= [HW]
657 Format: idle=poll or idle=halt
a9913044 658
1da177e4
LT
659 ihash_entries= [KNL]
660 Set number of hash buckets for inode cache.
661
662 in2000= [HW,SCSI]
663 See header of drivers/scsi/in2000.c.
664
665 init= [KNL]
666 Format: <full_path>
667 Run specified binary instead of /sbin/init as init
668 process.
669
670 initcall_debug [KNL] Trace initcalls as they are executed. Useful
671 for working out where the kernel is dying during
672 startup.
673
674 initrd= [BOOT] Specify the location of the initial ramdisk
675
676 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
677 Format: <irq>
678
2bd0fa3b
JB
679 combined_mode= [HW] control which driver uses IDE ports in combined
680 mode: legacy IDE driver, libata, or both
681 (in the libata case, libata.atapi_enabled=1 may be
682 useful as well). Note that using the ide or libata
683 options may affect your device naming (e.g. by
684 changing hdc to sdb).
685 Format: combined (default), ide, or libata
686
1da177e4
LT
687 inttest= [IA64]
688
689 io7= [HW] IO7 for Marvel based alpha systems
690 See comment before marvel_specify_io7 in
691 arch/alpha/kernel/core_marvel.c.
692
693 ip= [IP_PNP]
694 See Documentation/nfsroot.txt.
695
696 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
697 See comment before ip2_setup() in drivers/char/ip2.c.
698
699 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
700 See header of drivers/scsi/ips.c.
701
200803df
AC
702 irqfixup [HW]
703 When an interrupt is not handled search all handlers
704 for it. Intended to get systems with badly broken
705 firmware running.
706
707 irqpoll [HW]
708 When an interrupt is not handled search all handlers
709 for it. Also check all handlers each timer
710 interrupt. Intended to get systems with badly broken
711 firmware running.
712
1da177e4 713 isapnp= [ISAPNP]
a9913044 714 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
715
716 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
717 Format: <cpu number>,...,<cpu number>
718 This option can be used to specify one or more CPUs
719 to isolate from the general SMP balancing and scheduling
720 algorithms. The only way to move a process onto or off
721 an "isolated" CPU is via the CPU affinity syscalls.
722 <cpu number> begins at 0 and the maximum value is
723 "number of CPUs in system - 1".
724
725 This option is the preferred way to isolate CPUs. The
a9913044
RD
726 alternative -- manually setting the CPU mask of all
727 tasks in the system -- can cause problems and
728 suboptimal load balancer performance.
1da177e4
LT
729
730 isp16= [HW,CD]
731 Format: <io>,<irq>,<dma>,<setup>
732
a9913044 733 iucv= [HW,NET]
1da177e4
LT
734
735 js= [HW,JOY] Analog joystick
736 See Documentation/input/joystick.txt.
737
738 keepinitrd [HW,ARM]
739
a9913044 740 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
741 in oops dumps.
742
743 l2cr= [PPC]
744
a9913044
RD
745 lapic [IA-32,APIC] Enable the local APIC even if BIOS
746 disabled it.
1da177e4
LT
747
748 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
749 Format: addr:<io>,irq:<irq>
750
a9913044
RD
751 llsc*= [IA64] See function print_params() in
752 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
753
754 load_ramdisk= [RAM] List of ramdisks to load from floppy
755 See Documentation/ramdisk.txt.
756
a6b25b67
RD
757 lockd.nlm_grace_period=P [NFS] Assign grace period.
758 Format: <integer>
1da177e4 759
a6b25b67
RD
760 lockd.nlm_tcpport=N [NFS] Assign TCP port.
761 Format: <integer>
762
763 lockd.nlm_timeout=T [NFS] Assign timeout value.
764 Format: <integer>
765
766 lockd.nlm_udpport=M [NFS] Assign UDP port.
767 Format: <integer>
1da177e4
LT
768
769 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
770 Format: <irq>
771
772 loglevel= All Kernel Messages with a loglevel smaller than the
773 console loglevel will be printed to the console. It can
774 also be changed with klogd or other programs. The
775 loglevels are defined as follows:
776
777 0 (KERN_EMERG) system is unusable
778 1 (KERN_ALERT) action must be taken immediately
779 2 (KERN_CRIT) critical conditions
780 3 (KERN_ERR) error conditions
781 4 (KERN_WARNING) warning conditions
782 5 (KERN_NOTICE) normal but significant condition
783 6 (KERN_INFO) informational
784 7 (KERN_DEBUG) debug-level messages
785
786 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
787 Format: { n | nk | nM }
788 n must be a power of two. The default size
789 is set in the kernel config file.
1da177e4
LT
790
791 lp=0 [LP] Specify parallel ports to use, e.g,
792 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
793 lp=reset first parallel port). 'lp=0' disables the
794 lp=auto printer driver. 'lp=reset' (which can be
795 specified in addition to the ports) causes
796 attached printers to be reset. Using
797 lp=port1,port2,... specifies the parallel ports
798 to associate lp devices with, starting with
799 lp0. A port specification may be 'none' to skip
800 that lp device, or a parport name such as
801 'parport0'. Specifying 'lp=auto' instead of a
802 port specification list means that device IDs
803 from each port should be examined, to see if
804 an IEEE 1284-compliant printer is attached; if
805 so, the driver will manage that printer.
806 See also header of drivers/char/lp.c.
807
808 lpj=n [KNL]
809 Sets loops_per_jiffy to given constant, thus avoiding
810 time-consuming boot-time autodetection (up to 250 ms per
811 CPU). 0 enables autodetection (default). To determine
812 the correct value for your kernel, boot with normal
813 autodetection and see what value is printed. Note that
814 on SMP systems the preset will be applied to all CPUs,
815 which is likely to cause problems if your CPUs need
816 significantly divergent settings. An incorrect value
817 will cause delays in the kernel to be wrong, leading to
818 unpredictable I/O errors and other breakage. Although
819 unlikely, in the extreme case this might damage your
820 hardware.
821
822 ltpc= [NET]
823 Format: <io>,<irq>,<dma>
824
a9913044
RD
825 mac5380= [HW,SCSI] Format:
826 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 827
a9913044
RD
828 mac53c9x= [HW,SCSI] Format:
829 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 830
a9913044
RD
831 machvec= [IA64] Force the use of a particular machine-vector
832 (machvec) in a generic kernel.
833 Example: machvec=hpzx1_swiotlb
1da177e4 834
a9913044
RD
835 mad16= [HW,OSS] Format:
836 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
837
838 maui= [HW,OSS]
839 Format: <io>,<irq>
a9913044
RD
840
841 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
842 be mounted
843 Format: <1-256>
844
845 maxcpus= [SMP] Maximum number of processors that an SMP kernel
846 should make use of
847
2b2c3750
BP
848 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
849 equal to this physical address is ignored.
850
a9913044 851 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
852 Should be between 1 and 2^32-1.
853
854 max_report_luns=
a9913044 855 [SCSI] Maximum number of LUNs received.
1da177e4
LT
856 Should be between 1 and 16384.
857
858 mca-pentium [BUGS=IA-32]
859
860 mcatest= [IA-64]
861
862 mcd= [HW,CD]
863 Format: <port>,<irq>,<mitsumi_bug_93_wait>
864
865 mcdx= [HW,CD]
866
867 mce [IA-32] Machine Check Exception
868
869 md= [HW] RAID subsystems devices and level
870 See Documentation/md.txt.
a9913044 871
1da177e4
LT
872 mdacon= [MDA]
873 Format: <first>,<last>
874 Specifies range of consoles to be captured by the MDA.
a9913044 875
1da177e4
LT
876 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
877 Amount of memory to be used when the kernel is not able
878 to see the whole system memory or for test.
879 [IA-32] Use together with memmap= to avoid physical
880 address space collisions. Without memmap= PCI devices
881 could be placed at addresses belonging to unused RAM.
882
883 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
884 memory.
885
69cda7b1 886 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
887 E820 memory map, as specified by the user.
888 Such memmap=exactmap lines can be constructed based on
889 BIOS output or other requirements. See the memmap=nn@ss
890 option description.
891
892 memmap=nn[KMG]@ss[KMG]
893 [KNL] Force usage of a specific region of memory
894 Region of memory to be used, from ss to ss+nn.
895
896 memmap=nn[KMG]#ss[KMG]
897 [KNL,ACPI] Mark specific memory as ACPI data.
898 Region of memory to be used, from ss to ss+nn.
899
900 memmap=nn[KMG]$ss[KMG]
901 [KNL,ACPI] Mark specific memory as reserved.
902 Region of memory to be used, from ss to ss+nn.
903
904 meye.*= [HW] Set MotionEye Camera parameters
905 See Documentation/video4linux/meye.txt.
906
907 mga= [HW,DRM]
908
198e2f18 909 migration_cost=
910 [KNL,SMP] debug: override scheduler migration costs
911 Format: <level-1-usecs>,<level-2-usecs>,...
912 This debugging option can be used to override the
913 default scheduler migration cost matrix. The numbers
914 are indexed by 'CPU domain distance'.
