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 FTRACE Function tracing enabled.
93 TS Appropriate touchscreen support is enabled.
94 UMS USB Mass Storage support is enabled.
95 USB USB support is enabled.
96 USBHID USB Human Interface Device support is enabled.
97 V4L Video For Linux support is enabled.
98 VGA The VGA console has been enabled.
99 VT Virtual terminal support is enabled.
100 WDT Watchdog support is enabled.
101 XT IBM PC/XT MFM hard disk support is enabled.
102 X86-32 X86-32, aka i386 architecture is enabled.
103 X86-64 X86-64 architecture is enabled.
104 More X86-64 boot options can be found in
105 Documentation/x86/x86_64/boot-options.txt .
106 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
108 In addition, the following text indicates that the option:
110 BUGS= Relates to possible processor bugs on the said processor.
111 KNL Is a kernel start-up parameter.
112 BOOT Is a boot loader parameter.
114 Parameters denoted with BOOT are actually interpreted by the boot
115 loader, and have no meaning to the kernel directly.
116 Do not modify the syntax of boot loader parameters without extreme
117 need or coordination with <Documentation/x86/boot.txt>.
119 There are also arch-specific kernel-parameters not documented here.
120 See for example <Documentation/x86/x86_64/boot-options.txt>.
122 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
123 a trailing = on the name of any parameter states that that parameter will
124 be entered as an environment variable, whereas its absence indicates that
125 it will appear as a kernel argument readable via /proc/cmdline by programs
126 running once the system is up.
128 The number of kernel parameters is not limited, but the length of the
129 complete command line (parameters including spaces etc.) is limited to
130 a fixed number of characters. This limit depends on the architecture
131 and is between 256 and 4096 characters. It is defined in the file
132 ./include/asm/setup.h as COMMAND_LINE_SIZE.
135 acpi= [HW,ACPI,X86-64,i386]
136 Advanced Configuration and Power Interface
137 Format: { force | off | ht | strict | noirq | rsdt }
138 force -- enable ACPI if default was off
139 off -- disable ACPI if default was on
140 noirq -- do not use ACPI for IRQ routing
141 ht -- run only enough ACPI to enable Hyper Threading
142 strict -- Be less tolerant of platforms that are not
143 strictly ACPI specification compliant.
144 rsdt -- prefer RSDT over (default) XSDT
146 See also Documentation/power/pm.txt, pci=noacpi
148 acpi_apic_instance= [ACPI, IOAPIC]
150 2: use 2nd APIC table, if available
151 1,0: use 1st APIC table
154 acpi_sleep= [HW,ACPI] Sleep options
155 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
156 old_ordering, s4_nonvs }
157 See Documentation/power/video.txt for information on
159 s3_beep is for debugging; it makes the PC's speaker beep
160 as soon as the kernel's real-mode entry point is called.
161 s4_nohwsig prevents ACPI hardware signature from being
162 used during resume from hibernation.
163 old_ordering causes the ACPI 1.0 ordering of the _PTS
164 control method, with respect to putting devices into
165 low power states, to be enforced (the ACPI 2.0 ordering
166 of _PTS is used by default).
167 s4_nonvs prevents the kernel from saving/restoring the
168 ACPI NVS memory during hibernation.
170 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
171 Format: { level | edge | high | low }
173 acpi_irq_balance [HW,ACPI]
174 ACPI will balance active IRQs
177 acpi_irq_nobalance [HW,ACPI]
178 ACPI will not move active IRQs (default)
181 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
183 Format: <irq>,<irq>...
185 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
186 Format: <irq>,<irq>...
188 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
190 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
191 Format: To spoof as Windows 98: ="Microsoft Windows"
193 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
194 acpi_osi="string1" # add string1 -- only one string
195 acpi_osi="!string2" # remove built-in string2
196 acpi_osi= # disable all strings
198 acpi_serialize [HW,ACPI] force serialization of AML methods
200 acpi_skip_timer_override [HW,ACPI]
201 Recognize and ignore IRQ0/pin2 Interrupt Override.
202 For broken nForce2 BIOS resulting in XT-PIC timer.
203 acpi_use_timer_override [HW,ACPI]
204 Use timer override. For some broken Nvidia NF5 boards
205 that require a timer override, but don't have
208 acpi_backlight= [HW,ACPI]
209 acpi_backlight=vendor
211 If set to vendor, prefer vendor specific driver
212 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
213 of the ACPI video.ko driver.
215 acpi_display_output= [HW,ACPI]
216 acpi_display_output=vendor
217 acpi_display_output=video
220 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
221 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
223 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
224 debug output. Bits in debug_layer correspond to a
225 _COMPONENT in an ACPI source file, e.g.,
226 #define _COMPONENT ACPI_PCI_COMPONENT
227 Bits in debug_level correspond to a level in
228 ACPI_DEBUG_PRINT statements, e.g.,
229 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
230 The debug_level mask defaults to "info". See
231 Documentation/acpi/debug.txt for more information about
232 debug layers and levels.
234 Enable processor driver info messages:
235 acpi.debug_layer=0x20000000
236 Enable PCI/PCI interrupt routing info messages:
237 acpi.debug_layer=0x400000
238 Enable AML "Debug" output, i.e., stores to the Debug
239 object while interpreting AML:
240 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
241 Enable all messages related to ACPI hardware:
242 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
244 Some values produce so much output that the system is
245 unusable. The "log_buf_len" parameter may be useful
246 if you need to capture more output.
248 acpi.power_nocheck= [HW,ACPI]
249 Format: 1/0 enable/disable the check of power state.
250 On some bogus BIOS the _PSC object/_STA object of
251 power resource can't return the correct device power
252 state. In such case it is unneccessary to check its
253 power state again in power transition.
254 1 : disable the power state check
256 acpi_pm_good [X86-32,X86-64]
257 Override the pmtimer bug detection: force the kernel
258 to assume that this machine's pmtimer latches its value
259 and always returns good values.
262 { off | try_unsupported }
263 off: disable AGP support
264 try_unsupported: try to drive unsupported chipsets
265 (may crash computer or cause data corruption)
267 enable_timer_pin_1 [i386,x86-64]
268 Enable PIN 1 of APIC timer
269 Can be useful to work around chipset bugs
270 (in particular on some ATI chipsets).
271 The kernel tries to set a reasonable default.
273 disable_timer_pin_1 [i386,x86-64]
274 Disable PIN 1 of APIC timer
275 Can be useful to work around chipset bugs.
278 Format: <io>,<irq>,<dma>,<dma2>,<type>
281 See header of drivers/scsi/advansys.c.
283 advwdt= [HW,WDT] Advantech WDT
284 Format: <iostart>,<iostop>
286 aedsp16= [HW,OSS] Audio Excel DSP 16
287 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
288 See also header of sound/oss/aedsp16.c.
291 See Documentation/scsi/aha152x.txt.
294 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
297 See Documentation/scsi/aic7xxx.txt.
300 See Documentation/scsi/aic79xx.txt.
302 amd_iommu= [HW,X86-84]
303 Pass parameters to the AMD IOMMU driver in the system.
305 isolate - enable device isolation (each device, as far
306 as possible, will get its own protection
308 share - put every device behind one IOMMU into the
309 same protection domain
310 fullflush - enable flushing of IO/TLB entries when
311 they are unmapped. Otherwise they are
312 flushed before they will be reused, which
315 amd_iommu_size= [HW,X86-64]
316 Define the size of the aperture for the AMD IOMMU
317 driver. Possible values are:
318 '32M', '64M' (default), '128M', '256M', '512M', '1G'
320 amijoy.map= [HW,JOY] Amiga joystick support
321 Map of devices attached to JOY0DAT and JOY1DAT
323 See also Documentation/kernel/input/joystick.txt
325 analog.map= [HW,JOY] Analog joystick and gamepad support
326 Specifies type or capabilities of an analog joystick
327 connected to one of 16 gameports
328 Format: <type1>,<type2>,..<type16>
331 Power management functions (SPARCstation-4/5 + deriv.)
333 Disable APC CPU standby support. SPARCstation-Fox does
334 not play well with APC CPU idle - disable it if you have
335 APC and your system crashes randomly.
337 apic= [APIC,i386] Advanced Programmable Interrupt Controller
338 Change the output verbosity whilst booting
339 Format: { quiet (default) | verbose | debug }
340 Change the amount of debugging information output
341 when initialising the APIC and IO-APIC components.
