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 GCOV GCOV profiling is enabled.
52 HW Appropriate hardware is enabled.
53 IA-64 IA-64 architecture is enabled.
54 IMA Integrity measurement architecture is enabled.
55 IOSCHED More than one I/O scheduler is enabled.
56 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
57 ISAPNP ISA PnP code is enabled.
58 ISDN Appropriate ISDN support is enabled.
59 JOY Appropriate joystick support is enabled.
60 LIBATA Libata driver is enabled
61 LP Printer support is enabled.
62 LOOP Loopback device support is enabled.
63 M68k M68k architecture is enabled.
64 These options have more detailed description inside of
65 Documentation/m68k/kernel-options.txt.
66 MCA MCA bus support is enabled.
67 MDA MDA console support is enabled.
68 MOUSE Appropriate mouse support is enabled.
69 MSI Message Signaled Interrupts (PCI).
70 MTD MTD (Memory Technology Device) support is enabled.
71 NET Appropriate network support is enabled.
72 NUMA NUMA support is enabled.
73 GENERIC_TIME The generic timeofday code is enabled.
74 NFS Appropriate NFS support is enabled.
75 OSS OSS sound support is enabled.
76 PV_OPS A paravirtualized kernel is enabled.
77 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
78 PARISC The PA-RISC architecture is enabled.
79 PCI PCI bus support is enabled.
80 PCIE PCI Express support is enabled.
81 PCMCIA The PCMCIA subsystem is enabled.
82 PNP Plug & Play support is enabled.
83 PPC PowerPC architecture is enabled.
84 PPT Parallel port support is enabled.
85 PS2 Appropriate PS/2 support is enabled.
86 RAM RAM disk support is enabled.
87 ROOTPLUG The example Root Plug LSM is enabled.
88 S390 S390 architecture is enabled.
89 SCSI Appropriate SCSI support is enabled.
90 A lot of drivers has their options described inside of
92 SECURITY Different security models are enabled.
93 SELINUX SELinux support is enabled.
94 SERIAL Serial support is enabled.
95 SH SuperH architecture is enabled.
96 SMP The kernel is an SMP kernel.
97 SPARC Sparc architecture is enabled.
98 SWSUSP Software suspend (hibernation) is enabled.
99 SUSPEND System suspend states are enabled.
100 FTRACE Function tracing enabled.
101 TS Appropriate touchscreen support is enabled.
102 UMS USB Mass Storage support is enabled.
103 USB USB support is enabled.
104 USBHID USB Human Interface Device support is enabled.
105 V4L Video For Linux support is enabled.
106 VGA The VGA console has been enabled.
107 VT Virtual terminal support is enabled.
108 WDT Watchdog support is enabled.
109 XT IBM PC/XT MFM hard disk support is enabled.
110 X86-32 X86-32, aka i386 architecture is enabled.
111 X86-64 X86-64 architecture is enabled.
112 More X86-64 boot options can be found in
113 Documentation/x86/x86_64/boot-options.txt .
114 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
116 In addition, the following text indicates that the option:
118 BUGS= Relates to possible processor bugs on the said processor.
119 KNL Is a kernel start-up parameter.
120 BOOT Is a boot loader parameter.
122 Parameters denoted with BOOT are actually interpreted by the boot
123 loader, and have no meaning to the kernel directly.
124 Do not modify the syntax of boot loader parameters without extreme
125 need or coordination with <Documentation/x86/boot.txt>.
127 There are also arch-specific kernel-parameters not documented here.
128 See for example <Documentation/x86/x86_64/boot-options.txt>.
130 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
131 a trailing = on the name of any parameter states that that parameter will
132 be entered as an environment variable, whereas its absence indicates that
133 it will appear as a kernel argument readable via /proc/cmdline by programs
134 running once the system is up.
136 The number of kernel parameters is not limited, but the length of the
137 complete command line (parameters including spaces etc.) is limited to
138 a fixed number of characters. This limit depends on the architecture
139 and is between 256 and 4096 characters. It is defined in the file
140 ./include/asm/setup.h as COMMAND_LINE_SIZE.
144 Advanced Configuration and Power Interface
145 Format: { force | off | ht | strict | noirq | rsdt }
146 force -- enable ACPI if default was off
147 off -- disable ACPI if default was on
148 noirq -- do not use ACPI for IRQ routing
149 ht -- run only enough ACPI to enable Hyper Threading
150 strict -- Be less tolerant of platforms that are not
151 strictly ACPI specification compliant.
152 rsdt -- prefer RSDT over (default) XSDT
154 See also Documentation/power/pm.txt, pci=noacpi
156 acpi_apic_instance= [ACPI, IOAPIC]
158 2: use 2nd APIC table, if available
159 1,0: use 1st APIC table
162 acpi_backlight= [HW,ACPI]
163 acpi_backlight=vendor
165 If set to vendor, prefer vendor specific driver
166 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
167 of the ACPI video.ko driver.
169 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
170 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
172 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
173 debug output. Bits in debug_layer correspond to a
174 _COMPONENT in an ACPI source file, e.g.,
175 #define _COMPONENT ACPI_PCI_COMPONENT
176 Bits in debug_level correspond to a level in
177 ACPI_DEBUG_PRINT statements, e.g.,
178 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
179 The debug_level mask defaults to "info". See
180 Documentation/acpi/debug.txt for more information about
181 debug layers and levels.
183 Enable processor driver info messages:
184 acpi.debug_layer=0x20000000
185 Enable PCI/PCI interrupt routing info messages:
186 acpi.debug_layer=0x400000
187 Enable AML "Debug" output, i.e., stores to the Debug
188 object while interpreting AML:
189 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
190 Enable all messages related to ACPI hardware:
191 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
193 Some values produce so much output that the system is
194 unusable. The "log_buf_len" parameter may be useful
195 if you need to capture more output.
197 acpi_display_output= [HW,ACPI]
198 acpi_display_output=vendor
199 acpi_display_output=video
202 acpi_irq_balance [HW,ACPI]
203 ACPI will balance active IRQs
206 acpi_irq_nobalance [HW,ACPI]
207 ACPI will not move active IRQs (default)
210 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
211 Format: <irq>,<irq>...
213 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
215 Format: <irq>,<irq>...
217 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
219 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
220 Format: To spoof as Windows 98: ="Microsoft Windows"
222 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
223 acpi_osi="string1" # add string1 -- only one string
224 acpi_osi="!string2" # remove built-in string2
225 acpi_osi= # disable all strings
228 Override the pmtimer bug detection: force the kernel
229 to assume that this machine's pmtimer latches its value
230 and always returns good values.
232 acpi.power_nocheck= [HW,ACPI]
233 Format: 1/0 enable/disable the check of power state.
234 On some bogus BIOS the _PSC object/_STA object of
235 power resource can't return the correct device power
236 state. In such case it is unneccessary to check its
237 power state again in power transition.
238 1 : disable the power state check
240 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
241 Format: { level | edge | high | low }
243 acpi_serialize [HW,ACPI] force serialization of AML methods
245 acpi_skip_timer_override [HW,ACPI]
246 Recognize and ignore IRQ0/pin2 Interrupt Override.
247 For broken nForce2 BIOS resulting in XT-PIC timer.
249 acpi_sleep= [HW,ACPI] Sleep options
250 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
251 old_ordering, s4_nonvs }
252 See Documentation/power/video.txt for information on
254 s3_beep is for debugging; it makes the PC's speaker beep
255 as soon as the kernel's real-mode entry point is called.
256 s4_nohwsig prevents ACPI hardware signature from being
257 used during resume from hibernation.
258 old_ordering causes the ACPI 1.0 ordering of the _PTS
259 control method, with respect to putting devices into
260 low power states, to be enforced (the ACPI 2.0 ordering
261 of _PTS is used by default).
262 s4_nonvs prevents the kernel from saving/restoring the
263 ACPI NVS memory during hibernation.
265 acpi_use_timer_override [HW,ACPI]
266 Use timer override. For some broken Nvidia NF5 boards
267 that require a timer override, but don't have HPET
269 acpi_enforce_resources= [ACPI]
270 { strict | lax | no }
271 Check for resource conflicts between native drivers
272 and ACPI OperationRegions (SystemIO and SystemMemory
273 only). IO ports and memory declared in ACPI might be
274 used by the ACPI subsystem in arbitrary AML code and
275 can interfere with legacy drivers.
276 strict (default): access to resources claimed by ACPI
277 is denied; legacy drivers trying to access reserved
278 resources will fail to bind to device using them.
279 lax: access to resources claimed by ACPI is allowed;
280 legacy drivers trying to access reserved resources
281 will bind successfully but a warning message is logged.
282 no: ACPI OperationRegions are not marked as reserved,
283 no further checks are performed.
286 Format: <io>,<irq>,<dma>,<dma2>,<type>
288 add_efi_memmap [EFI; X86] Include EFI memory map in
289 kernel's map of available physical RAM.
