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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
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.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
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:
18 usbcore.blinkenlights=1
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}".
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:
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 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LIBATA Libata driver is enabled
53 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
61 MSI Message Signaled Interrupts (PCI).
62 MTD MTD (Memory Technology Device) support is enabled.
63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
65 GENERIC_TIME The generic timeofday code is enabled.
66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
72 PCIE PCI Express support is enabled.
73 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
79 ROOTPLUG The example Root Plug LSM is enabled.
80 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
83 Documentation/scsi/.
84 SECURITY Different security models are enabled.
85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
87 SH SuperH architecture is enabled.
88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
90 SWSUSP Software suspend is enabled.
91 TS Appropriate touchscreen support is enabled.
92 USB USB support is enabled.
93 USBHID USB Human Interface Device support is enabled.
94 V4L Video For Linux support is enabled.
95 VGA The VGA console has been enabled.
96 VT Virtual terminal support is enabled.
97 WDT Watchdog support is enabled.
98 XT IBM PC/XT MFM hard disk support is enabled.
99 X86-32 X86-32, aka i386 architecture is enabled.
100 X86-64 X86-64 architecture is enabled.
101 More X86-64 boot options can be found in
102 Documentation/x86_64/boot-options.txt .
104 In addition, the following text indicates that the option:
106 BUGS= Relates to possible processor bugs on the said processor.
107 KNL Is a kernel start-up parameter.
108 BOOT Is a boot loader parameter.
110 Parameters denoted with BOOT are actually interpreted by the boot
111 loader, and have no meaning to the kernel directly.
112 Do not modify the syntax of boot loader parameters without extreme
113 need or coordination with <Documentation/i386/boot.txt>.
115 There are also arch-specific kernel-parameters not documented here.
116 See for example <Documentation/x86_64/boot-options.txt>.
118 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
119 a trailing = on the name of any parameter states that that parameter will
120 be entered as an environment variable, whereas its absence indicates that
121 it will appear as a kernel argument readable via /proc/cmdline by programs
122 running once the system is up.
124 The number of kernel parameters is not limited, but the length of the
125 complete command line (parameters including spaces etc.) is limited to
126 a fixed number of characters. This limit depends on the architecture
127 and is between 256 and 4096 characters. It is defined in the file
128 ./include/asm/setup.h as COMMAND_LINE_SIZE.
131 acpi= [HW,ACPI,X86-64,i386]
132 Advanced Configuration and Power Interface
133 Format: { force | off | ht | strict | noirq }
134 force -- enable ACPI if default was off
135 off -- disable ACPI if default was on
136 noirq -- do not use ACPI for IRQ routing
137 ht -- run only enough ACPI to enable Hyper Threading
138 strict -- Be less tolerant of platforms that are not
139 strictly ACPI specification compliant.
141 See also Documentation/pm.txt, pci=noacpi
143 acpi_apic_instance= [ACPI, IOAPIC]
144 Format: <int>
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
147 default: 0
149 acpi_sleep= [HW,ACPI] Sleep options
150 Format: { s3_bios, s3_mode }
151 See Documentation/power/video.txt
153 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
154 Format: { level | edge | high | low }
156 acpi_irq_balance [HW,ACPI]
157 ACPI will balance active IRQs
158 default in APIC mode
160 acpi_irq_nobalance [HW,ACPI]
161 ACPI will not move active IRQs (default)
162 default in PIC mode
164 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
165 use by PCI
166 Format: <irq>,<irq>...
168 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
169 Format: <irq>,<irq>...
171 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
173 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
174 Format: To spoof as Windows 98: ="Microsoft Windows"
176 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
177 acpi_osi="string1" # add string1 -- only one string
178 acpi_osi="!string2" # remove built-in string2
179 acpi_osi= # disable all strings
181 acpi_serialize [HW,ACPI] force serialization of AML methods
183 acpi_skip_timer_override [HW,ACPI]
184 Recognize and ignore IRQ0/pin2 Interrupt Override.
185 For broken nForce2 BIOS resulting in XT-PIC timer.
186 acpi_use_timer_override [HW,ACPI}
187 Use timer override. For some broken Nvidia NF5 boards
188 that require a timer override, but don't have
189 HPET
191 acpi.debug_layer= [HW,ACPI]
192 Format: <int>
193 Each bit of the <int> indicates an ACPI debug layer,
194 1: enable, 0: disable. It is useful for boot time
195 debugging. After system has booted up, it can be set
196 via /sys/module/acpi/parameters/debug_layer.
197 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
198 Available bits (add the numbers together) to enable debug output
199 for specific parts of the ACPI subsystem:
200 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
201 0x10 namespace 0x20 parser 0x40 dispatcher
202 0x80 executer 0x100 resources 0x200 acpica debugger
203 0x400 os services 0x800 acpica disassembler.
204 The number can be in decimal or prefixed with 0x in hex.
205 Warning: Many of these options can produce a lot of
206 output and make your system unusable. Be very careful.
208 acpi.debug_level= [HW,ACPI]
209 Format: <int>
210 Each bit of the <int> indicates an ACPI debug level,
211 1: enable, 0: disable. It is useful for boot time
212 debugging. After system has booted up, it can be set
213 via /sys/module/acpi/parameters/debug_level.
214 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
215 Available bits (add the numbers together) to enable different
216 debug output levels of the ACPI subsystem:
217 0x01 error 0x02 warn 0x04 init 0x08 debug object
218 0x10 info 0x20 init names 0x40 parse 0x80 load
219 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
220 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
221 0x10000 resources 0x20000 user requests 0x40000 package.
222 The number can be in decimal or prefixed with 0x in hex.
223 Warning: Many of these options can produce a lot of
224 output and make your system unusable. Be very careful.
226 acpi_pm_good [X86-32,X86-64]
227 Override the pmtimer bug detection: force the kernel
228 to assume that this machine's pmtimer latches its value
229 and always returns good values.
231 agp= [AGP]
232 { off | try_unsupported }
233 off: disable AGP support
234 try_unsupported: try to drive unsupported chipsets
235 (may crash computer or cause data corruption)
237 enable_timer_pin_1 [i386,x86-64]
238 Enable PIN 1 of APIC timer
239 Can be useful to work around chipset bugs
240 (in particular on some ATI chipsets).
241 The kernel tries to set a reasonable default.
243 disable_timer_pin_1 [i386,x86-64]
244 Disable PIN 1 of APIC timer
245 Can be useful to work around chipset bugs.
247 ad1848= [HW,OSS]
248 Format: <io>,<irq>,<dma>,<dma2>,<type>
250 advansys= [HW,SCSI]
251 See header of drivers/scsi/advansys.c.
253 advwdt= [HW,WDT] Advantech WDT
254 Format: <iostart>,<iostop>
256 aedsp16= [HW,OSS] Audio Excel DSP 16
257 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
258 See also header of sound/oss/aedsp16.c.
260 aha152x= [HW,SCSI]
261 See Documentation/scsi/aha152x.txt.
263 aha1542= [HW,SCSI]
264 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
266 aic7xxx= [HW,SCSI]
267 See Documentation/scsi/aic7xxx.txt.
269 aic79xx= [HW,SCSI]
270 See Documentation/scsi/aic79xx.txt.
272 amijoy.map= [HW,JOY] Amiga joystick support
273 Map of devices attached to JOY0DAT and JOY1DAT
274 Format: <a>,<b>
275 See also Documentation/kernel/input/joystick.txt
277 analog.map= [HW,JOY] Analog joystick and gamepad support
278 Specifies type or capabilities of an analog joystick
279 connected to one of 16 gameports
280 Format: <type1>,<type2>,..<type16>
282 apc= [HW,SPARC]
283 Power management functions (SPARCstation-4/5 + deriv.)
284 Format: noidle
285 Disable APC CPU standby support. SPARCstation-Fox does
286 not play well with APC CPU idle - disable it if you have
287 APC and your system crashes randomly.
289 apic= [APIC,i386] Advanced Programmable Interrupt Controller
290 Change the output verbosity whilst booting
291 Format: { quiet (default) | verbose | debug }
292 Change the amount of debugging information output
293 when initialising the APIC and IO-APIC components.