343 apm= [APM] Advanced Power Management
344 See header of arch/x86/kernel/apm_32.c.
346 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
347 Format: <io>,<irq>,<nodeID>
351 atarimouse= [HW,MOUSE] Atari Mouse
353 atascsi= [HW,SCSI] Atari SCSI
355 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
356 EzKey and similar keyboards
358 atkbd.reset= [HW] Reset keyboard during initialization
360 atkbd.set= [HW] Select keyboard code set
361 Format: <int> (2 = AT (default), 3 = PS/2)
363 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
366 atkbd.softraw= [HW] Choose between synthetic and real raw mode
367 Format: <bool> (0 = real, 1 = synthetic (default))
369 atkbd.softrepeat= [HW]
370 Use software keyboard repeat
374 baycom_epp= [HW,AX25]
377 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
379 See header of drivers/net/hamradio/baycom_par.c.
381 baycom_ser_fdx= [HW,AX25]
382 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
383 Format: <io>,<irq>,<mode>[,<baud>]
384 See header of drivers/net/hamradio/baycom_ser_fdx.c.
386 baycom_ser_hdx= [HW,AX25]
387 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
388 Format: <io>,<irq>,<mode>
389 See header of drivers/net/hamradio/baycom_ser_hdx.c.
391 boot_delay= Milliseconds to delay each printk during boot.
392 Values larger than 10 seconds (10000) are changed to
396 bootmem_debug [KNL] Enable bootmem allocator debug messages.
398 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
399 bttv.radio= Most important insmod options are available as
401 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
402 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
405 See drivers/scsi/BusLogic.c, comment before function
406 BusLogic_ParseDriverOptions().
408 c101= [NET] Moxa C101 synchronous serial card
410 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
411 Sometimes CPU hardware bugs make them report the cache
412 size incorrectly. The kernel will attempt work arounds
413 to fix known problems, but for some CPUs it is not
414 possible to determine what the correct size should be.
415 This option provides an override for these situations.
417 security= [SECURITY] Choose a security module to enable at boot.
418 If this boot parameter is not specified, only the first
419 security module asking for security registration will be
420 loaded. An invalid security module name will be treated
421 as if no module has been chosen.
424 [SECURITY] Disable capabilities. This would normally
425 be used only if an alternative security model is to be
426 configured. Potentially dangerous and should only be
427 used if you are entirely sure of the consequences.
429 ccw_timeout_log [S390]
430 See Documentation/s390/CommonIO for details.
432 cgroup_disable= [KNL] Disable a particular controller
433 Format: {name of the controller(s) to disable}
434 {Currently supported controllers - "memory"}
436 checkreqprot [SELINUX] Set initial checkreqprot flag value.
437 Format: { "0" | "1" }
438 See security/selinux/Kconfig help text.
439 0 -- check protection applied by kernel (includes
440 any implied execute protection).
441 1 -- check protection requested by application.
442 Default value is set via a kernel config option.
443 Value can be changed at runtime via
444 /selinux/checkreqprot.
447 See Documentation/s390/CommonIO for details.
449 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
451 Forces specified clocksource (if available) to be used
452 when calculating gettimeofday(). If specified
453 clocksource is not available, it defaults to PIT.
454 Format: { pit | tsc | cyclone | pmtmr }
456 clocksource= [GENERIC_TIME] Override the default clocksource
458 Override the default clocksource and use the clocksource
459 with the name specified.
460 Some clocksource names to choose from, depending on
462 [all] jiffies (this is the base, fallback clocksource)
464 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
465 pxa_timer,timer3,32k_counter,timer0_1
467 [X86-32] pit,hpet,tsc,vmi-timer;
468 scx200_hrt on Geode; cyclone on IBM x440
476 clearcpuid=BITNUM [X86]
477 Disable CPUID feature X for the kernel. See
478 arch/x86/include/asm/cpufeature.h for the valid bit
479 numbers. Note the Linux specific bits are not necessarily
480 stable over kernel options, but the vendor specific
482 Also note that user programs calling CPUID directly
483 or using the feature without checking anything
484 will still see it. This just prevents it from
485 being used by the kernel or shown in /proc/cpuinfo.
486 Also note the kernel might malfunction if you disable
489 code_bytes [IA32/X86_64] How many bytes of object code to print
494 hpet= [X86-32,HPET] option to control HPET usage
495 Format: { enable (default) | disable | force }
496 disable: disable HPET and use PIT instead
497 force: allow force enabled of undocumented chips (ICH4,
500 com20020= [HW,NET] ARCnet - COM20020 chipset
502 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
504 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
508 ARCnet - COM90xx chipset (memory-mapped buffers)
509 Format: <io>[,<irq>[,<memstart>]]
511 condev= [HW,S390] console device
514 console= [KNL] Output console device and options.
516 tty<n> Use the virtual console device <n>.
520 Use the specified serial port. The options are of
521 the form "bbbbpnf", where "bbbb" is the baud rate,
522 "p" is parity ("n", "o", or "e"), "n" is number of
523 bits, and "f" is flow control ("r" for RTS or
524 omit it). Default is "9600n8".
526 See Documentation/serial-console.txt for more
528 Documentation/networking/netconsole.txt for an
531 uart[8250],io,<addr>[,options]
532 uart[8250],mmio,<addr>[,options]
533 Start an early, polled-mode console on the 8250/16550
534 UART at the specified I/O port or MMIO address,
535 switching to the matching ttyS device later. The
536 options are the same as for ttyS, above.
538 If the device connected to the port is not a TTY but a braille
539 device, prepend "brl," before the device type, for instance
541 For now, only VisioBraille is supported.
543 earlycon= [KNL] Output early console device and options.
544 uart[8250],io,<addr>[,options]
545 uart[8250],mmio,<addr>[,options]
546 Start an early, polled-mode console on the 8250/16550
547 UART at the specified I/O port or MMIO address.
548 The options are the same as for ttyS, above.
551 [HW] Never suspend the console
552 Disable suspending of consoles during suspend and
553 hibernate operations. Once disabled, debugging
554 messages can reach various consoles while the rest
555 of the system is being put to sleep (ie, while
556 debugging driver suspend/resume hooks). This may
557 not work reliably with all consoles, but is known
558 to work with serial and VGA consoles.
561 [KNL] Change the default value for
562 /proc/<pid>/coredump_filter.
563 See also Documentation/filesystems/proc.txt.
565 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
567 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
569 crashkernel=nn[KMG]@ss[KMG]
570 [KNL] Reserve a chunk of physical memory to
571 hold a kernel to switch to with kexec on panic.
573 crashkernel=range1:size1[,range2:size2,...][@offset]
574 [KNL] Same as above, but depends on the memory
575 in the running system. The syntax of range is
576 start-[end] where start and end are both
577 a memory unit (amount[KMG]). See also
578 Documentation/kdump/kdump.txt for a example.
583 cs89x0_media= [HW,NET]
584 Format: { rj45 | aui | bnc }
587 See header of drivers/s390/block/dasd_devmap.c.
589 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
590 (one device per port)
591 Format: <port#>,<type>
592 See also Documentation/input/joystick-parport.txt
594 debug [KNL] Enable kernel debugging (events log level).
597 [KNL] verbose self-tests
599 Print debugging info while doing the locking API
601 We default to 0 (no extra messages), setting it to
602 1 will print _a lot_ more information - normally
603 only useful to kernel developers.
605 debug_objects [KNL] Enable object debugging
607 debugpat [X86] Enable PAT debugging
609 decnet.addr= [HW,NET]
610 Format: <area>[,<node>]
611 See also Documentation/networking/decnet.txt.
614 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
615 Change the default blue palette of the console.
616 This is a 16-member array composed of values
620 Format: <green0>,<green1>,<green2>,...,<green15>
621 Change the default green palette of the console.
622 This is a 16-member array composed of values
626 Format: <red0>,<red1>,<red2>,...,<red15>
627 Change the default red palette of the console.
628 This is a 16-member array composed of values
634 Set system-wide default UTF-8 mode for all tty's.
635 Default is 1, i.e. UTF-8 mode is enabled for all
636 newly opened terminals.
639 Set number of hash buckets for dentry cache.
642 IO parameters + enable/disable command.
644 digiepca= [HW,SERIAL]
645 See drivers/char/README.epca and
646 Documentation/serial/digiepca.txt.
648 disable_mtrr_cleanup [X86]
649 enable_mtrr_cleanup [X86]
650 The kernel tries to adjust MTRR layout from continuous
651 to discrete, to make X server driver able to add WB
652 entry later. This parameter enables/disables that.
654 mtrr_chunk_size=nn[KMG] [X86]
655 used for mtrr cleanup. It is largest continous chunk
656 that could hold holes aka. UC entries.
