4 The following is a consolidated list of the kernel parameters as implemented
5 (mostly) by the __setup() macro and sorted into English Dictionary order
6 (defined as ignoring all punctuation and sorting digits before letters in a
7 case insensitive manner), and with descriptions where known.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
14 Module parameters for modules that are built into the kernel image
15 are specified on the kernel command line with the module name plus
16 '.' plus parameter name, with '=' and value if appropriate, such as:
18 usbcore.blinkenlights=1
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LIBATA Libata driver is enabled
53 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
61 MSI Message Signaled Interrupts (PCI).
62 MTD MTD (Memory Technology Device) support is enabled.
63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
65 GENERIC_TIME The generic timeofday code is enabled.
66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
72 PCIE PCI Express support is enabled.
73 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
79 ROOTPLUG The example Root Plug LSM is enabled.
80 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
84 SECURITY Different security models are enabled.
85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
87 SH SuperH architecture is enabled.
88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
90 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
92 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
100 X86-32 X86-32, aka i386 architecture is enabled.
101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
105 In addition, the following text indicates that the option:
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
111 Parameters denoted with BOOT are actually interpreted by the boot
112 loader, and have no meaning to the kernel directly.
113 Do not modify the syntax of boot loader parameters without extreme
114 need or coordination with <Documentation/i386/boot.txt>.
116 There are also arch-specific kernel-parameters not documented here.
117 See for example <Documentation/x86_64/boot-options.txt>.
119 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120 a trailing = on the name of any parameter states that that parameter will
121 be entered as an environment variable, whereas its absence indicates that
122 it will appear as a kernel argument readable via /proc/cmdline by programs
123 running once the system is up.
125 The number of kernel parameters is not limited, but the length of the
126 complete command line (parameters including spaces etc.) is limited to
127 a fixed number of characters. This limit depends on the architecture
128 and is between 256 and 4096 characters. It is defined in the file
129 ./include/asm/setup.h as COMMAND_LINE_SIZE.
132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
134 Format: { force | off | ht | strict | noirq }
135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
139 strict -- Be less tolerant of platforms that are not
140 strictly ACPI specification compliant.
142 See also Documentation/power/pm.txt, pci=noacpi
144 acpi_apic_instance= [ACPI, IOAPIC]
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
150 acpi_sleep= [HW,ACPI] Sleep options
151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
163 Format: { level | edge | high | low }
165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 Format: <irq>,<irq>...
177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
178 Format: <irq>,<irq>...
180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
190 acpi_serialize [HW,ACPI] force serialization of AML methods
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
200 acpi.debug_layer= [HW,ACPI]
202 Each bit of the <int> indicates an ACPI debug layer,
203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
217 acpi.debug_level= [HW,ACPI]
219 Each bit of the <int> indicates an ACPI debug level,
220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
235 acpi_pm_good [X86-32,X86-64]
236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
250 The kernel tries to set a reasonable default.
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
260 See header of drivers/scsi/advansys.c.
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
270 See Documentation/scsi/aha152x.txt.
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
276 See Documentation/scsi/aic7xxx.txt.
279 See Documentation/scsi/aic79xx.txt.
281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
287 fullflush - enable flushing of IO/TLB entries when
288 they are unmapped. Otherwise they are
289 flushed before they will be reused, which
292 amd_iommu_size= [HW,X86-64]
293 Define the size of the aperture for the AMD IOMMU
294 driver. Possible values are:
295 '32M', '64M' (default), '128M', '256M', '512M', '1G'
297 amijoy.map= [HW,JOY] Amiga joystick support
298 Map of devices attached to JOY0DAT and JOY1DAT
300 See also Documentation/kernel/input/joystick.txt
302 analog.map= [HW,JOY] Analog joystick and gamepad support
303 Specifies type or capabilities of an analog joystick
304 connected to one of 16 gameports
305 Format: <type1>,<type2>,..<type16>
308 Power management functions (SPARCstation-4/5 + deriv.)
310 Disable APC CPU standby support. SPARCstation-Fox does
311 not play well with APC CPU idle - disable it if you have
312 APC and your system crashes randomly.
314 apic= [APIC,i386] Advanced Programmable Interrupt Controller
315 Change the output verbosity whilst booting
316 Format: { quiet (default) | verbose | debug }
317 Change the amount of debugging information output
318 when initialising the APIC and IO-APIC components.
320 apm= [APM] Advanced Power Management
321 See header of arch/x86/kernel/apm_32.c.
323 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
324 Format: <io>,<irq>,<nodeID>
328 atarimouse= [HW,MOUSE] Atari Mouse
330 atascsi= [HW,SCSI] Atari SCSI
332 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
333 EzKey and similar keyboards
335 atkbd.reset= [HW] Reset keyboard during initialization
337 atkbd.set= [HW] Select keyboard code set
338 Format: <int> (2 = AT (default), 3 = PS/2)
340 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
343 atkbd.softraw= [HW] Choose between synthetic and real raw mode
344 Format: <bool> (0 = real, 1 = synthetic (default))
346 atkbd.softrepeat= [HW]
347 Use software keyboard repeat
351 baycom_epp= [HW,AX25]
354 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
356 See header of drivers/net/hamradio/baycom_par.c.
358 baycom_ser_fdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
360 Format: <io>,<irq>,<mode>[,<baud>]
361 See header of drivers/net/hamradio/baycom_ser_fdx.c.
363 baycom_ser_hdx= [HW,AX25]
364 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
365 Format: <io>,<irq>,<mode>
366 See header of drivers/net/hamradio/baycom_ser_hdx.c.
368 boot_delay= Milliseconds to delay each printk during boot.
369 Values larger than 10 seconds (10000) are changed to
373 bootmem_debug [KNL] Enable bootmem allocator debug messages.
375 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
376 bttv.radio= Most important insmod options are available as
378 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
379 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
382 See drivers/scsi/BusLogic.c, comment before function
383 BusLogic_ParseDriverOptions().
385 c101= [NET] Moxa C101 synchronous serial card
387 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
388 Sometimes CPU hardware bugs make them report the cache
389 size incorrectly. The kernel will attempt work arounds
390 to fix known problems, but for some CPUs it is not
391 possible to determine what the correct size should be.
392 This option provides an override for these situations.
394 security= [SECURITY] Choose a security module to enable at boot.
395 If this boot parameter is not specified, only the first
396 security module asking for security registration will be
397 loaded. An invalid security module name will be treated
398 as if no module has been chosen.
401 [SECURITY] Disable capabilities. This would normally
402 be used only if an alternative security model is to be
403 configured. Potentially dangerous and should only be
404 used if you are entirely sure of the consequences.
406 ccw_timeout_log [S390]
407 See Documentation/s390/CommonIO for details.
409 cgroup_disable= [KNL] Disable a particular controller
410 Format: {name of the controller(s) to disable}
411 {Currently supported controllers - "memory"}
413 checkreqprot [SELINUX] Set initial checkreqprot flag value.
414 Format: { "0" | "1" }
415 See security/selinux/Kconfig help text.
416 0 -- check protection applied by kernel (includes
417 any implied execute protection).
418 1 -- check protection requested by application.
419 Default value is set via a kernel config option.
420 Value can be changed at runtime via
421 /selinux/checkreqprot.
424 See Documentation/s390/CommonIO for details.
426 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
428 Forces specified clocksource (if available) to be used
429 when calculating gettimeofday(). If specified
430 clocksource is not available, it defaults to PIT.
431 Format: { pit | tsc | cyclone | pmtmr }
433 clocksource= [GENERIC_TIME] Override the default clocksource
435 Override the default clocksource and use the clocksource
436 with the name specified.
437 Some clocksource names to choose from, depending on
439 [all] jiffies (this is the base, fallback clocksource)
441 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
442 pxa_timer,timer3,32k_counter,timer0_1
444 [X86-32] pit,hpet,tsc,vmi-timer;
445 scx200_hrt on Geode; cyclone on IBM x440
453 clearcpuid=BITNUM [X86]
454 Disable CPUID feature X for the kernel. See
455 include/asm-x86/cpufeature.h for the valid bit numbers.
456 Note the Linux specific bits are not necessarily
457 stable over kernel options, but the vendor specific
459 Also note that user programs calling CPUID directly
460 or using the feature without checking anything
461 will still see it. This just prevents it from
462 being used by the kernel or shown in /proc/cpuinfo.
463 Also note the kernel might malfunction if you disable
466 code_bytes [IA32/X86_64] How many bytes of object code to print
471 hpet= [X86-32,HPET] option to control HPET usage
472 Format: { enable (default) | disable | force }
473 disable: disable HPET and use PIT instead
474 force: allow force enabled of undocumented chips (ICH4,
477 com20020= [HW,NET] ARCnet - COM20020 chipset
479 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
481 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
485 ARCnet - COM90xx chipset (memory-mapped buffers)
486 Format: <io>[,<irq>[,<memstart>]]
488 condev= [HW,S390] console device
491 console= [KNL] Output console device and options.
493 tty<n> Use the virtual console device <n>.
497 Use the specified serial port. The options are of
498 the form "bbbbpnf", where "bbbb" is the baud rate,
499 "p" is parity ("n", "o", or "e"), "n" is number of
500 bits, and "f" is flow control ("r" for RTS or
501 omit it). Default is "9600n8".
503 See Documentation/serial-console.txt for more
505 Documentation/networking/netconsole.txt for an
508 uart[8250],io,<addr>[,options]
509 uart[8250],mmio,<addr>[,options]
510 Start an early, polled-mode console on the 8250/16550
511 UART at the specified I/O port or MMIO address,
512 switching to the matching ttyS device later. The
513 options are the same as for ttyS, above.
515 If the device connected to the port is not a TTY but a braille
516 device, prepend "brl," before the device type, for instance
518 For now, only VisioBraille is supported.
520 earlycon= [KNL] Output early console device and options.
521 uart[8250],io,<addr>[,options]
522 uart[8250],mmio,<addr>[,options]
523 Start an early, polled-mode console on the 8250/16550
524 UART at the specified I/O port or MMIO address.
525 The options are the same as for ttyS, above.
528 [HW] Never suspend the console
529 Disable suspending of consoles during suspend and
530 hibernate operations. Once disabled, debugging
531 messages can reach various consoles while the rest
532 of the system is being put to sleep (ie, while
533 debugging driver suspend/resume hooks). This may
534 not work reliably with all consoles, but is known
535 to work with serial and VGA consoles.
537 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
539 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
541 crashkernel=nn[KMG]@ss[KMG]
542 [KNL] Reserve a chunk of physical memory to
543 hold a kernel to switch to with kexec on panic.
545 crashkernel=range1:size1[,range2:size2,...][@offset]
546 [KNL] Same as above, but depends on the memory
547 in the running system. The syntax of range is
548 start-[end] where start and end are both
549 a memory unit (amount[KMG]). See also
550 Documentation/kdump/kdump.txt for a example.
553 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
558 cs89x0_media= [HW,NET]
559 Format: { rj45 | aui | bnc }
562 See header of drivers/s390/block/dasd_devmap.c.
564 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
565 (one device per port)
566 Format: <port#>,<type>
567 See also Documentation/input/joystick-parport.txt
569 debug [KNL] Enable kernel debugging (events log level).
572 [KNL] verbose self-tests
574 Print debugging info while doing the locking API
576 We default to 0 (no extra messages), setting it to
577 1 will print _a lot_ more information - normally
578 only useful to kernel developers.
580 debug_objects [KNL] Enable object debugging
582 debugpat [X86] Enable PAT debugging
584 decnet.addr= [HW,NET]
585 Format: <area>[,<node>]
586 See also Documentation/networking/decnet.txt.
589 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
590 Change the default blue palette of the console.
591 This is a 16-member array composed of values
595 Format: <green0>,<green1>,<green2>,...,<green15>
596 Change the default green palette of the console.
597 This is a 16-member array composed of values
601 Format: <red0>,<red1>,<red2>,...,<red15>
602 Change the default red palette of the console.
603 This is a 16-member array composed of values
609 Set system-wide default UTF-8 mode for all tty's.
610 Default is 1, i.e. UTF-8 mode is enabled for all
611 newly opened terminals.
614 Set number of hash buckets for dentry cache.
617 IO parameters + enable/disable command.
619 digiepca= [HW,SERIAL]
620 See drivers/char/README.epca and
621 Documentation/digiepca.txt.
623 disable_mtrr_cleanup [X86]
624 enable_mtrr_cleanup [X86]
625 The kernel tries to adjust MTRR layout from continuous
626 to discrete, to make X server driver able to add WB
627 entry later. This parameter enables/disables that.
629 mtrr_chunk_size=nn[KMG] [X86]
630 used for mtrr cleanup. It is largest continous chunk
631 that could hold holes aka. UC entries.
633 mtrr_gran_size=nn[KMG] [X86]
634 Used for mtrr cleanup. It is granularity of mtrr block.
636 Large value could prevent small alignment from
639 mtrr_spare_reg_nr=n [X86]
641 Range: 0,7 : spare reg number
643 Used for mtrr cleanup. It is spare mtrr entries number.
644 Set to 2 or more if your graphical card needs more.
646 disable_mtrr_trim [X86, Intel and AMD only]
647 By default the kernel will trim any uncacheable
648 memory out of your available memory pool based on
649 MTRR settings. This parameter disables that behavior,
650 possibly causing your machine to run very slowly.
652 dmasound= [HW,OSS] Sound subsystem buffers
658 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
660 earlyprintk=serial[,ttySn[,baudrate]]
662 Append ",keep" to not disable it when the real console
665 Only vga or serial at a time, not both.
667 Currently only ttyS0 and ttyS1 are supported.
669 Interaction with the standard serial driver is not
672 The VGA output is eventually overwritten by the real
678 Format: {"off" | "on" | "skip[mbr]"}
680 eisa_irq_edge= [PARISC,HW]
681 See header of drivers/parisc/eisa.c.
684 See comment before function elanfreq_setup() in
685 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
688 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
689 See Documentation/block/as-iosched.txt and
690 Documentation/block/deadline-iosched.txt for details.
692 elfcorehdr= [X86-32, X86_64]
693 Specifies physical address of start of kernel core
694 image elf header. Generally kexec loader will
695 pass this option to capture kernel.
696 See Documentation/kdump/kdump.txt for details.
698 enforcing [SELINUX] Set initial enforcing status.
700 See security/selinux/Kconfig help text.
701 0 -- permissive (log only, no denials).
