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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 chandev= [HW,NET] Generic channel device initialisation
375 checkreqprot [SELINUX] Set initial checkreqprot flag value.
376 Format: { "0" | "1" }
377 See security/selinux/Kconfig help text.
378 0 -- check protection applied by kernel (includes
379 any implied execute protection).
380 1 -- check protection requested by application.
381 Default value is set via a kernel config option.
382 Value can be changed at runtime via
383 /selinux/checkreqprot.
385 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
386 [Deprecated]
387 Forces specified clocksource (if available) to be used
388 when calculating gettimeofday(). If specified
389 clocksource is not available, it defaults to PIT.
390 Format: { pit | tsc | cyclone | pmtmr }
392 clocksource= [GENERIC_TIME] Override the default clocksource
393 Format: <string>
394 Override the default clocksource and use the clocksource
395 with the name specified.
396 Some clocksource names to choose from, depending on
397 the platform:
398 [all] jiffies (this is the base, fallback clocksource)
399 [ACPI] acpi_pm
400 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
401 pxa_timer,timer3,32k_counter,timer0_1
402 [AVR32] avr32
403 [X86-32] pit,hpet,tsc,vmi-timer;
404 scx200_hrt on Geode; cyclone on IBM x440
405 [MIPS] MIPS
406 [PARISC] cr16
407 [S390] tod
408 [SH] SuperH
409 [SPARC64] tick
410 [X86-64] hpet,tsc
412 code_bytes [IA32] How many bytes of object code to print in an
413 oops report.
414 Range: 0 - 8192
415 Default: 64
417 disable_8254_timer
418 enable_8254_timer
419 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
420 over the 8254 in addition to over the IO-APIC. The
421 kernel tries to set a sensible default.
423 hpet= [X86-32,HPET] option to control HPET usage
424 Format: { enable (default) | disable | force }
425 disable: disable HPET and use PIT instead
426 force: allow force enabled of undocumented chips (ICH4,
427 VIA, nVidia)
429 com20020= [HW,NET] ARCnet - COM20020 chipset
430 Format:
431 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
433 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
434 Format: <io>[,<irq>]
436 com90xx= [HW,NET]
437 ARCnet - COM90xx chipset (memory-mapped buffers)
438 Format: <io>[,<irq>[,<memstart>]]
440 condev= [HW,S390] console device
441 conmode=
443 console= [KNL] Output console device and options.
445 tty<n> Use the virtual console device <n>.
447 ttyS<n>[,options]
448 ttyUSB0[,options]
449 Use the specified serial port. The options are of
450 the form "bbbbpnf", where "bbbb" is the baud rate,
451 "p" is parity ("n", "o", or "e"), "n" is number of
452 bits, and "f" is flow control ("r" for RTS or
453 omit it). Default is "9600n8".
455 See Documentation/serial-console.txt for more
456 information. See
457 Documentation/networking/netconsole.txt for an
458 alternative.
460 uart[8250],io,<addr>[,options]
461 uart[8250],mmio,<addr>[,options]
462 Start an early, polled-mode console on the 8250/16550
463 UART at the specified I/O port or MMIO address,
464 switching to the matching ttyS device later. The
465 options are the same as for ttyS, above.
467 earlycon= [KNL] Output early console device and options.
468 uart[8250],io,<addr>[,options]
469 uart[8250],mmio,<addr>[,options]
470 Start an early, polled-mode console on the 8250/16550
471 UART at the specified I/O port or MMIO address.
472 The options are the same as for ttyS, above.
474 no_console_suspend
475 [HW] Never suspend the console
476 Disable suspending of consoles during suspend and
477 hibernate operations. Once disabled, debugging
478 messages can reach various consoles while the rest
479 of the system is being put to sleep (ie, while
480 debugging driver suspend/resume hooks). This may
481 not work reliably with all consoles, but is known
482 to work with serial and VGA consoles.
484 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
485 Format:
486 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
488 crashkernel=nn[KMG]@ss[KMG]
489 [KNL] Reserve a chunk of physical memory to
490 hold a kernel to switch to with kexec on panic.
492 crashkernel=range1:size1[,range2:size2,...][@offset]
493 [KNL] Same as above, but depends on the memory
494 in the running system. The syntax of range is
495 start-[end] where start and end are both
496 a memory unit (amount[KMG]). See also
497 Documentation/kdump/kdump.txt for a example.
499 cs4232= [HW,OSS]
500 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
502 cs89x0_dma= [HW,NET]
503 Format: <dma>
505 cs89x0_media= [HW,NET]
506 Format: { rj45 | aui | bnc }
508 dasd= [HW,NET]
509 See header of drivers/s390/block/dasd_devmap.c.
511 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
512 (one device per port)
513 Format: <port#>,<type>
514 See also Documentation/input/joystick-parport.txt
516 debug [KNL] Enable kernel debugging (events log level).
518 debug_locks_verbose=
519 [KNL] verbose self-tests
520 Format=<0|1>
521 Print debugging info while doing the locking API
522 self-tests.
523 We default to 0 (no extra messages), setting it to
524 1 will print _a lot_ more information - normally
525 only useful to kernel developers.
527 decnet= [HW,NET]
528 Format: <area>[,<node>]
529 See also Documentation/networking/decnet.txt.
531 vt.default_blu= [VT]
532 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
533 Change the default blue palette of the console.
534 This is a 16-member array composed of values
535 ranging from 0-255.
537 vt.default_grn= [VT]
538 Format: <green0>,<green1>,<green2>,...,<green15>
539 Change the default green palette of the console.
540 This is a 16-member array composed of values
541 ranging from 0-255.
543 vt.default_red= [VT]
544 Format: <red0>,<red1>,<red2>,...,<red15>
545 Change the default red palette of the console.
546 This is a 16-member array composed of values
547 ranging from 0-255.
549 vt.default_utf8=
550 [VT]
551 Format=<0|1>
552 Set system-wide default UTF-8 mode for all tty's.
553 Default is 1, i.e. UTF-8 mode is enabled for all
554 newly opened terminals.
556 dhash_entries= [KNL]
557 Set number of hash buckets for dentry cache.
559 digi= [HW,SERIAL]
560 IO parameters + enable/disable command.
562 digiepca= [HW,SERIAL]
563 See drivers/char/README.epca and
564 Documentation/digiepca.txt.
566 dmasound= [HW,OSS] Sound subsystem buffers
568 dscc4.setup= [NET]
570 dtc3181e= [HW,SCSI]
572 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
573 earlyprintk=vga
574 earlyprintk=serial[,ttySn[,baudrate]]
576 Append ",keep" to not disable it when the real console
577 takes over.