658 mtrr_gran_size=nn[KMG] [X86]
659 Used for mtrr cleanup. It is granularity of mtrr block.
661 Large value could prevent small alignment from
664 mtrr_spare_reg_nr=n [X86]
666 Range: 0,7 : spare reg number
668 Used for mtrr cleanup. It is spare mtrr entries number.
669 Set to 2 or more if your graphical card needs more.
671 disable_mtrr_trim [X86, Intel and AMD only]
672 By default the kernel will trim any uncacheable
673 memory out of your available memory pool based on
674 MTRR settings. This parameter disables that behavior,
675 possibly causing your machine to run very slowly.
677 dmasound= [HW,OSS] Sound subsystem buffers
683 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
685 earlyprintk=serial[,ttySn[,baudrate]]
688 Append ",keep" to not disable it when the real console
691 Only vga or serial or usb debug port at a time.
693 Currently only ttyS0 and ttyS1 are supported.
695 Interaction with the standard serial driver is not
698 The VGA output is eventually overwritten by the real
704 Format: {"off" | "on" | "skip[mbr]"}
706 eisa_irq_edge= [PARISC,HW]
707 See header of drivers/parisc/eisa.c.
710 See comment before function elanfreq_setup() in
711 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
714 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
715 See Documentation/block/as-iosched.txt and
716 Documentation/block/deadline-iosched.txt for details.
718 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
719 Specifies physical address of start of kernel core
720 image elf header. Generally kexec loader will
721 pass this option to capture kernel.
722 See Documentation/kdump/kdump.txt for details.
724 enforcing [SELINUX] Set initial enforcing status.
726 See security/selinux/Kconfig help text.
727 0 -- permissive (log only, no denials).
728 1 -- enforcing (deny and log).
730 Value can be changed at runtime via /selinux/enforce.
732 ether= [HW,NET] Ethernet cards parameters
733 This option is obsoleted by the "netdev=" option, which
734 has equivalent usage. See its documentation for details.
736 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
741 fail_make_request=[KNL]
742 General fault injection mechanism.
743 Format: <interval>,<probability>,<space>,<times>
744 See also /Documentation/fault-injection/.
747 See header of drivers/scsi/fd_mcs.c.
750 See header of drivers/scsi/fdomain.c.
753 See Documentation/blockdev/floppy.txt.
755 force_pal_cache_flush
756 [IA-64] Avoid check_sal_cache_flush which may hang on
757 buggy SAL_CACHE_FLUSH implementations. Using this
758 parameter will force ia64_sal_cache_flush to call
759 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
762 [ftrace] will set and start the specified tracer
763 as early as possible in order to facilitate early
767 [ftrace] will dump the trace buffers on oops.
770 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
771 support via parallel port (up to 5 devices per port)
772 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
773 See also Documentation/input/joystick-parport.txt
777 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
782 See header of drivers/scsi/gdth.c.
784 gpt [EFI] Forces disk with valid GPT signature but
785 invalid Protective MBR to be treated as GPT.
789 hashdist= [KNL,NUMA] Large hashes allocated during boot
790 are distributed across NUMA nodes. Defaults on
791 for IA-64, off otherwise.
792 Format: 0 | 1 (for off | on)
794 hcl= [IA-64] SGI's Hardware Graph compatibility layer
796 hd= [EIDE] (E)IDE hard drive subsystem geometry
797 Format: <cyl>,<head>,<sect>
799 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
800 size of <nn>. This works even on boxes that have no
801 highmem otherwise. This also works to reduce highmem
802 size on bigger boxes.
804 highres= [KNL] Enable/disable high resolution timer mode.
805 Valid parameters: "on", "off"
809 See Documentation/isdn/README.HiSax.
811 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
812 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
813 On x86-64 and powerpc, this option can be specified
814 multiple times interleaved with hugepages= to reserve
815 huge pages of different sizes. Valid pages sizes on
816 x86-64 are 2M (when the CPU supports "pse") and 1G
817 (when the CPU supports the "pdpe1gb" cpuinfo flag)
818 Note that 1GB pages can only be allocated at boot time
819 using hugepages= and not freed afterwards.
821 [same as hugepagesz=] The size of the default
822 HugeTLB page size. This is the size represented by
823 the legacy /proc/ hugepages APIs, used for SHM, and
824 default size when mounting hugetlbfs filesystems.
825 Defaults to the default architecture's huge page size
830 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
831 terminal devices. Valid values: 0..8
833 i8042.debug [HW] Toggle i8042 debug mode
834 i8042.direct [HW] Put keyboard port into non-translated mode
835 i8042.dumbkbd [HW] Pretend that controller can only read data from
836 keyboard and cannot control its state
837 (Don't attempt to blink the leds)
838 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
839 i8042.nokbd [HW] Don't check/create keyboard port
840 i8042.noloop [HW] Disable the AUX Loopback command while probing
842 i8042.nomux [HW] Don't check presence of an active multiplexing
844 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
847 [HW] Frequency with which keyboard LEDs should blink
848 when kernel panics (default is 0.5 sec)
849 i8042.reset [HW] Reset the controller during init and cleanup
850 i8042.unlock [HW] Unlock (ignore) the keylock
854 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
855 indicates that the driver is running on unsupported
857 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
858 does not match list of supported models.
860 [HW] Report power status in /proc/i8k
861 (disabled by default)
862 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
865 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
866 See Documentation/mca.txt.
869 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
871 ide-core.nodma= [HW] (E)IDE subsystem
872 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
873 .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
874 .chs .ignore_cable are additional options
875 See Documentation/ide/ide.txt.
877 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
878 See Documentation/ide/ide.txt.
881 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
882 Poll forces a polling idle loop that can slightly
883 improve the performance of waking up a idle CPU, but
884 will use a lot of power and make the system run hot.
886 idle=mwait: On systems which support MONITOR/MWAIT but
887 the kernel chose to not use it because it doesn't save
888 as much power as a normal idle loop, use the
889 MONITOR/MWAIT idle loop anyways. Performance should be
890 the same as idle=poll.
891 idle=halt: Halt is forced to be used for CPU idle.
892 In such case C2/C3 won't be used again.
893 idle=nomwait: Disable mwait for CPU C-states
895 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
896 Claim all unknown PCI IDE storage controllers.
898 ignore_loglevel [KNL]
899 Ignore loglevel setting - this will print /all/
900 kernel messages to the console. Useful for debugging.
903 Set number of hash buckets for inode cache.
906 See header of drivers/scsi/in2000.c.
910 Run specified binary instead of /sbin/init as init
913 initcall_debug [KNL] Trace initcalls as they are executed. Useful
914 for working out where the kernel is dying during
917 initrd= [BOOT] Specify the location of the initial ramdisk
919 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
924 iomem= Disable strict checking of access to MMIO memory
925 strict regions from userspace.
941 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
943 Enable intel iommu driver.
945 Disable intel iommu driver.
946 igfx_off [Default Off]
947 By default, gfx is mapped as normal device. If a gfx
948 device has a dedicated DMAR unit, the DMAR unit is
949 bypassed by not enabling DMAR with this option. In
950 this case, gfx device will use physical address for
953 With this option iommu will not optimize to look
954 for io virtual address below 32 bit forcing dual
955 address cycle on pci bus for cards supporting greater
956 than 32 bit addressing. The default is to look
957 for translation below 32 bit and if not available
958 then look in the higher range.
960 With this option on every unmap_single operation will
961 result in a hardware IOTLB flush operation as opposed
962 to batching them for performance.
964 io_delay= [X86-32,X86-64] I/O delay method
966 Standard port 0x80 based delay
968 Alternate port 0xed based delay (needed on some systems)
970 Simple two microseconds delay
974 io7= [HW] IO7 for Marvel based alpha systems
975 See comment before marvel_specify_io7 in
976 arch/alpha/kernel/core_marvel.c.
979 See Documentation/filesystems/nfsroot.txt.
981 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
982 See comment before ip2_setup() in
983 drivers/char/ip2/ip2base.c.
985 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
986 See header of drivers/scsi/ips.c.
988 ports= [IP_VS_FTP] IPVS ftp helper module
990 Up to 8 (IP_VS_APP_MAX_PORTS) ports
992 Format: <port>,<port>....
995 When an interrupt is not handled search all handlers
996 for it. Intended to get systems with badly broken
1000 When an interrupt is not handled search all handlers
1001 for it. Also check all handlers each timer
1002 interrupt. Intended to get systems with badly broken
1006 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1008 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1010 <cpu number>,...,<cpu number>
1012 <cpu number>-<cpu number>
1013 (must be a positive range in ascending order)
1015 <cpu number>,...,<cpu number>-<cpu number>
1017 This option can be used to specify one or more CPUs
1018 to isolate from the general SMP balancing and scheduling
1019 algorithms. You can move a process onto or off an
1020 "isolated" CPU via the CPU affinity syscalls or cpuset.
