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/x86_64/boot-options.txt .
104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
106 In addition, the following text indicates that the option:
108 BUGS= Relates to possible processor bugs on the said processor.
109 KNL Is a kernel start-up parameter.
110 BOOT Is a boot loader parameter.
112 Parameters denoted with BOOT are actually interpreted by the boot
113 loader, and have no meaning to the kernel directly.
114 Do not modify the syntax of boot loader parameters without extreme
115 need or coordination with <Documentation/x86/i386/boot.txt>.
117 There are also arch-specific kernel-parameters not documented here.
118 See for example <Documentation/x86/x86_64/boot-options.txt>.
120 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
121 a trailing = on the name of any parameter states that that parameter will
122 be entered as an environment variable, whereas its absence indicates that
123 it will appear as a kernel argument readable via /proc/cmdline by programs
124 running once the system is up.
126 The number of kernel parameters is not limited, but the length of the
127 complete command line (parameters including spaces etc.) is limited to
128 a fixed number of characters. This limit depends on the architecture
129 and is between 256 and 4096 characters. It is defined in the file
130 ./include/asm/setup.h as COMMAND_LINE_SIZE.
133 acpi= [HW,ACPI,X86-64,i386]
134 Advanced Configuration and Power Interface
135 Format: { force | off | ht | strict | noirq }
136 force -- enable ACPI if default was off
137 off -- disable ACPI if default was on
138 noirq -- do not use ACPI for IRQ routing
139 ht -- run only enough ACPI to enable Hyper Threading
140 strict -- Be less tolerant of platforms that are not
141 strictly ACPI specification compliant.
143 See also Documentation/power/pm.txt, pci=noacpi
145 acpi_apic_instance= [ACPI, IOAPIC]
147 2: use 2nd APIC table, if available
148 1,0: use 1st APIC table
151 acpi_sleep= [HW,ACPI] Sleep options
152 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
153 See Documentation/power/video.txt for s3_bios and s3_mode.
154 s3_beep is for debugging; it makes the PC's speaker beep
155 as soon as the kernel's real-mode entry point is called.
156 s4_nohwsig prevents ACPI hardware signature from being
157 used during resume from hibernation.
158 old_ordering causes the ACPI 1.0 ordering of the _PTS
159 control method, wrt putting devices into low power
160 states, to be enforced (the ACPI 2.0 ordering of _PTS is
163 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
164 Format: { level | edge | high | low }
166 acpi_irq_balance [HW,ACPI]
167 ACPI will balance active IRQs
170 acpi_irq_nobalance [HW,ACPI]
171 ACPI will not move active IRQs (default)
174 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
176 Format: <irq>,<irq>...
178 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
179 Format: <irq>,<irq>...
181 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
183 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
184 Format: To spoof as Windows 98: ="Microsoft Windows"
186 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
187 acpi_osi="string1" # add string1 -- only one string
188 acpi_osi="!string2" # remove built-in string2
189 acpi_osi= # disable all strings
191 acpi_serialize [HW,ACPI] force serialization of AML methods
193 acpi_skip_timer_override [HW,ACPI]
194 Recognize and ignore IRQ0/pin2 Interrupt Override.
195 For broken nForce2 BIOS resulting in XT-PIC timer.
196 acpi_use_timer_override [HW,ACPI}
197 Use timer override. For some broken Nvidia NF5 boards
198 that require a timer override, but don't have
201 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
202 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
204 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
205 debug output. Bits in debug_layer correspond to a
206 _COMPONENT in an ACPI source file, e.g.,
207 #define _COMPONENT ACPI_PCI_COMPONENT
208 Bits in debug_level correspond to a level in
209 ACPI_DEBUG_PRINT statements, e.g.,
210 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
211 See Documentation/acpi/debug.txt for more information
212 about debug layers and levels.
214 Enable AML "Debug" output, i.e., stores to the Debug
215 object while interpreting AML:
216 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
217 Enable PCI/PCI interrupt routing info messages:
218 acpi.debug_layer=0x400000 acpi.debug_level=0x4
219 Enable all messages related to ACPI hardware:
220 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
222 Some values produce so much output that the system is
223 unusable. The "log_buf_len" parameter may be useful
224 if you need to capture more output.
226 acpi.power_nocheck= [HW,ACPI]
227 Format: 1/0 enable/disable the check of power state.
228 On some bogus BIOS the _PSC object/_STA object of
229 power resource can't return the correct device power
230 state. In such case it is unneccessary to check its
231 power state again in power transition.
232 1 : disable the power state check
234 acpi_pm_good [X86-32,X86-64]
235 Override the pmtimer bug detection: force the kernel
236 to assume that this machine's pmtimer latches its value
237 and always returns good values.
240 { off | try_unsupported }
241 off: disable AGP support
242 try_unsupported: try to drive unsupported chipsets
243 (may crash computer or cause data corruption)
245 enable_timer_pin_1 [i386,x86-64]
246 Enable PIN 1 of APIC timer
247 Can be useful to work around chipset bugs
248 (in particular on some ATI chipsets).
249 The kernel tries to set a reasonable default.
251 disable_timer_pin_1 [i386,x86-64]
252 Disable PIN 1 of APIC timer
253 Can be useful to work around chipset bugs.
256 Format: <io>,<irq>,<dma>,<dma2>,<type>
259 See header of drivers/scsi/advansys.c.
261 advwdt= [HW,WDT] Advantech WDT
262 Format: <iostart>,<iostop>
264 aedsp16= [HW,OSS] Audio Excel DSP 16
265 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
266 See also header of sound/oss/aedsp16.c.
269 See Documentation/scsi/aha152x.txt.
272 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
275 See Documentation/scsi/aic7xxx.txt.
278 See Documentation/scsi/aic79xx.txt.
280 amd_iommu= [HW,X86-84]
281 Pass parameters to the AMD IOMMU driver in the system.
283 isolate - enable device isolation (each device, as far
284 as possible, will get its own protection
286 fullflush - enable flushing of IO/TLB entries when
287 they are unmapped. Otherwise they are
288 flushed before they will be reused, which
291 amd_iommu_size= [HW,X86-64]
292 Define the size of the aperture for the AMD IOMMU
293 driver. Possible values are:
294 '32M', '64M' (default), '128M', '256M', '512M', '1G'
296 amijoy.map= [HW,JOY] Amiga joystick support
297 Map of devices attached to JOY0DAT and JOY1DAT
299 See also Documentation/kernel/input/joystick.txt
301 analog.map= [HW,JOY] Analog joystick and gamepad support
302 Specifies type or capabilities of an analog joystick
303 connected to one of 16 gameports
304 Format: <type1>,<type2>,..<type16>
307 Power management functions (SPARCstation-4/5 + deriv.)
309 Disable APC CPU standby support. SPARCstation-Fox does
310 not play well with APC CPU idle - disable it if you have
311 APC and your system crashes randomly.
313 apic= [APIC,i386] Advanced Programmable Interrupt Controller
314 Change the output verbosity whilst booting
315 Format: { quiet (default) | verbose | debug }
316 Change the amount of debugging information output
317 when initialising the APIC and IO-APIC components.
