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 Hyphens (dashes) and underscores are equivalent in parameter names, so
21 log_buf_len=1M print-fatal-signals=1
22 can also be entered as
23 log-buf-len=1M print_fatal_signals=1
26 This document may not be entirely up to date and comprehensive. The command
27 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
28 module. Loadable modules, after being loaded into the running kernel, also
29 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
30 parameters may be changed at runtime by the command
31 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
33 The parameters listed below are only valid if certain kernel build options were
34 enabled and if respective hardware is present. The text in square brackets at
35 the beginning of each description states the restrictions within which a
36 parameter is applicable:
38 ACPI ACPI support is enabled.
39 AGP AGP (Accelerated Graphics Port) is enabled.
40 ALSA ALSA sound support is enabled.
41 APIC APIC support is enabled.
42 APM Advanced Power Management support is enabled.
43 AVR32 AVR32 architecture is enabled.
44 AX25 Appropriate AX.25 support is enabled.
45 BLACKFIN Blackfin architecture is enabled.
46 DRM Direct Rendering Management support is enabled.
47 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
48 EFI EFI Partitioning (GPT) is enabled
49 EIDE EIDE/ATAPI support is enabled.
50 FB The frame buffer device is enabled.
51 HW Appropriate hardware is enabled.
52 IA-64 IA-64 architecture is enabled.
53 IMA Integrity measurement architecture is enabled.
54 IOSCHED More than one I/O scheduler is enabled.
55 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
56 ISAPNP ISA PnP code is enabled.
57 ISDN Appropriate ISDN support is enabled.
58 JOY Appropriate joystick support is enabled.
59 LIBATA Libata driver is enabled
60 LP Printer support is enabled.
61 LOOP Loopback device support is enabled.
62 M68k M68k architecture is enabled.
63 These options have more detailed description inside of
64 Documentation/m68k/kernel-options.txt.
65 MCA MCA bus support is enabled.
66 MDA MDA console support is enabled.
67 MOUSE Appropriate mouse support is enabled.
68 MSI Message Signaled Interrupts (PCI).
69 MTD MTD (Memory Technology Device) support is enabled.
70 NET Appropriate network support is enabled.
71 NUMA NUMA support is enabled.
72 GENERIC_TIME The generic timeofday code is enabled.
73 NFS Appropriate NFS support is enabled.
74 OSS OSS sound support is enabled.
75 PV_OPS A paravirtualized kernel is enabled.
76 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
77 PARISC The PA-RISC architecture is enabled.
78 PCI PCI bus support is enabled.
79 PCIE PCI Express support is enabled.
80 PCMCIA The PCMCIA subsystem is enabled.
81 PNP Plug & Play support is enabled.
82 PPC PowerPC architecture is enabled.
83 PPT Parallel port support is enabled.
84 PS2 Appropriate PS/2 support is enabled.
85 RAM RAM disk support is enabled.
86 ROOTPLUG The example Root Plug LSM is enabled.
87 S390 S390 architecture is enabled.
88 SCSI Appropriate SCSI support is enabled.
89 A lot of drivers has their options described inside of
91 SECURITY Different security models are enabled.
92 SELINUX SELinux support is enabled.
93 SERIAL Serial support is enabled.
94 SH SuperH architecture is enabled.
95 SMP The kernel is an SMP kernel.
96 SPARC Sparc architecture is enabled.
97 SWSUSP Software suspend (hibernation) is enabled.
98 SUSPEND System suspend states are enabled.
99 FTRACE Function tracing enabled.
100 TS Appropriate touchscreen support is enabled.
101 UMS USB Mass Storage support is enabled.
102 USB USB support is enabled.
103 USBHID USB Human Interface Device support is enabled.
104 V4L Video For Linux support is enabled.
105 VGA The VGA console has been enabled.
106 VT Virtual terminal support is enabled.
107 WDT Watchdog support is enabled.
108 XT IBM PC/XT MFM hard disk support is enabled.
109 X86-32 X86-32, aka i386 architecture is enabled.
110 X86-64 X86-64 architecture is enabled.
111 More X86-64 boot options can be found in
112 Documentation/x86/x86_64/boot-options.txt .
113 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
115 In addition, the following text indicates that the option:
117 BUGS= Relates to possible processor bugs on the said processor.
118 KNL Is a kernel start-up parameter.
119 BOOT Is a boot loader parameter.
121 Parameters denoted with BOOT are actually interpreted by the boot
122 loader, and have no meaning to the kernel directly.
123 Do not modify the syntax of boot loader parameters without extreme
124 need or coordination with <Documentation/x86/boot.txt>.
126 There are also arch-specific kernel-parameters not documented here.
127 See for example <Documentation/x86/x86_64/boot-options.txt>.
129 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
130 a trailing = on the name of any parameter states that that parameter will
131 be entered as an environment variable, whereas its absence indicates that
132 it will appear as a kernel argument readable via /proc/cmdline by programs
133 running once the system is up.
135 The number of kernel parameters is not limited, but the length of the
136 complete command line (parameters including spaces etc.) is limited to
137 a fixed number of characters. This limit depends on the architecture
138 and is between 256 and 4096 characters. It is defined in the file
139 ./include/asm/setup.h as COMMAND_LINE_SIZE.
143 Advanced Configuration and Power Interface
144 Format: { force | off | ht | strict | noirq | rsdt }
145 force -- enable ACPI if default was off
146 off -- disable ACPI if default was on
147 noirq -- do not use ACPI for IRQ routing
148 ht -- run only enough ACPI to enable Hyper Threading
149 strict -- Be less tolerant of platforms that are not
150 strictly ACPI specification compliant.
151 rsdt -- prefer RSDT over (default) XSDT
153 See also Documentation/power/pm.txt, pci=noacpi
155 acpi_apic_instance= [ACPI, IOAPIC]
157 2: use 2nd APIC table, if available
158 1,0: use 1st APIC table
161 acpi_backlight= [HW,ACPI]
162 acpi_backlight=vendor
164 If set to vendor, prefer vendor specific driver
165 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
166 of the ACPI video.ko driver.
168 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
169 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
171 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
172 debug output. Bits in debug_layer correspond to a
173 _COMPONENT in an ACPI source file, e.g.,
174 #define _COMPONENT ACPI_PCI_COMPONENT
175 Bits in debug_level correspond to a level in
176 ACPI_DEBUG_PRINT statements, e.g.,
177 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
178 The debug_level mask defaults to "info". See
179 Documentation/acpi/debug.txt for more information about
180 debug layers and levels.
182 Enable processor driver info messages:
183 acpi.debug_layer=0x20000000
184 Enable PCI/PCI interrupt routing info messages:
185 acpi.debug_layer=0x400000
186 Enable AML "Debug" output, i.e., stores to the Debug
187 object while interpreting AML:
188 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
189 Enable all messages related to ACPI hardware:
190 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
192 Some values produce so much output that the system is
193 unusable. The "log_buf_len" parameter may be useful
194 if you need to capture more output.
196 acpi_display_output= [HW,ACPI]
197 acpi_display_output=vendor
198 acpi_display_output=video
201 acpi_irq_balance [HW,ACPI]
202 ACPI will balance active IRQs
205 acpi_irq_nobalance [HW,ACPI]
206 ACPI will not move active IRQs (default)
209 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
210 Format: <irq>,<irq>...
212 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
214 Format: <irq>,<irq>...
216 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
218 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
219 Format: To spoof as Windows 98: ="Microsoft Windows"
221 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
222 acpi_osi="string1" # add string1 -- only one string
223 acpi_osi="!string2" # remove built-in string2
224 acpi_osi= # disable all strings
227 Override the pmtimer bug detection: force the kernel
228 to assume that this machine's pmtimer latches its value
229 and always returns good values.
231 acpi.power_nocheck= [HW,ACPI]
232 Format: 1/0 enable/disable the check of power state.
233 On some bogus BIOS the _PSC object/_STA object of
234 power resource can't return the correct device power
235 state. In such case it is unneccessary to check its
236 power state again in power transition.
237 1 : disable the power state check
239 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
240 Format: { level | edge | high | low }
242 acpi_serialize [HW,ACPI] force serialization of AML methods
244 acpi_skip_timer_override [HW,ACPI]
245 Recognize and ignore IRQ0/pin2 Interrupt Override.
246 For broken nForce2 BIOS resulting in XT-PIC timer.
248 acpi_sleep= [HW,ACPI] Sleep options
249 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
250 old_ordering, s4_nonvs }
251 See Documentation/power/video.txt for information on
253 s3_beep is for debugging; it makes the PC's speaker beep
254 as soon as the kernel's real-mode entry point is called.
255 s4_nohwsig prevents ACPI hardware signature from being
256 used during resume from hibernation.
257 old_ordering causes the ACPI 1.0 ordering of the _PTS
258 control method, with respect to putting devices into
259 low power states, to be enforced (the ACPI 2.0 ordering
260 of _PTS is used by default).
261 s4_nonvs prevents the kernel from saving/restoring the
262 ACPI NVS memory during hibernation.
264 acpi_use_timer_override [HW,ACPI]
265 Use timer override. For some broken Nvidia NF5 boards
266 that require a timer override, but don't have HPET
268 acpi_enforce_resources= [ACPI]
269 { strict | lax | no }
270 Check for resource conflicts between native drivers
271 and ACPI OperationRegions (SystemIO and SystemMemory
272 only). IO ports and memory declared in ACPI might be
273 used by the ACPI subsystem in arbitrary AML code and
274 can interfere with legacy drivers.
275 strict (default): access to resources claimed by ACPI
276 is denied; legacy drivers trying to access reserved
277 resources will fail to bind to device using them.
278 lax: access to resources claimed by ACPI is allowed;
279 legacy drivers trying to access reserved resources
280 will bind successfully but a warning message is logged.
281 no: ACPI OperationRegions are not marked as reserved,
282 no further checks are performed.
285 Format: <io>,<irq>,<dma>,<dma2>,<type>
287 add_efi_memmap [EFI; X86] Include EFI memory map in
288 kernel's map of available physical RAM.
291 See header of drivers/scsi/advansys.c.
293 advwdt= [HW,WDT] Advantech WDT
294 Format: <iostart>,<iostop>
296 aedsp16= [HW,OSS] Audio Excel DSP 16
297 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
298 See also header of sound/oss/aedsp16.c.
301 { off | try_unsupported }
302 off: disable AGP support
303 try_unsupported: try to drive unsupported chipsets
304 (may crash computer or cause data corruption)
307 See Documentation/scsi/aha152x.txt.
310 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
313 See Documentation/scsi/aic7xxx.txt.
316 See Documentation/scsi/aic79xx.txt.
318 amd_iommu= [HW,X86-84]
319 Pass parameters to the AMD IOMMU driver in the system.
321 isolate - enable device isolation (each device, as far
322 as possible, will get its own protection
324 share - put every device behind one IOMMU into the
325 same protection domain
326 fullflush - enable flushing of IO/TLB entries when
327 they are unmapped. Otherwise they are
328 flushed before they will be reused, which
331 amd_iommu_size= [HW,X86-64]
332 Define the size of the aperture for the AMD IOMMU
333 driver. Possible values are:
334 '32M', '64M' (default), '128M', '256M', '512M', '1G'
336 amijoy.map= [HW,JOY] Amiga joystick support
337 Map of devices attached to JOY0DAT and JOY1DAT
339 See also Documentation/kernel/input/joystick.txt
341 analog.map= [HW,JOY] Analog joystick and gamepad support
342 Specifies type or capabilities of an analog joystick
343 connected to one of 16 gameports
344 Format: <type1>,<type2>,..<type16>
347 Power management functions (SPARCstation-4/5 + deriv.)
349 Disable APC CPU standby support. SPARCstation-Fox does
350 not play well with APC CPU idle - disable it if you have
351 APC and your system crashes randomly.
353 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
354 Change the output verbosity whilst booting
355 Format: { quiet (default) | verbose | debug }
356 Change the amount of debugging information output
357 when initialising the APIC and IO-APIC components.
359 apm= [APM] Advanced Power Management
360 See header of arch/x86/kernel/apm_32.c.
362 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
363 Format: <io>,<irq>,<nodeID>
367 atarimouse= [HW,MOUSE] Atari Mouse
369 atascsi= [HW,SCSI] Atari SCSI
371 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
372 EzKey and similar keyboards
374 atkbd.reset= [HW] Reset keyboard during initialization
376 atkbd.set= [HW] Select keyboard code set
377 Format: <int> (2 = AT (default), 3 = PS/2)
379 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
382 atkbd.softraw= [HW] Choose between synthetic and real raw mode
383 Format: <bool> (0 = real, 1 = synthetic (default))
385 atkbd.softrepeat= [HW]
386 Use software keyboard repeat
390 baycom_epp= [HW,AX25]
393 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
395 See header of drivers/net/hamradio/baycom_par.c.
397 baycom_ser_fdx= [HW,AX25]
398 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
399 Format: <io>,<irq>,<mode>[,<baud>]
400 See header of drivers/net/hamradio/baycom_ser_fdx.c.
402 baycom_ser_hdx= [HW,AX25]
403 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
404 Format: <io>,<irq>,<mode>
405 See header of drivers/net/hamradio/baycom_ser_hdx.c.
407 boot_delay= Milliseconds to delay each printk during boot.
408 Values larger than 10 seconds (10000) are changed to
412 bootmem_debug [KNL] Enable bootmem allocator debug messages.
414 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
415 bttv.radio= Most important insmod options are available as
417 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
418 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
421 See drivers/scsi/BusLogic.c, comment before function
422 BusLogic_ParseDriverOptions().
424 c101= [NET] Moxa C101 synchronous serial card
426 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
427 Sometimes CPU hardware bugs make them report the cache
428 size incorrectly. The kernel will attempt work arounds
429 to fix known problems, but for some CPUs it is not
430 possible to determine what the correct size should be.
431 This option provides an override for these situations.
434 [SECURITY] Disable capabilities. This would normally
435 be used only if an alternative security model is to be
436 configured. Potentially dangerous and should only be
437 used if you are entirely sure of the consequences.
439 ccw_timeout_log [S390]
440 See Documentation/s390/CommonIO for details.
442 cgroup_disable= [KNL] Disable a particular controller
443 Format: {name of the controller(s) to disable}
444 {Currently supported controllers - "memory"}
446 checkreqprot [SELINUX] Set initial checkreqprot flag value.
447 Format: { "0" | "1" }
448 See security/selinux/Kconfig help text.
449 0 -- check protection applied by kernel (includes
450 any implied execute protection).
451 1 -- check protection requested by application.
452 Default value is set via a kernel config option.
453 Value can be changed at runtime via
454 /selinux/checkreqprot.
457 See Documentation/s390/CommonIO for details.
459 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
461 Forces specified clocksource (if available) to be used
462 when calculating gettimeofday(). If specified
463 clocksource is not available, it defaults to PIT.
464 Format: { pit | tsc | cyclone | pmtmr }
466 clocksource= [GENERIC_TIME] Override the default clocksource
468 Override the default clocksource and use the clocksource
469 with the name specified.
470 Some clocksource names to choose from, depending on
472 [all] jiffies (this is the base, fallback clocksource)
474 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
475 pxa_timer,timer3,32k_counter,timer0_1
477 [X86-32] pit,hpet,tsc,vmi-timer;
478 scx200_hrt on Geode; cyclone on IBM x440
486 clearcpuid=BITNUM [X86]
487 Disable CPUID feature X for the kernel. See
488 arch/x86/include/asm/cpufeature.h for the valid bit
489 numbers. Note the Linux specific bits are not necessarily
490 stable over kernel options, but the vendor specific
492 Also note that user programs calling CPUID directly
493 or using the feature without checking anything
494 will still see it. This just prevents it from
495 being used by the kernel or shown in /proc/cpuinfo.
496 Also note the kernel might malfunction if you disable
499 code_bytes [X86] How many bytes of object code to print
504 com20020= [HW,NET] ARCnet - COM20020 chipset
506 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
508 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
512 ARCnet - COM90xx chipset (memory-mapped buffers)
513 Format: <io>[,<irq>[,<memstart>]]
515 condev= [HW,S390] console device
518 console= [KNL] Output console device and options.
520 tty<n> Use the virtual console device <n>.
524 Use the specified serial port. The options are of
525 the form "bbbbpnf", where "bbbb" is the baud rate,
526 "p" is parity ("n", "o", or "e"), "n" is number of
527 bits, and "f" is flow control ("r" for RTS or
528 omit it). Default is "9600n8".
530 See Documentation/serial-console.txt for more
532 Documentation/networking/netconsole.txt for an
535 uart[8250],io,<addr>[,options]
536 uart[8250],mmio,<addr>[,options]
537 Start an early, polled-mode console on the 8250/16550
538 UART at the specified I/O port or MMIO address,
539 switching to the matching ttyS device later. The
540 options are the same as for ttyS, above.
542 If the device connected to the port is not a TTY but a braille
543 device, prepend "brl," before the device type, for instance
545 For now, only VisioBraille is supported.
548 [KNL] Change the default value for
549 /proc/<pid>/coredump_filter.
550 See also Documentation/filesystems/proc.txt.
552 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
554 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
556 crashkernel=nn[KMG]@ss[KMG]
557 [KNL] Reserve a chunk of physical memory to
558 hold a kernel to switch to with kexec on panic.
560 crashkernel=range1:size1[,range2:size2,...][@offset]
561 [KNL] Same as above, but depends on the memory
562 in the running system. The syntax of range is
563 start-[end] where start and end are both
564 a memory unit (amount[KMG]). See also
565 Documentation/kdump/kdump.txt for a example.
570 cs89x0_media= [HW,NET]
571 Format: { rj45 | aui | bnc }
574 See header of drivers/s390/block/dasd_devmap.c.
576 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
577 (one device per port)
578 Format: <port#>,<type>
579 See also Documentation/input/joystick-parport.txt
581 debug [KNL] Enable kernel debugging (events log level).
584 [KNL] verbose self-tests
586 Print debugging info while doing the locking API
588 We default to 0 (no extra messages), setting it to
589 1 will print _a lot_ more information - normally
590 only useful to kernel developers.
592 debug_objects [KNL] Enable object debugging
595 [KNL] Disable object debugging
597 debugpat [X86] Enable PAT debugging
599 decnet.addr= [HW,NET]
600 Format: <area>[,<node>]
601 See also Documentation/networking/decnet.txt.
604 [same as hugepagesz=] The size of the default
605 HugeTLB page size. This is the size represented by
606 the legacy /proc/ hugepages APIs, used for SHM, and
607 default size when mounting hugetlbfs filesystems.
608 Defaults to the default architecture's huge page size
612 Set number of hash buckets for dentry cache.
615 IO parameters + enable/disable command.
617 digiepca= [HW,SERIAL]
618 See drivers/char/README.epca and
619 Documentation/serial/digiepca.txt.
621 disable_mtrr_cleanup [X86]
622 The kernel tries to adjust MTRR layout from continuous
623 to discrete, to make X server driver able to add WB
624 entry later. This parameter disables that.
626 disable_mtrr_trim [X86, Intel and AMD only]
627 By default the kernel will trim any uncacheable
628 memory out of your available memory pool based on
629 MTRR settings. This parameter disables that behavior,
630 possibly causing your machine to run very slowly.
632 disable_timer_pin_1 [X86]
633 Disable PIN 1 of APIC timer
634 Can be useful to work around chipset bugs.
636 dmasound= [HW,OSS] Sound subsystem buffers
638 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
639 this option disables the debugging code at boot.
641 dma_debug_entries=<number>
642 This option allows to tune the number of preallocated
643 entries for DMA-API debugging code. One entry is
644 required per DMA-API allocation. Use this if the
645 DMA-API debugging code disables itself because the
646 architectural default is too low.
652 dynamic_printk Enables pr_debug()/dev_dbg() calls if
653 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
654 These can also be switched on/off via
655 <debugfs>/dynamic_printk/modules
657 earlycon= [KNL] Output early console device and options.
658 uart[8250],io,<addr>[,options]
659 uart[8250],mmio,<addr>[,options]
660 Start an early, polled-mode console on the 8250/16550
661 UART at the specified I/O port or MMIO address.
662 The options are the same as for ttyS, above.
664 earlyprintk= [X86,SH,BLACKFIN]
666 earlyprintk=serial[,ttySn[,baudrate]]
669 Append ",keep" to not disable it when the real console
672 Only vga or serial or usb debug port at a time.
674 Currently only ttyS0 and ttyS1 are supported.
676 Interaction with the standard serial driver is not
679 The VGA output is eventually overwritten by the real
685 Format: {"off" | "on" | "skip[mbr]"}
687 eisa_irq_edge= [PARISC,HW]
688 See header of drivers/parisc/eisa.c.
691 See comment before function elanfreq_setup() in
692 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
695 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
696 See Documentation/block/as-iosched.txt and
697 Documentation/block/deadline-iosched.txt for details.
699 elfcorehdr= [IA64,PPC,SH,X86]
700 Specifies physical address of start of kernel core
701 image elf header. Generally kexec loader will
702 pass this option to capture kernel.
703 See Documentation/kdump/kdump.txt for details.
705 enable_mtrr_cleanup [X86]
706 The kernel tries to adjust MTRR layout from continuous
707 to discrete, to make X server driver able to add WB
708 entry later. This parameter enables that.
710 enable_timer_pin_1 [X86]
711 Enable PIN 1 of APIC timer
712 Can be useful to work around chipset bugs
713 (in particular on some ATI chipsets).
714 The kernel tries to set a reasonable default.
716 enforcing [SELINUX] Set initial enforcing status.
718 See security/selinux/Kconfig help text.
719 0 -- permissive (log only, no denials).
720 1 -- enforcing (deny and log).
722 Value can be changed at runtime via /selinux/enforce.
724 ether= [HW,NET] Ethernet cards parameters
725 This option is obsoleted by the "netdev=" option, which
726 has equivalent usage. See its documentation for details.
728 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
733 fail_make_request=[KNL]
734 General fault injection mechanism.
735 Format: <interval>,<probability>,<space>,<times>
736 See also /Documentation/fault-injection/.
739 See header of drivers/scsi/fd_mcs.c.
742 See header of drivers/scsi/fdomain.c.
745 See Documentation/blockdev/floppy.txt.
747 force_pal_cache_flush
748 [IA-64] Avoid check_sal_cache_flush which may hang on
749 buggy SAL_CACHE_FLUSH implementations. Using this
750 parameter will force ia64_sal_cache_flush to call
751 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
754 [ftrace] will set and start the specified tracer
755 as early as possible in order to facilitate early
759 [ftrace] will dump the trace buffers on oops.
762 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
763 support via parallel port (up to 5 devices per port)
764 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
765 See also Documentation/input/joystick-parport.txt
769 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
774 See header of drivers/scsi/gdth.c.
776 gpt [EFI] Forces disk with valid GPT signature but
777 invalid Protective MBR to be treated as GPT.
781 hashdist= [KNL,NUMA] Large hashes allocated during boot
782 are distributed across NUMA nodes. Defaults on
783 for 64bit NUMA, off otherwise.
784 Format: 0 | 1 (for off | on)
786 hcl= [IA-64] SGI's Hardware Graph compatibility layer
788 hd= [EIDE] (E)IDE hard drive subsystem geometry
789 Format: <cyl>,<head>,<sect>
791 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
792 size of <nn>. This works even on boxes that have no
793 highmem otherwise. This also works to reduce highmem
794 size on bigger boxes.
796 highres= [KNL] Enable/disable high resolution timer mode.
797 Valid parameters: "on", "off"
801 See Documentation/isdn/README.HiSax.
805 hpet= [X86-32,HPET] option to control HPET usage
806 Format: { enable (default) | disable | force |
808 disable: disable HPET and use PIT instead
809 force: allow force enabled of undocumented chips (ICH4,
811 verbose: show contents of HPET registers during setup
813 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
814 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
815 On x86-64 and powerpc, this option can be specified
816 multiple times interleaved with hugepages= to reserve
817 huge pages of different sizes. Valid pages sizes on
818 x86-64 are 2M (when the CPU supports "pse") and 1G
819 (when the CPU supports the "pdpe1gb" cpuinfo flag)
820 Note that 1GB pages can only be allocated at boot time
821 using hugepages= and not freed afterwards.
823 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
824 terminal devices. Valid values: 0..8
825 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
826 If specified, z/VM IUCV HVC accepts connections
827 from listed z/VM user IDs only.
829 i2c_bus= [HW] Override the default board specific I2C bus speed
830 or register an additional I2C bus that is not
831 registered from board initialization code.
835 i8042.debug [HW] Toggle i8042 debug mode
836 i8042.direct [HW] Put keyboard port into non-translated mode
837 i8042.dumbkbd [HW] Pretend that controller can only read data from
838 keyboard and cannot control its state
839 (Don't attempt to blink the leds)
840 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
841 i8042.nokbd [HW] Don't check/create keyboard port
842 i8042.noloop [HW] Disable the AUX Loopback command while probing
844 i8042.nomux [HW] Don't check presence of an active multiplexing
846 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
849 [HW] Frequency with which keyboard LEDs should blink
850 when kernel panics (default is 0.5 sec)
851 i8042.reset [HW] Reset the controller during init and cleanup
852 i8042.unlock [HW] Unlock (ignore) the keylock
856 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
857 indicates that the driver is running on unsupported
859 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
860 does not match list of supported models.
862 [HW] Report power status in /proc/i8k
863 (disabled by default)
864 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
867 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
868 See Documentation/mca.txt.
871 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
873 ide-core.nodma= [HW] (E)IDE subsystem
874 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
875 .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
876 .chs .ignore_cable are additional options
877 See Documentation/ide/ide.txt.
879 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
880 See Documentation/ide/ide.txt.
882 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
883 Claim all unknown PCI IDE storage controllers.
886 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
887 Poll forces a polling idle loop that can slightly
888 improve the performance of waking up a idle CPU, but
889 will use a lot of power and make the system run hot.
891 idle=mwait: On systems which support MONITOR/MWAIT but
892 the kernel chose to not use it because it doesn't save
893 as much power as a normal idle loop, use the
894 MONITOR/MWAIT idle loop anyways. Performance should be
895 the same as idle=poll.
896 idle=halt: Halt is forced to be used for CPU idle.
897 In such case C2/C3 won't be used again.
898 idle=nomwait: Disable mwait for CPU C-states
900 ignore_loglevel [KNL]
901 Ignore loglevel setting - this will print /all/
902 kernel messages to the console. Useful for debugging.
905 Set number of hash buckets for inode cache.
908 Format: { "0" | "1" }
909 0 -- integrity auditing messages. (Default)
910 1 -- enable informational integrity auditing messages.
913 Formt: { "sha1" | "md5" }
917 See header of drivers/scsi/in2000.c.
921 Run specified binary instead of /sbin/init as init
924 initcall_debug [KNL] Trace initcalls as they are executed. Useful
925 for working out where the kernel is dying during
928 initrd= [BOOT] Specify the location of the initial ramdisk
930 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
933 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
935 Enable intel iommu driver.
937 Disable intel iommu driver.
938 igfx_off [Default Off]
939 By default, gfx is mapped as normal device. If a gfx
940 device has a dedicated DMAR unit, the DMAR unit is
941 bypassed by not enabling DMAR with this option. In
942 this case, gfx device will use physical address for
945 With this option iommu will not optimize to look
946 for io virtual address below 32 bit forcing dual
947 address cycle on pci bus for cards supporting greater
948 than 32 bit addressing. The default is to look
949 for translation below 32 bit and if not available
950 then look in the higher range.
952 With this option on every unmap_single operation will
953 result in a hardware IOTLB flush operation as opposed
954 to batching them for performance.
958 iomem= Disable strict checking of access to MMIO memory
959 strict regions from userspace.
974 io7= [HW] IO7 for Marvel based alpha systems
975 See comment before marvel_specify_io7 in
976 arch/alpha/kernel/core_marvel.c.
978 io_delay= [X86] I/O delay method
980 Standard port 0x80 based delay
982 Alternate port 0xed based delay (needed on some systems)
984 Simple two microseconds delay
989 See Documentation/filesystems/nfsroot.txt.
991 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
992 See comment before ip2_setup() in
993 drivers/char/ip2/ip2base.c.
995 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
996 See header of drivers/scsi/ips.c.
999 When an interrupt is not handled search all handlers
1000 for it. Intended to get systems with badly broken
1004 When an interrupt is not handled search all handlers
1005 for it. Also check all handlers each timer
1006 interrupt. Intended to get systems with badly broken
1010 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1012 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1014 <cpu number>,...,<cpu number>
1016 <cpu number>-<cpu number>
1017 (must be a positive range in ascending order)
1019 <cpu number>,...,<cpu number>-<cpu number>
1021 This option can be used to specify one or more CPUs
1022 to isolate from the general SMP balancing and scheduling
1023 algorithms. You can move a process onto or off an
1024 "isolated" CPU via the CPU affinity syscalls or cpuset.
1025 <cpu number> begins at 0 and the maximum value is
1026 "number of CPUs in system - 1".
1028 This option is the preferred way to isolate CPUs. The
1029 alternative -- manually setting the CPU mask of all
1030 tasks in the system -- can cause problems and
1031 suboptimal load balancer performance.
1035 js= [HW,JOY] Analog joystick
1036 See Documentation/input/joystick.txt.
1040 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1041 specifies the amount of memory usable by the kernel
1042 for non-movable allocations. The requested amount is
1043 spread evenly throughout all nodes in the system. The
1044 remaining memory in each node is used for Movable
1045 pages. In the event, a node is too small to have both
1046 kernelcore and Movable pages, kernelcore pages will
1047 take priority and other nodes will have a larger number
1048 of kernelcore pages. The Movable zone is used for the
1049 allocation of pages that may be reclaimed or moved
1050 by the page migration subsystem. This means that
1051 HugeTLB pages may not be allocated from this zone.
1052 Note that allocations like PTEs-from-HighMem still
1053 use the HighMem zone if it exists, and the Normal
1054 zone if it does not.
1056 kgdboc= [HW] kgdb over consoles.
1057 Requires a tty driver that supports console polling.
1058 (only serial suported for now)
1059 Format: <serial_device>[,baud]
1061 kmac= [MIPS] korina ethernet MAC address.
1062 Configure the RouterBoard 532 series on-chip
1063 Ethernet adapter MAC address.
1065 kstack=N [X86] Print N words from the kernel stack
1072 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1075 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1078 libata.dma= [LIBATA] DMA control
1079 libata.dma=0 Disable all PATA and SATA DMA
1080 libata.dma=1 PATA and SATA Disk DMA only
1081 libata.dma=2 ATAPI (CDROM) DMA only
1082 libata.dma=4 Compact Flash DMA only
1083 Combinations also work, so libata.dma=3 enables DMA
1084 for disks and CDROMs, but not CFs.
1086 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1090 libata.force= [LIBATA] Force configurations. The format is comma
1091 separated list of "[ID:]VAL" where ID is
1092 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1093 matching port, link or device. Basically, it matches
1094 the ATA ID string printed on console by libata. If
1095 the whole ID part is omitted, the last PORT and DEVICE
1096 values are used. If ID hasn't been specified yet, the
1097 configuration applies to all ports, links and devices.
1099 If only DEVICE is omitted, the parameter applies to
1100 the port and all links and devices behind it. DEVICE
1101 number of 0 either selects the first device or the
1102 first fan-out link behind PMP device. It does not
1103 select the host link. DEVICE number of 15 selects the
1104 host link and device attached to it.
1106 The VAL specifies the configuration to force. As long
1107 as there's no ambiguity shortcut notation is allowed.
1108 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1109 The following configurations can be forced.
1111 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1112 Any ID with matching PORT is used.
1114 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1116 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1117 udma[/][16,25,33,44,66,100,133] notation is also
1120 * [no]ncq: Turn on or off NCQ.
1122 * nohrst, nosrst, norst: suppress hard, soft
1125 If there are multiple matching configurations changing
1126 the same attribute, the last one is used.
1128 lmb=debug [KNL] Enable lmb debug messages.
1130 load_ramdisk= [RAM] List of ramdisks to load from floppy
1131 See Documentation/blockdev/ramdisk.txt.
1133 lockd.nlm_grace_period=P [NFS] Assign grace period.
1136 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1139 lockd.nlm_timeout=T [NFS] Assign timeout value.
1142 lockd.nlm_udpport=M [NFS] Assign UDP port.
1145 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1148 loglevel= All Kernel Messages with a loglevel smaller than the
1149 console loglevel will be printed to the console. It can
1150 also be changed with klogd or other programs. The
1151 loglevels are defined as follows:
1153 0 (KERN_EMERG) system is unusable
1154 1 (KERN_ALERT) action must be taken immediately
1155 2 (KERN_CRIT) critical conditions
1156 3 (KERN_ERR) error conditions
1157 4 (KERN_WARNING) warning conditions
1158 5 (KERN_NOTICE) normal but significant condition
1159 6 (KERN_INFO) informational
1160 7 (KERN_DEBUG) debug-level messages
1162 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1163 Format: { n | nk | nM }
1164 n must be a power of two. The default size
1165 is set in the kernel config file.
1167 logo.nologo [FB] Disables display of the built-in Linux logo.
1168 This may be used to provide more screen space for
1169 kernel log messages and is useful when debugging
1170 kernel boot problems.
1172 lp=0 [LP] Specify parallel ports to use, e.g,
1173 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1174 lp=reset first parallel port). 'lp=0' disables the
1175 lp=auto printer driver. 'lp=reset' (which can be
1176 specified in addition to the ports) causes
1177 attached printers to be reset. Using
1178 lp=port1,port2,... specifies the parallel ports
1179 to associate lp devices with, starting with
1180 lp0. A port specification may be 'none' to skip
1181 that lp device, or a parport name such as
1182 'parport0'. Specifying 'lp=auto' instead of a
1183 port specification list means that device IDs
1184 from each port should be examined, to see if
1185 an IEEE 1284-compliant printer is attached; if
1186 so, the driver will manage that printer.
1187 See also header of drivers/char/lp.c.
1190 Sets loops_per_jiffy to given constant, thus avoiding
1191 time-consuming boot-time autodetection (up to 250 ms per
1192 CPU). 0 enables autodetection (default). To determine
1193 the correct value for your kernel, boot with normal
1194 autodetection and see what value is printed. Note that
1195 on SMP systems the preset will be applied to all CPUs,
1196 which is likely to cause problems if your CPUs need
1197 significantly divergent settings. An incorrect value
1198 will cause delays in the kernel to be wrong, leading to
1199 unpredictable I/O errors and other breakage. Although
1200 unlikely, in the extreme case this might damage your
1204 Format: <io>,<irq>,<dma>
1206 mac5380= [HW,SCSI] Format:
1207 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1209 machvec= [IA64] Force the use of a particular machine-vector
1210 (machvec) in a generic kernel.
1211 Example: machvec=hpzx1_swiotlb
1213 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1214 than or equal to this physical address is ignored.
1216 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1217 should make use of. maxcpus=n : n >= 0 limits the
1218 kernel to using 'n' processors. n=0 is a special case,
1219 it is equivalent to "nosmp", which also disables
1222 max_loop= [LOOP] Maximum number of loopback devices that can
1226 max_luns= [SCSI] Maximum number of LUNs to probe.
1227 Should be between 1 and 2^32-1.
1230 [SCSI] Maximum number of LUNs received.
1231 Should be between 1 and 16384.
1235 mce [X86-32] Machine Check Exception
1237 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1239 md= [HW] RAID subsystems devices and level
1240 See Documentation/md.txt.
1243 Format: <first>,<last>
1244 Specifies range of consoles to be captured by the MDA.
1246 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1247 Amount of memory to be used when the kernel is not able
1248 to see the whole system memory or for test.
1249 [X86-32] Use together with memmap= to avoid physical
1250 address space collisions. Without memmap= PCI devices
1251 could be placed at addresses belonging to unused RAM.
1253 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1257 [KNL,SH] Allow user to override the default size for
1258 per-device physically contiguous DMA buffers.
1260 memmap=exactmap [KNL,X86] Enable setting of an exact
1261 E820 memory map, as specified by the user.
1262 Such memmap=exactmap lines can be constructed based on
1263 BIOS output or other requirements. See the memmap=nn@ss
1266 memmap=nn[KMG]@ss[KMG]
1267 [KNL] Force usage of a specific region of memory
1268 Region of memory to be used, from ss to ss+nn.
1270 memmap=nn[KMG]#ss[KMG]
1271 [KNL,ACPI] Mark specific memory as ACPI data.
1272 Region of memory to be used, from ss to ss+nn.
1274 memmap=nn[KMG]$ss[KMG]
1275 [KNL,ACPI] Mark specific memory as reserved.
1276 Region of memory to be used, from ss to ss+nn.
1277 Example: Exclude memory from 0x18690000-0x1869ffff
1278 memmap=64K$0x18690000
1280 memmap=0x10000$0x18690000
1282 memory_corruption_check=0/1 [X86]
1283 Some BIOSes seem to corrupt the first 64k of
1284 memory when doing things like suspend/resume.
1285 Setting this option will scan the memory
1286 looking for corruption. Enabling this will
1287 both detect corruption and prevent the kernel
1288 from using the memory being corrupted.
1289 However, its intended as a diagnostic tool; if
1290 repeatable BIOS-originated corruption always
1291 affects the same memory, you can use memmap=
1292 to prevent the kernel from using that memory.
1294 memory_corruption_check_size=size [X86]
1295 By default it checks for corruption in the low
1296 64k, making this memory unavailable for normal
1297 use. Use this parameter to scan for
1298 corruption in more or less memory.
1300 memory_corruption_check_period=seconds [X86]
1301 By default it checks for corruption every 60
1302 seconds. Use this parameter to check at some
1303 other rate. 0 disables periodic checking.
1305 memtest= [KNL,X86] Enable memtest
1307 default : 0 <disable>
1308 Specifies the number of memtest passes to be
1309 performed. Each pass selects another test
1310 pattern from a given set of patterns. Memtest
1311 fills the memory with this pattern, validates
1312 memory contents and reserves bad memory
1313 regions that are detected.
1315 meye.*= [HW] Set MotionEye Camera parameters
1316 See Documentation/video4linux/meye.txt.
1318 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1319 Multi-Function General Purpose Timers on AMD Geode
1322 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1323 the BIOS has incorrectly applied a workaround. TinyBIOS
1324 version 0.98 is known to be affected, 0.99 fixes the
1325 problem by letting the user disable the workaround.
1329 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1330 physical address is ignored.
1333 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1334 parameter allows control of the logging verbosity for
1335 the additional memory initialisation checks. A value
1336 of 0 disables mminit logging and a level of 4 will
1337 log everything. Information is printed at KERN_DEBUG
1338 so loglevel=8 may also need to be specified.
1341 [MOUSE] Maximum time between finger touching and
1342 leaving touchpad surface for touch to be considered
1343 a tap and be reported as a left button click (for
1344 touchpads working in absolute mode only).
1346 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1347 reporting absolute coordinates, such as tablets
1348 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1349 reporting absolute coordinates, such as tablets
1351 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1352 is similar to kernelcore except it specifies the
1353 amount of memory used for migratable allocations.
1354 If both kernelcore and movablecore is specified,
1355 then kernelcore will be at *least* the specified
1356 value but may be more. If movablecore on its own
1357 is specified, the administrator must be careful
1358 that the amount of memory usable for all allocations
1364 MTD_Partition= [MTD]
1365 Format: <name>,<region-number>,<size>,<offset>
1367 MTD_Region= [MTD] Format:
1368 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1371 See drivers/mtd/cmdlinepart.c.
1374 ARM/S3C2412 JIVE boot control
1376 See arch/arm/mach-s3c2412/mach-jive.c
1378 mtouchusb.raw_coordinates=
1379 [HW] Make the MicroTouch USB driver use raw coordinates
1380 ('y', default) or cooked coordinates ('n')
1382 mtrr_chunk_size=nn[KMG] [X86]
1383 used for mtrr cleanup. It is largest continous chunk
1384 that could hold holes aka. UC entries.
1386 mtrr_gran_size=nn[KMG] [X86]
1387 Used for mtrr cleanup. It is granularity of mtrr block.
1389 Large value could prevent small alignment from
1392 mtrr_spare_reg_nr=n [X86]
1394 Range: 0,7 : spare reg number
1396 Used for mtrr cleanup. It is spare mtrr entries number.
1397 Set to 2 or more if your graphical card needs more.
1399 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1402 See header of drivers/scsi/NCR_D700.c.
1406 ncr53c400= [HW,SCSI]
1408 ncr53c400a= [HW,SCSI]
1410 ncr53c406a= [HW,SCSI]
1412 ncr53c8xx= [HW,SCSI]
1414 netdev= [NET] Network devices parameters
1415 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1416 Note that mem_start is often overloaded to mean
1417 something different and driver-specific.
1418 This usage is only documented in each driver source
1422 [NETFILTER] Enable connection tracking flow accounting
1423 0 to disable accounting
1424 1 to enable accounting
1425 Default value depends on CONFIG_NF_CT_ACCT that is
1426 going to be removed in 2.6.29.
1429 See Documentation/filesystems/nfsroot.txt.
1431 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1432 See Documentation/filesystems/nfsroot.txt.
1434 nfs.callback_tcpport=
1435 [NFS] set the TCP port on which the NFSv4 callback
1436 channel should listen.
1438 nfs.idmap_cache_timeout=
1439 [NFS] set the maximum lifetime for idmapper cache
1443 [NFS] enable 64-bit inode numbers.
1444 If zero, the NFS client will fake up a 32-bit inode
1445 number for the readdir() and stat() syscalls instead
1446 of returning the full 64-bit number.
1447 The default is to return 64-bit inode numbers.
1449 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1450 when a NMI is triggered.
1451 Format: [state][,regs][,debounce][,die]
1453 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1454 Format: [panic,][num]
1456 0 - turn nmi_watchdog off
1457 1 - use the IO-APIC timer for the NMI watchdog
1458 2 - use the local APIC for the NMI watchdog using
1459 a performance counter. Note: This will use one
1460 performance counter and the local APIC's performance
1462 When panic is specified, panic when an NMI watchdog
1464 This is useful when you use a panic=... timeout and
1465 need the box quickly up again.
1466 Instead of 1 and 2 it is possible to use the following
1467 symbolic names: lapic and ioapic
1468 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1470 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1471 emulation library even if a 387 maths coprocessor
1475 [HW] Never suspend the console
1476 Disable suspending of consoles during suspend and
1477 hibernate operations. Once disabled, debugging
1478 messages can reach various consoles while the rest
1479 of the system is being put to sleep (ie, while
1480 debugging driver suspend/resume hooks). This may
1481 not work reliably with all consoles, but is known
1482 to work with serial and VGA consoles.
1484 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1485 caches in the slab allocator. Saves per-node memory,
1486 but will impact performance.
1490 noapic [SMP,APIC] Tells the kernel to not make use of any
1491 IOAPICs that may be present in the system.
1493 nobats [PPC] Do not use BATs for mapping kernel lowmem
1494 on "Classic" PPC cores.
1498 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1500 nodelayacct [KNL] Disable per-task delay accounting
1502 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1504 nodsp [SH] Disable hardware DSP at boot time.
1506 noefi [X86] Disable EFI runtime services support.
1511 On X86-32 available only on PAE configured kernels.
1512 noexec=on: enable non-executable mappings (default)
1513 noexec=off: disable non-executable mappings
1516 This affects only 32-bit executables.
1517 noexec32=on: enable non-executable mappings (default)
1518 read doesn't imply executable mappings
1519 noexec32=off: disable non-executable mappings
1520 read implies executable mappings
1522 nofpu [SH] Disable hardware FPU at boot time.
1524 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1525 register save and restore. The kernel will only save
1526 legacy floating-point registers on task switch.
1528 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1529 wfi(ARM) instruction doesn't work correctly and not to
1530 use it. This is also useful when using JTAG debugger.
1532 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1533 instruction doesn't work correctly and not to
1536 no_file_caps Tells the kernel not to honor file capabilities. The
1537 only way then for a file to be executed with privilege
1538 is to be setuid root or executed by root.
1540 nohalt [IA-64] Tells the kernel not to use the power saving
1541 function PAL_HALT_LIGHT when idle. This increases
1542 power-consumption. On the positive side, it reduces
1543 interrupt wake-up latency, which may improve performance
1544 in certain environments such as networked servers or
1547 nohz= [KNL] Boottime enable/disable dynamic ticks
1548 Valid arguments: on, off
1551 noiotrap [SH] Disables trapped I/O port accesses.
1553 noirqdebug [X86-32] Disables the code which attempts to detect and
1554 disable unhandled interrupt sources.
1556 no_timer_check [X86,APIC] Disables the code which tests for
1557 broken timer IRQ sources.
1559 noisapnp [ISAPNP] Disables ISA PnP code.
1561 noinitrd [RAM] Tells the kernel not to load any configured
1566 nojitter [IA64] Disables jitter checking for ITC timers.
1568 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1570 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1572 noltlbs [PPC] Do not use large page/tlb entries for kernel
1573 lowmem mapping on PPC40x.
1575 nomca [IA-64] Disable machine check abort handling
1577 nomce [X86-32] Machine Check Exception
1579 nomfgpt [X86-32] Disable Multi-Function General Purpose
1580 Timer usage (for AMD Geode machines).
1582 norandmaps Don't use address space randomization. Equivalent to
1583 echo 0 > /proc/sys/kernel/randomize_va_space
1585 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1587 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1588 with UP alternatives
1590 noresidual [PPC] Don't use residual data on PReP machines.
1592 noresume [SWSUSP] Disables resume and restores original swap
1595 no-scroll [VGA] Disables scrollback.
1596 This is required for the Braillex ib80-piezo Braille
1597 reader made by F.H. Papenmeier (Germany).
1601 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1603 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1604 and disable the IO APIC. legacy for "maxcpus=0".
1606 nosoftlockup [KNL] Disable the soft-lockup detector.
1608 noswapaccount [KNL] Disable accounting of swap in memory resource
1609 controller. (See Documentation/cgroups/memory.txt)
1611 nosync [HW,M68K] Disables sync negotiation for all devices.
1613 notsc [BUGS=X86-32] Disable Time Stamp Counter
1615 nousb [USB] Disable the USB subsystem
1619 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1621 nptcg= [IA64] Override max number of concurrent global TLB
1622 purges which is reported from either PAL_VM_SUMMARY or
1625 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1627 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1628 one of ['zone', 'node', 'default'] can be specified
1629 This can be set from sysctl after boot.
1630 See Documentation/sysctl/vm.txt for details.
1632 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1633 See Documentation/debugging-via-ohci1394.txt for more
1636 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1637 Rather than timing out after 20 ms if an EC
1638 command is not properly ACKed, override the length
1639 of the timeout. We have interrupts disabled while
1640 waiting for the ACK, so if this is set too high
1641 interrupts *may* be lost!
1646 oprofile.timer= [HW]
1647 Use timer interrupt instead of performance counters
1649 osst= [HW,SCSI] SCSI Tape Driver
1650 Format: <buffer_size>,<write_threshold>
1651 See also Documentation/scsi/st.txt.
1653 panic= [KNL] Kernel behaviour on panic
1656 parkbd.port= [HW] Parallel port number the keyboard adapter is
1657 connected to, default is 0.
1659 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1660 0 for XT, 1 for AT (default is AT).
1663 parport= [HW,PPT] Specify parallel ports. 0 disables.
1664 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1665 Use 'auto' to force the driver to use any
1666 IRQ/DMA settings detected (the default is to
1667 ignore detected IRQ/DMA settings because of
1668 possible conflicts). You can specify the base
1669 address, IRQ, and DMA settings; IRQ and DMA
1670 should be numbers, or 'auto' (for using detected
1671 settings on that particular port), or 'nofifo'
1672 (to avoid using a FIFO even if it is detected).
1673 Parallel ports are assigned in the order they
1674 are specified on the command line, starting
1677 parport_init_mode= [HW,PPT]
1678 Configure VIA parallel port to operate in
1679 a specific mode. This is necessary on Pegasos
1680 computer where firmware has no options for setting
1681 up parallel port mode and sets it to spp.
1682 Currently this function knows 686a and 8231 chips.
1683 Format: [spp|ps2|epp|ecp|ecpepp]
1685 pas2= [HW,OSS] Format:
1686 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1689 See header of drivers/scsi/pas16.c.
1692 Halt all CPUs after the first oops has been printed for
1693 the specified number of seconds. This is to be used if
1694 your oopses keep scrolling off the screen.
1699 See header of drivers/block/paride/pcd.c.
1700 See also Documentation/blockdev/paride.txt.
1702 pci=option[,option...] [PCI] various PCI subsystem options:
1703 earlydump [X86] dump PCI config space before the kernel
1705 off [X86] don't probe for the PCI bus
1706 bios [X86-32] force use of PCI BIOS, don't access
1707 the hardware directly. Use this if your machine
1708 has a non-standard PCI host bridge.
1709 nobios [X86-32] disallow use of PCI BIOS, only direct
1710 hardware access methods are allowed. Use this
1711 if you experience crashes upon bootup and you
1712 suspect they are caused by the BIOS.
1713 conf1 [X86] Force use of PCI Configuration
1715 conf2 [X86] Force use of PCI Configuration
1717 noaer [PCIE] If the PCIEAER kernel config parameter is
1718 enabled, this kernel boot option can be used to
1719 disable the use of PCIE advanced error reporting.
1720 nodomains [PCI] Disable support for multiple PCI
1721 root domains (aka PCI segments, in ACPI-speak).
1722 nommconf [X86] Disable use of MMCONFIG for PCI
1724 nomsi [MSI] If the PCI_MSI kernel config parameter is
1725 enabled, this kernel boot option can be used to
1726 disable the use of MSI interrupts system-wide.
1727 noioapicquirk [APIC] Disable all boot interrupt quirks.
1728 Safety option to keep boot IRQs enabled. This
1729 should never be necessary.
1730 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1731 primary IO-APIC for bridges that cannot disable
1732 boot IRQs. This fixes a source of spurious IRQs
1733 when the system masks IRQs.
1734 noioapicreroute [APIC] Disable workaround that uses the
1735 boot IRQ equivalent of an IRQ that connects to
1736 a chipset where boot IRQs cannot be disabled.
1737 The opposite of ioapicreroute.
1738 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1739 routing table. These calls are known to be buggy
1740 on several machines and they hang the machine
1741 when used, but on other computers it's the only
1742 way to get the interrupt routing table. Try
1743 this option if the kernel is unable to allocate
1744 IRQs or discover secondary PCI buses on your
1746 rom [X86] Assign address space to expansion ROMs.
1747 Use with caution as certain devices share
1748 address decoders between ROMs and other
1750 norom [X86] Do not assign address space to
1751 expansion ROMs that do not already have
1752 BIOS assigned address ranges.
1753 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1754 assigned automatically to PCI devices. You can
1755 make the kernel exclude IRQs of your ISA cards
1757 pirqaddr=0xAAAAA [X86] Specify the physical address
1758 of the PIRQ table (normally generated
1759 by the BIOS) if it is outside the
1760 F0000h-100000h range.
1761 lastbus=N [X86] Scan all buses thru bus #N. Can be
1762 useful if the kernel is unable to find your
1763 secondary buses and you want to tell it
1764 explicitly which ones they are.
1765 assign-busses [X86] Always assign all PCI bus
1766 numbers ourselves, overriding
1767 whatever the firmware may have done.
1768 usepirqmask [X86] Honor the possible IRQ mask stored
1769 in the BIOS $PIR table. This is needed on
1770 some systems with broken BIOSes, notably
1771 some HP Pavilion N5400 and Omnibook XE3
1772 notebooks. This will have no effect if ACPI
1773 IRQ routing is enabled.
1774 noacpi [X86] Do not use ACPI for IRQ routing
1775 or for PCI scanning.
1776 use_crs [X86] Use _CRS for PCI resource
1778 routeirq Do IRQ routing for all PCI devices.
1779 This is normally done in pci_enable_device(),
1780 so this option is a temporary workaround
1781 for broken drivers that don't call it.
1782 skip_isa_align [X86] do not align io start addr, so can
1783 handle more pci cards
1784 firmware [ARM] Do not re-enumerate the bus but instead
1785 just use the configuration from the
1786 bootloader. This is currently used on
1787 IXP2000 systems where the bus has to be
1788 configured a certain way for adjunct CPUs.
1789 noearly [X86] Don't do any early type 1 scanning.
1790 This might help on some broken boards which
1791 machine check when some devices' config space
1792 is read. But various workarounds are disabled
1793 and some IOMMU drivers will not work.
1794 bfsort Sort PCI devices into breadth-first order.
1795 This sorting is done to get a device
1796 order compatible with older (<= 2.4) kernels.
1797 nobfsort Don't sort PCI devices into breadth-first order.
1798 cbiosize=nn[KMG] The fixed amount of bus space which is
1799 reserved for the CardBus bridge's IO window.
1800 The default value is 256 bytes.
1801 cbmemsize=nn[KMG] The fixed amount of bus space which is
1802 reserved for the CardBus bridge's memory
1803 window. The default value is 64 megabytes.
1806 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
1807 Specifies alignment and device to reassign
1808 aligned memory resources.
1809 If <order of align> is not specified,
1810 PAGE_SIZE is used as alignment.
1811 PCI-PCI bridge can be specified, if resource
1812 windows need to be expanded.
1814 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1817 force Enable ASPM even on devices that claim not to support it.
1818 WARNING: Forcing ASPM on may cause system lockups.
1820 pcmv= [HW,PCMCIA] BadgePAD 4
1823 See Documentation/blockdev/paride.txt.
1825 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1828 See arch/parisc/kernel/pdc_chassis.c
1831 See Documentation/blockdev/paride.txt.
1834 See Documentation/blockdev/paride.txt.
1836 pirq= [SMP,APIC] Manual mp-table setup
1837 See Documentation/x86/i386/IO-APIC.txt.
1839 plip= [PPT,NET] Parallel port network link
1840 Format: { parport<nr> | timid | 0 }
1841 See also Documentation/parport.txt.
1843 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1844 Override pmtimer IOPort with a hex value.
1848 Enable PNP debug messages. This depends on the
1849 CONFIG_PNP_DEBUG_MESSAGES option.
1855 { on | off | curr | res | no-curr | no-res }
1858 [ISAPNP] Exclude IRQs for the autoconfiguration
1861 [ISAPNP] Exclude DMAs for the autoconfiguration
1863 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1864 Ranges are in pairs (I/O port base and size).
1867 [ISAPNP] Exclude memory regions for the
1869 Ranges are in pairs (memory base and size).
1871 ports= [IP_VS_FTP] IPVS ftp helper module
1873 Up to 8 (IP_VS_APP_MAX_PORTS) ports
1875 Format: <port>,<port>....
1877 print-fatal-signals=
1878 [KNL] debug: print fatal signals
1879 print-fatal-signals=1: print segfault info to
1883 printk.time= Show timing data prefixed to each printk message line
1884 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1886 processor.max_cstate= [HW,ACPI]
1887 Limit processor to maximum C-state
1888 max_cstate=9 overrides any DMI blacklist limit.
1890 processor.nocst [HW,ACPI]
1891 Ignore the _CST method to determine C-states,
1892 instead using the legacy FADT method
1894 profile= [KNL] Enable kernel profiling via /proc/profile
1895 Format: [schedule,]<number>
1896 Param: "schedule" - profile schedule points.
1897 Param: <number> - step/bucket size as a power of 2 for
1898 statistical time based profiling.
1899 Param: "sleep" - profile D-state sleeping (millisecs).
1900 Requires CONFIG_SCHEDSTATS
1901 Param: "kvm" - profile VM exits.
1903 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1905 See Documentation/blockdev/ramdisk.txt.
1907 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1908 probe for; one of (bare|imps|exps|lifebook|any).
1909 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1911 psmouse.resetafter= [HW,MOUSE]
1912 Try to reset the device after so many bad packets
1915 [HW,MOUSE] Set desired mouse resolution, in dpi.
1916 psmouse.smartscroll=
1917 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1918 0 = disabled, 1 = enabled (default).
1920 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1922 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1925 See Documentation/blockdev/paride.txt.
1928 [KNL] Number of legacy pty's. Overwrites compiled-in
1931 quiet [KNL] Disable most log messages
1936 See Documentation/md.txt.
1938 ramdisk_blocksize= [RAM]
1939 See Documentation/blockdev/ramdisk.txt.
1941 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1942 See Documentation/blockdev/ramdisk.txt.
1944 rcupdate.blimit= [KNL,BOOT]
1945 Set maximum number of finished RCU callbacks to process
1948 rcupdate.qhimark= [KNL,BOOT]
1949 Set threshold of queued
1950 RCU callbacks over which batch limiting is disabled.
1952 rcupdate.qlowmark= [KNL,BOOT]
1953 Set threshold of queued RCU callbacks below which
1954 batch limiting is re-enabled.
1958 Run specified binary instead of /init from the ramdisk,
1959 used for early userspace startup. See initrd.
1961 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1962 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1963 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1966 [KNL, SMP] Set scheduler's default relax_domain_level.
1967 See Documentation/cgroups/cpusets.txt.
1969 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1971 reservetop= [X86-32]
1973 Reserves a hole at the top of the kernel virtual
1976 reset_devices [KNL] Force drivers to reset the underlying device
1977 during initialization.
1980 Specify the partition device for software suspend
1982 resume_offset= [SWSUSP]
1983 Specify the offset from the beginning of the partition
1984 given by "resume=" at which the swap header is located,
1985 in <PAGE_SIZE> units (needed only for swap files).
1986 See Documentation/power/swsusp-and-swap-files.txt
1988 retain_initrd [RAM] Keep initrd memory after extraction
1990 rhash_entries= [KNL,NET]
1991 Set number of hash buckets for route cache
1993 riscom8= [HW,SERIAL]
1994 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1996 ro [KNL] Mount root device read-only on boot
1998 root= [KNL] Root filesystem
2000 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2001 mount the root filesystem
2003 rootflags= [KNL] Set root filesystem mount option string
2005 rootfstype= [KNL] Set root filesystem type
2007 rootwait [KNL] Wait (indefinitely) for root device to show up.
2008 Useful for devices that are detected asynchronously
2009 (e.g. USB and MMC devices).
2011 root_plug.vendor_id=
2012 [ROOTPLUG] Override the default vendor ID
2014 root_plug.product_id=
2015 [ROOTPLUG] Override the default product ID
2018 [ROOTPLUG] Enable debugging output
2020 rw [KNL] Mount root device read-write on boot
2022 S [KNL] Run init in single mode
2025 See drivers/net/irda/sa1100_ir.c.
2027 sbni= [NET] Granch SBNI12 leased line adapter
2029 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
2030 Format: <io>[,<timeout>[,<isapnp>]]
2032 scsi_debug_*= [SCSI]
2033 See drivers/scsi/scsi_debug.c.
2035 scsi_default_dev_flags=
2036 [SCSI] SCSI default device flags
2039 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2040 Format: <vendor>:<model>:<flags>
2041 (flags are integer value)
2043 scsi_logging_level= [SCSI] a bit mask of logging levels
2044 See drivers/scsi/scsi_logging.h for bits. Also
2045 settable via sysctl at dev.scsi.logging_level
2046 (/proc/sys/dev/scsi/logging_level).
2047 There is also a nice 'scsi_logging_level' script in the
2048 S390-tools package, available for download at
2049 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2051 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2052 discovered. async scans them in kernel threads,
2053 allowing boot to proceed. none ignores them, expecting
2054 user space to do the scan.
2056 security= [SECURITY] Choose a security module to enable at boot.
2057 If this boot parameter is not specified, only the first
2058 security module asking for security registration will be
2059 loaded. An invalid security module name will be treated
2060 as if no module has been chosen.
2062 selinux= [SELINUX] Disable or enable SELinux at boot time.
2063 Format: { "0" | "1" }
2064 See security/selinux/Kconfig help text.
2067 Default value is set via kernel config option.
2068 If enabled at boot time, /selinux/disable can be used
2069 later to disable prior to initial policy load.
2071 serialnumber [BUGS=X86-32]
2074 Maximal number of shapers.
2076 show_msr= [x86] show boot-time MSR settings
2077 Format: { <integer> }
2078 Show boot-time (BIOS-initialized) MSR settings.
2079 The parameter means the number of CPUs to show,
2080 for example 1 means boot CPU only.
2083 See header of drivers/scsi/sim710.c.
2090 slub_debug[=options[,slabs]] [MM, SLUB]
2091 Enabling slub_debug allows one to determine the
2092 culprit if slab objects become corrupted. Enabling
2093 slub_debug can create guard zones around objects and
2094 may poison objects when not in use. Also tracks the
2095 last alloc / free. For more information see
2096 Documentation/vm/slub.txt.
2098 slub_max_order= [MM, SLUB]
2099 Determines the maximum allowed order for slabs.
2100 A high setting may cause OOMs due to memory
2101 fragmentation. For more information see
2102 Documentation/vm/slub.txt.
2104 slub_min_objects= [MM, SLUB]
2105 The minimum number of objects per slab. SLUB will
2106 increase the slab order up to slub_max_order to
2107 generate a sufficiently large slab able to contain
2108 the number of objects indicated. The higher the number
2109 of objects the smaller the overhead of tracking slabs
2110 and the less frequently locks need to be acquired.
2111 For more information see Documentation/vm/slub.txt.
2113 slub_min_order= [MM, SLUB]
2114 Determines the mininum page order for slabs. Must be
2115 lower than slub_max_order.
2116 For more information see Documentation/vm/slub.txt.
2118 slub_nomerge [MM, SLUB]
2119 Disable merging of slabs with similar size. May be
2120 necessary if there is some reason to distinguish
2121 allocs to different slabs. Debug options disable
2122 merging on their own.
2123 For more information see Documentation/vm/slub.txt.
2126 Format: <io1>[,<io2>[,...,<io8>]]
2128 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2129 attempt to substitute SMP alternatives once at boot.
2131 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2132 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2133 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2134 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2135 smsc-ircc2.ircc_irq= [HW] IRQ line
2136 smsc-ircc2.ircc_dma= [HW] DMA channel
2137 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2138 0: Toshiba Satellite 1800 (GP data pin select)
2139 1: Fast pin select (default)
2142 snd-ad1816a= [HW,ALSA]
2144 snd-ad1848= [HW,ALSA]
2146 snd-ali5451= [HW,ALSA]
2148 snd-als100= [HW,ALSA]
2150 snd-als4000= [HW,ALSA]
2152 snd-azt2320= [HW,ALSA]
2154 snd-cmi8330= [HW,ALSA]
2156 snd-cmipci= [HW,ALSA]
2158 snd-cs4231= [HW,ALSA]
2160 snd-cs4232= [HW,ALSA]
2162 snd-cs4236= [HW,ALSA]
2164 snd-cs4281= [HW,ALSA]
2166 snd-cs46xx= [HW,ALSA]
2168 snd-dt019x= [HW,ALSA]
2170 snd-dummy= [HW,ALSA]
2172 snd-emu10k1= [HW,ALSA]
2174 snd-ens1370= [HW,ALSA]
2176 snd-ens1371= [HW,ALSA]
2178 snd-es968= [HW,ALSA]
2180 snd-es1688= [HW,ALSA]
2182 snd-es18xx= [HW,ALSA]
2184 snd-es1938= [HW,ALSA]
2186 snd-es1968= [HW,ALSA]
2188 snd-fm801= [HW,ALSA]
2190 snd-gusclassic= [HW,ALSA]
2192 snd-gusextreme= [HW,ALSA]
2194 snd-gusmax= [HW,ALSA]
2198 snd-ice1712= [HW,ALSA]
2200 snd-intel8x0= [HW,ALSA]
2202 snd-interwave= [HW,ALSA]
2207 snd-korg1212= [HW,ALSA]
2209 snd-maestro3= [HW,ALSA]
2211 snd-mpu401= [HW,ALSA]
2213 snd-mtpav= [HW,ALSA]
2215 snd-nm256= [HW,ALSA]
2217 snd-opl3sa2= [HW,ALSA]
2225 snd-opti93x= [HW,ALSA]
2229 snd-rme32= [HW,ALSA]
2231 snd-rme96= [HW,ALSA]
2233 snd-rme9652= [HW,ALSA]
2239 snd-sbawe= [HW,ALSA]
2241 snd-serial= [HW,ALSA]
2243 snd-sgalaxy= [HW,ALSA]
2245 snd-sonicvibes= [HW,ALSA]
2250 snd-sun-cs4231= [HW,ALSA]
2252 snd-trident= [HW,ALSA]
2254 snd-usb-audio= [HW,ALSA,USB]
2256 snd-via82xx= [HW,ALSA]
2258 snd-virmidi= [HW,ALSA]
2260 snd-wavefront= [HW,ALSA]
2262 snd-ymfpci= [HW,ALSA]
2265 [KNL] Should the soft-lockup detector generate panics.
2267 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2268 See Documentation/sonypi.txt
2270 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2271 See Documentation/serial/specialix.txt.
2273 spia_io_base= [HW,MTD]
2279 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2281 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2282 See Documentation/scsi/st.txt.
2285 Enabled the stack tracer on boot up.
2289 Set the STI (builtin display/keyboard on the HP-PARISC
2290 machines) console (graphic card) which should be used
2291 as the initial boot-console.
2292 See also comment in drivers/video/console/sticore.c.
2295 See comment in drivers/video/console/sticore.c.
2298 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2302 Control how the NFS server code allocates CPUs to
2303 service thread pools. Depending on how many NICs
2304 you have and where their interrupts are bound, this
2305 option will affect which CPUs will do NFS serving.
2306 Note: this parameter cannot be changed while the
2307 NFS server is running.
2309 auto the server chooses an appropriate mode
2310 automatically using heuristics
2311 global a single global pool contains all CPUs
2312 percpu one pool for each CPU
2313 pernode one pool for each NUMA node (equivalent
2314 to global on non-NUMA machines)
2316 swiotlb= [IA-64] Number of I/O TLB slabs
2320 sym53c416= [HW,SCSI]
2321 See header of drivers/scsi/sym53c416.c.
2323 sysrq_always_enabled
2325 Ignore sysrq setting - this boot parameter will
2326 neutralize any effect of /proc/sys/kernel/sysrq.
2327 Useful for debugging.
2330 See header of drivers/scsi/t128.c.
2334 test_suspend= [SUSPEND]
2335 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2336 standby suspend) as the system sleep state to briefly
2337 enter during system startup. The system is woken from
2338 this state using a wakeup-capable RTC alarm.
2340 thash_entries= [KNL,NET]
2341 Set number of hash buckets for TCP connection
2343 thermal.act= [HW,ACPI]
2344 -1: disable all active trip points in all thermal zones
2345 <degrees C>: override all lowest active trip points
2347 thermal.crt= [HW,ACPI]
2348 -1: disable all critical trip points in all thermal zones
2349 <degrees C>: override all critical trip points
2351 thermal.nocrt= [HW,ACPI]
2352 Set to disable actions on ACPI thermal zone
2353 critical and hot trip points.
2355 thermal.off= [HW,ACPI]
2356 1: disable ACPI thermal control
2358 thermal.psv= [HW,ACPI]
2359 -1: disable all passive trip points
2360 <degrees C>: override all passive trip points to this
2363 thermal.tzp= [HW,ACPI]
2364 Specify global default ACPI thermal zone polling rate
2365 <deci-seconds>: poll all this frequency
2366 0: no polling (default)
2369 See comment before function dc390_setup() in
2370 drivers/scsi/tmscsim.c.
2374 Specify if the kernel should make use of the cpu
2375 topology informations if the hardware supports these.
2376 The scheduler will make use of these informations and
2377 e.g. base its process migration decisions on it.
2382 trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
2384 trix= [HW,OSS] MediaTrix AudioTrix Pro
2386 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2388 tsc= Disable clocksource-must-verify flag for TSC.
2390 [x86] reliable: mark tsc clocksource as reliable, this
2391 disables clocksource verification at runtime.
2392 Used to enable high-resolution timer mode on older
2393 hardware, and in virtualized environment.
2395 turbografx.map[2|3]= [HW,JOY]
2396 TurboGraFX parallel port interface
2398 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2399 See also Documentation/input/joystick-parport.txt
2401 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2402 See header of drivers/scsi/u14-34f.c.
2411 [USB] Ignore overcurrent events (default N).
2412 Some badly-designed motherboards generate lots of
2413 bogus events, for ports that aren't wired to
2414 anything. Set this parameter to avoid log spamming.
2415 Note that genuine overcurrent events won't be
2420 Set unknown_nmi_panic=1 early on boot.
2422 usbcore.autosuspend=
2423 [USB] The autosuspend time delay (in seconds) used
2424 for newly-detected USB devices (default 2). This
2425 is the time required before an idle device will be
2426 autosuspended. Devices for which the delay is set
2427 to a negative value won't be autosuspended at all.
2429 usbcore.usbfs_snoop=
2430 [USB] Set to log all usbfs traffic (default 0 = off).
2432 usbcore.blinkenlights=
2433 [USB] Set to cycle leds on hubs (default 0 = off).
2435 usbcore.old_scheme_first=
2436 [USB] Start with the old device initialization
2437 scheme (default 0 = off).
2439 usbcore.use_both_schemes=
2440 [USB] Try the other device initialization scheme
2441 if the first one fails (default 1 = enabled).
2443 usbcore.initial_descriptor_timeout=
2444 [USB] Specifies timeout for the initial 64-byte
2445 USB_REQ_GET_DESCRIPTOR request in milliseconds
2446 (default 5000 = 5.0 seconds).
2449 [USBHID] The interval which mice are to be polled at.
2451 usb-storage.delay_use=
2452 [UMS] The delay in seconds before a new device is
2453 scanned for Logical Units (default 5).
2456 [UMS] A list of quirks entries to supplement or
2457 override the built-in unusual_devs list. List
2458 entries are separated by commas. Each entry has
2459 the form VID:PID:Flags where VID and PID are Vendor
2460 and Product ID values (4-digit hex numbers) and
2461 Flags is a set of characters, each corresponding
2462 to a common usb-storage quirk flag as follows:
2463 a = SANE_SENSE (collect more than 18 bytes
2465 c = FIX_CAPACITY (decrease the reported
2466 device capacity by one sector);
2467 h = CAPACITY_HEURISTICS (decrease the
2468 reported device capacity by one
2469 sector if the number is odd);
2470 i = IGNORE_DEVICE (don't bind to this
2472 l = NOT_LOCKABLE (don't try to lock and
2473 unlock ejectable media);
2474 m = MAX_SECTORS_64 (don't transfer more
2475 than 64 sectors = 32 KB at a time);
2476 o = CAPACITY_OK (accept the capacity
2477 reported by the device);
2478 r = IGNORE_RESIDUE (the device reports
2479 bogus residue values);
2480 s = SINGLE_LUN (the device has only one
2482 w = NO_WP_DETECT (don't test whether the
2483 medium is write-protected).
2484 Example: quirks=0419:aaf5:rl,0421:0433:rc
2487 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2488 vdso=1: enable VDSO (default)
2489 vdso=0: disable VDSO mapping
2492 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2493 vdso32=1: enable 32-bit VDSO (default)
2494 vdso32=0: disable 32-bit VDSO mapping
2497 vector=percpu: enable percpu vector domain
2499 video= [FB] Frame buffer configuration
2500 See Documentation/fb/modedb.txt.
2502 vga= [BOOT,X86-32] Select a particular video mode
2503 See Documentation/x86/boot.txt and
2504 Documentation/svga.txt.
2505 Use vga=ask for menu.
2506 This is actually a boot loader parameter; the value is
2507 passed to the kernel using a special protocol.
2509 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2510 size of <nn>. This can be used to increase the
2511 minimum size (128MB on x86). It can also be used to
2512 decrease the size and leave more room for directly
2515 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2518 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2521 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2524 vt.default_blu= [VT]
2525 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2526 Change the default blue palette of the console.
2527 This is a 16-member array composed of values
2530 vt.default_grn= [VT]
2531 Format: <green0>,<green1>,<green2>,...,<green15>
2532 Change the default green palette of the console.
2533 This is a 16-member array composed of values
2536 vt.default_red= [VT]
2537 Format: <red0>,<red1>,<red2>,...,<red15>
2538 Change the default red palette of the console.
2539 This is a 16-member array composed of values
2545 Set system-wide default UTF-8 mode for all tty's.
2546 Default is 1, i.e. UTF-8 mode is enabled for all
2547 newly opened terminals.
2549 waveartist= [HW,OSS]
2550 Format: <io>,<irq>,<dma>,<dma2>
2553 See header of drivers/scsi/wd33c93.c.
2556 See header of drivers/scsi/wd7000.c.
2559 See Documentation/watchdog/wdt.txt.
2561 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2562 default x2apic cluster mode on platforms
2565 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2566 xd_geo= See header of drivers/block/xd.c.
2568 xirc2ps_cs= [NET,PCMCIA]
2570 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2572 ______________________________________________________________________
2576 Add documentation for ALSA options.
2577 Add more DRM drivers.
projects / linux-2.6 / blob