702 1 -- enforcing (deny and log).
704 Value can be changed at runtime via /selinux/enforce.
707 Format: <spdif>,[<nomix>,[<amplifier>]]
708 See also header of sound/oss/es1371.c.
710 ether= [HW,NET] Ethernet cards parameters
711 This option is obsoleted by the "netdev=" option, which
712 has equivalent usage. See its documentation for details.
714 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
719 fail_make_request=[KNL]
720 General fault injection mechanism.
721 Format: <interval>,<probability>,<space>,<times>
722 See also /Documentation/fault-injection/.
725 See header of drivers/scsi/fd_mcs.c.
728 See header of drivers/scsi/fdomain.c.
731 See Documentation/floppy.txt.
733 force_pal_cache_flush
734 [IA-64] Avoid check_sal_cache_flush which may hang on
735 buggy SAL_CACHE_FLUSH implementations. Using this
736 parameter will force ia64_sal_cache_flush to call
737 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
740 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
741 support via parallel port (up to 5 devices per port)
742 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
743 See also Documentation/input/joystick-parport.txt
747 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
752 See header of drivers/scsi/gdth.c.
754 gpt [EFI] Forces disk with valid GPT signature but
755 invalid Protective MBR to be treated as GPT.
759 hashdist= [KNL,NUMA] Large hashes allocated during boot
760 are distributed across NUMA nodes. Defaults on
761 for IA-64, off otherwise.
762 Format: 0 | 1 (for off | on)
764 hcl= [IA-64] SGI's Hardware Graph compatibility layer
766 hd= [EIDE] (E)IDE hard drive subsystem geometry
767 Format: <cyl>,<head>,<sect>
769 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
770 size of <nn>. This works even on boxes that have no
771 highmem otherwise. This also works to reduce highmem
772 size on bigger boxes.
774 highres= [KNL] Enable/disable high resolution timer mode.
775 Valid parameters: "on", "off"
779 See Documentation/isdn/README.HiSax.
781 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
782 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
783 On x86-64 and powerpc, this option can be specified
784 multiple times interleaved with hugepages= to reserve
785 huge pages of different sizes. Valid pages sizes on
786 x86-64 are 2M (when the CPU supports "pse") and 1G
787 (when the CPU supports the "pdpe1gb" cpuinfo flag)
788 Note that 1GB pages can only be allocated at boot time
789 using hugepages= and not freed afterwards.
791 [same as hugepagesz=] The size of the default
792 HugeTLB page size. This is the size represented by
793 the legacy /proc/ hugepages APIs, used for SHM, and
794 default size when mounting hugetlbfs filesystems.
795 Defaults to the default architecture's huge page size
798 i8042.direct [HW] Put keyboard port into non-translated mode
799 i8042.dumbkbd [HW] Pretend that controller can only read data from
800 keyboard and cannot control its state
801 (Don't attempt to blink the leds)
802 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
803 i8042.nokbd [HW] Don't check/create keyboard port
804 i8042.noloop [HW] Disable the AUX Loopback command while probing
806 i8042.nomux [HW] Don't check presence of an active multiplexing
808 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
811 [HW] Frequency with which keyboard LEDs should blink
812 when kernel panics (default is 0.5 sec)
813 i8042.reset [HW] Reset the controller during init and cleanup
814 i8042.unlock [HW] Unlock (ignore) the keylock
818 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
819 indicates that the driver is running on unsupported
821 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
822 does not match list of supported models.
824 [HW] Report power status in /proc/i8k
825 (disabled by default)
826 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
829 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
830 See Documentation/mca.txt.
833 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
835 ide= [HW] (E)IDE subsystem
836 Format: ide=nodma or ide=doubler
837 See Documentation/ide/ide.txt.
839 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
840 See Documentation/ide/ide.txt.
843 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
844 Poll forces a polling idle loop that can slightly improves the performance
845 of waking up a idle CPU, but will use a lot of power and make the system
846 run hot. Not recommended.
847 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
848 to not use it because it doesn't save as much power as a normal idle
849 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
851 idle=halt. Halt is forced to be used for CPU idle.
852 In such case C2/C3 won't be used again.
853 idle=nomwait. Disable mwait for CPU C-states
855 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
856 Claim all unknown PCI IDE storage controllers.
858 ignore_loglevel [KNL]
859 Ignore loglevel setting - this will print /all/
860 kernel messages to the console. Useful for debugging.
863 Set number of hash buckets for inode cache.
866 See header of drivers/scsi/in2000.c.
870 Run specified binary instead of /sbin/init as init
873 initcall_debug [KNL] Trace initcalls as they are executed. Useful
874 for working out where the kernel is dying during
877 initrd= [BOOT] Specify the location of the initial ramdisk
879 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
897 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
899 Disable intel iommu driver.
900 igfx_off [Default Off]
901 By default, gfx is mapped as normal device. If a gfx
902 device has a dedicated DMAR unit, the DMAR unit is
903 bypassed by not enabling DMAR with this option. In
904 this case, gfx device will use physical address for
907 With this option iommu will not optimize to look
908 for io virtual address below 32 bit forcing dual
909 address cycle on pci bus for cards supporting greater
910 than 32 bit addressing. The default is to look
911 for translation below 32 bit and if not available
912 then look in the higher range.
914 With this option on every unmap_single operation will
915 result in a hardware IOTLB flush operation as opposed
916 to batching them for performance.
918 io_delay= [X86-32,X86-64] I/O delay method
920 Standard port 0x80 based delay
922 Alternate port 0xed based delay (needed on some systems)
924 Simple two microseconds delay
928 io7= [HW] IO7 for Marvel based alpha systems
929 See comment before marvel_specify_io7 in
930 arch/alpha/kernel/core_marvel.c.
933 See Documentation/filesystems/nfsroot.txt.
935 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
936 See comment before ip2_setup() in
937 drivers/char/ip2/ip2base.c.
939 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
940 See header of drivers/scsi/ips.c.
942 ports= [IP_VS_FTP] IPVS ftp helper module
944 Up to 8 (IP_VS_APP_MAX_PORTS) ports
946 Format: <port>,<port>....
949 When an interrupt is not handled search all handlers
950 for it. Intended to get systems with badly broken
954 When an interrupt is not handled search all handlers
955 for it. Also check all handlers each timer
956 interrupt. Intended to get systems with badly broken
960 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
962 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
964 <cpu number>,...,<cpu number>
966 <cpu number>-<cpu number> (must be a positive range in ascending order)
968 <cpu number>,...,<cpu number>-<cpu number>
969 This option can be used to specify one or more CPUs
970 to isolate from the general SMP balancing and scheduling
971 algorithms. The only way to move a process onto or off
972 an "isolated" CPU is via the CPU affinity syscalls.
973 <cpu number> begins at 0 and the maximum value is
974 "number of CPUs in system - 1".
976 This option is the preferred way to isolate CPUs. The
977 alternative -- manually setting the CPU mask of all
978 tasks in the system -- can cause problems and
979 suboptimal load balancer performance.
