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 ARM ARM architecture is enabled.
44 AVR32 AVR32 architecture is enabled.
45 AX25 Appropriate AX.25 support is enabled.
46 BLACKFIN Blackfin architecture is enabled.
47 DRM Direct Rendering Management support is enabled.
48 DYNAMIC_DEBUG Build in debug messages and enable them at runtime
49 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
50 EFI EFI Partitioning (GPT) is enabled
51 EIDE EIDE/ATAPI support is enabled.
52 FB The frame buffer device is enabled.
53 FTRACE Function tracing enabled.
54 GCOV GCOV profiling is enabled.
55 HW Appropriate hardware is enabled.
56 IA-64 IA-64 architecture is enabled.
57 IMA Integrity measurement architecture is enabled.
58 IOSCHED More than one I/O scheduler is enabled.
59 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
60 IPV6 IPv6 support is enabled.
61 ISAPNP ISA PnP code is enabled.
62 ISDN Appropriate ISDN support is enabled.
63 JOY Appropriate joystick support is enabled.
64 KGDB Kernel debugger support is enabled.
65 KVM Kernel Virtual Machine support is enabled.
66 LIBATA Libata driver is enabled
67 LP Printer support is enabled.
68 LOOP Loopback device support is enabled.
69 M68k M68k architecture is enabled.
70 These options have more detailed description inside of
71 Documentation/m68k/kernel-options.txt.
72 MCA MCA bus support is enabled.
73 MDA MDA console support is enabled.
74 MIPS MIPS architecture is enabled.
75 MOUSE Appropriate mouse support is enabled.
76 MSI Message Signaled Interrupts (PCI).
77 MTD MTD (Memory Technology Device) support is enabled.
78 NET Appropriate network support is enabled.
79 NUMA NUMA support is enabled.
80 NFS Appropriate NFS support is enabled.
81 OSS OSS sound support is enabled.
82 PV_OPS A paravirtualized kernel is enabled.
83 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
84 PARISC The PA-RISC architecture is enabled.
85 PCI PCI bus support is enabled.
86 PCIE PCI Express support is enabled.
87 PCMCIA The PCMCIA subsystem is enabled.
88 PNP Plug & Play support is enabled.
89 PPC PowerPC architecture is enabled.
90 PPT Parallel port support is enabled.
91 PS2 Appropriate PS/2 support is enabled.
92 RAM RAM disk support is enabled.
93 S390 S390 architecture is enabled.
94 SCSI Appropriate SCSI support is enabled.
95 A lot of drivers have their options described inside
96 the Documentation/scsi/ sub-directory.
97 SECURITY Different security models are enabled.
98 SELINUX SELinux support is enabled.
99 APPARMOR AppArmor support is enabled.
100 SERIAL Serial support is enabled.
101 SH SuperH architecture is enabled.
102 SMP The kernel is an SMP kernel.
103 SPARC Sparc architecture is enabled.
104 SWSUSP Software suspend (hibernation) is enabled.
105 SUSPEND System suspend states are enabled.
106 TPM TPM drivers are enabled.
107 TS Appropriate touchscreen support is enabled.
108 UMS USB Mass Storage support is enabled.
109 USB USB support is enabled.
110 USBHID USB Human Interface Device support is enabled.
111 V4L Video For Linux support is enabled.
112 VGA The VGA console has been enabled.
113 VT Virtual terminal support is enabled.
114 WDT Watchdog support is enabled.
115 XT IBM PC/XT MFM hard disk support is enabled.
116 X86-32 X86-32, aka i386 architecture is enabled.
117 X86-64 X86-64 architecture is enabled.
118 More X86-64 boot options can be found in
119 Documentation/x86/x86_64/boot-options.txt .
120 X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
121 XEN Xen support is enabled
123 In addition, the following text indicates that the option:
125 BUGS= Relates to possible processor bugs on the said processor.
126 KNL Is a kernel start-up parameter.
127 BOOT Is a boot loader parameter.
129 Parameters denoted with BOOT are actually interpreted by the boot
130 loader, and have no meaning to the kernel directly.
131 Do not modify the syntax of boot loader parameters without extreme
132 need or coordination with <Documentation/x86/boot.txt>.
