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, 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 old_ordering causes the ACPI 1.0 ordering of the _PTS
156 control method, wrt putting devices into low power
157 states, to be enforced (the ACPI 2.0 ordering of _PTS is
160 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
161 Format: { level | edge | high | low }
163 acpi_irq_balance [HW,ACPI]
164 ACPI will balance active IRQs
167 acpi_irq_nobalance [HW,ACPI]
168 ACPI will not move active IRQs (default)
171 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
173 Format: <irq>,<irq>...
175 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
176 Format: <irq>,<irq>...
178 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
180 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
181 Format: To spoof as Windows 98: ="Microsoft Windows"
183 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
184 acpi_osi="string1" # add string1 -- only one string
185 acpi_osi="!string2" # remove built-in string2
186 acpi_osi= # disable all strings
188 acpi_serialize [HW,ACPI] force serialization of AML methods
190 acpi_skip_timer_override [HW,ACPI]
191 Recognize and ignore IRQ0/pin2 Interrupt Override.
192 For broken nForce2 BIOS resulting in XT-PIC timer.
193 acpi_use_timer_override [HW,ACPI}
194 Use timer override. For some broken Nvidia NF5 boards
195 that require a timer override, but don't have
198 acpi.debug_layer= [HW,ACPI]
200 Each bit of the <int> indicates an ACPI debug layer,
201 1: enable, 0: disable. It is useful for boot time
202 debugging. After system has booted up, it can be set
203 via /sys/module/acpi/parameters/debug_layer.
204 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
205 Available bits (add the numbers together) to enable debug output
206 for specific parts of the ACPI subsystem:
207 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
208 0x10 namespace 0x20 parser 0x40 dispatcher
209 0x80 executer 0x100 resources 0x200 acpica debugger
210 0x400 os services 0x800 acpica disassembler.
211 The number can be in decimal or prefixed with 0x in hex.
212 Warning: Many of these options can produce a lot of
213 output and make your system unusable. Be very careful.
215 acpi.debug_level= [HW,ACPI]
217 Each bit of the <int> indicates an ACPI debug level,
218 1: enable, 0: disable. It is useful for boot time
219 debugging. After system has booted up, it can be set
220 via /sys/module/acpi/parameters/debug_level.
221 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
222 Available bits (add the numbers together) to enable different
223 debug output levels of the ACPI subsystem:
224 0x01 error 0x02 warn 0x04 init 0x08 debug object
225 0x10 info 0x20 init names 0x40 parse 0x80 load
226 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
227 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
228 0x10000 resources 0x20000 user requests 0x40000 package.
229 The number can be in decimal or prefixed with 0x in hex.
230 Warning: Many of these options can produce a lot of
231 output and make your system unusable. Be very careful.
233 acpi_pm_good [X86-32,X86-64]
234 Override the pmtimer bug detection: force the kernel
235 to assume that this machine's pmtimer latches its value
236 and always returns good values.
239 { off | try_unsupported }
240 off: disable AGP support
241 try_unsupported: try to drive unsupported chipsets
242 (may crash computer or cause data corruption)
244 enable_timer_pin_1 [i386,x86-64]
245 Enable PIN 1 of APIC timer
246 Can be useful to work around chipset bugs
247 (in particular on some ATI chipsets).
248 The kernel tries to set a reasonable default.
250 disable_timer_pin_1 [i386,x86-64]
251 Disable PIN 1 of APIC timer
252 Can be useful to work around chipset bugs.
255 Format: <io>,<irq>,<dma>,<dma2>,<type>
258 See header of drivers/scsi/advansys.c.
260 advwdt= [HW,WDT] Advantech WDT
261 Format: <iostart>,<iostop>
263 aedsp16= [HW,OSS] Audio Excel DSP 16
264 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
265 See also header of sound/oss/aedsp16.c.
268 See Documentation/scsi/aha152x.txt.
271 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
274 See Documentation/scsi/aic7xxx.txt.
277 See Documentation/scsi/aic79xx.txt.
279 amd_iommu= [HW,X86-84]
280 Pass parameters to the AMD IOMMU driver in the system.
282 isolate - enable device isolation (each device, as far
283 as possible, will get its own protection
285 amd_iommu_size= [HW,X86-64]
286 Define the size of the aperture for the AMD IOMMU
287 driver. Possible values are:
288 '32M', '64M' (default), '128M', '256M', '512M', '1G'
290 amijoy.map= [HW,JOY] Amiga joystick support
291 Map of devices attached to JOY0DAT and JOY1DAT
293 See also Documentation/kernel/input/joystick.txt
295 analog.map= [HW,JOY] Analog joystick and gamepad support
296 Specifies type or capabilities of an analog joystick
297 connected to one of 16 gameports
298 Format: <type1>,<type2>,..<type16>
301 Power management functions (SPARCstation-4/5 + deriv.)
303 Disable APC CPU standby support. SPARCstation-Fox does
304 not play well with APC CPU idle - disable it if you have
305 APC and your system crashes randomly.
307 apic= [APIC,i386] Advanced Programmable Interrupt Controller
308 Change the output verbosity whilst booting
309 Format: { quiet (default) | verbose | debug }
310 Change the amount of debugging information output
311 when initialising the APIC and IO-APIC components.
313 apm= [APM] Advanced Power Management
314 See header of arch/x86/kernel/apm_32.c.
316 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
317 Format: <io>,<irq>,<nodeID>
321 atarimouse= [HW,MOUSE] Atari Mouse
323 atascsi= [HW,SCSI] Atari SCSI
325 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
326 EzKey and similar keyboards
328 atkbd.reset= [HW] Reset keyboard during initialization
330 atkbd.set= [HW] Select keyboard code set
331 Format: <int> (2 = AT (default), 3 = PS/2)
333 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
336 atkbd.softraw= [HW] Choose between synthetic and real raw mode
337 Format: <bool> (0 = real, 1 = synthetic (default))
339 atkbd.softrepeat= [HW]
340 Use software keyboard repeat
344 baycom_epp= [HW,AX25]
347 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
349 See header of drivers/net/hamradio/baycom_par.c.
351 baycom_ser_fdx= [HW,AX25]
352 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
353 Format: <io>,<irq>,<mode>[,<baud>]
354 See header of drivers/net/hamradio/baycom_ser_fdx.c.
356 baycom_ser_hdx= [HW,AX25]
357 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
358 Format: <io>,<irq>,<mode>
359 See header of drivers/net/hamradio/baycom_ser_hdx.c.
361 boot_delay= Milliseconds to delay each printk during boot.
362 Values larger than 10 seconds (10000) are changed to
366 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
367 bttv.radio= Most important insmod options are available as
369 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
370 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
373 See drivers/scsi/BusLogic.c, comment before function
374 BusLogic_ParseDriverOptions().
376 c101= [NET] Moxa C101 synchronous serial card
378 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
379 Sometimes CPU hardware bugs make them report the cache
380 size incorrectly. The kernel will attempt work arounds
381 to fix known problems, but for some CPUs it is not
382 possible to determine what the correct size should be.
383 This option provides an override for these situations.
385 security= [SECURITY] Choose a security module to enable at boot.
386 If this boot parameter is not specified, only the first
387 security module asking for security registration will be
388 loaded. An invalid security module name will be treated
389 as if no module has been chosen.
392 [SECURITY] Disable capabilities. This would normally
393 be used only if an alternative security model is to be
394 configured. Potentially dangerous and should only be
395 used if you are entirely sure of the consequences.
397 ccw_timeout_log [S390]
398 See Documentation/s390/CommonIO for details.
400 cgroup_disable= [KNL] Disable a particular controller
401 Format: {name of the controller(s) to disable}
402 {Currently supported controllers - "memory"}
404 checkreqprot [SELINUX] Set initial checkreqprot flag value.
405 Format: { "0" | "1" }
406 See security/selinux/Kconfig help text.
407 0 -- check protection applied by kernel (includes
408 any implied execute protection).
409 1 -- check protection requested by application.
410 Default value is set via a kernel config option.
411 Value can be changed at runtime via
412 /selinux/checkreqprot.
415 See Documentation/s390/CommonIO for details.
417 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
419 Forces specified clocksource (if available) to be used
420 when calculating gettimeofday(). If specified
421 clocksource is not available, it defaults to PIT.
422 Format: { pit | tsc | cyclone | pmtmr }
424 clocksource= [GENERIC_TIME] Override the default clocksource
426 Override the default clocksource and use the clocksource
427 with the name specified.
428 Some clocksource names to choose from, depending on
430 [all] jiffies (this is the base, fallback clocksource)
432 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
433 pxa_timer,timer3,32k_counter,timer0_1
435 [X86-32] pit,hpet,tsc,vmi-timer;
436 scx200_hrt on Geode; cyclone on IBM x440
444 clearcpuid=BITNUM [X86]
445 Disable CPUID feature X for the kernel. See
446 include/asm-x86/cpufeature.h for the valid bit numbers.
447 Note the Linux specific bits are not necessarily
448 stable over kernel options, but the vendor specific
450 Also note that user programs calling CPUID directly
451 or using the feature without checking anything
452 will still see it. This just prevents it from
453 being used by the kernel or shown in /proc/cpuinfo.
454 Also note the kernel might malfunction if you disable
457 code_bytes [IA32/X86_64] How many bytes of object code to print
464 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
465 over the 8254 in addition to over the IO-APIC. The
466 kernel tries to set a sensible default.
468 hpet= [X86-32,HPET] option to control HPET usage
469 Format: { enable (default) | disable | force }
470 disable: disable HPET and use PIT instead
471 force: allow force enabled of undocumented chips (ICH4,
474 com20020= [HW,NET] ARCnet - COM20020 chipset
476 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
478 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
482 ARCnet - COM90xx chipset (memory-mapped buffers)
483 Format: <io>[,<irq>[,<memstart>]]
485 condev= [HW,S390] console device
488 console= [KNL] Output console device and options.
490 tty<n> Use the virtual console device <n>.
494 Use the specified serial port. The options are of
495 the form "bbbbpnf", where "bbbb" is the baud rate,
496 "p" is parity ("n", "o", or "e"), "n" is number of
497 bits, and "f" is flow control ("r" for RTS or
498 omit it). Default is "9600n8".
500 See Documentation/serial-console.txt for more
502 Documentation/networking/netconsole.txt for an
505 uart[8250],io,<addr>[,options]
506 uart[8250],mmio,<addr>[,options]
507 Start an early, polled-mode console on the 8250/16550
508 UART at the specified I/O port or MMIO address,
509 switching to the matching ttyS device later. The
510 options are the same as for ttyS, above.
512 If the device connected to the port is not a TTY but a braille
513 device, prepend "brl," before the device type, for instance
515 For now, only VisioBraille is supported.
517 earlycon= [KNL] Output early console device and options.
518 uart[8250],io,<addr>[,options]
519 uart[8250],mmio,<addr>[,options]
520 Start an early, polled-mode console on the 8250/16550
521 UART at the specified I/O port or MMIO address.
522 The options are the same as for ttyS, above.
525 [HW] Never suspend the console
526 Disable suspending of consoles during suspend and
527 hibernate operations. Once disabled, debugging
528 messages can reach various consoles while the rest
529 of the system is being put to sleep (ie, while
530 debugging driver suspend/resume hooks). This may
531 not work reliably with all consoles, but is known
532 to work with serial and VGA consoles.
534 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
536 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
538 crashkernel=nn[KMG]@ss[KMG]
539 [KNL] Reserve a chunk of physical memory to
540 hold a kernel to switch to with kexec on panic.
542 crashkernel=range1:size1[,range2:size2,...][@offset]
543 [KNL] Same as above, but depends on the memory
544 in the running system. The syntax of range is
545 start-[end] where start and end are both
546 a memory unit (amount[KMG]). See also
547 Documentation/kdump/kdump.txt for a example.
550 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
555 cs89x0_media= [HW,NET]
556 Format: { rj45 | aui | bnc }
559 See header of drivers/s390/block/dasd_devmap.c.
561 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
562 (one device per port)
563 Format: <port#>,<type>
564 See also Documentation/input/joystick-parport.txt
566 debug [KNL] Enable kernel debugging (events log level).
569 [KNL] verbose self-tests
571 Print debugging info while doing the locking API
573 We default to 0 (no extra messages), setting it to
574 1 will print _a lot_ more information - normally
575 only useful to kernel developers.
577 debug_objects [KNL] Enable object debugging
579 debugpat [X86] Enable PAT debugging
581 decnet.addr= [HW,NET]
582 Format: <area>[,<node>]
583 See also Documentation/networking/decnet.txt.
586 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
587 Change the default blue palette of the console.
588 This is a 16-member array composed of values
592 Format: <green0>,<green1>,<green2>,...,<green15>
593 Change the default green palette of the console.
594 This is a 16-member array composed of values
598 Format: <red0>,<red1>,<red2>,...,<red15>
599 Change the default red palette of the console.
600 This is a 16-member array composed of values
606 Set system-wide default UTF-8 mode for all tty's.
607 Default is 1, i.e. UTF-8 mode is enabled for all
608 newly opened terminals.
611 Set number of hash buckets for dentry cache.
614 IO parameters + enable/disable command.
616 digiepca= [HW,SERIAL]
617 See drivers/char/README.epca and
618 Documentation/digiepca.txt.
620 disable_mtrr_cleanup [X86]
621 enable_mtrr_cleanup [X86]
622 The kernel tries to adjust MTRR layout from continuous
623 to discrete, to make X server driver able to add WB
624 entry later. This parameter enables/disables that.
626 mtrr_chunk_size=nn[KMG] [X86]
627 used for mtrr cleanup. It is largest continous chunk
628 that could hold holes aka. UC entries.
630 mtrr_gran_size=nn[KMG] [X86]
631 Used for mtrr cleanup. It is granularity of mtrr block.
633 Large value could prevent small alignment from
636 mtrr_spare_reg_nr=n [X86]
638 Range: 0,7 : spare reg number
640 Used for mtrr cleanup. It is spare mtrr entries number.
641 Set to 2 or more if your graphical card needs more.
643 disable_mtrr_trim [X86, Intel and AMD only]
644 By default the kernel will trim any uncacheable
645 memory out of your available memory pool based on
646 MTRR settings. This parameter disables that behavior,
647 possibly causing your machine to run very slowly.
649 dmasound= [HW,OSS] Sound subsystem buffers
655 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
657 earlyprintk=serial[,ttySn[,baudrate]]
659 Append ",keep" to not disable it when the real console
662 Only vga or serial at a time, not both.
664 Currently only ttyS0 and ttyS1 are supported.
666 Interaction with the standard serial driver is not
669 The VGA output is eventually overwritten by the real
675 Format: {"off" | "on" | "skip[mbr]"}
677 eisa_irq_edge= [PARISC,HW]
678 See header of drivers/parisc/eisa.c.
681 See comment before function elanfreq_setup() in
682 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
685 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
686 See Documentation/block/as-iosched.txt and
687 Documentation/block/deadline-iosched.txt for details.
689 elfcorehdr= [X86-32, X86_64]
690 Specifies physical address of start of kernel core
691 image elf header. Generally kexec loader will
692 pass this option to capture kernel.
693 See Documentation/kdump/kdump.txt for details.
695 enforcing [SELINUX] Set initial enforcing status.
697 See security/selinux/Kconfig help text.
698 0 -- permissive (log only, no denials).
699 1 -- enforcing (deny and log).
701 Value can be changed at runtime via /selinux/enforce.
704 Format: <spdif>,[<nomix>,[<amplifier>]]
705 See also header of sound/oss/es1371.c.
707 ether= [HW,NET] Ethernet cards parameters
708 This option is obsoleted by the "netdev=" option, which
709 has equivalent usage. See its documentation for details.
711 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
716 fail_make_request=[KNL]
717 General fault injection mechanism.
718 Format: <interval>,<probability>,<space>,<times>
719 See also /Documentation/fault-injection/.
722 See header of drivers/scsi/fd_mcs.c.
725 See header of drivers/scsi/fdomain.c.
728 See Documentation/floppy.txt.
730 force_pal_cache_flush
731 [IA-64] Avoid check_sal_cache_flush which may hang on
732 buggy SAL_CACHE_FLUSH implementations. Using this
733 parameter will force ia64_sal_cache_flush to call
734 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
737 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
738 support via parallel port (up to 5 devices per port)
739 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
740 See also Documentation/input/joystick-parport.txt
744 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
749 See header of drivers/scsi/gdth.c.
751 gpt [EFI] Forces disk with valid GPT signature but
752 invalid Protective MBR to be treated as GPT.
756 hashdist= [KNL,NUMA] Large hashes allocated during boot
757 are distributed across NUMA nodes. Defaults on
758 for IA-64, off otherwise.
759 Format: 0 | 1 (for off | on)
761 hcl= [IA-64] SGI's Hardware Graph compatibility layer
763 hd= [EIDE] (E)IDE hard drive subsystem geometry
764 Format: <cyl>,<head>,<sect>
766 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
767 size of <nn>. This works even on boxes that have no
768 highmem otherwise. This also works to reduce highmem
769 size on bigger boxes.
771 highres= [KNL] Enable/disable high resolution timer mode.
772 Valid parameters: "on", "off"
776 See Documentation/isdn/README.HiSax.
778 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
779 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
780 On x86-64 and powerpc, this option can be specified
781 multiple times interleaved with hugepages= to reserve
782 huge pages of different sizes. Valid pages sizes on
783 x86-64 are 2M (when the CPU supports "pse") and 1G
784 (when the CPU supports the "pdpe1gb" cpuinfo flag)
785 Note that 1GB pages can only be allocated at boot time
786 using hugepages= and not freed afterwards.
788 [same as hugepagesz=] The size of the default
789 HugeTLB page size. This is the size represented by
790 the legacy /proc/ hugepages APIs, used for SHM, and
791 default size when mounting hugetlbfs filesystems.
792 Defaults to the default architecture's huge page size
795 i8042.direct [HW] Put keyboard port into non-translated mode
796 i8042.dumbkbd [HW] Pretend that controller can only read data from
797 keyboard and cannot control its state
798 (Don't attempt to blink the leds)
799 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
800 i8042.nokbd [HW] Don't check/create keyboard port
801 i8042.noloop [HW] Disable the AUX Loopback command while probing
803 i8042.nomux [HW] Don't check presence of an active multiplexing
805 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
808 [HW] Frequency with which keyboard LEDs should blink
809 when kernel panics (default is 0.5 sec)
810 i8042.reset [HW] Reset the controller during init and cleanup
811 i8042.unlock [HW] Unlock (ignore) the keylock
815 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
816 indicates that the driver is running on unsupported
818 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
819 does not match list of supported models.
821 [HW] Report power status in /proc/i8k
822 (disabled by default)
823 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
826 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
827 See Documentation/mca.txt.
830 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
832 ide= [HW] (E)IDE subsystem
833 Format: ide=nodma or ide=doubler
834 See Documentation/ide/ide.txt.
836 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
837 See Documentation/ide/ide.txt.
840 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
841 Poll forces a polling idle loop that can slightly improves the performance
842 of waking up a idle CPU, but will use a lot of power and make the system
843 run hot. Not recommended.
844 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
845 to not use it because it doesn't save as much power as a normal idle
846 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
848 idle=halt. Halt is forced to be used for CPU idle.
849 In such case C2/C3 won't be used again.
850 idle=nomwait. Disable mwait for CPU C-states
852 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
853 Claim all unknown PCI IDE storage controllers.
855 ignore_loglevel [KNL]
856 Ignore loglevel setting - this will print /all/
857 kernel messages to the console. Useful for debugging.
860 Set number of hash buckets for inode cache.
863 See header of drivers/scsi/in2000.c.
867 Run specified binary instead of /sbin/init as init
870 initcall_debug [KNL] Trace initcalls as they are executed. Useful
871 for working out where the kernel is dying during
874 initrd= [BOOT] Specify the location of the initial ramdisk
876 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
894 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
896 Disable intel iommu driver.
897 igfx_off [Default Off]
898 By default, gfx is mapped as normal device. If a gfx
899 device has a dedicated DMAR unit, the DMAR unit is
900 bypassed by not enabling DMAR with this option. In
901 this case, gfx device will use physical address for
904 With this option iommu will not optimize to look
905 for io virtual address below 32 bit forcing dual
906 address cycle on pci bus for cards supporting greater
907 than 32 bit addressing. The default is to look
908 for translation below 32 bit and if not available
909 then look in the higher range.
911 With this option on every unmap_single operation will
912 result in a hardware IOTLB flush operation as opposed
913 to batching them for performance.
915 io_delay= [X86-32,X86-64] I/O delay method
917 Standard port 0x80 based delay
919 Alternate port 0xed based delay (needed on some systems)
921 Simple two microseconds delay
925 io7= [HW] IO7 for Marvel based alpha systems
926 See comment before marvel_specify_io7 in
927 arch/alpha/kernel/core_marvel.c.
930 See Documentation/filesystems/nfsroot.txt.
932 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
933 See comment before ip2_setup() in
934 drivers/char/ip2/ip2base.c.
936 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
937 See header of drivers/scsi/ips.c.
939 ports= [IP_VS_FTP] IPVS ftp helper module
941 Up to 8 (IP_VS_APP_MAX_PORTS) ports
943 Format: <port>,<port>....
946 When an interrupt is not handled search all handlers
947 for it. Intended to get systems with badly broken
951 When an interrupt is not handled search all handlers
952 for it. Also check all handlers each timer
953 interrupt. Intended to get systems with badly broken
957 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
959 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
961 <cpu number>,...,<cpu number>
963 <cpu number>-<cpu number> (must be a positive range in ascending order)
965 <cpu number>,...,<cpu number>-<cpu number>
966 This option can be used to specify one or more CPUs
967 to isolate from the general SMP balancing and scheduling
968 algorithms. The only way to move a process onto or off
969 an "isolated" CPU is via the CPU affinity syscalls.
970 <cpu number> begins at 0 and the maximum value is
971 "number of CPUs in system - 1".
973 This option is the preferred way to isolate CPUs. The
974 alternative -- manually setting the CPU mask of all
975 tasks in the system -- can cause problems and
976 suboptimal load balancer performance.
980 js= [HW,JOY] Analog joystick
981 See Documentation/input/joystick.txt.
983 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
984 specifies the amount of memory usable by the kernel
985 for non-movable allocations. The requested amount is
986 spread evenly throughout all nodes in the system. The
987 remaining memory in each node is used for Movable
988 pages. In the event, a node is too small to have both
989 kernelcore and Movable pages, kernelcore pages will
990 take priority and other nodes will have a larger number
991 of kernelcore pages. The Movable zone is used for the
992 allocation of pages that may be reclaimed or moved
993 by the page migration subsystem. This means that
994 HugeTLB pages may not be allocated from this zone.
995 Note that allocations like PTEs-from-HighMem still
996 use the HighMem zone if it exists, and the Normal
999 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1000 is similar to kernelcore except it specifies the
1001 amount of memory used for migratable allocations.
1002 If both kernelcore and movablecore is specified,
1003 then kernelcore will be at *least* the specified
1004 value but may be more. If movablecore on its own
1005 is specified, the administrator must be careful
1006 that the amount of memory usable for all allocations
1011 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1014 kgdboc= [HW] kgdb over consoles.
1015 Requires a tty driver that supports console polling.
1016 (only serial suported for now)
1017 Format: <serial_device>[,baud]
1023 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1026 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1029 libata.dma= [LIBATA] DMA control
1030 libata.dma=0 Disable all PATA and SATA DMA
1031 libata.dma=1 PATA and SATA Disk DMA only
1032 libata.dma=2 ATAPI (CDROM) DMA only
1033 libata.dma=4 Compact Flash DMA only
1034 Combinations also work, so libata.dma=3 enables DMA
1035 for disks and CDROMs, but not CFs.
1037 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1041 libata.force= [LIBATA] Force configurations. The format is comma
1042 separated list of "[ID:]VAL" where ID is
1043 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1044 matching port, link or device. Basically, it matches
1045 the ATA ID string printed on console by libata. If
1046 the whole ID part is omitted, the last PORT and DEVICE
1047 values are used. If ID hasn't been specified yet, the
1048 configuration applies to all ports, links and devices.
1050 If only DEVICE is omitted, the parameter applies to
1051 the port and all links and devices behind it. DEVICE
1052 number of 0 either selects the first device or the
1053 first fan-out link behind PMP device. It does not
1054 select the host link. DEVICE number of 15 selects the
1055 host link and device attached to it.
1057 The VAL specifies the configuration to force. As long
1058 as there's no ambiguity shortcut notation is allowed.
1059 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1060 The following configurations can be forced.
1062 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1063 Any ID with matching PORT is used.
1065 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1067 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1068 udma[/][16,25,33,44,66,100,133] notation is also
1071 * [no]ncq: Turn on or off NCQ.
1073 If there are multiple matching configurations changing
1074 the same attribute, the last one is used.
1076 load_ramdisk= [RAM] List of ramdisks to load from floppy
1077 See Documentation/ramdisk.txt.
1079 lockd.nlm_grace_period=P [NFS] Assign grace period.
1082 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1085 lockd.nlm_timeout=T [NFS] Assign timeout value.
1088 lockd.nlm_udpport=M [NFS] Assign UDP port.
1091 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1094 loglevel= All Kernel Messages with a loglevel smaller than the
1095 console loglevel will be printed to the console. It can
1096 also be changed with klogd or other programs. The
1097 loglevels are defined as follows:
1099 0 (KERN_EMERG) system is unusable
1100 1 (KERN_ALERT) action must be taken immediately
1101 2 (KERN_CRIT) critical conditions
1102 3 (KERN_ERR) error conditions
1103 4 (KERN_WARNING) warning conditions
1104 5 (KERN_NOTICE) normal but significant condition
1105 6 (KERN_INFO) informational
1106 7 (KERN_DEBUG) debug-level messages
1108 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1109 Format: { n | nk | nM }
1110 n must be a power of two. The default size
1111 is set in the kernel config file.
1113 logo.nologo [FB] Disables display of the built-in Linux logo.
1114 This may be used to provide more screen space for
1115 kernel log messages and is useful when debugging
1116 kernel boot problems.
1118 lp=0 [LP] Specify parallel ports to use, e.g,
1119 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1120 lp=reset first parallel port). 'lp=0' disables the
1121 lp=auto printer driver. 'lp=reset' (which can be
1122 specified in addition to the ports) causes
1123 attached printers to be reset. Using
1124 lp=port1,port2,... specifies the parallel ports
1125 to associate lp devices with, starting with
1126 lp0. A port specification may be 'none' to skip
1127 that lp device, or a parport name such as
1128 'parport0'. Specifying 'lp=auto' instead of a
1129 port specification list means that device IDs
1130 from each port should be examined, to see if
1131 an IEEE 1284-compliant printer is attached; if
1132 so, the driver will manage that printer.
1133 See also header of drivers/char/lp.c.
1136 Sets loops_per_jiffy to given constant, thus avoiding
1137 time-consuming boot-time autodetection (up to 250 ms per
1138 CPU). 0 enables autodetection (default). To determine
1139 the correct value for your kernel, boot with normal
1140 autodetection and see what value is printed. Note that
1141 on SMP systems the preset will be applied to all CPUs,
1142 which is likely to cause problems if your CPUs need
1143 significantly divergent settings. An incorrect value
1144 will cause delays in the kernel to be wrong, leading to
1145 unpredictable I/O errors and other breakage. Although
1146 unlikely, in the extreme case this might damage your
1150 Format: <io>,<irq>,<dma>
1152 mac5380= [HW,SCSI] Format:
1153 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1155 machvec= [IA64] Force the use of a particular machine-vector
1156 (machvec) in a generic kernel.
1157 Example: machvec=hpzx1_swiotlb
1159 max_loop= [LOOP] Maximum number of loopback devices that can
1163 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1164 should make use of. maxcpus=n : n >= 0 limits the
1165 kernel to using 'n' processors. n=0 is a special case,
1166 it is equivalent to "nosmp", which also disables
1169 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1170 equal to this physical address is ignored.
1172 max_luns= [SCSI] Maximum number of LUNs to probe.
1173 Should be between 1 and 2^32-1.
1176 [SCSI] Maximum number of LUNs received.
1177 Should be between 1 and 16384.
1181 mce [X86-32] Machine Check Exception
1183 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1185 md= [HW] RAID subsystems devices and level
1186 See Documentation/md.txt.
1189 Format: <first>,<last>
1190 Specifies range of consoles to be captured by the MDA.
1192 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1193 Amount of memory to be used when the kernel is not able
1194 to see the whole system memory or for test.
1195 [X86-32] Use together with memmap= to avoid physical
1196 address space collisions. Without memmap= PCI devices
1197 could be placed at addresses belonging to unused RAM.
1199 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1202 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1203 E820 memory map, as specified by the user.
1204 Such memmap=exactmap lines can be constructed based on
1205 BIOS output or other requirements. See the memmap=nn@ss
1208 memmap=nn[KMG]@ss[KMG]
1209 [KNL] Force usage of a specific region of memory
1210 Region of memory to be used, from ss to ss+nn.
1212 memmap=nn[KMG]#ss[KMG]
1213 [KNL,ACPI] Mark specific memory as ACPI data.
1214 Region of memory to be used, from ss to ss+nn.
1216 memmap=nn[KMG]$ss[KMG]
1217 [KNL,ACPI] Mark specific memory as reserved.
1218 Region of memory to be used, from ss to ss+nn.
1219 Example: Exclude memory from 0x18690000-0x1869ffff
1220 memmap=64K$0x18690000
1222 memmap=0x10000$0x18690000
1224 memtest= [KNL,X86] Enable memtest
1226 range: 0,4 : pattern number
1227 default : 0 <disable>
1229 meye.*= [HW] Set MotionEye Camera parameters
1230 See Documentation/video4linux/meye.txt.
1232 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1233 Multi-Function General Purpose Timers on AMD Geode
1236 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1237 the BIOS has incorrectly applied a workaround. TinyBIOS
1238 version 0.98 is known to be affected, 0.99 fixes the
1239 problem by letting the user disable the workaround.
1244 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1245 parameter allows control of the logging verbosity for
1246 the additional memory initialisation checks. A value
1247 of 0 disables mminit logging and a level of 4 will
1248 log everything. Information is printed at KERN_DEBUG
1249 so loglevel=8 may also need to be specified.
1252 [MOUSE] Maximum time between finger touching and
1253 leaving touchpad surface for touch to be considered
1254 a tap and be reported as a left button click (for
1255 touchpads working in absolute mode only).
1257 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1258 reporting absolute coordinates, such as tablets
1259 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1260 reporting absolute coordinates, such as tablets
1265 MTD_Partition= [MTD]
1266 Format: <name>,<region-number>,<size>,<offset>
1268 MTD_Region= [MTD] Format:
1269 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1272 See drivers/mtd/cmdlinepart.c.
1275 ARM/S3C2412 JIVE boot control
1277 See arch/arm/mach-s3c2412/mach-jive.c
1279 mtouchusb.raw_coordinates=
1280 [HW] Make the MicroTouch USB driver use raw coordinates
1281 ('y', default) or cooked coordinates ('n')
1283 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1286 See header of drivers/scsi/NCR_D700.c.
1290 ncr53c400= [HW,SCSI]
1292 ncr53c400a= [HW,SCSI]
1294 ncr53c406a= [HW,SCSI]
1296 ncr53c8xx= [HW,SCSI]
1298 netdev= [NET] Network devices parameters
1299 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1300 Note that mem_start is often overloaded to mean
1301 something different and driver-specific.
1302 This usage is only documented in each driver source
1306 [NETFILTER] Enable connection tracking flow accounting
1307 0 to disable accounting
1308 1 to enable accounting
1309 Default value depends on CONFIG_NF_CT_ACCT that is
1310 going to be removed in 2.6.29.
1313 See Documentation/filesystems/nfsroot.txt.
1315 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1316 See Documentation/filesystems/nfsroot.txt.
1318 nfs.callback_tcpport=
1319 [NFS] set the TCP port on which the NFSv4 callback
1320 channel should listen.
1322 nfs.idmap_cache_timeout=
1323 [NFS] set the maximum lifetime for idmapper cache
1327 [NFS] enable 64-bit inode numbers.
1328 If zero, the NFS client will fake up a 32-bit inode
1329 number for the readdir() and stat() syscalls instead
1330 of returning the full 64-bit number.
1331 The default is to return 64-bit inode numbers.
1333 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1334 when a NMI is triggered.
1335 Format: [state][,regs][,debounce][,die]
1337 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1339 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1340 emulation library even if a 387 maths coprocessor
1343 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1344 caches in the slab allocator. Saves per-node memory,
1345 but will impact performance.
1349 noapic [SMP,APIC] Tells the kernel to not make use of any
1350 IOAPICs that may be present in the system.
1352 nobats [PPC] Do not use BATs for mapping kernel lowmem
1353 on "Classic" PPC cores.
1357 nodelayacct [KNL] Disable per-task delay accounting
1359 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1361 noefi [X86-32,X86-64] Disable EFI runtime services support.
1365 noexec [X86-32,X86-64]
1366 On X86-32 available only on PAE configured kernels.
1367 noexec=on: enable non-executable mappings (default)
1368 noexec=off: disable non-executable mappings
1371 This affects only 32-bit executables.
1372 noexec32=on: enable non-executable mappings (default)
1373 read doesn't imply executable mappings
1374 noexec32=off: disable non-executable mappings
1375 read implies executable mappings
1377 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1378 register save and restore. The kernel will only save
1379 legacy floating-point registers on task switch.
1381 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1385 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1386 instruction doesn't work correctly and not to
1389 nohalt [IA-64] Tells the kernel not to use the power saving
1390 function PAL_HALT_LIGHT when idle. This increases
1391 power-consumption. On the positive side, it reduces
1392 interrupt wake-up latency, which may improve performance
1393 in certain environments such as networked servers or
1396 nohz= [KNL] Boottime enable/disable dynamic ticks
1397 Valid arguments: on, off
1400 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1402 noirqdebug [X86-32] Disables the code which attempts to detect and
1403 disable unhandled interrupt sources.
1405 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1406 broken timer IRQ sources.
1408 noisapnp [ISAPNP] Disables ISA PnP code.
1410 noinitrd [RAM] Tells the kernel not to load any configured
1415 nojitter [IA64] Disables jitter checking for ITC timers.
1417 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1419 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1421 noltlbs [PPC] Do not use large page/tlb entries for kernel
1422 lowmem mapping on PPC40x.
1424 nomca [IA-64] Disable machine check abort handling
1426 nomce [X86-32] Machine Check Exception
1428 nomfgpt [X86-32] Disable Multi-Function General Purpose
1429 Timer usage (for AMD Geode machines).
1431 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1433 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1434 with UP alternatives
1436 noresidual [PPC] Don't use residual data on PReP machines.
1438 noresume [SWSUSP] Disables resume and restores original swap
1441 no-scroll [VGA] Disables scrollback.
1442 This is required for the Braillex ib80-piezo Braille
1443 reader made by F.H. Papenmeier (Germany).
1447 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1449 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1450 and disable the IO APIC. legacy for "maxcpus=0".
1452 nosoftlockup [KNL] Disable the soft-lockup detector.
1454 nosync [HW,M68K] Disables sync negotiation for all devices.
1456 notsc [BUGS=X86-32] Disable Time Stamp Counter
1458 nousb [USB] Disable the USB subsystem
1462 nptcg= [IA64] Override max number of concurrent global TLB
1463 purges which is reported from either PAL_VM_SUMMARY or
1466 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1467 one of ['zone', 'node', 'default'] can be specified
1468 This can be set from sysctl after boot.
1469 See Documentation/sysctl/vm.txt for details.
1471 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1473 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1474 Rather than timing out after 20 ms if an EC
1475 command is not properly ACKed, override the length
1476 of the timeout. We have interrupts disabled while
1477 waiting for the ACK, so if this is set too high
1478 interrupts *may* be lost!
1483 oprofile.timer= [HW]
1484 Use timer interrupt instead of performance counters
1486 osst= [HW,SCSI] SCSI Tape Driver
1487 Format: <buffer_size>,<write_threshold>
1488 See also Documentation/scsi/st.txt.
1490 panic= [KNL] Kernel behaviour on panic
1493 parkbd.port= [HW] Parallel port number the keyboard adapter is
1494 connected to, default is 0.
1496 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1497 0 for XT, 1 for AT (default is AT).
1500 parport= [HW,PPT] Specify parallel ports. 0 disables.
1501 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1502 Use 'auto' to force the driver to use any
1503 IRQ/DMA settings detected (the default is to
1504 ignore detected IRQ/DMA settings because of
1505 possible conflicts). You can specify the base
1506 address, IRQ, and DMA settings; IRQ and DMA
1507 should be numbers, or 'auto' (for using detected
1508 settings on that particular port), or 'nofifo'
1509 (to avoid using a FIFO even if it is detected).
1510 Parallel ports are assigned in the order they
1511 are specified on the command line, starting
1514 parport_init_mode= [HW,PPT]
1515 Configure VIA parallel port to operate in
1516 a specific mode. This is necessary on Pegasos
1517 computer where firmware has no options for setting
1518 up parallel port mode and sets it to spp.
1519 Currently this function knows 686a and 8231 chips.
1520 Format: [spp|ps2|epp|ecp|ecpepp]
1522 pas2= [HW,OSS] Format:
1523 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1526 See header of drivers/scsi/pas16.c.
1529 Halt all CPUs after the first oops has been printed for
1530 the specified number of seconds. This is to be used if
1531 your oopses keep scrolling off the screen.
1536 See header of drivers/block/paride/pcd.c.
1537 See also Documentation/paride.txt.
1539 pci=option[,option...] [PCI] various PCI subsystem options:
1540 off [X86-32] don't probe for the PCI bus
1541 bios [X86-32] force use of PCI BIOS, don't access
1542 the hardware directly. Use this if your machine
1543 has a non-standard PCI host bridge.
1544 nobios [X86-32] disallow use of PCI BIOS, only direct
1545 hardware access methods are allowed. Use this
1546 if you experience crashes upon bootup and you
1547 suspect they are caused by the BIOS.
1548 conf1 [X86-32] Force use of PCI Configuration
1550 conf2 [X86-32] Force use of PCI Configuration
1552 noaer [PCIE] If the PCIEAER kernel config parameter is
1553 enabled, this kernel boot option can be used to
1554 disable the use of PCIE advanced error reporting.
1555 nodomains [PCI] Disable support for multiple PCI
1556 root domains (aka PCI segments, in ACPI-speak).
1557 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1559 nomsi [MSI] If the PCI_MSI kernel config parameter is
1560 enabled, this kernel boot option can be used to
1561 disable the use of MSI interrupts system-wide.
1562 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1563 routing table. These calls are known to be buggy
1564 on several machines and they hang the machine
1565 when used, but on other computers it's the only
1566 way to get the interrupt routing table. Try
1567 this option if the kernel is unable to allocate
1568 IRQs or discover secondary PCI buses on your
1570 rom [X86-32] Assign address space to expansion ROMs.
1571 Use with caution as certain devices share
1572 address decoders between ROMs and other
1574 norom [X86-32,X86_64] Do not assign address space to
1575 expansion ROMs that do not already have
1576 BIOS assigned address ranges.
1577 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1578 assigned automatically to PCI devices. You can
1579 make the kernel exclude IRQs of your ISA cards
1581 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1582 of the PIRQ table (normally generated
1583 by the BIOS) if it is outside the
1584 F0000h-100000h range.
1585 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1586 useful if the kernel is unable to find your
1587 secondary buses and you want to tell it
1588 explicitly which ones they are.
1589 assign-busses [X86-32] Always assign all PCI bus
1590 numbers ourselves, overriding
1591 whatever the firmware may have done.
1592 usepirqmask [X86-32] Honor the possible IRQ mask stored
1593 in the BIOS $PIR table. This is needed on
1594 some systems with broken BIOSes, notably
1595 some HP Pavilion N5400 and Omnibook XE3
1596 notebooks. This will have no effect if ACPI
1597 IRQ routing is enabled.
1598 noacpi [X86-32] Do not use ACPI for IRQ routing
1599 or for PCI scanning.
1600 use_crs [X86-32] Use _CRS for PCI resource
1602 routeirq Do IRQ routing for all PCI devices.
1603 This is normally done in pci_enable_device(),
1604 so this option is a temporary workaround
1605 for broken drivers that don't call it.
1606 skip_isa_align [X86] do not align io start addr, so can
1607 handle more pci cards
1608 firmware [ARM] Do not re-enumerate the bus but instead
1609 just use the configuration from the
1610 bootloader. This is currently used on
1611 IXP2000 systems where the bus has to be
1612 configured a certain way for adjunct CPUs.
1613 noearly [X86] Don't do any early type 1 scanning.
1614 This might help on some broken boards which
1615 machine check when some devices' config space
1616 is read. But various workarounds are disabled
1617 and some IOMMU drivers will not work.
1618 bfsort Sort PCI devices into breadth-first order.
1619 This sorting is done to get a device
1620 order compatible with older (<= 2.4) kernels.
1621 nobfsort Don't sort PCI devices into breadth-first order.
1622 cbiosize=nn[KMG] The fixed amount of bus space which is
1623 reserved for the CardBus bridge's IO window.
1624 The default value is 256 bytes.
1625 cbmemsize=nn[KMG] The fixed amount of bus space which is
1626 reserved for the CardBus bridge's memory
1627 window. The default value is 64 megabytes.
1629 pcmv= [HW,PCMCIA] BadgePAD 4
1632 See Documentation/paride.txt.
1634 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1637 See arch/parisc/kernel/pdc_chassis.c
1640 See Documentation/paride.txt.
1643 See Documentation/paride.txt.
1645 pirq= [SMP,APIC] Manual mp-table setup
1646 See Documentation/i386/IO-APIC.txt.
1648 plip= [PPT,NET] Parallel port network link
1649 Format: { parport<nr> | timid | 0 }
1650 See also Documentation/parport.txt.
1652 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1653 Override pmtimer IOPort with a hex value.
1660 { on | off | curr | res | no-curr | no-res }
1663 [ISAPNP] Exclude IRQs for the autoconfiguration
1666 [ISAPNP] Exclude DMAs for the autoconfiguration
1668 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1669 Ranges are in pairs (I/O port base and size).
1672 [ISAPNP] Exclude memory regions for the
1674 Ranges are in pairs (memory base and size).
1676 print-fatal-signals=
1677 [KNL] debug: print fatal signals
1678 print-fatal-signals=1: print segfault info to
1682 printk.time= Show timing data prefixed to each printk message line
1683 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1685 profile= [KNL] Enable kernel profiling via /proc/profile
1686 Format: [schedule,]<number>
1687 Param: "schedule" - profile schedule points.
1688 Param: <number> - step/bucket size as a power of 2 for
1689 statistical time based profiling.
1690 Param: "sleep" - profile D-state sleeping (millisecs).
1691 Requires CONFIG_SCHEDSTATS
1692 Param: "kvm" - profile VM exits.
1694 processor.max_cstate= [HW,ACPI]
1695 Limit processor to maximum C-state
1696 max_cstate=9 overrides any DMI blacklist limit.
1698 processor.nocst [HW,ACPI]
1699 Ignore the _CST method to determine C-states,
1700 instead using the legacy FADT method
1702 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1704 See Documentation/ramdisk.txt.
1706 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1707 probe for; one of (bare|imps|exps|lifebook|any).
1708 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1710 psmouse.resetafter= [HW,MOUSE]
1711 Try to reset the device after so many bad packets
1714 [HW,MOUSE] Set desired mouse resolution, in dpi.
1715 psmouse.smartscroll=
1716 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1717 0 = disabled, 1 = enabled (default).
1719 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1721 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1724 See Documentation/paride.txt.
1727 [KNL] Number of legacy pty's. Overwrites compiled-in
1730 quiet [KNL] Disable most log messages
1735 See Documentation/md.txt.
1737 ramdisk_blocksize= [RAM]
1738 See Documentation/ramdisk.txt.
1740 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1741 See Documentation/ramdisk.txt.
1743 rcupdate.blimit= [KNL,BOOT]
1744 Set maximum number of finished RCU callbacks to process
1747 rcupdate.qhimark= [KNL,BOOT]
1748 Set threshold of queued
1749 RCU callbacks over which batch limiting is disabled.
1751 rcupdate.qlowmark= [KNL,BOOT]
1752 Set threshold of queued RCU callbacks below which
1753 batch limiting is re-enabled.
1757 Run specified binary instead of /init from the ramdisk,
1758 used for early userspace startup. See initrd.
1760 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1761 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1762 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1765 [KNL, SMP] Set scheduler's default relax_domain_level.
1766 See Documentation/cpusets.txt.
1768 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1770 reservetop= [X86-32]
1772 Reserves a hole at the top of the kernel virtual
1775 reset_devices [KNL] Force drivers to reset the underlying device
1776 during initialization.
1779 Specify the partition device for software suspend
1781 resume_offset= [SWSUSP]
1782 Specify the offset from the beginning of the partition
1783 given by "resume=" at which the swap header is located,
1784 in <PAGE_SIZE> units (needed only for swap files).
1785 See Documentation/power/swsusp-and-swap-files.txt
1787 retain_initrd [RAM] Keep initrd memory after extraction
1789 rhash_entries= [KNL,NET]
1790 Set number of hash buckets for route cache
1792 riscom8= [HW,SERIAL]
1793 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1795 ro [KNL] Mount root device read-only on boot
1797 root= [KNL] Root filesystem
1799 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1800 mount the root filesystem
1802 rootflags= [KNL] Set root filesystem mount option string
1804 rootfstype= [KNL] Set root filesystem type
1806 rootwait [KNL] Wait (indefinitely) for root device to show up.
1807 Useful for devices that are detected asynchronously
1808 (e.g. USB and MMC devices).
1810 root_plug.vendor_id=
1811 [ROOTPLUG] Override the default vendor ID
1813 root_plug.product_id=
1814 [ROOTPLUG] Override the default product ID
1817 [ROOTPLUG] Enable debugging output
1819 rw [KNL] Mount root device read-write on boot
1821 S [KNL] Run init in single mode
1824 See drivers/net/irda/sa1100_ir.c.
1826 sbni= [NET] Granch SBNI12 leased line adapter
1828 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1829 Format: <io>[,<timeout>[,<isapnp>]]
1831 scsi_debug_*= [SCSI]
1832 See drivers/scsi/scsi_debug.c.
1834 scsi_default_dev_flags=
1835 [SCSI] SCSI default device flags
1838 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1839 Format: <vendor>:<model>:<flags>
1840 (flags are integer value)
1842 scsi_logging_level= [SCSI] a bit mask of logging levels
1843 See drivers/scsi/scsi_logging.h for bits. Also
1844 settable via sysctl at dev.scsi.logging_level
1845 (/proc/sys/dev/scsi/logging_level).
1846 There is also a nice 'scsi_logging_level' script in the
1847 S390-tools package, available for download at
1848 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1850 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1851 discovered. async scans them in kernel threads,
1852 allowing boot to proceed. none ignores them, expecting
1853 user space to do the scan.
1855 selinux [SELINUX] Disable or enable SELinux at boot time.
1856 Format: { "0" | "1" }
1857 See security/selinux/Kconfig help text.
1860 Default value is set via kernel config option.
1861 If enabled at boot time, /selinux/disable can be used
1862 later to disable prior to initial policy load.
1864 selinux_compat_net =
1865 [SELINUX] Set initial selinux_compat_net flag value.
1866 Format: { "0" | "1" }
1867 0 -- use new secmark-based packet controls
1868 1 -- use legacy packet controls
1869 Default value is 0 (preferred).
1870 Value can be changed at runtime via
1871 /selinux/compat_net.
1873 serialnumber [BUGS=X86-32]
1876 Maximal number of shapers.
1879 See header of drivers/scsi/sim710.c.
1886 slub_debug[=options[,slabs]] [MM, SLUB]
1887 Enabling slub_debug allows one to determine the
1888 culprit if slab objects become corrupted. Enabling
1889 slub_debug can create guard zones around objects and
1890 may poison objects when not in use. Also tracks the
1891 last alloc / free. For more information see
1892 Documentation/vm/slub.txt.
1894 slub_max_order= [MM, SLUB]
1895 Determines the maximum allowed order for slabs.
1896 A high setting may cause OOMs due to memory
1897 fragmentation. For more information see
1898 Documentation/vm/slub.txt.
1900 slub_min_objects= [MM, SLUB]
1901 The minimum number of objects per slab. SLUB will
1902 increase the slab order up to slub_max_order to
1903 generate a sufficiently large slab able to contain
1904 the number of objects indicated. The higher the number
1905 of objects the smaller the overhead of tracking slabs
1906 and the less frequently locks need to be acquired.
1907 For more information see Documentation/vm/slub.txt.
1909 slub_min_order= [MM, SLUB]
1910 Determines the mininum page order for slabs. Must be
1911 lower than slub_max_order.
1912 For more information see Documentation/vm/slub.txt.
1914 slub_nomerge [MM, SLUB]
1915 Disable merging of slabs with similar size. May be
1916 necessary if there is some reason to distinguish
1917 allocs to different slabs. Debug options disable
1918 merging on their own.
1919 For more information see Documentation/vm/slub.txt.
1922 Format: <io1>[,<io2>[,...,<io8>]]
1924 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1925 attempt to substitute SMP alternatives once at boot.
1927 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1928 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1929 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1930 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1931 smsc-ircc2.ircc_irq= [HW] IRQ line
1932 smsc-ircc2.ircc_dma= [HW] DMA channel
1933 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1934 0: Toshiba Satellite 1800 (GP data pin select)
1935 1: Fast pin select (default)
1938 snd-ad1816a= [HW,ALSA]
1940 snd-ad1848= [HW,ALSA]
1942 snd-ali5451= [HW,ALSA]
1944 snd-als100= [HW,ALSA]
1946 snd-als4000= [HW,ALSA]
1948 snd-azt2320= [HW,ALSA]
1950 snd-cmi8330= [HW,ALSA]
1952 snd-cmipci= [HW,ALSA]
1954 snd-cs4231= [HW,ALSA]
1956 snd-cs4232= [HW,ALSA]
1958 snd-cs4236= [HW,ALSA]
1960 snd-cs4281= [HW,ALSA]
1962 snd-cs46xx= [HW,ALSA]
1964 snd-dt019x= [HW,ALSA]
1966 snd-dummy= [HW,ALSA]
1968 snd-emu10k1= [HW,ALSA]
1970 snd-ens1370= [HW,ALSA]
1972 snd-ens1371= [HW,ALSA]
1974 snd-es968= [HW,ALSA]
1976 snd-es1688= [HW,ALSA]
1978 snd-es18xx= [HW,ALSA]
1980 snd-es1938= [HW,ALSA]
1982 snd-es1968= [HW,ALSA]
1984 snd-fm801= [HW,ALSA]
1986 snd-gusclassic= [HW,ALSA]
1988 snd-gusextreme= [HW,ALSA]
1990 snd-gusmax= [HW,ALSA]
1994 snd-ice1712= [HW,ALSA]
1996 snd-intel8x0= [HW,ALSA]
1998 snd-interwave= [HW,ALSA]
2003 snd-korg1212= [HW,ALSA]
2005 snd-maestro3= [HW,ALSA]
2007 snd-mpu401= [HW,ALSA]
2009 snd-mtpav= [HW,ALSA]
2011 snd-nm256= [HW,ALSA]
2013 snd-opl3sa2= [HW,ALSA]
2021 snd-opti93x= [HW,ALSA]
2025 snd-rme32= [HW,ALSA]
2027 snd-rme96= [HW,ALSA]
2029 snd-rme9652= [HW,ALSA]
2035 snd-sbawe= [HW,ALSA]
2037 snd-serial= [HW,ALSA]
2039 snd-sgalaxy= [HW,ALSA]
2041 snd-sonicvibes= [HW,ALSA]
2046 snd-sun-cs4231= [HW,ALSA]
2048 snd-trident= [HW,ALSA]
2050 snd-usb-audio= [HW,ALSA,USB]
2052 snd-via82xx= [HW,ALSA]
2054 snd-virmidi= [HW,ALSA]
2056 snd-wavefront= [HW,ALSA]
2058 snd-ymfpci= [HW,ALSA]
2061 [KNL] Should the soft-lockup detector generate panics.
2063 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2064 See Documentation/sonypi.txt
2066 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2067 See Documentation/specialix.txt.
2069 spia_io_base= [HW,MTD]
2075 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2077 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2078 See Documentation/scsi/st.txt.
2082 Set the STI (builtin display/keyboard on the HP-PARISC
2083 machines) console (graphic card) which should be used
2084 as the initial boot-console.
2085 See also comment in drivers/video/console/sticore.c.
2088 See comment in drivers/video/console/sticore.c.
2091 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2095 Control how the NFS server code allocates CPUs to
2096 service thread pools. Depending on how many NICs
2097 you have and where their interrupts are bound, this
2098 option will affect which CPUs will do NFS serving.
2099 Note: this parameter cannot be changed while the
2100 NFS server is running.
2102 auto the server chooses an appropriate mode
2103 automatically using heuristics
2104 global a single global pool contains all CPUs
2105 percpu one pool for each CPU
2106 pernode one pool for each NUMA node (equivalent
2107 to global on non-NUMA machines)
2109 swiotlb= [IA-64] Number of I/O TLB slabs
2113 sym53c416= [HW,SCSI]
2114 See header of drivers/scsi/sym53c416.c.
2116 sysrq_always_enabled
2118 Ignore sysrq setting - this boot parameter will
2119 neutralize any effect of /proc/sys/kernel/sysrq.
2120 Useful for debugging.
2123 See header of drivers/scsi/t128.c.
2127 test_suspend= [SUSPEND]
2128 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2129 standby suspend) as the system sleep state to briefly
2130 enter during system startup. The system is woken from
2131 this state using a wakeup-capable RTC alarm.
2133 thash_entries= [KNL,NET]
2134 Set number of hash buckets for TCP connection
2136 thermal.act= [HW,ACPI]
2137 -1: disable all active trip points in all thermal zones
2138 <degrees C>: override all lowest active trip points
2140 thermal.crt= [HW,ACPI]
2141 -1: disable all critical trip points in all thermal zones
2142 <degrees C>: lower all critical trip points
2144 thermal.nocrt= [HW,ACPI]
2145 Set to disable actions on ACPI thermal zone
2146 critical and hot trip points.
2148 thermal.off= [HW,ACPI]
2149 1: disable ACPI thermal control
2151 thermal.psv= [HW,ACPI]
2152 -1: disable all passive trip points
2153 <degrees C>: override all passive trip points to this value
2155 thermal.tzp= [HW,ACPI]
2156 Specify global default ACPI thermal zone polling rate
2157 <deci-seconds>: poll all this frequency
2158 0: no polling (default)
2160 tipar.timeout= [HW,PPT]
2161 Set communications timeout in tenths of a second
2164 tipar.delay= [HW,PPT]
2165 Set inter-bit delay in microseconds (default 10).
2168 See comment before function dc390_setup() in
2169 drivers/scsi/tmscsim.c.
2173 trix= [HW,OSS] MediaTrix AudioTrix Pro
2175 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2177 turbografx.map[2|3]= [HW,JOY]
2178 TurboGraFX parallel port interface
2180 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2181 See also Documentation/input/joystick-parport.txt
2183 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2184 See header of drivers/scsi/u14-34f.c.
2193 [USB] Ignore overcurrent events (default N).
2194 Some badly-designed motherboards generate lots of
2195 bogus events, for ports that aren't wired to
2196 anything. Set this parameter to avoid log spamming.
2197 Note that genuine overcurrent events won't be
2202 Set unknown_nmi_panic=1 early on boot.
2204 usbcore.autosuspend=
2205 [USB] The autosuspend time delay (in seconds) used
2206 for newly-detected USB devices (default 2). This
2207 is the time required before an idle device will be
2208 autosuspended. Devices for which the delay is set
2209 to a negative value won't be autosuspended at all.
2212 [USBHID] The interval which mice are to be polled at.
2214 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2215 kernel's map of available physical RAM.
2217 vdso= [X86-32,SH,x86-64]
2218 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2219 vdso=1: enable VDSO (default)
2220 vdso=0: disable VDSO mapping
2222 vdso32= [X86-32,X86-64]
2223 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2224 vdso32=1: enable 32-bit VDSO (default)
2225 vdso32=0: disable 32-bit VDSO mapping
2228 vector=percpu: enable percpu vector domain
2230 video= [FB] Frame buffer configuration
2231 See Documentation/fb/modedb.txt.
2233 vga= [BOOT,X86-32] Select a particular video mode
2234 See Documentation/i386/boot.txt and
2235 Documentation/svga.txt.
2236 Use vga=ask for menu.
2237 This is actually a boot loader parameter; the value is
2238 passed to the kernel using a special protocol.
2240 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2241 size of <nn>. This can be used to increase the
2242 minimum size (128MB on x86). It can also be used to
2243 decrease the size and leave more room for directly
2246 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2249 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2252 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2255 waveartist= [HW,OSS]
2256 Format: <io>,<irq>,<dma>,<dma2>
2259 See header of drivers/scsi/wd33c93.c.
2262 See header of drivers/scsi/wd7000.c.
2265 See Documentation/watchdog/wdt.txt.
2267 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2268 xd_geo= See header of drivers/block/xd.c.
2270 xirc2ps_cs= [NET,PCMCIA]
2272 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2274 norandmaps Don't use address space randomization
2275 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2277 ______________________________________________________________________
2281 Add documentation for ALSA options.
2282 Add more DRM drivers.