1021 <cpu number> begins at 0 and the maximum value is
1022 "number of CPUs in system - 1".
1024 This option is the preferred way to isolate CPUs. The
1025 alternative -- manually setting the CPU mask of all
1026 tasks in the system -- can cause problems and
1027 suboptimal load balancer performance.
1031 js= [HW,JOY] Analog joystick
1032 See Documentation/input/joystick.txt.
1034 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1035 specifies the amount of memory usable by the kernel
1036 for non-movable allocations. The requested amount is
1037 spread evenly throughout all nodes in the system. The
1038 remaining memory in each node is used for Movable
1039 pages. In the event, a node is too small to have both
1040 kernelcore and Movable pages, kernelcore pages will
1041 take priority and other nodes will have a larger number
1042 of kernelcore pages. The Movable zone is used for the
1043 allocation of pages that may be reclaimed or moved
1044 by the page migration subsystem. This means that
1045 HugeTLB pages may not be allocated from this zone.
1046 Note that allocations like PTEs-from-HighMem still
1047 use the HighMem zone if it exists, and the Normal
1048 zone if it does not.
1050 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1051 is similar to kernelcore except it specifies the
1052 amount of memory used for migratable allocations.
1053 If both kernelcore and movablecore is specified,
1054 then kernelcore will be at *least* the specified
1055 value but may be more. If movablecore on its own
1056 is specified, the administrator must be careful
1057 that the amount of memory usable for all allocations
1062 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1065 kgdboc= [HW] kgdb over consoles.
1066 Requires a tty driver that supports console polling.
1067 (only serial suported for now)
1068 Format: <serial_device>[,baud]
1070 kmac= [MIPS] korina ethernet MAC address.
1071 Configure the RouterBoard 532 series on-chip
1072 Ethernet adapter MAC address.
1078 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1081 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer
1084 libata.dma= [LIBATA] DMA control
1085 libata.dma=0 Disable all PATA and SATA DMA
1086 libata.dma=1 PATA and SATA Disk DMA only
1087 libata.dma=2 ATAPI (CDROM) DMA only
1088 libata.dma=4 Compact Flash DMA only
1089 Combinations also work, so libata.dma=3 enables DMA
1090 for disks and CDROMs, but not CFs.
1092 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1096 libata.force= [LIBATA] Force configurations. The format is comma
1097 separated list of "[ID:]VAL" where ID is
1098 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1099 matching port, link or device. Basically, it matches
1100 the ATA ID string printed on console by libata. If
1101 the whole ID part is omitted, the last PORT and DEVICE
1102 values are used. If ID hasn't been specified yet, the
1103 configuration applies to all ports, links and devices.
1105 If only DEVICE is omitted, the parameter applies to
1106 the port and all links and devices behind it. DEVICE
1107 number of 0 either selects the first device or the
1108 first fan-out link behind PMP device. It does not
1109 select the host link. DEVICE number of 15 selects the
1110 host link and device attached to it.
1112 The VAL specifies the configuration to force. As long
1113 as there's no ambiguity shortcut notation is allowed.
1114 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1115 The following configurations can be forced.
1117 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1118 Any ID with matching PORT is used.
1120 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1122 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1123 udma[/][16,25,33,44,66,100,133] notation is also
1126 * [no]ncq: Turn on or off NCQ.
1128 * nohrst, nosrst, norst: suppress hard, soft
1131 If there are multiple matching configurations changing
1132 the same attribute, the last one is used.
1134 lmb=debug [KNL] Enable lmb debug messages.
1136 load_ramdisk= [RAM] List of ramdisks to load from floppy
1137 See Documentation/blockdev/ramdisk.txt.
1139 lockd.nlm_grace_period=P [NFS] Assign grace period.
1142 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1145 lockd.nlm_timeout=T [NFS] Assign timeout value.
1148 lockd.nlm_udpport=M [NFS] Assign UDP port.
1151 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1154 loglevel= All Kernel Messages with a loglevel smaller than the
1155 console loglevel will be printed to the console. It can
1156 also be changed with klogd or other programs. The
1157 loglevels are defined as follows:
1159 0 (KERN_EMERG) system is unusable
1160 1 (KERN_ALERT) action must be taken immediately
1161 2 (KERN_CRIT) critical conditions
1162 3 (KERN_ERR) error conditions
1163 4 (KERN_WARNING) warning conditions
1164 5 (KERN_NOTICE) normal but significant condition
1165 6 (KERN_INFO) informational
1166 7 (KERN_DEBUG) debug-level messages
1168 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1169 Format: { n | nk | nM }
1170 n must be a power of two. The default size
1171 is set in the kernel config file.
1173 logo.nologo [FB] Disables display of the built-in Linux logo.
1174 This may be used to provide more screen space for
1175 kernel log messages and is useful when debugging
1176 kernel boot problems.
1178 lp=0 [LP] Specify parallel ports to use, e.g,
1179 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1180 lp=reset first parallel port). 'lp=0' disables the
1181 lp=auto printer driver. 'lp=reset' (which can be
1182 specified in addition to the ports) causes
1183 attached printers to be reset. Using
1184 lp=port1,port2,... specifies the parallel ports
1185 to associate lp devices with, starting with
1186 lp0. A port specification may be 'none' to skip
1187 that lp device, or a parport name such as
1188 'parport0'. Specifying 'lp=auto' instead of a
1189 port specification list means that device IDs
1190 from each port should be examined, to see if
1191 an IEEE 1284-compliant printer is attached; if
1192 so, the driver will manage that printer.
1193 See also header of drivers/char/lp.c.
1196 Sets loops_per_jiffy to given constant, thus avoiding
1197 time-consuming boot-time autodetection (up to 250 ms per
1198 CPU). 0 enables autodetection (default). To determine
1199 the correct value for your kernel, boot with normal
1200 autodetection and see what value is printed. Note that
1201 on SMP systems the preset will be applied to all CPUs,
1202 which is likely to cause problems if your CPUs need
1203 significantly divergent settings. An incorrect value
1204 will cause delays in the kernel to be wrong, leading to
1205 unpredictable I/O errors and other breakage. Although
1206 unlikely, in the extreme case this might damage your
1210 Format: <io>,<irq>,<dma>
1212 mac5380= [HW,SCSI] Format:
1213 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1215 machvec= [IA64] Force the use of a particular machine-vector
1216 (machvec) in a generic kernel.
1217 Example: machvec=hpzx1_swiotlb
1219 max_loop= [LOOP] Maximum number of loopback devices that can
1223 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1224 should make use of. maxcpus=n : n >= 0 limits the
1225 kernel to using 'n' processors. n=0 is a special case,
1226 it is equivalent to "nosmp", which also disables
1229 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
1230 or equal to this physical address is ignored.
1232 max_luns= [SCSI] Maximum number of LUNs to probe.
1233 Should be between 1 and 2^32-1.
1236 [SCSI] Maximum number of LUNs received.
1237 Should be between 1 and 16384.
1241 mce [X86-32] Machine Check Exception
1243 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1245 md= [HW] RAID subsystems devices and level
1246 See Documentation/md.txt.
1249 Format: <first>,<last>
1250 Specifies range of consoles to be captured by the MDA.
1252 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1253 Amount of memory to be used when the kernel is not able
1254 to see the whole system memory or for test.
1255 [X86-32] Use together with memmap= to avoid physical
1256 address space collisions. Without memmap= PCI devices
1257 could be placed at addresses belonging to unused RAM.
1259 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1263 [KNL,SH] Allow user to override the default size for
1264 per-device physically contiguous DMA buffers.
1266 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1267 E820 memory map, as specified by the user.
1268 Such memmap=exactmap lines can be constructed based on
1269 BIOS output or other requirements. See the memmap=nn@ss
1272 memmap=nn[KMG]@ss[KMG]
1273 [KNL] Force usage of a specific region of memory
1274 Region of memory to be used, from ss to ss+nn.
1276 memmap=nn[KMG]#ss[KMG]
1277 [KNL,ACPI] Mark specific memory as ACPI data.
1278 Region of memory to be used, from ss to ss+nn.
1280 memmap=nn[KMG]$ss[KMG]
1281 [KNL,ACPI] Mark specific memory as reserved.
1282 Region of memory to be used, from ss to ss+nn.
1283 Example: Exclude memory from 0x18690000-0x1869ffff
1284 memmap=64K$0x18690000
1286 memmap=0x10000$0x18690000
1288 memory_corruption_check=0/1 [X86]
1289 Some BIOSes seem to corrupt the first 64k of
1290 memory when doing things like suspend/resume.