579 Only vga or serial at a time, not both.
581 Currently only ttyS0 and ttyS1 are supported.
583 Interaction with the standard serial driver is not
584 very good.
586 The VGA output is eventually overwritten by the real
587 console.
589 eata= [HW,SCSI]
591 edd= [EDD]
592 Format: {"of[f]" | "sk[ipmbr]"}
593 See comment in arch/i386/boot/edd.S
595 eisa_irq_edge= [PARISC,HW]
596 See header of drivers/parisc/eisa.c.
598 elanfreq= [X86-32]
599 See comment before function elanfreq_setup() in
600 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
602 elevator= [IOSCHED]
603 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
604 See Documentation/block/as-iosched.txt and
605 Documentation/block/deadline-iosched.txt for details.
607 elfcorehdr= [X86-32, X86_64]
608 Specifies physical address of start of kernel core
609 image elf header. Generally kexec loader will
610 pass this option to capture kernel.
611 See Documentation/kdump/kdump.txt for details.
613 enforcing [SELINUX] Set initial enforcing status.
614 Format: {"0" | "1"}
615 See security/selinux/Kconfig help text.
616 0 -- permissive (log only, no denials).
617 1 -- enforcing (deny and log).
618 Default value is 0.
619 Value can be changed at runtime via /selinux/enforce.
621 es1371= [HW,OSS]
622 Format: <spdif>,[<nomix>,[<amplifier>]]
623 See also header of sound/oss/es1371.c.
625 ether= [HW,NET] Ethernet cards parameters
626 This option is obsoleted by the "netdev=" option, which
627 has equivalent usage. See its documentation for details.
629 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
630 Format: <io>[,<irq>]
632 failslab=
633 fail_page_alloc=
634 fail_make_request=[KNL]
635 General fault injection mechanism.
636 Format: <interval>,<probability>,<space>,<times>
637 See also /Documentation/fault-injection/.
639 fd_mcs= [HW,SCSI]
640 See header of drivers/scsi/fd_mcs.c.
642 fdomain= [HW,SCSI]
643 See header of drivers/scsi/fdomain.c.
645 floppy= [HW]
646 See Documentation/floppy.txt.
648 gamecon.map[2|3]=
649 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
650 support via parallel port (up to 5 devices per port)
651 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
652 See also Documentation/input/joystick-parport.txt
654 gamma= [HW,DRM]
656 gdth= [HW,SCSI]
657 See header of drivers/scsi/gdth.c.
659 gpt [EFI] Forces disk with valid GPT signature but
660 invalid Protective MBR to be treated as GPT.
662 gvp11= [HW,SCSI]
664 hashdist= [KNL,NUMA] Large hashes allocated during boot
665 are distributed across NUMA nodes. Defaults on
666 for IA-64, off otherwise.
667 Format: 0 | 1 (for off | on)
669 hcl= [IA-64] SGI's Hardware Graph compatibility layer
671 hd= [EIDE] (E)IDE hard drive subsystem geometry
672 Format: <cyl>,<head>,<sect>
674 hd?= [HW] (E)IDE subsystem
675 hd?lun= See Documentation/ide.txt.
677 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
678 size of <nn>. This works even on boxes that have no
679 highmem otherwise. This also works to reduce highmem
680 size on bigger boxes.
682 highres= [KNL] Enable/disable high resolution timer mode.
683 Valid parameters: "on", "off"
684 Default: "on"
686 hisax= [HW,ISDN]
687 See Documentation/isdn/README.HiSax.
689 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
691 i8042.direct [HW] Put keyboard port into non-translated mode
692 i8042.dumbkbd [HW] Pretend that controller can only read data from
693 keyboard and cannot control its state
694 (Don't attempt to blink the leds)
695 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
696 i8042.nokbd [HW] Don't check/create keyboard port
697 i8042.nomux [HW] Don't check presence of an active multiplexing
698 controller
699 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
700 controllers
701 i8042.panicblink=
702 [HW] Frequency with which keyboard LEDs should blink
703 when kernel panics (default is 0.5 sec)
704 i8042.reset [HW] Reset the controller during init and cleanup
705 i8042.unlock [HW] Unlock (ignore) the keylock
707 i810= [HW,DRM]
709 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
710 indicates that the driver is running on unsupported
711 hardware.
712 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
713 does not match list of supported models.
714 i8k.power_status
715 [HW] Report power status in /proc/i8k
716 (disabled by default)
717 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
718 capability is set.
720 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
721 See Documentation/mca.txt.
723 icn= [HW,ISDN]
724 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
726 ide= [HW] (E)IDE subsystem
727 Format: ide=nodma or ide=doubler or ide=reverse
728 See Documentation/ide.txt.
730 ide?= [HW] (E)IDE subsystem
731 Format: ide?=noprobe or chipset specific parameters.
732 See Documentation/ide.txt.
734 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
735 See Documentation/ide.txt.
737 idle= [X86]
738 Format: idle=poll or idle=mwait
739 Poll forces a polling idle loop that can slightly improves the performance
740 of waking up a idle CPU, but will use a lot of power and make the system
741 run hot. Not recommended.
742 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
743 to not use it because it doesn't save as much power as a normal idle
744 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
745 as idle=poll.
747 ignore_loglevel [KNL]
748 Ignore loglevel setting - this will print /all/
749 kernel messages to the console. Useful for debugging.
751 ihash_entries= [KNL]
752 Set number of hash buckets for inode cache.
754 in2000= [HW,SCSI]
755 See header of drivers/scsi/in2000.c.
757 init= [KNL]
758 Format: <full_path>
759 Run specified binary instead of /sbin/init as init
760 process.
762 initcall_debug [KNL] Trace initcalls as they are executed. Useful
763 for working out where the kernel is dying during
764 startup.
766 initrd= [BOOT] Specify the location of the initial ramdisk
768 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
769 Format: <irq>
771 inttest= [IA64]
773 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
774 off
775 Disable intel iommu driver.
776 igfx_off [Default Off]
777 By default, gfx is mapped as normal device. If a gfx
778 device has a dedicated DMAR unit, the DMAR unit is
779 bypassed by not enabling DMAR with this option. In
780 this case, gfx device will use physical address for
781 DMA.
782 forcedac [x86_64]
783 With this option iommu will not optimize to look
784 for io virtual address below 32 bit forcing dual
785 address cycle on pci bus for cards supporting greater
786 than 32 bit addressing. The default is to look
787 for translation below 32 bit and if not available
788 then look in the higher range.
790 io7= [HW] IO7 for Marvel based alpha systems
791 See comment before marvel_specify_io7 in
792 arch/alpha/kernel/core_marvel.c.
794 ip= [IP_PNP]
795 See Documentation/nfsroot.txt.
797 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
798 See comment before ip2_setup() in
799 drivers/char/ip2/ip2base.c.
801 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
802 See header of drivers/scsi/ips.c.
804 ports= [IP_VS_FTP] IPVS ftp helper module
805 Default is 21.
806 Up to 8 (IP_VS_APP_MAX_PORTS) ports
807 may be specified.
808 Format: <port>,<port>....
810 irqfixup [HW]
811 When an interrupt is not handled search all handlers
812 for it. Intended to get systems with badly broken
813 firmware running.
815 irqpoll [HW]
816 When an interrupt is not handled search all handlers
817 for it. Also check all handlers each timer
818 interrupt. Intended to get systems with badly broken
819 firmware running.
821 isapnp= [ISAPNP]
822 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
824 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
825 Format:
826 <cpu number>,...,<cpu number>
827 or
828 <cpu number>-<cpu number> (must be a positive range in ascending order)
829 or a mixture
830 <cpu number>,...,<cpu number>-<cpu number>
831 This option can be used to specify one or more CPUs
832 to isolate from the general SMP balancing and scheduling
833 algorithms. The only way to move a process onto or off
834 an "isolated" CPU is via the CPU affinity syscalls.
835 <cpu number> begins at 0 and the maximum value is
836 "number of CPUs in system - 1".
838 This option is the preferred way to isolate CPUs. The
839 alternative -- manually setting the CPU mask of all
840 tasks in the system -- can cause problems and
841 suboptimal load balancer performance.
843 iucv= [HW,NET]
845 js= [HW,JOY] Analog joystick
846 See Documentation/input/joystick.txt.
848 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
849 specifies the amount of memory usable by the kernel
850 for non-movable allocations. The requested amount is
851 spread evenly throughout all nodes in the system. The
852 remaining memory in each node is used for Movable
853 pages. In the event, a node is too small to have both
854 kernelcore and Movable pages, kernelcore pages will
855 take priority and other nodes will have a larger number
856 of kernelcore pages. The Movable zone is used for the
857 allocation of pages that may be reclaimed or moved
858 by the page migration subsystem. This means that
859 HugeTLB pages may not be allocated from this zone.
860 Note that allocations like PTEs-from-HighMem still
861 use the HighMem zone if it exists, and the Normal
862 zone if it does not.
864 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
865 is similar to kernelcore except it specifies the
866 amount of memory used for migratable allocations.
867 If both kernelcore and movablecore is specified,
868 then kernelcore will be at *least* the specified
869 value but may be more. If movablecore on its own
870 is specified, the administrator must be careful
871 that the amount of memory usable for all allocations
872 is not too small.
874 keepinitrd [HW,ARM]
876 kstack=N [X86-32,X86-64] Print N words from the kernel stack
877 in oops dumps.
879 l2cr= [PPC]
881 lapic [X86-32,APIC] Enable the local APIC even if BIOS
882 disabled it.
884 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
885 C2 power state.
887 libata.dma= [LIBATA] DMA control
888 libata.dma=0 Disable all PATA and SATA DMA
889 libata.dma=1 PATA and SATA Disk DMA only
890 libata.dma=2 ATAPI (CDROM) DMA only
891 libata.dma=4 Compact Flash DMA only
892 Combinations also work, so libata.dma=3 enables DMA
893 for disks and CDROMs, but not CFs.
895 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
896 when set.
897 Format: <int>
899 load_ramdisk= [RAM] List of ramdisks to load from floppy
900 See Documentation/ramdisk.txt.
902 lockd.nlm_grace_period=P [NFS] Assign grace period.
903 Format: <integer>
905 lockd.nlm_tcpport=N [NFS] Assign TCP port.
906 Format: <integer>
908 lockd.nlm_timeout=T [NFS] Assign timeout value.
909 Format: <integer>
911 lockd.nlm_udpport=M [NFS] Assign UDP port.
912 Format: <integer>
914 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
915 Format: <irq>
917 loglevel= All Kernel Messages with a loglevel smaller than the
918 console loglevel will be printed to the console. It can
919 also be changed with klogd or other programs. The
920 loglevels are defined as follows:
922 0 (KERN_EMERG) system is unusable
923 1 (KERN_ALERT) action must be taken immediately
924 2 (KERN_CRIT) critical conditions
925 3 (KERN_ERR) error conditions
926 4 (KERN_WARNING) warning conditions
927 5 (KERN_NOTICE) normal but significant condition
928 6 (KERN_INFO) informational
929 7 (KERN_DEBUG) debug-level messages
931 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
932 Format: { n | nk | nM }
933 n must be a power of two. The default size
934 is set in the kernel config file.
936 logo.nologo [FB] Disables display of the built-in Linux logo.
937 This may be used to provide more screen space for
938 kernel log messages and is useful when debugging
939 kernel boot problems.
941 lp=0 [LP] Specify parallel ports to use, e.g,
942 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
943 lp=reset first parallel port). 'lp=0' disables the
944 lp=auto printer driver. 'lp=reset' (which can be
945 specified in addition to the ports) causes
946 attached printers to be reset. Using
947 lp=port1,port2,... specifies the parallel ports
948 to associate lp devices with, starting with
949 lp0. A port specification may be 'none' to skip
950 that lp device, or a parport name such as
951 'parport0'. Specifying 'lp=auto' instead of a
952 port specification list means that device IDs
953 from each port should be examined, to see if
954 an IEEE 1284-compliant printer is attached; if
955 so, the driver will manage that printer.
956 See also header of drivers/char/lp.c.
958 lpj=n [KNL]
959 Sets loops_per_jiffy to given constant, thus avoiding
960 time-consuming boot-time autodetection (up to 250 ms per
961 CPU). 0 enables autodetection (default). To determine
962 the correct value for your kernel, boot with normal
963 autodetection and see what value is printed. Note that
964 on SMP systems the preset will be applied to all CPUs,
965 which is likely to cause problems if your CPUs need
966 significantly divergent settings. An incorrect value
967 will cause delays in the kernel to be wrong, leading to
968 unpredictable I/O errors and other breakage. Although
969 unlikely, in the extreme case this might damage your
970 hardware.
972 ltpc= [NET]
973 Format: <io>,<irq>,<dma>
975 mac5380= [HW,SCSI] Format:
976 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
978 mac53c9x= [HW,SCSI] Format:
979 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
981 machvec= [IA64] Force the use of a particular machine-vector
982 (machvec) in a generic kernel.
983 Example: machvec=hpzx1_swiotlb
985 max_loop= [LOOP] Maximum number of loopback devices that can
986 be mounted
987 Format: <1-256>
989 maxcpus= [SMP] Maximum number of processors that an SMP kernel
990 should make use of. maxcpus=n : n >= 0 limits the
991 kernel to using 'n' processors. n=0 is a special case,
992 it is equivalent to "nosmp", which also disables
993 the IO APIC.
995 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
996 equal to this physical address is ignored.
998 max_luns= [SCSI] Maximum number of LUNs to probe.
999 Should be between 1 and 2^32-1.
1001 max_report_luns=
1002 [SCSI] Maximum number of LUNs received.
1003 Should be between 1 and 16384.
1005 mca-pentium [BUGS=X86-32]
1007 mcatest= [IA-64]
1009 mce [X86-32] Machine Check Exception
1011 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1013 md= [HW] RAID subsystems devices and level
1014 See Documentation/md.txt.
1016 mdacon= [MDA]
1017 Format: <first>,<last>
1018 Specifies range of consoles to be captured by the MDA.
1020 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1021 Amount of memory to be used when the kernel is not able
1022 to see the whole system memory or for test.
1023 [X86-32] Use together with memmap= to avoid physical
1024 address space collisions. Without memmap= PCI devices
1025 could be placed at addresses belonging to unused RAM.
1027 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1028 memory.
1030 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1031 E820 memory map, as specified by the user.
1032 Such memmap=exactmap lines can be constructed based on
1033 BIOS output or other requirements. See the memmap=nn@ss
1034 option description.
1036 memmap=nn[KMG]@ss[KMG]
1037 [KNL] Force usage of a specific region of memory
1038 Region of memory to be used, from ss to ss+nn.
1040 memmap=nn[KMG]#ss[KMG]
1041 [KNL,ACPI] Mark specific memory as ACPI data.
1042 Region of memory to be used, from ss to ss+nn.
1044 memmap=nn[KMG]$ss[KMG]
1045 [KNL,ACPI] Mark specific memory as reserved.
1046 Region of memory to be used, from ss to ss+nn.
1048 meye.*= [HW] Set MotionEye Camera parameters
1049 See Documentation/video4linux/meye.txt.
1051 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1052 Multi-Function General Purpose Timers on AMD Geode
1053 platforms.
1055 mga= [HW,DRM]
1057 mousedev.tap_time=
1058 [MOUSE] Maximum time between finger touching and
1059 leaving touchpad surface for touch to be considered
1060 a tap and be reported as a left button click (for
1061 touchpads working in absolute mode only).
1062 Format: <msecs>
1063 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1064 reporting absolute coordinates, such as tablets
1065 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1066 reporting absolute coordinates, such as tablets
1068 mpu401= [HW,OSS]
1069 Format: <io>,<irq>
1071 MTD_Partition= [MTD]
1072 Format: <name>,<region-number>,<size>,<offset>
1074 MTD_Region= [MTD] Format:
1075 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1077 mtdparts= [MTD]
1078 See drivers/mtd/cmdlinepart.c.
1080 mtouchusb.raw_coordinates=
1081 [HW] Make the MicroTouch USB driver use raw coordinates
1082 ('y', default) or cooked coordinates ('n')
1084 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1086 NCR_D700= [HW,SCSI]
1087 See header of drivers/scsi/NCR_D700.c.
1089 ncr5380= [HW,SCSI]
1091 ncr53c400= [HW,SCSI]
1093 ncr53c400a= [HW,SCSI]
1095 ncr53c406a= [HW,SCSI]
1097 ncr53c8xx= [HW,SCSI]
1099 netdev= [NET] Network devices parameters
1100 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1101 Note that mem_start is often overloaded to mean
1102 something different and driver-specific.
1103 This usage is only documented in each driver source
1104 file if at all.
1106 nfsaddrs= [NFS]
1107 See Documentation/nfsroot.txt.
1109 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1110 See Documentation/nfsroot.txt.
1112 nfs.callback_tcpport=
1113 [NFS] set the TCP port on which the NFSv4 callback
1114 channel should listen.
1116 nfs.idmap_cache_timeout=
1117 [NFS] set the maximum lifetime for idmapper cache
1118 entries.
1120 nfs.enable_ino64=
1121 [NFS] enable 64-bit inode numbers.
1122 If zero, the NFS client will fake up a 32-bit inode
1123 number for the readdir() and stat() syscalls instead
1124 of returning the full 64-bit number.
1125 The default is to return 64-bit inode numbers.
1127 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1128 when a NMI is triggered.
1129 Format: [state][,regs][,debounce][,die]
1131 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1133 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1134 emulation library even if a 387 maths coprocessor
1135 is present.
1137 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1138 caches in the slab allocator. Saves per-node memory,
1139 but will impact performance.
1141 noalign [KNL,ARM]
1143 noapic [SMP,APIC] Tells the kernel to not make use of any
1144 IOAPICs that may be present in the system.
1146 nobats [PPC] Do not use BATs for mapping kernel lowmem
1147 on "Classic" PPC cores.
1149 nocache [ARM]
1151 nodelayacct [KNL] Disable per-task delay accounting
1153 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1155 noexec [IA-64]
1157 noexec [X86-32,X86-64]
1158 noexec=on: enable non-executable mappings (default)
1159 noexec=off: disable nn-executable mappings
1161 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1162 register save and restore. The kernel will only save
1163 legacy floating-point registers on task switch.
1165 nohlt [BUGS=ARM]
1167 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1168 instruction doesn't work correctly and not to
1169 use it.
1171 nohalt [IA-64] Tells the kernel not to use the power saving
1172 function PAL_HALT_LIGHT when idle. This increases
1173 power-consumption. On the positive side, it reduces
1174 interrupt wake-up latency, which may improve performance
1175 in certain environments such as networked servers or
1176 real-time systems.
1178 nohz= [KNL] Boottime enable/disable dynamic ticks
1179 Valid arguments: on, off
1180 Default: on
1182 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1184 noirqdebug [X86-32] Disables the code which attempts to detect and
1185 disable unhandled interrupt sources.
1187 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1188 broken timer IRQ sources.
1190 noisapnp [ISAPNP] Disables ISA PnP code.
1192 noinitrd [RAM] Tells the kernel not to load any configured
1193 initial RAM disk.
1195 nointroute [IA-64]
1197 nojitter [IA64] Disables jitter checking for ITC timers.
1199 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1201 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1203 noltlbs [PPC] Do not use large page/tlb entries for kernel
1204 lowmem mapping on PPC40x.
1206 nomca [IA-64] Disable machine check abort handling
1208 nomce [X86-32] Machine Check Exception
1210 nomfgpt [X86-32] Disable Multi-Function General Purpose
1211 Timer usage (for AMD Geode machines).
1213 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1215 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1216 with UP alternatives
1218 noresidual [PPC] Don't use residual data on PReP machines.
1220 noresume [SWSUSP] Disables resume and restores original swap
1221 space.
1223 no-scroll [VGA] Disables scrollback.
1224 This is required for the Braillex ib80-piezo Braille
1225 reader made by F.H. Papenmeier (Germany).
1227 nosbagart [IA-64]
1229 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1231 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1232 and disable the IO APIC. legacy for "maxcpus=0".
1234 nosoftlockup [KNL] Disable the soft-lockup detector.
1236 nosync [HW,M68K] Disables sync negotiation for all devices.
1238 notsc [BUGS=X86-32] Disable Time Stamp Counter
1240 nousb [USB] Disable the USB subsystem
1242 nowb [ARM]
1244 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1245 one of ['zone', 'node', 'default'] can be specified
1246 This can be set from sysctl after boot.
1247 See Documentation/sysctl/vm.txt for details.
1249 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1251 opl3= [HW,OSS]
1252 Format: <io>
1254 oprofile.timer= [HW]
1255 Use timer interrupt instead of performance counters
1257 osst= [HW,SCSI] SCSI Tape Driver
1258 Format: <buffer_size>,<write_threshold>
1259 See also Documentation/scsi/st.txt.
1261 panic= [KNL] Kernel behaviour on panic
1262 Format: <timeout>
1264 parkbd.port= [HW] Parallel port number the keyboard adapter is
1265 connected to, default is 0.
1266 Format: <parport#>
1267 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1268 0 for XT, 1 for AT (default is AT).
1269 Format: <mode>
1271 parport= [HW,PPT] Specify parallel ports. 0 disables.
1272 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1273 Use 'auto' to force the driver to use any
1274 IRQ/DMA settings detected (the default is to
1275 ignore detected IRQ/DMA settings because of
1276 possible conflicts). You can specify the base
1277 address, IRQ, and DMA settings; IRQ and DMA
1278 should be numbers, or 'auto' (for using detected
1279 settings on that particular port), or 'nofifo'
1280 (to avoid using a FIFO even if it is detected).
1281 Parallel ports are assigned in the order they
1282 are specified on the command line, starting
1283 with parport0.
1285 parport_init_mode= [HW,PPT]
1286 Configure VIA parallel port to operate in
1287 a specific mode. This is necessary on Pegasos
1288 computer where firmware has no options for setting
1289 up parallel port mode and sets it to spp.
1290 Currently this function knows 686a and 8231 chips.
1291 Format: [spp|ps2|epp|ecp|ecpepp]
1293 pas2= [HW,OSS] Format:
1294 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1296 pas16= [HW,SCSI]
1297 See header of drivers/scsi/pas16.c.
1299 pause_on_oops=
1300 Halt all CPUs after the first oops has been printed for
1301 the specified number of seconds. This is to be used if
1302 your oopses keep scrolling off the screen.
1304 pcbit= [HW,ISDN]
1306 pcd. [PARIDE]
1307 See header of drivers/block/paride/pcd.c.
1308 See also Documentation/paride.txt.
1310 pci=option[,option...] [PCI] various PCI subsystem options:
1311 off [X86-32] don't probe for the PCI bus
1312 bios [X86-32] force use of PCI BIOS, don't access
1313 the hardware directly. Use this if your machine
1314 has a non-standard PCI host bridge.
1315 nobios [X86-32] disallow use of PCI BIOS, only direct
1316 hardware access methods are allowed. Use this
1317 if you experience crashes upon bootup and you
1318 suspect they are caused by the BIOS.
1319 conf1 [X86-32] Force use of PCI Configuration
1320 Mechanism 1.
1321 conf2 [X86-32] Force use of PCI Configuration
1322 Mechanism 2.
1323 noaer [PCIE] If the PCIEAER kernel config parameter is
1324 enabled, this kernel boot option can be used to
1325 disable the use of PCIE advanced error reporting.
1326 nodomains [PCI] Disable support for multiple PCI
1327 root domains (aka PCI segments, in ACPI-speak).
1328 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1329 Configuration
1330 nomsi [MSI] If the PCI_MSI kernel config parameter is
1331 enabled, this kernel boot option can be used to
1332 disable the use of MSI interrupts system-wide.
1333 nosort [X86-32] Don't sort PCI devices according to
1334 order given by the PCI BIOS. This sorting is
1335 done to get a device order compatible with
1336 older kernels.
1337 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1338 routing table. These calls are known to be buggy
1339 on several machines and they hang the machine
1340 when used, but on other computers it's the only
1341 way to get the interrupt routing table. Try
1342 this option if the kernel is unable to allocate
1343 IRQs or discover secondary PCI buses on your
1344 motherboard.
1345 rom [X86-32] Assign address space to expansion ROMs.
1346 Use with caution as certain devices share
1347 address decoders between ROMs and other
1348 resources.
1349 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1350 assigned automatically to PCI devices. You can
1351 make the kernel exclude IRQs of your ISA cards
1352 this way.
1353 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1354 of the PIRQ table (normally generated
1355 by the BIOS) if it is outside the
1356 F0000h-100000h range.
1357 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1358 useful if the kernel is unable to find your
1359 secondary buses and you want to tell it
1360 explicitly which ones they are.
1361 assign-busses [X86-32] Always assign all PCI bus
1362 numbers ourselves, overriding
1363 whatever the firmware may have done.
1364 usepirqmask [X86-32] Honor the possible IRQ mask stored
1365 in the BIOS $PIR table. This is needed on
1366 some systems with broken BIOSes, notably
1367 some HP Pavilion N5400 and Omnibook XE3
1368 notebooks. This will have no effect if ACPI
1369 IRQ routing is enabled.
1370 noacpi [X86-32] Do not use ACPI for IRQ routing
1371 or for PCI scanning.
1372 use_crs [X86-32] Use _CRS for PCI resource
1373 allocation.
1374 routeirq Do IRQ routing for all PCI devices.
1375 This is normally done in pci_enable_device(),
1376 so this option is a temporary workaround
1377 for broken drivers that don't call it.
1378 firmware [ARM] Do not re-enumerate the bus but instead
1379 just use the configuration from the
1380 bootloader. This is currently used on
1381 IXP2000 systems where the bus has to be
1382 configured a certain way for adjunct CPUs.
1383 noearly [X86] Don't do any early type 1 scanning.
1384 This might help on some broken boards which
1385 machine check when some devices' config space
1386 is read. But various workarounds are disabled
1387 and some IOMMU drivers will not work.
1388 bfsort Sort PCI devices into breadth-first order.
1389 This sorting is done to get a device
1390 order compatible with older (<= 2.4) kernels.
1391 nobfsort Don't sort PCI devices into breadth-first order.
1392 cbiosize=nn[KMG] The fixed amount of bus space which is
1393 reserved for the CardBus bridge's IO window.
1394 The default value is 256 bytes.
1395 cbmemsize=nn[KMG] The fixed amount of bus space which is
1396 reserved for the CardBus bridge's memory
1397 window. The default value is 64 megabytes.
1399 pcmv= [HW,PCMCIA] BadgePAD 4
1401 pd. [PARIDE]
1402 See Documentation/paride.txt.
1404 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1405 boot time.
1406 Format: { 0 | 1 }
1407 See arch/parisc/kernel/pdc_chassis.c
1409 pf. [PARIDE]
1410 See Documentation/paride.txt.
1412 pg. [PARIDE]
1413 See Documentation/paride.txt.
1415 pirq= [SMP,APIC] Manual mp-table setup
1416 See Documentation/i386/IO-APIC.txt.
1418 plip= [PPT,NET] Parallel port network link
1419 Format: { parport<nr> | timid | 0 }
1420 See also Documentation/parport.txt.
1422 pnpacpi= [ACPI]
1423 { off }
1425 pnpbios= [ISAPNP]
1426 { on | off | curr | res | no-curr | no-res }
1428 pnp_reserve_irq=
1429 [ISAPNP] Exclude IRQs for the autoconfiguration
1431 pnp_reserve_dma=
1432 [ISAPNP] Exclude DMAs for the autoconfiguration
1434 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1435 Ranges are in pairs (I/O port base and size).
1437 pnp_reserve_mem=
1438 [ISAPNP] Exclude memory regions for the
1439 autoconfiguration.
1440 Ranges are in pairs (memory base and size).
1442 print-fatal-signals=
1443 [KNL] debug: print fatal signals
1444 print-fatal-signals=1: print segfault info to
1445 the kernel console.
1446 default: off.
1448 printk.time= Show timing data prefixed to each printk message line
1449 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1451 profile= [KNL] Enable kernel profiling via /proc/profile
1452 Format: [schedule,]<number>
1453 Param: "schedule" - profile schedule points.
1454 Param: <number> - step/bucket size as a power of 2 for
1455 statistical time based profiling.
1456 Param: "sleep" - profile D-state sleeping (millisecs).
1457 Requires CONFIG_SCHEDSTATS
1458 Param: "kvm" - profile VM exits.
1460 processor.max_cstate= [HW,ACPI]
1461 Limit processor to maximum C-state
1462 max_cstate=9 overrides any DMI blacklist limit.
1464 processor.nocst [HW,ACPI]
1465 Ignore the _CST method to determine C-states,
1466 instead using the legacy FADT method
1468 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1469 before loading.
1470 See Documentation/ramdisk.txt.
1472 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1473 probe for; one of (bare|imps|exps|lifebook|any).
1474 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1475 per second.
1476 psmouse.resetafter= [HW,MOUSE]
1477 Try to reset the device after so many bad packets
1478 (0 = never).
1479 psmouse.resolution=
1480 [HW,MOUSE] Set desired mouse resolution, in dpi.
1481 psmouse.smartscroll=
1482 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1483 0 = disabled, 1 = enabled (default).
1485 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1486 Format:
1487 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1489 pt. [PARIDE]
1490 See Documentation/paride.txt.
1492 pty.legacy_count=
1493 [KNL] Number of legacy pty's. Overwrites compiled-in
1494 default number.
1496 quiet [KNL] Disable most log messages
1498 r128= [HW,DRM]
1500 raid= [HW,RAID]
1501 See Documentation/md.txt.
1503 ramdisk_blocksize= [RAM]
1504 See Documentation/ramdisk.txt.
1506 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1507 See Documentation/ramdisk.txt.
1509 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1510 RCU callbacks to process in one batch.
1512 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1513 RCU callbacks over which batch limiting is disabled.
1515 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1516 RCU callbacks below which batch limiting is re-enabled.
1518 rdinit= [KNL]
1519 Format: <full_path>
1520 Run specified binary instead of /init from the ramdisk,
1521 used for early userspace startup. See initrd.
1523 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1524 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1525 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1527 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1529 reservetop= [X86-32]
1530 Format: nn[KMG]
1531 Reserves a hole at the top of the kernel virtual
1532 address space.
1534 reset_devices [KNL] Force drivers to reset the underlying device
1535 during initialization.
1537 resume= [SWSUSP]
1538 Specify the partition device for software suspend
1540 resume_offset= [SWSUSP]
1541 Specify the offset from the beginning of the partition
1542 given by "resume=" at which the swap header is located,
1543 in <PAGE_SIZE> units (needed only for swap files).
1544 See Documentation/power/swsusp-and-swap-files.txt
1546 retain_initrd [RAM] Keep initrd memory after extraction
1548 rhash_entries= [KNL,NET]
1549 Set number of hash buckets for route cache
1551 riscom8= [HW,SERIAL]
1552 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1554 ro [KNL] Mount root device read-only on boot
1556 root= [KNL] Root filesystem
1558 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1559 mount the root filesystem
1561 rootflags= [KNL] Set root filesystem mount option string
1563 rootfstype= [KNL] Set root filesystem type
1565 rootwait [KNL] Wait (indefinitely) for root device to show up.
1566 Useful for devices that are detected asynchronously
1567 (e.g. USB and MMC devices).
1569 root_plug.vendor_id=
1570 [ROOTPLUG] Override the default vendor ID
1572 root_plug.product_id=
1573 [ROOTPLUG] Override the default product ID
1575 root_plug.debug=
1576 [ROOTPLUG] Enable debugging output
1578 rw [KNL] Mount root device read-write on boot
1580 S [KNL] Run init in single mode
1582 sa1100ir [NET]
1583 See drivers/net/irda/sa1100_ir.c.
1585 sbni= [NET] Granch SBNI12 leased line adapter
1587 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1588 Format: <io>[,<timeout>[,<isapnp>]]
1590 scsi_debug_*= [SCSI]
1591 See drivers/scsi/scsi_debug.c.
1593 scsi_default_dev_flags=
1594 [SCSI] SCSI default device flags
1595 Format: <integer>
1597 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1598 Format: <vendor>:<model>:<flags>
1599 (flags are integer value)
1601 scsi_logging_level= [SCSI] a bit mask of logging levels
1602 See drivers/scsi/scsi_logging.h for bits. Also
1603 settable via sysctl at dev.scsi.logging_level
1604 (/proc/sys/dev/scsi/logging_level).
1605 There is also a nice 'scsi_logging_level' script in the
1606 S390-tools package, available for download at
1607 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1609 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1610 discovered. async scans them in kernel threads,
1611 allowing boot to proceed. none ignores them, expecting
1612 user space to do the scan.
1614 selinux [SELINUX] Disable or enable SELinux at boot time.
1615 Format: { "0" | "1" }
1616 See security/selinux/Kconfig help text.
1617 0 -- disable.
1618 1 -- enable.
1619 Default value is set via kernel config option.
1620 If enabled at boot time, /selinux/disable can be used
1621 later to disable prior to initial policy load.
1623 selinux_compat_net =
1624 [SELINUX] Set initial selinux_compat_net flag value.
1625 Format: { "0" | "1" }
1626 0 -- use new secmark-based packet controls
1627 1 -- use legacy packet controls
1628 Default value is 0 (preferred).
1629 Value can be changed at runtime via
1630 /selinux/compat_net.
1632 serialnumber [BUGS=X86-32]
1634 shapers= [NET]
1635 Maximal number of shapers.
1637 sim710= [SCSI,HW]
1638 See header of drivers/scsi/sim710.c.
1640 simeth= [IA-64]
1641 simscsi=
1643 slram= [HW,MTD]
1645 slub_debug[=options[,slabs]] [MM, SLUB]
1646 Enabling slub_debug allows one to determine the
1647 culprit if slab objects become corrupted. Enabling
1648 slub_debug can create guard zones around objects and
1649 may poison objects when not in use. Also tracks the
1650 last alloc / free. For more information see
1651 Documentation/vm/slub.txt.
1653 slub_max_order= [MM, SLUB]
1654 Determines the maximum allowed order for slabs.
1655 A high setting may cause OOMs due to memory
1656 fragmentation. For more information see
1657 Documentation/vm/slub.txt.
1659 slub_min_objects= [MM, SLUB]
1660 The minimum number of objects per slab. SLUB will
1661 increase the slab order up to slub_max_order to
1662 generate a sufficiently large slab able to contain
1663 the number of objects indicated. The higher the number
1664 of objects the smaller the overhead of tracking slabs
1665 and the less frequently locks need to be acquired.
1666 For more information see Documentation/vm/slub.txt.
1668 slub_min_order= [MM, SLUB]
1669 Determines the mininum page order for slabs. Must be
1670 lower than slub_max_order.
1671 For more information see Documentation/vm/slub.txt.
1673 slub_nomerge [MM, SLUB]
1674 Disable merging of slabs with similar size. May be
1675 necessary if there is some reason to distinguish
1676 allocs to different slabs. Debug options disable
1677 merging on their own.
1678 For more information see Documentation/vm/slub.txt.
1680 smart2= [HW]
1681 Format: <io1>[,<io2>[,...,<io8>]]
1683 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1684 attempt to substitute SMP alternatives once at boot.
1686 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1687 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1688 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1689 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1690 smsc-ircc2.ircc_irq= [HW] IRQ line
1691 smsc-ircc2.ircc_dma= [HW] DMA channel
1692 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1693 0: Toshiba Satellite 1800 (GP data pin select)
1694 1: Fast pin select (default)
1695 2: ATC IRMode
1697 snd-ad1816a= [HW,ALSA]
1699 snd-ad1848= [HW,ALSA]
1701 snd-ali5451= [HW,ALSA]
1703 snd-als100= [HW,ALSA]
1705 snd-als4000= [HW,ALSA]
1707 snd-azt2320= [HW,ALSA]
1709 snd-cmi8330= [HW,ALSA]
1711 snd-cmipci= [HW,ALSA]
1713 snd-cs4231= [HW,ALSA]
1715 snd-cs4232= [HW,ALSA]
1717 snd-cs4236= [HW,ALSA]
1719 snd-cs4281= [HW,ALSA]
1721 snd-cs46xx= [HW,ALSA]
1723 snd-dt019x= [HW,ALSA]
1725 snd-dummy= [HW,ALSA]
1727 snd-emu10k1= [HW,ALSA]
1729 snd-ens1370= [HW,ALSA]
1731 snd-ens1371= [HW,ALSA]
1733 snd-es968= [HW,ALSA]
1735 snd-es1688= [HW,ALSA]
1737 snd-es18xx= [HW,ALSA]
1739 snd-es1938= [HW,ALSA]
1741 snd-es1968= [HW,ALSA]
1743 snd-fm801= [HW,ALSA]
1745 snd-gusclassic= [HW,ALSA]
1747 snd-gusextreme= [HW,ALSA]
1749 snd-gusmax= [HW,ALSA]
1751 snd-hdsp= [HW,ALSA]
1753 snd-ice1712= [HW,ALSA]
1755 snd-intel8x0= [HW,ALSA]
1757 snd-interwave= [HW,ALSA]
1759 snd-interwave-stb=
1760 [HW,ALSA]
1762 snd-korg1212= [HW,ALSA]
1764 snd-maestro3= [HW,ALSA]
1766 snd-mpu401= [HW,ALSA]
1768 snd-mtpav= [HW,ALSA]
1770 snd-nm256= [HW,ALSA]
1772 snd-opl3sa2= [HW,ALSA]
1774 snd-opti92x-ad1848=
1775 [HW,ALSA]
1777 snd-opti92x-cs4231=
1778 [HW,ALSA]
1780 snd-opti93x= [HW,ALSA]
1782 snd-pmac= [HW,ALSA]
1784 snd-rme32= [HW,ALSA]
1786 snd-rme96= [HW,ALSA]
1788 snd-rme9652= [HW,ALSA]
1790 snd-sb8= [HW,ALSA]
1792 snd-sb16= [HW,ALSA]
1794 snd-sbawe= [HW,ALSA]
1796 snd-serial= [HW,ALSA]
1798 snd-sgalaxy= [HW,ALSA]
1800 snd-sonicvibes= [HW,ALSA]
1802 snd-sun-amd7930=
1803 [HW,ALSA]
1805 snd-sun-cs4231= [HW,ALSA]
1807 snd-trident= [HW,ALSA]
1809 snd-usb-audio= [HW,ALSA,USB]
1811 snd-via82xx= [HW,ALSA]
1813 snd-virmidi= [HW,ALSA]
1815 snd-wavefront= [HW,ALSA]
1817 snd-ymfpci= [HW,ALSA]
1819 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1820 See Documentation/sonypi.txt
1822 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1823 See Documentation/specialix.txt.
1825 spia_io_base= [HW,MTD]
1826 spia_fio_base=
1827 spia_pedr=
1828 spia_peddr=
1830 sscape= [HW,OSS]
1831 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1833 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1834 See Documentation/scsi/st.txt.
1836 st0x= [HW,SCSI]
1837 See header of drivers/scsi/seagate.c.
1839 sti= [PARISC,HW]
1840 Format: <num>
1841 Set the STI (builtin display/keyboard on the HP-PARISC
1842 machines) console (graphic card) which should be used
1843 as the initial boot-console.
1844 See also comment in drivers/video/console/sticore.c.
1846 sti_font= [HW]
1847 See comment in drivers/video/console/sticore.c.
1849 stifb= [HW]
1850 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1852 sunrpc.pool_mode=
1853 [NFS]
1854 Control how the NFS server code allocates CPUs to
1855 service thread pools. Depending on how many NICs
1856 you have and where their interrupts are bound, this
1857 option will affect which CPUs will do NFS serving.
1858 Note: this parameter cannot be changed while the
1859 NFS server is running.
1861 auto the server chooses an appropriate mode
1862 automatically using heuristics
1863 global a single global pool contains all CPUs
1864 percpu one pool for each CPU
1865 pernode one pool for each NUMA node (equivalent
1866 to global on non-NUMA machines)
1868 swiotlb= [IA-64] Number of I/O TLB slabs
1870 switches= [HW,M68k]
1872 sym53c416= [HW,SCSI]
1873 See header of drivers/scsi/sym53c416.c.
1875 sysrq_always_enabled
1876 [KNL]
1877 Ignore sysrq setting - this boot parameter will
1878 neutralize any effect of /proc/sys/kernel/sysrq.
1879 Useful for debugging.
1881 t128= [HW,SCSI]
1882 See header of drivers/scsi/t128.c.
1884 tdfx= [HW,DRM]
1886 thash_entries= [KNL,NET]
1887 Set number of hash buckets for TCP connection
1889 thermal.act= [HW,ACPI]
1890 -1: disable all active trip points in all thermal zones
1891 <degrees C>: override all lowest active trip points
1893 thermal.crt= [HW,ACPI]
1894 -1: disable all critical trip points in all thermal zones
1895 <degrees C>: lower all critical trip points
1897 thermal.nocrt= [HW,ACPI]
1898 Set to disable actions on ACPI thermal zone
1899 critical and hot trip points.
1901 thermal.off= [HW,ACPI]
1902 1: disable ACPI thermal control
1904 thermal.psv= [HW,ACPI]
1905 -1: disable all passive trip points
1906 <degrees C>: override all passive trip points to this value
1908 thermal.tzp= [HW,ACPI]
1909 Specify global default ACPI thermal zone polling rate
1910 <deci-seconds>: poll all this frequency
1911 0: no polling (default)
1913 time Show timing data prefixed to each printk message line
1914 [deprecated, see 'printk.time']
1916 tipar.timeout= [HW,PPT]
1917 Set communications timeout in tenths of a second
1918 (default 15).
1920 tipar.delay= [HW,PPT]
1921 Set inter-bit delay in microseconds (default 10).
1923 tmc8xx= [HW,SCSI]
1924 See header of drivers/scsi/seagate.c.
1926 tmscsim= [HW,SCSI]
1927 See comment before function dc390_setup() in
1928 drivers/scsi/tmscsim.c.
1930 tp720= [HW,PS2]
1932 trix= [HW,OSS] MediaTrix AudioTrix Pro
1933 Format:
1934 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1936 turbografx.map[2|3]= [HW,JOY]
1937 TurboGraFX parallel port interface
1938 Format:
1939 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1940 See also Documentation/input/joystick-parport.txt
1942 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1943 See header of drivers/scsi/u14-34f.c.
1945 uart401= [HW,OSS]
1946 Format: <io>,<irq>
1948 uart6850= [HW,OSS]
1949 Format: <io>,<irq>
1951 uhci-hcd.ignore_oc=
1952 [USB] Ignore overcurrent events (default N).
1953 Some badly-designed motherboards generate lots of
1954 bogus events, for ports that aren't wired to
1955 anything. Set this parameter to avoid log spamming.
1956 Note that genuine overcurrent events won't be
1957 reported either.
1959 usbcore.autosuspend=
1960 [USB] The autosuspend time delay (in seconds) used
1961 for newly-detected USB devices (default 2). This
1962 is the time required before an idle device will be
1963 autosuspended. Devices for which the delay is set
1964 to a negative value won't be autosuspended at all.
1966 usbhid.mousepoll=
1967 [USBHID] The interval which mice are to be polled at.
1969 vdso= [X86-32,SH,x86-64]
1970 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1971 vdso=1: enable VDSO (default)
1972 vdso=0: disable VDSO mapping
1974 vector= [IA-64,SMP]
1975 vector=percpu: enable percpu vector domain
1977 video= [FB] Frame buffer configuration
1978 See Documentation/fb/modedb.txt.
1980 vga= [BOOT,X86-32] Select a particular video mode
1981 See Documentation/i386/boot.txt and
1982 Documentation/svga.txt.
1983 Use vga=ask for menu.
1984 This is actually a boot loader parameter; the value is
1985 passed to the kernel using a special protocol.
1987 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1988 size of <nn>. This can be used to increase the
1989 minimum size (128MB on x86). It can also be used to
1990 decrease the size and leave more room for directly
1991 mapped kernel RAM.
1993 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1994 Format: <command>
1996 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1997 Format: <command>
1999 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2000 Format: <command>
2002 waveartist= [HW,OSS]
2003 Format: <io>,<irq>,<dma>,<dma2>
2005 wd33c93= [HW,SCSI]
2006 See header of drivers/scsi/wd33c93.c.
2008 wd7000= [HW,SCSI]
2009 See header of drivers/scsi/wd7000.c.
2011 wdt= [WDT] Watchdog
2012 See Documentation/watchdog/wdt.txt.
2014 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2015 xd_geo= See header of drivers/block/xd.c.
2017 xirc2ps_cs= [NET,PCMCIA]
2018 Format:
2019 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2021 norandmaps Don't use address space randomization
2022 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2024 ______________________________________________________________________
2026 TODO:
2028 Add documentation for ALSA options.
2029 Add more DRM drivers.