134 There are also arch-specific kernel-parameters not documented here.
135 See for example <Documentation/x86/x86_64/boot-options.txt>.
137 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
138 a trailing = on the name of any parameter states that that parameter will
139 be entered as an environment variable, whereas its absence indicates that
140 it will appear as a kernel argument readable via /proc/cmdline by programs
141 running once the system is up.
143 The number of kernel parameters is not limited, but the length of the
144 complete command line (parameters including spaces etc.) is limited to
145 a fixed number of characters. This limit depends on the architecture
146 and is between 256 and 4096 characters. It is defined in the file
147 ./include/asm/setup.h as COMMAND_LINE_SIZE.
149 Finally, the [KMG] suffix is commonly described after a number of kernel
150 parameter values. These 'K', 'M', and 'G' letters represent the _binary_
151 multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
152 bytes respectively. Such letter suffixes can also be entirely omitted.
156 Advanced Configuration and Power Interface
157 Format: { force | off | strict | noirq | rsdt }
158 force -- enable ACPI if default was off
159 off -- disable ACPI if default was on
160 noirq -- do not use ACPI for IRQ routing
161 strict -- Be less tolerant of platforms that are not
162 strictly ACPI specification compliant.
163 rsdt -- prefer RSDT over (default) XSDT
164 copy_dsdt -- copy DSDT to memory
166 See also Documentation/power/pm.txt, pci=noacpi
168 acpi_rsdp= [ACPI,EFI,KEXEC]
169 Pass the RSDP address to the kernel, mostly used
170 on machines running EFI runtime service to boot the
171 second kernel for kdump.
173 acpi_apic_instance= [ACPI, IOAPIC]
175 2: use 2nd APIC table, if available
176 1,0: use 1st APIC table
179 acpi_backlight= [HW,ACPI]
180 acpi_backlight=vendor
182 If set to vendor, prefer vendor specific driver
183 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
184 of the ACPI video.ko driver.
186 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
187 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
189 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
190 debug output. Bits in debug_layer correspond to a
191 _COMPONENT in an ACPI source file, e.g.,
192 #define _COMPONENT ACPI_PCI_COMPONENT
193 Bits in debug_level correspond to a level in
194 ACPI_DEBUG_PRINT statements, e.g.,
195 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
196 The debug_level mask defaults to "info". See
197 Documentation/acpi/debug.txt for more information about
198 debug layers and levels.
200 Enable processor driver info messages:
201 acpi.debug_layer=0x20000000
202 Enable PCI/PCI interrupt routing info messages:
203 acpi.debug_layer=0x400000
204 Enable AML "Debug" output, i.e., stores to the Debug
205 object while interpreting AML:
206 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
207 Enable all messages related to ACPI hardware:
208 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
210 Some values produce so much output that the system is
211 unusable. The "log_buf_len" parameter may be useful
212 if you need to capture more output.
214 acpi_irq_balance [HW,ACPI]
215 ACPI will balance active IRQs
218 acpi_irq_nobalance [HW,ACPI]
219 ACPI will not move active IRQs (default)
222 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
223 Format: <irq>,<irq>...
225 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
227 Format: <irq>,<irq>...
229 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
231 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
232 Format: To spoof as Windows 98: ="Microsoft Windows"
234 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
235 acpi_osi="string1" # add string1 -- only one string
236 acpi_osi="!string2" # remove built-in string2
237 acpi_osi= # disable all strings
240 Override the pmtimer bug detection: force the kernel
241 to assume that this machine's pmtimer latches its value
242 and always returns good values.
244 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
245 Format: { level | edge | high | low }
247 acpi_serialize [HW,ACPI] force serialization of AML methods
249 acpi_skip_timer_override [HW,ACPI]
250 Recognize and ignore IRQ0/pin2 Interrupt Override.
251 For broken nForce2 BIOS resulting in XT-PIC timer.
253 acpi_sleep= [HW,ACPI] Sleep options
254 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
255 old_ordering, nonvs, sci_force_enable }
256 See Documentation/power/video.txt for information on
258 s3_beep is for debugging; it makes the PC's speaker beep
259 as soon as the kernel's real-mode entry point is called.