295 apm= [APM] Advanced Power Management
296 See header of arch/i386/kernel/apm.c.
298 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
299 Format: <io>,<irq>,<nodeID>
301 ataflop= [HW,M68k]
303 atarimouse= [HW,MOUSE] Atari Mouse
305 atascsi= [HW,SCSI] Atari SCSI
307 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
308 EzKey and similar keyboards
310 atkbd.reset= [HW] Reset keyboard during initialization
312 atkbd.set= [HW] Select keyboard code set
313 Format: <int> (2 = AT (default), 3 = PS/2)
315 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
316 keyboards
318 atkbd.softraw= [HW] Choose between synthetic and real raw mode
319 Format: <bool> (0 = real, 1 = synthetic (default))
321 atkbd.softrepeat= [HW]
322 Use software keyboard repeat
324 autotest [IA64]
326 baycom_epp= [HW,AX25]
327 Format: <io>,<mode>
329 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
330 Format: <io>,<mode>
331 See header of drivers/net/hamradio/baycom_par.c.
333 baycom_ser_fdx= [HW,AX25]
334 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
335 Format: <io>,<irq>,<mode>[,<baud>]
336 See header of drivers/net/hamradio/baycom_ser_fdx.c.
338 baycom_ser_hdx= [HW,AX25]
339 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
340 Format: <io>,<irq>,<mode>
341 See header of drivers/net/hamradio/baycom_ser_hdx.c.
343 boot_delay= Milliseconds to delay each printk during boot.
344 Values larger than 10 seconds (10000) are changed to
345 no delay (0).
346 Format: integer
348 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
349 bttv.radio= Most important insmod options are available as
350 kernel args too.
351 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
352 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
354 BusLogic= [HW,SCSI]
355 See drivers/scsi/BusLogic.c, comment before function
356 BusLogic_ParseDriverOptions().
358 c101= [NET] Moxa C101 synchronous serial card
360 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
361 Sometimes CPU hardware bugs make them report the cache
362 size incorrectly. The kernel will attempt work arounds
363 to fix known problems, but for some CPUs it is not
364 possible to determine what the correct size should be.
365 This option provides an override for these situations.
367 capability.disable=
368 [SECURITY] Disable capabilities. This would normally
369 be used only if an alternative security model is to be
370 configured. Potentially dangerous and should only be
371 used if you are entirely sure of the consequences.
373 ccw_timeout_log [S390]
374 See Documentation/s390/CommonIO for details.
376 checkreqprot [SELINUX] Set initial checkreqprot flag value.
377 Format: { "0" | "1" }
378 See security/selinux/Kconfig help text.
379 0 -- check protection applied by kernel (includes
380 any implied execute protection).
381 1 -- check protection requested by application.
382 Default value is set via a kernel config option.
383 Value can be changed at runtime via
384 /selinux/checkreqprot.
386 cio_ignore= [S390]
387 See Documentation/s390/CommonIO for details.
389 cio_msg= [S390]
390 See Documentation/s390/CommonIO for details.
392 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
393 [Deprecated]
394 Forces specified clocksource (if available) to be used
395 when calculating gettimeofday(). If specified
396 clocksource is not available, it defaults to PIT.
397 Format: { pit | tsc | cyclone | pmtmr }
399 clocksource= [GENERIC_TIME] Override the default clocksource
400 Format: <string>
401 Override the default clocksource and use the clocksource
402 with the name specified.
403 Some clocksource names to choose from, depending on
404 the platform:
405 [all] jiffies (this is the base, fallback clocksource)
406 [ACPI] acpi_pm
407 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
408 pxa_timer,timer3,32k_counter,timer0_1
409 [AVR32] avr32
410 [X86-32] pit,hpet,tsc,vmi-timer;
411 scx200_hrt on Geode; cyclone on IBM x440
412 [MIPS] MIPS
413 [PARISC] cr16
414 [S390] tod
415 [SH] SuperH
416 [SPARC64] tick
417 [X86-64] hpet,tsc
419 code_bytes [IA32] How many bytes of object code to print in an
420 oops report.
421 Range: 0 - 8192
422 Default: 64
424 disable_8254_timer
425 enable_8254_timer
426 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
427 over the 8254 in addition to over the IO-APIC. The
428 kernel tries to set a sensible default.
430 hpet= [X86-32,HPET] option to control HPET usage
431 Format: { enable (default) | disable | force }
432 disable: disable HPET and use PIT instead
433 force: allow force enabled of undocumented chips (ICH4,
434 VIA, nVidia)
436 com20020= [HW,NET] ARCnet - COM20020 chipset
437 Format:
438 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
440 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
441 Format: <io>[,<irq>]
443 com90xx= [HW,NET]
444 ARCnet - COM90xx chipset (memory-mapped buffers)
445 Format: <io>[,<irq>[,<memstart>]]
447 condev= [HW,S390] console device
448 conmode=
450 console= [KNL] Output console device and options.
452 tty<n> Use the virtual console device <n>.
454 ttyS<n>[,options]
455 ttyUSB0[,options]
456 Use the specified serial port. The options are of
457 the form "bbbbpnf", where "bbbb" is the baud rate,
458 "p" is parity ("n", "o", or "e"), "n" is number of
459 bits, and "f" is flow control ("r" for RTS or
460 omit it). Default is "9600n8".
462 See Documentation/serial-console.txt for more
463 information. See
464 Documentation/networking/netconsole.txt for an
465 alternative.
467 uart[8250],io,<addr>[,options]
468 uart[8250],mmio,<addr>[,options]
469 Start an early, polled-mode console on the 8250/16550
470 UART at the specified I/O port or MMIO address,
471 switching to the matching ttyS device later. The
472 options are the same as for ttyS, above.
474 earlycon= [KNL] Output early console device and options.
475 uart[8250],io,<addr>[,options]
476 uart[8250],mmio,<addr>[,options]
477 Start an early, polled-mode console on the 8250/16550
478 UART at the specified I/O port or MMIO address.
479 The options are the same as for ttyS, above.
481 no_console_suspend
482 [HW] Never suspend the console
483 Disable suspending of consoles during suspend and
484 hibernate operations. Once disabled, debugging
485 messages can reach various consoles while the rest
486 of the system is being put to sleep (ie, while
487 debugging driver suspend/resume hooks). This may
488 not work reliably with all consoles, but is known
489 to work with serial and VGA consoles.
491 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
492 Format:
493 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
495 crashkernel=nn[KMG]@ss[KMG]
496 [KNL] Reserve a chunk of physical memory to
497 hold a kernel to switch to with kexec on panic.
499 crashkernel=range1:size1[,range2:size2,...][@offset]
500 [KNL] Same as above, but depends on the memory
501 in the running system. The syntax of range is
502 start-[end] where start and end are both
503 a memory unit (amount[KMG]). See also
504 Documentation/kdump/kdump.txt for a example.
506 cs4232= [HW,OSS]
507 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
509 cs89x0_dma= [HW,NET]
510 Format: <dma>
512 cs89x0_media= [HW,NET]
513 Format: { rj45 | aui | bnc }
515 dasd= [HW,NET]
516 See header of drivers/s390/block/dasd_devmap.c.
518 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
519 (one device per port)
520 Format: <port#>,<type>
521 See also Documentation/input/joystick-parport.txt
523 debug [KNL] Enable kernel debugging (events log level).
525 debug_locks_verbose=
526 [KNL] verbose self-tests
527 Format=<0|1>
528 Print debugging info while doing the locking API
529 self-tests.
530 We default to 0 (no extra messages), setting it to
531 1 will print _a lot_ more information - normally
532 only useful to kernel developers.