1291 Setting this option will scan the memory
1292 looking for corruption. Enabling this will
1293 both detect corruption and prevent the kernel
1294 from using the memory being corrupted.
1295 However, its intended as a diagnostic tool; if
1296 repeatable BIOS-originated corruption always
1297 affects the same memory, you can use memmap=
1298 to prevent the kernel from using that memory.
1300 memory_corruption_check_size=size [X86]
1301 By default it checks for corruption in the low
1302 64k, making this memory unavailable for normal
1303 use. Use this parameter to scan for
1304 corruption in more or less memory.
1306 memory_corruption_check_period=seconds [X86]
1307 By default it checks for corruption every 60
1308 seconds. Use this parameter to check at some
1309 other rate. 0 disables periodic checking.
1311 memtest= [KNL,X86] Enable memtest
1313 range: 0,4 : pattern number
1314 default : 0 <disable>
1316 meye.*= [HW] Set MotionEye Camera parameters
1317 See Documentation/video4linux/meye.txt.
1319 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1320 Multi-Function General Purpose Timers on AMD Geode
1323 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1324 the BIOS has incorrectly applied a workaround. TinyBIOS
1325 version 0.98 is known to be affected, 0.99 fixes the
1326 problem by letting the user disable the workaround.
1330 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1331 physical address is ignored.
1334 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1335 parameter allows control of the logging verbosity for
1336 the additional memory initialisation checks. A value
1337 of 0 disables mminit logging and a level of 4 will
1338 log everything. Information is printed at KERN_DEBUG
1339 so loglevel=8 may also need to be specified.
1342 [MOUSE] Maximum time between finger touching and
1343 leaving touchpad surface for touch to be considered
1344 a tap and be reported as a left button click (for
1345 touchpads working in absolute mode only).
1347 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1348 reporting absolute coordinates, such as tablets
1349 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1350 reporting absolute coordinates, such as tablets
1355 MTD_Partition= [MTD]
1356 Format: <name>,<region-number>,<size>,<offset>
1358 MTD_Region= [MTD] Format:
1359 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1362 See drivers/mtd/cmdlinepart.c.
1365 ARM/S3C2412 JIVE boot control
1367 See arch/arm/mach-s3c2412/mach-jive.c
1369 mtouchusb.raw_coordinates=
1370 [HW] Make the MicroTouch USB driver use raw coordinates
1371 ('y', default) or cooked coordinates ('n')
1373 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1376 See header of drivers/scsi/NCR_D700.c.
1380 ncr53c400= [HW,SCSI]
1382 ncr53c400a= [HW,SCSI]
1384 ncr53c406a= [HW,SCSI]
1386 ncr53c8xx= [HW,SCSI]
1388 netdev= [NET] Network devices parameters
1389 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1390 Note that mem_start is often overloaded to mean
1391 something different and driver-specific.
1392 This usage is only documented in each driver source
1396 [NETFILTER] Enable connection tracking flow accounting
1397 0 to disable accounting
1398 1 to enable accounting
1399 Default value depends on CONFIG_NF_CT_ACCT that is
1400 going to be removed in 2.6.29.
1403 See Documentation/filesystems/nfsroot.txt.
1405 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1406 See Documentation/filesystems/nfsroot.txt.
1408 nfs.callback_tcpport=
1409 [NFS] set the TCP port on which the NFSv4 callback
1410 channel should listen.
1412 nfs.idmap_cache_timeout=
1413 [NFS] set the maximum lifetime for idmapper cache
1417 [NFS] enable 64-bit inode numbers.
1418 If zero, the NFS client will fake up a 32-bit inode
1419 number for the readdir() and stat() syscalls instead
1420 of returning the full 64-bit number.
1421 The default is to return 64-bit inode numbers.
1423 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1424 when a NMI is triggered.
1425 Format: [state][,regs][,debounce][,die]
1427 nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
1428 Format: [panic,][num]
1430 0 - turn nmi_watchdog off
1431 1 - use the IO-APIC timer for the NMI watchdog
1432 2 - use the local APIC for the NMI watchdog using
1433 a performance counter. Note: This will use one performance
1434 counter and the local APIC's performance vector.
1435 When panic is specified panic when an NMI watchdog timeout occurs.
1436 This is useful when you use a panic=... timeout and need the box
1438 Instead of 1 and 2 it is possible to use the following
1439 symbolic names: lapic and ioapic
1440 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1442 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1443 emulation library even if a 387 maths coprocessor
1446 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1447 caches in the slab allocator. Saves per-node memory,
1448 but will impact performance.
1452 noapic [SMP,APIC] Tells the kernel to not make use of any
1453 IOAPICs that may be present in the system.
1455 nobats [PPC] Do not use BATs for mapping kernel lowmem
1456 on "Classic" PPC cores.
1460 nodelayacct [KNL] Disable per-task delay accounting
1462 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1464 nodsp [SH] Disable hardware DSP at boot time.
1466 noefi [X86-32,X86-64] Disable EFI runtime services support.
1470 noexec [X86-32,X86-64]
1471 On X86-32 available only on PAE configured kernels.
1472 noexec=on: enable non-executable mappings (default)
1473 noexec=off: disable non-executable mappings
1476 This affects only 32-bit executables.
1477 noexec32=on: enable non-executable mappings (default)
1478 read doesn't imply executable mappings
1479 noexec32=off: disable non-executable mappings
1480 read implies executable mappings
1482 nofpu [SH] Disable hardware FPU at boot time.
1484 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1485 register save and restore. The kernel will only save
1486 legacy floating-point registers on task switch.
1488 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1492 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1493 instruction doesn't work correctly and not to
1496 no_file_caps Tells the kernel not to honor file capabilities. The
1497 only way then for a file to be executed with privilege
1498 is to be setuid root or executed by root.
1500 nohalt [IA-64] Tells the kernel not to use the power saving
1501 function PAL_HALT_LIGHT when idle. This increases
1502 power-consumption. On the positive side, it reduces
1503 interrupt wake-up latency, which may improve performance
1504 in certain environments such as networked servers or
1507 nohz= [KNL] Boottime enable/disable dynamic ticks
1508 Valid arguments: on, off
1511 noirqdebug [X86-32] Disables the code which attempts to detect and
1512 disable unhandled interrupt sources.
1514 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1515 broken timer IRQ sources.
1517 noisapnp [ISAPNP] Disables ISA PnP code.
1519 noinitrd [RAM] Tells the kernel not to load any configured
1524 nojitter [IA64] Disables jitter checking for ITC timers.
1526 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1528 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1530 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1532 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1533 default x2apic cluster mode on platforms
1536 noltlbs [PPC] Do not use large page/tlb entries for kernel
1537 lowmem mapping on PPC40x.
1539 nomca [IA-64] Disable machine check abort handling
1541 nomce [X86-32] Machine Check Exception
1543 nomfgpt [X86-32] Disable Multi-Function General Purpose
1544 Timer usage (for AMD Geode machines).
1546 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1548 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1549 with UP alternatives
1551 noresidual [PPC] Don't use residual data on PReP machines.
1553 noresume [SWSUSP] Disables resume and restores original swap
1556 no-scroll [VGA] Disables scrollback.
1557 This is required for the Braillex ib80-piezo Braille
1558 reader made by F.H. Papenmeier (Germany).
1562 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1564 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1565 and disable the IO APIC. legacy for "maxcpus=0".
1567 nosoftlockup [KNL] Disable the soft-lockup detector.
1569 noswapaccount [KNL] Disable accounting of swap in memory resource
1570 controller. (See Documentation/controllers/memory.txt)
1572 nosync [HW,M68K] Disables sync negotiation for all devices.
1574 notsc [BUGS=X86-32] Disable Time Stamp Counter
1576 nousb [USB] Disable the USB subsystem
1580 nptcg= [IA64] Override max number of concurrent global TLB
1581 purges which is reported from either PAL_VM_SUMMARY or
1584 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1585 one of ['zone', 'node', 'default'] can be specified
1586 This can be set from sysctl after boot.
1587 See Documentation/sysctl/vm.txt for details.
1589 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1591 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1592 See Documentation/debugging-via-ohci1394.txt for more
1595 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1596 Rather than timing out after 20 ms if an EC
1597 command is not properly ACKed, override the length
1598 of the timeout. We have interrupts disabled while
1599 waiting for the ACK, so if this is set too high
1600 interrupts *may* be lost!
1605 oprofile.timer= [HW]
1606 Use timer interrupt instead of performance counters
1608 osst= [HW,SCSI] SCSI Tape Driver
1609 Format: <buffer_size>,<write_threshold>
1610 See also Documentation/scsi/st.txt.
1612 panic= [KNL] Kernel behaviour on panic
1615 parkbd.port= [HW] Parallel port number the keyboard adapter is
1616 connected to, default is 0.
1618 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1619 0 for XT, 1 for AT (default is AT).
1622 parport= [HW,PPT] Specify parallel ports. 0 disables.
1623 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1624 Use 'auto' to force the driver to use any
1625 IRQ/DMA settings detected (the default is to
1626 ignore detected IRQ/DMA settings because of
1627 possible conflicts). You can specify the base
1628 address, IRQ, and DMA settings; IRQ and DMA
1629 should be numbers, or 'auto' (for using detected
1630 settings on that particular port), or 'nofifo'
1631 (to avoid using a FIFO even if it is detected).
1632 Parallel ports are assigned in the order they
1633 are specified on the command line, starting
1636 parport_init_mode= [HW,PPT]
1637 Configure VIA parallel port to operate in
1638 a specific mode. This is necessary on Pegasos
1639 computer where firmware has no options for setting
1640 up parallel port mode and sets it to spp.
1641 Currently this function knows 686a and 8231 chips.
1642 Format: [spp|ps2|epp|ecp|ecpepp]
1644 pas2= [HW,OSS] Format:
1645 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1648 See header of drivers/scsi/pas16.c.
1651 Halt all CPUs after the first oops has been printed for
1652 the specified number of seconds. This is to be used if
1653 your oopses keep scrolling off the screen.
1658 See header of drivers/block/paride/pcd.c.
1659 See also Documentation/blockdev/paride.txt.
1661 pci=option[,option...] [PCI] various PCI subsystem options:
1662 off [X86] don't probe for the PCI bus
1663 bios [X86-32] force use of PCI BIOS, don't access
1664 the hardware directly. Use this if your machine
1665 has a non-standard PCI host bridge.
1666 nobios [X86-32] disallow use of PCI BIOS, only direct
1667 hardware access methods are allowed. Use this
1668 if you experience crashes upon bootup and you
1669 suspect they are caused by the BIOS.
1670 conf1 [X86] Force use of PCI Configuration
1672 conf2 [X86] Force use of PCI Configuration
1674 noaer [PCIE] If the PCIEAER kernel config parameter is
1675 enabled, this kernel boot option can be used to
1676 disable the use of PCIE advanced error reporting.
1677 nodomains [PCI] Disable support for multiple PCI
1678 root domains (aka PCI segments, in ACPI-speak).
1679 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1681 nomsi [MSI] If the PCI_MSI kernel config parameter is
1682 enabled, this kernel boot option can be used to
1683 disable the use of MSI interrupts system-wide.
1684 noioapicquirk [APIC] Disable all boot interrupt quirks.
1685 Safety option to keep boot IRQs enabled. This
1686 should never be necessary.
1687 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1688 primary IO-APIC for bridges that cannot disable
1689 boot IRQs. This fixes a source of spurious IRQs
1690 when the system masks IRQs.
1691 noioapicreroute [APIC] Disable workaround that uses the
1692 boot IRQ equivalent of an IRQ that connects to
1693 a chipset where boot IRQs cannot be disabled.
1694 The opposite of ioapicreroute.
1695 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1696 routing table. These calls are known to be buggy
1697 on several machines and they hang the machine
1698 when used, but on other computers it's the only
1699 way to get the interrupt routing table. Try
1700 this option if the kernel is unable to allocate
1701 IRQs or discover secondary PCI buses on your
1703 rom [X86] Assign address space to expansion ROMs.
1704 Use with caution as certain devices share
1705 address decoders between ROMs and other
1707 norom [X86] Do not assign address space to
1708 expansion ROMs that do not already have
1709 BIOS assigned address ranges.
1710 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1711 assigned automatically to PCI devices. You can
1712 make the kernel exclude IRQs of your ISA cards
1714 pirqaddr=0xAAAAA [X86] Specify the physical address
1715 of the PIRQ table (normally generated
1716 by the BIOS) if it is outside the
1717 F0000h-100000h range.
1718 lastbus=N [X86] Scan all buses thru bus #N. Can be
1719 useful if the kernel is unable to find your
1720 secondary buses and you want to tell it
1721 explicitly which ones they are.
1722 assign-busses [X86] Always assign all PCI bus
1723 numbers ourselves, overriding
1724 whatever the firmware may have done.
1725 usepirqmask [X86] Honor the possible IRQ mask stored
1726 in the BIOS $PIR table. This is needed on
1727 some systems with broken BIOSes, notably
1728 some HP Pavilion N5400 and Omnibook XE3
1729 notebooks. This will have no effect if ACPI
1730 IRQ routing is enabled.
1731 noacpi [X86] Do not use ACPI for IRQ routing
1732 or for PCI scanning.
1733 use_crs [X86] Use _CRS for PCI resource
1735 routeirq Do IRQ routing for all PCI devices.
1736 This is normally done in pci_enable_device(),
1737 so this option is a temporary workaround
1738 for broken drivers that don't call it.
1739 skip_isa_align [X86] do not align io start addr, so can
1740 handle more pci cards
1741 firmware [ARM] Do not re-enumerate the bus but instead
1742 just use the configuration from the
1743 bootloader. This is currently used on
1744 IXP2000 systems where the bus has to be
1745 configured a certain way for adjunct CPUs.
1746 noearly [X86] Don't do any early type 1 scanning.
1747 This might help on some broken boards which
1748 machine check when some devices' config space
1749 is read. But various workarounds are disabled
1750 and some IOMMU drivers will not work.
1751 bfsort Sort PCI devices into breadth-first order.
1752 This sorting is done to get a device
1753 order compatible with older (<= 2.4) kernels.
1754 nobfsort Don't sort PCI devices into breadth-first order.
1755 cbiosize=nn[KMG] The fixed amount of bus space which is
1756 reserved for the CardBus bridge's IO window.
1757 The default value is 256 bytes.
1758 cbmemsize=nn[KMG] The fixed amount of bus space which is
1759 reserved for the CardBus bridge's memory
1760 window. The default value is 64 megabytes.
1762 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1765 force Enable ASPM even on devices that claim not to support it.
1766 WARNING: Forcing ASPM on may cause system lockups.
1768 pcmv= [HW,PCMCIA] BadgePAD 4
1771 See Documentation/blockdev/paride.txt.
1773 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1776 See arch/parisc/kernel/pdc_chassis.c
1779 See Documentation/blockdev/paride.txt.
1782 See Documentation/blockdev/paride.txt.
1784 pirq= [SMP,APIC] Manual mp-table setup
1785 See Documentation/x86/i386/IO-APIC.txt.
1787 plip= [PPT,NET] Parallel port network link
1788 Format: { parport<nr> | timid | 0 }
1789 See also Documentation/parport.txt.
1791 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1792 Override pmtimer IOPort with a hex value.
1796 Enable PNP debug messages. This depends on the
1797 CONFIG_PNP_DEBUG_MESSAGES option.
1803 { on | off | curr | res | no-curr | no-res }
1806 [ISAPNP] Exclude IRQs for the autoconfiguration
1809 [ISAPNP] Exclude DMAs for the autoconfiguration
1811 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1812 Ranges are in pairs (I/O port base and size).
1815 [ISAPNP] Exclude memory regions for the
1817 Ranges are in pairs (memory base and size).
1819 dynamic_printk Enables pr_debug()/dev_dbg() calls if
1820 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
1821 These can also be switched on/off via
1822 <debugfs>/dynamic_printk/modules
1824 print-fatal-signals=
1825 [KNL] debug: print fatal signals
1826 print-fatal-signals=1: print segfault info to
1830 printk.time= Show timing data prefixed to each printk message line
1831 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1833 profile= [KNL] Enable kernel profiling via /proc/profile
1834 Format: [schedule,]<number>
1835 Param: "schedule" - profile schedule points.
1836 Param: <number> - step/bucket size as a power of 2 for
1837 statistical time based profiling.
1838 Param: "sleep" - profile D-state sleeping (millisecs).
1839 Requires CONFIG_SCHEDSTATS
1840 Param: "kvm" - profile VM exits.
1842 processor.max_cstate= [HW,ACPI]
1843 Limit processor to maximum C-state
1844 max_cstate=9 overrides any DMI blacklist limit.
1846 processor.nocst [HW,ACPI]
1847 Ignore the _CST method to determine C-states,
1848 instead using the legacy FADT method
1850 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1852 See Documentation/blockdev/ramdisk.txt.
1854 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1855 probe for; one of (bare|imps|exps|lifebook|any).
1856 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1858 psmouse.resetafter= [HW,MOUSE]
1859 Try to reset the device after so many bad packets
1862 [HW,MOUSE] Set desired mouse resolution, in dpi.
1863 psmouse.smartscroll=
1864 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1865 0 = disabled, 1 = enabled (default).
1867 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1869 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1872 See Documentation/blockdev/paride.txt.
1875 [KNL] Number of legacy pty's. Overwrites compiled-in
1878 quiet [KNL] Disable most log messages
1883 See Documentation/md.txt.
1885 ramdisk_blocksize= [RAM]
1886 See Documentation/blockdev/ramdisk.txt.
1888 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1889 See Documentation/blockdev/ramdisk.txt.
1891 rcupdate.blimit= [KNL,BOOT]
1892 Set maximum number of finished RCU callbacks to process
1895 rcupdate.qhimark= [KNL,BOOT]
1896 Set threshold of queued
1897 RCU callbacks over which batch limiting is disabled.
1899 rcupdate.qlowmark= [KNL,BOOT]
1900 Set threshold of queued RCU callbacks below which
1901 batch limiting is re-enabled.
1905 Run specified binary instead of /init from the ramdisk,
1906 used for early userspace startup. See initrd.
1908 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1909 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1910 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1913 [KNL, SMP] Set scheduler's default relax_domain_level.
1914 See Documentation/cpusets.txt.
1916 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1918 reservetop= [X86-32]
1920 Reserves a hole at the top of the kernel virtual
1923 reset_devices [KNL] Force drivers to reset the underlying device
1924 during initialization.
1927 Specify the partition device for software suspend
1929 resume_offset= [SWSUSP]
1930 Specify the offset from the beginning of the partition
1931 given by "resume=" at which the swap header is located,
1932 in <PAGE_SIZE> units (needed only for swap files).
1933 See Documentation/power/swsusp-and-swap-files.txt
1935 retain_initrd [RAM] Keep initrd memory after extraction
1937 rhash_entries= [KNL,NET]
1938 Set number of hash buckets for route cache
1940 riscom8= [HW,SERIAL]
1941 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1943 ro [KNL] Mount root device read-only on boot
1945 root= [KNL] Root filesystem
1947 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1948 mount the root filesystem
1950 rootflags= [KNL] Set root filesystem mount option string
1952 rootfstype= [KNL] Set root filesystem type
1954 rootwait [KNL] Wait (indefinitely) for root device to show up.
1955 Useful for devices that are detected asynchronously
1956 (e.g. USB and MMC devices).
1958 root_plug.vendor_id=
1959 [ROOTPLUG] Override the default vendor ID
1961 root_plug.product_id=
1962 [ROOTPLUG] Override the default product ID
1965 [ROOTPLUG] Enable debugging output
1967 rw [KNL] Mount root device read-write on boot
1969 S [KNL] Run init in single mode
1972 See drivers/net/irda/sa1100_ir.c.
1974 sbni= [NET] Granch SBNI12 leased line adapter
1976 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1977 Format: <io>[,<timeout>[,<isapnp>]]
1979 scsi_debug_*= [SCSI]
1980 See drivers/scsi/scsi_debug.c.
1982 scsi_default_dev_flags=
1983 [SCSI] SCSI default device flags
1986 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1987 Format: <vendor>:<model>:<flags>
1988 (flags are integer value)
1990 scsi_logging_level= [SCSI] a bit mask of logging levels
1991 See drivers/scsi/scsi_logging.h for bits. Also
1992 settable via sysctl at dev.scsi.logging_level
1993 (/proc/sys/dev/scsi/logging_level).
1994 There is also a nice 'scsi_logging_level' script in the
1995 S390-tools package, available for download at
1996 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1998 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1999 discovered. async scans them in kernel threads,
2000 allowing boot to proceed. none ignores them, expecting
2001 user space to do the scan.
2003 selinux [SELINUX] Disable or enable SELinux at boot time.
2004 Format: { "0" | "1" }
2005 See security/selinux/Kconfig help text.
2008 Default value is set via kernel config option.
2009 If enabled at boot time, /selinux/disable can be used
2010 later to disable prior to initial policy load.
2012 selinux_compat_net =
2013 [SELINUX] Set initial selinux_compat_net flag value.
2014 Format: { "0" | "1" }
2015 0 -- use new secmark-based packet controls
2016 1 -- use legacy packet controls
2017 Default value is 0 (preferred).
2018 Value can be changed at runtime via
2019 /selinux/compat_net.
2021 serialnumber [BUGS=X86-32]
2024 Maximal number of shapers.
2026 show_msr= [x86] show boot-time MSR settings
2027 Format: { <integer> }
2028 Show boot-time (BIOS-initialized) MSR settings.
2029 The parameter means the number of CPUs to show,
2030 for example 1 means boot CPU only.
2033 See header of drivers/scsi/sim710.c.
2040 slub_debug[=options[,slabs]] [MM, SLUB]
2041 Enabling slub_debug allows one to determine the
2042 culprit if slab objects become corrupted. Enabling
2043 slub_debug can create guard zones around objects and
2044 may poison objects when not in use. Also tracks the
2045 last alloc / free. For more information see
2046 Documentation/vm/slub.txt.
2048 slub_max_order= [MM, SLUB]
2049 Determines the maximum allowed order for slabs.
2050 A high setting may cause OOMs due to memory
2051 fragmentation. For more information see
2052 Documentation/vm/slub.txt.
2054 slub_min_objects= [MM, SLUB]
2055 The minimum number of objects per slab. SLUB will
2056 increase the slab order up to slub_max_order to
2057 generate a sufficiently large slab able to contain
2058 the number of objects indicated. The higher the number
2059 of objects the smaller the overhead of tracking slabs
2060 and the less frequently locks need to be acquired.
2061 For more information see Documentation/vm/slub.txt.
2063 slub_min_order= [MM, SLUB]
2064 Determines the mininum page order for slabs. Must be
2065 lower than slub_max_order.
2066 For more information see Documentation/vm/slub.txt.
2068 slub_nomerge [MM, SLUB]
2069 Disable merging of slabs with similar size. May be
2070 necessary if there is some reason to distinguish
2071 allocs to different slabs. Debug options disable
2072 merging on their own.
2073 For more information see Documentation/vm/slub.txt.
2076 Format: <io1>[,<io2>[,...,<io8>]]
2078 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2079 attempt to substitute SMP alternatives once at boot.
2081 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2082 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2083 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2084 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2085 smsc-ircc2.ircc_irq= [HW] IRQ line
2086 smsc-ircc2.ircc_dma= [HW] DMA channel
2087 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2088 0: Toshiba Satellite 1800 (GP data pin select)
2089 1: Fast pin select (default)
2092 snd-ad1816a= [HW,ALSA]
2094 snd-ad1848= [HW,ALSA]
2096 snd-ali5451= [HW,ALSA]
2098 snd-als100= [HW,ALSA]
2100 snd-als4000= [HW,ALSA]
2102 snd-azt2320= [HW,ALSA]
2104 snd-cmi8330= [HW,ALSA]
2106 snd-cmipci= [HW,ALSA]
2108 snd-cs4231= [HW,ALSA]
2110 snd-cs4232= [HW,ALSA]
2112 snd-cs4236= [HW,ALSA]
2114 snd-cs4281= [HW,ALSA]
2116 snd-cs46xx= [HW,ALSA]
2118 snd-dt019x= [HW,ALSA]
2120 snd-dummy= [HW,ALSA]
2122 snd-emu10k1= [HW,ALSA]
2124 snd-ens1370= [HW,ALSA]
2126 snd-ens1371= [HW,ALSA]
2128 snd-es968= [HW,ALSA]
2130 snd-es1688= [HW,ALSA]
2132 snd-es18xx= [HW,ALSA]
2134 snd-es1938= [HW,ALSA]
2136 snd-es1968= [HW,ALSA]
2138 snd-fm801= [HW,ALSA]
2140 snd-gusclassic= [HW,ALSA]
2142 snd-gusextreme= [HW,ALSA]
2144 snd-gusmax= [HW,ALSA]
2148 snd-ice1712= [HW,ALSA]
2150 snd-intel8x0= [HW,ALSA]
2152 snd-interwave= [HW,ALSA]
2157 snd-korg1212= [HW,ALSA]
2159 snd-maestro3= [HW,ALSA]
2161 snd-mpu401= [HW,ALSA]
2163 snd-mtpav= [HW,ALSA]
2165 snd-nm256= [HW,ALSA]
2167 snd-opl3sa2= [HW,ALSA]
2175 snd-opti93x= [HW,ALSA]
2179 snd-rme32= [HW,ALSA]
2181 snd-rme96= [HW,ALSA]
2183 snd-rme9652= [HW,ALSA]
2189 snd-sbawe= [HW,ALSA]
2191 snd-serial= [HW,ALSA]
2193 snd-sgalaxy= [HW,ALSA]
2195 snd-sonicvibes= [HW,ALSA]
2200 snd-sun-cs4231= [HW,ALSA]
2202 snd-trident= [HW,ALSA]
2204 snd-usb-audio= [HW,ALSA,USB]
2206 snd-via82xx= [HW,ALSA]
2208 snd-virmidi= [HW,ALSA]
2210 snd-wavefront= [HW,ALSA]
2212 snd-ymfpci= [HW,ALSA]
2215 [KNL] Should the soft-lockup detector generate panics.