260 s4_nohwsig prevents ACPI hardware signature from being
261 used during resume from hibernation.
262 old_ordering causes the ACPI 1.0 ordering of the _PTS
263 control method, with respect to putting devices into
264 low power states, to be enforced (the ACPI 2.0 ordering
265 of _PTS is used by default).
266 nonvs prevents the kernel from saving/restoring the
267 ACPI NVS memory during suspend/hibernation and resume.
268 sci_force_enable causes the kernel to set SCI_EN directly
269 on resume from S1/S3 (which is against the ACPI spec,
270 but some broken systems don't work without it).
272 acpi_use_timer_override [HW,ACPI]
273 Use timer override. For some broken Nvidia NF5 boards
274 that require a timer override, but don't have HPET
276 acpi_enforce_resources= [ACPI]
277 { strict | lax | no }
278 Check for resource conflicts between native drivers
279 and ACPI OperationRegions (SystemIO and SystemMemory
280 only). IO ports and memory declared in ACPI might be
281 used by the ACPI subsystem in arbitrary AML code and
282 can interfere with legacy drivers.
283 strict (default): access to resources claimed by ACPI
284 is denied; legacy drivers trying to access reserved
285 resources will fail to bind to device using them.
286 lax: access to resources claimed by ACPI is allowed;
287 legacy drivers trying to access reserved resources
288 will bind successfully but a warning message is logged.
289 no: ACPI OperationRegions are not marked as reserved,
290 no further checks are performed.
292 add_efi_memmap [EFI; X86] Include EFI memory map in
293 kernel's map of available physical RAM.
296 { off | try_unsupported }
297 off: disable AGP support
298 try_unsupported: try to drive unsupported chipsets
299 (may crash computer or cause data corruption)
302 See Documentation/sound/alsa/alsa-parameters.txt
305 Allow the default userspace alignment fault handler
306 behaviour to be specified. Bit 0 enables warnings,
307 bit 1 enables fixups, and bit 2 sends a segfault.
309 amd_iommu= [HW,X86-84]
310 Pass parameters to the AMD IOMMU driver in the system.
312 fullflush - enable flushing of IO/TLB entries when
313 they are unmapped. Otherwise they are
314 flushed before they will be reused, which
316 off - do not initialize any AMD IOMMU found in
319 amijoy.map= [HW,JOY] Amiga joystick support
320 Map of devices attached to JOY0DAT and JOY1DAT
322 See also Documentation/kernel/input/joystick.txt
324 analog.map= [HW,JOY] Analog joystick and gamepad support
325 Specifies type or capabilities of an analog joystick
326 connected to one of 16 gameports
327 Format: <type1>,<type2>,..<type16>
330 Power management functions (SPARCstation-4/5 + deriv.)
332 Disable APC CPU standby support. SPARCstation-Fox does
333 not play well with APC CPU idle - disable it if you have
334 APC and your system crashes randomly.
336 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
337 Change the output verbosity whilst booting
338 Format: { quiet (default) | verbose | debug }
339 Change the amount of debugging information output
340 when initialising the APIC and IO-APIC components.
343 See Documentation/networking/ipv6.txt.
345 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
346 Limit apic dumping. The parameter defines the maximal
347 number of local apics being dumped. Also it is possible
348 to set it to "all" by meaning -- no limit here.
349 Format: { 1 (default) | 2 | ... | all }.
350 The parameter valid if only apic=debug or
351 apic=verbose is specified.
352 Example: apic=debug show_lapic=all
354 apm= [APM] Advanced Power Management
355 See header of arch/x86/kernel/apm_32.c.
357 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
358 Format: <io>,<irq>,<nodeID>
362 atarimouse= [HW,MOUSE] Atari Mouse
364 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
365 EzKey and similar keyboards
367 atkbd.reset= [HW] Reset keyboard during initialization
369 atkbd.set= [HW] Select keyboard code set
370 Format: <int> (2 = AT (default), 3 = PS/2)
372 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
375 atkbd.softraw= [HW] Choose between synthetic and real raw mode
376 Format: <bool> (0 = real, 1 = synthetic (default))
378 atkbd.softrepeat= [HW]
379 Use software keyboard repeat
383 baycom_epp= [HW,AX25]
386 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
388 See header of drivers/net/hamradio/baycom_par.c.
390 baycom_ser_fdx= [HW,AX25]
391 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
392 Format: <io>,<irq>,<mode>[,<baud>]
393 See header of drivers/net/hamradio/baycom_ser_fdx.c.
395 baycom_ser_hdx= [HW,AX25]
396 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
397 Format: <io>,<irq>,<mode>
398 See header of drivers/net/hamradio/baycom_ser_hdx.c.
400 boot_delay= Milliseconds to delay each printk during boot.
401 Values larger than 10 seconds (10000) are changed to
405 bootmem_debug [KNL] Enable bootmem allocator debug messages.
407 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
408 bttv.radio= Most important insmod options are available as
410 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
411 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
413 bulk_remove=off [PPC] This parameter disables the use of the pSeries
414 firmware feature for flushing multiple hpte entries
417 c101= [NET] Moxa C101 synchronous serial card
419 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
420 Sometimes CPU hardware bugs make them report the cache
421 size incorrectly. The kernel will attempt work arounds
422 to fix known problems, but for some CPUs it is not
423 possible to determine what the correct size should be.
424 This option provides an override for these situations.
427 [SECURITY] Disable capabilities. This would normally
428 be used only if an alternative security model is to be
429 configured. Potentially dangerous and should only be
430 used if you are entirely sure of the consequences.
432 ccw_timeout_log [S390]
433 See Documentation/s390/CommonIO for details.
435 cgroup_disable= [KNL] Disable a particular controller
436 Format: {name of the controller(s) to disable}
437 {Currently supported controllers - "memory"}
439 checkreqprot [SELINUX] Set initial checkreqprot flag value.
440 Format: { "0" | "1" }
441 See security/selinux/Kconfig help text.
442 0 -- check protection applied by kernel (includes
443 any implied execute protection).
444 1 -- check protection requested by application.
445 Default value is set via a kernel config option.
446 Value can be changed at runtime via
447 /selinux/checkreqprot.
450 See Documentation/s390/CommonIO for details.
452 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
454 Forces specified clocksource (if available) to be used
455 when calculating gettimeofday(). If specified
456 clocksource is not available, it defaults to PIT.
457 Format: { pit | tsc | cyclone | pmtmr }
459 clocksource= Override the default clocksource
461 Override the default clocksource and use the clocksource
462 with the name specified.
463 Some clocksource names to choose from, depending on
465 [all] jiffies (this is the base, fallback clocksource)
467 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
468 pxa_timer,timer3,32k_counter,timer0_1
470 [X86-32] pit,hpet,tsc;
471 scx200_hrt on Geode; cyclone on IBM x440
479 clearcpuid=BITNUM [X86]
480 Disable CPUID feature X for the kernel. See
481 arch/x86/include/asm/cpufeature.h for the valid bit
482 numbers. Note the Linux specific bits are not necessarily
483 stable over kernel options, but the vendor specific
485 Also note that user programs calling CPUID directly
486 or using the feature without checking anything
487 will still see it. This just prevents it from
488 being used by the kernel or shown in /proc/cpuinfo.
489 Also note the kernel might malfunction if you disable
492 cmo_free_hint= [PPC] Format: { yes | no }
493 Specify whether pages are marked as being inactive
494 when they are freed. This is used in CMO environments
495 to determine OS memory pressure for page stealing by
499 code_bytes [X86] How many bytes of object code to print
504 hpet64 [X86-64,HPET] enable 64-bit mode of the HPET timer (bnc#456700)
506 com20020= [HW,NET] ARCnet - COM20020 chipset
508 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
510 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
514 ARCnet - COM90xx chipset (memory-mapped buffers)
515 Format: <io>[,<irq>[,<memstart>]]
517 condev= [HW,S390] console device
520 console= [KNL] Output console device and options.
522 tty<n> Use the virtual console device <n>.
526 Use the specified serial port. The options are of
527 the form "bbbbpnf", where "bbbb" is the baud rate,
528 "p" is parity ("n", "o", or "e"), "n" is number of
529 bits, and "f" is flow control ("r" for RTS or
530 omit it). Default is "9600n8".
532 See Documentation/serial-console.txt for more
534 Documentation/networking/netconsole.txt for an
537 uart[8250],io,<addr>[,options]
538 uart[8250],mmio,<addr>[,options]
539 Start an early, polled-mode console on the 8250/16550
540 UART at the specified I/O port or MMIO address,
541 switching to the matching ttyS device later. The
542 options are the same as for ttyS, above.
544 If the device connected to the port is not a TTY but a braille
545 device, prepend "brl," before the device type, for instance
547 For now, only VisioBraille is supported.
549 consoleblank= [KNL] The console blank (screen saver) timeout in
550 seconds. Defaults to 10*60 = 10mins. A value of 0
551 disables the blank timer.
554 [KNL] Change the default value for
555 /proc/<pid>/coredump_filter.
556 See also Documentation/filesystems/proc.txt.
558 cpuidle.off=1 [CPU_IDLE]
559 disable the cpuidle sub-system
561 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
563 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
565 crashkernel=size[KMG][@offset[KMG]]
566 [KNL] Using kexec, Linux can switch to a 'crash kernel'
567 upon panic. This parameter reserves the physical
568 memory region [offset, offset + size] for that kernel
569 image. If '@offset' is omitted, then a suitable offset
570 is selected automatically. Check
571 Documentation/kdump/kdump.txt for further details.
573 crashkernel=range1:size1[,range2:size2,...][@offset]
574 [KNL] Same as above, but depends on the memory
575 in the running system. The syntax of range is
576 start-[end] where start and end are both
577 a memory unit (amount[KMG]). See also
578 Documentation/kdump/kdump.txt for an example.
583 cs89x0_media= [HW,NET]
584 Format: { rj45 | aui | bnc }
587 See header of drivers/s390/block/dasd_devmap.c.
589 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
590 (one device per port)
591 Format: <port#>,<type>
592 See also Documentation/input/joystick-parport.txt
594 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
595 time. See Documentation/dynamic-debug-howto.txt for
598 debug [KNL] Enable kernel debugging (events log level).
601 [KNL] verbose self-tests
603 Print debugging info while doing the locking API
605 We default to 0 (no extra messages), setting it to
606 1 will print _a lot_ more information - normally
607 only useful to kernel developers.
609 debug_objects [KNL] Enable object debugging
612 [KNL] Disable object debugging
614 debugpat [X86] Enable PAT debugging
616 decnet.addr= [HW,NET]
617 Format: <area>[,<node>]
618 See also Documentation/networking/decnet.txt.
621 [same as hugepagesz=] The size of the default
622 HugeTLB page size. This is the size represented by
623 the legacy /proc/ hugepages APIs, used for SHM, and
624 default size when mounting hugetlbfs filesystems.
625 Defaults to the default architecture's huge page size
629 Set number of hash buckets for dentry cache.
632 IO parameters + enable/disable command.
634 digiepca= [HW,SERIAL]
635 See drivers/char/README.epca and
636 Documentation/serial/digiepca.txt.
639 See Documentation/networking/ipv6.txt.
641 disable_ddw [PPC/PSERIES]
642 Disable Dynamic DMA Window support. Use this if
643 to workaround buggy firmware.
646 See Documentation/networking/ipv6.txt.
648 disable_mtrr_cleanup [X86]
649 The kernel tries to adjust MTRR layout from continuous
650 to discrete, to make X server driver able to add WB
651 entry later. This parameter disables that.
653 disable_mtrr_trim [X86, Intel and AMD only]
654 By default the kernel will trim any uncacheable
655 memory out of your available memory pool based on
656 MTRR settings. This parameter disables that behavior,
657 possibly causing your machine to run very slowly.
659 disable_timer_pin_1 [X86]
660 Disable PIN 1 of APIC timer
661 Can be useful to work around chipset bugs.
663 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
664 this option disables the debugging code at boot.
666 dma_debug_entries=<number>
667 This option allows to tune the number of preallocated
668 entries for DMA-API debugging code. One entry is
669 required per DMA-API allocation. Use this if the
670 DMA-API debugging code disables itself because the
671 architectural default is too low.
673 dma_debug_driver=<driver_name>
674 With this option the DMA-API debugging driver
675 filter feature can be enabled at boot time. Just
676 pass the driver to filter for as the parameter.
677 The filter can be disabled or changed to another
678 driver later using sysfs.
682 earlycon= [KNL] Output early console device and options.
683 uart[8250],io,<addr>[,options]
684 uart[8250],mmio,<addr>[,options]
685 uart[8250],mmio32,<addr>[,options]
686 Start an early, polled-mode console on the 8250/16550
687 UART at the specified I/O port or MMIO address.
688 MMIO inter-register address stride is either 8-bit
689 (mmio) or 32-bit (mmio32).
690 The options are the same as for ttyS, above.
692 earlyprintk= [X86,SH,BLACKFIN]
694 earlyprintk=serial[,ttySn[,baudrate]]
695 earlyprintk=ttySn[,baudrate]
696 earlyprintk=dbgp[debugController#]
698 Append ",keep" to not disable it when the real console
701 Only vga or serial or usb debug port at a time.
703 Currently only ttyS0 and ttyS1 are supported.
705 Interaction with the standard serial driver is not
708 The VGA output is eventually overwritten by the real
711 ekgdboc= [X86,KGDB] Allow early kernel console debugging
714 This is designed to be used in conjunction with
715 the boot argument: earlyprintk=vga
718 Format: {"off" | "on" | "skip[mbr]"}
720 eisa_irq_edge= [PARISC,HW]
721 See header of drivers/parisc/eisa.c.
724 See comment before function elanfreq_setup() in
725 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
728 Format: {"cfq" | "deadline" | "noop"}
729 See Documentation/block/as-iosched.txt and
730 Documentation/block/deadline-iosched.txt for details.
732 elfcorehdr= [IA-64,PPC,SH,X86]
733 Specifies physical address of start of kernel core
734 image elf header. Generally kexec loader will
735 pass this option to capture kernel.
736 See Documentation/kdump/kdump.txt for details.
738 enable_mtrr_cleanup [X86]
739 The kernel tries to adjust MTRR layout from continuous
740 to discrete, to make X server driver able to add WB
741 entry later. This parameter enables that.
743 enable_timer_pin_1 [X86]
744 Enable PIN 1 of APIC timer
745 Can be useful to work around chipset bugs
746 (in particular on some ATI chipsets).
747 The kernel tries to set a reasonable default.
749 enforcing [SELINUX] Set initial enforcing status.
751 See security/selinux/Kconfig help text.
752 0 -- permissive (log only, no denials).
753 1 -- enforcing (deny and log).
755 Value can be changed at runtime via /selinux/enforce.
758 Disable Error Record Serialization Table (ERST)
761 ether= [HW,NET] Ethernet cards parameters
762 This option is obsoleted by the "netdev=" option, which
763 has equivalent usage. See its documentation for details.
767 fail_make_request=[KNL]
768 General fault injection mechanism.
769 Format: <interval>,<probability>,<space>,<times>
770 See also /Documentation/fault-injection/.
773 See Documentation/blockdev/floppy.txt.
775 force_pal_cache_flush
776 [IA-64] Avoid check_sal_cache_flush which may hang on
777 buggy SAL_CACHE_FLUSH implementations. Using this
778 parameter will force ia64_sal_cache_flush to call
779 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
782 [FTRACE] will set and start the specified tracer
783 as early as possible in order to facilitate early
786 ftrace_dump_on_oops[=orig_cpu]
787 [FTRACE] will dump the trace buffers on oops.
788 If no parameter is passed, ftrace will dump
789 buffers of all CPUs, but if you pass orig_cpu, it will
790 dump only the buffer of the CPU that triggered the
793 ftrace_filter=[function-list]
794 [FTRACE] Limit the functions traced by the function
795 tracer at boot up. function-list is a comma separated
796 list of functions. This list can be changed at run
797 time by the set_ftrace_filter file in the debugfs
800 ftrace_notrace=[function-list]
801 [FTRACE] Do not trace the functions specified in
802 function-list. This list can be changed at run time
803 by the set_ftrace_notrace file in the debugfs
806 ftrace_graph_filter=[function-list]
807 [FTRACE] Limit the top level callers functions traced
808 by the function graph tracer at boot up.
809 function-list is a comma separated list of functions
810 that can be changed at run time by the
811 set_graph_function file in the debugfs tracing directory.
814 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
815 support via parallel port (up to 5 devices per port)
816 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
817 See also Documentation/input/joystick-parport.txt
821 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
825 gcov_persist= [GCOV] When non-zero (default), profiling data for
826 kernel modules is saved and remains accessible via
827 debugfs, even when the module is unloaded/reloaded.
828 When zero, profiling data is discarded and associated
829 debugfs files are removed at module unload time.
831 gpt [EFI] Forces disk with valid GPT signature but
832 invalid Protective MBR to be treated as GPT.
834 guestdev= [PCI,ACPI,XEN]
835 Format: {<device path>|<sbdf>}][,{<device path>|<sbdf>}[,...]]
836 Format of device path: <hid>[:<uid>]-<dev>.<func>[-<dev>.<func>[,...]][+iomul]
837 Format of sbdf: [<segment>:]<bus>:<dev>.<func>[+iomul]
838 Specifies PCI device for guest domain.
839 If PCI-PCI bridge is specified, all PCI devices
840 behind PCI-PCI bridge are reserved.
841 +iomul means that this PCI function will share
842 IO ports with other +iomul functions under same
843 switch. NOTE: if +iomul is specfied, all the functions
844 of the device will share IO ports.
846 guestiomuldev= [PCI,ACPI,XEN]
847 Format: [sbd][,<sbd>][,...]
848 Format of sbdf: [<segment>:]<bus>:<dev>
849 Note: function shouldn't be specified.
850 Specifies PCI device for IO port multiplexing driver.
852 hashdist= [KNL,NUMA] Large hashes allocated during boot
853 are distributed across NUMA nodes. Defaults on
854 for 64-bit NUMA, off otherwise.
855 Format: 0 | 1 (for off | on)
857 hcl= [IA-64] SGI's Hardware Graph compatibility layer
859 hd= [EIDE] (E)IDE hard drive subsystem geometry
860 Format: <cyl>,<head>,<sect>
863 Disable Hardware Error Source Table (HEST) support;
864 corresponding firmware-first mode error processing
865 logic will be disabled.
867 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
868 size of <nn>. This works even on boxes that have no
869 highmem otherwise. This also works to reduce highmem
870 size on bigger boxes.
872 highres= [KNL] Enable/disable high resolution timer mode.
873 Valid parameters: "on", "off"
877 See Documentation/isdn/README.HiSax.
881 hpet= [X86-32,HPET] option to control HPET usage
882 Format: { enable (default) | disable | force |
884 disable: disable HPET and use PIT instead
885 force: allow force enabled of undocumented chips (ICH4,
887 verbose: show contents of HPET registers during setup
889 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
890 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
891 On x86-64 and powerpc, this option can be specified
892 multiple times interleaved with hugepages= to reserve
893 huge pages of different sizes. Valid pages sizes on
894 x86-64 are 2M (when the CPU supports "pse") and 1G
895 (when the CPU supports the "pdpe1gb" cpuinfo flag)
896 Note that 1GB pages can only be allocated at boot time
897 using hugepages= and not freed afterwards.
899 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
900 terminal devices. Valid values: 0..8
901 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
902 If specified, z/VM IUCV HVC accepts connections
903 from listed z/VM user IDs only.
906 Do not unregister boot console at start. This is only
907 useful for debugging when something happens in the window
908 between unregistering the boot console and initializing
911 i2c_bus= [HW] Override the default board specific I2C bus speed
912 or register an additional I2C bus that is not
913 registered from board initialization code.