319 apm= [APM] Advanced Power Management
320 See header of arch/x86/kernel/apm_32.c.
322 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
323 Format: <io>,<irq>,<nodeID>
327 atarimouse= [HW,MOUSE] Atari Mouse
329 atascsi= [HW,SCSI] Atari SCSI
331 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
332 EzKey and similar keyboards
334 atkbd.reset= [HW] Reset keyboard during initialization
336 atkbd.set= [HW] Select keyboard code set
337 Format: <int> (2 = AT (default), 3 = PS/2)
339 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
342 atkbd.softraw= [HW] Choose between synthetic and real raw mode
343 Format: <bool> (0 = real, 1 = synthetic (default))
345 atkbd.softrepeat= [HW]
346 Use software keyboard repeat
350 baycom_epp= [HW,AX25]
353 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
355 See header of drivers/net/hamradio/baycom_par.c.
357 baycom_ser_fdx= [HW,AX25]
358 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
359 Format: <io>,<irq>,<mode>[,<baud>]
360 See header of drivers/net/hamradio/baycom_ser_fdx.c.
362 baycom_ser_hdx= [HW,AX25]
363 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
364 Format: <io>,<irq>,<mode>
365 See header of drivers/net/hamradio/baycom_ser_hdx.c.
367 boot_delay= Milliseconds to delay each printk during boot.
368 Values larger than 10 seconds (10000) are changed to
372 bootmem_debug [KNL] Enable bootmem allocator debug messages.
374 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
375 bttv.radio= Most important insmod options are available as
377 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
378 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
381 See drivers/scsi/BusLogic.c, comment before function
382 BusLogic_ParseDriverOptions().
384 c101= [NET] Moxa C101 synchronous serial card
386 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
387 Sometimes CPU hardware bugs make them report the cache
388 size incorrectly. The kernel will attempt work arounds
389 to fix known problems, but for some CPUs it is not
390 possible to determine what the correct size should be.
391 This option provides an override for these situations.
393 security= [SECURITY] Choose a security module to enable at boot.
394 If this boot parameter is not specified, only the first
395 security module asking for security registration will be
396 loaded. An invalid security module name will be treated
397 as if no module has been chosen.
400 [SECURITY] Disable capabilities. This would normally
401 be used only if an alternative security model is to be
402 configured. Potentially dangerous and should only be
403 used if you are entirely sure of the consequences.
405 ccw_timeout_log [S390]
406 See Documentation/s390/CommonIO for details.
408 cgroup_disable= [KNL] Disable a particular controller
409 Format: {name of the controller(s) to disable}
410 {Currently supported controllers - "memory"}
412 checkreqprot [SELINUX] Set initial checkreqprot flag value.
413 Format: { "0" | "1" }
414 See security/selinux/Kconfig help text.
415 0 -- check protection applied by kernel (includes
416 any implied execute protection).
417 1 -- check protection requested by application.
418 Default value is set via a kernel config option.
419 Value can be changed at runtime via
420 /selinux/checkreqprot.
423 See Documentation/s390/CommonIO for details.
425 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
427 Forces specified clocksource (if available) to be used
428 when calculating gettimeofday(). If specified
429 clocksource is not available, it defaults to PIT.
430 Format: { pit | tsc | cyclone | pmtmr }
432 clocksource= [GENERIC_TIME] Override the default clocksource
434 Override the default clocksource and use the clocksource
435 with the name specified.
436 Some clocksource names to choose from, depending on
438 [all] jiffies (this is the base, fallback clocksource)
440 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
441 pxa_timer,timer3,32k_counter,timer0_1
443 [X86-32] pit,hpet,tsc,vmi-timer;
444 scx200_hrt on Geode; cyclone on IBM x440
452 clearcpuid=BITNUM [X86]
453 Disable CPUID feature X for the kernel. See
454 include/asm-x86/cpufeature.h for the valid bit numbers.
455 Note the Linux specific bits are not necessarily
456 stable over kernel options, but the vendor specific
458 Also note that user programs calling CPUID directly
459 or using the feature without checking anything
460 will still see it. This just prevents it from
461 being used by the kernel or shown in /proc/cpuinfo.
462 Also note the kernel might malfunction if you disable
465 code_bytes [IA32/X86_64] How many bytes of object code to print
470 hpet= [X86-32,HPET] option to control HPET usage
471 Format: { enable (default) | disable | force }
472 disable: disable HPET and use PIT instead
473 force: allow force enabled of undocumented chips (ICH4,
476 com20020= [HW,NET] ARCnet - COM20020 chipset
478 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
480 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
484 ARCnet - COM90xx chipset (memory-mapped buffers)
485 Format: <io>[,<irq>[,<memstart>]]
487 condev= [HW,S390] console device
490 console= [KNL] Output console device and options.
492 tty<n> Use the virtual console device <n>.
496 Use the specified serial port. The options are of
497 the form "bbbbpnf", where "bbbb" is the baud rate,
498 "p" is parity ("n", "o", or "e"), "n" is number of
499 bits, and "f" is flow control ("r" for RTS or
500 omit it). Default is "9600n8".
502 See Documentation/serial-console.txt for more
504 Documentation/networking/netconsole.txt for an
507 uart[8250],io,<addr>[,options]
508 uart[8250],mmio,<addr>[,options]
509 Start an early, polled-mode console on the 8250/16550
510 UART at the specified I/O port or MMIO address,
511 switching to the matching ttyS device later. The
512 options are the same as for ttyS, above.
514 If the device connected to the port is not a TTY but a braille
515 device, prepend "brl," before the device type, for instance
517 For now, only VisioBraille is supported.
519 earlycon= [KNL] Output early console device and options.
520 uart[8250],io,<addr>[,options]
521 uart[8250],mmio,<addr>[,options]
522 Start an early, polled-mode console on the 8250/16550
523 UART at the specified I/O port or MMIO address.
524 The options are the same as for ttyS, above.
527 [HW] Never suspend the console
528 Disable suspending of consoles during suspend and
529 hibernate operations. Once disabled, debugging
530 messages can reach various consoles while the rest
531 of the system is being put to sleep (ie, while
532 debugging driver suspend/resume hooks). This may
533 not work reliably with all consoles, but is known
534 to work with serial and VGA consoles.
536 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
538 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
540 crashkernel=nn[KMG]@ss[KMG]
541 [KNL] Reserve a chunk of physical memory to
542 hold a kernel to switch to with kexec on panic.
544 crashkernel=range1:size1[,range2:size2,...][@offset]
545 [KNL] Same as above, but depends on the memory
546 in the running system. The syntax of range is
547 start-[end] where start and end are both
548 a memory unit (amount[KMG]). See also
549 Documentation/kdump/kdump.txt for a example.
552 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
557 cs89x0_media= [HW,NET]
558 Format: { rj45 | aui | bnc }
561 See header of drivers/s390/block/dasd_devmap.c.
563 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
564 (one device per port)
565 Format: <port#>,<type>
566 See also Documentation/input/joystick-parport.txt
568 debug [KNL] Enable kernel debugging (events log level).
571 [KNL] verbose self-tests
573 Print debugging info while doing the locking API
575 We default to 0 (no extra messages), setting it to
576 1 will print _a lot_ more information - normally
577 only useful to kernel developers.
579 debug_objects [KNL] Enable object debugging
581 debugpat [X86] Enable PAT debugging
583 decnet.addr= [HW,NET]
584 Format: <area>[,<node>]
585 See also Documentation/networking/decnet.txt.
588 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
589 Change the default blue palette of the console.
590 This is a 16-member array composed of values
594 Format: <green0>,<green1>,<green2>,...,<green15>
595 Change the default green palette of the console.
596 This is a 16-member array composed of values
600 Format: <red0>,<red1>,<red2>,...,<red15>
601 Change the default red palette of the console.
602 This is a 16-member array composed of values
608 Set system-wide default UTF-8 mode for all tty's.
609 Default is 1, i.e. UTF-8 mode is enabled for all
610 newly opened terminals.
613 Set number of hash buckets for dentry cache.
616 IO parameters + enable/disable command.
618 digiepca= [HW,SERIAL]
619 See drivers/char/README.epca and
620 Documentation/digiepca.txt.
622 disable_mtrr_cleanup [X86]
623 enable_mtrr_cleanup [X86]
624 The kernel tries to adjust MTRR layout from continuous
625 to discrete, to make X server driver able to add WB
626 entry later. This parameter enables/disables that.
628 mtrr_chunk_size=nn[KMG] [X86]
629 used for mtrr cleanup. It is largest continous chunk
630 that could hold holes aka. UC entries.
632 mtrr_gran_size=nn[KMG] [X86]
633 Used for mtrr cleanup. It is granularity of mtrr block.
635 Large value could prevent small alignment from
638 mtrr_spare_reg_nr=n [X86]
640 Range: 0,7 : spare reg number
642 Used for mtrr cleanup. It is spare mtrr entries number.
643 Set to 2 or more if your graphical card needs more.
645 disable_mtrr_trim [X86, Intel and AMD only]
646 By default the kernel will trim any uncacheable
647 memory out of your available memory pool based on
648 MTRR settings. This parameter disables that behavior,
649 possibly causing your machine to run very slowly.
651 dmasound= [HW,OSS] Sound subsystem buffers
657 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
659 earlyprintk=serial[,ttySn[,baudrate]]
662 Append ",keep" to not disable it when the real console
665 Only vga or serial or usb debug port at a time.
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= [IA64,PPC,SH,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
800 i8042.debug [HW] Toggle i8042 debug mode
801 i8042.direct [HW] Put keyboard port into non-translated mode
802 i8042.dumbkbd [HW] Pretend that controller can only read data from
803 keyboard and cannot control its state
804 (Don't attempt to blink the leds)
805 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
806 i8042.nokbd [HW] Don't check/create keyboard port
807 i8042.noloop [HW] Disable the AUX Loopback command while probing
809 i8042.nomux [HW] Don't check presence of an active multiplexing
811 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
814 [HW] Frequency with which keyboard LEDs should blink
815 when kernel panics (default is 0.5 sec)
816 i8042.reset [HW] Reset the controller during init and cleanup
817 i8042.unlock [HW] Unlock (ignore) the keylock
821 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
822 indicates that the driver is running on unsupported
824 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
825 does not match list of supported models.
827 [HW] Report power status in /proc/i8k
828 (disabled by default)
829 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
832 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
833 See Documentation/mca.txt.
836 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
838 ide= [HW] (E)IDE subsystem
839 Format: ide=nodma or ide=doubler
840 See Documentation/ide/ide.txt.
842 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
843 See Documentation/ide/ide.txt.
846 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
847 Poll forces a polling idle loop that can slightly improves the performance
848 of waking up a idle CPU, but will use a lot of power and make the system
849 run hot. Not recommended.
850 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
851 to not use it because it doesn't save as much power as a normal idle
852 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
854 idle=halt. Halt is forced to be used for CPU idle.
855 In such case C2/C3 won't be used again.
856 idle=nomwait. Disable mwait for CPU C-states
858 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
859 Claim all unknown PCI IDE storage controllers.
861 ignore_loglevel [KNL]
862 Ignore loglevel setting - this will print /all/
863 kernel messages to the console. Useful for debugging.
866 Set number of hash buckets for inode cache.
869 See header of drivers/scsi/in2000.c.
873 Run specified binary instead of /sbin/init as init
876 initcall_debug [KNL] Trace initcalls as they are executed. Useful
877 for working out where the kernel is dying during
880 initrd= [BOOT] Specify the location of the initial ramdisk
882 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
900 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
902 Disable intel iommu driver.
903 igfx_off [Default Off]
904 By default, gfx is mapped as normal device. If a gfx
905 device has a dedicated DMAR unit, the DMAR unit is
906 bypassed by not enabling DMAR with this option. In
907 this case, gfx device will use physical address for
910 With this option iommu will not optimize to look
911 for io virtual address below 32 bit forcing dual
912 address cycle on pci bus for cards supporting greater
913 than 32 bit addressing. The default is to look
914 for translation below 32 bit and if not available
915 then look in the higher range.
917 With this option on every unmap_single operation will
918 result in a hardware IOTLB flush operation as opposed
919 to batching them for performance.
921 io_delay= [X86-32,X86-64] I/O delay method
923 Standard port 0x80 based delay
925 Alternate port 0xed based delay (needed on some systems)
927 Simple two microseconds delay
931 io7= [HW] IO7 for Marvel based alpha systems
932 See comment before marvel_specify_io7 in
933 arch/alpha/kernel/core_marvel.c.
936 See Documentation/filesystems/nfsroot.txt.
938 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
939 See comment before ip2_setup() in
940 drivers/char/ip2/ip2base.c.
942 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
943 See header of drivers/scsi/ips.c.
945 ports= [IP_VS_FTP] IPVS ftp helper module
947 Up to 8 (IP_VS_APP_MAX_PORTS) ports
949 Format: <port>,<port>....
952 When an interrupt is not handled search all handlers
953 for it. Intended to get systems with badly broken
957 When an interrupt is not handled search all handlers
958 for it. Also check all handlers each timer
959 interrupt. Intended to get systems with badly broken
963 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
965 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
967 <cpu number>,...,<cpu number>
969 <cpu number>-<cpu number>
970 (must be a positive range in ascending order)
972 <cpu number>,...,<cpu number>-<cpu number>
974 This option can be used to specify one or more CPUs
975 to isolate from the general SMP balancing and scheduling
976 algorithms. You can move a process onto or off an
977 "isolated" CPU via the CPU affinity syscalls or cpuset.
978 <cpu number> begins at 0 and the maximum value is
979 "number of CPUs in system - 1".
981 This option is the preferred way to isolate CPUs. The
982 alternative -- manually setting the CPU mask of all
983 tasks in the system -- can cause problems and
984 suboptimal load balancer performance.
988 js= [HW,JOY] Analog joystick
989 See Documentation/input/joystick.txt.
991 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
992 specifies the amount of memory usable by the kernel
993 for non-movable allocations. The requested amount is
994 spread evenly throughout all nodes in the system. The
995 remaining memory in each node is used for Movable
996 pages. In the event, a node is too small to have both
997 kernelcore and Movable pages, kernelcore pages will
998 take priority and other nodes will have a larger number
999 of kernelcore pages. The Movable zone is used for the
1000 allocation of pages that may be reclaimed or moved
1001 by the page migration subsystem. This means that
1002 HugeTLB pages may not be allocated from this zone.
1003 Note that allocations like PTEs-from-HighMem still
1004 use the HighMem zone if it exists, and the Normal
1005 zone if it does not.
1007 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1008 is similar to kernelcore except it specifies the
1009 amount of memory used for migratable allocations.
1010 If both kernelcore and movablecore is specified,
1011 then kernelcore will be at *least* the specified
1012 value but may be more. If movablecore on its own
1013 is specified, the administrator must be careful
1014 that the amount of memory usable for all allocations
1019 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1022 kgdboc= [HW] kgdb over consoles.
1023 Requires a tty driver that supports console polling.
1024 (only serial suported for now)
1025 Format: <serial_device>[,baud]
1027 kmac= [MIPS] korina ethernet MAC address.
1028 Configure the RouterBoard 532 series on-chip
1029 Ethernet adapter MAC address.
1035 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1038 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1041 libata.dma= [LIBATA] DMA control
1042 libata.dma=0 Disable all PATA and SATA DMA
1043 libata.dma=1 PATA and SATA Disk DMA only
1044 libata.dma=2 ATAPI (CDROM) DMA only
1045 libata.dma=4 Compact Flash DMA only
1046 Combinations also work, so libata.dma=3 enables DMA
1047 for disks and CDROMs, but not CFs.
1049 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1053 libata.force= [LIBATA] Force configurations. The format is comma
1054 separated list of "[ID:]VAL" where ID is
1055 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1056 matching port, link or device. Basically, it matches
1057 the ATA ID string printed on console by libata. If
1058 the whole ID part is omitted, the last PORT and DEVICE
1059 values are used. If ID hasn't been specified yet, the
1060 configuration applies to all ports, links and devices.
1062 If only DEVICE is omitted, the parameter applies to
1063 the port and all links and devices behind it. DEVICE
1064 number of 0 either selects the first device or the
1065 first fan-out link behind PMP device. It does not
1066 select the host link. DEVICE number of 15 selects the
1067 host link and device attached to it.
1069 The VAL specifies the configuration to force. As long
1070 as there's no ambiguity shortcut notation is allowed.
1071 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1072 The following configurations can be forced.
1074 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1075 Any ID with matching PORT is used.
1077 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1079 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1080 udma[/][16,25,33,44,66,100,133] notation is also
1083 * [no]ncq: Turn on or off NCQ.
1085 * nohrst, nosrst, norst: suppress hard, soft
1088 If there are multiple matching configurations changing
1089 the same attribute, the last one is used.
1091 load_ramdisk= [RAM] List of ramdisks to load from floppy
1092 See Documentation/ramdisk.txt.
1094 lockd.nlm_grace_period=P [NFS] Assign grace period.
1097 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1100 lockd.nlm_timeout=T [NFS] Assign timeout value.
1103 lockd.nlm_udpport=M [NFS] Assign UDP port.
1106 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1109 loglevel= All Kernel Messages with a loglevel smaller than the
1110 console loglevel will be printed to the console. It can
1111 also be changed with klogd or other programs. The
1112 loglevels are defined as follows:
1114 0 (KERN_EMERG) system is unusable
1115 1 (KERN_ALERT) action must be taken immediately
1116 2 (KERN_CRIT) critical conditions
1117 3 (KERN_ERR) error conditions
1118 4 (KERN_WARNING) warning conditions
1119 5 (KERN_NOTICE) normal but significant condition
1120 6 (KERN_INFO) informational
1121 7 (KERN_DEBUG) debug-level messages
1123 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1124 Format: { n | nk | nM }
1125 n must be a power of two. The default size
1126 is set in the kernel config file.
1128 logo.nologo [FB] Disables display of the built-in Linux logo.
1129 This may be used to provide more screen space for
1130 kernel log messages and is useful when debugging
1131 kernel boot problems.
1133 lp=0 [LP] Specify parallel ports to use, e.g,
1134 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1135 lp=reset first parallel port). 'lp=0' disables the
1136 lp=auto printer driver. 'lp=reset' (which can be
1137 specified in addition to the ports) causes
1138 attached printers to be reset. Using
1139 lp=port1,port2,... specifies the parallel ports
1140 to associate lp devices with, starting with
1141 lp0. A port specification may be 'none' to skip
1142 that lp device, or a parport name such as
1143 'parport0'. Specifying 'lp=auto' instead of a
1144 port specification list means that device IDs
1145 from each port should be examined, to see if
1146 an IEEE 1284-compliant printer is attached; if
1147 so, the driver will manage that printer.
1148 See also header of drivers/char/lp.c.
1151 Sets loops_per_jiffy to given constant, thus avoiding
1152 time-consuming boot-time autodetection (up to 250 ms per
1153 CPU). 0 enables autodetection (default). To determine
1154 the correct value for your kernel, boot with normal
1155 autodetection and see what value is printed. Note that
1156 on SMP systems the preset will be applied to all CPUs,
1157 which is likely to cause problems if your CPUs need
1158 significantly divergent settings. An incorrect value
1159 will cause delays in the kernel to be wrong, leading to
1160 unpredictable I/O errors and other breakage. Although
1161 unlikely, in the extreme case this might damage your
1165 Format: <io>,<irq>,<dma>
1167 mac5380= [HW,SCSI] Format:
1168 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1170 machvec= [IA64] Force the use of a particular machine-vector
1171 (machvec) in a generic kernel.
1172 Example: machvec=hpzx1_swiotlb
1174 max_loop= [LOOP] Maximum number of loopback devices that can
1178 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1179 should make use of. maxcpus=n : n >= 0 limits the
1180 kernel to using 'n' processors. n=0 is a special case,
1181 it is equivalent to "nosmp", which also disables
1184 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1185 equal to this physical address is ignored.
1187 max_luns= [SCSI] Maximum number of LUNs to probe.
1188 Should be between 1 and 2^32-1.
1191 [SCSI] Maximum number of LUNs received.
1192 Should be between 1 and 16384.
1196 mce [X86-32] Machine Check Exception
1198 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1200 md= [HW] RAID subsystems devices and level
1201 See Documentation/md.txt.
1204 Format: <first>,<last>
1205 Specifies range of consoles to be captured by the MDA.
1207 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1208 Amount of memory to be used when the kernel is not able
1209 to see the whole system memory or for test.
1210 [X86-32] Use together with memmap= to avoid physical
1211 address space collisions. Without memmap= PCI devices
1212 could be placed at addresses belonging to unused RAM.
1214 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1218 [KNL,SH] Allow user to override the default size for
1219 per-device physically contiguous DMA buffers.
1221 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1222 E820 memory map, as specified by the user.
1223 Such memmap=exactmap lines can be constructed based on
1224 BIOS output or other requirements. See the memmap=nn@ss
1227 memmap=nn[KMG]@ss[KMG]
1228 [KNL] Force usage of a specific region of memory
1229 Region of memory to be used, from ss to ss+nn.
1231 memmap=nn[KMG]#ss[KMG]
1232 [KNL,ACPI] Mark specific memory as ACPI data.
1233 Region of memory to be used, from ss to ss+nn.
1235 memmap=nn[KMG]$ss[KMG]
1236 [KNL,ACPI] Mark specific memory as reserved.
1237 Region of memory to be used, from ss to ss+nn.
1238 Example: Exclude memory from 0x18690000-0x1869ffff
1239 memmap=64K$0x18690000
1241 memmap=0x10000$0x18690000
1243 memory_corruption_check=0/1 [X86]
1244 Some BIOSes seem to corrupt the first 64k of
1245 memory when doing things like suspend/resume.
1246 Setting this option will scan the memory
1247 looking for corruption. Enabling this will
1248 both detect corruption and prevent the kernel
1249 from using the memory being corrupted.
1250 However, its intended as a diagnostic tool; if
1251 repeatable BIOS-originated corruption always
1252 affects the same memory, you can use memmap=
1253 to prevent the kernel from using that memory.
1255 memory_corruption_check_size=size [X86]
1256 By default it checks for corruption in the low
1257 64k, making this memory unavailable for normal
1258 use. Use this parameter to scan for
1259 corruption in more or less memory.
1261 memory_corruption_check_period=seconds [X86]
1262 By default it checks for corruption every 60
1263 seconds. Use this parameter to check at some
1264 other rate. 0 disables periodic checking.
1266 memtest= [KNL,X86] Enable memtest
1268 range: 0,4 : pattern number
1269 default : 0 <disable>
1271 meye.*= [HW] Set MotionEye Camera parameters
1272 See Documentation/video4linux/meye.txt.
1274 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1275 Multi-Function General Purpose Timers on AMD Geode
1278 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1279 the BIOS has incorrectly applied a workaround. TinyBIOS
1280 version 0.98 is known to be affected, 0.99 fixes the
1281 problem by letting the user disable the workaround.
1286 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1287 parameter allows control of the logging verbosity for
1288 the additional memory initialisation checks. A value
1289 of 0 disables mminit logging and a level of 4 will
1290 log everything. Information is printed at KERN_DEBUG
1291 so loglevel=8 may also need to be specified.
1294 [MOUSE] Maximum time between finger touching and
1295 leaving touchpad surface for touch to be considered
1296 a tap and be reported as a left button click (for
1297 touchpads working in absolute mode only).
1299 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1300 reporting absolute coordinates, such as tablets
1301 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1302 reporting absolute coordinates, such as tablets
1307 MTD_Partition= [MTD]
1308 Format: <name>,<region-number>,<size>,<offset>
1310 MTD_Region= [MTD] Format:
1311 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1314 See drivers/mtd/cmdlinepart.c.
1317 ARM/S3C2412 JIVE boot control
1319 See arch/arm/mach-s3c2412/mach-jive.c
1321 mtouchusb.raw_coordinates=
1322 [HW] Make the MicroTouch USB driver use raw coordinates
1323 ('y', default) or cooked coordinates ('n')
1325 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1328 See header of drivers/scsi/NCR_D700.c.
1332 ncr53c400= [HW,SCSI]
1334 ncr53c400a= [HW,SCSI]
1336 ncr53c406a= [HW,SCSI]
1338 ncr53c8xx= [HW,SCSI]
1340 netdev= [NET] Network devices parameters
1341 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1342 Note that mem_start is often overloaded to mean
1343 something different and driver-specific.
1344 This usage is only documented in each driver source
1348 [NETFILTER] Enable connection tracking flow accounting
1349 0 to disable accounting
1350 1 to enable accounting
1351 Default value depends on CONFIG_NF_CT_ACCT that is
1352 going to be removed in 2.6.29.
1355 See Documentation/filesystems/nfsroot.txt.
1357 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1358 See Documentation/filesystems/nfsroot.txt.
1360 nfs.callback_tcpport=
1361 [NFS] set the TCP port on which the NFSv4 callback
1362 channel should listen.
1364 nfs.idmap_cache_timeout=
1365 [NFS] set the maximum lifetime for idmapper cache
1369 [NFS] enable 64-bit inode numbers.
1370 If zero, the NFS client will fake up a 32-bit inode
1371 number for the readdir() and stat() syscalls instead
1372 of returning the full 64-bit number.
1373 The default is to return 64-bit inode numbers.
1375 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1376 when a NMI is triggered.
1377 Format: [state][,regs][,debounce][,die]
1379 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1381 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1382 emulation library even if a 387 maths coprocessor
1385 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1386 caches in the slab allocator. Saves per-node memory,
1387 but will impact performance.
1391 noapic [SMP,APIC] Tells the kernel to not make use of any
1392 IOAPICs that may be present in the system.
1394 nobats [PPC] Do not use BATs for mapping kernel lowmem
1395 on "Classic" PPC cores.
1399 nodelayacct [KNL] Disable per-task delay accounting
1401 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1403 nodsp [SH] Disable hardware DSP at boot time.
1405 noefi [X86-32,X86-64] Disable EFI runtime services support.
1409 noexec [X86-32,X86-64]
1410 On X86-32 available only on PAE configured kernels.
1411 noexec=on: enable non-executable mappings (default)
1412 noexec=off: disable non-executable mappings
1415 This affects only 32-bit executables.
1416 noexec32=on: enable non-executable mappings (default)
1417 read doesn't imply executable mappings
1418 noexec32=off: disable non-executable mappings
1419 read implies executable mappings
1421 nofpu [SH] Disable hardware FPU at boot time.
1423 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1424 register save and restore. The kernel will only save
1425 legacy floating-point registers on task switch.
1427 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1431 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1432 instruction doesn't work correctly and not to
1435 nohalt [IA-64] Tells the kernel not to use the power saving
1436 function PAL_HALT_LIGHT when idle. This increases
1437 power-consumption. On the positive side, it reduces
1438 interrupt wake-up latency, which may improve performance
1439 in certain environments such as networked servers or
1442 nohz= [KNL] Boottime enable/disable dynamic ticks
1443 Valid arguments: on, off
1446 noirqdebug [X86-32] Disables the code which attempts to detect and
1447 disable unhandled interrupt sources.
1449 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1450 broken timer IRQ sources.
1452 noisapnp [ISAPNP] Disables ISA PnP code.
1454 noinitrd [RAM] Tells the kernel not to load any configured
1459 nojitter [IA64] Disables jitter checking for ITC timers.
1461 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1463 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1465 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1467 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1468 default x2apic cluster mode on platforms
1471 noltlbs [PPC] Do not use large page/tlb entries for kernel
1472 lowmem mapping on PPC40x.
1474 nomca [IA-64] Disable machine check abort handling
1476 nomce [X86-32] Machine Check Exception
1478 nomfgpt [X86-32] Disable Multi-Function General Purpose
1479 Timer usage (for AMD Geode machines).
1481 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1483 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1484 with UP alternatives
1486 noresidual [PPC] Don't use residual data on PReP machines.
1488 noresume [SWSUSP] Disables resume and restores original swap
1491 no-scroll [VGA] Disables scrollback.
1492 This is required for the Braillex ib80-piezo Braille
1493 reader made by F.H. Papenmeier (Germany).
1497 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1499 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1500 and disable the IO APIC. legacy for "maxcpus=0".
1502 nosoftlockup [KNL] Disable the soft-lockup detector.
1504 nosync [HW,M68K] Disables sync negotiation for all devices.
1506 notsc [BUGS=X86-32] Disable Time Stamp Counter
1508 nousb [USB] Disable the USB subsystem
1512 nptcg= [IA64] Override max number of concurrent global TLB
1513 purges which is reported from either PAL_VM_SUMMARY or
1516 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1517 one of ['zone', 'node', 'default'] can be specified
1518 This can be set from sysctl after boot.
1519 See Documentation/sysctl/vm.txt for details.
1521 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1523 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1524 Rather than timing out after 20 ms if an EC
1525 command is not properly ACKed, override the length
1526 of the timeout. We have interrupts disabled while
1527 waiting for the ACK, so if this is set too high
1528 interrupts *may* be lost!
1533 oprofile.timer= [HW]
1534 Use timer interrupt instead of performance counters
1536 osst= [HW,SCSI] SCSI Tape Driver
1537 Format: <buffer_size>,<write_threshold>
1538 See also Documentation/scsi/st.txt.
1540 panic= [KNL] Kernel behaviour on panic
1543 parkbd.port= [HW] Parallel port number the keyboard adapter is
1544 connected to, default is 0.
1546 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1547 0 for XT, 1 for AT (default is AT).
1550 parport= [HW,PPT] Specify parallel ports. 0 disables.
1551 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1552 Use 'auto' to force the driver to use any
1553 IRQ/DMA settings detected (the default is to
1554 ignore detected IRQ/DMA settings because of
1555 possible conflicts). You can specify the base
1556 address, IRQ, and DMA settings; IRQ and DMA
1557 should be numbers, or 'auto' (for using detected
1558 settings on that particular port), or 'nofifo'
1559 (to avoid using a FIFO even if it is detected).
1560 Parallel ports are assigned in the order they
1561 are specified on the command line, starting
1564 parport_init_mode= [HW,PPT]
1565 Configure VIA parallel port to operate in
1566 a specific mode. This is necessary on Pegasos
1567 computer where firmware has no options for setting
1568 up parallel port mode and sets it to spp.
1569 Currently this function knows 686a and 8231 chips.
1570 Format: [spp|ps2|epp|ecp|ecpepp]
1572 pas2= [HW,OSS] Format:
1573 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1576 See header of drivers/scsi/pas16.c.
1579 Halt all CPUs after the first oops has been printed for
1580 the specified number of seconds. This is to be used if
1581 your oopses keep scrolling off the screen.
1586 See header of drivers/block/paride/pcd.c.
1587 See also Documentation/paride.txt.
1589 pci=option[,option...] [PCI] various PCI subsystem options:
1590 off [X86] don't probe for the PCI bus
1591 bios [X86-32] force use of PCI BIOS, don't access
1592 the hardware directly. Use this if your machine
1593 has a non-standard PCI host bridge.
1594 nobios [X86-32] disallow use of PCI BIOS, only direct
1595 hardware access methods are allowed. Use this
1596 if you experience crashes upon bootup and you
1597 suspect they are caused by the BIOS.
1598 conf1 [X86] Force use of PCI Configuration
1600 conf2 [X86] Force use of PCI Configuration
1602 noaer [PCIE] If the PCIEAER kernel config parameter is
1603 enabled, this kernel boot option can be used to
1604 disable the use of PCIE advanced error reporting.
1605 nodomains [PCI] Disable support for multiple PCI
1606 root domains (aka PCI segments, in ACPI-speak).
1607 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1609 nomsi [MSI] If the PCI_MSI kernel config parameter is
1610 enabled, this kernel boot option can be used to
1611 disable the use of MSI interrupts system-wide.
1612 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1613 routing table. These calls are known to be buggy
1614 on several machines and they hang the machine
1615 when used, but on other computers it's the only
1616 way to get the interrupt routing table. Try
1617 this option if the kernel is unable to allocate
1618 IRQs or discover secondary PCI buses on your
1620 rom [X86] Assign address space to expansion ROMs.
1621 Use with caution as certain devices share
1622 address decoders between ROMs and other
1624 norom [X86] Do not assign address space to
1625 expansion ROMs that do not already have
1626 BIOS assigned address ranges.
1627 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1628 assigned automatically to PCI devices. You can
1629 make the kernel exclude IRQs of your ISA cards
1631 pirqaddr=0xAAAAA [X86] Specify the physical address
1632 of the PIRQ table (normally generated
1633 by the BIOS) if it is outside the
1634 F0000h-100000h range.
1635 lastbus=N [X86] Scan all buses thru bus #N. Can be
1636 useful if the kernel is unable to find your
1637 secondary buses and you want to tell it
1638 explicitly which ones they are.
1639 assign-busses [X86] Always assign all PCI bus
1640 numbers ourselves, overriding
1641 whatever the firmware may have done.
1642 usepirqmask [X86] Honor the possible IRQ mask stored
1643 in the BIOS $PIR table. This is needed on
1644 some systems with broken BIOSes, notably
1645 some HP Pavilion N5400 and Omnibook XE3
1646 notebooks. This will have no effect if ACPI
1647 IRQ routing is enabled.
1648 noacpi [X86] Do not use ACPI for IRQ routing
1649 or for PCI scanning.
1650 use_crs [X86] Use _CRS for PCI resource
1652 routeirq Do IRQ routing for all PCI devices.
1653 This is normally done in pci_enable_device(),
1654 so this option is a temporary workaround
1655 for broken drivers that don't call it.
1656 skip_isa_align [X86] do not align io start addr, so can
1657 handle more pci cards
1658 firmware [ARM] Do not re-enumerate the bus but instead
1659 just use the configuration from the
1660 bootloader. This is currently used on
1661 IXP2000 systems where the bus has to be
1662 configured a certain way for adjunct CPUs.
1663 noearly [X86] Don't do any early type 1 scanning.
1664 This might help on some broken boards which
1665 machine check when some devices' config space
1666 is read. But various workarounds are disabled
1667 and some IOMMU drivers will not work.
1668 bfsort Sort PCI devices into breadth-first order.
1669 This sorting is done to get a device
1670 order compatible with older (<= 2.4) kernels.
1671 nobfsort Don't sort PCI devices into breadth-first order.
1672 cbiosize=nn[KMG] The fixed amount of bus space which is
1673 reserved for the CardBus bridge's IO window.
1674 The default value is 256 bytes.
1675 cbmemsize=nn[KMG] The fixed amount of bus space which is
1676 reserved for the CardBus bridge's memory
1677 window. The default value is 64 megabytes.
1679 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1682 force Enable ASPM even on devices that claim not to support it.
1683 WARNING: Forcing ASPM on may cause system lockups.
1685 pcmv= [HW,PCMCIA] BadgePAD 4
1688 See Documentation/paride.txt.
1690 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1693 See arch/parisc/kernel/pdc_chassis.c
1696 See Documentation/paride.txt.
1699 See Documentation/paride.txt.
1701 pirq= [SMP,APIC] Manual mp-table setup
1702 See Documentation/x86/i386/IO-APIC.txt.
1704 plip= [PPT,NET] Parallel port network link
1705 Format: { parport<nr> | timid | 0 }
1706 See also Documentation/parport.txt.
1708 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1709 Override pmtimer IOPort with a hex value.
1713 Enable PNP debug messages. This depends on the
1714 CONFIG_PNP_DEBUG_MESSAGES option.
1720 { on | off | curr | res | no-curr | no-res }
1723 [ISAPNP] Exclude IRQs for the autoconfiguration
1726 [ISAPNP] Exclude DMAs for the autoconfiguration
1728 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1729 Ranges are in pairs (I/O port base and size).
1732 [ISAPNP] Exclude memory regions for the
1734 Ranges are in pairs (memory base and size).
1737 Enables pr_debug()/dev_dbg() calls if
1738 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1739 be switched on/off via <debugfs>/dynamic_printk/modules
1741 print-fatal-signals=
1742 [KNL] debug: print fatal signals
1743 print-fatal-signals=1: print segfault info to
1747 printk.time= Show timing data prefixed to each printk message line
1748 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1750 profile= [KNL] Enable kernel profiling via /proc/profile
1751 Format: [schedule,]<number>
1752 Param: "schedule" - profile schedule points.
1753 Param: <number> - step/bucket size as a power of 2 for
1754 statistical time based profiling.
1755 Param: "sleep" - profile D-state sleeping (millisecs).
1756 Requires CONFIG_SCHEDSTATS
1757 Param: "kvm" - profile VM exits.
1759 processor.max_cstate= [HW,ACPI]
1760 Limit processor to maximum C-state
1761 max_cstate=9 overrides any DMI blacklist limit.
1763 processor.nocst [HW,ACPI]
1764 Ignore the _CST method to determine C-states,
1765 instead using the legacy FADT method
1767 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1769 See Documentation/ramdisk.txt.
1771 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1772 probe for; one of (bare|imps|exps|lifebook|any).
1773 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1775 psmouse.resetafter= [HW,MOUSE]
1776 Try to reset the device after so many bad packets
1779 [HW,MOUSE] Set desired mouse resolution, in dpi.
1780 psmouse.smartscroll=
1781 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1782 0 = disabled, 1 = enabled (default).
1784 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1786 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1789 See Documentation/paride.txt.
1792 [KNL] Number of legacy pty's. Overwrites compiled-in
1795 quiet [KNL] Disable most log messages
1800 See Documentation/md.txt.
1802 ramdisk_blocksize= [RAM]
1803 See Documentation/ramdisk.txt.
1805 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1806 See Documentation/ramdisk.txt.
1808 rcupdate.blimit= [KNL,BOOT]
1809 Set maximum number of finished RCU callbacks to process
1812 rcupdate.qhimark= [KNL,BOOT]
1813 Set threshold of queued
1814 RCU callbacks over which batch limiting is disabled.
1816 rcupdate.qlowmark= [KNL,BOOT]
1817 Set threshold of queued RCU callbacks below which
1818 batch limiting is re-enabled.
1822 Run specified binary instead of /init from the ramdisk,
1823 used for early userspace startup. See initrd.
1825 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1826 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1827 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1830 [KNL, SMP] Set scheduler's default relax_domain_level.
1831 See Documentation/cpusets.txt.
1833 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1835 reservetop= [X86-32]
1837 Reserves a hole at the top of the kernel virtual
1840 reset_devices [KNL] Force drivers to reset the underlying device
1841 during initialization.
1844 Specify the partition device for software suspend
1846 resume_offset= [SWSUSP]
1847 Specify the offset from the beginning of the partition
1848 given by "resume=" at which the swap header is located,
1849 in <PAGE_SIZE> units (needed only for swap files).
1850 See Documentation/power/swsusp-and-swap-files.txt
1852 retain_initrd [RAM] Keep initrd memory after extraction
1854 rhash_entries= [KNL,NET]
1855 Set number of hash buckets for route cache
1857 riscom8= [HW,SERIAL]
1858 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1860 ro [KNL] Mount root device read-only on boot
1862 root= [KNL] Root filesystem
1864 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1865 mount the root filesystem
1867 rootflags= [KNL] Set root filesystem mount option string
1869 rootfstype= [KNL] Set root filesystem type
1871 rootwait [KNL] Wait (indefinitely) for root device to show up.
1872 Useful for devices that are detected asynchronously
1873 (e.g. USB and MMC devices).
1875 root_plug.vendor_id=
1876 [ROOTPLUG] Override the default vendor ID
1878 root_plug.product_id=
1879 [ROOTPLUG] Override the default product ID
1882 [ROOTPLUG] Enable debugging output
1884 rw [KNL] Mount root device read-write on boot
1886 S [KNL] Run init in single mode
1889 See drivers/net/irda/sa1100_ir.c.
1891 sbni= [NET] Granch SBNI12 leased line adapter
1893 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1894 Format: <io>[,<timeout>[,<isapnp>]]
1896 scsi_debug_*= [SCSI]
1897 See drivers/scsi/scsi_debug.c.
1899 scsi_default_dev_flags=
1900 [SCSI] SCSI default device flags
1903 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1904 Format: <vendor>:<model>:<flags>
1905 (flags are integer value)
1907 scsi_logging_level= [SCSI] a bit mask of logging levels
1908 See drivers/scsi/scsi_logging.h for bits. Also
1909 settable via sysctl at dev.scsi.logging_level
1910 (/proc/sys/dev/scsi/logging_level).
1911 There is also a nice 'scsi_logging_level' script in the
1912 S390-tools package, available for download at
1913 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1915 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1916 discovered. async scans them in kernel threads,
1917 allowing boot to proceed. none ignores them, expecting
1918 user space to do the scan.
1920 selinux [SELINUX] Disable or enable SELinux at boot time.
1921 Format: { "0" | "1" }
1922 See security/selinux/Kconfig help text.
1925 Default value is set via kernel config option.
1926 If enabled at boot time, /selinux/disable can be used
1927 later to disable prior to initial policy load.
1929 selinux_compat_net =
1930 [SELINUX] Set initial selinux_compat_net flag value.
1931 Format: { "0" | "1" }
1932 0 -- use new secmark-based packet controls
1933 1 -- use legacy packet controls
1934 Default value is 0 (preferred).
1935 Value can be changed at runtime via
1936 /selinux/compat_net.
1938 serialnumber [BUGS=X86-32]
1941 Maximal number of shapers.
1943 show_msr= [x86] show boot-time MSR settings
1944 Format: { <integer> }
1945 Show boot-time (BIOS-initialized) MSR settings.
1946 The parameter means the number of CPUs to show,
1947 for example 1 means boot CPU only.
1950 See header of drivers/scsi/sim710.c.
1957 slub_debug[=options[,slabs]] [MM, SLUB]
1958 Enabling slub_debug allows one to determine the
1959 culprit if slab objects become corrupted. Enabling
1960 slub_debug can create guard zones around objects and
1961 may poison objects when not in use. Also tracks the
1962 last alloc / free. For more information see
1963 Documentation/vm/slub.txt.
1965 slub_max_order= [MM, SLUB]
1966 Determines the maximum allowed order for slabs.
1967 A high setting may cause OOMs due to memory
1968 fragmentation. For more information see
1969 Documentation/vm/slub.txt.
1971 slub_min_objects= [MM, SLUB]
1972 The minimum number of objects per slab. SLUB will
1973 increase the slab order up to slub_max_order to
1974 generate a sufficiently large slab able to contain
1975 the number of objects indicated. The higher the number
1976 of objects the smaller the overhead of tracking slabs
1977 and the less frequently locks need to be acquired.
1978 For more information see Documentation/vm/slub.txt.
1980 slub_min_order= [MM, SLUB]
1981 Determines the mininum page order for slabs. Must be
1982 lower than slub_max_order.
1983 For more information see Documentation/vm/slub.txt.
1985 slub_nomerge [MM, SLUB]
1986 Disable merging of slabs with similar size. May be
1987 necessary if there is some reason to distinguish
1988 allocs to different slabs. Debug options disable
1989 merging on their own.
1990 For more information see Documentation/vm/slub.txt.
1993 Format: <io1>[,<io2>[,...,<io8>]]
1995 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1996 attempt to substitute SMP alternatives once at boot.
1998 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1999 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2000 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2001 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2002 smsc-ircc2.ircc_irq= [HW] IRQ line
2003 smsc-ircc2.ircc_dma= [HW] DMA channel
2004 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2005 0: Toshiba Satellite 1800 (GP data pin select)
2006 1: Fast pin select (default)
2009 snd-ad1816a= [HW,ALSA]
2011 snd-ad1848= [HW,ALSA]
2013 snd-ali5451= [HW,ALSA]
2015 snd-als100= [HW,ALSA]
2017 snd-als4000= [HW,ALSA]
2019 snd-azt2320= [HW,ALSA]
2021 snd-cmi8330= [HW,ALSA]
2023 snd-cmipci= [HW,ALSA]
2025 snd-cs4231= [HW,ALSA]
2027 snd-cs4232= [HW,ALSA]
2029 snd-cs4236= [HW,ALSA]
2031 snd-cs4281= [HW,ALSA]
2033 snd-cs46xx= [HW,ALSA]
2035 snd-dt019x= [HW,ALSA]
2037 snd-dummy= [HW,ALSA]
2039 snd-emu10k1= [HW,ALSA]
2041 snd-ens1370= [HW,ALSA]
2043 snd-ens1371= [HW,ALSA]
2045 snd-es968= [HW,ALSA]
2047 snd-es1688= [HW,ALSA]
2049 snd-es18xx= [HW,ALSA]
2051 snd-es1938= [HW,ALSA]
2053 snd-es1968= [HW,ALSA]
2055 snd-fm801= [HW,ALSA]
2057 snd-gusclassic= [HW,ALSA]
2059 snd-gusextreme= [HW,ALSA]
2061 snd-gusmax= [HW,ALSA]
2065 snd-ice1712= [HW,ALSA]
2067 snd-intel8x0= [HW,ALSA]
2069 snd-interwave= [HW,ALSA]
2074 snd-korg1212= [HW,ALSA]
2076 snd-maestro3= [HW,ALSA]
2078 snd-mpu401= [HW,ALSA]
2080 snd-mtpav= [HW,ALSA]
2082 snd-nm256= [HW,ALSA]
2084 snd-opl3sa2= [HW,ALSA]
2092 snd-opti93x= [HW,ALSA]
2096 snd-rme32= [HW,ALSA]
2098 snd-rme96= [HW,ALSA]
2100 snd-rme9652= [HW,ALSA]
2106 snd-sbawe= [HW,ALSA]
2108 snd-serial= [HW,ALSA]
2110 snd-sgalaxy= [HW,ALSA]
2112 snd-sonicvibes= [HW,ALSA]
2117 snd-sun-cs4231= [HW,ALSA]
2119 snd-trident= [HW,ALSA]
2121 snd-usb-audio= [HW,ALSA,USB]
2123 snd-via82xx= [HW,ALSA]
2125 snd-virmidi= [HW,ALSA]
2127 snd-wavefront= [HW,ALSA]
2129 snd-ymfpci= [HW,ALSA]
2132 [KNL] Should the soft-lockup detector generate panics.
2134 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2135 See Documentation/sonypi.txt
2137 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2138 See Documentation/specialix.txt.
2140 spia_io_base= [HW,MTD]
2146 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2148 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2149 See Documentation/scsi/st.txt.
2153 Set the STI (builtin display/keyboard on the HP-PARISC
2154 machines) console (graphic card) which should be used
2155 as the initial boot-console.
2156 See also comment in drivers/video/console/sticore.c.
2159 See comment in drivers/video/console/sticore.c.
2162 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2166 Control how the NFS server code allocates CPUs to
2167 service thread pools. Depending on how many NICs
2168 you have and where their interrupts are bound, this
2169 option will affect which CPUs will do NFS serving.
2170 Note: this parameter cannot be changed while the
2171 NFS server is running.
2173 auto the server chooses an appropriate mode
2174 automatically using heuristics
2175 global a single global pool contains all CPUs
2176 percpu one pool for each CPU
2177 pernode one pool for each NUMA node (equivalent
2178 to global on non-NUMA machines)
2180 swiotlb= [IA-64] Number of I/O TLB slabs
2184 sym53c416= [HW,SCSI]
2185 See header of drivers/scsi/sym53c416.c.
2187 sysrq_always_enabled
2189 Ignore sysrq setting - this boot parameter will
2190 neutralize any effect of /proc/sys/kernel/sysrq.
2191 Useful for debugging.
2194 See header of drivers/scsi/t128.c.
2198 test_suspend= [SUSPEND]
2199 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2200 standby suspend) as the system sleep state to briefly
2201 enter during system startup. The system is woken from
2202 this state using a wakeup-capable RTC alarm.
2204 thash_entries= [KNL,NET]
2205 Set number of hash buckets for TCP connection
2207 thermal.act= [HW,ACPI]
2208 -1: disable all active trip points in all thermal zones
2209 <degrees C>: override all lowest active trip points
2211 thermal.crt= [HW,ACPI]
2212 -1: disable all critical trip points in all thermal zones
2213 <degrees C>: override all critical trip points
2215 thermal.nocrt= [HW,ACPI]
2216 Set to disable actions on ACPI thermal zone
2217 critical and hot trip points.
2219 thermal.off= [HW,ACPI]
2220 1: disable ACPI thermal control
2222 thermal.psv= [HW,ACPI]
2223 -1: disable all passive trip points
2224 <degrees C>: override all passive trip points to this value
2226 thermal.tzp= [HW,ACPI]
2227 Specify global default ACPI thermal zone polling rate
2228 <deci-seconds>: poll all this frequency
2229 0: no polling (default)
2232 See comment before function dc390_setup() in
2233 drivers/scsi/tmscsim.c.
2237 trix= [HW,OSS] MediaTrix AudioTrix Pro
2239 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2241 turbografx.map[2|3]= [HW,JOY]
2242 TurboGraFX parallel port interface
2244 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2245 See also Documentation/input/joystick-parport.txt
2247 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2248 See header of drivers/scsi/u14-34f.c.
2257 [USB] Ignore overcurrent events (default N).
2258 Some badly-designed motherboards generate lots of
2259 bogus events, for ports that aren't wired to
2260 anything. Set this parameter to avoid log spamming.
2261 Note that genuine overcurrent events won't be
2266 Set unknown_nmi_panic=1 early on boot.
2268 usbcore.autosuspend=
2269 [USB] The autosuspend time delay (in seconds) used
2270 for newly-detected USB devices (default 2). This
2271 is the time required before an idle device will be
2272 autosuspended. Devices for which the delay is set
2273 to a negative value won't be autosuspended at all.
2275 usbcore.usbfs_snoop=
2276 [USB] Set to log all usbfs traffic (default 0 = off).
2278 usbcore.blinkenlights=
2279 [USB] Set to cycle leds on hubs (default 0 = off).
2281 usbcore.old_scheme_first=
2282 [USB] Start with the old device initialization
2283 scheme (default 0 = off).
2285 usbcore.use_both_schemes=
2286 [USB] Try the other device initialization scheme
2287 if the first one fails (default 1 = enabled).
2289 usbcore.initial_descriptor_timeout=
2290 [USB] Specifies timeout for the initial 64-byte
2291 USB_REQ_GET_DESCRIPTOR request in milliseconds
2292 (default 5000 = 5.0 seconds).
2295 [USBHID] The interval which mice are to be polled at.
2297 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2298 kernel's map of available physical RAM.
2300 vdso= [X86-32,SH,x86-64]
2301 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2302 vdso=1: enable VDSO (default)
2303 vdso=0: disable VDSO mapping
2305 vdso32= [X86-32,X86-64]
2306 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2307 vdso32=1: enable 32-bit VDSO (default)
2308 vdso32=0: disable 32-bit VDSO mapping
2311 vector=percpu: enable percpu vector domain
2313 video= [FB] Frame buffer configuration
2314 See Documentation/fb/modedb.txt.
2316 vga= [BOOT,X86-32] Select a particular video mode
2317 See Documentation/x86/i386/boot.txt and
2318 Documentation/svga.txt.
2319 Use vga=ask for menu.
2320 This is actually a boot loader parameter; the value is
2321 passed to the kernel using a special protocol.
2323 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2324 size of <nn>. This can be used to increase the
2325 minimum size (128MB on x86). It can also be used to
2326 decrease the size and leave more room for directly
2329 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2332 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2335 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2338 waveartist= [HW,OSS]
2339 Format: <io>,<irq>,<dma>,<dma2>
2342 See header of drivers/scsi/wd33c93.c.
2345 See header of drivers/scsi/wd7000.c.
2348 See Documentation/watchdog/wdt.txt.
2350 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2351 xd_geo= See header of drivers/block/xd.c.
2353 xirc2ps_cs= [NET,PCMCIA]
2355 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2357 norandmaps Don't use address space randomization
2358 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2360 ______________________________________________________________________
2364 Add documentation for ALSA options.
2365 Add more DRM drivers.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob