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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
3
4 The 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
7 case insensitive manner), and with descriptions where known.
8
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14 Module parameters for modules that are built into the kernel image
15 are 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
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
31
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AX25 Appropriate AX.25 support is enabled.
38 BLACKFIN Blackfin architecture is enabled.
39 DRM Direct Rendering Management support is enabled.
40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LIBATA Libata driver is enabled
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD (Memory Technology Device) support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PV_OPS A paravirtualized kernel is enabled.
68 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
69 PARISC The PA-RISC architecture is enabled.
70 PCI PCI bus support is enabled.
71 PCMCIA The PCMCIA subsystem is enabled.
72 PNP Plug & Play support is enabled.
73 PPC PowerPC architecture is enabled.
74 PPT Parallel port support is enabled.
75 PS2 Appropriate PS/2 support is enabled.
76 RAM RAM disk support is enabled.
77 S390 S390 architecture is enabled.
78 SCSI Appropriate SCSI support is enabled.
79 A lot of drivers has their options described inside of
80 Documentation/scsi/.
81 SELINUX SELinux support is enabled.
82 SERIAL Serial support is enabled.
83 SH SuperH architecture is enabled.
84 SMP The kernel is an SMP kernel.
85 SPARC Sparc architecture is enabled.
86 SWSUSP Software suspend is enabled.
87 TS Appropriate touchscreen support is enabled.
88 USB USB support is enabled.
89 USBHID USB Human Interface Device support is enabled.
90 V4L Video For Linux support is enabled.
91 VGA The VGA console has been enabled.
92 VT Virtual terminal support is enabled.
93 WDT Watchdog support is enabled.
94 XT IBM PC/XT MFM hard disk support is enabled.
95 X86-32 X86-32, aka i386 architecture is enabled.
96 X86-64 X86-64 architecture is enabled.
97 More X86-64 boot options can be found in
98 Documentation/x86_64/boot-options.txt .
99
100 In addition, the following text indicates that the option:
101
102 BUGS= Relates to possible processor bugs on the said processor.
103 KNL Is a kernel start-up parameter.
104 BOOT Is a boot loader parameter.
105
106 Parameters denoted with BOOT are actually interpreted by the boot
107 loader, and have no meaning to the kernel directly.
108 Do not modify the syntax of boot loader parameters without extreme
109 need or coordination with <Documentation/i386/boot.txt>.
110
111 There are also arch-specific kernel-parameters not documented here.
112 See for example <Documentation/x86_64/boot-options.txt>.
113
114 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
115 a trailing = on the name of any parameter states that that parameter will
116 be entered as an environment variable, whereas its absence indicates that
117 it will appear as a kernel argument readable via /proc/cmdline by programs
118 running once the system is up.
119
120 The number of kernel parameters is not limited, but the length of the
121 complete command line (parameters including spaces etc.) is limited to
122 a fixed number of characters. This limit depends on the architecture
123 and is between 256 and 4096 characters. It is defined in the file
124 ./include/asm/setup.h as COMMAND_LINE_SIZE.
125
126
127 acpi= [HW,ACPI,X86-64,i386]
128 Advanced Configuration and Power Interface
129 Format: { force | off | ht | strict | noirq }
130 force -- enable ACPI if default was off
131 off -- disable ACPI if default was on
132 noirq -- do not use ACPI for IRQ routing
133 ht -- run only enough ACPI to enable Hyper Threading
134 strict -- Be less tolerant of platforms that are not
135 strictly ACPI specification compliant.
136
137 See also Documentation/pm.txt, pci=noacpi
138
139 acpi_apic_instance= [ACPI, IOAPIC]
140 Format: <int>
141 2: use 2nd APIC table, if available
142 1,0: use 1st APIC table
143 default: 0
144
145 acpi_sleep= [HW,ACPI] Sleep options
146 Format: { s3_bios, s3_mode }
147 See Documentation/power/video.txt
148
149 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
150 Format: { level | edge | high | low }
151
152 acpi_irq_balance [HW,ACPI]
153 ACPI will balance active IRQs
154 default in APIC mode
155
156 acpi_irq_nobalance [HW,ACPI]
157 ACPI will not move active IRQs (default)
158 default in PIC mode
159
160 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
161 use by PCI
162 Format: <irq>,<irq>...
163
164 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
165 Format: <irq>,<irq>...
166
167 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
168
169 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
170 Format: To spoof as Windows 98: ="Microsoft Windows"
171
172 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
173 acpi_osi="string1" # add string1 -- only one string
174 acpi_osi="!string2" # remove built-in string2
175 acpi_osi= # disable all strings
176
177 acpi_serialize [HW,ACPI] force serialization of AML methods
178
179 acpi_skip_timer_override [HW,ACPI]
180 Recognize and ignore IRQ0/pin2 Interrupt Override.
181 For broken nForce2 BIOS resulting in XT-PIC timer.
182 acpi_use_timer_override [HW,ACPI}
183 Use timer override. For some broken Nvidia NF5 boards
184 that require a timer override, but don't have
185 HPET
186
187 acpi.debug_layer= [HW,ACPI]
188 Format: <int>
189 Each bit of the <int> indicates an ACPI debug layer,
190 1: enable, 0: disable. It is useful for boot time
191 debugging. After system has booted up, it can be set
192 via /sys/module/acpi/parameters/debug_layer.
193 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
194 Available bits (add the numbers together) to enable debug output
195 for specific parts of the ACPI subsystem:
196 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
197 0x10 namespace 0x20 parser 0x40 dispatcher
198 0x80 executer 0x100 resources 0x200 acpica debugger
199 0x400 os services 0x800 acpica disassembler.
200 The number can be in decimal or prefixed with 0x in hex.
201 Warning: Many of these options can produce a lot of
202 output and make your system unusable. Be very careful.
203
204 acpi.debug_level= [HW,ACPI]
205 Format: <int>
206 Each bit of the <int> indicates an ACPI debug level,
207 1: enable, 0: disable. It is useful for boot time
208 debugging. After system has booted up, it can be set
209 via /sys/module/acpi/parameters/debug_level.
210 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
211 Available bits (add the numbers together) to enable different
212 debug output levels of the ACPI subsystem:
213 0x01 error 0x02 warn 0x04 init 0x08 debug object
214 0x10 info 0x20 init names 0x40 parse 0x80 load
215 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
216 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
217 0x10000 resources 0x20000 user requests 0x40000 package.
218 The number can be in decimal or prefixed with 0x in hex.
219 Warning: Many of these options can produce a lot of
220 output and make your system unusable. Be very careful.
221
222
223 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
224
225 acpi_pm_good [X86-32,X86-64]
226 Override the pmtimer bug detection: force the kernel
227 to assume that this machine's pmtimer latches its value
228 and always returns good values.
229
230 agp= [AGP]
231 { off | try_unsupported }
232 off: disable AGP support
233 try_unsupported: try to drive unsupported chipsets
234 (may crash computer or cause data corruption)
235
236 enable_timer_pin_1 [i386,x86-64]
237 Enable PIN 1 of APIC timer
238 Can be useful to work around chipset bugs
239 (in particular on some ATI chipsets).
240 The kernel tries to set a reasonable default.
241
242 disable_timer_pin_1 [i386,x86-64]
243 Disable PIN 1 of APIC timer
244 Can be useful to work around chipset bugs.
245
246 ad1848= [HW,OSS]
247 Format: <io>,<irq>,<dma>,<dma2>,<type>
248
249 advansys= [HW,SCSI]
250 See header of drivers/scsi/advansys.c.
251
252 advwdt= [HW,WDT] Advantech WDT
253 Format: <iostart>,<iostop>
254
255 aedsp16= [HW,OSS] Audio Excel DSP 16
256 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
257 See also header of sound/oss/aedsp16.c.
258
259 aha152x= [HW,SCSI]
260 See Documentation/scsi/aha152x.txt.
261
262 aha1542= [HW,SCSI]
263 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
264
265 aic7xxx= [HW,SCSI]
266 See Documentation/scsi/aic7xxx.txt.
267
268 aic79xx= [HW,SCSI]
269 See Documentation/scsi/aic79xx.txt.
270
271 amijoy.map= [HW,JOY] Amiga joystick support
272 Map of devices attached to JOY0DAT and JOY1DAT
273 Format: <a>,<b>
274 See also Documentation/kernel/input/joystick.txt
275
276 analog.map= [HW,JOY] Analog joystick and gamepad support
277 Specifies type or capabilities of an analog joystick
278 connected to one of 16 gameports
279 Format: <type1>,<type2>,..<type16>
280
281 apc= [HW,SPARC]
282 Power management functions (SPARCstation-4/5 + deriv.)
283 Format: noidle
284 Disable APC CPU standby support. SPARCstation-Fox does
285 not play well with APC CPU idle - disable it if you have
286 APC and your system crashes randomly.
287
288 apic= [APIC,i386] Advanced Programmable Interrupt Controller
289 Change the output verbosity whilst booting
290 Format: { quiet (default) | verbose | debug }
291 Change the amount of debugging information output
292 when initialising the APIC and IO-APIC components.
293
294 apm= [APM] Advanced Power Management
295 See header of arch/i386/kernel/apm.c.
296
297 applicom= [HW]
298 Format: <mem>,<irq>
299
300 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
301 Format: <io>,<irq>,<nodeID>
302
303 ataflop= [HW,M68k]
304
305 atarimouse= [HW,MOUSE] Atari Mouse
306
307 atascsi= [HW,SCSI] Atari SCSI
308
309 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
310 EzKey and similar keyboards
311
312 atkbd.reset= [HW] Reset keyboard during initialization
313
314 atkbd.set= [HW] Select keyboard code set
315 Format: <int> (2 = AT (default), 3 = PS/2)
316
317 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
318 keyboards
319
320 atkbd.softraw= [HW] Choose between synthetic and real raw mode
321 Format: <bool> (0 = real, 1 = synthetic (default))
322
323 atkbd.softrepeat= [HW]
324 Use software keyboard repeat
325
326 autotest [IA64]
327
328 baycom_epp= [HW,AX25]
329 Format: <io>,<mode>
330
331 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
332 Format: <io>,<mode>
333 See header of drivers/net/hamradio/baycom_par.c.
334
335 baycom_ser_fdx= [HW,AX25]
336 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
337 Format: <io>,<irq>,<mode>[,<baud>]
338 See header of drivers/net/hamradio/baycom_ser_fdx.c.
339
340 baycom_ser_hdx= [HW,AX25]
341 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
342 Format: <io>,<irq>,<mode>
343 See header of drivers/net/hamradio/baycom_ser_hdx.c.
344
345 blkmtd_device= [HW,MTD]
346 blkmtd_erasesz=
347 blkmtd_ro=
348 blkmtd_bs=
349 blkmtd_count=
350
351 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
352 bttv.radio= Most important insmod options are available as
353 kernel args too.
354 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
355 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
356
357 BusLogic= [HW,SCSI]
358 See drivers/scsi/BusLogic.c, comment before function
359 BusLogic_ParseDriverOptions().
360
361 c101= [NET] Moxa C101 synchronous serial card
362
363 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
364 Sometimes CPU hardware bugs make them report the cache
365 size incorrectly. The kernel will attempt work arounds
366 to fix known problems, but for some CPUs it is not
367 possible to determine what the correct size should be.
368 This option provides an override for these situations.
369
370 chandev= [HW,NET] Generic channel device initialisation
371
372 checkreqprot [SELINUX] Set initial checkreqprot flag value.
373 Format: { "0" | "1" }
374 See security/selinux/Kconfig help text.
375 0 -- check protection applied by kernel (includes
376 any implied execute protection).
377 1 -- check protection requested by application.
378 Default value is set via a kernel config option.
379 Value can be changed at runtime via
380 /selinux/checkreqprot.
381
382 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
383 [Deprecated]
384 Forces specified clocksource (if available) to be used
385 when calculating gettimeofday(). If specified
386 clocksource is not available, it defaults to PIT.
387 Format: { pit | tsc | cyclone | pmtmr }
388
389 clocksource= [GENERIC_TIME] Override the default clocksource
390 Format: <string>
391 Override the default clocksource and use the clocksource
392 with the name specified.
393 Some clocksource names to choose from, depending on
394 the platform:
395 [all] jiffies (this is the base, fallback clocksource)
396 [ACPI] acpi_pm
397 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
398 pxa_timer,timer3,32k_counter,timer0_1
399 [AVR32] avr32
400 [X86-32] pit,hpet,tsc,vmi-timer;
401 scx200_hrt on Geode; cyclone on IBM x440
402 [MIPS] MIPS
403 [PARISC] cr16
404 [S390] tod
405 [SH] SuperH
406 [SPARC64] tick
407 [X86-64] hpet,tsc
408
409 code_bytes [IA32] How many bytes of object code to print in an
410 oops report.
411 Range: 0 - 8192
412 Default: 64
413
414 disable_8254_timer
415 enable_8254_timer
416 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
417 over the 8254 in addition to over the IO-APIC. The
418 kernel tries to set a sensible default.
419
420 hpet= [X86-32,HPET] option to disable HPET and use PIT.
421 Format: disable
422
423 com20020= [HW,NET] ARCnet - COM20020 chipset
424 Format:
425 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
426
427 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
428 Format: <io>[,<irq>]
429
430 com90xx= [HW,NET]
431 ARCnet - COM90xx chipset (memory-mapped buffers)
432 Format: <io>[,<irq>[,<memstart>]]
433
434 condev= [HW,S390] console device
435 conmode=
436
437 console= [KNL] Output console device and options.
438
439 tty<n> Use the virtual console device <n>.
440
441 ttyS<n>[,options]
442 ttyUSB0[,options]
443 Use the specified serial port. The options are of
444 the form "bbbbpnf", where "bbbb" is the baud rate,
445 "p" is parity ("n", "o", or "e"), "n" is number of
446 bits, and "f" is flow control ("r" for RTS or
447 omit it). Default is "9600n8".
448
449 See Documentation/serial-console.txt for more
450 information. See
451 Documentation/networking/netconsole.txt for an
452 alternative.
453
454 uart[8250],io,<addr>[,options]
455 uart[8250],mmio,<addr>[,options]
456 Start an early, polled-mode console on the 8250/16550
457 UART at the specified I/O port or MMIO address,
458 switching to the matching ttyS device later. The
459 options are the same as for ttyS, above.
460
461 earlycon= [KNL] Output early console device and options.
462 uart[8250],io,<addr>[,options]
463 uart[8250],mmio,<addr>[,options]
464 Start an early, polled-mode console on the 8250/16550
465 UART at the specified I/O port or MMIO address.
466 The options are the same as for ttyS, above.
467
468 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
469 Format:
470 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
471
472 crashkernel=nn[KMG]@ss[KMG]
473 [KNL] Reserve a chunk of physical memory to
474 hold a kernel to switch to with kexec on panic.
475
476 cs4232= [HW,OSS]
477 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
478
479 cs89x0_dma= [HW,NET]
480 Format: <dma>
481
482 cs89x0_media= [HW,NET]
483 Format: { rj45 | aui | bnc }
484
485 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
486
487 dasd= [HW,NET]
488 See header of drivers/s390/block/dasd_devmap.c.
489
490 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
491 (one device per port)
492 Format: <port#>,<type>
493 See also Documentation/input/joystick-parport.txt
494
495 debug [KNL] Enable kernel debugging (events log level).
496
497 debug_locks_verbose=
498 [KNL] verbose self-tests
499 Format=<0|1>
500 Print debugging info while doing the locking API
501 self-tests.
502 We default to 0 (no extra messages), setting it to
503 1 will print _a lot_ more information - normally
504 only useful to kernel developers.
505
506 decnet= [HW,NET]
507 Format: <area>[,<node>]
508 See also Documentation/networking/decnet.txt.
509
510 default_blu= [VT]
511 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
512 Change the default blue palette of the console.
513 This is a 16-member array composed of values
514 ranging from 0-255.
515
516 default_grn= [VT]
517 Format: <green0>,<green1>,<green2>,...,<green15>
518 Change the default green palette of the console.
519 This is a 16-member array composed of values
520 ranging from 0-255.
521
522 default_red= [VT]
523 Format: <red0>,<red1>,<red2>,...,<red15>
524 Change the default red palette of the console.
525 This is a 16-member array composed of values
526 ranging from 0-255.
527
528 default_utf8= [VT]
529 Format=<0|1>
530 Set system-wide default UTF-8 mode for all tty's.
531 Default is 0 and by setting to 1, it enables UTF-8
532 mode for all newly opened or allocated terminals.
533
534 dhash_entries= [KNL]
535 Set number of hash buckets for dentry cache.
536
537 digi= [HW,SERIAL]
538 IO parameters + enable/disable command.
539
540 digiepca= [HW,SERIAL]
541 See drivers/char/README.epca and
542 Documentation/digiepca.txt.
543
544 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
545 support available.
546 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
547
548 dmasound= [HW,OSS] Sound subsystem buffers
549
550 dscc4.setup= [NET]
551
552 dtc3181e= [HW,SCSI]
553
554 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
555 earlyprintk=vga
556 earlyprintk=serial[,ttySn[,baudrate]]
557
558 Append ",keep" to not disable it when the real console
559 takes over.
560
561 Only vga or serial at a time, not both.
562
563 Currently only ttyS0 and ttyS1 are supported.
564
565 Interaction with the standard serial driver is not
566 very good.
567
568 The VGA output is eventually overwritten by the real
569 console.
570
571 eata= [HW,SCSI]
572
573 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
574 Format: <int>
575 0: polling mode
576 non-0: interrupt mode (default)
577
578 eda= [HW,PS2]
579
580 edb= [HW,PS2]
581
582 edd= [EDD]
583 Format: {"of[f]" | "sk[ipmbr]"}
584 See comment in arch/i386/boot/edd.S
585
586 eicon= [HW,ISDN]
587 Format: <id>,<membase>,<irq>
588
589 eisa_irq_edge= [PARISC,HW]
590 See header of drivers/parisc/eisa.c.
591
592 elanfreq= [X86-32]
593 See comment before function elanfreq_setup() in
594 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
595
596 elevator= [IOSCHED]
597 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
598 See Documentation/block/as-iosched.txt and
599 Documentation/block/deadline-iosched.txt for details.
600
601 elfcorehdr= [X86-32, X86_64]
602 Specifies physical address of start of kernel core
603 image elf header. Generally kexec loader will
604 pass this option to capture kernel.
605 See Documentation/kdump/kdump.txt for details.
606
607 enforcing [SELINUX] Set initial enforcing status.
608 Format: {"0" | "1"}
609 See security/selinux/Kconfig help text.
610 0 -- permissive (log only, no denials).
611 1 -- enforcing (deny and log).
612 Default value is 0.
613 Value can be changed at runtime via /selinux/enforce.
614
615 es1371= [HW,OSS]
616 Format: <spdif>,[<nomix>,[<amplifier>]]
617 See also header of sound/oss/es1371.c.
618
619 ether= [HW,NET] Ethernet cards parameters
620 This option is obsoleted by the "netdev=" option, which
621 has equivalent usage. See its documentation for details.
622
623 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
624 Format: <io>[,<irq>]
625
626 failslab=
627 fail_page_alloc=
628 fail_make_request=[KNL]
629 General fault injection mechanism.
630 Format: <interval>,<probability>,<space>,<times>
631 See also /Documentation/fault-injection/.
632
633 fd_mcs= [HW,SCSI]
634 See header of drivers/scsi/fd_mcs.c.
635
636 fdomain= [HW,SCSI]
637 See header of drivers/scsi/fdomain.c.
638
639 floppy= [HW]
640 See Documentation/floppy.txt.
641
642 gamecon.map[2|3]=
643 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
644 support via parallel port (up to 5 devices per port)
645 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
646 See also Documentation/input/joystick-parport.txt
647
648 gamma= [HW,DRM]
649
650 gdth= [HW,SCSI]
651 See header of drivers/scsi/gdth.c.
652
653 gpt [EFI] Forces disk with valid GPT signature but
654 invalid Protective MBR to be treated as GPT.
655
656 gvp11= [HW,SCSI]
657
658 hashdist= [KNL,NUMA] Large hashes allocated during boot
659 are distributed across NUMA nodes. Defaults on
660 for IA-64, off otherwise.
661 Format: 0 | 1 (for off | on)
662
663 hcl= [IA-64] SGI's Hardware Graph compatibility layer
664
665 hd= [EIDE] (E)IDE hard drive subsystem geometry
666 Format: <cyl>,<head>,<sect>
667
668 hd?= [HW] (E)IDE subsystem
669 hd?lun= See Documentation/ide.txt.
670
671 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
672 size of <nn>. This works even on boxes that have no
673 highmem otherwise. This also works to reduce highmem
674 size on bigger boxes.
675
676 highres= [KNL] Enable/disable high resolution timer mode.
677 Valid parameters: "on", "off"
678 Default: "on"
679
680 hisax= [HW,ISDN]
681 See Documentation/isdn/README.HiSax.
682
683 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
684
685 i8042.direct [HW] Put keyboard port into non-translated mode
686 i8042.dumbkbd [HW] Pretend that controller can only read data from
687 keyboard and cannot control its state
688 (Don't attempt to blink the leds)
689 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
690 i8042.nokbd [HW] Don't check/create keyboard port
691 i8042.nomux [HW] Don't check presence of an active multiplexing
692 controller
693 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
694 controllers
695 i8042.panicblink=
696 [HW] Frequency with which keyboard LEDs should blink
697 when kernel panics (default is 0.5 sec)
698 i8042.reset [HW] Reset the controller during init and cleanup
699 i8042.unlock [HW] Unlock (ignore) the keylock
700
701 i810= [HW,DRM]
702
703 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
704 indicates that the driver is running on unsupported
705 hardware.
706 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
707 does not match list of supported models.
708 i8k.power_status
709 [HW] Report power status in /proc/i8k
710 (disabled by default)
711 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
712 capability is set.
713
714 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
715 See Documentation/mca.txt.
716
717 icn= [HW,ISDN]
718 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
719
720 ide= [HW] (E)IDE subsystem
721 Format: ide=nodma or ide=doubler or ide=reverse
722 See Documentation/ide.txt.
723
724 ide?= [HW] (E)IDE subsystem
725 Format: ide?=noprobe or chipset specific parameters.
726 See Documentation/ide.txt.
727
728 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
729 See Documentation/ide.txt.
730
731 idle= [X86]
732 Format: idle=poll or idle=mwait
733 Poll forces a polling idle loop that can slightly improves the performance
734 of waking up a idle CPU, but will use a lot of power and make the system
735 run hot. Not recommended.
736 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
737 to not use it because it doesn't save as much power as a normal idle
738 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
739 as idle=poll.
740
741 ignore_loglevel [KNL]
742 Ignore loglevel setting - this will print /all/
743 kernel messages to the console. Useful for debugging.
744
745 ihash_entries= [KNL]
746 Set number of hash buckets for inode cache.
747
748 in2000= [HW,SCSI]
749 See header of drivers/scsi/in2000.c.
750
751 init= [KNL]
752 Format: <full_path>
753 Run specified binary instead of /sbin/init as init
754 process.
755
756 initcall_debug [KNL] Trace initcalls as they are executed. Useful
757 for working out where the kernel is dying during
758 startup.
759
760 initrd= [BOOT] Specify the location of the initial ramdisk
761
762 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
763 Format: <irq>
764
765 inttest= [IA64]
766
767 io7= [HW] IO7 for Marvel based alpha systems
768 See comment before marvel_specify_io7 in
769 arch/alpha/kernel/core_marvel.c.
770
771 ip= [IP_PNP]
772 See Documentation/nfsroot.txt.
773
774 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
775 See comment before ip2_setup() in
776 drivers/char/ip2/ip2base.c.
777
778 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
779 See header of drivers/scsi/ips.c.
780
781 ports= [IP_VS_FTP] IPVS ftp helper module
782 Default is 21.
783 Up to 8 (IP_VS_APP_MAX_PORTS) ports
784 may be specified.
785 Format: <port>,<port>....
786
787 irqfixup [HW]
788 When an interrupt is not handled search all handlers
789 for it. Intended to get systems with badly broken
790 firmware running.
791
792 irqpoll [HW]
793 When an interrupt is not handled search all handlers
794 for it. Also check all handlers each timer
795 interrupt. Intended to get systems with badly broken
796 firmware running.
797
798 isapnp= [ISAPNP]
799 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
800
801 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
802 Format:
803 <cpu number>,...,<cpu number>
804 or
805 <cpu number>-<cpu number> (must be a positive range in ascending order)
806 or a mixture
807 <cpu number>,...,<cpu number>-<cpu number>
808 This option can be used to specify one or more CPUs
809 to isolate from the general SMP balancing and scheduling
810 algorithms. The only way to move a process onto or off
811 an "isolated" CPU is via the CPU affinity syscalls.
812 <cpu number> begins at 0 and the maximum value is
813 "number of CPUs in system - 1".
814
815 This option is the preferred way to isolate CPUs. The
816 alternative -- manually setting the CPU mask of all
817 tasks in the system -- can cause problems and
818 suboptimal load balancer performance.
819
820 iucv= [HW,NET]
821
822 js= [HW,JOY] Analog joystick
823 See Documentation/input/joystick.txt.
824
825 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
826 specifies the amount of memory usable by the kernel
827 for non-movable allocations. The requested amount is
828 spread evenly throughout all nodes in the system. The
829 remaining memory in each node is used for Movable
830 pages. In the event, a node is too small to have both
831 kernelcore and Movable pages, kernelcore pages will
832 take priority and other nodes will have a larger number
833 of kernelcore pages. The Movable zone is used for the
834 allocation of pages that may be reclaimed or moved
835 by the page migration subsystem. This means that
836 HugeTLB pages may not be allocated from this zone.
837 Note that allocations like PTEs-from-HighMem still
838 use the HighMem zone if it exists, and the Normal
839 zone if it does not.
840
841 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
842 is similar to kernelcore except it specifies the
843 amount of memory used for migratable allocations.
844 If both kernelcore and movablecore is specified,
845 then kernelcore will be at *least* the specified
846 value but may be more. If movablecore on its own
847 is specified, the administrator must be careful
848 that the amount of memory usable for all allocations
849 is not too small.
850
851 keepinitrd [HW,ARM]
852
853 kstack=N [X86-32,X86-64] Print N words from the kernel stack
854 in oops dumps.
855
856 l2cr= [PPC]
857
858 lapic [X86-32,APIC] Enable the local APIC even if BIOS
859 disabled it.
860
861 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
862 C2 power state.
863
864 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
865 Format: addr:<io>,irq:<irq>
866
867 load_ramdisk= [RAM] List of ramdisks to load from floppy
868 See Documentation/ramdisk.txt.
869
870 lockd.nlm_grace_period=P [NFS] Assign grace period.
871 Format: <integer>
872
873 lockd.nlm_tcpport=N [NFS] Assign TCP port.
874 Format: <integer>
875
876 lockd.nlm_timeout=T [NFS] Assign timeout value.
877 Format: <integer>
878
879 lockd.nlm_udpport=M [NFS] Assign UDP port.
880 Format: <integer>
881
882 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
883 Format: <irq>
884
885 loglevel= All Kernel Messages with a loglevel smaller than the
886 console loglevel will be printed to the console. It can
887 also be changed with klogd or other programs. The
888 loglevels are defined as follows:
889
890 0 (KERN_EMERG) system is unusable
891 1 (KERN_ALERT) action must be taken immediately
892 2 (KERN_CRIT) critical conditions
893 3 (KERN_ERR) error conditions
894 4 (KERN_WARNING) warning conditions
895 5 (KERN_NOTICE) normal but significant condition
896 6 (KERN_INFO) informational
897 7 (KERN_DEBUG) debug-level messages
898
899 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
900 Format: { n | nk | nM }
901 n must be a power of two. The default size
902 is set in the kernel config file.
903
904 lp=0 [LP] Specify parallel ports to use, e.g,
905 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
906 lp=reset first parallel port). 'lp=0' disables the
907 lp=auto printer driver. 'lp=reset' (which can be
908 specified in addition to the ports) causes
909 attached printers to be reset. Using
910 lp=port1,port2,... specifies the parallel ports
911 to associate lp devices with, starting with
912 lp0. A port specification may be 'none' to skip
913 that lp device, or a parport name such as
914 'parport0'. Specifying 'lp=auto' instead of a
915 port specification list means that device IDs
916 from each port should be examined, to see if
917 an IEEE 1284-compliant printer is attached; if
918 so, the driver will manage that printer.
919 See also header of drivers/char/lp.c.
920
921 lpj=n [KNL]
922 Sets loops_per_jiffy to given constant, thus avoiding
923 time-consuming boot-time autodetection (up to 250 ms per
924 CPU). 0 enables autodetection (default). To determine
925 the correct value for your kernel, boot with normal
926 autodetection and see what value is printed. Note that
927 on SMP systems the preset will be applied to all CPUs,
928 which is likely to cause problems if your CPUs need
929 significantly divergent settings. An incorrect value
930 will cause delays in the kernel to be wrong, leading to
931 unpredictable I/O errors and other breakage. Although
932 unlikely, in the extreme case this might damage your
933 hardware.
934
935 ltpc= [NET]
936 Format: <io>,<irq>,<dma>
937
938 mac5380= [HW,SCSI] Format:
939 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
940
941 mac53c9x= [HW,SCSI] Format:
942 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
943
944 machvec= [IA64] Force the use of a particular machine-vector
945 (machvec) in a generic kernel.
946 Example: machvec=hpzx1_swiotlb
947
948 max_loop= [LOOP] Maximum number of loopback devices that can
949 be mounted
950 Format: <1-256>
951
952 maxcpus= [SMP] Maximum number of processors that an SMP kernel
953 should make use of. maxcpus=n : n >= 0 limits the
954 kernel to using 'n' processors. n=0 is a special case,
955 it is equivalent to "nosmp", which also disables
956 the IO APIC.
957
958 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
959 equal to this physical address is ignored.
960
961 max_luns= [SCSI] Maximum number of LUNs to probe.
962 Should be between 1 and 2^32-1.
963
964 max_report_luns=
965 [SCSI] Maximum number of LUNs received.
966 Should be between 1 and 16384.
967
968 mca-pentium [BUGS=X86-32]
969
970 mcatest= [IA-64]
971
972 mce [X86-32] Machine Check Exception
973
974 md= [HW] RAID subsystems devices and level
975 See Documentation/md.txt.
976
977 mdacon= [MDA]
978 Format: <first>,<last>
979 Specifies range of consoles to be captured by the MDA.
980
981 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
982 Amount of memory to be used when the kernel is not able
983 to see the whole system memory or for test.
984 [X86-32] Use together with memmap= to avoid physical
985 address space collisions. Without memmap= PCI devices
986 could be placed at addresses belonging to unused RAM.
987
988 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
989 memory.
990
991 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
992 E820 memory map, as specified by the user.
993 Such memmap=exactmap lines can be constructed based on
994 BIOS output or other requirements. See the memmap=nn@ss
995 option description.
996
997 memmap=nn[KMG]@ss[KMG]
998 [KNL] Force usage of a specific region of memory
999 Region of memory to be used, from ss to ss+nn.
1000
1001 memmap=nn[KMG]#ss[KMG]
1002 [KNL,ACPI] Mark specific memory as ACPI data.
1003 Region of memory to be used, from ss to ss+nn.
1004
1005 memmap=nn[KMG]$ss[KMG]
1006 [KNL,ACPI] Mark specific memory as reserved.
1007 Region of memory to be used, from ss to ss+nn.
1008
1009 meye.*= [HW] Set MotionEye Camera parameters
1010 See Documentation/video4linux/meye.txt.
1011
1012 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1013 Multi-Function General Purpose Timers on AMD Geode
1014 platforms.
1015
1016 mga= [HW,DRM]
1017
1018 mousedev.tap_time=
1019 [MOUSE] Maximum time between finger touching and
1020 leaving touchpad surface for touch to be considered
1021 a tap and be reported as a left button click (for
1022 touchpads working in absolute mode only).
1023 Format: <msecs>
1024 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1025 reporting absolute coordinates, such as tablets
1026 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1027 reporting absolute coordinates, such as tablets
1028
1029 mpu401= [HW,OSS]
1030 Format: <io>,<irq>
1031
1032 MTD_Partition= [MTD]
1033 Format: <name>,<region-number>,<size>,<offset>
1034
1035 MTD_Region= [MTD] Format:
1036 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1037
1038 mtdparts= [MTD]
1039 See drivers/mtd/cmdlinepart.c.
1040
1041 mtouchusb.raw_coordinates=
1042 [HW] Make the MicroTouch USB driver use raw coordinates
1043 ('y', default) or cooked coordinates ('n')
1044
1045 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1046
1047 NCR_D700= [HW,SCSI]
1048 See header of drivers/scsi/NCR_D700.c.
1049
1050 ncr5380= [HW,SCSI]
1051
1052 ncr53c400= [HW,SCSI]
1053
1054 ncr53c400a= [HW,SCSI]
1055
1056 ncr53c406a= [HW,SCSI]
1057
1058 ncr53c8xx= [HW,SCSI]
1059
1060 netdev= [NET] Network devices parameters
1061 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1062 Note that mem_start is often overloaded to mean
1063 something different and driver-specific.
1064 This usage is only documented in each driver source
1065 file if at all.
1066
1067 nfsaddrs= [NFS]
1068 See Documentation/nfsroot.txt.
1069
1070 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1071 See Documentation/nfsroot.txt.
1072
1073 nfs.callback_tcpport=
1074 [NFS] set the TCP port on which the NFSv4 callback
1075 channel should listen.
1076
1077 nfs.idmap_cache_timeout=
1078 [NFS] set the maximum lifetime for idmapper cache
1079 entries.
1080
1081 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1082
1083 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1084 emulation library even if a 387 maths coprocessor
1085 is present.
1086
1087 noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1088 when set.
1089 Format: <int>
1090
1091 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1092 caches in the slab allocator. Saves per-node memory,
1093 but will impact performance.
1094
1095 noalign [KNL,ARM]
1096
1097 noapic [SMP,APIC] Tells the kernel to not make use of any
1098 IOAPICs that may be present in the system.
1099
1100 noasync [HW,M68K] Disables async and sync negotiation for
1101 all devices.
1102
1103 nobats [PPC] Do not use BATs for mapping kernel lowmem
1104 on "Classic" PPC cores.
1105
1106 nocache [ARM]
1107
1108 nodelayacct [KNL] Disable per-task delay accounting
1109
1110 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1111
1112 noexec [IA-64]
1113
1114 noexec [X86-32,X86-64]
1115 noexec=on: enable non-executable mappings (default)
1116 noexec=off: disable nn-executable mappings
1117
1118 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1119 register save and restore. The kernel will only save
1120 legacy floating-point registers on task switch.
1121
1122 nohlt [BUGS=ARM]
1123
1124 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1125 instruction doesn't work correctly and not to
1126 use it.
1127
1128 nohalt [IA-64] Tells the kernel not to use the power saving
1129 function PAL_HALT_LIGHT when idle. This increases
1130 power-consumption. On the positive side, it reduces
1131 interrupt wake-up latency, which may improve performance
1132 in certain environments such as networked servers or
1133 real-time systems.
1134
1135 nohz= [KNL] Boottime enable/disable dynamic ticks
1136 Valid arguments: on, off
1137 Default: on
1138
1139 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1140
1141 noirqdebug [X86-32] Disables the code which attempts to detect and
1142 disable unhandled interrupt sources.
1143
1144 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1145 broken timer IRQ sources.
1146
1147 noisapnp [ISAPNP] Disables ISA PnP code.
1148
1149 noinitrd [RAM] Tells the kernel not to load any configured
1150 initial RAM disk.
1151
1152 nointroute [IA-64]
1153
1154 nojitter [IA64] Disables jitter checking for ITC timers.
1155
1156 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1157
1158 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1159
1160 noltlbs [PPC] Do not use large page/tlb entries for kernel
1161 lowmem mapping on PPC40x.
1162
1163 nomca [IA-64] Disable machine check abort handling
1164
1165 nomce [X86-32] Machine Check Exception
1166
1167 nomfgpt [X86-32] Disable Multi-Function General Purpose
1168 Timer usage (for AMD Geode machines).
1169
1170 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1171
1172 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1173 with UP alternatives
1174
1175 noresidual [PPC] Don't use residual data on PReP machines.
1176
1177 noresume [SWSUSP] Disables resume and restores original swap
1178 space.
1179
1180 no-scroll [VGA] Disables scrollback.
1181 This is required for the Braillex ib80-piezo Braille
1182 reader made by F.H. Papenmeier (Germany).
1183
1184 nosbagart [IA-64]
1185
1186 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1187
1188 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1189 and disable the IO APIC. legacy for "maxcpus=0".
1190
1191 nosoftlockup [KNL] Disable the soft-lockup detector.
1192
1193 nosync [HW,M68K] Disables sync negotiation for all devices.
1194
1195 notsc [BUGS=X86-32] Disable Time Stamp Counter
1196
1197 nousb [USB] Disable the USB subsystem
1198
1199 nowb [ARM]
1200
1201 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1202 one of ['zone', 'node', 'default'] can be specified
1203 This can be set from sysctl after boot.
1204 See Documentation/sysctl/vm.txt for details.
1205
1206 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1207
1208 opl3= [HW,OSS]
1209 Format: <io>
1210
1211 oprofile.timer= [HW]
1212 Use timer interrupt instead of performance counters
1213
1214 osst= [HW,SCSI] SCSI Tape Driver
1215 Format: <buffer_size>,<write_threshold>
1216 See also Documentation/scsi/st.txt.
1217
1218 panic= [KNL] Kernel behaviour on panic
1219 Format: <timeout>
1220
1221 parkbd.port= [HW] Parallel port number the keyboard adapter is
1222 connected to, default is 0.
1223 Format: <parport#>
1224 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1225 0 for XT, 1 for AT (default is AT).
1226 Format: <mode>
1227
1228 parport= [HW,PPT] Specify parallel ports. 0 disables.
1229 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1230 Use 'auto' to force the driver to use any
1231 IRQ/DMA settings detected (the default is to
1232 ignore detected IRQ/DMA settings because of
1233 possible conflicts). You can specify the base
1234 address, IRQ, and DMA settings; IRQ and DMA
1235 should be numbers, or 'auto' (for using detected
1236 settings on that particular port), or 'nofifo'
1237 (to avoid using a FIFO even if it is detected).
1238 Parallel ports are assigned in the order they
1239 are specified on the command line, starting
1240 with parport0.
1241
1242 parport_init_mode= [HW,PPT]
1243 Configure VIA parallel port to operate in
1244 a specific mode. This is necessary on Pegasos
1245 computer where firmware has no options for setting
1246 up parallel port mode and sets it to spp.
1247 Currently this function knows 686a and 8231 chips.
1248 Format: [spp|ps2|epp|ecp|ecpepp]
1249
1250 pas2= [HW,OSS] Format:
1251 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1252
1253 pas16= [HW,SCSI]
1254 See header of drivers/scsi/pas16.c.
1255
1256 pause_on_oops=
1257 Halt all CPUs after the first oops has been printed for
1258 the specified number of seconds. This is to be used if
1259 your oopses keep scrolling off the screen.
1260
1261 pcbit= [HW,ISDN]
1262
1263 pcd. [PARIDE]
1264 See header of drivers/block/paride/pcd.c.
1265 See also Documentation/paride.txt.
1266
1267 pci=option[,option...] [PCI] various PCI subsystem options:
1268 off [X86-32] don't probe for the PCI bus
1269 bios [X86-32] force use of PCI BIOS, don't access
1270 the hardware directly. Use this if your machine
1271 has a non-standard PCI host bridge.
1272 nobios [X86-32] disallow use of PCI BIOS, only direct
1273 hardware access methods are allowed. Use this
1274 if you experience crashes upon bootup and you
1275 suspect they are caused by the BIOS.
1276 conf1 [X86-32] Force use of PCI Configuration
1277 Mechanism 1.
1278 conf2 [X86-32] Force use of PCI Configuration
1279 Mechanism 2.
1280 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1281 Configuration
1282 nomsi [MSI] If the PCI_MSI kernel config parameter is
1283 enabled, this kernel boot option can be used to
1284 disable the use of MSI interrupts system-wide.
1285 nosort [X86-32] Don't sort PCI devices according to
1286 order given by the PCI BIOS. This sorting is
1287 done to get a device order compatible with
1288 older kernels.
1289 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1290 routing table. These calls are known to be buggy
1291 on several machines and they hang the machine
1292 when used, but on other computers it's the only
1293 way to get the interrupt routing table. Try
1294 this option if the kernel is unable to allocate
1295 IRQs or discover secondary PCI buses on your
1296 motherboard.
1297 rom [X86-32] Assign address space to expansion ROMs.
1298 Use with caution as certain devices share
1299 address decoders between ROMs and other
1300 resources.
1301 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1302 assigned automatically to PCI devices. You can
1303 make the kernel exclude IRQs of your ISA cards
1304 this way.
1305 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1306 of the PIRQ table (normally generated
1307 by the BIOS) if it is outside the
1308 F0000h-100000h range.
1309 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1310 useful if the kernel is unable to find your
1311 secondary buses and you want to tell it
1312 explicitly which ones they are.
1313 assign-busses [X86-32] Always assign all PCI bus
1314 numbers ourselves, overriding
1315 whatever the firmware may have done.
1316 usepirqmask [X86-32] Honor the possible IRQ mask stored
1317 in the BIOS $PIR table. This is needed on
1318 some systems with broken BIOSes, notably
1319 some HP Pavilion N5400 and Omnibook XE3
1320 notebooks. This will have no effect if ACPI
1321 IRQ routing is enabled.
1322 noacpi [X86-32] Do not use ACPI for IRQ routing
1323 or for PCI scanning.
1324 routeirq Do IRQ routing for all PCI devices.
1325 This is normally done in pci_enable_device(),
1326 so this option is a temporary workaround
1327 for broken drivers that don't call it.
1328 firmware [ARM] Do not re-enumerate the bus but instead
1329 just use the configuration from the
1330 bootloader. This is currently used on
1331 IXP2000 systems where the bus has to be
1332 configured a certain way for adjunct CPUs.
1333 noearly [X86] Don't do any early type 1 scanning.
1334 This might help on some broken boards which
1335 machine check when some devices' config space
1336 is read. But various workarounds are disabled
1337 and some IOMMU drivers will not work.
1338 bfsort Sort PCI devices into breadth-first order.
1339 This sorting is done to get a device
1340 order compatible with older (<= 2.4) kernels.
1341 nobfsort Don't sort PCI devices into breadth-first order.
1342 cbiosize=nn[KMG] The fixed amount of bus space which is
1343 reserved for the CardBus bridge's IO window.
1344 The default value is 256 bytes.
1345 cbmemsize=nn[KMG] The fixed amount of bus space which is
1346 reserved for the CardBus bridge's memory
1347 window. The default value is 64 megabytes.
1348
1349 pcmv= [HW,PCMCIA] BadgePAD 4
1350
1351 pd. [PARIDE]
1352 See Documentation/paride.txt.
1353
1354 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1355 boot time.
1356 Format: { 0 | 1 }
1357 See arch/parisc/kernel/pdc_chassis.c
1358
1359 pf. [PARIDE]
1360 See Documentation/paride.txt.
1361
1362 pg. [PARIDE]
1363 See Documentation/paride.txt.
1364
1365 pirq= [SMP,APIC] Manual mp-table setup
1366 See Documentation/i386/IO-APIC.txt.
1367
1368 plip= [PPT,NET] Parallel port network link
1369 Format: { parport<nr> | timid | 0 }
1370 See also Documentation/parport.txt.
1371
1372 pnpacpi= [ACPI]
1373 { off }
1374
1375 pnpbios= [ISAPNP]
1376 { on | off | curr | res | no-curr | no-res }
1377
1378 pnp_reserve_irq=
1379 [ISAPNP] Exclude IRQs for the autoconfiguration
1380
1381 pnp_reserve_dma=
1382 [ISAPNP] Exclude DMAs for the autoconfiguration
1383
1384 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1385 Ranges are in pairs (I/O port base and size).
1386
1387 pnp_reserve_mem=
1388 [ISAPNP] Exclude memory regions for the
1389 autoconfiguration.
1390 Ranges are in pairs (memory base and size).
1391
1392 print-fatal-signals=
1393 [KNL] debug: print fatal signals
1394 print-fatal-signals=1: print segfault info to
1395 the kernel console.
1396 default: off.
1397
1398 printk.time= Show timing data prefixed to each printk message line
1399 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1400
1401 profile= [KNL] Enable kernel profiling via /proc/profile
1402 Format: [schedule,]<number>
1403 Param: "schedule" - profile schedule points.
1404 Param: <number> - step/bucket size as a power of 2 for
1405 statistical time based profiling.
1406 Param: "sleep" - profile D-state sleeping (millisecs)
1407
1408 processor.max_cstate= [HW,ACPI]
1409 Limit processor to maximum C-state
1410 max_cstate=9 overrides any DMI blacklist limit.
1411
1412 processor.nocst [HW,ACPI]
1413 Ignore the _CST method to determine C-states,
1414 instead using the legacy FADT method
1415
1416 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1417 before loading.
1418 See Documentation/ramdisk.txt.
1419
1420 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1421 probe for; one of (bare|imps|exps|lifebook|any).
1422 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1423 per second.
1424 psmouse.resetafter= [HW,MOUSE]
1425 Try to reset the device after so many bad packets
1426 (0 = never).
1427 psmouse.resolution=
1428 [HW,MOUSE] Set desired mouse resolution, in dpi.
1429 psmouse.smartscroll=
1430 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1431 0 = disabled, 1 = enabled (default).
1432
1433 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1434 Format:
1435 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1436
1437 pt. [PARIDE]
1438 See Documentation/paride.txt.
1439
1440 quiet [KNL] Disable most log messages
1441
1442 r128= [HW,DRM]
1443
1444 raid= [HW,RAID]
1445 See Documentation/md.txt.
1446
1447 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1448 See Documentation/ramdisk.txt.
1449
1450 ramdisk_blocksize= [RAM]
1451 See Documentation/ramdisk.txt.
1452
1453 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1454 New name for the ramdisk parameter.
1455 See Documentation/ramdisk.txt.
1456
1457 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1458 RCU callbacks to process in one batch.
1459
1460 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1461 RCU callbacks over which batch limiting is disabled.
1462
1463 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1464 RCU callbacks below which batch limiting is re-enabled.
1465
1466 rdinit= [KNL]
1467 Format: <full_path>
1468 Run specified binary instead of /init from the ramdisk,
1469 used for early userspace startup. See initrd.
1470
1471 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1472 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1473 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1474
1475 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1476
1477 reservetop= [X86-32]
1478 Format: nn[KMG]
1479 Reserves a hole at the top of the kernel virtual
1480 address space.
1481
1482 reset_devices [KNL] Force drivers to reset the underlying device
1483 during initialization.
1484
1485 resume= [SWSUSP]
1486 Specify the partition device for software suspend
1487
1488 resume_offset= [SWSUSP]
1489 Specify the offset from the beginning of the partition
1490 given by "resume=" at which the swap header is located,
1491 in <PAGE_SIZE> units (needed only for swap files).
1492 See Documentation/power/swsusp-and-swap-files.txt
1493
1494 retain_initrd [RAM] Keep initrd memory after extraction
1495
1496 rhash_entries= [KNL,NET]
1497 Set number of hash buckets for route cache
1498
1499 riscom8= [HW,SERIAL]
1500 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1501
1502 ro [KNL] Mount root device read-only on boot
1503
1504 root= [KNL] Root filesystem
1505
1506 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1507 mount the root filesystem
1508
1509 rootflags= [KNL] Set root filesystem mount option string
1510
1511 rootfstype= [KNL] Set root filesystem type
1512
1513 rootwait [KNL] Wait (indefinitely) for root device to show up.
1514 Useful for devices that are detected asynchronously
1515 (e.g. USB and MMC devices).
1516
1517 rw [KNL] Mount root device read-write on boot
1518
1519 S [KNL] Run init in single mode
1520
1521 sa1100ir [NET]
1522 See drivers/net/irda/sa1100_ir.c.
1523
1524 sb= [HW,OSS]
1525 Format: <io>,<irq>,<dma>,<dma2>
1526
1527 sbni= [NET] Granch SBNI12 leased line adapter
1528
1529 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1530 Format: <io>[,<timeout>[,<isapnp>]]
1531
1532 scsi_debug_*= [SCSI]
1533 See drivers/scsi/scsi_debug.c.
1534
1535 scsi_default_dev_flags=
1536 [SCSI] SCSI default device flags
1537 Format: <integer>
1538
1539 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1540 Format: <vendor>:<model>:<flags>
1541 (flags are integer value)
1542
1543 scsi_logging= [SCSI]
1544
1545 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1546 discovered. async scans them in kernel threads,
1547 allowing boot to proceed. none ignores them, expecting
1548 user space to do the scan.
1549
1550 selinux [SELINUX] Disable or enable SELinux at boot time.
1551 Format: { "0" | "1" }
1552 See security/selinux/Kconfig help text.
1553 0 -- disable.
1554 1 -- enable.
1555 Default value is set via kernel config option.
1556 If enabled at boot time, /selinux/disable can be used
1557 later to disable prior to initial policy load.
1558
1559 selinux_compat_net =
1560 [SELINUX] Set initial selinux_compat_net flag value.
1561 Format: { "0" | "1" }
1562 0 -- use new secmark-based packet controls
1563 1 -- use legacy packet controls
1564 Default value is 0 (preferred).
1565 Value can be changed at runtime via
1566 /selinux/compat_net.
1567
1568 serialnumber [BUGS=X86-32]
1569
1570 sg_def_reserved_size= [SCSI]
1571
1572 shapers= [NET]
1573 Maximal number of shapers.
1574
1575 sim710= [SCSI,HW]
1576 See header of drivers/scsi/sim710.c.
1577
1578 simeth= [IA-64]
1579 simscsi=
1580
1581 slram= [HW,MTD]
1582
1583 slub_debug[=options[,slabs]] [MM, SLUB]
1584 Enabling slub_debug allows one to determine the
1585 culprit if slab objects become corrupted. Enabling
1586 slub_debug can create guard zones around objects and
1587 may poison objects when not in use. Also tracks the
1588 last alloc / free. For more information see
1589 Documentation/vm/slub.txt.
1590
1591 slub_max_order= [MM, SLUB]
1592 Determines the maximum allowed order for slabs.
1593 A high setting may cause OOMs due to memory
1594 fragmentation. For more information see
1595 Documentation/vm/slub.txt.
1596
1597 slub_min_objects= [MM, SLUB]
1598 The minimum number of objects per slab. SLUB will
1599 increase the slab order up to slub_max_order to
1600 generate a sufficiently large slab able to contain
1601 the number of objects indicated. The higher the number
1602 of objects the smaller the overhead of tracking slabs
1603 and the less frequently locks need to be acquired.
1604 For more information see Documentation/vm/slub.txt.
1605
1606 slub_min_order= [MM, SLUB]
1607 Determines the mininum page order for slabs. Must be
1608 lower than slub_max_order.
1609 For more information see Documentation/vm/slub.txt.
1610
1611 slub_nomerge [MM, SLUB]
1612 Disable merging of slabs with similar size. May be
1613 necessary if there is some reason to distinguish
1614 allocs to different slabs. Debug options disable
1615 merging on their own.
1616 For more information see Documentation/vm/slub.txt.
1617
1618 smart2= [HW]
1619 Format: <io1>[,<io2>[,...,<io8>]]
1620
1621 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1622 attempt to substitute SMP alternatives once at boot.
1623
1624 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1625 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1626 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1627 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1628 smsc-ircc2.ircc_irq= [HW] IRQ line
1629 smsc-ircc2.ircc_dma= [HW] DMA channel
1630 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1631 0: Toshiba Satellite 1800 (GP data pin select)
1632 1: Fast pin select (default)
1633 2: ATC IRMode
1634
1635 snd-ad1816a= [HW,ALSA]
1636
1637 snd-ad1848= [HW,ALSA]
1638
1639 snd-ali5451= [HW,ALSA]
1640
1641 snd-als100= [HW,ALSA]
1642
1643 snd-als4000= [HW,ALSA]
1644
1645 snd-azt2320= [HW,ALSA]
1646
1647 snd-cmi8330= [HW,ALSA]
1648
1649 snd-cmipci= [HW,ALSA]
1650
1651 snd-cs4231= [HW,ALSA]
1652
1653 snd-cs4232= [HW,ALSA]
1654
1655 snd-cs4236= [HW,ALSA]
1656
1657 snd-cs4281= [HW,ALSA]
1658
1659 snd-cs46xx= [HW,ALSA]
1660
1661 snd-dt019x= [HW,ALSA]
1662
1663 snd-dummy= [HW,ALSA]
1664
1665 snd-emu10k1= [HW,ALSA]
1666
1667 snd-ens1370= [HW,ALSA]
1668
1669 snd-ens1371= [HW,ALSA]
1670
1671 snd-es968= [HW,ALSA]
1672
1673 snd-es1688= [HW,ALSA]
1674
1675 snd-es18xx= [HW,ALSA]
1676
1677 snd-es1938= [HW,ALSA]
1678
1679 snd-es1968= [HW,ALSA]
1680
1681 snd-fm801= [HW,ALSA]
1682
1683 snd-gusclassic= [HW,ALSA]
1684
1685 snd-gusextreme= [HW,ALSA]
1686
1687 snd-gusmax= [HW,ALSA]
1688
1689 snd-hdsp= [HW,ALSA]
1690
1691 snd-ice1712= [HW,ALSA]
1692
1693 snd-intel8x0= [HW,ALSA]
1694
1695 snd-interwave= [HW,ALSA]
1696
1697 snd-interwave-stb=
1698 [HW,ALSA]
1699
1700 snd-korg1212= [HW,ALSA]
1701
1702 snd-maestro3= [HW,ALSA]
1703
1704 snd-mpu401= [HW,ALSA]
1705
1706 snd-mtpav= [HW,ALSA]
1707
1708 snd-nm256= [HW,ALSA]
1709
1710 snd-opl3sa2= [HW,ALSA]
1711
1712 snd-opti92x-ad1848=
1713 [HW,ALSA]
1714
1715 snd-opti92x-cs4231=
1716 [HW,ALSA]
1717
1718 snd-opti93x= [HW,ALSA]
1719
1720 snd-pmac= [HW,ALSA]
1721
1722 snd-rme32= [HW,ALSA]
1723
1724 snd-rme96= [HW,ALSA]
1725
1726 snd-rme9652= [HW,ALSA]
1727
1728 snd-sb8= [HW,ALSA]
1729
1730 snd-sb16= [HW,ALSA]
1731
1732 snd-sbawe= [HW,ALSA]
1733
1734 snd-serial= [HW,ALSA]
1735
1736 snd-sgalaxy= [HW,ALSA]
1737
1738 snd-sonicvibes= [HW,ALSA]
1739
1740 snd-sun-amd7930=
1741 [HW,ALSA]
1742
1743 snd-sun-cs4231= [HW,ALSA]
1744
1745 snd-trident= [HW,ALSA]
1746
1747 snd-usb-audio= [HW,ALSA,USB]
1748
1749 snd-via82xx= [HW,ALSA]
1750
1751 snd-virmidi= [HW,ALSA]
1752
1753 snd-wavefront= [HW,ALSA]
1754
1755 snd-ymfpci= [HW,ALSA]
1756
1757 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1758 See Documentation/sonypi.txt
1759
1760 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1761 See Documentation/specialix.txt.
1762
1763 spia_io_base= [HW,MTD]
1764 spia_fio_base=
1765 spia_pedr=
1766 spia_peddr=
1767
1768 sscape= [HW,OSS]
1769 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1770
1771 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1772 See Documentation/scsi/st.txt.
1773
1774 st0x= [HW,SCSI]
1775 See header of drivers/scsi/seagate.c.
1776
1777 sti= [PARISC,HW]
1778 Format: <num>
1779 Set the STI (builtin display/keyboard on the HP-PARISC
1780 machines) console (graphic card) which should be used
1781 as the initial boot-console.
1782 See also comment in drivers/video/console/sticore.c.
1783
1784 sti_font= [HW]
1785 See comment in drivers/video/console/sticore.c.
1786
1787 stifb= [HW]
1788 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1789
1790 sunrpc.pool_mode=
1791 [NFS]
1792 Control how the NFS server code allocates CPUs to
1793 service thread pools. Depending on how many NICs
1794 you have and where their interrupts are bound, this
1795 option will affect which CPUs will do NFS serving.
1796 Note: this parameter cannot be changed while the
1797 NFS server is running.
1798
1799 auto the server chooses an appropriate mode
1800 automatically using heuristics
1801 global a single global pool contains all CPUs
1802 percpu one pool for each CPU
1803 pernode one pool for each NUMA node (equivalent
1804 to global on non-NUMA machines)
1805
1806 swiotlb= [IA-64] Number of I/O TLB slabs
1807
1808 switches= [HW,M68k]
1809
1810 sym53c416= [HW,SCSI]
1811 See header of drivers/scsi/sym53c416.c.
1812
1813 sysrq_always_enabled
1814 [KNL]
1815 Ignore sysrq setting - this boot parameter will
1816 neutralize any effect of /proc/sys/kernel/sysrq.
1817 Useful for debugging.
1818
1819 t128= [HW,SCSI]
1820 See header of drivers/scsi/t128.c.
1821
1822 tdfx= [HW,DRM]
1823
1824 thash_entries= [KNL,NET]
1825 Set number of hash buckets for TCP connection
1826
1827 thermal.act= [HW,ACPI]
1828 -1: disable all active trip points in all thermal zones
1829 <degrees C>: override all lowest active trip points
1830
1831 thermal.crt= [HW,ACPI]
1832 -1: disable all critical trip points in all thermal zones
1833 <degrees C>: lower all critical trip points
1834
1835 thermal.nocrt= [HW,ACPI]
1836 Set to disable actions on ACPI thermal zone
1837 critical and hot trip points.
1838
1839 thermal.off= [HW,ACPI]
1840 1: disable ACPI thermal control
1841
1842 thermal.psv= [HW,ACPI]
1843 -1: disable all passive trip points
1844 <degrees C>: override all passive trip points to this value
1845
1846 thermal.tzp= [HW,ACPI]
1847 Specify global default ACPI thermal zone polling rate
1848 <deci-seconds>: poll all this frequency
1849 0: no polling (default)
1850
1851 time Show timing data prefixed to each printk message line
1852 [deprecated, see 'printk.time']
1853
1854 tipar.timeout= [HW,PPT]
1855 Set communications timeout in tenths of a second
1856 (default 15).
1857
1858 tipar.delay= [HW,PPT]
1859 Set inter-bit delay in microseconds (default 10).
1860
1861 tmc8xx= [HW,SCSI]
1862 See header of drivers/scsi/seagate.c.
1863
1864 tmscsim= [HW,SCSI]
1865 See comment before function dc390_setup() in
1866 drivers/scsi/tmscsim.c.
1867
1868 tp720= [HW,PS2]
1869
1870 trix= [HW,OSS] MediaTrix AudioTrix Pro
1871 Format:
1872 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1873
1874 tsdev.xres= [TS] Horizontal screen resolution.
1875 tsdev.yres= [TS] Vertical screen resolution.
1876
1877 turbografx.map[2|3]= [HW,JOY]
1878 TurboGraFX parallel port interface
1879 Format:
1880 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1881 See also Documentation/input/joystick-parport.txt
1882
1883 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1884 See header of drivers/scsi/u14-34f.c.
1885
1886 uart401= [HW,OSS]
1887 Format: <io>,<irq>
1888
1889 uart6850= [HW,OSS]
1890 Format: <io>,<irq>
1891
1892 uhci-hcd.ignore_oc=
1893 [USB] Ignore overcurrent events (default N).
1894 Some badly-designed motherboards generate lots of
1895 bogus events, for ports that aren't wired to
1896 anything. Set this parameter to avoid log spamming.
1897 Note that genuine overcurrent events won't be
1898 reported either.
1899
1900 usbcore.autosuspend=
1901 [USB] The autosuspend time delay (in seconds) used
1902 for newly-detected USB devices (default 2). This
1903 is the time required before an idle device will be
1904 autosuspended. Devices for which the delay is set
1905 to a negative value won't be autosuspended at all.
1906
1907 usbhid.mousepoll=
1908 [USBHID] The interval which mice are to be polled at.
1909
1910 vdso= [X86-32,SH,x86-64]
1911 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1912 vdso=1: enable VDSO (default)
1913 vdso=0: disable VDSO mapping
1914
1915 vector= [IA-64,SMP]
1916 vector=percpu: enable percpu vector domain
1917
1918 video= [FB] Frame buffer configuration
1919 See Documentation/fb/modedb.txt.
1920
1921 vga= [BOOT,X86-32] Select a particular video mode
1922 See Documentation/i386/boot.txt and
1923 Documentation/svga.txt.
1924 Use vga=ask for menu.
1925 This is actually a boot loader parameter; the value is
1926 passed to the kernel using a special protocol.
1927
1928 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1929 size of <nn>. This can be used to increase the
1930 minimum size (128MB on x86). It can also be used to
1931 decrease the size and leave more room for directly
1932 mapped kernel RAM.
1933
1934 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1935 Format: <command>
1936
1937 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1938 Format: <command>
1939
1940 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1941 Format: <command>
1942
1943 waveartist= [HW,OSS]
1944 Format: <io>,<irq>,<dma>,<dma2>
1945
1946 wd33c93= [HW,SCSI]
1947 See header of drivers/scsi/wd33c93.c.
1948
1949 wd7000= [HW,SCSI]
1950 See header of drivers/scsi/wd7000.c.
1951
1952 wdt= [WDT] Watchdog
1953 See Documentation/watchdog/wdt.txt.
1954
1955 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1956 xd_geo= See header of drivers/block/xd.c.
1957
1958 xirc2ps_cs= [NET,PCMCIA]
1959 Format:
1960 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1961
1962 norandmaps Don't use address space randomization
1963 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1964
1965 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
1966 This is useful to get more information why
1967 you got a "dwarf2 unwinder stuck"
1968
1969 ______________________________________________________________________
1970
1971 TODO:
1972
1973 Add documentation for ALSA options.
1974 Add more DRM drivers.