292 See header of drivers/scsi/advansys.c.
294 advwdt= [HW,WDT] Advantech WDT
295 Format: <iostart>,<iostop>
297 aedsp16= [HW,OSS] Audio Excel DSP 16
298 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
299 See also header of sound/oss/aedsp16.c.
302 { off | try_unsupported }
303 off: disable AGP support
304 try_unsupported: try to drive unsupported chipsets
305 (may crash computer or cause data corruption)
308 See Documentation/scsi/aha152x.txt.
311 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
314 See Documentation/scsi/aic7xxx.txt.
317 See Documentation/scsi/aic79xx.txt.
319 amd_iommu= [HW,X86-84]
320 Pass parameters to the AMD IOMMU driver in the system.
322 isolate - enable device isolation (each device, as far
323 as possible, will get its own protection
325 share - put every device behind one IOMMU into the
326 same protection domain
327 fullflush - enable flushing of IO/TLB entries when
328 they are unmapped. Otherwise they are
329 flushed before they will be reused, which
332 amijoy.map= [HW,JOY] Amiga joystick support
333 Map of devices attached to JOY0DAT and JOY1DAT
335 See also Documentation/kernel/input/joystick.txt
337 analog.map= [HW,JOY] Analog joystick and gamepad support
338 Specifies type or capabilities of an analog joystick
339 connected to one of 16 gameports
340 Format: <type1>,<type2>,..<type16>
343 Power management functions (SPARCstation-4/5 + deriv.)
345 Disable APC CPU standby support. SPARCstation-Fox does
346 not play well with APC CPU idle - disable it if you have
347 APC and your system crashes randomly.
349 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
350 Change the output verbosity whilst booting
351 Format: { quiet (default) | verbose | debug }
352 Change the amount of debugging information output
353 when initialising the APIC and IO-APIC components.
355 apm= [APM] Advanced Power Management
356 See header of arch/x86/kernel/apm_32.c.
358 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
359 Format: <io>,<irq>,<nodeID>
363 atarimouse= [HW,MOUSE] Atari Mouse
365 atascsi= [HW,SCSI] Atari SCSI
367 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
368 EzKey and similar keyboards
370 atkbd.reset= [HW] Reset keyboard during initialization
372 atkbd.set= [HW] Select keyboard code set
373 Format: <int> (2 = AT (default), 3 = PS/2)
375 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
378 atkbd.softraw= [HW] Choose between synthetic and real raw mode
379 Format: <bool> (0 = real, 1 = synthetic (default))
381 atkbd.softrepeat= [HW]
382 Use software keyboard repeat
386 baycom_epp= [HW,AX25]
389 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
391 See header of drivers/net/hamradio/baycom_par.c.
393 baycom_ser_fdx= [HW,AX25]
394 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
395 Format: <io>,<irq>,<mode>[,<baud>]
396 See header of drivers/net/hamradio/baycom_ser_fdx.c.
398 baycom_ser_hdx= [HW,AX25]
399 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
400 Format: <io>,<irq>,<mode>
401 See header of drivers/net/hamradio/baycom_ser_hdx.c.
403 boot_delay= Milliseconds to delay each printk during boot.
404 Values larger than 10 seconds (10000) are changed to
408 bootmem_debug [KNL] Enable bootmem allocator debug messages.
410 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
411 bttv.radio= Most important insmod options are available as
413 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
414 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
417 See drivers/scsi/BusLogic.c, comment before function
418 BusLogic_ParseDriverOptions().
420 c101= [NET] Moxa C101 synchronous serial card
422 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
423 Sometimes CPU hardware bugs make them report the cache
424 size incorrectly. The kernel will attempt work arounds
425 to fix known problems, but for some CPUs it is not
426 possible to determine what the correct size should be.
427 This option provides an override for these situations.
430 [SECURITY] Disable capabilities. This would normally
431 be used only if an alternative security model is to be
432 configured. Potentially dangerous and should only be
433 used if you are entirely sure of the consequences.
435 ccw_timeout_log [S390]
436 See Documentation/s390/CommonIO for details.
438 cgroup_disable= [KNL] Disable a particular controller
439 Format: {name of the controller(s) to disable}
440 {Currently supported controllers - "memory"}
442 checkreqprot [SELINUX] Set initial checkreqprot flag value.
443 Format: { "0" | "1" }
444 See security/selinux/Kconfig help text.
445 0 -- check protection applied by kernel (includes
446 any implied execute protection).
447 1 -- check protection requested by application.
448 Default value is set via a kernel config option.
449 Value can be changed at runtime via
450 /selinux/checkreqprot.
453 See Documentation/s390/CommonIO for details.
455 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
457 Forces specified clocksource (if available) to be used
458 when calculating gettimeofday(). If specified
459 clocksource is not available, it defaults to PIT.
460 Format: { pit | tsc | cyclone | pmtmr }
462 clocksource= [GENERIC_TIME] Override the default clocksource
464 Override the default clocksource and use the clocksource
465 with the name specified.
466 Some clocksource names to choose from, depending on
468 [all] jiffies (this is the base, fallback clocksource)
470 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
471 pxa_timer,timer3,32k_counter,timer0_1
473 [X86-32] pit,hpet,tsc,vmi-timer;
474 scx200_hrt on Geode; cyclone on IBM x440
482 clearcpuid=BITNUM [X86]
483 Disable CPUID feature X for the kernel. See
484 arch/x86/include/asm/cpufeature.h for the valid bit
485 numbers. Note the Linux specific bits are not necessarily
486 stable over kernel options, but the vendor specific
488 Also note that user programs calling CPUID directly
489 or using the feature without checking anything
490 will still see it. This just prevents it from
491 being used by the kernel or shown in /proc/cpuinfo.
492 Also note the kernel might malfunction if you disable
495 cmo_free_hint= [PPC] Format: { yes | no }
496 Specify whether pages are marked as being inactive
497 when they are freed. This is used in CMO environments
498 to determine OS memory pressure for page stealing by
502 code_bytes [X86] How many bytes of object code to print
507 com20020= [HW,NET] ARCnet - COM20020 chipset
509 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
511 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
515 ARCnet - COM90xx chipset (memory-mapped buffers)
516 Format: <io>[,<irq>[,<memstart>]]
518 condev= [HW,S390] console device
521 console= [KNL] Output console device and options.
523 tty<n> Use the virtual console device <n>.
527 Use the specified serial port. The options are of
528 the form "bbbbpnf", where "bbbb" is the baud rate,
529 "p" is parity ("n", "o", or "e"), "n" is number of
530 bits, and "f" is flow control ("r" for RTS or
531 omit it). Default is "9600n8".
533 See Documentation/serial-console.txt for more
535 Documentation/networking/netconsole.txt for an
538 uart[8250],io,<addr>[,options]
539 uart[8250],mmio,<addr>[,options]
540 Start an early, polled-mode console on the 8250/16550
541 UART at the specified I/O port or MMIO address,
542 switching to the matching ttyS device later. The
543 options are the same as for ttyS, above.
545 If the device connected to the port is not a TTY but a braille
546 device, prepend "brl," before the device type, for instance
548 For now, only VisioBraille is supported.
550 consoleblank= [KNL] The console blank (screen saver) timeout in
551 seconds. Defaults to 10*60 = 10mins. A value of 0
552 disables the blank timer.
555 [KNL] Change the default value for
556 /proc/<pid>/coredump_filter.
557 See also Documentation/filesystems/proc.txt.
559 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
561 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
563 crashkernel=nn[KMG]@ss[KMG]
564 [KNL] Reserve a chunk of physical memory to
565 hold a kernel to switch to with kexec on panic.
567 crashkernel=range1:size1[,range2:size2,...][@offset]
568 [KNL] Same as above, but depends on the memory
569 in the running system. The syntax of range is
570 start-[end] where start and end are both
571 a memory unit (amount[KMG]). See also
572 Documentation/kdump/kdump.txt for a example.
577 cs89x0_media= [HW,NET]
578 Format: { rj45 | aui | bnc }
581 See header of drivers/s390/block/dasd_devmap.c.
583 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
584 (one device per port)
585 Format: <port#>,<type>
586 See also Documentation/input/joystick-parport.txt
588 debug [KNL] Enable kernel debugging (events log level).
591 [KNL] verbose self-tests
593 Print debugging info while doing the locking API
595 We default to 0 (no extra messages), setting it to
596 1 will print _a lot_ more information - normally
597 only useful to kernel developers.
599 debug_objects [KNL] Enable object debugging
602 [KNL] Disable object debugging
604 debugpat [X86] Enable PAT debugging
606 decnet.addr= [HW,NET]
607 Format: <area>[,<node>]
608 See also Documentation/networking/decnet.txt.
611 [same as hugepagesz=] The size of the default
612 HugeTLB page size. This is the size represented by
613 the legacy /proc/ hugepages APIs, used for SHM, and
614 default size when mounting hugetlbfs filesystems.
615 Defaults to the default architecture's huge page size
619 Set number of hash buckets for dentry cache.
622 IO parameters + enable/disable command.
624 digiepca= [HW,SERIAL]
625 See drivers/char/README.epca and
626 Documentation/serial/digiepca.txt.
628 disable_mtrr_cleanup [X86]
629 The kernel tries to adjust MTRR layout from continuous
630 to discrete, to make X server driver able to add WB
631 entry later. This parameter disables that.
633 disable_mtrr_trim [X86, Intel and AMD only]
634 By default the kernel will trim any uncacheable
635 memory out of your available memory pool based on
636 MTRR settings. This parameter disables that behavior,
637 possibly causing your machine to run very slowly.
639 disable_timer_pin_1 [X86]
640 Disable PIN 1 of APIC timer
641 Can be useful to work around chipset bugs.
643 dmasound= [HW,OSS] Sound subsystem buffers
645 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
646 this option disables the debugging code at boot.
648 dma_debug_entries=<number>
649 This option allows to tune the number of preallocated
650 entries for DMA-API debugging code. One entry is
651 required per DMA-API allocation. Use this if the
652 DMA-API debugging code disables itself because the
653 architectural default is too low.
655 dma_debug_driver=<driver_name>
656 With this option the DMA-API debugging driver
657 filter feature can be enabled at boot time. Just
658 pass the driver to filter for as the parameter.
659 The filter can be disabled or changed to another
660 driver later using sysfs.
666 dynamic_printk Enables pr_debug()/dev_dbg() calls if
667 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
668 These can also be switched on/off via
669 <debugfs>/dynamic_printk/modules
671 earlycon= [KNL] Output early console device and options.
672 uart[8250],io,<addr>[,options]
673 uart[8250],mmio,<addr>[,options]
674 Start an early, polled-mode console on the 8250/16550
675 UART at the specified I/O port or MMIO address.
676 The options are the same as for ttyS, above.
678 earlyprintk= [X86,SH,BLACKFIN]
680 earlyprintk=serial[,ttySn[,baudrate]]
683 Append ",keep" to not disable it when the real console
686 Only vga or serial or usb debug port at a time.
688 Currently only ttyS0 and ttyS1 are supported.
690 Interaction with the standard serial driver is not
693 The VGA output is eventually overwritten by the real
699 Format: {"off" | "on" | "skip[mbr]"}
701 eisa_irq_edge= [PARISC,HW]
702 See header of drivers/parisc/eisa.c.
705 See comment before function elanfreq_setup() in
706 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
709 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
710 See Documentation/block/as-iosched.txt and
711 Documentation/block/deadline-iosched.txt for details.
713 elfcorehdr= [IA64,PPC,SH,X86]
714 Specifies physical address of start of kernel core
715 image elf header. Generally kexec loader will
716 pass this option to capture kernel.
717 See Documentation/kdump/kdump.txt for details.
719 enable_mtrr_cleanup [X86]
720 The kernel tries to adjust MTRR layout from continuous
721 to discrete, to make X server driver able to add WB
722 entry later. This parameter enables that.
724 enable_timer_pin_1 [X86]
725 Enable PIN 1 of APIC timer
726 Can be useful to work around chipset bugs
727 (in particular on some ATI chipsets).
728 The kernel tries to set a reasonable default.
730 enforcing [SELINUX] Set initial enforcing status.
732 See security/selinux/Kconfig help text.
733 0 -- permissive (log only, no denials).
734 1 -- enforcing (deny and log).
736 Value can be changed at runtime via /selinux/enforce.
738 ether= [HW,NET] Ethernet cards parameters
739 This option is obsoleted by the "netdev=" option, which
740 has equivalent usage. See its documentation for details.
742 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
747 fail_make_request=[KNL]
748 General fault injection mechanism.
749 Format: <interval>,<probability>,<space>,<times>
750 See also /Documentation/fault-injection/.
753 See header of drivers/scsi/fd_mcs.c.
756 See header of drivers/scsi/fdomain.c.
759 See Documentation/blockdev/floppy.txt.
761 force_pal_cache_flush
762 [IA-64] Avoid check_sal_cache_flush which may hang on
763 buggy SAL_CACHE_FLUSH implementations. Using this
764 parameter will force ia64_sal_cache_flush to call
765 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
768 [FTRACE] will set and start the specified tracer
769 as early as possible in order to facilitate early
773 [FTRACE] will dump the trace buffers on oops.
775 ftrace_filter=[function-list]
776 [FTRACE] Limit the functions traced by the function
777 tracer at boot up. function-list is a comma separated
778 list of functions. This list can be changed at run
779 time by the set_ftrace_filter file in the debugfs
782 ftrace_notrace=[function-list]
783 [FTRACE] Do not trace the functions specified in
784 function-list. This list can be changed at run time
785 by the set_ftrace_notrace file in the debugfs
789 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
790 support via parallel port (up to 5 devices per port)
791 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
792 See also Documentation/input/joystick-parport.txt
796 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
800 gcov_persist= [GCOV] When non-zero (default), profiling data for
801 kernel modules is saved and remains accessible via
802 debugfs, even when the module is unloaded/reloaded.
803 When zero, profiling data is discarded and associated
804 debugfs files are removed at module unload time.
807 See header of drivers/scsi/gdth.c.
809 gpt [EFI] Forces disk with valid GPT signature but
810 invalid Protective MBR to be treated as GPT.
814 hashdist= [KNL,NUMA] Large hashes allocated during boot
815 are distributed across NUMA nodes. Defaults on
816 for 64bit NUMA, off otherwise.
817 Format: 0 | 1 (for off | on)
819 hcl= [IA-64] SGI's Hardware Graph compatibility layer
821 hd= [EIDE] (E)IDE hard drive subsystem geometry
822 Format: <cyl>,<head>,<sect>
824 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
825 size of <nn>. This works even on boxes that have no
826 highmem otherwise. This also works to reduce highmem
827 size on bigger boxes.
829 highres= [KNL] Enable/disable high resolution timer mode.
830 Valid parameters: "on", "off"
834 See Documentation/isdn/README.HiSax.
838 hpet= [X86-32,HPET] option to control HPET usage
839 Format: { enable (default) | disable | force |
841 disable: disable HPET and use PIT instead
842 force: allow force enabled of undocumented chips (ICH4,
844 verbose: show contents of HPET registers during setup
846 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
847 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
848 On x86-64 and powerpc, this option can be specified
849 multiple times interleaved with hugepages= to reserve
850 huge pages of different sizes. Valid pages sizes on
851 x86-64 are 2M (when the CPU supports "pse") and 1G
852 (when the CPU supports the "pdpe1gb" cpuinfo flag)
853 Note that 1GB pages can only be allocated at boot time
854 using hugepages= and not freed afterwards.
856 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
857 terminal devices. Valid values: 0..8
858 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
859 If specified, z/VM IUCV HVC accepts connections
860 from listed z/VM user IDs only.
862 i2c_bus= [HW] Override the default board specific I2C bus speed
863 or register an additional I2C bus that is not
864 registered from board initialization code.
868 i8042.debug [HW] Toggle i8042 debug mode
869 i8042.direct [HW] Put keyboard port into non-translated mode
870 i8042.dumbkbd [HW] Pretend that controller can only read data from
871 keyboard and cannot control its state
872 (Don't attempt to blink the leds)
873 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
874 i8042.nokbd [HW] Don't check/create keyboard port
875 i8042.noloop [HW] Disable the AUX Loopback command while probing
877 i8042.nomux [HW] Don't check presence of an active multiplexing
879 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
882 [HW] Frequency with which keyboard LEDs should blink
883 when kernel panics (default is 0.5 sec)
884 i8042.reset [HW] Reset the controller during init and cleanup
885 i8042.unlock [HW] Unlock (ignore) the keylock
889 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
890 indicates that the driver is running on unsupported
892 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
893 does not match list of supported models.
895 [HW] Report power status in /proc/i8k
896 (disabled by default)
897 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
900 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
901 See Documentation/mca.txt.
904 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
906 ide-core.nodma= [HW] (E)IDE subsystem
907 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
908 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
909 .cdrom .chs .ignore_cable are additional options
910 See Documentation/ide/ide.txt.
912 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
913 Claim all unknown PCI IDE storage controllers.
916 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
917 Poll forces a polling idle loop that can slightly
918 improve the performance of waking up a idle CPU, but
919 will use a lot of power and make the system run hot.
921 idle=mwait: On systems which support MONITOR/MWAIT but
922 the kernel chose to not use it because it doesn't save
923 as much power as a normal idle loop, use the
924 MONITOR/MWAIT idle loop anyways. Performance should be
925 the same as idle=poll.
926 idle=halt: Halt is forced to be used for CPU idle.
927 In such case C2/C3 won't be used again.
928 idle=nomwait: Disable mwait for CPU C-states
930 ignore_loglevel [KNL]
931 Ignore loglevel setting - this will print /all/
932 kernel messages to the console. Useful for debugging.
935 Set number of hash buckets for inode cache.
938 Format: { "0" | "1" }
939 0 -- integrity auditing messages. (Default)
940 1 -- enable informational integrity auditing messages.
943 Formt: { "sha1" | "md5" }
947 Load a policy which meets the needs of the Trusted
948 Computing Base. This means IMA will measure all
949 programs exec'd, files mmap'd for exec, and all files
950 opened for read by uid=0.
953 See header of drivers/scsi/in2000.c.
957 Run specified binary instead of /sbin/init as init
960 initcall_debug [KNL] Trace initcalls as they are executed. Useful
961 for working out where the kernel is dying during
964 initrd= [BOOT] Specify the location of the initial ramdisk
966 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
969 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
971 Enable intel iommu driver.
973 Disable intel iommu driver.
974 igfx_off [Default Off]
975 By default, gfx is mapped as normal device. If a gfx
976 device has a dedicated DMAR unit, the DMAR unit is
977 bypassed by not enabling DMAR with this option. In
978 this case, gfx device will use physical address for
981 With this option iommu will not optimize to look
982 for io virtual address below 32 bit forcing dual
983 address cycle on pci bus for cards supporting greater
984 than 32 bit addressing. The default is to look
985 for translation below 32 bit and if not available
986 then look in the higher range.
988 With this option on every unmap_single operation will
989 result in a hardware IOTLB flush operation as opposed
990 to batching them for performance.
994 iomem= Disable strict checking of access to MMIO memory
995 strict regions from userspace.
1010 io7= [HW] IO7 for Marvel based alpha systems
1011 See comment before marvel_specify_io7 in
1012 arch/alpha/kernel/core_marvel.c.
1014 io_delay= [X86] I/O delay method
1016 Standard port 0x80 based delay
1018 Alternate port 0xed based delay (needed on some systems)
1020 Simple two microseconds delay
1025 See Documentation/filesystems/nfsroot.txt.
1027 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1028 See comment before ip2_setup() in
1029 drivers/char/ip2/ip2base.c.
1031 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
1032 See header of drivers/scsi/ips.c.
1035 When an interrupt is not handled search all handlers
1036 for it. Intended to get systems with badly broken
1040 When an interrupt is not handled search all handlers
1041 for it. Also check all handlers each timer
1042 interrupt. Intended to get systems with badly broken
1046 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1048 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1050 <cpu number>,...,<cpu number>
1052 <cpu number>-<cpu number>
1053 (must be a positive range in ascending order)
1055 <cpu number>,...,<cpu number>-<cpu number>
1057 This option can be used to specify one or more CPUs
1058 to isolate from the general SMP balancing and scheduling
1059 algorithms. You can move a process onto or off an
1060 "isolated" CPU via the CPU affinity syscalls or cpuset.
1061 <cpu number> begins at 0 and the maximum value is
1062 "number of CPUs in system - 1".
1064 This option is the preferred way to isolate CPUs. The
1065 alternative -- manually setting the CPU mask of all
1066 tasks in the system -- can cause problems and
1067 suboptimal load balancer performance.
1071 js= [HW,JOY] Analog joystick
1072 See Documentation/input/joystick.txt.
1076 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1077 specifies the amount of memory usable by the kernel
1078 for non-movable allocations. The requested amount is
1079 spread evenly throughout all nodes in the system. The
1080 remaining memory in each node is used for Movable
1081 pages. In the event, a node is too small to have both
1082 kernelcore and Movable pages, kernelcore pages will
1083 take priority and other nodes will have a larger number
1084 of kernelcore pages. The Movable zone is used for the
1085 allocation of pages that may be reclaimed or moved
1086 by the page migration subsystem. This means that
1087 HugeTLB pages may not be allocated from this zone.
1088 Note that allocations like PTEs-from-HighMem still
1089 use the HighMem zone if it exists, and the Normal
1090 zone if it does not.
1092 kgdboc= [HW] kgdb over consoles.
1093 Requires a tty driver that supports console polling.
1094 (only serial supported for now)
1095 Format: <serial_device>[,baud]
1097 kmac= [MIPS] korina ethernet MAC address.
1098 Configure the RouterBoard 532 series on-chip
1099 Ethernet adapter MAC address.
1101 kmemleak= [KNL] Boot-time kmemleak enable/disable
1102 Valid arguments: on, off
1105 kstack=N [X86] Print N words from the kernel stack
1112 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1115 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1118 libata.dma= [LIBATA] DMA control
1119 libata.dma=0 Disable all PATA and SATA DMA
1120 libata.dma=1 PATA and SATA Disk DMA only
1121 libata.dma=2 ATAPI (CDROM) DMA only
1122 libata.dma=4 Compact Flash DMA only
1123 Combinations also work, so libata.dma=3 enables DMA
1124 for disks and CDROMs, but not CFs.
1126 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1130 libata.force= [LIBATA] Force configurations. The format is comma
1131 separated list of "[ID:]VAL" where ID is
1132 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1133 matching port, link or device. Basically, it matches
1134 the ATA ID string printed on console by libata. If
1135 the whole ID part is omitted, the last PORT and DEVICE
1136 values are used. If ID hasn't been specified yet, the
1137 configuration applies to all ports, links and devices.
1139 If only DEVICE is omitted, the parameter applies to
1140 the port and all links and devices behind it. DEVICE
1141 number of 0 either selects the first device or the
1142 first fan-out link behind PMP device. It does not
1143 select the host link. DEVICE number of 15 selects the
1144 host link and device attached to it.
1146 The VAL specifies the configuration to force. As long
1147 as there's no ambiguity shortcut notation is allowed.
1148 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1149 The following configurations can be forced.
1151 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1152 Any ID with matching PORT is used.
1154 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1156 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1157 udma[/][16,25,33,44,66,100,133] notation is also
1160 * [no]ncq: Turn on or off NCQ.
1162 * nohrst, nosrst, norst: suppress hard, soft
1165 If there are multiple matching configurations changing
1166 the same attribute, the last one is used.
1168 lmb=debug [KNL] Enable lmb debug messages.
1170 load_ramdisk= [RAM] List of ramdisks to load from floppy
1171 See Documentation/blockdev/ramdisk.txt.
1173 lockd.nlm_grace_period=P [NFS] Assign grace period.
1176 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1179 lockd.nlm_timeout=T [NFS] Assign timeout value.
1182 lockd.nlm_udpport=M [NFS] Assign UDP port.
1185 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1188 loglevel= All Kernel Messages with a loglevel smaller than the
1189 console loglevel will be printed to the console. It can
1190 also be changed with klogd or other programs. The
1191 loglevels are defined as follows:
1193 0 (KERN_EMERG) system is unusable
1194 1 (KERN_ALERT) action must be taken immediately
1195 2 (KERN_CRIT) critical conditions
1196 3 (KERN_ERR) error conditions
1197 4 (KERN_WARNING) warning conditions
1198 5 (KERN_NOTICE) normal but significant condition
1199 6 (KERN_INFO) informational
1200 7 (KERN_DEBUG) debug-level messages
1202 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1203 Format: { n | nk | nM }
1204 n must be a power of two. The default size
1205 is set in the kernel config file.
1207 logo.nologo [FB] Disables display of the built-in Linux logo.
1208 This may be used to provide more screen space for
1209 kernel log messages and is useful when debugging
1210 kernel boot problems.
1212 lp=0 [LP] Specify parallel ports to use, e.g,
1213 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1214 lp=reset first parallel port). 'lp=0' disables the
1215 lp=auto printer driver. 'lp=reset' (which can be
1216 specified in addition to the ports) causes
1217 attached printers to be reset. Using
1218 lp=port1,port2,... specifies the parallel ports
1219 to associate lp devices with, starting with
1220 lp0. A port specification may be 'none' to skip
1221 that lp device, or a parport name such as
1222 'parport0'. Specifying 'lp=auto' instead of a
1223 port specification list means that device IDs
1224 from each port should be examined, to see if
1225 an IEEE 1284-compliant printer is attached; if
1226 so, the driver will manage that printer.
1227 See also header of drivers/char/lp.c.
1230 Sets loops_per_jiffy to given constant, thus avoiding
1231 time-consuming boot-time autodetection (up to 250 ms per
1232 CPU). 0 enables autodetection (default). To determine
1233 the correct value for your kernel, boot with normal
1234 autodetection and see what value is printed. Note that
1235 on SMP systems the preset will be applied to all CPUs,
1236 which is likely to cause problems if your CPUs need
1237 significantly divergent settings. An incorrect value
1238 will cause delays in the kernel to be wrong, leading to
1239 unpredictable I/O errors and other breakage. Although
1240 unlikely, in the extreme case this might damage your
1244 Format: <io>,<irq>,<dma>
1246 mac5380= [HW,SCSI] Format:
1247 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1249 machvec= [IA64] Force the use of a particular machine-vector
1250 (machvec) in a generic kernel.
1251 Example: machvec=hpzx1_swiotlb
1253 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1254 than or equal to this physical address is ignored.
1256 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1257 should make use of. maxcpus=n : n >= 0 limits the
1258 kernel to using 'n' processors. n=0 is a special case,
1259 it is equivalent to "nosmp", which also disables
1262 max_loop= [LOOP] Maximum number of loopback devices that can
1266 max_luns= [SCSI] Maximum number of LUNs to probe.
1267 Should be between 1 and 2^32-1.
1270 [SCSI] Maximum number of LUNs received.
1271 Should be between 1 and 16384.
1275 mce [X86-32] Machine Check Exception
1277 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1279 md= [HW] RAID subsystems devices and level
1280 See Documentation/md.txt.
1283 Format: <first>,<last>
1284 Specifies range of consoles to be captured by the MDA.
1286 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1287 Amount of memory to be used when the kernel is not able
1288 to see the whole system memory or for test.
1289 [X86-32] Use together with memmap= to avoid physical
1290 address space collisions. Without memmap= PCI devices
1291 could be placed at addresses belonging to unused RAM.
1293 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1297 [KNL,SH] Allow user to override the default size for
1298 per-device physically contiguous DMA buffers.
1300 memmap=exactmap [KNL,X86] Enable setting of an exact
1301 E820 memory map, as specified by the user.
1302 Such memmap=exactmap lines can be constructed based on
1303 BIOS output or other requirements. See the memmap=nn@ss
1306 memmap=nn[KMG]@ss[KMG]
1307 [KNL] Force usage of a specific region of memory
1308 Region of memory to be used, from ss to ss+nn.
1310 memmap=nn[KMG]#ss[KMG]
1311 [KNL,ACPI] Mark specific memory as ACPI data.
1312 Region of memory to be used, from ss to ss+nn.
1314 memmap=nn[KMG]$ss[KMG]
1315 [KNL,ACPI] Mark specific memory as reserved.
1316 Region of memory to be used, from ss to ss+nn.
1317 Example: Exclude memory from 0x18690000-0x1869ffff
1318 memmap=64K$0x18690000
1320 memmap=0x10000$0x18690000
1322 memory_corruption_check=0/1 [X86]
1323 Some BIOSes seem to corrupt the first 64k of
1324 memory when doing things like suspend/resume.
1325 Setting this option will scan the memory
1326 looking for corruption. Enabling this will
1327 both detect corruption and prevent the kernel
1328 from using the memory being corrupted.
1329 However, its intended as a diagnostic tool; if
1330 repeatable BIOS-originated corruption always
1331 affects the same memory, you can use memmap=
1332 to prevent the kernel from using that memory.
1334 memory_corruption_check_size=size [X86]
1335 By default it checks for corruption in the low
1336 64k, making this memory unavailable for normal
1337 use. Use this parameter to scan for
1338 corruption in more or less memory.
1340 memory_corruption_check_period=seconds [X86]
1341 By default it checks for corruption every 60
1342 seconds. Use this parameter to check at some
1343 other rate. 0 disables periodic checking.
1345 memtest= [KNL,X86] Enable memtest
1347 default : 0 <disable>
1348 Specifies the number of memtest passes to be
1349 performed. Each pass selects another test
1350 pattern from a given set of patterns. Memtest
1351 fills the memory with this pattern, validates
1352 memory contents and reserves bad memory
1353 regions that are detected.
1355 meye.*= [HW] Set MotionEye Camera parameters
1356 See Documentation/video4linux/meye.txt.
1358 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1359 Multi-Function General Purpose Timers on AMD Geode
1362 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1363 the BIOS has incorrectly applied a workaround. TinyBIOS
1364 version 0.98 is known to be affected, 0.99 fixes the
1365 problem by letting the user disable the workaround.
1369 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1370 physical address is ignored.
1372 mini2440= [ARM,HW,KNL]
1373 Format:[0..2][b][c][t]
1375 MINI2440 configuration specification:
1376 0 - The attached screen is the 3.5" TFT
1377 1 - The attached screen is the 7" TFT
1378 2 - The VGA Shield is attached (1024x768)
1379 Leaving out the screen size parameter will not load
1380 the TFT driver, and the framebuffer will be left
1382 b - Enable backlight. The TFT backlight pin will be
1383 linked to the kernel VESA blanking code and a GPIO
1384 LED. This parameter is not necessary when using the
1386 c - Enable the s3c camera interface.
1387 t - Reserved for enabling touchscreen support. The
1388 touchscreen support is not enabled in the mainstream
1389 kernel as of 2.6.30, a preliminary port can be found
1390 in the "bleeding edge" mini2440 support kernel at
1391 http://repo.or.cz/w/linux-2.6/mini2440.git
1394 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1395 parameter allows control of the logging verbosity for
1396 the additional memory initialisation checks. A value
1397 of 0 disables mminit logging and a level of 4 will
1398 log everything. Information is printed at KERN_DEBUG
1399 so loglevel=8 may also need to be specified.
1402 [MOUSE] Maximum time between finger touching and
1403 leaving touchpad surface for touch to be considered
1404 a tap and be reported as a left button click (for
1405 touchpads working in absolute mode only).
1407 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1408 reporting absolute coordinates, such as tablets
1409 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1410 reporting absolute coordinates, such as tablets
1412 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1413 is similar to kernelcore except it specifies the
1414 amount of memory used for migratable allocations.
1415 If both kernelcore and movablecore is specified,
1416 then kernelcore will be at *least* the specified
1417 value but may be more. If movablecore on its own
1418 is specified, the administrator must be careful
1419 that the amount of memory usable for all allocations
1425 MTD_Partition= [MTD]
1426 Format: <name>,<region-number>,<size>,<offset>
1428 MTD_Region= [MTD] Format:
1429 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1432 See drivers/mtd/cmdlinepart.c.
1434 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1436 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1438 boundary - index of last SLC block on Flex-OneNAND.
1439 The remaining blocks are configured as MLC blocks.
1440 lock - Configure if Flex-OneNAND boundary should be locked.
1441 Once locked, the boundary cannot be changed.
1442 1 indicates lock status, 0 indicates unlock status.
1445 ARM/S3C2412 JIVE boot control
1447 See arch/arm/mach-s3c2412/mach-jive.c
1449 mtouchusb.raw_coordinates=
1450 [HW] Make the MicroTouch USB driver use raw coordinates
1451 ('y', default) or cooked coordinates ('n')
1453 mtrr_chunk_size=nn[KMG] [X86]
1454 used for mtrr cleanup. It is largest continuous chunk
1455 that could hold holes aka. UC entries.
1457 mtrr_gran_size=nn[KMG] [X86]
1458 Used for mtrr cleanup. It is granularity of mtrr block.
1460 Large value could prevent small alignment from
1463 mtrr_spare_reg_nr=n [X86]
1465 Range: 0,7 : spare reg number
1467 Used for mtrr cleanup. It is spare mtrr entries number.
1468 Set to 2 or more if your graphical card needs more.
1470 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1473 See header of drivers/scsi/NCR_D700.c.
1477 ncr53c400= [HW,SCSI]
1479 ncr53c400a= [HW,SCSI]
1481 ncr53c406a= [HW,SCSI]
1483 ncr53c8xx= [HW,SCSI]
1485 netdev= [NET] Network devices parameters
1486 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1487 Note that mem_start is often overloaded to mean
1488 something different and driver-specific.
1489 This usage is only documented in each driver source
1493 [NETFILTER] Enable connection tracking flow accounting
1494 0 to disable accounting
1495 1 to enable accounting
1496 Default value depends on CONFIG_NF_CT_ACCT that is
1497 going to be removed in 2.6.29.
1500 See Documentation/filesystems/nfsroot.txt.
1502 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1503 See Documentation/filesystems/nfsroot.txt.
1505 nfs.callback_tcpport=
1506 [NFS] set the TCP port on which the NFSv4 callback
1507 channel should listen.
1509 nfs.idmap_cache_timeout=
1510 [NFS] set the maximum lifetime for idmapper cache
1514 [NFS] enable 64-bit inode numbers.
1515 If zero, the NFS client will fake up a 32-bit inode
1516 number for the readdir() and stat() syscalls instead
1517 of returning the full 64-bit number.
1518 The default is to return 64-bit inode numbers.
1520 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1521 when a NMI is triggered.
1522 Format: [state][,regs][,debounce][,die]
1524 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1525 Format: [panic,][num]
1527 0 - turn nmi_watchdog off
1528 1 - use the IO-APIC timer for the NMI watchdog
1529 2 - use the local APIC for the NMI watchdog using
1530 a performance counter. Note: This will use one
1531 performance counter and the local APIC's performance
1533 When panic is specified, panic when an NMI watchdog
1535 This is useful when you use a panic=... timeout and
1536 need the box quickly up again.
1537 Instead of 1 and 2 it is possible to use the following
1538 symbolic names: lapic and ioapic
1539 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1541 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1542 emulation library even if a 387 maths coprocessor
1546 [HW] Never suspend the console
1547 Disable suspending of consoles during suspend and
1548 hibernate operations. Once disabled, debugging
1549 messages can reach various consoles while the rest
1550 of the system is being put to sleep (ie, while
1551 debugging driver suspend/resume hooks). This may
1552 not work reliably with all consoles, but is known
1553 to work with serial and VGA consoles.
1555 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1556 caches in the slab allocator. Saves per-node memory,
1557 but will impact performance.
1561 noapic [SMP,APIC] Tells the kernel to not make use of any
1562 IOAPICs that may be present in the system.
1564 nobats [PPC] Do not use BATs for mapping kernel lowmem
1565 on "Classic" PPC cores.
1569 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1571 nodelayacct [KNL] Disable per-task delay accounting
1573 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1575 nodsp [SH] Disable hardware DSP at boot time.
1577 noefi [X86] Disable EFI runtime services support.
1582 On X86-32 available only on PAE configured kernels.
1583 noexec=on: enable non-executable mappings (default)
1584 noexec=off: disable non-executable mappings
1587 This affects only 32-bit executables.
1588 noexec32=on: enable non-executable mappings (default)
1589 read doesn't imply executable mappings
1590 noexec32=off: disable non-executable mappings
1591 read implies executable mappings
1593 nofpu [SH] Disable hardware FPU at boot time.
1595 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1596 register save and restore. The kernel will only save
1597 legacy floating-point registers on task switch.
1599 noxsave [BUGS=X86] Disables x86 extended register state save
1600 and restore using xsave. The kernel will fallback to
1601 enabling legacy floating-point and sse state.
1603 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1604 wfi(ARM) instruction doesn't work correctly and not to
1605 use it. This is also useful when using JTAG debugger.
1607 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1608 instruction doesn't work correctly and not to
1611 no_file_caps Tells the kernel not to honor file capabilities. The
1612 only way then for a file to be executed with privilege
1613 is to be setuid root or executed by root.
1615 nohalt [IA-64] Tells the kernel not to use the power saving
1616 function PAL_HALT_LIGHT when idle. This increases
1617 power-consumption. On the positive side, it reduces
1618 interrupt wake-up latency, which may improve performance
1619 in certain environments such as networked servers or
1622 nohz= [KNL] Boottime enable/disable dynamic ticks
1623 Valid arguments: on, off
1626 noiotrap [SH] Disables trapped I/O port accesses.
1628 noirqdebug [X86-32] Disables the code which attempts to detect and
1629 disable unhandled interrupt sources.
1631 no_timer_check [X86,APIC] Disables the code which tests for
1632 broken timer IRQ sources.
1634 noisapnp [ISAPNP] Disables ISA PnP code.
1636 noinitrd [RAM] Tells the kernel not to load any configured
1639 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1644 nojitter [IA64] Disables jitter checking for ITC timers.
1646 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1648 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1650 noltlbs [PPC] Do not use large page/tlb entries for kernel
1651 lowmem mapping on PPC40x.
1653 nomca [IA-64] Disable machine check abort handling
1655 nomce [X86-32] Machine Check Exception
1657 nomfgpt [X86-32] Disable Multi-Function General Purpose
1658 Timer usage (for AMD Geode machines).
1660 norandmaps Don't use address space randomization. Equivalent to
1661 echo 0 > /proc/sys/kernel/randomize_va_space
1663 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1665 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1666 with UP alternatives
1668 noresidual [PPC] Don't use residual data on PReP machines.
1670 noresume [SWSUSP] Disables resume and restores original swap
1673 no-scroll [VGA] Disables scrollback.
1674 This is required for the Braillex ib80-piezo Braille
1675 reader made by F.H. Papenmeier (Germany).
1679 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1681 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1682 and disable the IO APIC. legacy for "maxcpus=0".
1684 nosoftlockup [KNL] Disable the soft-lockup detector.
1686 noswapaccount [KNL] Disable accounting of swap in memory resource
1687 controller. (See Documentation/cgroups/memory.txt)
1689 nosync [HW,M68K] Disables sync negotiation for all devices.
1691 notsc [BUGS=X86-32] Disable Time Stamp Counter
1693 nousb [USB] Disable the USB subsystem
1697 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1699 nptcg= [IA64] Override max number of concurrent global TLB
1700 purges which is reported from either PAL_VM_SUMMARY or
1703 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1705 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1706 one of ['zone', 'node', 'default'] can be specified
1707 This can be set from sysctl after boot.
1708 See Documentation/sysctl/vm.txt for details.
1710 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1711 See Documentation/debugging-via-ohci1394.txt for more
1714 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1715 Rather than timing out after 20 ms if an EC
1716 command is not properly ACKed, override the length
1717 of the timeout. We have interrupts disabled while
1718 waiting for the ACK, so if this is set too high
1719 interrupts *may* be lost!
1724 oprofile.timer= [HW]
1725 Use timer interrupt instead of performance counters
1727 oprofile.cpu_type= Force an oprofile cpu type
1728 This might be useful if you have an older oprofile
1729 userland or if you want common events.
1730 Format: { archperfmon }
1731 archperfmon: [X86] Force use of architectural
1732 perfmon on Intel CPUs instead of the
1733 CPU specific event set.
1735 osst= [HW,SCSI] SCSI Tape Driver
1736 Format: <buffer_size>,<write_threshold>
1737 See also Documentation/scsi/st.txt.
1739 panic= [KNL] Kernel behaviour on panic
1742 parkbd.port= [HW] Parallel port number the keyboard adapter is
1743 connected to, default is 0.
1745 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1746 0 for XT, 1 for AT (default is AT).
1749 parport= [HW,PPT] Specify parallel ports. 0 disables.
1750 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1751 Use 'auto' to force the driver to use any
1752 IRQ/DMA settings detected (the default is to
1753 ignore detected IRQ/DMA settings because of
1754 possible conflicts). You can specify the base
1755 address, IRQ, and DMA settings; IRQ and DMA
1756 should be numbers, or 'auto' (for using detected
1757 settings on that particular port), or 'nofifo'
1758 (to avoid using a FIFO even if it is detected).
1759 Parallel ports are assigned in the order they
1760 are specified on the command line, starting
1763 parport_init_mode= [HW,PPT]
1764 Configure VIA parallel port to operate in
1765 a specific mode. This is necessary on Pegasos
1766 computer where firmware has no options for setting
1767 up parallel port mode and sets it to spp.
1768 Currently this function knows 686a and 8231 chips.
1769 Format: [spp|ps2|epp|ecp|ecpepp]
1771 pas2= [HW,OSS] Format:
1772 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1775 See header of drivers/scsi/pas16.c.
1778 Halt all CPUs after the first oops has been printed for
1779 the specified number of seconds. This is to be used if
1780 your oopses keep scrolling off the screen.
1785 See header of drivers/block/paride/pcd.c.
1786 See also Documentation/blockdev/paride.txt.
1788 pci=option[,option...] [PCI] various PCI subsystem options:
1789 earlydump [X86] dump PCI config space before the kernel
1791 off [X86] don't probe for the PCI bus
1792 bios [X86-32] force use of PCI BIOS, don't access
1793 the hardware directly. Use this if your machine
1794 has a non-standard PCI host bridge.
1795 nobios [X86-32] disallow use of PCI BIOS, only direct
1796 hardware access methods are allowed. Use this
1797 if you experience crashes upon bootup and you
1798 suspect they are caused by the BIOS.
1799 conf1 [X86] Force use of PCI Configuration
1801 conf2 [X86] Force use of PCI Configuration
1803 noaer [PCIE] If the PCIEAER kernel config parameter is
1804 enabled, this kernel boot option can be used to
1805 disable the use of PCIE advanced error reporting.
1806 nodomains [PCI] Disable support for multiple PCI
1807 root domains (aka PCI segments, in ACPI-speak).
1808 nommconf [X86] Disable use of MMCONFIG for PCI
1810 check_enable_amd_mmconf [X86] check for and enable
1811 properly configured MMIO access to PCI
1812 config space on AMD family 10h CPU
1813 nomsi [MSI] If the PCI_MSI kernel config parameter is
1814 enabled, this kernel boot option can be used to
1815 disable the use of MSI interrupts system-wide.
1816 noioapicquirk [APIC] Disable all boot interrupt quirks.
1817 Safety option to keep boot IRQs enabled. This
1818 should never be necessary.
1819 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1820 primary IO-APIC for bridges that cannot disable
1821 boot IRQs. This fixes a source of spurious IRQs
1822 when the system masks IRQs.
1823 noioapicreroute [APIC] Disable workaround that uses the
1824 boot IRQ equivalent of an IRQ that connects to
1825 a chipset where boot IRQs cannot be disabled.
1826 The opposite of ioapicreroute.
1827 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1828 routing table. These calls are known to be buggy
1829 on several machines and they hang the machine
1830 when used, but on other computers it's the only
1831 way to get the interrupt routing table. Try
1832 this option if the kernel is unable to allocate
1833 IRQs or discover secondary PCI buses on your
1835 rom [X86] Assign address space to expansion ROMs.
1836 Use with caution as certain devices share
1837 address decoders between ROMs and other
1839 norom [X86] Do not assign address space to
1840 expansion ROMs that do not already have
1841 BIOS assigned address ranges.
1842 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1843 assigned automatically to PCI devices. You can
1844 make the kernel exclude IRQs of your ISA cards
1846 pirqaddr=0xAAAAA [X86] Specify the physical address
1847 of the PIRQ table (normally generated
1848 by the BIOS) if it is outside the
1849 F0000h-100000h range.
1850 lastbus=N [X86] Scan all buses thru bus #N. Can be
1851 useful if the kernel is unable to find your
1852 secondary buses and you want to tell it
1853 explicitly which ones they are.
1854 assign-busses [X86] Always assign all PCI bus
1855 numbers ourselves, overriding
1856 whatever the firmware may have done.
1857 usepirqmask [X86] Honor the possible IRQ mask stored
1858 in the BIOS $PIR table. This is needed on
1859 some systems with broken BIOSes, notably
1860 some HP Pavilion N5400 and Omnibook XE3
1861 notebooks. This will have no effect if ACPI
1862 IRQ routing is enabled.
1863 noacpi [X86] Do not use ACPI for IRQ routing
1864 or for PCI scanning.
1865 nocrs [X86] Don't use _CRS for PCI resource
1867 routeirq Do IRQ routing for all PCI devices.
1868 This is normally done in pci_enable_device(),
1869 so this option is a temporary workaround
1870 for broken drivers that don't call it.
1871 skip_isa_align [X86] do not align io start addr, so can
1872 handle more pci cards
1873 firmware [ARM] Do not re-enumerate the bus but instead
1874 just use the configuration from the
1875 bootloader. This is currently used on
1876 IXP2000 systems where the bus has to be
1877 configured a certain way for adjunct CPUs.
1878 noearly [X86] Don't do any early type 1 scanning.
1879 This might help on some broken boards which
1880 machine check when some devices' config space
1881 is read. But various workarounds are disabled
1882 and some IOMMU drivers will not work.
1883 bfsort Sort PCI devices into breadth-first order.
1884 This sorting is done to get a device
1885 order compatible with older (<= 2.4) kernels.
1886 nobfsort Don't sort PCI devices into breadth-first order.
1887 cbiosize=nn[KMG] The fixed amount of bus space which is
1888 reserved for the CardBus bridge's IO window.
1889 The default value is 256 bytes.
1890 cbmemsize=nn[KMG] The fixed amount of bus space which is
1891 reserved for the CardBus bridge's memory
1892 window. The default value is 64 megabytes.
1895 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
1896 Specifies alignment and device to reassign
1897 aligned memory resources.
1898 If <order of align> is not specified,
1899 PAGE_SIZE is used as alignment.
1900 PCI-PCI bridge can be specified, if resource
1901 windows need to be expanded.
1902 ecrc= Enable/disable PCIe ECRC (transaction layer
1903 end-to-end CRC checking).
1904 bios: Use BIOS/firmware settings. This is the
1909 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1912 force Enable ASPM even on devices that claim not to support it.
1913 WARNING: Forcing ASPM on may cause system lockups.
1915 pcmv= [HW,PCMCIA] BadgePAD 4
1918 See Documentation/blockdev/paride.txt.
1920 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1923 See arch/parisc/kernel/pdc_chassis.c
1926 See Documentation/blockdev/paride.txt.
1929 See Documentation/blockdev/paride.txt.
1931 pirq= [SMP,APIC] Manual mp-table setup
1932 See Documentation/x86/i386/IO-APIC.txt.
1934 plip= [PPT,NET] Parallel port network link
1935 Format: { parport<nr> | timid | 0 }
1936 See also Documentation/parport.txt.
1938 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1939 Override pmtimer IOPort with a hex value.
1943 Enable PNP debug messages. This depends on the
1944 CONFIG_PNP_DEBUG_MESSAGES option.
1950 { on | off | curr | res | no-curr | no-res }
1953 [ISAPNP] Exclude IRQs for the autoconfiguration
1956 [ISAPNP] Exclude DMAs for the autoconfiguration
1958 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1959 Ranges are in pairs (I/O port base and size).
1962 [ISAPNP] Exclude memory regions for the
1964 Ranges are in pairs (memory base and size).
1966 ports= [IP_VS_FTP] IPVS ftp helper module
1968 Up to 8 (IP_VS_APP_MAX_PORTS) ports
1970 Format: <port>,<port>....
1972 print-fatal-signals=
1973 [KNL] debug: print fatal signals
1974 print-fatal-signals=1: print segfault info to
1978 printk.time= Show timing data prefixed to each printk message line
1979 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1981 processor.max_cstate= [HW,ACPI]
1982 Limit processor to maximum C-state
1983 max_cstate=9 overrides any DMI blacklist limit.
1985 processor.nocst [HW,ACPI]
1986 Ignore the _CST method to determine C-states,
1987 instead using the legacy FADT method
1989 profile= [KNL] Enable kernel profiling via /proc/profile
1990 Format: [schedule,]<number>
1991 Param: "schedule" - profile schedule points.
1992 Param: <number> - step/bucket size as a power of 2 for
1993 statistical time based profiling.
1994 Param: "sleep" - profile D-state sleeping (millisecs).
1995 Requires CONFIG_SCHEDSTATS
1996 Param: "kvm" - profile VM exits.
1998 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2000 See Documentation/blockdev/ramdisk.txt.
2002 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2003 probe for; one of (bare|imps|exps|lifebook|any).
2004 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2006 psmouse.resetafter= [HW,MOUSE]
2007 Try to reset the device after so many bad packets
2010 [HW,MOUSE] Set desired mouse resolution, in dpi.
2011 psmouse.smartscroll=
2012 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2013 0 = disabled, 1 = enabled (default).
2015 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
2017 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
2020 See Documentation/blockdev/paride.txt.
2023 [KNL] Number of legacy pty's. Overwrites compiled-in
2026 quiet [KNL] Disable most log messages
2031 See Documentation/md.txt.
2033 ramdisk_blocksize= [RAM]
2034 See Documentation/blockdev/ramdisk.txt.
2036 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2037 See Documentation/blockdev/ramdisk.txt.
2039 rcupdate.blimit= [KNL,BOOT]
2040 Set maximum number of finished RCU callbacks to process
2043 rcupdate.qhimark= [KNL,BOOT]
2044 Set threshold of queued
2045 RCU callbacks over which batch limiting is disabled.
2047 rcupdate.qlowmark= [KNL,BOOT]
2048 Set threshold of queued RCU callbacks below which
2049 batch limiting is re-enabled.
2053 Run specified binary instead of /init from the ramdisk,
2054 used for early userspace startup. See initrd.
2056 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2057 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2058 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2061 [KNL, SMP] Set scheduler's default relax_domain_level.
2062 See Documentation/cgroups/cpusets.txt.
2064 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2066 reservetop= [X86-32]
2068 Reserves a hole at the top of the kernel virtual
2071 reset_devices [KNL] Force drivers to reset the underlying device
2072 during initialization.
2075 Specify the partition device for software suspend
2077 resume_offset= [SWSUSP]
2078 Specify the offset from the beginning of the partition
2079 given by "resume=" at which the swap header is located,
2080 in <PAGE_SIZE> units (needed only for swap files).
2081 See Documentation/power/swsusp-and-swap-files.txt
2083 retain_initrd [RAM] Keep initrd memory after extraction
2085 rhash_entries= [KNL,NET]
2086 Set number of hash buckets for route cache
2088 riscom8= [HW,SERIAL]
2089 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2091 ro [KNL] Mount root device read-only on boot
2093 root= [KNL] Root filesystem
2095 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2096 mount the root filesystem
2098 rootflags= [KNL] Set root filesystem mount option string
2100 rootfstype= [KNL] Set root filesystem type
2102 rootwait [KNL] Wait (indefinitely) for root device to show up.
2103 Useful for devices that are detected asynchronously
2104 (e.g. USB and MMC devices).
2106 root_plug.vendor_id=
2107 [ROOTPLUG] Override the default vendor ID
2109 root_plug.product_id=
2110 [ROOTPLUG] Override the default product ID
2113 [ROOTPLUG] Enable debugging output
2115 rw [KNL] Mount root device read-write on boot
2117 S [KNL] Run init in single mode
2120 See drivers/net/irda/sa1100_ir.c.
2122 sbni= [NET] Granch SBNI12 leased line adapter
2124 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
2125 Format: <io>[,<timeout>[,<isapnp>]]
2127 scsi_debug_*= [SCSI]
2128 See drivers/scsi/scsi_debug.c.
2130 scsi_default_dev_flags=
2131 [SCSI] SCSI default device flags
2134 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2135 Format: <vendor>:<model>:<flags>
2136 (flags are integer value)
2138 scsi_logging_level= [SCSI] a bit mask of logging levels
2139 See drivers/scsi/scsi_logging.h for bits. Also
2140 settable via sysctl at dev.scsi.logging_level
2141 (/proc/sys/dev/scsi/logging_level).
2142 There is also a nice 'scsi_logging_level' script in the
2143 S390-tools package, available for download at
2144 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2146 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2147 discovered. async scans them in kernel threads,
2148 allowing boot to proceed. none ignores them, expecting
2149 user space to do the scan.
2151 security= [SECURITY] Choose a security module to enable at boot.
2152 If this boot parameter is not specified, only the first
2153 security module asking for security registration will be
2154 loaded. An invalid security module name will be treated
2155 as if no module has been chosen.
2157 selinux= [SELINUX] Disable or enable SELinux at boot time.
2158 Format: { "0" | "1" }
2159 See security/selinux/Kconfig help text.
2162 Default value is set via kernel config option.
2163 If enabled at boot time, /selinux/disable can be used
2164 later to disable prior to initial policy load.
2166 serialnumber [BUGS=X86-32]
2169 Maximal number of shapers.
2171 show_msr= [x86] show boot-time MSR settings
2172 Format: { <integer> }
2173 Show boot-time (BIOS-initialized) MSR settings.
2174 The parameter means the number of CPUs to show,
2175 for example 1 means boot CPU only.
2178 See header of drivers/scsi/sim710.c.
2185 slub_debug[=options[,slabs]] [MM, SLUB]
2186 Enabling slub_debug allows one to determine the
2187 culprit if slab objects become corrupted. Enabling
2188 slub_debug can create guard zones around objects and
2189 may poison objects when not in use. Also tracks the
2190 last alloc / free. For more information see
2191 Documentation/vm/slub.txt.
2193 slub_max_order= [MM, SLUB]
2194 Determines the maximum allowed order for slabs.
2195 A high setting may cause OOMs due to memory
2196 fragmentation. For more information see
2197 Documentation/vm/slub.txt.
2199 slub_min_objects= [MM, SLUB]
2200 The minimum number of objects per slab. SLUB will
2201 increase the slab order up to slub_max_order to
2202 generate a sufficiently large slab able to contain
2203 the number of objects indicated. The higher the number
2204 of objects the smaller the overhead of tracking slabs
2205 and the less frequently locks need to be acquired.
2206 For more information see Documentation/vm/slub.txt.
2208 slub_min_order= [MM, SLUB]
2209 Determines the mininum page order for slabs. Must be
2210 lower than slub_max_order.
2211 For more information see Documentation/vm/slub.txt.
2213 slub_nomerge [MM, SLUB]
2214 Disable merging of slabs with similar size. May be
2215 necessary if there is some reason to distinguish
2216 allocs to different slabs. Debug options disable
2217 merging on their own.
2218 For more information see Documentation/vm/slub.txt.
2221 Format: <io1>[,<io2>[,...,<io8>]]
2223 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2224 attempt to substitute SMP alternatives once at boot.
2226 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2227 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2228 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2229 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2230 smsc-ircc2.ircc_irq= [HW] IRQ line
2231 smsc-ircc2.ircc_dma= [HW] DMA channel
2232 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2233 0: Toshiba Satellite 1800 (GP data pin select)
2234 1: Fast pin select (default)
2237 snd-ad1816a= [HW,ALSA]
2239 snd-ad1848= [HW,ALSA]
2241 snd-ali5451= [HW,ALSA]
2243 snd-als100= [HW,ALSA]
2245 snd-als4000= [HW,ALSA]
2247 snd-azt2320= [HW,ALSA]
2249 snd-cmi8330= [HW,ALSA]
2251 snd-cmipci= [HW,ALSA]
2253 snd-cs4231= [HW,ALSA]
2255 snd-cs4232= [HW,ALSA]
2257 snd-cs4236= [HW,ALSA]
2259 snd-cs4281= [HW,ALSA]
2261 snd-cs46xx= [HW,ALSA]
2263 snd-dt019x= [HW,ALSA]
2265 snd-dummy= [HW,ALSA]
2267 snd-emu10k1= [HW,ALSA]
2269 snd-ens1370= [HW,ALSA]
2271 snd-ens1371= [HW,ALSA]
2273 snd-es968= [HW,ALSA]
2275 snd-es1688= [HW,ALSA]
2277 snd-es18xx= [HW,ALSA]
2279 snd-es1938= [HW,ALSA]
2281 snd-es1968= [HW,ALSA]
2283 snd-fm801= [HW,ALSA]
2285 snd-gusclassic= [HW,ALSA]
2287 snd-gusextreme= [HW,ALSA]
2289 snd-gusmax= [HW,ALSA]
2293 snd-ice1712= [HW,ALSA]
2295 snd-intel8x0= [HW,ALSA]
2297 snd-interwave= [HW,ALSA]
2302 snd-korg1212= [HW,ALSA]
2304 snd-maestro3= [HW,ALSA]
2306 snd-mpu401= [HW,ALSA]
2308 snd-mtpav= [HW,ALSA]
2310 snd-nm256= [HW,ALSA]
2312 snd-opl3sa2= [HW,ALSA]
2320 snd-opti93x= [HW,ALSA]
2324 snd-rme32= [HW,ALSA]
2326 snd-rme96= [HW,ALSA]
2328 snd-rme9652= [HW,ALSA]
2334 snd-sbawe= [HW,ALSA]
2336 snd-serial= [HW,ALSA]
2338 snd-sgalaxy= [HW,ALSA]
2340 snd-sonicvibes= [HW,ALSA]
2345 snd-sun-cs4231= [HW,ALSA]
2347 snd-trident= [HW,ALSA]
2349 snd-usb-audio= [HW,ALSA,USB]
2351 snd-via82xx= [HW,ALSA]
2353 snd-virmidi= [HW,ALSA]
2355 snd-wavefront= [HW,ALSA]
2357 snd-ymfpci= [HW,ALSA]
2360 [KNL] Should the soft-lockup detector generate panics.
2362 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2363 See Documentation/sonypi.txt
2365 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2366 See Documentation/serial/specialix.txt.
2368 spia_io_base= [HW,MTD]
2374 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2376 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2377 See Documentation/scsi/st.txt.
2380 Enabled the stack tracer on boot up.
2384 Set the STI (builtin display/keyboard on the HP-PARISC
2385 machines) console (graphic card) which should be used
2386 as the initial boot-console.
2387 See also comment in drivers/video/console/sticore.c.
2390 See comment in drivers/video/console/sticore.c.
2393 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2397 Control how the NFS server code allocates CPUs to
2398 service thread pools. Depending on how many NICs
2399 you have and where their interrupts are bound, this
2400 option will affect which CPUs will do NFS serving.
2401 Note: this parameter cannot be changed while the
2402 NFS server is running.
2404 auto the server chooses an appropriate mode
2405 automatically using heuristics
2406 global a single global pool contains all CPUs
2407 percpu one pool for each CPU
2408 pernode one pool for each NUMA node (equivalent
2409 to global on non-NUMA machines)
2411 swiotlb= [IA-64] Number of I/O TLB slabs
2415 sym53c416= [HW,SCSI]
2416 See header of drivers/scsi/sym53c416.c.
2418 sysrq_always_enabled
2420 Ignore sysrq setting - this boot parameter will
2421 neutralize any effect of /proc/sys/kernel/sysrq.
2422 Useful for debugging.
2425 See header of drivers/scsi/t128.c.
2429 test_suspend= [SUSPEND]
2430 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2431 standby suspend) as the system sleep state to briefly
2432 enter during system startup. The system is woken from
2433 this state using a wakeup-capable RTC alarm.
2435 thash_entries= [KNL,NET]
2436 Set number of hash buckets for TCP connection
2438 thermal.act= [HW,ACPI]
2439 -1: disable all active trip points in all thermal zones
2440 <degrees C>: override all lowest active trip points
2442 thermal.crt= [HW,ACPI]
2443 -1: disable all critical trip points in all thermal zones
2444 <degrees C>: override all critical trip points
2446 thermal.nocrt= [HW,ACPI]
2447 Set to disable actions on ACPI thermal zone
2448 critical and hot trip points.
2450 thermal.off= [HW,ACPI]
2451 1: disable ACPI thermal control
2453 thermal.psv= [HW,ACPI]
2454 -1: disable all passive trip points
2455 <degrees C>: override all passive trip points to this
2458 thermal.tzp= [HW,ACPI]
2459 Specify global default ACPI thermal zone polling rate
2460 <deci-seconds>: poll all this frequency
2461 0: no polling (default)
2464 See comment before function dc390_setup() in
2465 drivers/scsi/tmscsim.c.
2469 Specify if the kernel should make use of the cpu
2470 topology informations if the hardware supports these.
2471 The scheduler will make use of these informations and
2472 e.g. base its process migration decisions on it.
2477 trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
2479 trix= [HW,OSS] MediaTrix AudioTrix Pro
2481 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2483 tsc= Disable clocksource-must-verify flag for TSC.
2485 [x86] reliable: mark tsc clocksource as reliable, this
2486 disables clocksource verification at runtime.
2487 Used to enable high-resolution timer mode on older
2488 hardware, and in virtualized environment.
2490 turbografx.map[2|3]= [HW,JOY]
2491 TurboGraFX parallel port interface
2493 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2494 See also Documentation/input/joystick-parport.txt
2496 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2497 See header of drivers/scsi/u14-34f.c.
2506 [USB] Ignore overcurrent events (default N).
2507 Some badly-designed motherboards generate lots of
2508 bogus events, for ports that aren't wired to
2509 anything. Set this parameter to avoid log spamming.
2510 Note that genuine overcurrent events won't be
2515 Set unknown_nmi_panic=1 early on boot.
2517 usbcore.autosuspend=
2518 [USB] The autosuspend time delay (in seconds) used
2519 for newly-detected USB devices (default 2). This
2520 is the time required before an idle device will be
2521 autosuspended. Devices for which the delay is set
2522 to a negative value won't be autosuspended at all.
2524 usbcore.usbfs_snoop=
2525 [USB] Set to log all usbfs traffic (default 0 = off).
2527 usbcore.blinkenlights=
2528 [USB] Set to cycle leds on hubs (default 0 = off).
2530 usbcore.old_scheme_first=
2531 [USB] Start with the old device initialization
2532 scheme (default 0 = off).
2534 usbcore.use_both_schemes=
2535 [USB] Try the other device initialization scheme
2536 if the first one fails (default 1 = enabled).
2538 usbcore.initial_descriptor_timeout=
2539 [USB] Specifies timeout for the initial 64-byte
2540 USB_REQ_GET_DESCRIPTOR request in milliseconds
2541 (default 5000 = 5.0 seconds).
2544 [USBHID] The interval which mice are to be polled at.
2546 usb-storage.delay_use=
2547 [UMS] The delay in seconds before a new device is
2548 scanned for Logical Units (default 5).
2551 [UMS] A list of quirks entries to supplement or
2552 override the built-in unusual_devs list. List
2553 entries are separated by commas. Each entry has
2554 the form VID:PID:Flags where VID and PID are Vendor
2555 and Product ID values (4-digit hex numbers) and
2556 Flags is a set of characters, each corresponding
2557 to a common usb-storage quirk flag as follows:
2558 a = SANE_SENSE (collect more than 18 bytes
2560 c = FIX_CAPACITY (decrease the reported
2561 device capacity by one sector);
2562 h = CAPACITY_HEURISTICS (decrease the
2563 reported device capacity by one
2564 sector if the number is odd);
2565 i = IGNORE_DEVICE (don't bind to this
2567 l = NOT_LOCKABLE (don't try to lock and
2568 unlock ejectable media);
2569 m = MAX_SECTORS_64 (don't transfer more
2570 than 64 sectors = 32 KB at a time);
2571 o = CAPACITY_OK (accept the capacity
2572 reported by the device);
2573 r = IGNORE_RESIDUE (the device reports
2574 bogus residue values);
2575 s = SINGLE_LUN (the device has only one
2577 w = NO_WP_DETECT (don't test whether the
2578 medium is write-protected).
2579 Example: quirks=0419:aaf5:rl,0421:0433:rc
2582 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2583 vdso=1: enable VDSO (default)
2584 vdso=0: disable VDSO mapping
2587 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2588 vdso32=1: enable 32-bit VDSO (default)
2589 vdso32=0: disable 32-bit VDSO mapping
2592 vector=percpu: enable percpu vector domain
2594 video= [FB] Frame buffer configuration
2595 See Documentation/fb/modedb.txt.
2597 vga= [BOOT,X86-32] Select a particular video mode
2598 See Documentation/x86/boot.txt and
2599 Documentation/svga.txt.
2600 Use vga=ask for menu.
2601 This is actually a boot loader parameter; the value is
2602 passed to the kernel using a special protocol.
2604 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2605 size of <nn>. This can be used to increase the
2606 minimum size (128MB on x86). It can also be used to
2607 decrease the size and leave more room for directly
2610 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2613 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2616 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2619 vt.default_blu= [VT]
2620 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2621 Change the default blue palette of the console.
2622 This is a 16-member array composed of values
2625 vt.default_grn= [VT]
2626 Format: <green0>,<green1>,<green2>,...,<green15>
2627 Change the default green palette of the console.
2628 This is a 16-member array composed of values
2631 vt.default_red= [VT]
2632 Format: <red0>,<red1>,<red2>,...,<red15>
2633 Change the default red palette of the console.
2634 This is a 16-member array composed of values
2640 Set system-wide default UTF-8 mode for all tty's.
2641 Default is 1, i.e. UTF-8 mode is enabled for all
2642 newly opened terminals.
2644 waveartist= [HW,OSS]
2645 Format: <io>,<irq>,<dma>,<dma2>
2648 See header of drivers/scsi/wd33c93.c.
2651 See header of drivers/scsi/wd7000.c.
2654 See Documentation/watchdog/wdt.txt.
2656 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2657 default x2apic cluster mode on platforms
2660 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2661 xd_geo= See header of drivers/block/xd.c.
2663 xirc2ps_cs= [NET,PCMCIA]
2665 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2667 ______________________________________________________________________
2671 Add documentation for ALSA options.
2672 Add more DRM drivers.
git.openpandora.org / pandora-kernel.git / blob