534 decnet= [HW,NET]
535 Format: <area>[,<node>]
536 See also Documentation/networking/decnet.txt.
538 vt.default_blu= [VT]
539 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
540 Change the default blue palette of the console.
541 This is a 16-member array composed of values
542 ranging from 0-255.
544 vt.default_grn= [VT]
545 Format: <green0>,<green1>,<green2>,...,<green15>
546 Change the default green palette of the console.
547 This is a 16-member array composed of values
548 ranging from 0-255.
550 vt.default_red= [VT]
551 Format: <red0>,<red1>,<red2>,...,<red15>
552 Change the default red palette of the console.
553 This is a 16-member array composed of values
554 ranging from 0-255.
556 vt.default_utf8=
557 [VT]
558 Format=<0|1>
559 Set system-wide default UTF-8 mode for all tty's.
560 Default is 1, i.e. UTF-8 mode is enabled for all
561 newly opened terminals.
563 dhash_entries= [KNL]
564 Set number of hash buckets for dentry cache.
566 digi= [HW,SERIAL]
567 IO parameters + enable/disable command.
569 digiepca= [HW,SERIAL]
570 See drivers/char/README.epca and
571 Documentation/digiepca.txt.
573 dmasound= [HW,OSS] Sound subsystem buffers
575 dscc4.setup= [NET]
577 dtc3181e= [HW,SCSI]
579 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
580 earlyprintk=vga
581 earlyprintk=serial[,ttySn[,baudrate]]
583 Append ",keep" to not disable it when the real console
584 takes over.
586 Only vga or serial at a time, not both.
588 Currently only ttyS0 and ttyS1 are supported.
590 Interaction with the standard serial driver is not
591 very good.
593 The VGA output is eventually overwritten by the real
594 console.
596 eata= [HW,SCSI]
598 edd= [EDD]
599 Format: {"of[f]" | "sk[ipmbr]"}
600 See comment in arch/i386/boot/edd.S
602 eisa_irq_edge= [PARISC,HW]
603 See header of drivers/parisc/eisa.c.
605 elanfreq= [X86-32]
606 See comment before function elanfreq_setup() in
607 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
609 elevator= [IOSCHED]
610 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
611 See Documentation/block/as-iosched.txt and
612 Documentation/block/deadline-iosched.txt for details.
614 elfcorehdr= [X86-32, X86_64]
615 Specifies physical address of start of kernel core
616 image elf header. Generally kexec loader will
617 pass this option to capture kernel.
618 See Documentation/kdump/kdump.txt for details.
620 enforcing [SELINUX] Set initial enforcing status.
621 Format: {"0" | "1"}
622 See security/selinux/Kconfig help text.
623 0 -- permissive (log only, no denials).
624 1 -- enforcing (deny and log).
625 Default value is 0.
626 Value can be changed at runtime via /selinux/enforce.
628 es1371= [HW,OSS]
629 Format: <spdif>,[<nomix>,[<amplifier>]]
630 See also header of sound/oss/es1371.c.
632 ether= [HW,NET] Ethernet cards parameters
633 This option is obsoleted by the "netdev=" option, which
634 has equivalent usage. See its documentation for details.
636 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
637 Format: <io>[,<irq>]
639 failslab=
640 fail_page_alloc=
641 fail_make_request=[KNL]
642 General fault injection mechanism.
643 Format: <interval>,<probability>,<space>,<times>
644 See also /Documentation/fault-injection/.
646 fd_mcs= [HW,SCSI]
647 See header of drivers/scsi/fd_mcs.c.
649 fdomain= [HW,SCSI]
650 See header of drivers/scsi/fdomain.c.
652 floppy= [HW]
653 See Documentation/floppy.txt.
655 gamecon.map[2|3]=
656 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
657 support via parallel port (up to 5 devices per port)
658 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
659 See also Documentation/input/joystick-parport.txt
661 gamma= [HW,DRM]
663 gdth= [HW,SCSI]
664 See header of drivers/scsi/gdth.c.
666 gpt [EFI] Forces disk with valid GPT signature but
667 invalid Protective MBR to be treated as GPT.
669 gvp11= [HW,SCSI]
671 hashdist= [KNL,NUMA] Large hashes allocated during boot
672 are distributed across NUMA nodes. Defaults on
673 for IA-64, off otherwise.
674 Format: 0 | 1 (for off | on)
676 hcl= [IA-64] SGI's Hardware Graph compatibility layer
678 hd= [EIDE] (E)IDE hard drive subsystem geometry
679 Format: <cyl>,<head>,<sect>
681 hd?= [HW] (E)IDE subsystem
682 hd?lun= See Documentation/ide.txt.
684 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
685 size of <nn>. This works even on boxes that have no
686 highmem otherwise. This also works to reduce highmem
687 size on bigger boxes.
689 highres= [KNL] Enable/disable high resolution timer mode.
690 Valid parameters: "on", "off"
691 Default: "on"
693 hisax= [HW,ISDN]
694 See Documentation/isdn/README.HiSax.
696 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
698 i8042.direct [HW] Put keyboard port into non-translated mode
699 i8042.dumbkbd [HW] Pretend that controller can only read data from
700 keyboard and cannot control its state
701 (Don't attempt to blink the leds)
702 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
703 i8042.nokbd [HW] Don't check/create keyboard port
704 i8042.nomux [HW] Don't check presence of an active multiplexing
705 controller
706 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
707 controllers
708 i8042.panicblink=
709 [HW] Frequency with which keyboard LEDs should blink
710 when kernel panics (default is 0.5 sec)
711 i8042.reset [HW] Reset the controller during init and cleanup
712 i8042.unlock [HW] Unlock (ignore) the keylock
714 i810= [HW,DRM]
716 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
717 indicates that the driver is running on unsupported
718 hardware.
719 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
720 does not match list of supported models.
721 i8k.power_status
722 [HW] Report power status in /proc/i8k
723 (disabled by default)
724 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
725 capability is set.
727 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
728 See Documentation/mca.txt.
730 icn= [HW,ISDN]
731 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
733 ide= [HW] (E)IDE subsystem
734 Format: ide=nodma or ide=doubler or ide=reverse
735 See Documentation/ide.txt.
737 ide?= [HW] (E)IDE subsystem
738 Format: ide?=noprobe or chipset specific parameters.
739 See Documentation/ide.txt.
741 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
742 See Documentation/ide.txt.
744 idle= [X86]
745 Format: idle=poll or idle=mwait
746 Poll forces a polling idle loop that can slightly improves the performance
747 of waking up a idle CPU, but will use a lot of power and make the system
748 run hot. Not recommended.
749 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
750 to not use it because it doesn't save as much power as a normal idle
751 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
752 as idle=poll.
754 ignore_loglevel [KNL]
755 Ignore loglevel setting - this will print /all/
756 kernel messages to the console. Useful for debugging.
758 ihash_entries= [KNL]
759 Set number of hash buckets for inode cache.
761 in2000= [HW,SCSI]
762 See header of drivers/scsi/in2000.c.
764 init= [KNL]
765 Format: <full_path>
766 Run specified binary instead of /sbin/init as init
767 process.
769 initcall_debug [KNL] Trace initcalls as they are executed. Useful
770 for working out where the kernel is dying during
771 startup.
773 initrd= [BOOT] Specify the location of the initial ramdisk
775 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
776 Format: <irq>
778 inttest= [IA64]
780 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
781 off
782 Disable intel iommu driver.
783 igfx_off [Default Off]
784 By default, gfx is mapped as normal device. If a gfx
785 device has a dedicated DMAR unit, the DMAR unit is
786 bypassed by not enabling DMAR with this option. In
787 this case, gfx device will use physical address for
788 DMA.
789 forcedac [x86_64]
790 With this option iommu will not optimize to look
791 for io virtual address below 32 bit forcing dual
792 address cycle on pci bus for cards supporting greater
793 than 32 bit addressing. The default is to look
794 for translation below 32 bit and if not available
795 then look in the higher range.
797 io7= [HW] IO7 for Marvel based alpha systems
798 See comment before marvel_specify_io7 in
799 arch/alpha/kernel/core_marvel.c.
801 ip= [IP_PNP]
802 See Documentation/nfsroot.txt.
804 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
805 See comment before ip2_setup() in
806 drivers/char/ip2/ip2base.c.
808 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
809 See header of drivers/scsi/ips.c.
811 ports= [IP_VS_FTP] IPVS ftp helper module
812 Default is 21.
813 Up to 8 (IP_VS_APP_MAX_PORTS) ports
814 may be specified.
815 Format: <port>,<port>....
817 irqfixup [HW]
818 When an interrupt is not handled search all handlers
819 for it. Intended to get systems with badly broken
820 firmware running.
822 irqpoll [HW]
823 When an interrupt is not handled search all handlers
824 for it. Also check all handlers each timer
825 interrupt. Intended to get systems with badly broken
826 firmware running.
828 isapnp= [ISAPNP]
829 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
831 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
832 Format:
833 <cpu number>,...,<cpu number>
834 or
835 <cpu number>-<cpu number> (must be a positive range in ascending order)
836 or a mixture
837 <cpu number>,...,<cpu number>-<cpu number>
838 This option can be used to specify one or more CPUs
839 to isolate from the general SMP balancing and scheduling
840 algorithms. The only way to move a process onto or off
841 an "isolated" CPU is via the CPU affinity syscalls.
842 <cpu number> begins at 0 and the maximum value is
843 "number of CPUs in system - 1".
845 This option is the preferred way to isolate CPUs. The
846 alternative -- manually setting the CPU mask of all
847 tasks in the system -- can cause problems and
848 suboptimal load balancer performance.
850 iucv= [HW,NET]
852 js= [HW,JOY] Analog joystick
853 See Documentation/input/joystick.txt.
855 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
856 specifies the amount of memory usable by the kernel
857 for non-movable allocations. The requested amount is
858 spread evenly throughout all nodes in the system. The
859 remaining memory in each node is used for Movable
860 pages. In the event, a node is too small to have both
861 kernelcore and Movable pages, kernelcore pages will
862 take priority and other nodes will have a larger number
863 of kernelcore pages. The Movable zone is used for the
864 allocation of pages that may be reclaimed or moved
865 by the page migration subsystem. This means that
866 HugeTLB pages may not be allocated from this zone.
867 Note that allocations like PTEs-from-HighMem still
868 use the HighMem zone if it exists, and the Normal
869 zone if it does not.
871 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
872 is similar to kernelcore except it specifies the
873 amount of memory used for migratable allocations.
874 If both kernelcore and movablecore is specified,
875 then kernelcore will be at *least* the specified
876 value but may be more. If movablecore on its own
877 is specified, the administrator must be careful
878 that the amount of memory usable for all allocations
879 is not too small.
881 keepinitrd [HW,ARM]
883 kstack=N [X86-32,X86-64] Print N words from the kernel stack
884 in oops dumps.
886 l2cr= [PPC]
888 lapic [X86-32,APIC] Enable the local APIC even if BIOS
889 disabled it.
891 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
892 C2 power state.
894 libata.dma= [LIBATA] DMA control
895 libata.dma=0 Disable all PATA and SATA DMA
896 libata.dma=1 PATA and SATA Disk DMA only
897 libata.dma=2 ATAPI (CDROM) DMA only
898 libata.dma=4 Compact Flash DMA only
899 Combinations also work, so libata.dma=3 enables DMA
900 for disks and CDROMs, but not CFs.
902 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
903 when set.
904 Format: <int>
906 load_ramdisk= [RAM] List of ramdisks to load from floppy
907 See Documentation/ramdisk.txt.
909 lockd.nlm_grace_period=P [NFS] Assign grace period.
910 Format: <integer>
912 lockd.nlm_tcpport=N [NFS] Assign TCP port.
913 Format: <integer>
915 lockd.nlm_timeout=T [NFS] Assign timeout value.
916 Format: <integer>
918 lockd.nlm_udpport=M [NFS] Assign UDP port.
919 Format: <integer>
921 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
922 Format: <irq>
924 loglevel= All Kernel Messages with a loglevel smaller than the
925 console loglevel will be printed to the console. It can
926 also be changed with klogd or other programs. The
927 loglevels are defined as follows:
929 0 (KERN_EMERG) system is unusable
930 1 (KERN_ALERT) action must be taken immediately
931 2 (KERN_CRIT) critical conditions
932 3 (KERN_ERR) error conditions
933 4 (KERN_WARNING) warning conditions
934 5 (KERN_NOTICE) normal but significant condition
935 6 (KERN_INFO) informational
936 7 (KERN_DEBUG) debug-level messages
938 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
939 Format: { n | nk | nM }
940 n must be a power of two. The default size
941 is set in the kernel config file.
943 logo.nologo [FB] Disables display of the built-in Linux logo.
944 This may be used to provide more screen space for
945 kernel log messages and is useful when debugging
946 kernel boot problems.
948 lp=0 [LP] Specify parallel ports to use, e.g,
949 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
950 lp=reset first parallel port). 'lp=0' disables the
951 lp=auto printer driver. 'lp=reset' (which can be
952 specified in addition to the ports) causes
953 attached printers to be reset. Using
954 lp=port1,port2,... specifies the parallel ports
955 to associate lp devices with, starting with
956 lp0. A port specification may be 'none' to skip
957 that lp device, or a parport name such as
958 'parport0'. Specifying 'lp=auto' instead of a
959 port specification list means that device IDs
960 from each port should be examined, to see if
961 an IEEE 1284-compliant printer is attached; if
962 so, the driver will manage that printer.
963 See also header of drivers/char/lp.c.
965 lpj=n [KNL]
966 Sets loops_per_jiffy to given constant, thus avoiding
967 time-consuming boot-time autodetection (up to 250 ms per
968 CPU). 0 enables autodetection (default). To determine
969 the correct value for your kernel, boot with normal
970 autodetection and see what value is printed. Note that
971 on SMP systems the preset will be applied to all CPUs,
972 which is likely to cause problems if your CPUs need
973 significantly divergent settings. An incorrect value
974 will cause delays in the kernel to be wrong, leading to
975 unpredictable I/O errors and other breakage. Although
976 unlikely, in the extreme case this might damage your
977 hardware.
979 ltpc= [NET]
980 Format: <io>,<irq>,<dma>
982 mac5380= [HW,SCSI] Format:
983 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
985 mac53c9x= [HW,SCSI] Format:
986 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
988 machvec= [IA64] Force the use of a particular machine-vector
989 (machvec) in a generic kernel.
990 Example: machvec=hpzx1_swiotlb
992 max_loop= [LOOP] Maximum number of loopback devices that can
993 be mounted
994 Format: <1-256>
996 maxcpus= [SMP] Maximum number of processors that an SMP kernel
997 should make use of. maxcpus=n : n >= 0 limits the
998 kernel to using 'n' processors. n=0 is a special case,
999 it is equivalent to "nosmp", which also disables
1000 the IO APIC.
1002 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1003 equal to this physical address is ignored.
1005 max_luns= [SCSI] Maximum number of LUNs to probe.
1006 Should be between 1 and 2^32-1.
1008 max_report_luns=
1009 [SCSI] Maximum number of LUNs received.
1010 Should be between 1 and 16384.
1012 mca-pentium [BUGS=X86-32]
1014 mcatest= [IA-64]
1016 mce [X86-32] Machine Check Exception
1018 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1020 md= [HW] RAID subsystems devices and level
1021 See Documentation/md.txt.
1023 mdacon= [MDA]
1024 Format: <first>,<last>
1025 Specifies range of consoles to be captured by the MDA.
1027 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1028 Amount of memory to be used when the kernel is not able
1029 to see the whole system memory or for test.
1030 [X86-32] Use together with memmap= to avoid physical
1031 address space collisions. Without memmap= PCI devices
1032 could be placed at addresses belonging to unused RAM.
1034 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1035 memory.
1037 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1038 E820 memory map, as specified by the user.
1039 Such memmap=exactmap lines can be constructed based on
1040 BIOS output or other requirements. See the memmap=nn@ss
1041 option description.
1043 memmap=nn[KMG]@ss[KMG]
1044 [KNL] Force usage of a specific region of memory
1045 Region of memory to be used, from ss to ss+nn.
1047 memmap=nn[KMG]#ss[KMG]
1048 [KNL,ACPI] Mark specific memory as ACPI data.
1049 Region of memory to be used, from ss to ss+nn.
1051 memmap=nn[KMG]$ss[KMG]
1052 [KNL,ACPI] Mark specific memory as reserved.
1053 Region of memory to be used, from ss to ss+nn.
1055 meye.*= [HW] Set MotionEye Camera parameters
1056 See Documentation/video4linux/meye.txt.
1058 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1059 Multi-Function General Purpose Timers on AMD Geode
1060 platforms.
1062 mga= [HW,DRM]
1064 mousedev.tap_time=
1065 [MOUSE] Maximum time between finger touching and
1066 leaving touchpad surface for touch to be considered
1067 a tap and be reported as a left button click (for
1068 touchpads working in absolute mode only).
1069 Format: <msecs>
1070 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1071 reporting absolute coordinates, such as tablets
1072 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1073 reporting absolute coordinates, such as tablets
1075 mpu401= [HW,OSS]
1076 Format: <io>,<irq>
1078 MTD_Partition= [MTD]
1079 Format: <name>,<region-number>,<size>,<offset>
1081 MTD_Region= [MTD] Format:
1082 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1084 mtdparts= [MTD]
1085 See drivers/mtd/cmdlinepart.c.
1087 mtouchusb.raw_coordinates=
1088 [HW] Make the MicroTouch USB driver use raw coordinates
1089 ('y', default) or cooked coordinates ('n')
1091 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1093 NCR_D700= [HW,SCSI]
1094 See header of drivers/scsi/NCR_D700.c.
1096 ncr5380= [HW,SCSI]
1098 ncr53c400= [HW,SCSI]
1100 ncr53c400a= [HW,SCSI]
1102 ncr53c406a= [HW,SCSI]
1104 ncr53c8xx= [HW,SCSI]
1106 netdev= [NET] Network devices parameters
1107 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1108 Note that mem_start is often overloaded to mean
1109 something different and driver-specific.
1110 This usage is only documented in each driver source
1111 file if at all.
1113 nfsaddrs= [NFS]
1114 See Documentation/nfsroot.txt.
1116 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1117 See Documentation/nfsroot.txt.
1119 nfs.callback_tcpport=
1120 [NFS] set the TCP port on which the NFSv4 callback
1121 channel should listen.
1123 nfs.idmap_cache_timeout=
1124 [NFS] set the maximum lifetime for idmapper cache
1125 entries.
1127 nfs.enable_ino64=
1128 [NFS] enable 64-bit inode numbers.
1129 If zero, the NFS client will fake up a 32-bit inode
1130 number for the readdir() and stat() syscalls instead
1131 of returning the full 64-bit number.
1132 The default is to return 64-bit inode numbers.
1134 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1135 when a NMI is triggered.
1136 Format: [state][,regs][,debounce][,die]
1138 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1140 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1141 emulation library even if a 387 maths coprocessor
1142 is present.
1144 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1145 caches in the slab allocator. Saves per-node memory,
1146 but will impact performance.
1148 noalign [KNL,ARM]
1150 noapic [SMP,APIC] Tells the kernel to not make use of any
1151 IOAPICs that may be present in the system.
1153 nobats [PPC] Do not use BATs for mapping kernel lowmem
1154 on "Classic" PPC cores.
1156 nocache [ARM]
1158 nodelayacct [KNL] Disable per-task delay accounting
1160 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1162 noexec [IA-64]
1164 noexec [X86-32,X86-64]
1165 noexec=on: enable non-executable mappings (default)
1166 noexec=off: disable nn-executable mappings
1168 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1169 register save and restore. The kernel will only save
1170 legacy floating-point registers on task switch.
1172 nohlt [BUGS=ARM]
1174 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1175 instruction doesn't work correctly and not to
1176 use it.
1178 nohalt [IA-64] Tells the kernel not to use the power saving
1179 function PAL_HALT_LIGHT when idle. This increases
1180 power-consumption. On the positive side, it reduces
1181 interrupt wake-up latency, which may improve performance
1182 in certain environments such as networked servers or
1183 real-time systems.
1185 nohz= [KNL] Boottime enable/disable dynamic ticks
1186 Valid arguments: on, off
1187 Default: on
1189 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1191 noirqdebug [X86-32] Disables the code which attempts to detect and
1192 disable unhandled interrupt sources.
1194 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1195 broken timer IRQ sources.
1197 noisapnp [ISAPNP] Disables ISA PnP code.
1199 noinitrd [RAM] Tells the kernel not to load any configured
1200 initial RAM disk.
1202 nointroute [IA-64]
1204 nojitter [IA64] Disables jitter checking for ITC timers.
1206 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1208 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1210 noltlbs [PPC] Do not use large page/tlb entries for kernel
1211 lowmem mapping on PPC40x.
1213 nomca [IA-64] Disable machine check abort handling
1215 nomce [X86-32] Machine Check Exception
1217 nomfgpt [X86-32] Disable Multi-Function General Purpose
1218 Timer usage (for AMD Geode machines).
1220 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1222 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1223 with UP alternatives
1225 noresidual [PPC] Don't use residual data on PReP machines.
1227 noresume [SWSUSP] Disables resume and restores original swap
1228 space.
1230 no-scroll [VGA] Disables scrollback.
1231 This is required for the Braillex ib80-piezo Braille
1232 reader made by F.H. Papenmeier (Germany).
1234 nosbagart [IA-64]
1236 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1238 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1239 and disable the IO APIC. legacy for "maxcpus=0".
1241 nosoftlockup [KNL] Disable the soft-lockup detector.
1243 nosync [HW,M68K] Disables sync negotiation for all devices.
1245 notsc [BUGS=X86-32] Disable Time Stamp Counter
1247 nousb [USB] Disable the USB subsystem
1249 nowb [ARM]
1251 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1252 one of ['zone', 'node', 'default'] can be specified
1253 This can be set from sysctl after boot.
1254 See Documentation/sysctl/vm.txt for details.
1256 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1258 opl3= [HW,OSS]
1259 Format: <io>
1261 oprofile.timer= [HW]
1262 Use timer interrupt instead of performance counters
1264 osst= [HW,SCSI] SCSI Tape Driver
1265 Format: <buffer_size>,<write_threshold>
1266 See also Documentation/scsi/st.txt.
1268 panic= [KNL] Kernel behaviour on panic
1269 Format: <timeout>
1271 parkbd.port= [HW] Parallel port number the keyboard adapter is
1272 connected to, default is 0.
1273 Format: <parport#>
1274 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1275 0 for XT, 1 for AT (default is AT).
1276 Format: <mode>
1278 parport= [HW,PPT] Specify parallel ports. 0 disables.
1279 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1280 Use 'auto' to force the driver to use any
1281 IRQ/DMA settings detected (the default is to
1282 ignore detected IRQ/DMA settings because of
1283 possible conflicts). You can specify the base
1284 address, IRQ, and DMA settings; IRQ and DMA
1285 should be numbers, or 'auto' (for using detected
1286 settings on that particular port), or 'nofifo'
1287 (to avoid using a FIFO even if it is detected).
1288 Parallel ports are assigned in the order they
1289 are specified on the command line, starting
1290 with parport0.