2217 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2218 See Documentation/sonypi.txt
2220 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2221 See Documentation/serial/specialix.txt.
2223 spia_io_base= [HW,MTD]
2229 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2231 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2232 See Documentation/scsi/st.txt.
2235 Enabled the stack tracer on boot up.
2239 Set the STI (builtin display/keyboard on the HP-PARISC
2240 machines) console (graphic card) which should be used
2241 as the initial boot-console.
2242 See also comment in drivers/video/console/sticore.c.
2245 See comment in drivers/video/console/sticore.c.
2248 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2252 Control how the NFS server code allocates CPUs to
2253 service thread pools. Depending on how many NICs
2254 you have and where their interrupts are bound, this
2255 option will affect which CPUs will do NFS serving.
2256 Note: this parameter cannot be changed while the
2257 NFS server is running.
2259 auto the server chooses an appropriate mode
2260 automatically using heuristics
2261 global a single global pool contains all CPUs
2262 percpu one pool for each CPU
2263 pernode one pool for each NUMA node (equivalent
2264 to global on non-NUMA machines)
2266 swiotlb= [IA-64] Number of I/O TLB slabs
2270 sym53c416= [HW,SCSI]
2271 See header of drivers/scsi/sym53c416.c.
2273 sysrq_always_enabled
2275 Ignore sysrq setting - this boot parameter will
2276 neutralize any effect of /proc/sys/kernel/sysrq.
2277 Useful for debugging.
2280 See header of drivers/scsi/t128.c.
2284 test_suspend= [SUSPEND]
2285 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2286 standby suspend) as the system sleep state to briefly
2287 enter during system startup. The system is woken from
2288 this state using a wakeup-capable RTC alarm.
2290 thash_entries= [KNL,NET]
2291 Set number of hash buckets for TCP connection
2293 thermal.act= [HW,ACPI]
2294 -1: disable all active trip points in all thermal zones
2295 <degrees C>: override all lowest active trip points
2297 thermal.crt= [HW,ACPI]
2298 -1: disable all critical trip points in all thermal zones
2299 <degrees C>: override all critical trip points
2301 thermal.nocrt= [HW,ACPI]
2302 Set to disable actions on ACPI thermal zone
2303 critical and hot trip points.
2305 thermal.off= [HW,ACPI]
2306 1: disable ACPI thermal control
2308 thermal.psv= [HW,ACPI]
2309 -1: disable all passive trip points
2310 <degrees C>: override all passive trip points to this
2313 thermal.tzp= [HW,ACPI]
2314 Specify global default ACPI thermal zone polling rate
2315 <deci-seconds>: poll all this frequency
2316 0: no polling (default)
2319 See comment before function dc390_setup() in
2320 drivers/scsi/tmscsim.c.
2324 Specify if the kernel should make use of the cpu
2325 topology informations if the hardware supports these.
2326 The scheduler will make use of these informations and
2327 e.g. base its process migration decisions on it.
2332 trix= [HW,OSS] MediaTrix AudioTrix Pro
2334 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2336 tsc= Disable clocksource-must-verify flag for TSC.
2338 [x86] reliable: mark tsc clocksource as reliable, this
2339 disables clocksource verification at runtime.
2340 Used to enable high-resolution timer mode on older
2341 hardware, and in virtualized environment.
2343 turbografx.map[2|3]= [HW,JOY]
2344 TurboGraFX parallel port interface
2346 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2347 See also Documentation/input/joystick-parport.txt
2349 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2350 See header of drivers/scsi/u14-34f.c.
2359 [USB] Ignore overcurrent events (default N).
2360 Some badly-designed motherboards generate lots of
2361 bogus events, for ports that aren't wired to
2362 anything. Set this parameter to avoid log spamming.
2363 Note that genuine overcurrent events won't be
2368 Set unknown_nmi_panic=1 early on boot.
2370 usbcore.autosuspend=
2371 [USB] The autosuspend time delay (in seconds) used
2372 for newly-detected USB devices (default 2). This
2373 is the time required before an idle device will be
2374 autosuspended. Devices for which the delay is set
2375 to a negative value won't be autosuspended at all.
2377 usbcore.usbfs_snoop=
2378 [USB] Set to log all usbfs traffic (default 0 = off).
2380 usbcore.blinkenlights=
2381 [USB] Set to cycle leds on hubs (default 0 = off).
2383 usbcore.old_scheme_first=
2384 [USB] Start with the old device initialization
2385 scheme (default 0 = off).
2387 usbcore.use_both_schemes=
2388 [USB] Try the other device initialization scheme
2389 if the first one fails (default 1 = enabled).
2391 usbcore.initial_descriptor_timeout=
2392 [USB] Specifies timeout for the initial 64-byte
2393 USB_REQ_GET_DESCRIPTOR request in milliseconds
2394 (default 5000 = 5.0 seconds).
2397 [USBHID] The interval which mice are to be polled at.
2399 usb-storage.delay_use=
2400 [UMS] The delay in seconds before a new device is
2401 scanned for Logical Units (default 5).
2404 [UMS] A list of quirks entries to supplement or
2405 override the built-in unusual_devs list. List
2406 entries are separated by commas. Each entry has
2407 the form VID:PID:Flags where VID and PID are Vendor
2408 and Product ID values (4-digit hex numbers) and
2409 Flags is a set of characters, each corresponding
2410 to a common usb-storage quirk flag as follows:
2411 a = SANE_SENSE (collect more than 18 bytes
2413 c = FIX_CAPACITY (decrease the reported
2414 device capacity by one sector);
2415 h = CAPACITY_HEURISTICS (decrease the
2416 reported device capacity by one
2417 sector if the number is odd);
2418 i = IGNORE_DEVICE (don't bind to this
2420 l = NOT_LOCKABLE (don't try to lock and
2421 unlock ejectable media);
2422 m = MAX_SECTORS_64 (don't transfer more
2423 than 64 sectors = 32 KB at a time);
2424 o = CAPACITY_OK (accept the capacity
2425 reported by the device);
2426 r = IGNORE_RESIDUE (the device reports
2427 bogus residue values);
2428 s = SINGLE_LUN (the device has only one
2430 w = NO_WP_DETECT (don't test whether the
2431 medium is write-protected).
2432 Example: quirks=0419:aaf5:rl,0421:0433:rc
2434 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2435 kernel's map of available physical RAM.
2437 vdso= [X86-32,SH,x86-64]
2438 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2439 vdso=1: enable VDSO (default)
2440 vdso=0: disable VDSO mapping
2442 vdso32= [X86-32,X86-64]
2443 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2444 vdso32=1: enable 32-bit VDSO (default)
2445 vdso32=0: disable 32-bit VDSO mapping
2448 vector=percpu: enable percpu vector domain
2450 video= [FB] Frame buffer configuration
2451 See Documentation/fb/modedb.txt.
2453 vga= [BOOT,X86-32] Select a particular video mode
2454 See Documentation/x86/boot.txt and
2455 Documentation/svga.txt.
2456 Use vga=ask for menu.
2457 This is actually a boot loader parameter; the value is
2458 passed to the kernel using a special protocol.
2460 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2461 size of <nn>. This can be used to increase the
2462 minimum size (128MB on x86). It can also be used to
2463 decrease the size and leave more room for directly
2466 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2469 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2472 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2475 waveartist= [HW,OSS]
2476 Format: <io>,<irq>,<dma>,<dma2>
2479 See header of drivers/scsi/wd33c93.c.
2482 See header of drivers/scsi/wd7000.c.
2485 See Documentation/watchdog/wdt.txt.
2487 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2488 xd_geo= See header of drivers/block/xd.c.
2490 xirc2ps_cs= [NET,PCMCIA]
2492 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2494 norandmaps Don't use address space randomization. Equivalent to
2495 echo 0 > /proc/sys/kernel/randomize_va_space
2497 ______________________________________________________________________
2501 Add documentation for ALSA options.
2502 Add more DRM drivers.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob