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 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/power/pm.txt, pci=noacpi
143 acpi_apic_instance= [ACPI, IOAPIC]
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
149 acpi_sleep= [HW,ACPI] Sleep options
150 Format: { s3_bios, s3_mode, s3_beep, old_ordering }
151 See Documentation/power/video.txt for s3_bios and s3_mode.
152 s3_beep is for debugging; it makes the PC's speaker beep
153 as soon as the kernel's real-mode entry point is called.
154 old_ordering causes the ACPI 1.0 ordering of the _PTS
155 control method, wrt putting devices into low power
156 states, to be enforced (the ACPI 2.0 ordering of _PTS is
159 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
160 Format: { level | edge | high | low }
162 acpi_irq_balance [HW,ACPI]
163 ACPI will balance active IRQs
166 acpi_irq_nobalance [HW,ACPI]
167 ACPI will not move active IRQs (default)
170 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
172 Format: <irq>,<irq>...
174 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
175 Format: <irq>,<irq>...
177 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
179 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
180 Format: To spoof as Windows 98: ="Microsoft Windows"
182 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
183 acpi_osi="string1" # add string1 -- only one string
184 acpi_osi="!string2" # remove built-in string2
185 acpi_osi= # disable all strings
187 acpi_serialize [HW,ACPI] force serialization of AML methods
189 acpi_skip_timer_override [HW,ACPI]
190 Recognize and ignore IRQ0/pin2 Interrupt Override.
191 For broken nForce2 BIOS resulting in XT-PIC timer.
192 acpi_use_timer_override [HW,ACPI}
193 Use timer override. For some broken Nvidia NF5 boards
194 that require a timer override, but don't have
197 acpi.debug_layer= [HW,ACPI]
199 Each bit of the <int> indicates an ACPI debug layer,
200 1: enable, 0: disable. It is useful for boot time
201 debugging. After system has booted up, it can be set
202 via /sys/module/acpi/parameters/debug_layer.
203 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
204 Available bits (add the numbers together) to enable debug output
205 for specific parts of the ACPI subsystem:
206 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
207 0x10 namespace 0x20 parser 0x40 dispatcher
208 0x80 executer 0x100 resources 0x200 acpica debugger
209 0x400 os services 0x800 acpica disassembler.
210 The number can be in decimal or prefixed with 0x in hex.
211 Warning: Many of these options can produce a lot of
212 output and make your system unusable. Be very careful.
214 acpi.debug_level= [HW,ACPI]
216 Each bit of the <int> indicates an ACPI debug level,
217 1: enable, 0: disable. It is useful for boot time
218 debugging. After system has booted up, it can be set
219 via /sys/module/acpi/parameters/debug_level.
220 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
221 Available bits (add the numbers together) to enable different
222 debug output levels of the ACPI subsystem:
223 0x01 error 0x02 warn 0x04 init 0x08 debug object
224 0x10 info 0x20 init names 0x40 parse 0x80 load
225 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
226 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
227 0x10000 resources 0x20000 user requests 0x40000 package.
228 The number can be in decimal or prefixed with 0x in hex.
229 Warning: Many of these options can produce a lot of
230 output and make your system unusable. Be very careful.
232 acpi_pm_good [X86-32,X86-64]
233 Override the pmtimer bug detection: force the kernel
234 to assume that this machine's pmtimer latches its value
235 and always returns good values.
238 { off | try_unsupported }
239 off: disable AGP support
240 try_unsupported: try to drive unsupported chipsets
241 (may crash computer or cause data corruption)
243 enable_timer_pin_1 [i386,x86-64]
244 Enable PIN 1 of APIC timer
245 Can be useful to work around chipset bugs
246 (in particular on some ATI chipsets).
247 The kernel tries to set a reasonable default.
249 disable_timer_pin_1 [i386,x86-64]
250 Disable PIN 1 of APIC timer
251 Can be useful to work around chipset bugs.
254 Format: <io>,<irq>,<dma>,<dma2>,<type>
257 See header of drivers/scsi/advansys.c.
259 advwdt= [HW,WDT] Advantech WDT
260 Format: <iostart>,<iostop>
262 aedsp16= [HW,OSS] Audio Excel DSP 16
263 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
264 See also header of sound/oss/aedsp16.c.
267 See Documentation/scsi/aha152x.txt.
270 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
273 See Documentation/scsi/aic7xxx.txt.
276 See Documentation/scsi/aic79xx.txt.
278 amd_iommu= [HW,X86-84]
279 Pass parameters to the AMD IOMMU driver in the system.
281 isolate - enable device isolation (each device, as far
282 as possible, will get its own protection
284 amd_iommu_size= [HW,X86-64]
285 Define the size of the aperture for the AMD IOMMU
286 driver. Possible values are:
287 '32M', '64M' (default), '128M', '256M', '512M', '1G'
289 amijoy.map= [HW,JOY] Amiga joystick support
290 Map of devices attached to JOY0DAT and JOY1DAT
292 See also Documentation/kernel/input/joystick.txt
294 analog.map= [HW,JOY] Analog joystick and gamepad support
295 Specifies type or capabilities of an analog joystick
296 connected to one of 16 gameports
297 Format: <type1>,<type2>,..<type16>
300 Power management functions (SPARCstation-4/5 + deriv.)
302 Disable APC CPU standby support. SPARCstation-Fox does
303 not play well with APC CPU idle - disable it if you have
304 APC and your system crashes randomly.
306 apic= [APIC,i386] Advanced Programmable Interrupt Controller
307 Change the output verbosity whilst booting
308 Format: { quiet (default) | verbose | debug }
309 Change the amount of debugging information output
310 when initialising the APIC and IO-APIC components.
312 apm= [APM] Advanced Power Management
313 See header of arch/x86/kernel/apm_32.c.
315 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
316 Format: <io>,<irq>,<nodeID>
320 atarimouse= [HW,MOUSE] Atari Mouse
322 atascsi= [HW,SCSI] Atari SCSI
324 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
325 EzKey and similar keyboards
327 atkbd.reset= [HW] Reset keyboard during initialization
329 atkbd.set= [HW] Select keyboard code set
330 Format: <int> (2 = AT (default), 3 = PS/2)
332 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
335 atkbd.softraw= [HW] Choose between synthetic and real raw mode
336 Format: <bool> (0 = real, 1 = synthetic (default))
338 atkbd.softrepeat= [HW]
339 Use software keyboard repeat
343 baycom_epp= [HW,AX25]
346 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
348 See header of drivers/net/hamradio/baycom_par.c.
350 baycom_ser_fdx= [HW,AX25]
351 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
352 Format: <io>,<irq>,<mode>[,<baud>]
353 See header of drivers/net/hamradio/baycom_ser_fdx.c.
355 baycom_ser_hdx= [HW,AX25]
356 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
357 Format: <io>,<irq>,<mode>
358 See header of drivers/net/hamradio/baycom_ser_hdx.c.
360 boot_delay= Milliseconds to delay each printk during boot.
361 Values larger than 10 seconds (10000) are changed to
365 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
366 bttv.radio= Most important insmod options are available as
368 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
369 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
372 See drivers/scsi/BusLogic.c, comment before function
373 BusLogic_ParseDriverOptions().
375 c101= [NET] Moxa C101 synchronous serial card
377 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
378 Sometimes CPU hardware bugs make them report the cache
379 size incorrectly. The kernel will attempt work arounds
380 to fix known problems, but for some CPUs it is not
381 possible to determine what the correct size should be.
382 This option provides an override for these situations.
384 security= [SECURITY] Choose a security module to enable at boot.
385 If this boot parameter is not specified, only the first
386 security module asking for security registration will be
387 loaded. An invalid security module name will be treated
388 as if no module has been chosen.
391 [SECURITY] Disable capabilities. This would normally
392 be used only if an alternative security model is to be
393 configured. Potentially dangerous and should only be
394 used if you are entirely sure of the consequences.
396 ccw_timeout_log [S390]
397 See Documentation/s390/CommonIO for details.
399 cgroup_disable= [KNL] Disable a particular controller
400 Format: {name of the controller(s) to disable}
401 {Currently supported controllers - "memory"}
403 checkreqprot [SELINUX] Set initial checkreqprot flag value.
404 Format: { "0" | "1" }
405 See security/selinux/Kconfig help text.
406 0 -- check protection applied by kernel (includes
407 any implied execute protection).
408 1 -- check protection requested by application.
409 Default value is set via a kernel config option.
410 Value can be changed at runtime via
411 /selinux/checkreqprot.
414 See Documentation/s390/CommonIO for details.
416 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
418 Forces specified clocksource (if available) to be used
419 when calculating gettimeofday(). If specified
420 clocksource is not available, it defaults to PIT.
421 Format: { pit | tsc | cyclone | pmtmr }
423 clocksource= [GENERIC_TIME] Override the default clocksource
425 Override the default clocksource and use the clocksource
426 with the name specified.
427 Some clocksource names to choose from, depending on
429 [all] jiffies (this is the base, fallback clocksource)
431 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
432 pxa_timer,timer3,32k_counter,timer0_1
434 [X86-32] pit,hpet,tsc,vmi-timer;
435 scx200_hrt on Geode; cyclone on IBM x440
443 clearcpuid=BITNUM [X86]
444 Disable CPUID feature X for the kernel. See
445 include/asm-x86/cpufeature.h for the valid bit numbers.
446 Note the Linux specific bits are not necessarily
447 stable over kernel options, but the vendor specific
449 Also note that user programs calling CPUID directly
450 or using the feature without checking anything
451 will still see it. This just prevents it from
452 being used by the kernel or shown in /proc/cpuinfo.
453 Also note the kernel might malfunction if you disable
456 code_bytes [IA32/X86_64] How many bytes of object code to print
463 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
464 over the 8254 in addition to over the IO-APIC. The
465 kernel tries to set a sensible default.
467 hpet= [X86-32,HPET] option to control HPET usage
468 Format: { enable (default) | disable | force }
469 disable: disable HPET and use PIT instead
470 force: allow force enabled of undocumented chips (ICH4,
473 com20020= [HW,NET] ARCnet - COM20020 chipset
475 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
477 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
481 ARCnet - COM90xx chipset (memory-mapped buffers)
482 Format: <io>[,<irq>[,<memstart>]]
484 condev= [HW,S390] console device
487 console= [KNL] Output console device and options.
489 tty<n> Use the virtual console device <n>.
493 Use the specified serial port. The options are of
494 the form "bbbbpnf", where "bbbb" is the baud rate,
495 "p" is parity ("n", "o", or "e"), "n" is number of
496 bits, and "f" is flow control ("r" for RTS or
497 omit it). Default is "9600n8".
499 See Documentation/serial-console.txt for more
501 Documentation/networking/netconsole.txt for an
504 uart[8250],io,<addr>[,options]
505 uart[8250],mmio,<addr>[,options]
506 Start an early, polled-mode console on the 8250/16550
507 UART at the specified I/O port or MMIO address,
508 switching to the matching ttyS device later. The
509 options are the same as for ttyS, above.
511 If the device connected to the port is not a TTY but a braille
512 device, prepend "brl," before the device type, for instance
514 For now, only VisioBraille is supported.
516 earlycon= [KNL] Output early console device and options.
517 uart[8250],io,<addr>[,options]
518 uart[8250],mmio,<addr>[,options]
519 Start an early, polled-mode console on the 8250/16550
520 UART at the specified I/O port or MMIO address.
521 The options are the same as for ttyS, above.
524 [HW] Never suspend the console
525 Disable suspending of consoles during suspend and
526 hibernate operations. Once disabled, debugging
527 messages can reach various consoles while the rest
528 of the system is being put to sleep (ie, while
529 debugging driver suspend/resume hooks). This may
530 not work reliably with all consoles, but is known
531 to work with serial and VGA consoles.
533 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
535 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
537 crashkernel=nn[KMG]@ss[KMG]
538 [KNL] Reserve a chunk of physical memory to
539 hold a kernel to switch to with kexec on panic.
541 crashkernel=range1:size1[,range2:size2,...][@offset]
542 [KNL] Same as above, but depends on the memory
543 in the running system. The syntax of range is
544 start-[end] where start and end are both
545 a memory unit (amount[KMG]). See also
546 Documentation/kdump/kdump.txt for a example.
549 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
554 cs89x0_media= [HW,NET]
555 Format: { rj45 | aui | bnc }
558 See header of drivers/s390/block/dasd_devmap.c.
560 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
561 (one device per port)
562 Format: <port#>,<type>
563 See also Documentation/input/joystick-parport.txt
565 debug [KNL] Enable kernel debugging (events log level).
568 [KNL] verbose self-tests
570 Print debugging info while doing the locking API
572 We default to 0 (no extra messages), setting it to
573 1 will print _a lot_ more information - normally
574 only useful to kernel developers.
576 debug_objects [KNL] Enable object debugging
578 debugpat [X86] Enable PAT debugging
580 decnet.addr= [HW,NET]
581 Format: <area>[,<node>]
582 See also Documentation/networking/decnet.txt.
585 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
586 Change the default blue palette of the console.
587 This is a 16-member array composed of values
591 Format: <green0>,<green1>,<green2>,...,<green15>
592 Change the default green palette of the console.
593 This is a 16-member array composed of values
597 Format: <red0>,<red1>,<red2>,...,<red15>
598 Change the default red palette of the console.
599 This is a 16-member array composed of values
605 Set system-wide default UTF-8 mode for all tty's.
606 Default is 1, i.e. UTF-8 mode is enabled for all
607 newly opened terminals.
610 Set number of hash buckets for dentry cache.
613 IO parameters + enable/disable command.
615 digiepca= [HW,SERIAL]
616 See drivers/char/README.epca and
617 Documentation/digiepca.txt.
619 disable_mtrr_cleanup [X86]
620 enable_mtrr_cleanup [X86]
621 The kernel tries to adjust MTRR layout from continuous
622 to discrete, to make X server driver able to add WB
623 entry later. This parameter enables/disables that.
625 mtrr_chunk_size=nn[KMG] [X86]
626 used for mtrr cleanup. It is largest continous chunk
627 that could hold holes aka. UC entries.
629 mtrr_gran_size=nn[KMG] [X86]
630 Used for mtrr cleanup. It is granularity of mtrr block.
632 Large value could prevent small alignment from
635 mtrr_spare_reg_nr=n [X86]
637 Range: 0,7 : spare reg number
639 Used for mtrr cleanup. It is spare mtrr entries number.
640 Set to 2 or more if your graphical card needs more.
642 disable_mtrr_trim [X86, Intel and AMD only]
643 By default the kernel will trim any uncacheable
644 memory out of your available memory pool based on
645 MTRR settings. This parameter disables that behavior,
646 possibly causing your machine to run very slowly.
648 dmasound= [HW,OSS] Sound subsystem buffers
654 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
656 earlyprintk=serial[,ttySn[,baudrate]]
658 Append ",keep" to not disable it when the real console
661 Only vga or serial at a time, not both.
663 Currently only ttyS0 and ttyS1 are supported.
665 Interaction with the standard serial driver is not
668 The VGA output is eventually overwritten by the real
674 Format: {"off" | "on" | "skip[mbr]"}
676 eisa_irq_edge= [PARISC,HW]
677 See header of drivers/parisc/eisa.c.
680 See comment before function elanfreq_setup() in
681 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
684 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
685 See Documentation/block/as-iosched.txt and
686 Documentation/block/deadline-iosched.txt for details.
688 elfcorehdr= [X86-32, X86_64]
689 Specifies physical address of start of kernel core
690 image elf header. Generally kexec loader will
691 pass this option to capture kernel.
692 See Documentation/kdump/kdump.txt for details.
694 enforcing [SELINUX] Set initial enforcing status.
696 See security/selinux/Kconfig help text.
697 0 -- permissive (log only, no denials).
698 1 -- enforcing (deny and log).
700 Value can be changed at runtime via /selinux/enforce.
703 Format: <spdif>,[<nomix>,[<amplifier>]]
704 See also header of sound/oss/es1371.c.
706 ether= [HW,NET] Ethernet cards parameters
707 This option is obsoleted by the "netdev=" option, which
708 has equivalent usage. See its documentation for details.
710 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
715 fail_make_request=[KNL]
716 General fault injection mechanism.
717 Format: <interval>,<probability>,<space>,<times>
718 See also /Documentation/fault-injection/.
721 See header of drivers/scsi/fd_mcs.c.
724 See header of drivers/scsi/fdomain.c.
727 See Documentation/floppy.txt.
729 force_pal_cache_flush
730 [IA-64] Avoid check_sal_cache_flush which may hang on
731 buggy SAL_CACHE_FLUSH implementations. Using this
732 parameter will force ia64_sal_cache_flush to call
733 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
736 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
737 support via parallel port (up to 5 devices per port)
738 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
739 See also Documentation/input/joystick-parport.txt
743 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
748 See header of drivers/scsi/gdth.c.
750 gpt [EFI] Forces disk with valid GPT signature but
751 invalid Protective MBR to be treated as GPT.
755 hashdist= [KNL,NUMA] Large hashes allocated during boot
756 are distributed across NUMA nodes. Defaults on
757 for IA-64, off otherwise.
758 Format: 0 | 1 (for off | on)
760 hcl= [IA-64] SGI's Hardware Graph compatibility layer
762 hd= [EIDE] (E)IDE hard drive subsystem geometry
763 Format: <cyl>,<head>,<sect>
765 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
766 size of <nn>. This works even on boxes that have no
767 highmem otherwise. This also works to reduce highmem
768 size on bigger boxes.
770 highres= [KNL] Enable/disable high resolution timer mode.
771 Valid parameters: "on", "off"
775 See Documentation/isdn/README.HiSax.
777 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
778 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
779 On x86 this option can be specified multiple times
780 interleaved with hugepages= to reserve huge pages
781 of different sizes. Valid pages sizes on x86-64
782 are 2M (when the CPU supports "pse") and 1G (when the
783 CPU supports the "pdpe1gb" cpuinfo flag)
784 Note that 1GB pages can only be allocated at boot time
785 using hugepages= and not freed afterwards.
787 [same as hugepagesz=] The size of the default
788 HugeTLB page size. This is the size represented by
789 the legacy /proc/ hugepages APIs, used for SHM, and
790 default size when mounting hugetlbfs filesystems.
791 Defaults to the default architecture's huge page size
794 i8042.direct [HW] Put keyboard port into non-translated mode
795 i8042.dumbkbd [HW] Pretend that controller can only read data from
796 keyboard and cannot control its state
797 (Don't attempt to blink the leds)
798 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
799 i8042.nokbd [HW] Don't check/create keyboard port
800 i8042.noloop [HW] Disable the AUX Loopback command while probing
802 i8042.nomux [HW] Don't check presence of an active multiplexing
804 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
807 [HW] Frequency with which keyboard LEDs should blink
808 when kernel panics (default is 0.5 sec)
809 i8042.reset [HW] Reset the controller during init and cleanup
810 i8042.unlock [HW] Unlock (ignore) the keylock
814 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
815 indicates that the driver is running on unsupported
817 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
818 does not match list of supported models.
820 [HW] Report power status in /proc/i8k
821 (disabled by default)
822 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
825 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
826 See Documentation/mca.txt.
829 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
831 ide= [HW] (E)IDE subsystem
832 Format: ide=nodma or ide=doubler
833 See Documentation/ide/ide.txt.
835 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
836 See Documentation/ide/ide.txt.
839 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
840 Poll forces a polling idle loop that can slightly improves the performance
841 of waking up a idle CPU, but will use a lot of power and make the system
842 run hot. Not recommended.
843 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
844 to not use it because it doesn't save as much power as a normal idle
845 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
847 idle=halt. Halt is forced to be used for CPU idle.
848 In such case C2/C3 won't be used again.
849 idle=nomwait. Disable mwait for CPU C-states
851 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
852 Claim all unknown PCI IDE storage controllers.
854 ignore_loglevel [KNL]
855 Ignore loglevel setting - this will print /all/
856 kernel messages to the console. Useful for debugging.
859 Set number of hash buckets for inode cache.
862 See header of drivers/scsi/in2000.c.
866 Run specified binary instead of /sbin/init as init
869 initcall_debug [KNL] Trace initcalls as they are executed. Useful
870 for working out where the kernel is dying during
873 initrd= [BOOT] Specify the location of the initial ramdisk
875 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
893 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
895 Disable intel iommu driver.
896 igfx_off [Default Off]
897 By default, gfx is mapped as normal device. If a gfx
898 device has a dedicated DMAR unit, the DMAR unit is
899 bypassed by not enabling DMAR with this option. In
900 this case, gfx device will use physical address for
903 With this option iommu will not optimize to look
904 for io virtual address below 32 bit forcing dual
905 address cycle on pci bus for cards supporting greater
906 than 32 bit addressing. The default is to look
907 for translation below 32 bit and if not available
908 then look in the higher range.
910 With this option on every unmap_single operation will
911 result in a hardware IOTLB flush operation as opposed
912 to batching them for performance.
914 io_delay= [X86-32,X86-64] I/O delay method
916 Standard port 0x80 based delay
918 Alternate port 0xed based delay (needed on some systems)
920 Simple two microseconds delay
924 io7= [HW] IO7 for Marvel based alpha systems
925 See comment before marvel_specify_io7 in
926 arch/alpha/kernel/core_marvel.c.
929 See Documentation/filesystems/nfsroot.txt.
931 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
932 See comment before ip2_setup() in
933 drivers/char/ip2/ip2base.c.
935 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
936 See header of drivers/scsi/ips.c.
938 ports= [IP_VS_FTP] IPVS ftp helper module
940 Up to 8 (IP_VS_APP_MAX_PORTS) ports
942 Format: <port>,<port>....
945 When an interrupt is not handled search all handlers
946 for it. Intended to get systems with badly broken
950 When an interrupt is not handled search all handlers
951 for it. Also check all handlers each timer
952 interrupt. Intended to get systems with badly broken
956 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
958 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
960 <cpu number>,...,<cpu number>
962 <cpu number>-<cpu number> (must be a positive range in ascending order)
964 <cpu number>,...,<cpu number>-<cpu number>
965 This option can be used to specify one or more CPUs
966 to isolate from the general SMP balancing and scheduling
967 algorithms. The only way to move a process onto or off
968 an "isolated" CPU is via the CPU affinity syscalls.
969 <cpu number> begins at 0 and the maximum value is
970 "number of CPUs in system - 1".
972 This option is the preferred way to isolate CPUs. The
973 alternative -- manually setting the CPU mask of all
974 tasks in the system -- can cause problems and
975 suboptimal load balancer performance.
979 js= [HW,JOY] Analog joystick
980 See Documentation/input/joystick.txt.
982 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
983 specifies the amount of memory usable by the kernel
984 for non-movable allocations. The requested amount is
985 spread evenly throughout all nodes in the system. The
986 remaining memory in each node is used for Movable
987 pages. In the event, a node is too small to have both
988 kernelcore and Movable pages, kernelcore pages will
989 take priority and other nodes will have a larger number
990 of kernelcore pages. The Movable zone is used for the
991 allocation of pages that may be reclaimed or moved
992 by the page migration subsystem. This means that
993 HugeTLB pages may not be allocated from this zone.
994 Note that allocations like PTEs-from-HighMem still
995 use the HighMem zone if it exists, and the Normal
998 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
999 is similar to kernelcore except it specifies the
1000 amount of memory used for migratable allocations.
1001 If both kernelcore and movablecore is specified,
1002 then kernelcore will be at *least* the specified
1003 value but may be more. If movablecore on its own
1004 is specified, the administrator must be careful
1005 that the amount of memory usable for all allocations
1010 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1013 kgdboc= [HW] kgdb over consoles.
1014 Requires a tty driver that supports console polling.
1015 (only serial suported for now)
1016 Format: <serial_device>[,baud]
1022 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1025 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1028 libata.dma= [LIBATA] DMA control
1029 libata.dma=0 Disable all PATA and SATA DMA
1030 libata.dma=1 PATA and SATA Disk DMA only
1031 libata.dma=2 ATAPI (CDROM) DMA only
1032 libata.dma=4 Compact Flash DMA only
1033 Combinations also work, so libata.dma=3 enables DMA
1034 for disks and CDROMs, but not CFs.
1036 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1040 libata.force= [LIBATA] Force configurations. The format is comma
1041 separated list of "[ID:]VAL" where ID is
1042 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1043 matching port, link or device. Basically, it matches
1044 the ATA ID string printed on console by libata. If
1045 the whole ID part is omitted, the last PORT and DEVICE
1046 values are used. If ID hasn't been specified yet, the
1047 configuration applies to all ports, links and devices.
1049 If only DEVICE is omitted, the parameter applies to
1050 the port and all links and devices behind it. DEVICE
1051 number of 0 either selects the first device or the
1052 first fan-out link behind PMP device. It does not
1053 select the host link. DEVICE number of 15 selects the
1054 host link and device attached to it.
1056 The VAL specifies the configuration to force. As long
1057 as there's no ambiguity shortcut notation is allowed.
1058 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1059 The following configurations can be forced.
1061 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1062 Any ID with matching PORT is used.
1064 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1066 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1067 udma[/][16,25,33,44,66,100,133] notation is also
1070 * [no]ncq: Turn on or off NCQ.
1072 If there are multiple matching configurations changing
1073 the same attribute, the last one is used.
1075 load_ramdisk= [RAM] List of ramdisks to load from floppy
1076 See Documentation/ramdisk.txt.
1078 lockd.nlm_grace_period=P [NFS] Assign grace period.
1081 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1084 lockd.nlm_timeout=T [NFS] Assign timeout value.
1087 lockd.nlm_udpport=M [NFS] Assign UDP port.
1090 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1093 loglevel= All Kernel Messages with a loglevel smaller than the
1094 console loglevel will be printed to the console. It can
1095 also be changed with klogd or other programs. The
1096 loglevels are defined as follows:
1098 0 (KERN_EMERG) system is unusable
1099 1 (KERN_ALERT) action must be taken immediately
1100 2 (KERN_CRIT) critical conditions
1101 3 (KERN_ERR) error conditions
1102 4 (KERN_WARNING) warning conditions
1103 5 (KERN_NOTICE) normal but significant condition
1104 6 (KERN_INFO) informational
1105 7 (KERN_DEBUG) debug-level messages
1107 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1108 Format: { n | nk | nM }
1109 n must be a power of two. The default size
1110 is set in the kernel config file.
1112 logo.nologo [FB] Disables display of the built-in Linux logo.
1113 This may be used to provide more screen space for
1114 kernel log messages and is useful when debugging
1115 kernel boot problems.
1117 lp=0 [LP] Specify parallel ports to use, e.g,
1118 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1119 lp=reset first parallel port). 'lp=0' disables the
1120 lp=auto printer driver. 'lp=reset' (which can be
1121 specified in addition to the ports) causes
1122 attached printers to be reset. Using
1123 lp=port1,port2,... specifies the parallel ports
1124 to associate lp devices with, starting with
1125 lp0. A port specification may be 'none' to skip
1126 that lp device, or a parport name such as
1127 'parport0'. Specifying 'lp=auto' instead of a
1128 port specification list means that device IDs
1129 from each port should be examined, to see if
1130 an IEEE 1284-compliant printer is attached; if
1131 so, the driver will manage that printer.
1132 See also header of drivers/char/lp.c.
1135 Sets loops_per_jiffy to given constant, thus avoiding
1136 time-consuming boot-time autodetection (up to 250 ms per
1137 CPU). 0 enables autodetection (default). To determine
1138 the correct value for your kernel, boot with normal
1139 autodetection and see what value is printed. Note that
1140 on SMP systems the preset will be applied to all CPUs,
1141 which is likely to cause problems if your CPUs need
1142 significantly divergent settings. An incorrect value
1143 will cause delays in the kernel to be wrong, leading to
1144 unpredictable I/O errors and other breakage. Although
1145 unlikely, in the extreme case this might damage your
1149 Format: <io>,<irq>,<dma>
1151 mac5380= [HW,SCSI] Format:
1152 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1154 machvec= [IA64] Force the use of a particular machine-vector
1155 (machvec) in a generic kernel.
1156 Example: machvec=hpzx1_swiotlb
1158 max_loop= [LOOP] Maximum number of loopback devices that can
1162 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1163 should make use of. maxcpus=n : n >= 0 limits the
1164 kernel to using 'n' processors. n=0 is a special case,
1165 it is equivalent to "nosmp", which also disables
1168 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1169 equal to this physical address is ignored.
1171 max_luns= [SCSI] Maximum number of LUNs to probe.
1172 Should be between 1 and 2^32-1.
1175 [SCSI] Maximum number of LUNs received.
1176 Should be between 1 and 16384.
1180 mce [X86-32] Machine Check Exception
1182 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1184 md= [HW] RAID subsystems devices and level
1185 See Documentation/md.txt.
1188 Format: <first>,<last>
1189 Specifies range of consoles to be captured by the MDA.
1191 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1192 Amount of memory to be used when the kernel is not able
1193 to see the whole system memory or for test.
1194 [X86-32] Use together with memmap= to avoid physical
1195 address space collisions. Without memmap= PCI devices
1196 could be placed at addresses belonging to unused RAM.
1198 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1201 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1202 E820 memory map, as specified by the user.
1203 Such memmap=exactmap lines can be constructed based on
1204 BIOS output or other requirements. See the memmap=nn@ss
1207 memmap=nn[KMG]@ss[KMG]
1208 [KNL] Force usage of a specific region of memory
1209 Region of memory to be used, from ss to ss+nn.
1211 memmap=nn[KMG]#ss[KMG]
1212 [KNL,ACPI] Mark specific memory as ACPI data.
1213 Region of memory to be used, from ss to ss+nn.
1215 memmap=nn[KMG]$ss[KMG]
1216 [KNL,ACPI] Mark specific memory as reserved.
1217 Region of memory to be used, from ss to ss+nn.
1218 Example: Exclude memory from 0x18690000-0x1869ffff
1219 memmap=64K$0x18690000
1221 memmap=0x10000$0x18690000
1223 memtest= [KNL,X86] Enable memtest
1225 range: 0,4 : pattern number
1226 default : 0 <disable>
1228 meye.*= [HW] Set MotionEye Camera parameters
1229 See Documentation/video4linux/meye.txt.
1231 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1232 Multi-Function General Purpose Timers on AMD Geode
1235 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1236 the BIOS has incorrectly applied a workaround. TinyBIOS
1237 version 0.98 is known to be affected, 0.99 fixes the
1238 problem by letting the user disable the workaround.
1243 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1244 parameter allows control of the logging verbosity for
1245 the additional memory initialisation checks. A value
1246 of 0 disables mminit logging and a level of 4 will
1247 log everything. Information is printed at KERN_DEBUG
1248 so loglevel=8 may also need to be specified.
1251 [MOUSE] Maximum time between finger touching and
1252 leaving touchpad surface for touch to be considered
1253 a tap and be reported as a left button click (for
1254 touchpads working in absolute mode only).
1256 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1257 reporting absolute coordinates, such as tablets
1258 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1259 reporting absolute coordinates, such as tablets
1264 MTD_Partition= [MTD]
1265 Format: <name>,<region-number>,<size>,<offset>
1267 MTD_Region= [MTD] Format:
1268 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1271 See drivers/mtd/cmdlinepart.c.
1274 ARM/S3C2412 JIVE boot control
1276 See arch/arm/mach-s3c2412/mach-jive.c
1278 mtouchusb.raw_coordinates=
1279 [HW] Make the MicroTouch USB driver use raw coordinates
1280 ('y', default) or cooked coordinates ('n')
1282 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1285 See header of drivers/scsi/NCR_D700.c.
1289 ncr53c400= [HW,SCSI]
1291 ncr53c400a= [HW,SCSI]
1293 ncr53c406a= [HW,SCSI]
1295 ncr53c8xx= [HW,SCSI]
1297 netdev= [NET] Network devices parameters
1298 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1299 Note that mem_start is often overloaded to mean
1300 something different and driver-specific.
1301 This usage is only documented in each driver source
1305 [NETFILTER] Enable connection tracking flow accounting
1306 0 to disable accounting
1307 1 to enable accounting
1308 Default value depends on CONFIG_NF_CT_ACCT that is
1309 going to be removed in 2.6.29.
1312 See Documentation/filesystems/nfsroot.txt.
1314 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1315 See Documentation/filesystems/nfsroot.txt.
1317 nfs.callback_tcpport=
1318 [NFS] set the TCP port on which the NFSv4 callback
1319 channel should listen.
1321 nfs.idmap_cache_timeout=
1322 [NFS] set the maximum lifetime for idmapper cache
1326 [NFS] enable 64-bit inode numbers.
1327 If zero, the NFS client will fake up a 32-bit inode
1328 number for the readdir() and stat() syscalls instead
1329 of returning the full 64-bit number.
1330 The default is to return 64-bit inode numbers.
1332 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1333 when a NMI is triggered.
1334 Format: [state][,regs][,debounce][,die]
1336 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1338 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1339 emulation library even if a 387 maths coprocessor
1342 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1343 caches in the slab allocator. Saves per-node memory,
1344 but will impact performance.
1348 noapic [SMP,APIC] Tells the kernel to not make use of any
1349 IOAPICs that may be present in the system.
1351 nobats [PPC] Do not use BATs for mapping kernel lowmem
1352 on "Classic" PPC cores.
1356 nodelayacct [KNL] Disable per-task delay accounting
1358 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1360 noefi [X86-32,X86-64] Disable EFI runtime services support.
1364 noexec [X86-32,X86-64]
1365 On X86-32 available only on PAE configured kernels.
1366 noexec=on: enable non-executable mappings (default)
1367 noexec=off: disable non-executable mappings
1370 This affects only 32-bit executables.
1371 noexec32=on: enable non-executable mappings (default)
1372 read doesn't imply executable mappings
1373 noexec32=off: disable non-executable mappings
1374 read implies executable mappings
1376 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1377 register save and restore. The kernel will only save
1378 legacy floating-point registers on task switch.
1380 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1384 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1385 instruction doesn't work correctly and not to
1388 nohalt [IA-64] Tells the kernel not to use the power saving
1389 function PAL_HALT_LIGHT when idle. This increases
1390 power-consumption. On the positive side, it reduces
1391 interrupt wake-up latency, which may improve performance
1392 in certain environments such as networked servers or
1395 nohz= [KNL] Boottime enable/disable dynamic ticks
1396 Valid arguments: on, off
1399 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1401 noirqdebug [X86-32] Disables the code which attempts to detect and
1402 disable unhandled interrupt sources.
1404 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1405 broken timer IRQ sources.
1407 noisapnp [ISAPNP] Disables ISA PnP code.
1409 noinitrd [RAM] Tells the kernel not to load any configured
1414 nojitter [IA64] Disables jitter checking for ITC timers.
1416 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1418 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1420 noltlbs [PPC] Do not use large page/tlb entries for kernel
1421 lowmem mapping on PPC40x.
1423 nomca [IA-64] Disable machine check abort handling
1425 nomce [X86-32] Machine Check Exception
1427 nomfgpt [X86-32] Disable Multi-Function General Purpose
1428 Timer usage (for AMD Geode machines).
1430 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1432 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1433 with UP alternatives
1435 noresidual [PPC] Don't use residual data on PReP machines.
1437 noresume [SWSUSP] Disables resume and restores original swap
1440 no-scroll [VGA] Disables scrollback.
1441 This is required for the Braillex ib80-piezo Braille
1442 reader made by F.H. Papenmeier (Germany).
1446 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1448 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1449 and disable the IO APIC. legacy for "maxcpus=0".
1451 nosoftlockup [KNL] Disable the soft-lockup detector.
1453 nosync [HW,M68K] Disables sync negotiation for all devices.
1455 notsc [BUGS=X86-32] Disable Time Stamp Counter
1457 nousb [USB] Disable the USB subsystem
1461 nptcg= [IA64] Override max number of concurrent global TLB
1462 purges which is reported from either PAL_VM_SUMMARY or
1465 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1466 one of ['zone', 'node', 'default'] can be specified
1467 This can be set from sysctl after boot.
1468 See Documentation/sysctl/vm.txt for details.
1470 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1472 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1473 Rather than timing out after 20 ms if an EC
1474 command is not properly ACKed, override the length
1475 of the timeout. We have interrupts disabled while
1476 waiting for the ACK, so if this is set too high
1477 interrupts *may* be lost!
1482 oprofile.timer= [HW]
1483 Use timer interrupt instead of performance counters
1485 osst= [HW,SCSI] SCSI Tape Driver
1486 Format: <buffer_size>,<write_threshold>
1487 See also Documentation/scsi/st.txt.
1489 panic= [KNL] Kernel behaviour on panic
1492 parkbd.port= [HW] Parallel port number the keyboard adapter is
1493 connected to, default is 0.
1495 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1496 0 for XT, 1 for AT (default is AT).
1499 parport= [HW,PPT] Specify parallel ports. 0 disables.
1500 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1501 Use 'auto' to force the driver to use any
1502 IRQ/DMA settings detected (the default is to
1503 ignore detected IRQ/DMA settings because of
1504 possible conflicts). You can specify the base
1505 address, IRQ, and DMA settings; IRQ and DMA
1506 should be numbers, or 'auto' (for using detected
1507 settings on that particular port), or 'nofifo'
1508 (to avoid using a FIFO even if it is detected).
1509 Parallel ports are assigned in the order they
1510 are specified on the command line, starting
1513 parport_init_mode= [HW,PPT]
1514 Configure VIA parallel port to operate in
1515 a specific mode. This is necessary on Pegasos
1516 computer where firmware has no options for setting
1517 up parallel port mode and sets it to spp.
1518 Currently this function knows 686a and 8231 chips.
1519 Format: [spp|ps2|epp|ecp|ecpepp]
1521 pas2= [HW,OSS] Format:
1522 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1525 See header of drivers/scsi/pas16.c.
1528 Halt all CPUs after the first oops has been printed for
1529 the specified number of seconds. This is to be used if
1530 your oopses keep scrolling off the screen.
1535 See header of drivers/block/paride/pcd.c.
1536 See also Documentation/paride.txt.
1538 pci=option[,option...] [PCI] various PCI subsystem options:
1539 off [X86-32] don't probe for the PCI bus
1540 bios [X86-32] force use of PCI BIOS, don't access
1541 the hardware directly. Use this if your machine
1542 has a non-standard PCI host bridge.
1543 nobios [X86-32] disallow use of PCI BIOS, only direct
1544 hardware access methods are allowed. Use this
1545 if you experience crashes upon bootup and you
1546 suspect they are caused by the BIOS.
1547 conf1 [X86-32] Force use of PCI Configuration
1549 conf2 [X86-32] Force use of PCI Configuration
1551 noaer [PCIE] If the PCIEAER kernel config parameter is
1552 enabled, this kernel boot option can be used to
1553 disable the use of PCIE advanced error reporting.
1554 nodomains [PCI] Disable support for multiple PCI
1555 root domains (aka PCI segments, in ACPI-speak).
1556 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1558 nomsi [MSI] If the PCI_MSI kernel config parameter is
1559 enabled, this kernel boot option can be used to
1560 disable the use of MSI interrupts system-wide.
1561 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1562 routing table. These calls are known to be buggy
1563 on several machines and they hang the machine
1564 when used, but on other computers it's the only
1565 way to get the interrupt routing table. Try
1566 this option if the kernel is unable to allocate
1567 IRQs or discover secondary PCI buses on your
1569 rom [X86-32] Assign address space to expansion ROMs.
1570 Use with caution as certain devices share
1571 address decoders between ROMs and other
1573 norom [X86-32,X86_64] Do not assign address space to
1574 expansion ROMs that do not already have
1575 BIOS assigned address ranges.
1576 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1577 assigned automatically to PCI devices. You can
1578 make the kernel exclude IRQs of your ISA cards
1580 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1581 of the PIRQ table (normally generated
1582 by the BIOS) if it is outside the
1583 F0000h-100000h range.
1584 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1585 useful if the kernel is unable to find your
1586 secondary buses and you want to tell it
1587 explicitly which ones they are.
1588 assign-busses [X86-32] Always assign all PCI bus
1589 numbers ourselves, overriding
1590 whatever the firmware may have done.
1591 usepirqmask [X86-32] Honor the possible IRQ mask stored
1592 in the BIOS $PIR table. This is needed on
1593 some systems with broken BIOSes, notably
1594 some HP Pavilion N5400 and Omnibook XE3
1595 notebooks. This will have no effect if ACPI
1596 IRQ routing is enabled.
1597 noacpi [X86-32] Do not use ACPI for IRQ routing
1598 or for PCI scanning.
1599 use_crs [X86-32] Use _CRS for PCI resource
1601 routeirq Do IRQ routing for all PCI devices.
1602 This is normally done in pci_enable_device(),
1603 so this option is a temporary workaround
1604 for broken drivers that don't call it.
1605 skip_isa_align [X86] do not align io start addr, so can
1606 handle more pci cards
1607 firmware [ARM] Do not re-enumerate the bus but instead
1608 just use the configuration from the
1609 bootloader. This is currently used on
1610 IXP2000 systems where the bus has to be
1611 configured a certain way for adjunct CPUs.
1612 noearly [X86] Don't do any early type 1 scanning.
1613 This might help on some broken boards which
1614 machine check when some devices' config space
1615 is read. But various workarounds are disabled
1616 and some IOMMU drivers will not work.
1617 bfsort Sort PCI devices into breadth-first order.
1618 This sorting is done to get a device
1619 order compatible with older (<= 2.4) kernels.
1620 nobfsort Don't sort PCI devices into breadth-first order.
1621 cbiosize=nn[KMG] The fixed amount of bus space which is
1622 reserved for the CardBus bridge's IO window.
1623 The default value is 256 bytes.
1624 cbmemsize=nn[KMG] The fixed amount of bus space which is
1625 reserved for the CardBus bridge's memory
1626 window. The default value is 64 megabytes.
1628 pcmv= [HW,PCMCIA] BadgePAD 4
1631 See Documentation/paride.txt.
1633 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1636 See arch/parisc/kernel/pdc_chassis.c
1639 See Documentation/paride.txt.
1642 See Documentation/paride.txt.
1644 pirq= [SMP,APIC] Manual mp-table setup
1645 See Documentation/i386/IO-APIC.txt.
1647 plip= [PPT,NET] Parallel port network link
1648 Format: { parport<nr> | timid | 0 }
1649 See also Documentation/parport.txt.
1651 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1652 Override pmtimer IOPort with a hex value.
1659 { on | off | curr | res | no-curr | no-res }
1662 [ISAPNP] Exclude IRQs for the autoconfiguration
1665 [ISAPNP] Exclude DMAs for the autoconfiguration
1667 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1668 Ranges are in pairs (I/O port base and size).
1671 [ISAPNP] Exclude memory regions for the
1673 Ranges are in pairs (memory base and size).
1675 print-fatal-signals=
1676 [KNL] debug: print fatal signals
1677 print-fatal-signals=1: print segfault info to
1681 printk.time= Show timing data prefixed to each printk message line
1682 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1684 profile= [KNL] Enable kernel profiling via /proc/profile
1685 Format: [schedule,]<number>
1686 Param: "schedule" - profile schedule points.
1687 Param: <number> - step/bucket size as a power of 2 for
1688 statistical time based profiling.
1689 Param: "sleep" - profile D-state sleeping (millisecs).
1690 Requires CONFIG_SCHEDSTATS
1691 Param: "kvm" - profile VM exits.
1693 processor.max_cstate= [HW,ACPI]
1694 Limit processor to maximum C-state
1695 max_cstate=9 overrides any DMI blacklist limit.
1697 processor.nocst [HW,ACPI]
1698 Ignore the _CST method to determine C-states,
1699 instead using the legacy FADT method
1701 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1703 See Documentation/ramdisk.txt.
1705 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1706 probe for; one of (bare|imps|exps|lifebook|any).
1707 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1709 psmouse.resetafter= [HW,MOUSE]
1710 Try to reset the device after so many bad packets
1713 [HW,MOUSE] Set desired mouse resolution, in dpi.
1714 psmouse.smartscroll=
1715 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1716 0 = disabled, 1 = enabled (default).
1718 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1720 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1723 See Documentation/paride.txt.
1726 [KNL] Number of legacy pty's. Overwrites compiled-in
1729 quiet [KNL] Disable most log messages
1734 See Documentation/md.txt.
1736 ramdisk_blocksize= [RAM]
1737 See Documentation/ramdisk.txt.
1739 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1740 See Documentation/ramdisk.txt.
1742 rcupdate.blimit= [KNL,BOOT]
1743 Set maximum number of finished RCU callbacks to process
1746 rcupdate.qhimark= [KNL,BOOT]
1747 Set threshold of queued
1748 RCU callbacks over which batch limiting is disabled.
1750 rcupdate.qlowmark= [KNL,BOOT]
1751 Set threshold of queued RCU callbacks below which
1752 batch limiting is re-enabled.
1756 Run specified binary instead of /init from the ramdisk,
1757 used for early userspace startup. See initrd.
1759 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1760 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1761 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1764 [KNL, SMP] Set scheduler's default relax_domain_level.
1765 See Documentation/cpusets.txt.
1767 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1769 reservetop= [X86-32]
1771 Reserves a hole at the top of the kernel virtual
1774 reset_devices [KNL] Force drivers to reset the underlying device
1775 during initialization.
1778 Specify the partition device for software suspend
1780 resume_offset= [SWSUSP]
1781 Specify the offset from the beginning of the partition
1782 given by "resume=" at which the swap header is located,
1783 in <PAGE_SIZE> units (needed only for swap files).
1784 See Documentation/power/swsusp-and-swap-files.txt
1786 retain_initrd [RAM] Keep initrd memory after extraction
1788 rhash_entries= [KNL,NET]
1789 Set number of hash buckets for route cache
1791 riscom8= [HW,SERIAL]
1792 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1794 ro [KNL] Mount root device read-only on boot
1796 root= [KNL] Root filesystem
1798 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1799 mount the root filesystem
1801 rootflags= [KNL] Set root filesystem mount option string
1803 rootfstype= [KNL] Set root filesystem type
1805 rootwait [KNL] Wait (indefinitely) for root device to show up.
1806 Useful for devices that are detected asynchronously
1807 (e.g. USB and MMC devices).
1809 root_plug.vendor_id=
1810 [ROOTPLUG] Override the default vendor ID
1812 root_plug.product_id=
1813 [ROOTPLUG] Override the default product ID
1816 [ROOTPLUG] Enable debugging output
1818 rw [KNL] Mount root device read-write on boot
1820 S [KNL] Run init in single mode
1823 See drivers/net/irda/sa1100_ir.c.
1825 sbni= [NET] Granch SBNI12 leased line adapter
1827 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1828 Format: <io>[,<timeout>[,<isapnp>]]
1830 scsi_debug_*= [SCSI]
1831 See drivers/scsi/scsi_debug.c.
1833 scsi_default_dev_flags=
1834 [SCSI] SCSI default device flags
1837 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1838 Format: <vendor>:<model>:<flags>
1839 (flags are integer value)
1841 scsi_logging_level= [SCSI] a bit mask of logging levels
1842 See drivers/scsi/scsi_logging.h for bits. Also
1843 settable via sysctl at dev.scsi.logging_level
1844 (/proc/sys/dev/scsi/logging_level).
1845 There is also a nice 'scsi_logging_level' script in the
1846 S390-tools package, available for download at
1847 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1849 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1850 discovered. async scans them in kernel threads,
1851 allowing boot to proceed. none ignores them, expecting
1852 user space to do the scan.
1854 selinux [SELINUX] Disable or enable SELinux at boot time.
1855 Format: { "0" | "1" }
1856 See security/selinux/Kconfig help text.
1859 Default value is set via kernel config option.
1860 If enabled at boot time, /selinux/disable can be used
1861 later to disable prior to initial policy load.
1863 selinux_compat_net =
1864 [SELINUX] Set initial selinux_compat_net flag value.
1865 Format: { "0" | "1" }
1866 0 -- use new secmark-based packet controls
1867 1 -- use legacy packet controls
1868 Default value is 0 (preferred).
1869 Value can be changed at runtime via
1870 /selinux/compat_net.
1872 serialnumber [BUGS=X86-32]
1875 Maximal number of shapers.
1878 See header of drivers/scsi/sim710.c.
1885 slub_debug[=options[,slabs]] [MM, SLUB]
1886 Enabling slub_debug allows one to determine the
1887 culprit if slab objects become corrupted. Enabling
1888 slub_debug can create guard zones around objects and
1889 may poison objects when not in use. Also tracks the
1890 last alloc / free. For more information see
1891 Documentation/vm/slub.txt.
1893 slub_max_order= [MM, SLUB]
1894 Determines the maximum allowed order for slabs.
1895 A high setting may cause OOMs due to memory
1896 fragmentation. For more information see
1897 Documentation/vm/slub.txt.
1899 slub_min_objects= [MM, SLUB]
1900 The minimum number of objects per slab. SLUB will
1901 increase the slab order up to slub_max_order to
1902 generate a sufficiently large slab able to contain
1903 the number of objects indicated. The higher the number
1904 of objects the smaller the overhead of tracking slabs
1905 and the less frequently locks need to be acquired.
1906 For more information see Documentation/vm/slub.txt.
1908 slub_min_order= [MM, SLUB]
1909 Determines the mininum page order for slabs. Must be
1910 lower than slub_max_order.
1911 For more information see Documentation/vm/slub.txt.
1913 slub_nomerge [MM, SLUB]
1914 Disable merging of slabs with similar size. May be
1915 necessary if there is some reason to distinguish
1916 allocs to different slabs. Debug options disable
1917 merging on their own.
1918 For more information see Documentation/vm/slub.txt.
1921 Format: <io1>[,<io2>[,...,<io8>]]
1923 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1924 attempt to substitute SMP alternatives once at boot.
1926 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1927 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1928 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1929 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1930 smsc-ircc2.ircc_irq= [HW] IRQ line
1931 smsc-ircc2.ircc_dma= [HW] DMA channel
1932 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1933 0: Toshiba Satellite 1800 (GP data pin select)
1934 1: Fast pin select (default)
1937 snd-ad1816a= [HW,ALSA]
1939 snd-ad1848= [HW,ALSA]
1941 snd-ali5451= [HW,ALSA]
1943 snd-als100= [HW,ALSA]
1945 snd-als4000= [HW,ALSA]
1947 snd-azt2320= [HW,ALSA]
1949 snd-cmi8330= [HW,ALSA]
1951 snd-cmipci= [HW,ALSA]
1953 snd-cs4231= [HW,ALSA]
1955 snd-cs4232= [HW,ALSA]
1957 snd-cs4236= [HW,ALSA]
1959 snd-cs4281= [HW,ALSA]
1961 snd-cs46xx= [HW,ALSA]
1963 snd-dt019x= [HW,ALSA]
1965 snd-dummy= [HW,ALSA]
1967 snd-emu10k1= [HW,ALSA]
1969 snd-ens1370= [HW,ALSA]
1971 snd-ens1371= [HW,ALSA]
1973 snd-es968= [HW,ALSA]
1975 snd-es1688= [HW,ALSA]
1977 snd-es18xx= [HW,ALSA]
1979 snd-es1938= [HW,ALSA]
1981 snd-es1968= [HW,ALSA]
1983 snd-fm801= [HW,ALSA]
1985 snd-gusclassic= [HW,ALSA]
1987 snd-gusextreme= [HW,ALSA]
1989 snd-gusmax= [HW,ALSA]
1993 snd-ice1712= [HW,ALSA]
1995 snd-intel8x0= [HW,ALSA]
1997 snd-interwave= [HW,ALSA]
2002 snd-korg1212= [HW,ALSA]
2004 snd-maestro3= [HW,ALSA]
2006 snd-mpu401= [HW,ALSA]
2008 snd-mtpav= [HW,ALSA]
2010 snd-nm256= [HW,ALSA]
2012 snd-opl3sa2= [HW,ALSA]
2020 snd-opti93x= [HW,ALSA]
2024 snd-rme32= [HW,ALSA]
2026 snd-rme96= [HW,ALSA]
2028 snd-rme9652= [HW,ALSA]
2034 snd-sbawe= [HW,ALSA]
2036 snd-serial= [HW,ALSA]
2038 snd-sgalaxy= [HW,ALSA]
2040 snd-sonicvibes= [HW,ALSA]
2045 snd-sun-cs4231= [HW,ALSA]
2047 snd-trident= [HW,ALSA]
2049 snd-usb-audio= [HW,ALSA,USB]
2051 snd-via82xx= [HW,ALSA]
2053 snd-virmidi= [HW,ALSA]
2055 snd-wavefront= [HW,ALSA]
2057 snd-ymfpci= [HW,ALSA]
2060 [KNL] Should the soft-lockup detector generate panics.
2062 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2063 See Documentation/sonypi.txt
2065 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2066 See Documentation/specialix.txt.
2068 spia_io_base= [HW,MTD]
2074 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2076 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2077 See Documentation/scsi/st.txt.
2081 Set the STI (builtin display/keyboard on the HP-PARISC
2082 machines) console (graphic card) which should be used
2083 as the initial boot-console.
2084 See also comment in drivers/video/console/sticore.c.
2087 See comment in drivers/video/console/sticore.c.
2090 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2094 Control how the NFS server code allocates CPUs to
2095 service thread pools. Depending on how many NICs
2096 you have and where their interrupts are bound, this
2097 option will affect which CPUs will do NFS serving.
2098 Note: this parameter cannot be changed while the
2099 NFS server is running.
2101 auto the server chooses an appropriate mode
2102 automatically using heuristics
2103 global a single global pool contains all CPUs
2104 percpu one pool for each CPU
2105 pernode one pool for each NUMA node (equivalent
2106 to global on non-NUMA machines)
2108 swiotlb= [IA-64] Number of I/O TLB slabs
2112 sym53c416= [HW,SCSI]
2113 See header of drivers/scsi/sym53c416.c.
2115 sysrq_always_enabled
2117 Ignore sysrq setting - this boot parameter will
2118 neutralize any effect of /proc/sys/kernel/sysrq.
2119 Useful for debugging.
2122 See header of drivers/scsi/t128.c.
2126 thash_entries= [KNL,NET]
2127 Set number of hash buckets for TCP connection
2129 thermal.act= [HW,ACPI]
2130 -1: disable all active trip points in all thermal zones
2131 <degrees C>: override all lowest active trip points
2133 thermal.crt= [HW,ACPI]
2134 -1: disable all critical trip points in all thermal zones
2135 <degrees C>: lower all critical trip points
2137 thermal.nocrt= [HW,ACPI]
2138 Set to disable actions on ACPI thermal zone
2139 critical and hot trip points.
2141 thermal.off= [HW,ACPI]
2142 1: disable ACPI thermal control
2144 thermal.psv= [HW,ACPI]
2145 -1: disable all passive trip points
2146 <degrees C>: override all passive trip points to this value
2148 thermal.tzp= [HW,ACPI]
2149 Specify global default ACPI thermal zone polling rate
2150 <deci-seconds>: poll all this frequency
2151 0: no polling (default)
2153 tipar.timeout= [HW,PPT]
2154 Set communications timeout in tenths of a second
2157 tipar.delay= [HW,PPT]
2158 Set inter-bit delay in microseconds (default 10).
2161 See comment before function dc390_setup() in
2162 drivers/scsi/tmscsim.c.
2166 trix= [HW,OSS] MediaTrix AudioTrix Pro
2168 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2170 turbografx.map[2|3]= [HW,JOY]
2171 TurboGraFX parallel port interface
2173 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2174 See also Documentation/input/joystick-parport.txt
2176 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2177 See header of drivers/scsi/u14-34f.c.
2186 [USB] Ignore overcurrent events (default N).
2187 Some badly-designed motherboards generate lots of
2188 bogus events, for ports that aren't wired to
2189 anything. Set this parameter to avoid log spamming.
2190 Note that genuine overcurrent events won't be
2195 Set unknown_nmi_panic=1 early on boot.
2197 usbcore.autosuspend=
2198 [USB] The autosuspend time delay (in seconds) used
2199 for newly-detected USB devices (default 2). This
2200 is the time required before an idle device will be
2201 autosuspended. Devices for which the delay is set
2202 to a negative value won't be autosuspended at all.
2205 [USBHID] The interval which mice are to be polled at.
2207 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2208 kernel's map of available physical RAM.
2210 vdso= [X86-32,SH,x86-64]
2211 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2212 vdso=1: enable VDSO (default)
2213 vdso=0: disable VDSO mapping
2215 vdso32= [X86-32,X86-64]
2216 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2217 vdso32=1: enable 32-bit VDSO (default)
2218 vdso32=0: disable 32-bit VDSO mapping
2221 vector=percpu: enable percpu vector domain
2223 video= [FB] Frame buffer configuration
2224 See Documentation/fb/modedb.txt.
2226 vga= [BOOT,X86-32] Select a particular video mode
2227 See Documentation/i386/boot.txt and
2228 Documentation/svga.txt.
2229 Use vga=ask for menu.
2230 This is actually a boot loader parameter; the value is
2231 passed to the kernel using a special protocol.
2233 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2234 size of <nn>. This can be used to increase the
2235 minimum size (128MB on x86). It can also be used to
2236 decrease the size and leave more room for directly
2239 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2242 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2245 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2248 waveartist= [HW,OSS]
2249 Format: <io>,<irq>,<dma>,<dma2>
2252 See header of drivers/scsi/wd33c93.c.
2255 See header of drivers/scsi/wd7000.c.
2258 See Documentation/watchdog/wdt.txt.
2260 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2261 xd_geo= See header of drivers/block/xd.c.
2263 xirc2ps_cs= [NET,PCMCIA]
2265 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2267 norandmaps Don't use address space randomization
2268 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2270 ______________________________________________________________________
2274 Add documentation for ALSA options.
2275 Add more DRM drivers.