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
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 (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
92 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
100 X86-32 X86-32, aka i386 architecture is enabled.
101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
105 In addition, the following text indicates that the option:
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
111 Parameters denoted with BOOT are actually interpreted by the boot
112 loader, and have no meaning to the kernel directly.
113 Do not modify the syntax of boot loader parameters without extreme
114 need or coordination with <Documentation/i386/boot.txt>.
116 There are also arch-specific kernel-parameters not documented here.
117 See for example <Documentation/x86_64/boot-options.txt>.
119 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120 a trailing = on the name of any parameter states that that parameter will
121 be entered as an environment variable, whereas its absence indicates that
122 it will appear as a kernel argument readable via /proc/cmdline by programs
123 running once the system is up.
125 The number of kernel parameters is not limited, but the length of the
126 complete command line (parameters including spaces etc.) is limited to
127 a fixed number of characters. This limit depends on the architecture
128 and is between 256 and 4096 characters. It is defined in the file
129 ./include/asm/setup.h as COMMAND_LINE_SIZE.
132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
134 Format: { force | off | ht | strict | noirq }
135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
139 strict -- Be less tolerant of platforms that are not
140 strictly ACPI specification compliant.
142 See also Documentation/power/pm.txt, pci=noacpi
144 acpi_apic_instance= [ACPI, IOAPIC]
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
150 acpi_sleep= [HW,ACPI] Sleep options
151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
163 Format: { level | edge | high | low }
165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 Format: <irq>,<irq>...
177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
178 Format: <irq>,<irq>...
180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
190 acpi_serialize [HW,ACPI] force serialization of AML methods
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
200 acpi.debug_layer= [HW,ACPI]
202 Each bit of the <int> indicates an ACPI debug layer,
203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
217 acpi.debug_level= [HW,ACPI]
219 Each bit of the <int> indicates an ACPI debug level,
220 which corresponds to the level in an ACPI_DEBUG_PRINT
221 statement. After system has booted up, this mask
222 can be set via /sys/module/acpi/parameters/debug_level.
224 CONFIG_ACPI_DEBUG must be enabled for this to produce
225 any output. The number can be in decimal or prefixed
226 with 0x in hex. Some of these options produce so much
227 output that the system is unusable.
229 The following global components are defined by the
242 0x800 operation region
248 0x20000 user requests
250 The number can be in decimal or prefixed with 0x in hex.
251 Warning: Many of these options can produce a lot of
252 output and make your system unusable. Be very careful.
254 acpi.power_nocheck= [HW,ACPI]
255 Format: 1/0 enable/disable the check of power state.
256 On some bogus BIOS the _PSC object/_STA object of
257 power resource can't return the correct device power
258 state. In such case it is unneccessary to check its
259 power state again in power transition.
260 1 : disable the power state check
262 acpi_pm_good [X86-32,X86-64]
263 Override the pmtimer bug detection: force the kernel
264 to assume that this machine's pmtimer latches its value
265 and always returns good values.
268 { off | try_unsupported }
269 off: disable AGP support
270 try_unsupported: try to drive unsupported chipsets
271 (may crash computer or cause data corruption)
273 enable_timer_pin_1 [i386,x86-64]
274 Enable PIN 1 of APIC timer
275 Can be useful to work around chipset bugs
276 (in particular on some ATI chipsets).
277 The kernel tries to set a reasonable default.
279 disable_timer_pin_1 [i386,x86-64]
280 Disable PIN 1 of APIC timer
281 Can be useful to work around chipset bugs.
284 Format: <io>,<irq>,<dma>,<dma2>,<type>
287 See header of drivers/scsi/advansys.c.
289 advwdt= [HW,WDT] Advantech WDT
290 Format: <iostart>,<iostop>
292 aedsp16= [HW,OSS] Audio Excel DSP 16
293 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
294 See also header of sound/oss/aedsp16.c.
297 See Documentation/scsi/aha152x.txt.
300 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
303 See Documentation/scsi/aic7xxx.txt.
306 See Documentation/scsi/aic79xx.txt.
308 amd_iommu= [HW,X86-84]
309 Pass parameters to the AMD IOMMU driver in the system.
311 isolate - enable device isolation (each device, as far
312 as possible, will get its own protection
314 amd_iommu_size= [HW,X86-64]
315 Define the size of the aperture for the AMD IOMMU
316 driver. Possible values are:
317 '32M', '64M' (default), '128M', '256M', '512M', '1G'
319 amijoy.map= [HW,JOY] Amiga joystick support
320 Map of devices attached to JOY0DAT and JOY1DAT
322 See also Documentation/kernel/input/joystick.txt
324 analog.map= [HW,JOY] Analog joystick and gamepad support
325 Specifies type or capabilities of an analog joystick
326 connected to one of 16 gameports
327 Format: <type1>,<type2>,..<type16>
330 Power management functions (SPARCstation-4/5 + deriv.)
332 Disable APC CPU standby support. SPARCstation-Fox does
333 not play well with APC CPU idle - disable it if you have
334 APC and your system crashes randomly.
336 apic= [APIC,i386] Advanced Programmable Interrupt Controller
337 Change the output verbosity whilst booting
338 Format: { quiet (default) | verbose | debug }
339 Change the amount of debugging information output
340 when initialising the APIC and IO-APIC components.
342 apm= [APM] Advanced Power Management
343 See header of arch/x86/kernel/apm_32.c.
345 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
346 Format: <io>,<irq>,<nodeID>
350 atarimouse= [HW,MOUSE] Atari Mouse
352 atascsi= [HW,SCSI] Atari SCSI
354 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
355 EzKey and similar keyboards
357 atkbd.reset= [HW] Reset keyboard during initialization
359 atkbd.set= [HW] Select keyboard code set
360 Format: <int> (2 = AT (default), 3 = PS/2)
362 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
365 atkbd.softraw= [HW] Choose between synthetic and real raw mode
366 Format: <bool> (0 = real, 1 = synthetic (default))
368 atkbd.softrepeat= [HW]
369 Use software keyboard repeat
373 baycom_epp= [HW,AX25]
376 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
378 See header of drivers/net/hamradio/baycom_par.c.
380 baycom_ser_fdx= [HW,AX25]
381 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
382 Format: <io>,<irq>,<mode>[,<baud>]
383 See header of drivers/net/hamradio/baycom_ser_fdx.c.
385 baycom_ser_hdx= [HW,AX25]
386 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
387 Format: <io>,<irq>,<mode>
388 See header of drivers/net/hamradio/baycom_ser_hdx.c.
390 boot_delay= Milliseconds to delay each printk during boot.
391 Values larger than 10 seconds (10000) are changed to
395 bootmem_debug [KNL] Enable bootmem allocator debug messages.
397 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
398 bttv.radio= Most important insmod options are available as
400 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
401 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
404 See drivers/scsi/BusLogic.c, comment before function
405 BusLogic_ParseDriverOptions().
407 c101= [NET] Moxa C101 synchronous serial card
409 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
410 Sometimes CPU hardware bugs make them report the cache
411 size incorrectly. The kernel will attempt work arounds
412 to fix known problems, but for some CPUs it is not
413 possible to determine what the correct size should be.
414 This option provides an override for these situations.
416 security= [SECURITY] Choose a security module to enable at boot.
417 If this boot parameter is not specified, only the first
418 security module asking for security registration will be
419 loaded. An invalid security module name will be treated
420 as if no module has been chosen.
423 [SECURITY] Disable capabilities. This would normally
424 be used only if an alternative security model is to be
425 configured. Potentially dangerous and should only be
426 used if you are entirely sure of the consequences.
428 ccw_timeout_log [S390]
429 See Documentation/s390/CommonIO for details.
431 cgroup_disable= [KNL] Disable a particular controller
432 Format: {name of the controller(s) to disable}
433 {Currently supported controllers - "memory"}
435 checkreqprot [SELINUX] Set initial checkreqprot flag value.
436 Format: { "0" | "1" }
437 See security/selinux/Kconfig help text.
438 0 -- check protection applied by kernel (includes
439 any implied execute protection).
440 1 -- check protection requested by application.
441 Default value is set via a kernel config option.
442 Value can be changed at runtime via
443 /selinux/checkreqprot.
446 See Documentation/s390/CommonIO for details.
448 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
450 Forces specified clocksource (if available) to be used
451 when calculating gettimeofday(). If specified
452 clocksource is not available, it defaults to PIT.
453 Format: { pit | tsc | cyclone | pmtmr }
455 clocksource= [GENERIC_TIME] Override the default clocksource
457 Override the default clocksource and use the clocksource
458 with the name specified.
459 Some clocksource names to choose from, depending on
461 [all] jiffies (this is the base, fallback clocksource)
463 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
464 pxa_timer,timer3,32k_counter,timer0_1
466 [X86-32] pit,hpet,tsc,vmi-timer;
467 scx200_hrt on Geode; cyclone on IBM x440
475 clearcpuid=BITNUM [X86]
476 Disable CPUID feature X for the kernel. See
477 include/asm-x86/cpufeature.h for the valid bit numbers.
478 Note the Linux specific bits are not necessarily
479 stable over kernel options, but the vendor specific
481 Also note that user programs calling CPUID directly
482 or using the feature without checking anything
483 will still see it. This just prevents it from
484 being used by the kernel or shown in /proc/cpuinfo.
485 Also note the kernel might malfunction if you disable
488 code_bytes [IA32/X86_64] How many bytes of object code to print
495 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
496 over the 8254 in addition to over the IO-APIC. The
497 kernel tries to set a sensible default.
499 hpet= [X86-32,HPET] option to control HPET usage
500 Format: { enable (default) | disable | force }
501 disable: disable HPET and use PIT instead
502 force: allow force enabled of undocumented chips (ICH4,
505 com20020= [HW,NET] ARCnet - COM20020 chipset
507 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
509 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
513 ARCnet - COM90xx chipset (memory-mapped buffers)
514 Format: <io>[,<irq>[,<memstart>]]
516 condev= [HW,S390] console device
519 console= [KNL] Output console device and options.
521 tty<n> Use the virtual console device <n>.
525 Use the specified serial port. The options are of
526 the form "bbbbpnf", where "bbbb" is the baud rate,
527 "p" is parity ("n", "o", or "e"), "n" is number of
528 bits, and "f" is flow control ("r" for RTS or
529 omit it). Default is "9600n8".
531 See Documentation/serial-console.txt for more
533 Documentation/networking/netconsole.txt for an
536 uart[8250],io,<addr>[,options]
537 uart[8250],mmio,<addr>[,options]
538 Start an early, polled-mode console on the 8250/16550
539 UART at the specified I/O port or MMIO address,
540 switching to the matching ttyS device later. The
541 options are the same as for ttyS, above.
543 If the device connected to the port is not a TTY but a braille
544 device, prepend "brl," before the device type, for instance
546 For now, only VisioBraille is supported.
548 earlycon= [KNL] Output early console device and options.
549 uart[8250],io,<addr>[,options]
550 uart[8250],mmio,<addr>[,options]
551 Start an early, polled-mode console on the 8250/16550
552 UART at the specified I/O port or MMIO address.
553 The options are the same as for ttyS, above.
556 [HW] Never suspend the console
557 Disable suspending of consoles during suspend and
558 hibernate operations. Once disabled, debugging
559 messages can reach various consoles while the rest
560 of the system is being put to sleep (ie, while
561 debugging driver suspend/resume hooks). This may
562 not work reliably with all consoles, but is known
563 to work with serial and VGA consoles.
565 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
567 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
569 crashkernel=nn[KMG]@ss[KMG]
570 [KNL] Reserve a chunk of physical memory to
571 hold a kernel to switch to with kexec on panic.
573 crashkernel=range1:size1[,range2:size2,...][@offset]
574 [KNL] Same as above, but depends on the memory
575 in the running system. The syntax of range is
576 start-[end] where start and end are both
577 a memory unit (amount[KMG]). See also
578 Documentation/kdump/kdump.txt for a example.
581 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
586 cs89x0_media= [HW,NET]
587 Format: { rj45 | aui | bnc }
590 See header of drivers/s390/block/dasd_devmap.c.
592 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
593 (one device per port)
594 Format: <port#>,<type>
595 See also Documentation/input/joystick-parport.txt
597 debug [KNL] Enable kernel debugging (events log level).
600 [KNL] verbose self-tests
602 Print debugging info while doing the locking API
604 We default to 0 (no extra messages), setting it to
605 1 will print _a lot_ more information - normally
606 only useful to kernel developers.
608 debug_objects [KNL] Enable object debugging
610 debugpat [X86] Enable PAT debugging
612 decnet.addr= [HW,NET]
613 Format: <area>[,<node>]
614 See also Documentation/networking/decnet.txt.
617 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
618 Change the default blue palette of the console.
619 This is a 16-member array composed of values
623 Format: <green0>,<green1>,<green2>,...,<green15>
624 Change the default green palette of the console.
625 This is a 16-member array composed of values
629 Format: <red0>,<red1>,<red2>,...,<red15>
630 Change the default red palette of the console.
631 This is a 16-member array composed of values
637 Set system-wide default UTF-8 mode for all tty's.
638 Default is 1, i.e. UTF-8 mode is enabled for all
639 newly opened terminals.
642 Set number of hash buckets for dentry cache.
645 IO parameters + enable/disable command.
647 digiepca= [HW,SERIAL]
648 See drivers/char/README.epca and
649 Documentation/digiepca.txt.
651 disable_mtrr_cleanup [X86]
652 enable_mtrr_cleanup [X86]
653 The kernel tries to adjust MTRR layout from continuous
654 to discrete, to make X server driver able to add WB
655 entry later. This parameter enables/disables that.
657 mtrr_chunk_size=nn[KMG] [X86]
658 used for mtrr cleanup. It is largest continous chunk
659 that could hold holes aka. UC entries.
661 mtrr_gran_size=nn[KMG] [X86]
662 Used for mtrr cleanup. It is granularity of mtrr block.
664 Large value could prevent small alignment from
667 mtrr_spare_reg_nr=n [X86]
669 Range: 0,7 : spare reg number
671 Used for mtrr cleanup. It is spare mtrr entries number.
672 Set to 2 or more if your graphical card needs more.
674 disable_mtrr_trim [X86, Intel and AMD only]
675 By default the kernel will trim any uncacheable
676 memory out of your available memory pool based on
677 MTRR settings. This parameter disables that behavior,
678 possibly causing your machine to run very slowly.
680 dmasound= [HW,OSS] Sound subsystem buffers
686 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
688 earlyprintk=serial[,ttySn[,baudrate]]
690 Append ",keep" to not disable it when the real console
693 Only vga or serial at a time, not both.
695 Currently only ttyS0 and ttyS1 are supported.
697 Interaction with the standard serial driver is not
700 The VGA output is eventually overwritten by the real
706 Format: {"off" | "on" | "skip[mbr]"}
708 eisa_irq_edge= [PARISC,HW]
709 See header of drivers/parisc/eisa.c.
712 See comment before function elanfreq_setup() in
713 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
716 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
717 See Documentation/block/as-iosched.txt and
718 Documentation/block/deadline-iosched.txt for details.
720 elfcorehdr= [X86-32, X86_64]
721 Specifies physical address of start of kernel core
722 image elf header. Generally kexec loader will
723 pass this option to capture kernel.
724 See Documentation/kdump/kdump.txt for details.
726 enforcing [SELINUX] Set initial enforcing status.
728 See security/selinux/Kconfig help text.
729 0 -- permissive (log only, no denials).
730 1 -- enforcing (deny and log).
732 Value can be changed at runtime via /selinux/enforce.
735 Format: <spdif>,[<nomix>,[<amplifier>]]
736 See also header of sound/oss/es1371.c.
738 ether= [HW,NET] Ethernet cards parameters
739 This option is obsoleted by the "netdev=" option, which
740 has equivalent usage. See its documentation for details.
742 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
747 fail_make_request=[KNL]
748 General fault injection mechanism.
749 Format: <interval>,<probability>,<space>,<times>
750 See also /Documentation/fault-injection/.
753 See header of drivers/scsi/fd_mcs.c.
756 See header of drivers/scsi/fdomain.c.
759 See Documentation/floppy.txt.
761 force_pal_cache_flush
762 [IA-64] Avoid check_sal_cache_flush which may hang on
763 buggy SAL_CACHE_FLUSH implementations. Using this
764 parameter will force ia64_sal_cache_flush to call
765 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
768 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
769 support via parallel port (up to 5 devices per port)
770 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
771 See also Documentation/input/joystick-parport.txt
775 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
780 See header of drivers/scsi/gdth.c.
782 gpt [EFI] Forces disk with valid GPT signature but
783 invalid Protective MBR to be treated as GPT.
787 hashdist= [KNL,NUMA] Large hashes allocated during boot
788 are distributed across NUMA nodes. Defaults on
789 for IA-64, off otherwise.
790 Format: 0 | 1 (for off | on)
792 hcl= [IA-64] SGI's Hardware Graph compatibility layer
794 hd= [EIDE] (E)IDE hard drive subsystem geometry
795 Format: <cyl>,<head>,<sect>
797 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
798 size of <nn>. This works even on boxes that have no
799 highmem otherwise. This also works to reduce highmem
800 size on bigger boxes.
802 highres= [KNL] Enable/disable high resolution timer mode.
803 Valid parameters: "on", "off"
807 See Documentation/isdn/README.HiSax.
809 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
810 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
811 On x86-64 and powerpc, this option can be specified
812 multiple times interleaved with hugepages= to reserve
813 huge pages of different sizes. Valid pages sizes on
814 x86-64 are 2M (when the CPU supports "pse") and 1G
815 (when the CPU supports the "pdpe1gb" cpuinfo flag)
816 Note that 1GB pages can only be allocated at boot time
817 using hugepages= and not freed afterwards.
819 [same as hugepagesz=] The size of the default
820 HugeTLB page size. This is the size represented by
821 the legacy /proc/ hugepages APIs, used for SHM, and
822 default size when mounting hugetlbfs filesystems.
823 Defaults to the default architecture's huge page size
826 i8042.direct [HW] Put keyboard port into non-translated mode
827 i8042.dumbkbd [HW] Pretend that controller can only read data from
828 keyboard and cannot control its state
829 (Don't attempt to blink the leds)
830 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
831 i8042.nokbd [HW] Don't check/create keyboard port
832 i8042.noloop [HW] Disable the AUX Loopback command while probing
834 i8042.nomux [HW] Don't check presence of an active multiplexing
836 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
839 [HW] Frequency with which keyboard LEDs should blink
840 when kernel panics (default is 0.5 sec)
841 i8042.reset [HW] Reset the controller during init and cleanup
842 i8042.unlock [HW] Unlock (ignore) the keylock
846 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
847 indicates that the driver is running on unsupported
849 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
850 does not match list of supported models.
852 [HW] Report power status in /proc/i8k
853 (disabled by default)
854 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
857 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
858 See Documentation/mca.txt.
861 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
863 ide= [HW] (E)IDE subsystem
864 Format: ide=nodma or ide=doubler
865 See Documentation/ide/ide.txt.
867 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
868 See Documentation/ide/ide.txt.
871 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
872 Poll forces a polling idle loop that can slightly improves the performance
873 of waking up a idle CPU, but will use a lot of power and make the system
874 run hot. Not recommended.
875 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
876 to not use it because it doesn't save as much power as a normal idle
877 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
879 idle=halt. Halt is forced to be used for CPU idle.
880 In such case C2/C3 won't be used again.
881 idle=nomwait. Disable mwait for CPU C-states
883 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
884 Claim all unknown PCI IDE storage controllers.
886 ignore_loglevel [KNL]
887 Ignore loglevel setting - this will print /all/
888 kernel messages to the console. Useful for debugging.
891 Set number of hash buckets for inode cache.
894 See header of drivers/scsi/in2000.c.
898 Run specified binary instead of /sbin/init as init
901 initcall_debug [KNL] Trace initcalls as they are executed. Useful
902 for working out where the kernel is dying during
905 initrd= [BOOT] Specify the location of the initial ramdisk
907 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
925 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
927 Disable intel iommu driver.
928 igfx_off [Default Off]
929 By default, gfx is mapped as normal device. If a gfx
930 device has a dedicated DMAR unit, the DMAR unit is
931 bypassed by not enabling DMAR with this option. In
932 this case, gfx device will use physical address for
935 With this option iommu will not optimize to look
936 for io virtual address below 32 bit forcing dual
937 address cycle on pci bus for cards supporting greater
938 than 32 bit addressing. The default is to look
939 for translation below 32 bit and if not available
940 then look in the higher range.
942 With this option on every unmap_single operation will
943 result in a hardware IOTLB flush operation as opposed
944 to batching them for performance.
946 io_delay= [X86-32,X86-64] I/O delay method
948 Standard port 0x80 based delay
950 Alternate port 0xed based delay (needed on some systems)
952 Simple two microseconds delay
956 io7= [HW] IO7 for Marvel based alpha systems
957 See comment before marvel_specify_io7 in
958 arch/alpha/kernel/core_marvel.c.
961 See Documentation/filesystems/nfsroot.txt.
963 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
964 See comment before ip2_setup() in
965 drivers/char/ip2/ip2base.c.
967 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
968 See header of drivers/scsi/ips.c.
970 ports= [IP_VS_FTP] IPVS ftp helper module
972 Up to 8 (IP_VS_APP_MAX_PORTS) ports
974 Format: <port>,<port>....
977 When an interrupt is not handled search all handlers
978 for it. Intended to get systems with badly broken
982 When an interrupt is not handled search all handlers
983 for it. Also check all handlers each timer
984 interrupt. Intended to get systems with badly broken
988 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
990 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
992 <cpu number>,...,<cpu number>
994 <cpu number>-<cpu number> (must be a positive range in ascending order)
996 <cpu number>,...,<cpu number>-<cpu number>
997 This option can be used to specify one or more CPUs
998 to isolate from the general SMP balancing and scheduling
999 algorithms. The only way to move a process onto or off
1000 an "isolated" CPU is via the CPU affinity syscalls.
1001 <cpu number> begins at 0 and the maximum value is
1002 "number of CPUs in system - 1".
1004 This option is the preferred way to isolate CPUs. The
1005 alternative -- manually setting the CPU mask of all
1006 tasks in the system -- can cause problems and
1007 suboptimal load balancer performance.
1011 js= [HW,JOY] Analog joystick
1012 See Documentation/input/joystick.txt.
1014 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1015 specifies the amount of memory usable by the kernel
1016 for non-movable allocations. The requested amount is
1017 spread evenly throughout all nodes in the system. The
1018 remaining memory in each node is used for Movable
1019 pages. In the event, a node is too small to have both
1020 kernelcore and Movable pages, kernelcore pages will
1021 take priority and other nodes will have a larger number
1022 of kernelcore pages. The Movable zone is used for the
1023 allocation of pages that may be reclaimed or moved
1024 by the page migration subsystem. This means that
1025 HugeTLB pages may not be allocated from this zone.
1026 Note that allocations like PTEs-from-HighMem still
1027 use the HighMem zone if it exists, and the Normal
1028 zone if it does not.
1030 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1031 is similar to kernelcore except it specifies the
1032 amount of memory used for migratable allocations.
1033 If both kernelcore and movablecore is specified,
1034 then kernelcore will be at *least* the specified
1035 value but may be more. If movablecore on its own
1036 is specified, the administrator must be careful
1037 that the amount of memory usable for all allocations
1042 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1045 kgdboc= [HW] kgdb over consoles.
1046 Requires a tty driver that supports console polling.
1047 (only serial suported for now)
1048 Format: <serial_device>[,baud]
1054 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1057 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1060 libata.dma= [LIBATA] DMA control
1061 libata.dma=0 Disable all PATA and SATA DMA
1062 libata.dma=1 PATA and SATA Disk DMA only
1063 libata.dma=2 ATAPI (CDROM) DMA only
1064 libata.dma=4 Compact Flash DMA only
1065 Combinations also work, so libata.dma=3 enables DMA
1066 for disks and CDROMs, but not CFs.
1068 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1072 libata.force= [LIBATA] Force configurations. The format is comma
1073 separated list of "[ID:]VAL" where ID is
1074 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1075 matching port, link or device. Basically, it matches
1076 the ATA ID string printed on console by libata. If
1077 the whole ID part is omitted, the last PORT and DEVICE
1078 values are used. If ID hasn't been specified yet, the
1079 configuration applies to all ports, links and devices.
1081 If only DEVICE is omitted, the parameter applies to
1082 the port and all links and devices behind it. DEVICE
1083 number of 0 either selects the first device or the
1084 first fan-out link behind PMP device. It does not
1085 select the host link. DEVICE number of 15 selects the
1086 host link and device attached to it.
1088 The VAL specifies the configuration to force. As long
1089 as there's no ambiguity shortcut notation is allowed.
1090 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1091 The following configurations can be forced.
1093 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1094 Any ID with matching PORT is used.
1096 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1098 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1099 udma[/][16,25,33,44,66,100,133] notation is also
1102 * [no]ncq: Turn on or off NCQ.
1104 * nohrst, nosrst, norst: suppress hard, soft
1107 If there are multiple matching configurations changing
1108 the same attribute, the last one is used.
1110 load_ramdisk= [RAM] List of ramdisks to load from floppy
1111 See Documentation/ramdisk.txt.
1113 lockd.nlm_grace_period=P [NFS] Assign grace period.
1116 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1119 lockd.nlm_timeout=T [NFS] Assign timeout value.
1122 lockd.nlm_udpport=M [NFS] Assign UDP port.
1125 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1128 loglevel= All Kernel Messages with a loglevel smaller than the
1129 console loglevel will be printed to the console. It can
1130 also be changed with klogd or other programs. The
1131 loglevels are defined as follows:
1133 0 (KERN_EMERG) system is unusable
1134 1 (KERN_ALERT) action must be taken immediately
1135 2 (KERN_CRIT) critical conditions
1136 3 (KERN_ERR) error conditions
1137 4 (KERN_WARNING) warning conditions
1138 5 (KERN_NOTICE) normal but significant condition
1139 6 (KERN_INFO) informational
1140 7 (KERN_DEBUG) debug-level messages
1142 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1143 Format: { n | nk | nM }
1144 n must be a power of two. The default size
1145 is set in the kernel config file.
1147 logo.nologo [FB] Disables display of the built-in Linux logo.
1148 This may be used to provide more screen space for
1149 kernel log messages and is useful when debugging
1150 kernel boot problems.
1152 lp=0 [LP] Specify parallel ports to use, e.g,
1153 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1154 lp=reset first parallel port). 'lp=0' disables the
1155 lp=auto printer driver. 'lp=reset' (which can be
1156 specified in addition to the ports) causes
1157 attached printers to be reset. Using
1158 lp=port1,port2,... specifies the parallel ports
1159 to associate lp devices with, starting with
1160 lp0. A port specification may be 'none' to skip
1161 that lp device, or a parport name such as
1162 'parport0'. Specifying 'lp=auto' instead of a
1163 port specification list means that device IDs
1164 from each port should be examined, to see if
1165 an IEEE 1284-compliant printer is attached; if
1166 so, the driver will manage that printer.
1167 See also header of drivers/char/lp.c.
1170 Sets loops_per_jiffy to given constant, thus avoiding
1171 time-consuming boot-time autodetection (up to 250 ms per
1172 CPU). 0 enables autodetection (default). To determine
1173 the correct value for your kernel, boot with normal
1174 autodetection and see what value is printed. Note that
1175 on SMP systems the preset will be applied to all CPUs,
1176 which is likely to cause problems if your CPUs need
1177 significantly divergent settings. An incorrect value
1178 will cause delays in the kernel to be wrong, leading to
1179 unpredictable I/O errors and other breakage. Although
1180 unlikely, in the extreme case this might damage your
1184 Format: <io>,<irq>,<dma>
1186 mac5380= [HW,SCSI] Format:
1187 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1189 machvec= [IA64] Force the use of a particular machine-vector
1190 (machvec) in a generic kernel.
1191 Example: machvec=hpzx1_swiotlb
1193 max_loop= [LOOP] Maximum number of loopback devices that can
1197 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1198 should make use of. maxcpus=n : n >= 0 limits the
1199 kernel to using 'n' processors. n=0 is a special case,
1200 it is equivalent to "nosmp", which also disables
1203 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1204 equal to this physical address is ignored.
1206 max_luns= [SCSI] Maximum number of LUNs to probe.
1207 Should be between 1 and 2^32-1.
1210 [SCSI] Maximum number of LUNs received.
1211 Should be between 1 and 16384.
1215 mce [X86-32] Machine Check Exception
1217 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1219 md= [HW] RAID subsystems devices and level
1220 See Documentation/md.txt.
1223 Format: <first>,<last>
1224 Specifies range of consoles to be captured by the MDA.
1226 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1227 Amount of memory to be used when the kernel is not able
1228 to see the whole system memory or for test.
1229 [X86-32] Use together with memmap= to avoid physical
1230 address space collisions. Without memmap= PCI devices
1231 could be placed at addresses belonging to unused RAM.
1233 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1236 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1237 E820 memory map, as specified by the user.
1238 Such memmap=exactmap lines can be constructed based on
1239 BIOS output or other requirements. See the memmap=nn@ss
1242 memmap=nn[KMG]@ss[KMG]
1243 [KNL] Force usage of a specific region of memory
1244 Region of memory to be used, from ss to ss+nn.
1246 memmap=nn[KMG]#ss[KMG]
1247 [KNL,ACPI] Mark specific memory as ACPI data.
1248 Region of memory to be used, from ss to ss+nn.
1250 memmap=nn[KMG]$ss[KMG]
1251 [KNL,ACPI] Mark specific memory as reserved.
1252 Region of memory to be used, from ss to ss+nn.
1253 Example: Exclude memory from 0x18690000-0x1869ffff
1254 memmap=64K$0x18690000
1256 memmap=0x10000$0x18690000
1258 memtest= [KNL,X86] Enable memtest
1260 range: 0,4 : pattern number
1261 default : 0 <disable>
1263 meye.*= [HW] Set MotionEye Camera parameters
1264 See Documentation/video4linux/meye.txt.
1266 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1267 Multi-Function General Purpose Timers on AMD Geode
1270 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1271 the BIOS has incorrectly applied a workaround. TinyBIOS
1272 version 0.98 is known to be affected, 0.99 fixes the
1273 problem by letting the user disable the workaround.
1278 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1279 parameter allows control of the logging verbosity for
1280 the additional memory initialisation checks. A value
1281 of 0 disables mminit logging and a level of 4 will
1282 log everything. Information is printed at KERN_DEBUG
1283 so loglevel=8 may also need to be specified.
1286 [MOUSE] Maximum time between finger touching and
1287 leaving touchpad surface for touch to be considered
1288 a tap and be reported as a left button click (for
1289 touchpads working in absolute mode only).
1291 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1292 reporting absolute coordinates, such as tablets
1293 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1294 reporting absolute coordinates, such as tablets
1299 MTD_Partition= [MTD]
1300 Format: <name>,<region-number>,<size>,<offset>
1302 MTD_Region= [MTD] Format:
1303 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1306 See drivers/mtd/cmdlinepart.c.
1309 ARM/S3C2412 JIVE boot control
1311 See arch/arm/mach-s3c2412/mach-jive.c
1313 mtouchusb.raw_coordinates=
1314 [HW] Make the MicroTouch USB driver use raw coordinates
1315 ('y', default) or cooked coordinates ('n')
1317 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1320 See header of drivers/scsi/NCR_D700.c.
1324 ncr53c400= [HW,SCSI]
1326 ncr53c400a= [HW,SCSI]
1328 ncr53c406a= [HW,SCSI]
1330 ncr53c8xx= [HW,SCSI]
1332 netdev= [NET] Network devices parameters
1333 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1334 Note that mem_start is often overloaded to mean
1335 something different and driver-specific.
1336 This usage is only documented in each driver source
1340 [NETFILTER] Enable connection tracking flow accounting
1341 0 to disable accounting
1342 1 to enable accounting
1343 Default value depends on CONFIG_NF_CT_ACCT that is
1344 going to be removed in 2.6.29.
1347 See Documentation/filesystems/nfsroot.txt.
1349 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1350 See Documentation/filesystems/nfsroot.txt.
1352 nfs.callback_tcpport=
1353 [NFS] set the TCP port on which the NFSv4 callback
1354 channel should listen.
1356 nfs.idmap_cache_timeout=
1357 [NFS] set the maximum lifetime for idmapper cache
1361 [NFS] enable 64-bit inode numbers.
1362 If zero, the NFS client will fake up a 32-bit inode
1363 number for the readdir() and stat() syscalls instead
1364 of returning the full 64-bit number.
1365 The default is to return 64-bit inode numbers.
1367 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1368 when a NMI is triggered.
1369 Format: [state][,regs][,debounce][,die]
1371 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1373 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1374 emulation library even if a 387 maths coprocessor
1377 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1378 caches in the slab allocator. Saves per-node memory,
1379 but will impact performance.
1383 noapic [SMP,APIC] Tells the kernel to not make use of any
1384 IOAPICs that may be present in the system.
1386 nobats [PPC] Do not use BATs for mapping kernel lowmem
1387 on "Classic" PPC cores.
1391 nodelayacct [KNL] Disable per-task delay accounting
1393 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1395 noefi [X86-32,X86-64] Disable EFI runtime services support.
1399 noexec [X86-32,X86-64]
1400 On X86-32 available only on PAE configured kernels.
1401 noexec=on: enable non-executable mappings (default)
1402 noexec=off: disable non-executable mappings
1405 This affects only 32-bit executables.
1406 noexec32=on: enable non-executable mappings (default)
1407 read doesn't imply executable mappings
1408 noexec32=off: disable non-executable mappings
1409 read implies executable mappings
1411 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1412 register save and restore. The kernel will only save
1413 legacy floating-point registers on task switch.
1415 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1419 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1420 instruction doesn't work correctly and not to
1423 nohalt [IA-64] Tells the kernel not to use the power saving
1424 function PAL_HALT_LIGHT when idle. This increases
1425 power-consumption. On the positive side, it reduces
1426 interrupt wake-up latency, which may improve performance
1427 in certain environments such as networked servers or
1430 nohz= [KNL] Boottime enable/disable dynamic ticks
1431 Valid arguments: on, off
1434 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1436 noirqdebug [X86-32] Disables the code which attempts to detect and
1437 disable unhandled interrupt sources.
1439 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1440 broken timer IRQ sources.
1442 noisapnp [ISAPNP] Disables ISA PnP code.
1444 noinitrd [RAM] Tells the kernel not to load any configured
1449 nojitter [IA64] Disables jitter checking for ITC timers.
1451 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1453 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1455 noltlbs [PPC] Do not use large page/tlb entries for kernel
1456 lowmem mapping on PPC40x.
1458 nomca [IA-64] Disable machine check abort handling
1460 nomce [X86-32] Machine Check Exception
1462 nomfgpt [X86-32] Disable Multi-Function General Purpose
1463 Timer usage (for AMD Geode machines).
1465 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1467 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1468 with UP alternatives
1470 noresidual [PPC] Don't use residual data on PReP machines.
1472 noresume [SWSUSP] Disables resume and restores original swap
1475 no-scroll [VGA] Disables scrollback.
1476 This is required for the Braillex ib80-piezo Braille
1477 reader made by F.H. Papenmeier (Germany).
1481 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1483 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1484 and disable the IO APIC. legacy for "maxcpus=0".
1486 nosoftlockup [KNL] Disable the soft-lockup detector.
1488 nosync [HW,M68K] Disables sync negotiation for all devices.
1490 notsc [BUGS=X86-32] Disable Time Stamp Counter
1492 nousb [USB] Disable the USB subsystem
1496 nptcg= [IA64] Override max number of concurrent global TLB
1497 purges which is reported from either PAL_VM_SUMMARY or
1500 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1501 one of ['zone', 'node', 'default'] can be specified
1502 This can be set from sysctl after boot.
1503 See Documentation/sysctl/vm.txt for details.
1505 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1507 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1508 Rather than timing out after 20 ms if an EC
1509 command is not properly ACKed, override the length
1510 of the timeout. We have interrupts disabled while
1511 waiting for the ACK, so if this is set too high
1512 interrupts *may* be lost!
1517 oprofile.timer= [HW]
1518 Use timer interrupt instead of performance counters
1520 osst= [HW,SCSI] SCSI Tape Driver
1521 Format: <buffer_size>,<write_threshold>
1522 See also Documentation/scsi/st.txt.
1524 panic= [KNL] Kernel behaviour on panic
1527 parkbd.port= [HW] Parallel port number the keyboard adapter is
1528 connected to, default is 0.
1530 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1531 0 for XT, 1 for AT (default is AT).
1534 parport= [HW,PPT] Specify parallel ports. 0 disables.
1535 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1536 Use 'auto' to force the driver to use any
1537 IRQ/DMA settings detected (the default is to
1538 ignore detected IRQ/DMA settings because of
1539 possible conflicts). You can specify the base
1540 address, IRQ, and DMA settings; IRQ and DMA
1541 should be numbers, or 'auto' (for using detected
1542 settings on that particular port), or 'nofifo'
1543 (to avoid using a FIFO even if it is detected).
1544 Parallel ports are assigned in the order they
1545 are specified on the command line, starting
1548 parport_init_mode= [HW,PPT]
1549 Configure VIA parallel port to operate in
1550 a specific mode. This is necessary on Pegasos
1551 computer where firmware has no options for setting
1552 up parallel port mode and sets it to spp.
1553 Currently this function knows 686a and 8231 chips.
1554 Format: [spp|ps2|epp|ecp|ecpepp]
1556 pas2= [HW,OSS] Format:
1557 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1560 See header of drivers/scsi/pas16.c.
1563 Halt all CPUs after the first oops has been printed for
1564 the specified number of seconds. This is to be used if
1565 your oopses keep scrolling off the screen.
1570 See header of drivers/block/paride/pcd.c.
1571 See also Documentation/paride.txt.
1573 pci=option[,option...] [PCI] various PCI subsystem options:
1574 off [X86-32] don't probe for the PCI bus
1575 bios [X86-32] force use of PCI BIOS, don't access
1576 the hardware directly. Use this if your machine
1577 has a non-standard PCI host bridge.
1578 nobios [X86-32] disallow use of PCI BIOS, only direct
1579 hardware access methods are allowed. Use this
1580 if you experience crashes upon bootup and you
1581 suspect they are caused by the BIOS.
1582 conf1 [X86-32] Force use of PCI Configuration
1584 conf2 [X86-32] Force use of PCI Configuration
1586 noaer [PCIE] If the PCIEAER kernel config parameter is
1587 enabled, this kernel boot option can be used to
1588 disable the use of PCIE advanced error reporting.
1589 nodomains [PCI] Disable support for multiple PCI
1590 root domains (aka PCI segments, in ACPI-speak).
1591 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1593 nomsi [MSI] If the PCI_MSI kernel config parameter is
1594 enabled, this kernel boot option can be used to
1595 disable the use of MSI interrupts system-wide.
1596 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1597 routing table. These calls are known to be buggy
1598 on several machines and they hang the machine
1599 when used, but on other computers it's the only
1600 way to get the interrupt routing table. Try
1601 this option if the kernel is unable to allocate
1602 IRQs or discover secondary PCI buses on your
1604 rom [X86-32] Assign address space to expansion ROMs.
1605 Use with caution as certain devices share
1606 address decoders between ROMs and other
1608 norom [X86-32,X86_64] Do not assign address space to
1609 expansion ROMs that do not already have
1610 BIOS assigned address ranges.
1611 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1612 assigned automatically to PCI devices. You can
1613 make the kernel exclude IRQs of your ISA cards
1615 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1616 of the PIRQ table (normally generated
1617 by the BIOS) if it is outside the
1618 F0000h-100000h range.
1619 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1620 useful if the kernel is unable to find your
1621 secondary buses and you want to tell it
1622 explicitly which ones they are.
1623 assign-busses [X86-32] Always assign all PCI bus
1624 numbers ourselves, overriding
1625 whatever the firmware may have done.
1626 usepirqmask [X86-32] Honor the possible IRQ mask stored
1627 in the BIOS $PIR table. This is needed on
1628 some systems with broken BIOSes, notably
1629 some HP Pavilion N5400 and Omnibook XE3
1630 notebooks. This will have no effect if ACPI
1631 IRQ routing is enabled.
1632 noacpi [X86-32] Do not use ACPI for IRQ routing
1633 or for PCI scanning.
1634 use_crs [X86-32] Use _CRS for PCI resource
1636 routeirq Do IRQ routing for all PCI devices.
1637 This is normally done in pci_enable_device(),
1638 so this option is a temporary workaround
1639 for broken drivers that don't call it.
1640 skip_isa_align [X86] do not align io start addr, so can
1641 handle more pci cards
1642 firmware [ARM] Do not re-enumerate the bus but instead
1643 just use the configuration from the
1644 bootloader. This is currently used on
1645 IXP2000 systems where the bus has to be
1646 configured a certain way for adjunct CPUs.
1647 noearly [X86] Don't do any early type 1 scanning.
1648 This might help on some broken boards which
1649 machine check when some devices' config space
1650 is read. But various workarounds are disabled
1651 and some IOMMU drivers will not work.
1652 bfsort Sort PCI devices into breadth-first order.
1653 This sorting is done to get a device
1654 order compatible with older (<= 2.4) kernels.
1655 nobfsort Don't sort PCI devices into breadth-first order.
1656 cbiosize=nn[KMG] The fixed amount of bus space which is
1657 reserved for the CardBus bridge's IO window.
1658 The default value is 256 bytes.
1659 cbmemsize=nn[KMG] The fixed amount of bus space which is
1660 reserved for the CardBus bridge's memory
1661 window. The default value is 64 megabytes.
1663 pcmv= [HW,PCMCIA] BadgePAD 4
1666 See Documentation/paride.txt.
1668 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1671 See arch/parisc/kernel/pdc_chassis.c
1674 See Documentation/paride.txt.
1677 See Documentation/paride.txt.
1679 pirq= [SMP,APIC] Manual mp-table setup
1680 See Documentation/i386/IO-APIC.txt.
1682 plip= [PPT,NET] Parallel port network link
1683 Format: { parport<nr> | timid | 0 }
1684 See also Documentation/parport.txt.
1686 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1687 Override pmtimer IOPort with a hex value.
1694 { on | off | curr | res | no-curr | no-res }
1697 [ISAPNP] Exclude IRQs for the autoconfiguration
1700 [ISAPNP] Exclude DMAs for the autoconfiguration
1702 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1703 Ranges are in pairs (I/O port base and size).
1706 [ISAPNP] Exclude memory regions for the
1708 Ranges are in pairs (memory base and size).
1710 print-fatal-signals=
1711 [KNL] debug: print fatal signals
1712 print-fatal-signals=1: print segfault info to
1716 printk.time= Show timing data prefixed to each printk message line
1717 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1719 profile= [KNL] Enable kernel profiling via /proc/profile
1720 Format: [schedule,]<number>
1721 Param: "schedule" - profile schedule points.
1722 Param: <number> - step/bucket size as a power of 2 for
1723 statistical time based profiling.
1724 Param: "sleep" - profile D-state sleeping (millisecs).
1725 Requires CONFIG_SCHEDSTATS
1726 Param: "kvm" - profile VM exits.
1728 processor.max_cstate= [HW,ACPI]
1729 Limit processor to maximum C-state
1730 max_cstate=9 overrides any DMI blacklist limit.
1732 processor.nocst [HW,ACPI]
1733 Ignore the _CST method to determine C-states,
1734 instead using the legacy FADT method
1736 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1738 See Documentation/ramdisk.txt.
1740 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1741 probe for; one of (bare|imps|exps|lifebook|any).
1742 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1744 psmouse.resetafter= [HW,MOUSE]
1745 Try to reset the device after so many bad packets
1748 [HW,MOUSE] Set desired mouse resolution, in dpi.
1749 psmouse.smartscroll=
1750 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1751 0 = disabled, 1 = enabled (default).
1753 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1755 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1758 See Documentation/paride.txt.
1761 [KNL] Number of legacy pty's. Overwrites compiled-in
1764 quiet [KNL] Disable most log messages
1769 See Documentation/md.txt.
1771 ramdisk_blocksize= [RAM]
1772 See Documentation/ramdisk.txt.
1774 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1775 See Documentation/ramdisk.txt.
1777 rcupdate.blimit= [KNL,BOOT]
1778 Set maximum number of finished RCU callbacks to process
1781 rcupdate.qhimark= [KNL,BOOT]
1782 Set threshold of queued
1783 RCU callbacks over which batch limiting is disabled.
1785 rcupdate.qlowmark= [KNL,BOOT]
1786 Set threshold of queued RCU callbacks below which
1787 batch limiting is re-enabled.
1791 Run specified binary instead of /init from the ramdisk,
1792 used for early userspace startup. See initrd.
1794 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1795 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1796 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1799 [KNL, SMP] Set scheduler's default relax_domain_level.
1800 See Documentation/cpusets.txt.
1802 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1804 reservetop= [X86-32]
1806 Reserves a hole at the top of the kernel virtual
1809 reset_devices [KNL] Force drivers to reset the underlying device
1810 during initialization.
1813 Specify the partition device for software suspend
1815 resume_offset= [SWSUSP]
1816 Specify the offset from the beginning of the partition
1817 given by "resume=" at which the swap header is located,
1818 in <PAGE_SIZE> units (needed only for swap files).
1819 See Documentation/power/swsusp-and-swap-files.txt
1821 retain_initrd [RAM] Keep initrd memory after extraction
1823 rhash_entries= [KNL,NET]
1824 Set number of hash buckets for route cache
1826 riscom8= [HW,SERIAL]
1827 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1829 ro [KNL] Mount root device read-only on boot
1831 root= [KNL] Root filesystem
1833 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1834 mount the root filesystem
1836 rootflags= [KNL] Set root filesystem mount option string
1838 rootfstype= [KNL] Set root filesystem type
1840 rootwait [KNL] Wait (indefinitely) for root device to show up.
1841 Useful for devices that are detected asynchronously
1842 (e.g. USB and MMC devices).
1844 root_plug.vendor_id=
1845 [ROOTPLUG] Override the default vendor ID
1847 root_plug.product_id=
1848 [ROOTPLUG] Override the default product ID
1851 [ROOTPLUG] Enable debugging output
1853 rw [KNL] Mount root device read-write on boot
1855 S [KNL] Run init in single mode
1858 See drivers/net/irda/sa1100_ir.c.
1860 sbni= [NET] Granch SBNI12 leased line adapter
1862 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1863 Format: <io>[,<timeout>[,<isapnp>]]
1865 scsi_debug_*= [SCSI]
1866 See drivers/scsi/scsi_debug.c.
1868 scsi_default_dev_flags=
1869 [SCSI] SCSI default device flags
1872 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1873 Format: <vendor>:<model>:<flags>
1874 (flags are integer value)
1876 scsi_logging_level= [SCSI] a bit mask of logging levels
1877 See drivers/scsi/scsi_logging.h for bits. Also
1878 settable via sysctl at dev.scsi.logging_level
1879 (/proc/sys/dev/scsi/logging_level).
1880 There is also a nice 'scsi_logging_level' script in the
1881 S390-tools package, available for download at
1882 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1884 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1885 discovered. async scans them in kernel threads,
1886 allowing boot to proceed. none ignores them, expecting
1887 user space to do the scan.
1889 selinux [SELINUX] Disable or enable SELinux at boot time.
1890 Format: { "0" | "1" }
1891 See security/selinux/Kconfig help text.
1894 Default value is set via kernel config option.
1895 If enabled at boot time, /selinux/disable can be used
1896 later to disable prior to initial policy load.
1898 selinux_compat_net =
1899 [SELINUX] Set initial selinux_compat_net flag value.
1900 Format: { "0" | "1" }
1901 0 -- use new secmark-based packet controls
1902 1 -- use legacy packet controls
1903 Default value is 0 (preferred).
1904 Value can be changed at runtime via
1905 /selinux/compat_net.
1907 serialnumber [BUGS=X86-32]
1910 Maximal number of shapers.
1913 See header of drivers/scsi/sim710.c.
1920 slub_debug[=options[,slabs]] [MM, SLUB]
1921 Enabling slub_debug allows one to determine the
1922 culprit if slab objects become corrupted. Enabling
1923 slub_debug can create guard zones around objects and
1924 may poison objects when not in use. Also tracks the
1925 last alloc / free. For more information see
1926 Documentation/vm/slub.txt.
1928 slub_max_order= [MM, SLUB]
1929 Determines the maximum allowed order for slabs.
1930 A high setting may cause OOMs due to memory
1931 fragmentation. For more information see
1932 Documentation/vm/slub.txt.
1934 slub_min_objects= [MM, SLUB]
1935 The minimum number of objects per slab. SLUB will
1936 increase the slab order up to slub_max_order to
1937 generate a sufficiently large slab able to contain
1938 the number of objects indicated. The higher the number
1939 of objects the smaller the overhead of tracking slabs
1940 and the less frequently locks need to be acquired.
1941 For more information see Documentation/vm/slub.txt.
1943 slub_min_order= [MM, SLUB]
1944 Determines the mininum page order for slabs. Must be
1945 lower than slub_max_order.
1946 For more information see Documentation/vm/slub.txt.
1948 slub_nomerge [MM, SLUB]
1949 Disable merging of slabs with similar size. May be
1950 necessary if there is some reason to distinguish
1951 allocs to different slabs. Debug options disable
1952 merging on their own.
1953 For more information see Documentation/vm/slub.txt.
1956 Format: <io1>[,<io2>[,...,<io8>]]
1958 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1959 attempt to substitute SMP alternatives once at boot.
1961 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1962 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1963 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1964 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1965 smsc-ircc2.ircc_irq= [HW] IRQ line
1966 smsc-ircc2.ircc_dma= [HW] DMA channel
1967 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1968 0: Toshiba Satellite 1800 (GP data pin select)
1969 1: Fast pin select (default)
1972 snd-ad1816a= [HW,ALSA]
1974 snd-ad1848= [HW,ALSA]
1976 snd-ali5451= [HW,ALSA]
1978 snd-als100= [HW,ALSA]
1980 snd-als4000= [HW,ALSA]
1982 snd-azt2320= [HW,ALSA]
1984 snd-cmi8330= [HW,ALSA]
1986 snd-cmipci= [HW,ALSA]
1988 snd-cs4231= [HW,ALSA]
1990 snd-cs4232= [HW,ALSA]
1992 snd-cs4236= [HW,ALSA]
1994 snd-cs4281= [HW,ALSA]
1996 snd-cs46xx= [HW,ALSA]
1998 snd-dt019x= [HW,ALSA]
2000 snd-dummy= [HW,ALSA]
2002 snd-emu10k1= [HW,ALSA]
2004 snd-ens1370= [HW,ALSA]
2006 snd-ens1371= [HW,ALSA]
2008 snd-es968= [HW,ALSA]
2010 snd-es1688= [HW,ALSA]
2012 snd-es18xx= [HW,ALSA]
2014 snd-es1938= [HW,ALSA]
2016 snd-es1968= [HW,ALSA]
2018 snd-fm801= [HW,ALSA]
2020 snd-gusclassic= [HW,ALSA]
2022 snd-gusextreme= [HW,ALSA]
2024 snd-gusmax= [HW,ALSA]
2028 snd-ice1712= [HW,ALSA]
2030 snd-intel8x0= [HW,ALSA]
2032 snd-interwave= [HW,ALSA]
2037 snd-korg1212= [HW,ALSA]
2039 snd-maestro3= [HW,ALSA]
2041 snd-mpu401= [HW,ALSA]
2043 snd-mtpav= [HW,ALSA]
2045 snd-nm256= [HW,ALSA]
2047 snd-opl3sa2= [HW,ALSA]
2055 snd-opti93x= [HW,ALSA]
2059 snd-rme32= [HW,ALSA]
2061 snd-rme96= [HW,ALSA]
2063 snd-rme9652= [HW,ALSA]
2069 snd-sbawe= [HW,ALSA]
2071 snd-serial= [HW,ALSA]
2073 snd-sgalaxy= [HW,ALSA]
2075 snd-sonicvibes= [HW,ALSA]
2080 snd-sun-cs4231= [HW,ALSA]
2082 snd-trident= [HW,ALSA]
2084 snd-usb-audio= [HW,ALSA,USB]
2086 snd-via82xx= [HW,ALSA]
2088 snd-virmidi= [HW,ALSA]
2090 snd-wavefront= [HW,ALSA]
2092 snd-ymfpci= [HW,ALSA]
2095 [KNL] Should the soft-lockup detector generate panics.
2097 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2098 See Documentation/sonypi.txt
2100 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2101 See Documentation/specialix.txt.
2103 spia_io_base= [HW,MTD]
2109 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2111 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2112 See Documentation/scsi/st.txt.
2116 Set the STI (builtin display/keyboard on the HP-PARISC
2117 machines) console (graphic card) which should be used
2118 as the initial boot-console.
2119 See also comment in drivers/video/console/sticore.c.
2122 See comment in drivers/video/console/sticore.c.
2125 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2129 Control how the NFS server code allocates CPUs to
2130 service thread pools. Depending on how many NICs
2131 you have and where their interrupts are bound, this
2132 option will affect which CPUs will do NFS serving.
2133 Note: this parameter cannot be changed while the
2134 NFS server is running.
2136 auto the server chooses an appropriate mode
2137 automatically using heuristics
2138 global a single global pool contains all CPUs
2139 percpu one pool for each CPU
2140 pernode one pool for each NUMA node (equivalent
2141 to global on non-NUMA machines)
2143 swiotlb= [IA-64] Number of I/O TLB slabs
2147 sym53c416= [HW,SCSI]
2148 See header of drivers/scsi/sym53c416.c.
2150 sysrq_always_enabled
2152 Ignore sysrq setting - this boot parameter will
2153 neutralize any effect of /proc/sys/kernel/sysrq.
2154 Useful for debugging.
2157 See header of drivers/scsi/t128.c.
2161 test_suspend= [SUSPEND]
2162 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2163 standby suspend) as the system sleep state to briefly
2164 enter during system startup. The system is woken from
2165 this state using a wakeup-capable RTC alarm.
2167 thash_entries= [KNL,NET]
2168 Set number of hash buckets for TCP connection
2170 thermal.act= [HW,ACPI]
2171 -1: disable all active trip points in all thermal zones
2172 <degrees C>: override all lowest active trip points
2174 thermal.crt= [HW,ACPI]
2175 -1: disable all critical trip points in all thermal zones
2176 <degrees C>: lower all critical trip points
2178 thermal.nocrt= [HW,ACPI]
2179 Set to disable actions on ACPI thermal zone
2180 critical and hot trip points.
2182 thermal.off= [HW,ACPI]
2183 1: disable ACPI thermal control
2185 thermal.psv= [HW,ACPI]
2186 -1: disable all passive trip points
2187 <degrees C>: override all passive trip points to this value
2189 thermal.tzp= [HW,ACPI]
2190 Specify global default ACPI thermal zone polling rate
2191 <deci-seconds>: poll all this frequency
2192 0: no polling (default)
2195 See comment before function dc390_setup() in
2196 drivers/scsi/tmscsim.c.
2200 trix= [HW,OSS] MediaTrix AudioTrix Pro
2202 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2204 turbografx.map[2|3]= [HW,JOY]
2205 TurboGraFX parallel port interface
2207 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2208 See also Documentation/input/joystick-parport.txt
2210 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2211 See header of drivers/scsi/u14-34f.c.
2220 [USB] Ignore overcurrent events (default N).
2221 Some badly-designed motherboards generate lots of
2222 bogus events, for ports that aren't wired to
2223 anything. Set this parameter to avoid log spamming.
2224 Note that genuine overcurrent events won't be
2229 Set unknown_nmi_panic=1 early on boot.
2231 usbcore.autosuspend=
2232 [USB] The autosuspend time delay (in seconds) used
2233 for newly-detected USB devices (default 2). This
2234 is the time required before an idle device will be
2235 autosuspended. Devices for which the delay is set
2236 to a negative value won't be autosuspended at all.
2239 [USBHID] The interval which mice are to be polled at.
2241 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2242 kernel's map of available physical RAM.
2244 vdso= [X86-32,SH,x86-64]
2245 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2246 vdso=1: enable VDSO (default)
2247 vdso=0: disable VDSO mapping
2249 vdso32= [X86-32,X86-64]
2250 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2251 vdso32=1: enable 32-bit VDSO (default)
2252 vdso32=0: disable 32-bit VDSO mapping
2255 vector=percpu: enable percpu vector domain
2257 video= [FB] Frame buffer configuration
2258 See Documentation/fb/modedb.txt.
2260 vga= [BOOT,X86-32] Select a particular video mode
2261 See Documentation/i386/boot.txt and
2262 Documentation/svga.txt.
2263 Use vga=ask for menu.
2264 This is actually a boot loader parameter; the value is
2265 passed to the kernel using a special protocol.
2267 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2268 size of <nn>. This can be used to increase the
2269 minimum size (128MB on x86). It can also be used to
2270 decrease the size and leave more room for directly
2273 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2276 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2279 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2282 waveartist= [HW,OSS]
2283 Format: <io>,<irq>,<dma>,<dma2>
2286 See header of drivers/scsi/wd33c93.c.
2289 See header of drivers/scsi/wd7000.c.
2292 See Documentation/watchdog/wdt.txt.
2294 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2295 xd_geo= See header of drivers/block/xd.c.
2297 xirc2ps_cs= [NET,PCMCIA]
2299 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2301 norandmaps Don't use address space randomization
2302 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2304 ______________________________________________________________________
2308 Add documentation for ALSA options.
2309 Add more DRM drivers.