915 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
916 box will set up an intra-core migration cost of
917 1 msec, an inter-core migration cost of 2 msecs,
918 and an inter-node migration cost of 3 msecs.
919
920 WARNING: using the wrong values here can break
921 scheduler performance, so it's only for scheduler
922 development purposes, not production environments.
923
924 migration_debug=
925 [KNL,SMP] migration cost auto-detect verbosity
926 Format=<0|1|2>
927 If a system's migration matrix reported at bootup
928 seems erroneous then this option can be used to
929 increase verbosity of the detection process.
930 We default to 0 (no extra messages), 1 will print
931 some more information, and 2 will be really
932 verbose (probably only useful if you also have a
933 serial console attached to the system).
934
935 migration_factor=
936 [KNL,SMP] multiply/divide migration costs by a factor
937 Format=<percent>
938 This debug option can be used to proportionally
939 increase or decrease the auto-detected migration
940 costs for all entries of the migration matrix.
941 E.g. migration_factor=150 will increase migration
942 costs by 50%. (and thus the scheduler will be less
943 eager migrating cache-hot tasks)
944 migration_factor=80 will decrease migration costs
945 by 20%. (thus the scheduler will be more eager to
946 migrate tasks)
947
948 WARNING: using the wrong values here can break
949 scheduler performance, so it's only for scheduler
950 development purposes, not production environments.
951
1da177e4
LT
952 mousedev.tap_time=
953 [MOUSE] Maximum time between finger touching and
954 leaving touchpad surface for touch to be considered
955 a tap and be reported as a left button click (for
956 touchpads working in absolute mode only).
957 Format: <msecs>
958 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
959 reporting absolute coordinates, such as tablets
960 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
961 reporting absolute coordinates, such as tablets
962
963 mpu401= [HW,OSS]
964 Format: <io>,<irq>
965
966 MTD_Partition= [MTD]
967 Format: <name>,<region-number>,<size>,<offset>
968
a9913044
RD
969 MTD_Region= [MTD] Format:
970 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
971
972 mtdparts= [MTD]
973 See drivers/mtd/cmdline.c.
974
975 mtouchusb.raw_coordinates=
a9913044
RD
976 [HW] Make the MicroTouch USB driver use raw coordinates
977 ('y', default) or cooked coordinates ('n')
1da177e4
LT
978
979 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
980
981 NCR_D700= [HW,SCSI]
982 See header of drivers/scsi/NCR_D700.c.
983
984 ncr5380= [HW,SCSI]
985
986 ncr53c400= [HW,SCSI]
987
988 ncr53c400a= [HW,SCSI]
989
990 ncr53c406a= [HW,SCSI]
991
992 ncr53c8xx= [HW,SCSI]
993
994 netdev= [NET] Network devices parameters
995 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
996 Note that mem_start is often overloaded to mean
997 something different and driver-specific.
a9913044
RD
998 This usage is only documented in each driver source
999 file if at all.
1000
1da177e4
LT
1001 nfsaddrs= [NFS]
1002 See Documentation/nfsroot.txt.
1003
1004 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1005 See Documentation/nfsroot.txt.
1006
a72b4422
TM
1007 nfs.callback_tcpport=
1008 [NFS] set the TCP port on which the NFSv4 callback
1009 channel should listen.
1010
58df095b
TM
1011 nfs.idmap_cache_timeout=
1012 [NFS] set the maximum lifetime for idmapper cache
1013 entries.
1014
1da177e4
LT
1015 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1016
1017 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1018 emulation library even if a 387 maths coprocessor
1019 is present.
1020
a9913044
RD
1021 noalign [KNL,ARM]
1022
1da177e4
LT
1023 noapic [SMP,APIC] Tells the kernel to not make use of any
1024 IOAPICs that may be present in the system.
1025
1026 noasync [HW,M68K] Disables async and sync negotiation for
1027 all devices.
1028
1029 nobats [PPC] Do not use BATs for mapping kernel lowmem
1030 on "Classic" PPC cores.
1031
1032 nocache [ARM]
a9913044 1033
1da177e4
LT
1034 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1035
1036 noexec [IA-64]
1037
a9913044 1038 noexec [IA-32,X86-64]
1da177e4
LT
1039 noexec=on: enable non-executable mappings (default)
1040 noexec=off: disable nn-executable mappings
1041
4f886511
CE
1042 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1043 register save and restore. The kernel will only save
1044 legacy floating-point registers on task switch.
1da177e4
LT
1045
1046 nohlt [BUGS=ARM]
a9913044 1047
1da177e4
LT
1048 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1049 instruction doesn't work correctly and not to
1050 use it.
1051
1052 nohalt [IA-64] Tells the kernel not to use the power saving
1053 function PAL_HALT_LIGHT when idle. This increases
1054 power-consumption. On the positive side, it reduces
1055 interrupt wake-up latency, which may improve performance
1056 in certain environments such as networked servers or
1057 real-time systems.
1058
1059 noirqdebug [IA-32] Disables the code which attempts to detect and
1060 disable unhandled interrupt sources.
1061
1062 noisapnp [ISAPNP] Disables ISA PnP code.
1063
1064 noinitrd [RAM] Tells the kernel not to load any configured
1065 initial RAM disk.
1066
1067 nointroute [IA-64]
1068
1069 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1070
1071 noltlbs [PPC] Do not use large page/tlb entries for kernel
1072 lowmem mapping on PPC40x.
1073
312f1f01
H
1074 nomca [IA-64] Disable machine check abort handling
1075
abe37e5a
H
1076 nomce [IA-32] Machine Check Exception
1077
1da177e4
LT
1078 noresidual [PPC] Don't use residual data on PReP machines.
1079
a9913044
RD
1080 noresume [SWSUSP] Disables resume and restores original swap
1081 space.
1082
1da177e4
LT
1083 no-scroll [VGA] Disables scrollback.
1084 This is required for the Braillex ib80-piezo Braille
1085 reader made by F.H. Papenmeier (Germany).
1086
1087 nosbagart [IA-64]
1088
4f886511
CE
1089 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1090
1da177e4
LT
1091 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1092
1093 nosync [HW,M68K] Disables sync negotiation for all devices.
1094
1095 notsc [BUGS=IA-32] Disable Time Stamp Counter
1096
1097 nousb [USB] Disable the USB subsystem
1098
1099 nowb [ARM]
a9913044 1100
a61c2d78
DJ
1101 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1102
1da177e4
LT
1103 opl3= [HW,OSS]
1104 Format: <io>
1105
1106 opl3sa= [HW,OSS]
1107 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1108
a9913044
RD
1109 opl3sa2= [HW,OSS] Format:
1110 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1111
1da177e4
LT
1112 oprofile.timer= [HW]
1113 Use timer interrupt instead of performance counters
1114
1115 optcd= [HW,CD]
1116 Format: <io>
1117
1118 osst= [HW,SCSI] SCSI Tape Driver
1119 Format: <buffer_size>,<write_threshold>
1120 See also Documentation/scsi/st.txt.
1121
1122 panic= [KNL] Kernel behaviour on panic
1123 Format: <timeout>
1124
1125 parkbd.port= [HW] Parallel port number the keyboard adapter is
1126 connected to, default is 0.
1127 Format: <parport#>
1128 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1129 0 for XT, 1 for AT (default is AT).
a9913044
RD
1130 Format: <mode>
1131
1132 parport= [HW,PPT] Specify parallel ports. 0 disables.
1133 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1134 Use 'auto' to force the driver to use any
1135 IRQ/DMA settings detected (the default is to
1136 ignore detected IRQ/DMA settings because of
1137 possible conflicts). You can specify the base
1138 address, IRQ, and DMA settings; IRQ and DMA
1139 should be numbers, or 'auto' (for using detected
1140 settings on that particular port), or 'nofifo'
1141 (to avoid using a FIFO even if it is detected).
1142 Parallel ports are assigned in the order they
1143 are specified on the command line, starting
1144 with parport0.
1145
1146 parport_init_mode= [HW,PPT]
1147 Configure VIA parallel port to operate in
1148 a specific mode. This is necessary on Pegasos
1149 computer where firmware has no options for setting
1150 up parallel port mode and sets it to spp.
1151 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1152 Format: [spp|ps2|epp|ecp|ecpepp]
1153
a9913044
RD
1154 pas2= [HW,OSS] Format:
1155 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1156
1da177e4
LT
1157 pas16= [HW,SCSI]
1158 See header of drivers/scsi/pas16.c.
1159
dd287796
AM
1160 pause_on_oops=
1161 Halt all CPUs after the first oops has been printed for
1162 the specified number of seconds. This is to be used if
1163 your oopses keep scrolling off the screen.
1164
1da177e4
LT
1165 pcbit= [HW,ISDN]
1166
1167 pcd. [PARIDE]
1168 See header of drivers/block/paride/pcd.c.
1169 See also Documentation/paride.txt.
1170
a9913044
RD
1171 pci=option[,option...] [PCI] various PCI subsystem options:
1172 off [IA-32] don't probe for the PCI bus
1173 bios [IA-32] force use of PCI BIOS, don't access
1174 the hardware directly. Use this if your machine
1175 has a non-standard PCI host bridge.
1176 nobios [IA-32] disallow use of PCI BIOS, only direct
1177 hardware access methods are allowed. Use this
1178 if you experience crashes upon bootup and you
1179 suspect they are caused by the BIOS.
1180 conf1 [IA-32] Force use of PCI Configuration
1181 Mechanism 1.
1182 conf2 [IA-32] Force use of PCI Configuration
1183 Mechanism 2.
61be6d66
BH
1184 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1185 Configuration
309e57df
MW
1186 nomsi [MSI] If the PCI_MSI kernel config parameter is
1187 enabled, this kernel boot option can be used to
1188 disable the use of MSI interrupts system-wide.
a9913044
RD
1189 nosort [IA-32] Don't sort PCI devices according to
1190 order given by the PCI BIOS. This sorting is
1191 done to get a device order compatible with
1192 older kernels.
1193 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1194 routing table. These calls are known to be buggy
1195 on several machines and they hang the machine
1196 when used, but on other computers it's the only
1197 way to get the interrupt routing table. Try
1198 this option if the kernel is unable to allocate
1199 IRQs or discover secondary PCI buses on your
1200 motherboard.
1201 rom [IA-32] Assign address space to expansion ROMs.
1202 Use with caution as certain devices share
1203 address decoders between ROMs and other
1204 resources.
1205 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1206 assigned automatically to PCI devices. You can
1207 make the kernel exclude IRQs of your ISA cards
1208 this way.
120bb424 1209 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1210 of the PIRQ table (normally generated
1211 by the BIOS) if it is outside the
1212 F0000h-100000h range.
1213 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1214 useful if the kernel is unable to find your
1215 secondary buses and you want to tell it
1216 explicitly which ones they are.
1217 assign-busses [IA-32] Always assign all PCI bus
1218 numbers ourselves, overriding
1219 whatever the firmware may have done.
1220 usepirqmask [IA-32] Honor the possible IRQ mask stored
1221 in the BIOS $PIR table. This is needed on
1222 some systems with broken BIOSes, notably
1223 some HP Pavilion N5400 and Omnibook XE3
1224 notebooks. This will have no effect if ACPI
1225 IRQ routing is enabled.
1226 noacpi [IA-32] Do not use ACPI for IRQ routing
1227 or for PCI scanning.
1228 routeirq Do IRQ routing for all PCI devices.
1229 This is normally done in pci_enable_device(),
1230 so this option is a temporary workaround
1231 for broken drivers that don't call it.
1232 firmware [ARM] Do not re-enumerate the bus but instead
1233 just use the configuration from the
1234 bootloader. This is currently used on
1235 IXP2000 systems where the bus has to be
1236 configured a certain way for adjunct CPUs.
1da177e4
LT
1237
1238 pcmv= [HW,PCMCIA] BadgePAD 4
1239
1240 pd. [PARIDE]
1241 See Documentation/paride.txt.
1242
1243 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1244 boot time.
1245 Format: { 0 | 1 }
1246 See arch/parisc/kernel/pdc_chassis.c
1247
1248 pf. [PARIDE]
1249 See Documentation/paride.txt.
1250
1251 pg. [PARIDE]
1252 See Documentation/paride.txt.
1253
1254 pirq= [SMP,APIC] Manual mp-table setup
1255 See Documentation/i386/IO-APIC.txt.
1256
1257 plip= [PPT,NET] Parallel port network link
1258 Format: { parport<nr> | timid | 0 }
1259 See also Documentation/parport.txt.
1260
1261 pnpacpi= [ACPI]
1262 { off }
1263
1264 pnpbios= [ISAPNP]
1265 { on | off | curr | res | no-curr | no-res }
1266
1267 pnp_reserve_irq=
1268 [ISAPNP] Exclude IRQs for the autoconfiguration
1269
1270 pnp_reserve_dma=
1271 [ISAPNP] Exclude DMAs for the autoconfiguration
1272
1273 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1274 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1275
1276 pnp_reserve_mem=
a9913044
RD
1277 [ISAPNP] Exclude memory regions for the
1278 autoconfiguration.
1da177e4
LT
1279 Ranges are in pairs (memory base and size).
1280
1281 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1282 Format: [schedule,]<number>
1283 Param: "schedule" - profile schedule points.
1284 Param: <number> - step/bucket size as a power of 2 for
1285 statistical time based profiling.
1da177e4 1286
a9913044 1287 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1288 Limit processor to maximum C-state
1289 max_cstate=9 overrides any DMI blacklist limit.
1290
41c0d868
LB
1291 processor.nocst [HW,ACPI]
1292 Ignore the _CST method to determine C-states,
1293 instead using the legacy FADT method
1294
1da177e4
LT
1295 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1296 before loading.
1297 See Documentation/ramdisk.txt.
1298
a9913044
RD
1299 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1300 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1301 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1302 per second.
a9913044
RD
1303 psmouse.resetafter= [HW,MOUSE]
1304 Try to reset the device after so many bad packets
1da177e4
LT
1305 (0 = never).
1306 psmouse.resolution=
1307 [HW,MOUSE] Set desired mouse resolution, in dpi.
1308 psmouse.smartscroll=
a9913044 1309 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1310 0 = disabled, 1 = enabled (default).
1311
1312 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1313 Format:
1314 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1315
1316 pt. [PARIDE]
1317 See Documentation/paride.txt.
1318
1319 quiet= [KNL] Disable log messages
a9913044 1320
1da177e4
LT
1321 r128= [HW,DRM]
1322
1323 raid= [HW,RAID]
1324 See Documentation/md.txt.
1325
1326 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1327 See Documentation/ramdisk.txt.
1328
a9913044 1329 ramdisk_blocksize= [RAM]
1da177e4 1330 See Documentation/ramdisk.txt.
a9913044 1331
1da177e4
LT
1332 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1333 New name for the ramdisk parameter.
1334 See Documentation/ramdisk.txt.
1335
21a1ea9e
DS
1336 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1337 RCU callbacks to process in one batch.
1338
1339 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1340 RCU callbacks over which batch limiting is disabled.
1341
1342 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1343 RCU callbacks below which batch limiting is re-enabled.
1344
1345 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1346 RCU callbacks to queued before forcing reschedule
1347 on all cpus.
1348
ffdfc409
OJ
1349 rdinit= [KNL]
1350 Format: <full_path>
1351 Run specified binary instead of /init from the ramdisk,
1352 used for early userspace startup. See initrd.
1353
1da177e4
LT
1354 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1355 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1356 See arch/*/kernel/reboot.c.
1357
1358 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1359
a9913044
RD
1360 resume= [SWSUSP]
1361 Specify the partition device for software suspend
1da177e4
LT
1362
1363 rhash_entries= [KNL,NET]
1364 Set number of hash buckets for route cache
1365
1366 riscom8= [HW,SERIAL]
1367 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1368
1369 ro [KNL] Mount root device read-only on boot
1370
1371 root= [KNL] Root filesystem
1372
1373 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1374 mount the root filesystem
1375
1376 rootflags= [KNL] Set root filesystem mount option string
1377
1378 rootfstype= [KNL] Set root filesystem type
1379
1380 rw [KNL] Mount root device read-write on boot
1381
1382 S [KNL] Run init in single mode
1383
1384 sa1100ir [NET]
1385 See drivers/net/irda/sa1100_ir.c.
1386
1387 sb= [HW,OSS]
1388 Format: <io>,<irq>,<dma>,<dma2>
1389
1390 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1391
1da177e4
LT
1392 sbpcd= [HW,CD] Soundblaster CD adapter
1393 Format: <io>,<type>
1394 See a comment before function sbpcd_setup() in
1395 drivers/cdrom/sbpcd.c.
1396
1397 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1398 Format: <io>[,<timeout>[,<isapnp>]]
1399
1400 scsi_debug_*= [SCSI]
1401 See drivers/scsi/scsi_debug.c.
1402
1403 scsi_default_dev_flags=
1404 [SCSI] SCSI default device flags
1405 Format: <integer>
1406
1407 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1408 Format: <vendor>:<model>:<flags>
1409 (flags are integer value)
1410
1411 scsi_logging= [SCSI]
1412
1413 selinux [SELINUX] Disable or enable SELinux at boot time.
1414 Format: { "0" | "1" }
1415 See security/selinux/Kconfig help text.
1416 0 -- disable.
1417 1 -- enable.
1418 Default value is set via kernel config option.
1419 If enabled at boot time, /selinux/disable can be used
1420 later to disable prior to initial policy load.
1421
4e5ab4cb
JM
1422 selinux_compat_net =
1423 [SELINUX] Set initial selinux_compat_net flag value.
1424 Format: { "0" | "1" }
1425 0 -- use new secmark-based packet controls
1426 1 -- use legacy packet controls
1427 Default value is 0 (preferred).
1428 Value can be changed at runtime via
1429 /selinux/compat_net.
1430
1da177e4
LT
1431 serialnumber [BUGS=IA-32]
1432
a9913044
RD
1433 sg_def_reserved_size= [SCSI]
1434
1da177e4
LT
1435 sgalaxy= [HW,OSS]
1436 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1437
1438 shapers= [NET]
1439 Maximal number of shapers.
a9913044 1440
1da177e4
LT
1441 sim710= [SCSI,HW]
1442 See header of drivers/scsi/sim710.c.
1443
1444 simeth= [IA-64]
1445 simscsi=
a9913044 1446
1da177e4
LT
1447 sjcd= [HW,CD]
1448 Format: <io>,<irq>,<dma>
1449 See header of drivers/cdrom/sjcd.c.
1450
1451 slram= [HW,MTD]
1452
1453 smart2= [HW]
1454 Format: <io1>[,<io2>[,...,<io8>]]
1455
1456 snd-ad1816a= [HW,ALSA]
1457
1458 snd-ad1848= [HW,ALSA]
1459
1460 snd-ali5451= [HW,ALSA]
1461
1462 snd-als100= [HW,ALSA]
1463
1464 snd-als4000= [HW,ALSA]
1465
1466 snd-azt2320= [HW,ALSA]
1467
1468 snd-cmi8330= [HW,ALSA]
1469
1470 snd-cmipci= [HW,ALSA]
1471
1472 snd-cs4231= [HW,ALSA]
1473
1474 snd-cs4232= [HW,ALSA]
1475
1476 snd-cs4236= [HW,ALSA]
1477
1478 snd-cs4281= [HW,ALSA]
1479
1480 snd-cs46xx= [HW,ALSA]
1481
1482 snd-dt019x= [HW,ALSA]
1483
1484 snd-dummy= [HW,ALSA]
1485
1486 snd-emu10k1= [HW,ALSA]
1487
1488 snd-ens1370= [HW,ALSA]
1489
1490 snd-ens1371= [HW,ALSA]
1491
1492 snd-es968= [HW,ALSA]
1493
1494 snd-es1688= [HW,ALSA]
1495
1496 snd-es18xx= [HW,ALSA]
1497
1498 snd-es1938= [HW,ALSA]
1499
1500 snd-es1968= [HW,ALSA]
1501
1502 snd-fm801= [HW,ALSA]
1503
1504 snd-gusclassic= [HW,ALSA]
1505
1506 snd-gusextreme= [HW,ALSA]
1507
1508 snd-gusmax= [HW,ALSA]
1509
1510 snd-hdsp= [HW,ALSA]
1511
1512 snd-ice1712= [HW,ALSA]
1513
1514 snd-intel8x0= [HW,ALSA]
1515
1516 snd-interwave= [HW,ALSA]
1517
1518 snd-interwave-stb=
1519 [HW,ALSA]
1520
1521 snd-korg1212= [HW,ALSA]
1522
1523 snd-maestro3= [HW,ALSA]
1524
1525 snd-mpu401= [HW,ALSA]
1526
1527 snd-mtpav= [HW,ALSA]
1528
1529 snd-nm256= [HW,ALSA]
1530
1531 snd-opl3sa2= [HW,ALSA]
1532
1533 snd-opti92x-ad1848=
1534 [HW,ALSA]
1535
1536 snd-opti92x-cs4231=
1537 [HW,ALSA]
1538
1539 snd-opti93x= [HW,ALSA]
1540
1541 snd-pmac= [HW,ALSA]
1542
1543 snd-rme32= [HW,ALSA]
1544
1545 snd-rme96= [HW,ALSA]
1546
1547 snd-rme9652= [HW,ALSA]
1548
1549 snd-sb8= [HW,ALSA]
1550
1551 snd-sb16= [HW,ALSA]
1552
1553 snd-sbawe= [HW,ALSA]
1554
1555 snd-serial= [HW,ALSA]
1556
1557 snd-sgalaxy= [HW,ALSA]
1558
1559 snd-sonicvibes= [HW,ALSA]
1560
1561 snd-sun-amd7930=
1562 [HW,ALSA]
1563
1564 snd-sun-cs4231= [HW,ALSA]
1565
1566 snd-trident= [HW,ALSA]
1567
1568 snd-usb-audio= [HW,ALSA,USB]
1569
1570 snd-via82xx= [HW,ALSA]
1571
1572 snd-virmidi= [HW,ALSA]
1573
1574 snd-wavefront= [HW,ALSA]
1575
1576 snd-ymfpci= [HW,ALSA]
a9913044 1577
1da177e4
LT
1578 sonicvibes= [HW,OSS]
1579 Format: <reverb>
a9913044 1580
1da177e4
LT
1581 sonycd535= [HW,CD]
1582 Format: <io>[,<irq>]
1583
1584 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1585 See Documentation/sonypi.txt
1586
1587 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1588 See Documentation/specialix.txt.
1589
1590 spia_io_base= [HW,MTD]
1591 spia_fio_base=
1592 spia_pedr=
1593 spia_peddr=
1594
1595 sscape= [HW,OSS]
1596 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1597
1da177e4
LT
1598 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1599 See Documentation/scsi/st.txt.
1600
1601 st0x= [HW,SCSI]
1602 See header of drivers/scsi/seagate.c.
1603
1604 sti= [PARISC,HW]
1605 Format: <num>
1606 Set the STI (builtin display/keyboard on the HP-PARISC
1607 machines) console (graphic card) which should be used
1608 as the initial boot-console.
1609 See also comment in drivers/video/console/sticore.c.
1610
1611 sti_font= [HW]
1612 See comment in drivers/video/console/sticore.c.
1613
1614 stifb= [HW]
1615 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1616
1da177e4 1617 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1618
1da177e4
LT
1619 switches= [HW,M68k]
1620
1621 sym53c416= [HW,SCSI]
1622 See header of drivers/scsi/sym53c416.c.
1623
1624 t128= [HW,SCSI]
1625 See header of drivers/scsi/t128.c.
1626
1627 tdfx= [HW,DRM]
1628
1629 thash_entries= [KNL,NET]
1630 Set number of hash buckets for TCP connection
1631
1632 time Show timing data prefixed to each printk message line
1633
734efb46 1634 clocksource= [GENERIC_TIME] Override the default clocksource
1635 Override the default clocksource and use the clocksource
1636 with the name specified.
1637
1da177e4
LT
1638 tipar.timeout= [HW,PPT]
1639 Set communications timeout in tenths of a second
1640 (default 15).
1641
1642 tipar.delay= [HW,PPT]
1643 Set inter-bit delay in microseconds (default 10).
1644
1645 tmc8xx= [HW,SCSI]
1646 See header of drivers/scsi/seagate.c.
1647
1648 tmscsim= [HW,SCSI]
1649 See comment before function dc390_setup() in
1650 drivers/scsi/tmscsim.c.
1651
1652 tp720= [HW,PS2]
1653
1654 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1655 Format:
1656 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1657
1da177e4
LT
1658 tsdev.xres= [TS] Horizontal screen resolution.
1659 tsdev.yres= [TS] Vertical screen resolution.
1660
a9913044
RD
1661 turbografx.map[2|3]= [HW,JOY]
1662 TurboGraFX parallel port interface
1663 Format:
1664 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1665 See also Documentation/input/joystick-parport.txt
1666
1667 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1668 See header of drivers/scsi/u14-34f.c.
1669
1670 uart401= [HW,OSS]
1671 Format: <io>,<irq>
1672
1673 uart6850= [HW,OSS]
1674 Format: <io>,<irq>
1675
1da177e4
LT
1676 usbhid.mousepoll=
1677 [USBHID] The interval which mice are to be polled at.
a9913044 1678
e6e5494c
IM
1679 vdso= [IA-32]
1680 vdso=1: enable VDSO (default)
1681 vdso=0: disable VDSO mapping
1682
1da177e4
LT
1683 video= [FB] Frame buffer configuration
1684 See Documentation/fb/modedb.txt.
1685
1686 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1687 See Documentation/i386/boot.txt and
1688 Documentation/svga.txt.
1da177e4
LT
1689 Use vga=ask for menu.
1690 This is actually a boot loader parameter; the value is
1691 passed to the kernel using a special protocol.
1692
a9913044 1693 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1694 size of <nn>. This can be used to increase the
1695 minimum size (128MB on x86). It can also be used to
1696 decrease the size and leave more room for directly
1697 mapped kernel RAM.
1698
585c3047
PO
1699 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1700 Format: <command>
1da177e4 1701
585c3047
PO
1702 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1703 Format: <command>
1704
1705 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1706 Format: <command>
a9913044 1707
1da177e4
LT
1708 waveartist= [HW,OSS]
1709 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1710
1da177e4
LT
1711 wd33c93= [HW,SCSI]
1712 See header of drivers/scsi/wd33c93.c.
1713
1714 wd7000= [HW,SCSI]
1715 See header of drivers/scsi/wd7000.c.
1716
1717 wdt= [WDT] Watchdog
1718 See Documentation/watchdog/watchdog.txt.
1719
1720 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1721 xd_geo= See header of drivers/block/xd.c.
1722
1723 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1724 Format:
1725 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 1726
a62eaf15
AK
1727 norandmaps Don't use address space randomization
1728 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1729
1da177e4 1730
a9913044 1731______________________________________________________________________
1da177e4
LT
1732
1733TODO:
1734
1735 Add documentation for ALSA options.
1736 Add more DRM drivers.