1292 parport_init_mode= [HW,PPT]
1293 Configure VIA parallel port to operate in
1294 a specific mode. This is necessary on Pegasos
1295 computer where firmware has no options for setting
1296 up parallel port mode and sets it to spp.
1297 Currently this function knows 686a and 8231 chips.
1298 Format: [spp|ps2|epp|ecp|ecpepp]
1300 pas2= [HW,OSS] Format:
1301 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1303 pas16= [HW,SCSI]
1304 See header of drivers/scsi/pas16.c.
1306 pause_on_oops=
1307 Halt all CPUs after the first oops has been printed for
1308 the specified number of seconds. This is to be used if
1309 your oopses keep scrolling off the screen.
1311 pcbit= [HW,ISDN]
1313 pcd. [PARIDE]
1314 See header of drivers/block/paride/pcd.c.
1315 See also Documentation/paride.txt.
1317 pci=option[,option...] [PCI] various PCI subsystem options:
1318 off [X86-32] don't probe for the PCI bus
1319 bios [X86-32] force use of PCI BIOS, don't access
1320 the hardware directly. Use this if your machine
1321 has a non-standard PCI host bridge.
1322 nobios [X86-32] disallow use of PCI BIOS, only direct
1323 hardware access methods are allowed. Use this
1324 if you experience crashes upon bootup and you
1325 suspect they are caused by the BIOS.
1326 conf1 [X86-32] Force use of PCI Configuration
1327 Mechanism 1.
1328 conf2 [X86-32] Force use of PCI Configuration
1329 Mechanism 2.
1330 noaer [PCIE] If the PCIEAER kernel config parameter is
1331 enabled, this kernel boot option can be used to
1332 disable the use of PCIE advanced error reporting.
1333 nodomains [PCI] Disable support for multiple PCI
1334 root domains (aka PCI segments, in ACPI-speak).
1335 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1336 Configuration
1337 nomsi [MSI] If the PCI_MSI kernel config parameter is
1338 enabled, this kernel boot option can be used to
1339 disable the use of MSI interrupts system-wide.
1340 nosort [X86-32] Don't sort PCI devices according to
1341 order given by the PCI BIOS. This sorting is
1342 done to get a device order compatible with
1343 older kernels.
1344 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1345 routing table. These calls are known to be buggy
1346 on several machines and they hang the machine
1347 when used, but on other computers it's the only
1348 way to get the interrupt routing table. Try
1349 this option if the kernel is unable to allocate
1350 IRQs or discover secondary PCI buses on your
1351 motherboard.
1352 rom [X86-32] Assign address space to expansion ROMs.
1353 Use with caution as certain devices share
1354 address decoders between ROMs and other
1355 resources.
1356 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1357 assigned automatically to PCI devices. You can
1358 make the kernel exclude IRQs of your ISA cards
1359 this way.
1360 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1361 of the PIRQ table (normally generated
1362 by the BIOS) if it is outside the
1363 F0000h-100000h range.
1364 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1365 useful if the kernel is unable to find your
1366 secondary buses and you want to tell it
1367 explicitly which ones they are.
1368 assign-busses [X86-32] Always assign all PCI bus
1369 numbers ourselves, overriding
1370 whatever the firmware may have done.
1371 usepirqmask [X86-32] Honor the possible IRQ mask stored
1372 in the BIOS $PIR table. This is needed on
1373 some systems with broken BIOSes, notably
1374 some HP Pavilion N5400 and Omnibook XE3
1375 notebooks. This will have no effect if ACPI
1376 IRQ routing is enabled.
1377 noacpi [X86-32] Do not use ACPI for IRQ routing
1378 or for PCI scanning.
1379 use_crs [X86-32] Use _CRS for PCI resource
1380 allocation.
1381 routeirq Do IRQ routing for all PCI devices.
1382 This is normally done in pci_enable_device(),
1383 so this option is a temporary workaround
1384 for broken drivers that don't call it.
1385 firmware [ARM] Do not re-enumerate the bus but instead
1386 just use the configuration from the
1387 bootloader. This is currently used on
1388 IXP2000 systems where the bus has to be
1389 configured a certain way for adjunct CPUs.
1390 noearly [X86] Don't do any early type 1 scanning.
1391 This might help on some broken boards which
1392 machine check when some devices' config space
1393 is read. But various workarounds are disabled
1394 and some IOMMU drivers will not work.
1395 bfsort Sort PCI devices into breadth-first order.
1396 This sorting is done to get a device
1397 order compatible with older (<= 2.4) kernels.
1398 nobfsort Don't sort PCI devices into breadth-first order.
1399 cbiosize=nn[KMG] The fixed amount of bus space which is
1400 reserved for the CardBus bridge's IO window.
1401 The default value is 256 bytes.
1402 cbmemsize=nn[KMG] The fixed amount of bus space which is
1403 reserved for the CardBus bridge's memory
1404 window. The default value is 64 megabytes.
1406 pcmv= [HW,PCMCIA] BadgePAD 4
1408 pd. [PARIDE]
1409 See Documentation/paride.txt.
1411 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1412 boot time.
1413 Format: { 0 | 1 }
1414 See arch/parisc/kernel/pdc_chassis.c
1416 pf. [PARIDE]
1417 See Documentation/paride.txt.
1419 pg. [PARIDE]
1420 See Documentation/paride.txt.
1422 pirq= [SMP,APIC] Manual mp-table setup
1423 See Documentation/i386/IO-APIC.txt.
1425 plip= [PPT,NET] Parallel port network link
1426 Format: { parport<nr> | timid | 0 }
1427 See also Documentation/parport.txt.
1429 pnpacpi= [ACPI]
1430 { off }
1432 pnpbios= [ISAPNP]
1433 { on | off | curr | res | no-curr | no-res }
1435 pnp_reserve_irq=
1436 [ISAPNP] Exclude IRQs for the autoconfiguration
1438 pnp_reserve_dma=
1439 [ISAPNP] Exclude DMAs for the autoconfiguration
1441 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1442 Ranges are in pairs (I/O port base and size).
1444 pnp_reserve_mem=
1445 [ISAPNP] Exclude memory regions for the
1446 autoconfiguration.
1447 Ranges are in pairs (memory base and size).
1449 print-fatal-signals=
1450 [KNL] debug: print fatal signals
1451 print-fatal-signals=1: print segfault info to
1452 the kernel console.
1453 default: off.
1455 printk.time= Show timing data prefixed to each printk message line
1456 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1458 profile= [KNL] Enable kernel profiling via /proc/profile
1459 Format: [schedule,]<number>
1460 Param: "schedule" - profile schedule points.
1461 Param: <number> - step/bucket size as a power of 2 for
1462 statistical time based profiling.
1463 Param: "sleep" - profile D-state sleeping (millisecs).
1464 Requires CONFIG_SCHEDSTATS
1465 Param: "kvm" - profile VM exits.
1467 processor.max_cstate= [HW,ACPI]
1468 Limit processor to maximum C-state
1469 max_cstate=9 overrides any DMI blacklist limit.
1471 processor.nocst [HW,ACPI]
1472 Ignore the _CST method to determine C-states,
1473 instead using the legacy FADT method
1475 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1476 before loading.
1477 See Documentation/ramdisk.txt.
1479 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1480 probe for; one of (bare|imps|exps|lifebook|any).
1481 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1482 per second.
1483 psmouse.resetafter= [HW,MOUSE]
1484 Try to reset the device after so many bad packets
1485 (0 = never).
1486 psmouse.resolution=
1487 [HW,MOUSE] Set desired mouse resolution, in dpi.
1488 psmouse.smartscroll=
1489 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1490 0 = disabled, 1 = enabled (default).
1492 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1493 Format:
1494 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1496 pt. [PARIDE]
1497 See Documentation/paride.txt.
1499 pty.legacy_count=
1500 [KNL] Number of legacy pty's. Overwrites compiled-in
1501 default number.
1503 quiet [KNL] Disable most log messages
1505 r128= [HW,DRM]
1507 raid= [HW,RAID]
1508 See Documentation/md.txt.
1510 ramdisk_blocksize= [RAM]
1511 See Documentation/ramdisk.txt.
1513 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1514 See Documentation/ramdisk.txt.
1516 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1517 RCU callbacks to process in one batch.
1519 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1520 RCU callbacks over which batch limiting is disabled.
1522 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1523 RCU callbacks below which batch limiting is re-enabled.
1525 rdinit= [KNL]
1526 Format: <full_path>
1527 Run specified binary instead of /init from the ramdisk,
1528 used for early userspace startup. See initrd.
1530 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1531 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1532 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1534 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1536 reservetop= [X86-32]
1537 Format: nn[KMG]
1538 Reserves a hole at the top of the kernel virtual
1539 address space.
1541 reset_devices [KNL] Force drivers to reset the underlying device
1542 during initialization.
1544 resume= [SWSUSP]
1545 Specify the partition device for software suspend
1547 resume_offset= [SWSUSP]
1548 Specify the offset from the beginning of the partition
1549 given by "resume=" at which the swap header is located,
1550 in <PAGE_SIZE> units (needed only for swap files).
1551 See Documentation/power/swsusp-and-swap-files.txt
1553 retain_initrd [RAM] Keep initrd memory after extraction
1555 rhash_entries= [KNL,NET]
1556 Set number of hash buckets for route cache
1558 riscom8= [HW,SERIAL]
1559 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1561 ro [KNL] Mount root device read-only on boot
1563 root= [KNL] Root filesystem
1565 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1566 mount the root filesystem
1568 rootflags= [KNL] Set root filesystem mount option string
1570 rootfstype= [KNL] Set root filesystem type
1572 rootwait [KNL] Wait (indefinitely) for root device to show up.
1573 Useful for devices that are detected asynchronously
1574 (e.g. USB and MMC devices).
1576 root_plug.vendor_id=
1577 [ROOTPLUG] Override the default vendor ID
1579 root_plug.product_id=
1580 [ROOTPLUG] Override the default product ID
1582 root_plug.debug=
1583 [ROOTPLUG] Enable debugging output
1585 rw [KNL] Mount root device read-write on boot
1587 S [KNL] Run init in single mode
1589 sa1100ir [NET]
1590 See drivers/net/irda/sa1100_ir.c.
1592 sbni= [NET] Granch SBNI12 leased line adapter
1594 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1595 Format: <io>[,<timeout>[,<isapnp>]]
1597 scsi_debug_*= [SCSI]
1598 See drivers/scsi/scsi_debug.c.
1600 scsi_default_dev_flags=
1601 [SCSI] SCSI default device flags
1602 Format: <integer>
1604 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1605 Format: <vendor>:<model>:<flags>
1606 (flags are integer value)
1608 scsi_logging_level= [SCSI] a bit mask of logging levels
1609 See drivers/scsi/scsi_logging.h for bits. Also
1610 settable via sysctl at dev.scsi.logging_level
1611 (/proc/sys/dev/scsi/logging_level).
1612 There is also a nice 'scsi_logging_level' script in the
1613 S390-tools package, available for download at
1614 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1616 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1617 discovered. async scans them in kernel threads,
1618 allowing boot to proceed. none ignores them, expecting
1619 user space to do the scan.
1621 selinux [SELINUX] Disable or enable SELinux at boot time.
1622 Format: { "0" | "1" }
1623 See security/selinux/Kconfig help text.
1624 0 -- disable.
1625 1 -- enable.
1626 Default value is set via kernel config option.
1627 If enabled at boot time, /selinux/disable can be used
1628 later to disable prior to initial policy load.
1630 selinux_compat_net =
1631 [SELINUX] Set initial selinux_compat_net flag value.
1632 Format: { "0" | "1" }
1633 0 -- use new secmark-based packet controls
1634 1 -- use legacy packet controls
1635 Default value is 0 (preferred).
1636 Value can be changed at runtime via
1637 /selinux/compat_net.
1639 serialnumber [BUGS=X86-32]
1641 shapers= [NET]
1642 Maximal number of shapers.
1644 sim710= [SCSI,HW]
1645 See header of drivers/scsi/sim710.c.
1647 simeth= [IA-64]
1648 simscsi=
1650 slram= [HW,MTD]
1652 slub_debug[=options[,slabs]] [MM, SLUB]
1653 Enabling slub_debug allows one to determine the
1654 culprit if slab objects become corrupted. Enabling
1655 slub_debug can create guard zones around objects and
1656 may poison objects when not in use. Also tracks the
1657 last alloc / free. For more information see
1658 Documentation/vm/slub.txt.
1660 slub_max_order= [MM, SLUB]
1661 Determines the maximum allowed order for slabs.
1662 A high setting may cause OOMs due to memory
1663 fragmentation. For more information see
1664 Documentation/vm/slub.txt.
1666 slub_min_objects= [MM, SLUB]
1667 The minimum number of objects per slab. SLUB will
1668 increase the slab order up to slub_max_order to
1669 generate a sufficiently large slab able to contain
1670 the number of objects indicated. The higher the number
1671 of objects the smaller the overhead of tracking slabs
1672 and the less frequently locks need to be acquired.
1673 For more information see Documentation/vm/slub.txt.
1675 slub_min_order= [MM, SLUB]
1676 Determines the mininum page order for slabs. Must be
1677 lower than slub_max_order.
1678 For more information see Documentation/vm/slub.txt.
1680 slub_nomerge [MM, SLUB]
1681 Disable merging of slabs with similar size. May be
1682 necessary if there is some reason to distinguish
1683 allocs to different slabs. Debug options disable
1684 merging on their own.
1685 For more information see Documentation/vm/slub.txt.
1687 smart2= [HW]
1688 Format: <io1>[,<io2>[,...,<io8>]]
1690 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1691 attempt to substitute SMP alternatives once at boot.
1693 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1694 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1695 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1696 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1697 smsc-ircc2.ircc_irq= [HW] IRQ line
1698 smsc-ircc2.ircc_dma= [HW] DMA channel
1699 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1700 0: Toshiba Satellite 1800 (GP data pin select)
1701 1: Fast pin select (default)
1702 2: ATC IRMode
1704 snd-ad1816a= [HW,ALSA]
1706 snd-ad1848= [HW,ALSA]
1708 snd-ali5451= [HW,ALSA]
1710 snd-als100= [HW,ALSA]
1712 snd-als4000= [HW,ALSA]
1714 snd-azt2320= [HW,ALSA]
1716 snd-cmi8330= [HW,ALSA]
1718 snd-cmipci= [HW,ALSA]
1720 snd-cs4231= [HW,ALSA]
1722 snd-cs4232= [HW,ALSA]
1724 snd-cs4236= [HW,ALSA]
1726 snd-cs4281= [HW,ALSA]
1728 snd-cs46xx= [HW,ALSA]
1730 snd-dt019x= [HW,ALSA]
1732 snd-dummy= [HW,ALSA]
1734 snd-emu10k1= [HW,ALSA]
1736 snd-ens1370= [HW,ALSA]
1738 snd-ens1371= [HW,ALSA]
1740 snd-es968= [HW,ALSA]
1742 snd-es1688= [HW,ALSA]
1744 snd-es18xx= [HW,ALSA]
1746 snd-es1938= [HW,ALSA]
1748 snd-es1968= [HW,ALSA]
1750 snd-fm801= [HW,ALSA]
1752 snd-gusclassic= [HW,ALSA]
1754 snd-gusextreme= [HW,ALSA]
1756 snd-gusmax= [HW,ALSA]
1758 snd-hdsp= [HW,ALSA]
1760 snd-ice1712= [HW,ALSA]
1762 snd-intel8x0= [HW,ALSA]
1764 snd-interwave= [HW,ALSA]
1766 snd-interwave-stb=
1767 [HW,ALSA]
1769 snd-korg1212= [HW,ALSA]
1771 snd-maestro3= [HW,ALSA]
1773 snd-mpu401= [HW,ALSA]
1775 snd-mtpav= [HW,ALSA]
1777 snd-nm256= [HW,ALSA]
1779 snd-opl3sa2= [HW,ALSA]
1781 snd-opti92x-ad1848=
1782 [HW,ALSA]
1784 snd-opti92x-cs4231=
1785 [HW,ALSA]
1787 snd-opti93x= [HW,ALSA]
1789 snd-pmac= [HW,ALSA]
1791 snd-rme32= [HW,ALSA]
1793 snd-rme96= [HW,ALSA]
1795 snd-rme9652= [HW,ALSA]
1797 snd-sb8= [HW,ALSA]
1799 snd-sb16= [HW,ALSA]
1801 snd-sbawe= [HW,ALSA]
1803 snd-serial= [HW,ALSA]
1805 snd-sgalaxy= [HW,ALSA]
1807 snd-sonicvibes= [HW,ALSA]
1809 snd-sun-amd7930=
1810 [HW,ALSA]
1812 snd-sun-cs4231= [HW,ALSA]
1814 snd-trident= [HW,ALSA]
1816 snd-usb-audio= [HW,ALSA,USB]
1818 snd-via82xx= [HW,ALSA]
1820 snd-virmidi= [HW,ALSA]
1822 snd-wavefront= [HW,ALSA]
1824 snd-ymfpci= [HW,ALSA]
1826 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1827 See Documentation/sonypi.txt
1829 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1830 See Documentation/specialix.txt.