983 js= [HW,JOY] Analog joystick
984 See Documentation/input/joystick.txt.
986 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
987 specifies the amount of memory usable by the kernel
988 for non-movable allocations. The requested amount is
989 spread evenly throughout all nodes in the system. The
990 remaining memory in each node is used for Movable
991 pages. In the event, a node is too small to have both
992 kernelcore and Movable pages, kernelcore pages will
993 take priority and other nodes will have a larger number
994 of kernelcore pages. The Movable zone is used for the
995 allocation of pages that may be reclaimed or moved
996 by the page migration subsystem. This means that
997 HugeTLB pages may not be allocated from this zone.
998 Note that allocations like PTEs-from-HighMem still
999 use the HighMem zone if it exists, and the Normal
1000 zone if it does not.
1002 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1003 is similar to kernelcore except it specifies the
1004 amount of memory used for migratable allocations.
1005 If both kernelcore and movablecore is specified,
1006 then kernelcore will be at *least* the specified
1007 value but may be more. If movablecore on its own
1008 is specified, the administrator must be careful
1009 that the amount of memory usable for all allocations
1014 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1017 kgdboc= [HW] kgdb over consoles.
1018 Requires a tty driver that supports console polling.
1019 (only serial suported for now)
1020 Format: <serial_device>[,baud]
1026 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1029 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1032 libata.dma= [LIBATA] DMA control
1033 libata.dma=0 Disable all PATA and SATA DMA
1034 libata.dma=1 PATA and SATA Disk DMA only
1035 libata.dma=2 ATAPI (CDROM) DMA only
1036 libata.dma=4 Compact Flash DMA only
1037 Combinations also work, so libata.dma=3 enables DMA
1038 for disks and CDROMs, but not CFs.
1040 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1044 libata.force= [LIBATA] Force configurations. The format is comma
1045 separated list of "[ID:]VAL" where ID is
1046 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1047 matching port, link or device. Basically, it matches
1048 the ATA ID string printed on console by libata. If
1049 the whole ID part is omitted, the last PORT and DEVICE
1050 values are used. If ID hasn't been specified yet, the
1051 configuration applies to all ports, links and devices.
1053 If only DEVICE is omitted, the parameter applies to
1054 the port and all links and devices behind it. DEVICE
1055 number of 0 either selects the first device or the
1056 first fan-out link behind PMP device. It does not
1057 select the host link. DEVICE number of 15 selects the
1058 host link and device attached to it.
1060 The VAL specifies the configuration to force. As long
1061 as there's no ambiguity shortcut notation is allowed.
1062 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1063 The following configurations can be forced.
1065 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1066 Any ID with matching PORT is used.
1068 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1070 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1071 udma[/][16,25,33,44,66,100,133] notation is also
1074 * [no]ncq: Turn on or off NCQ.
1076 * nohrst, nosrst, norst: suppress hard, soft
1079 If there are multiple matching configurations changing
1080 the same attribute, the last one is used.
1082 load_ramdisk= [RAM] List of ramdisks to load from floppy
1083 See Documentation/ramdisk.txt.
1085 lockd.nlm_grace_period=P [NFS] Assign grace period.
1088 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1091 lockd.nlm_timeout=T [NFS] Assign timeout value.
1094 lockd.nlm_udpport=M [NFS] Assign UDP port.
1097 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1100 loglevel= All Kernel Messages with a loglevel smaller than the
1101 console loglevel will be printed to the console. It can
1102 also be changed with klogd or other programs. The
1103 loglevels are defined as follows:
1105 0 (KERN_EMERG) system is unusable
1106 1 (KERN_ALERT) action must be taken immediately
1107 2 (KERN_CRIT) critical conditions
1108 3 (KERN_ERR) error conditions
1109 4 (KERN_WARNING) warning conditions
1110 5 (KERN_NOTICE) normal but significant condition
1111 6 (KERN_INFO) informational
1112 7 (KERN_DEBUG) debug-level messages
1114 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1115 Format: { n | nk | nM }
1116 n must be a power of two. The default size
1117 is set in the kernel config file.
1119 logo.nologo [FB] Disables display of the built-in Linux logo.
1120 This may be used to provide more screen space for
1121 kernel log messages and is useful when debugging
1122 kernel boot problems.
1124 lp=0 [LP] Specify parallel ports to use, e.g,
1125 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1126 lp=reset first parallel port). 'lp=0' disables the
1127 lp=auto printer driver. 'lp=reset' (which can be
1128 specified in addition to the ports) causes
1129 attached printers to be reset. Using
1130 lp=port1,port2,... specifies the parallel ports
1131 to associate lp devices with, starting with
1132 lp0. A port specification may be 'none' to skip
1133 that lp device, or a parport name such as
1134 'parport0'. Specifying 'lp=auto' instead of a
1135 port specification list means that device IDs
1136 from each port should be examined, to see if
1137 an IEEE 1284-compliant printer is attached; if
1138 so, the driver will manage that printer.
1139 See also header of drivers/char/lp.c.
1142 Sets loops_per_jiffy to given constant, thus avoiding
1143 time-consuming boot-time autodetection (up to 250 ms per
1144 CPU). 0 enables autodetection (default). To determine
1145 the correct value for your kernel, boot with normal
1146 autodetection and see what value is printed. Note that
1147 on SMP systems the preset will be applied to all CPUs,
1148 which is likely to cause problems if your CPUs need
1149 significantly divergent settings. An incorrect value
1150 will cause delays in the kernel to be wrong, leading to
1151 unpredictable I/O errors and other breakage. Although
1152 unlikely, in the extreme case this might damage your
1156 Format: <io>,<irq>,<dma>
1158 mac5380= [HW,SCSI] Format:
1159 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1161 machvec= [IA64] Force the use of a particular machine-vector
1162 (machvec) in a generic kernel.
1163 Example: machvec=hpzx1_swiotlb
1165 max_loop= [LOOP] Maximum number of loopback devices that can
1169 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1170 should make use of. maxcpus=n : n >= 0 limits the
1171 kernel to using 'n' processors. n=0 is a special case,
1172 it is equivalent to "nosmp", which also disables
1175 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1176 equal to this physical address is ignored.
1178 max_luns= [SCSI] Maximum number of LUNs to probe.
1179 Should be between 1 and 2^32-1.
1182 [SCSI] Maximum number of LUNs received.
1183 Should be between 1 and 16384.
1187 mce [X86-32] Machine Check Exception
1189 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1191 md= [HW] RAID subsystems devices and level
1192 See Documentation/md.txt.
1195 Format: <first>,<last>
1196 Specifies range of consoles to be captured by the MDA.
1198 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1199 Amount of memory to be used when the kernel is not able
1200 to see the whole system memory or for test.
1201 [X86-32] Use together with memmap= to avoid physical
1202 address space collisions. Without memmap= PCI devices
1203 could be placed at addresses belonging to unused RAM.
1205 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1208 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1209 E820 memory map, as specified by the user.
1210 Such memmap=exactmap lines can be constructed based on
1211 BIOS output or other requirements. See the memmap=nn@ss
1214 memmap=nn[KMG]@ss[KMG]
1215 [KNL] Force usage of a specific region of memory
1216 Region of memory to be used, from ss to ss+nn.
1218 memmap=nn[KMG]#ss[KMG]
1219 [KNL,ACPI] Mark specific memory as ACPI data.
1220 Region of memory to be used, from ss to ss+nn.
1222 memmap=nn[KMG]$ss[KMG]
1223 [KNL,ACPI] Mark specific memory as reserved.
1224 Region of memory to be used, from ss to ss+nn.
1225 Example: Exclude memory from 0x18690000-0x1869ffff
1226 memmap=64K$0x18690000
1228 memmap=0x10000$0x18690000
1230 memtest= [KNL,X86] Enable memtest
1232 range: 0,4 : pattern number
1233 default : 0 <disable>
1235 meye.*= [HW] Set MotionEye Camera parameters
1236 See Documentation/video4linux/meye.txt.
1238 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1239 Multi-Function General Purpose Timers on AMD Geode
1242 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1243 the BIOS has incorrectly applied a workaround. TinyBIOS
1244 version 0.98 is known to be affected, 0.99 fixes the
1245 problem by letting the user disable the workaround.
1250 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1251 parameter allows control of the logging verbosity for
1252 the additional memory initialisation checks. A value
1253 of 0 disables mminit logging and a level of 4 will
1254 log everything. Information is printed at KERN_DEBUG
1255 so loglevel=8 may also need to be specified.
1258 [MOUSE] Maximum time between finger touching and
1259 leaving touchpad surface for touch to be considered
1260 a tap and be reported as a left button click (for
1261 touchpads working in absolute mode only).
1263 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1264 reporting absolute coordinates, such as tablets
1265 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1266 reporting absolute coordinates, such as tablets
1271 MTD_Partition= [MTD]
1272 Format: <name>,<region-number>,<size>,<offset>
1274 MTD_Region= [MTD] Format:
1275 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1278 See drivers/mtd/cmdlinepart.c.
1281 ARM/S3C2412 JIVE boot control
1283 See arch/arm/mach-s3c2412/mach-jive.c
1285 mtouchusb.raw_coordinates=
1286 [HW] Make the MicroTouch USB driver use raw coordinates
1287 ('y', default) or cooked coordinates ('n')
1289 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1292 See header of drivers/scsi/NCR_D700.c.
1296 ncr53c400= [HW,SCSI]
1298 ncr53c400a= [HW,SCSI]
1300 ncr53c406a= [HW,SCSI]
1302 ncr53c8xx= [HW,SCSI]
1304 netdev= [NET] Network devices parameters
1305 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1306 Note that mem_start is often overloaded to mean
1307 something different and driver-specific.
1308 This usage is only documented in each driver source
1312 [NETFILTER] Enable connection tracking flow accounting
1313 0 to disable accounting
1314 1 to enable accounting
1315 Default value depends on CONFIG_NF_CT_ACCT that is
1316 going to be removed in 2.6.29.
1319 See Documentation/filesystems/nfsroot.txt.
1321 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1322 See Documentation/filesystems/nfsroot.txt.
1324 nfs.callback_tcpport=
1325 [NFS] set the TCP port on which the NFSv4 callback
1326 channel should listen.
1328 nfs.idmap_cache_timeout=
1329 [NFS] set the maximum lifetime for idmapper cache
1333 [NFS] enable 64-bit inode numbers.
1334 If zero, the NFS client will fake up a 32-bit inode
1335 number for the readdir() and stat() syscalls instead
1336 of returning the full 64-bit number.
1337 The default is to return 64-bit inode numbers.
1339 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1340 when a NMI is triggered.
1341 Format: [state][,regs][,debounce][,die]
1343 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1345 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1346 emulation library even if a 387 maths coprocessor
1349 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1350 caches in the slab allocator. Saves per-node memory,
1351 but will impact performance.
1355 noapic [SMP,APIC] Tells the kernel to not make use of any
1356 IOAPICs that may be present in the system.
1358 nobats [PPC] Do not use BATs for mapping kernel lowmem
1359 on "Classic" PPC cores.
1363 nodelayacct [KNL] Disable per-task delay accounting
1365 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1367 noefi [X86-32,X86-64] Disable EFI runtime services support.
1371 noexec [X86-32,X86-64]
1372 On X86-32 available only on PAE configured kernels.
1373 noexec=on: enable non-executable mappings (default)
1374 noexec=off: disable non-executable mappings
1377 This affects only 32-bit executables.
1378 noexec32=on: enable non-executable mappings (default)
1379 read doesn't imply executable mappings
1380 noexec32=off: disable non-executable mappings
1381 read implies executable mappings
1383 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1384 register save and restore. The kernel will only save
1385 legacy floating-point registers on task switch.
1387 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1391 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1392 instruction doesn't work correctly and not to
1395 nohalt [IA-64] Tells the kernel not to use the power saving
1396 function PAL_HALT_LIGHT when idle. This increases
1397 power-consumption. On the positive side, it reduces
1398 interrupt wake-up latency, which may improve performance
1399 in certain environments such as networked servers or
1402 nohz= [KNL] Boottime enable/disable dynamic ticks
1403 Valid arguments: on, off
1406 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1408 noirqdebug [X86-32] Disables the code which attempts to detect and
1409 disable unhandled interrupt sources.
1411 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1412 broken timer IRQ sources.
1414 noisapnp [ISAPNP] Disables ISA PnP code.
1416 noinitrd [RAM] Tells the kernel not to load any configured
1421 nojitter [IA64] Disables jitter checking for ITC timers.
1423 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1425 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1427 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1429 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1430 default x2apic cluster mode on platforms
1433 noltlbs [PPC] Do not use large page/tlb entries for kernel
1434 lowmem mapping on PPC40x.
1436 nomca [IA-64] Disable machine check abort handling
1438 nomce [X86-32] Machine Check Exception
1440 nomfgpt [X86-32] Disable Multi-Function General Purpose
1441 Timer usage (for AMD Geode machines).
1443 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1445 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1446 with UP alternatives
1448 noresidual [PPC] Don't use residual data on PReP machines.
1450 noresume [SWSUSP] Disables resume and restores original swap
1453 no-scroll [VGA] Disables scrollback.
1454 This is required for the Braillex ib80-piezo Braille
1455 reader made by F.H. Papenmeier (Germany).
1459 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1461 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1462 and disable the IO APIC. legacy for "maxcpus=0".
1464 nosoftlockup [KNL] Disable the soft-lockup detector.
1466 nosync [HW,M68K] Disables sync negotiation for all devices.
1468 notsc [BUGS=X86-32] Disable Time Stamp Counter
1470 nousb [USB] Disable the USB subsystem
1474 nptcg= [IA64] Override max number of concurrent global TLB
1475 purges which is reported from either PAL_VM_SUMMARY or
1478 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1479 one of ['zone', 'node', 'default'] can be specified
1480 This can be set from sysctl after boot.
1481 See Documentation/sysctl/vm.txt for details.
1483 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1485 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1486 Rather than timing out after 20 ms if an EC
1487 command is not properly ACKed, override the length
1488 of the timeout. We have interrupts disabled while
1489 waiting for the ACK, so if this is set too high
1490 interrupts *may* be lost!
1495 oprofile.timer= [HW]
1496 Use timer interrupt instead of performance counters
1498 osst= [HW,SCSI] SCSI Tape Driver
1499 Format: <buffer_size>,<write_threshold>
1500 See also Documentation/scsi/st.txt.
1502 panic= [KNL] Kernel behaviour on panic
1505 parkbd.port= [HW] Parallel port number the keyboard adapter is
1506 connected to, default is 0.
1508 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1509 0 for XT, 1 for AT (default is AT).
1512 parport= [HW,PPT] Specify parallel ports. 0 disables.
1513 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1514 Use 'auto' to force the driver to use any
1515 IRQ/DMA settings detected (the default is to
1516 ignore detected IRQ/DMA settings because of
1517 possible conflicts). You can specify the base
1518 address, IRQ, and DMA settings; IRQ and DMA
1519 should be numbers, or 'auto' (for using detected
1520 settings on that particular port), or 'nofifo'
1521 (to avoid using a FIFO even if it is detected).
1522 Parallel ports are assigned in the order they
1523 are specified on the command line, starting
1526 parport_init_mode= [HW,PPT]
1527 Configure VIA parallel port to operate in
1528 a specific mode. This is necessary on Pegasos
1529 computer where firmware has no options for setting
1530 up parallel port mode and sets it to spp.
1531 Currently this function knows 686a and 8231 chips.
1532 Format: [spp|ps2|epp|ecp|ecpepp]
1534 pas2= [HW,OSS] Format:
1535 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1538 See header of drivers/scsi/pas16.c.
1541 Halt all CPUs after the first oops has been printed for
1542 the specified number of seconds. This is to be used if
1543 your oopses keep scrolling off the screen.
1548 See header of drivers/block/paride/pcd.c.
1549 See also Documentation/paride.txt.
1551 pci=option[,option...] [PCI] various PCI subsystem options:
1552 off [X86-32] don't probe for the PCI bus
1553 bios [X86-32] force use of PCI BIOS, don't access
1554 the hardware directly. Use this if your machine
1555 has a non-standard PCI host bridge.
1556 nobios [X86-32] disallow use of PCI BIOS, only direct
1557 hardware access methods are allowed. Use this
1558 if you experience crashes upon bootup and you
1559 suspect they are caused by the BIOS.
1560 conf1 [X86-32] Force use of PCI Configuration
1562 conf2 [X86-32] Force use of PCI Configuration
1564 noaer [PCIE] If the PCIEAER kernel config parameter is
1565 enabled, this kernel boot option can be used to
1566 disable the use of PCIE advanced error reporting.
1567 nodomains [PCI] Disable support for multiple PCI
1568 root domains (aka PCI segments, in ACPI-speak).
1569 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1571 nomsi [MSI] If the PCI_MSI kernel config parameter is
1572 enabled, this kernel boot option can be used to
1573 disable the use of MSI interrupts system-wide.
1574 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1575 routing table. These calls are known to be buggy
1576 on several machines and they hang the machine
1577 when used, but on other computers it's the only
1578 way to get the interrupt routing table. Try
1579 this option if the kernel is unable to allocate
1580 IRQs or discover secondary PCI buses on your
1582 rom [X86-32] Assign address space to expansion ROMs.
1583 Use with caution as certain devices share
1584 address decoders between ROMs and other
1586 norom [X86-32,X86_64] Do not assign address space to
1587 expansion ROMs that do not already have
1588 BIOS assigned address ranges.
1589 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1590 assigned automatically to PCI devices. You can
1591 make the kernel exclude IRQs of your ISA cards
1593 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1594 of the PIRQ table (normally generated
1595 by the BIOS) if it is outside the
1596 F0000h-100000h range.
1597 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1598 useful if the kernel is unable to find your
1599 secondary buses and you want to tell it
1600 explicitly which ones they are.
1601 assign-busses [X86-32] Always assign all PCI bus
1602 numbers ourselves, overriding
1603 whatever the firmware may have done.
1604 usepirqmask [X86-32] Honor the possible IRQ mask stored
1605 in the BIOS $PIR table. This is needed on
1606 some systems with broken BIOSes, notably
1607 some HP Pavilion N5400 and Omnibook XE3
1608 notebooks. This will have no effect if ACPI
1609 IRQ routing is enabled.
1610 noacpi [X86-32] Do not use ACPI for IRQ routing
1611 or for PCI scanning.
1612 use_crs [X86-32] Use _CRS for PCI resource
1614 routeirq Do IRQ routing for all PCI devices.
1615 This is normally done in pci_enable_device(),
1616 so this option is a temporary workaround
1617 for broken drivers that don't call it.
1618 skip_isa_align [X86] do not align io start addr, so can
1619 handle more pci cards
1620 firmware [ARM] Do not re-enumerate the bus but instead
1621 just use the configuration from the
1622 bootloader. This is currently used on
1623 IXP2000 systems where the bus has to be
1624 configured a certain way for adjunct CPUs.
1625 noearly [X86] Don't do any early type 1 scanning.
1626 This might help on some broken boards which
1627 machine check when some devices' config space
1628 is read. But various workarounds are disabled
1629 and some IOMMU drivers will not work.
1630 bfsort Sort PCI devices into breadth-first order.
1631 This sorting is done to get a device
1632 order compatible with older (<= 2.4) kernels.
1633 nobfsort Don't sort PCI devices into breadth-first order.
1634 cbiosize=nn[KMG] The fixed amount of bus space which is
1635 reserved for the CardBus bridge's IO window.
1636 The default value is 256 bytes.
1637 cbmemsize=nn[KMG] The fixed amount of bus space which is
1638 reserved for the CardBus bridge's memory
1639 window. The default value is 64 megabytes.
1641 pcmv= [HW,PCMCIA] BadgePAD 4
1644 See Documentation/paride.txt.
1646 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1649 See arch/parisc/kernel/pdc_chassis.c
1652 See Documentation/paride.txt.
1655 See Documentation/paride.txt.
1657 pirq= [SMP,APIC] Manual mp-table setup
1658 See Documentation/i386/IO-APIC.txt.
1660 plip= [PPT,NET] Parallel port network link
1661 Format: { parport<nr> | timid | 0 }
1662 See also Documentation/parport.txt.
1664 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1665 Override pmtimer IOPort with a hex value.
1672 { on | off | curr | res | no-curr | no-res }
1675 [ISAPNP] Exclude IRQs for the autoconfiguration
1678 [ISAPNP] Exclude DMAs for the autoconfiguration
1680 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1681 Ranges are in pairs (I/O port base and size).
1684 [ISAPNP] Exclude memory regions for the
1686 Ranges are in pairs (memory base and size).
1688 print-fatal-signals=
1689 [KNL] debug: print fatal signals
1690 print-fatal-signals=1: print segfault info to
1694 printk.time= Show timing data prefixed to each printk message line
1695 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1697 profile= [KNL] Enable kernel profiling via /proc/profile
1698 Format: [schedule,]<number>
1699 Param: "schedule" - profile schedule points.
1700 Param: <number> - step/bucket size as a power of 2 for
1701 statistical time based profiling.
1702 Param: "sleep" - profile D-state sleeping (millisecs).
1703 Requires CONFIG_SCHEDSTATS
1704 Param: "kvm" - profile VM exits.
1706 processor.max_cstate= [HW,ACPI]
1707 Limit processor to maximum C-state
1708 max_cstate=9 overrides any DMI blacklist limit.
1710 processor.nocst [HW,ACPI]
1711 Ignore the _CST method to determine C-states,
1712 instead using the legacy FADT method
1714 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1716 See Documentation/ramdisk.txt.
1718 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1719 probe for; one of (bare|imps|exps|lifebook|any).
1720 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1722 psmouse.resetafter= [HW,MOUSE]
1723 Try to reset the device after so many bad packets
1726 [HW,MOUSE] Set desired mouse resolution, in dpi.
1727 psmouse.smartscroll=
1728 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1729 0 = disabled, 1 = enabled (default).
1731 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1733 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1736 See Documentation/paride.txt.
1739 [KNL] Number of legacy pty's. Overwrites compiled-in
1742 quiet [KNL] Disable most log messages
1747 See Documentation/md.txt.
1749 ramdisk_blocksize= [RAM]
1750 See Documentation/ramdisk.txt.
1752 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1753 See Documentation/ramdisk.txt.
1755 rcupdate.blimit= [KNL,BOOT]
1756 Set maximum number of finished RCU callbacks to process
1759 rcupdate.qhimark= [KNL,BOOT]
1760 Set threshold of queued
1761 RCU callbacks over which batch limiting is disabled.
1763 rcupdate.qlowmark= [KNL,BOOT]
1764 Set threshold of queued RCU callbacks below which
1765 batch limiting is re-enabled.
1769 Run specified binary instead of /init from the ramdisk,
1770 used for early userspace startup. See initrd.
1772 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1773 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1774 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1777 [KNL, SMP] Set scheduler's default relax_domain_level.
1778 See Documentation/cpusets.txt.
1780 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1782 reservetop= [X86-32]
1784 Reserves a hole at the top of the kernel virtual
1787 reset_devices [KNL] Force drivers to reset the underlying device
1788 during initialization.
1791 Specify the partition device for software suspend
1793 resume_offset= [SWSUSP]
1794 Specify the offset from the beginning of the partition
1795 given by "resume=" at which the swap header is located,
1796 in <PAGE_SIZE> units (needed only for swap files).
1797 See Documentation/power/swsusp-and-swap-files.txt
1799 retain_initrd [RAM] Keep initrd memory after extraction
1801 rhash_entries= [KNL,NET]
1802 Set number of hash buckets for route cache
1804 riscom8= [HW,SERIAL]
1805 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1807 ro [KNL] Mount root device read-only on boot
1809 root= [KNL] Root filesystem
1811 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1812 mount the root filesystem
1814 rootflags= [KNL] Set root filesystem mount option string
1816 rootfstype= [KNL] Set root filesystem type
1818 rootwait [KNL] Wait (indefinitely) for root device to show up.
1819 Useful for devices that are detected asynchronously
1820 (e.g. USB and MMC devices).
1822 root_plug.vendor_id=
1823 [ROOTPLUG] Override the default vendor ID
1825 root_plug.product_id=
1826 [ROOTPLUG] Override the default product ID
1829 [ROOTPLUG] Enable debugging output
1831 rw [KNL] Mount root device read-write on boot
1833 S [KNL] Run init in single mode
1836 See drivers/net/irda/sa1100_ir.c.
1838 sbni= [NET] Granch SBNI12 leased line adapter
1840 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1841 Format: <io>[,<timeout>[,<isapnp>]]
1843 scsi_debug_*= [SCSI]
1844 See drivers/scsi/scsi_debug.c.
1846 scsi_default_dev_flags=
1847 [SCSI] SCSI default device flags
1850 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1851 Format: <vendor>:<model>:<flags>
1852 (flags are integer value)
1854 scsi_logging_level= [SCSI] a bit mask of logging levels
1855 See drivers/scsi/scsi_logging.h for bits. Also
1856 settable via sysctl at dev.scsi.logging_level
1857 (/proc/sys/dev/scsi/logging_level).
1858 There is also a nice 'scsi_logging_level' script in the
1859 S390-tools package, available for download at
1860 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1862 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1863 discovered. async scans them in kernel threads,
1864 allowing boot to proceed. none ignores them, expecting
1865 user space to do the scan.
1867 selinux [SELINUX] Disable or enable SELinux at boot time.
1868 Format: { "0" | "1" }
1869 See security/selinux/Kconfig help text.
1872 Default value is set via kernel config option.
1873 If enabled at boot time, /selinux/disable can be used
1874 later to disable prior to initial policy load.
1876 selinux_compat_net =
1877 [SELINUX] Set initial selinux_compat_net flag value.
1878 Format: { "0" | "1" }
1879 0 -- use new secmark-based packet controls
1880 1 -- use legacy packet controls
1881 Default value is 0 (preferred).
1882 Value can be changed at runtime via
1883 /selinux/compat_net.
1885 serialnumber [BUGS=X86-32]
1888 Maximal number of shapers.
1890 show_msr= [x86] show boot-time MSR settings
1891 Format: { <integer> }
1892 Show boot-time (BIOS-initialized) MSR settings.
1893 The parameter means the number of CPUs to show,
1894 for example 1 means boot CPU only.
1897 See header of drivers/scsi/sim710.c.
1904 slub_debug[=options[,slabs]] [MM, SLUB]
1905 Enabling slub_debug allows one to determine the
1906 culprit if slab objects become corrupted. Enabling
1907 slub_debug can create guard zones around objects and
1908 may poison objects when not in use. Also tracks the
1909 last alloc / free. For more information see
1910 Documentation/vm/slub.txt.
1912 slub_max_order= [MM, SLUB]
1913 Determines the maximum allowed order for slabs.
1914 A high setting may cause OOMs due to memory
1915 fragmentation. For more information see
1916 Documentation/vm/slub.txt.
1918 slub_min_objects= [MM, SLUB]
1919 The minimum number of objects per slab. SLUB will
1920 increase the slab order up to slub_max_order to
1921 generate a sufficiently large slab able to contain
1922 the number of objects indicated. The higher the number
1923 of objects the smaller the overhead of tracking slabs
1924 and the less frequently locks need to be acquired.
1925 For more information see Documentation/vm/slub.txt.
1927 slub_min_order= [MM, SLUB]
1928 Determines the mininum page order for slabs. Must be
1929 lower than slub_max_order.
1930 For more information see Documentation/vm/slub.txt.
1932 slub_nomerge [MM, SLUB]
1933 Disable merging of slabs with similar size. May be
1934 necessary if there is some reason to distinguish
1935 allocs to different slabs. Debug options disable
1936 merging on their own.
1937 For more information see Documentation/vm/slub.txt.
1940 Format: <io1>[,<io2>[,...,<io8>]]
1942 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1943 attempt to substitute SMP alternatives once at boot.
1945 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1946 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1947 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1948 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1949 smsc-ircc2.ircc_irq= [HW] IRQ line
1950 smsc-ircc2.ircc_dma= [HW] DMA channel
1951 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1952 0: Toshiba Satellite 1800 (GP data pin select)
1953 1: Fast pin select (default)
1956 snd-ad1816a= [HW,ALSA]
1958 snd-ad1848= [HW,ALSA]
1960 snd-ali5451= [HW,ALSA]
1962 snd-als100= [HW,ALSA]
1964 snd-als4000= [HW,ALSA]
1966 snd-azt2320= [HW,ALSA]
1968 snd-cmi8330= [HW,ALSA]
1970 snd-cmipci= [HW,ALSA]
1972 snd-cs4231= [HW,ALSA]
1974 snd-cs4232= [HW,ALSA]
1976 snd-cs4236= [HW,ALSA]
1978 snd-cs4281= [HW,ALSA]
1980 snd-cs46xx= [HW,ALSA]
1982 snd-dt019x= [HW,ALSA]
1984 snd-dummy= [HW,ALSA]
1986 snd-emu10k1= [HW,ALSA]
1988 snd-ens1370= [HW,ALSA]
1990 snd-ens1371= [HW,ALSA]
1992 snd-es968= [HW,ALSA]
1994 snd-es1688= [HW,ALSA]
1996 snd-es18xx= [HW,ALSA]
1998 snd-es1938= [HW,ALSA]
2000 snd-es1968= [HW,ALSA]
2002 snd-fm801= [HW,ALSA]
2004 snd-gusclassic= [HW,ALSA]
2006 snd-gusextreme= [HW,ALSA]
2008 snd-gusmax= [HW,ALSA]
2012 snd-ice1712= [HW,ALSA]
2014 snd-intel8x0= [HW,ALSA]
2016 snd-interwave= [HW,ALSA]
2021 snd-korg1212= [HW,ALSA]
2023 snd-maestro3= [HW,ALSA]
2025 snd-mpu401= [HW,ALSA]
2027 snd-mtpav= [HW,ALSA]
2029 snd-nm256= [HW,ALSA]
2031 snd-opl3sa2= [HW,ALSA]
2039 snd-opti93x= [HW,ALSA]
2043 snd-rme32= [HW,ALSA]
2045 snd-rme96= [HW,ALSA]
2047 snd-rme9652= [HW,ALSA]
2053 snd-sbawe= [HW,ALSA]
2055 snd-serial= [HW,ALSA]
2057 snd-sgalaxy= [HW,ALSA]
2059 snd-sonicvibes= [HW,ALSA]
2064 snd-sun-cs4231= [HW,ALSA]
2066 snd-trident= [HW,ALSA]
2068 snd-usb-audio= [HW,ALSA,USB]
2070 snd-via82xx= [HW,ALSA]
2072 snd-virmidi= [HW,ALSA]
2074 snd-wavefront= [HW,ALSA]
2076 snd-ymfpci= [HW,ALSA]
2079 [KNL] Should the soft-lockup detector generate panics.
2081 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2082 See Documentation/sonypi.txt
2084 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2085 See Documentation/specialix.txt.
2087 spia_io_base= [HW,MTD]
2093 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2095 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2096 See Documentation/scsi/st.txt.
2100 Set the STI (builtin display/keyboard on the HP-PARISC
2101 machines) console (graphic card) which should be used
2102 as the initial boot-console.
2103 See also comment in drivers/video/console/sticore.c.
2106 See comment in drivers/video/console/sticore.c.
2109 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2113 Control how the NFS server code allocates CPUs to
2114 service thread pools. Depending on how many NICs
2115 you have and where their interrupts are bound, this
2116 option will affect which CPUs will do NFS serving.
2117 Note: this parameter cannot be changed while the
2118 NFS server is running.
2120 auto the server chooses an appropriate mode
2121 automatically using heuristics
2122 global a single global pool contains all CPUs
2123 percpu one pool for each CPU
2124 pernode one pool for each NUMA node (equivalent
2125 to global on non-NUMA machines)
2127 swiotlb= [IA-64] Number of I/O TLB slabs
2131 sym53c416= [HW,SCSI]
2132 See header of drivers/scsi/sym53c416.c.
2134 sysrq_always_enabled
2136 Ignore sysrq setting - this boot parameter will
2137 neutralize any effect of /proc/sys/kernel/sysrq.
2138 Useful for debugging.
2141 See header of drivers/scsi/t128.c.
2145 test_suspend= [SUSPEND]
2146 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2147 standby suspend) as the system sleep state to briefly
2148 enter during system startup. The system is woken from
2149 this state using a wakeup-capable RTC alarm.
2151 thash_entries= [KNL,NET]
2152 Set number of hash buckets for TCP connection
2154 thermal.act= [HW,ACPI]
2155 -1: disable all active trip points in all thermal zones
2156 <degrees C>: override all lowest active trip points
2158 thermal.crt= [HW,ACPI]
2159 -1: disable all critical trip points in all thermal zones
2160 <degrees C>: lower all critical trip points
2162 thermal.nocrt= [HW,ACPI]
2163 Set to disable actions on ACPI thermal zone
2164 critical and hot trip points.
2166 thermal.off= [HW,ACPI]
2167 1: disable ACPI thermal control
2169 thermal.psv= [HW,ACPI]
2170 -1: disable all passive trip points
2171 <degrees C>: override all passive trip points to this value
2173 thermal.tzp= [HW,ACPI]
2174 Specify global default ACPI thermal zone polling rate
2175 <deci-seconds>: poll all this frequency
2176 0: no polling (default)
2179 See comment before function dc390_setup() in
2180 drivers/scsi/tmscsim.c.
2184 trix= [HW,OSS] MediaTrix AudioTrix Pro
2186 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2188 turbografx.map[2|3]= [HW,JOY]
2189 TurboGraFX parallel port interface
2191 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2192 See also Documentation/input/joystick-parport.txt
2194 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2195 See header of drivers/scsi/u14-34f.c.
2204 [USB] Ignore overcurrent events (default N).
2205 Some badly-designed motherboards generate lots of
2206 bogus events, for ports that aren't wired to
2207 anything. Set this parameter to avoid log spamming.
2208 Note that genuine overcurrent events won't be
2213 Set unknown_nmi_panic=1 early on boot.
2215 usbcore.autosuspend=
2216 [USB] The autosuspend time delay (in seconds) used
2217 for newly-detected USB devices (default 2). This
2218 is the time required before an idle device will be
2219 autosuspended. Devices for which the delay is set
2220 to a negative value won't be autosuspended at all.
2223 [USBHID] The interval which mice are to be polled at.
2225 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2226 kernel's map of available physical RAM.
2228 vdso= [X86-32,SH,x86-64]
2229 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2230 vdso=1: enable VDSO (default)
2231 vdso=0: disable VDSO mapping
2233 vdso32= [X86-32,X86-64]
2234 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2235 vdso32=1: enable 32-bit VDSO (default)
2236 vdso32=0: disable 32-bit VDSO mapping
2239 vector=percpu: enable percpu vector domain
2241 video= [FB] Frame buffer configuration
2242 See Documentation/fb/modedb.txt.
2244 vga= [BOOT,X86-32] Select a particular video mode
2245 See Documentation/i386/boot.txt and
2246 Documentation/svga.txt.
2247 Use vga=ask for menu.
2248 This is actually a boot loader parameter; the value is
2249 passed to the kernel using a special protocol.
2251 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2252 size of <nn>. This can be used to increase the
2253 minimum size (128MB on x86). It can also be used to
2254 decrease the size and leave more room for directly
2257 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2260 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2263 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2266 waveartist= [HW,OSS]
2267 Format: <io>,<irq>,<dma>,<dma2>
2270 See header of drivers/scsi/wd33c93.c.
2273 See header of drivers/scsi/wd7000.c.
2276 See Documentation/watchdog/wdt.txt.
2278 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2279 xd_geo= See header of drivers/block/xd.c.
2281 xirc2ps_cs= [NET,PCMCIA]
2283 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2285 norandmaps Don't use address space randomization
2286 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2288 ______________________________________________________________________
2292 Add documentation for ALSA options.
2293 Add more DRM drivers.
projects / linux-2.6 / blob