1832 spia_io_base= [HW,MTD]
1833 spia_fio_base=
1834 spia_pedr=
1835 spia_peddr=
1837 sscape= [HW,OSS]
1838 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1840 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1841 See Documentation/scsi/st.txt.
1843 st0x= [HW,SCSI]
1844 See header of drivers/scsi/seagate.c.
1846 sti= [PARISC,HW]
1847 Format: <num>
1848 Set the STI (builtin display/keyboard on the HP-PARISC
1849 machines) console (graphic card) which should be used
1850 as the initial boot-console.
1851 See also comment in drivers/video/console/sticore.c.
1853 sti_font= [HW]
1854 See comment in drivers/video/console/sticore.c.
1856 stifb= [HW]
1857 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1859 sunrpc.pool_mode=
1860 [NFS]
1861 Control how the NFS server code allocates CPUs to
1862 service thread pools. Depending on how many NICs
1863 you have and where their interrupts are bound, this
1864 option will affect which CPUs will do NFS serving.
1865 Note: this parameter cannot be changed while the
1866 NFS server is running.
1868 auto the server chooses an appropriate mode
1869 automatically using heuristics
1870 global a single global pool contains all CPUs
1871 percpu one pool for each CPU
1872 pernode one pool for each NUMA node (equivalent
1873 to global on non-NUMA machines)
1875 swiotlb= [IA-64] Number of I/O TLB slabs
1877 switches= [HW,M68k]
1879 sym53c416= [HW,SCSI]
1880 See header of drivers/scsi/sym53c416.c.
1882 sysrq_always_enabled
1883 [KNL]
1884 Ignore sysrq setting - this boot parameter will
1885 neutralize any effect of /proc/sys/kernel/sysrq.
1886 Useful for debugging.
1888 t128= [HW,SCSI]
1889 See header of drivers/scsi/t128.c.
1891 tdfx= [HW,DRM]
1893 thash_entries= [KNL,NET]
1894 Set number of hash buckets for TCP connection
1896 thermal.act= [HW,ACPI]
1897 -1: disable all active trip points in all thermal zones
1898 <degrees C>: override all lowest active trip points
1900 thermal.crt= [HW,ACPI]
1901 -1: disable all critical trip points in all thermal zones
1902 <degrees C>: lower all critical trip points
1904 thermal.nocrt= [HW,ACPI]
1905 Set to disable actions on ACPI thermal zone
1906 critical and hot trip points.
1908 thermal.off= [HW,ACPI]
1909 1: disable ACPI thermal control
1911 thermal.psv= [HW,ACPI]
1912 -1: disable all passive trip points
1913 <degrees C>: override all passive trip points to this value
1915 thermal.tzp= [HW,ACPI]
1916 Specify global default ACPI thermal zone polling rate
1917 <deci-seconds>: poll all this frequency
1918 0: no polling (default)
1920 time Show timing data prefixed to each printk message line
1921 [deprecated, see 'printk.time']
1923 tipar.timeout= [HW,PPT]
1924 Set communications timeout in tenths of a second
1925 (default 15).
1927 tipar.delay= [HW,PPT]
1928 Set inter-bit delay in microseconds (default 10).
1930 tmc8xx= [HW,SCSI]
1931 See header of drivers/scsi/seagate.c.
1933 tmscsim= [HW,SCSI]
1934 See comment before function dc390_setup() in
1935 drivers/scsi/tmscsim.c.
1937 tp720= [HW,PS2]
1939 trix= [HW,OSS] MediaTrix AudioTrix Pro
1940 Format:
1941 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1943 turbografx.map[2|3]= [HW,JOY]
1944 TurboGraFX parallel port interface
1945 Format:
1946 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1947 See also Documentation/input/joystick-parport.txt
1949 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1950 See header of drivers/scsi/u14-34f.c.
1952 uart401= [HW,OSS]
1953 Format: <io>,<irq>
1955 uart6850= [HW,OSS]
1956 Format: <io>,<irq>
1958 uhci-hcd.ignore_oc=
1959 [USB] Ignore overcurrent events (default N).
1960 Some badly-designed motherboards generate lots of
1961 bogus events, for ports that aren't wired to
1962 anything. Set this parameter to avoid log spamming.
1963 Note that genuine overcurrent events won't be
1964 reported either.
1966 usbcore.autosuspend=
1967 [USB] The autosuspend time delay (in seconds) used
1968 for newly-detected USB devices (default 2). This
1969 is the time required before an idle device will be
1970 autosuspended. Devices for which the delay is set
1971 to a negative value won't be autosuspended at all.
1973 usbhid.mousepoll=
1974 [USBHID] The interval which mice are to be polled at.
1976 vdso= [X86-32,SH,x86-64]
1977 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1978 vdso=1: enable VDSO (default)
1979 vdso=0: disable VDSO mapping
1981 vector= [IA-64,SMP]
1982 vector=percpu: enable percpu vector domain
1984 video= [FB] Frame buffer configuration
1985 See Documentation/fb/modedb.txt.
1987 vga= [BOOT,X86-32] Select a particular video mode
1988 See Documentation/i386/boot.txt and
1989 Documentation/svga.txt.
1990 Use vga=ask for menu.
1991 This is actually a boot loader parameter; the value is
1992 passed to the kernel using a special protocol.
1994 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1995 size of <nn>. This can be used to increase the
1996 minimum size (128MB on x86). It can also be used to
1997 decrease the size and leave more room for directly
1998 mapped kernel RAM.
2000 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2001 Format: <command>
2003 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2004 Format: <command>
2006 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2007 Format: <command>
2009 waveartist= [HW,OSS]
2010 Format: <io>,<irq>,<dma>,<dma2>
2012 wd33c93= [HW,SCSI]
2013 See header of drivers/scsi/wd33c93.c.
2015 wd7000= [HW,SCSI]
2016 See header of drivers/scsi/wd7000.c.
2018 wdt= [WDT] Watchdog
2019 See Documentation/watchdog/wdt.txt.
2021 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2022 xd_geo= See header of drivers/block/xd.c.
2024 xirc2ps_cs= [NET,PCMCIA]
2025 Format:
2026 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2028 norandmaps Don't use address space randomization
2029 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2031 ______________________________________________________________________
2033 TODO:
2035 Add documentation for ALSA options.
2036 Add more DRM drivers.