917 i8042.debug [HW] Toggle i8042 debug mode
918 i8042.direct [HW] Put keyboard port into non-translated mode
919 i8042.dumbkbd [HW] Pretend that controller can only read data from
920 keyboard and cannot control its state
921 (Don't attempt to blink the leds)
922 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
923 i8042.nokbd [HW] Don't check/create keyboard port
924 i8042.noloop [HW] Disable the AUX Loopback command while probing
926 i8042.nomux [HW] Don't check presence of an active multiplexing
928 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
930 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
931 i8042.reset [HW] Reset the controller during init and cleanup
932 i8042.unlock [HW] Unlock (ignore) the keylock
936 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
937 indicates that the driver is running on unsupported
939 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
940 does not match list of supported models.
942 [HW] Report power status in /proc/i8k
943 (disabled by default)
944 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
948 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
950 ide-core.nodma= [HW] (E)IDE subsystem
951 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
952 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
953 .cdrom .chs .ignore_cable are additional options
954 See Documentation/ide/ide.txt.
956 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
957 Claim all unknown PCI IDE storage controllers.
960 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
961 Poll forces a polling idle loop that can slightly
962 improve the performance of waking up a idle CPU, but
963 will use a lot of power and make the system run hot.
965 idle=mwait: On systems which support MONITOR/MWAIT but
966 the kernel chose to not use it because it doesn't save
967 as much power as a normal idle loop, use the
968 MONITOR/MWAIT idle loop anyways. Performance should be
969 the same as idle=poll.
970 idle=halt: Halt is forced to be used for CPU idle.
971 In such case C2/C3 won't be used again.
972 idle=nomwait: Disable mwait for CPU C-states
974 ignore_loglevel [KNL]
975 Ignore loglevel setting - this will print /all/
976 kernel messages to the console. Useful for debugging.
979 Set number of hash buckets for inode cache.
982 Format: { "0" | "1" }
983 0 -- integrity auditing messages. (Default)
984 1 -- enable informational integrity auditing messages.
987 Format: { "sha1" | "md5" }
991 Load a policy which meets the needs of the Trusted
992 Computing Base. This means IMA will measure all
993 programs exec'd, files mmap'd for exec, and all files
994 opened for read by uid=0.
998 Run specified binary instead of /sbin/init as init
1001 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1002 for working out where the kernel is dying during
1005 initrd= [BOOT] Specify the location of the initial ramdisk
1007 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1010 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1012 Enable intel iommu driver.
1014 Disable intel iommu driver.
1015 igfx_off [Default Off]
1016 By default, gfx is mapped as normal device. If a gfx
1017 device has a dedicated DMAR unit, the DMAR unit is
1018 bypassed by not enabling DMAR with this option. In
1019 this case, gfx device will use physical address for
1022 With this option iommu will not optimize to look
1023 for io virtual address below 32-bit forcing dual
1024 address cycle on pci bus for cards supporting greater
1025 than 32-bit addressing. The default is to look
1026 for translation below 32-bit and if not available
1027 then look in the higher range.
1028 strict [Default Off]
1029 With this option on every unmap_single operation will
1030 result in a hardware IOTLB flush operation as opposed
1031 to batching them for performance.
1032 sp_off [Default Off]
1033 By default, super page will be supported if Intel IOMMU
1034 has the capability. With this option, super page will
1036 intremap= [X86-64, Intel-IOMMU]
1037 Format: { on (default) | off | nosid }
1038 on enable Interrupt Remapping (default)
1039 off disable Interrupt Remapping
1040 nosid disable Source ID checking
1044 iomem= Disable strict checking of access to MMIO memory
1045 strict regions from userspace.
1061 io7= [HW] IO7 for Marvel based alpha systems
1062 See comment before marvel_specify_io7 in
1063 arch/alpha/kernel/core_marvel.c.
1065 io_delay= [X86] I/O delay method
1067 Standard port 0x80 based delay
1069 Alternate port 0xed based delay (needed on some systems)
1071 Simple two microseconds delay
1076 See Documentation/filesystems/nfs/nfsroot.txt.
1078 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1079 See comment before ip2_setup() in
1080 drivers/char/ip2/ip2base.c.
1083 When an interrupt is not handled search all handlers
1084 for it. Intended to get systems with badly broken
1088 When an interrupt is not handled search all handlers
1089 for it. Also check all handlers each timer
1090 interrupt. Intended to get systems with badly broken
1094 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1096 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1098 <cpu number>,...,<cpu number>
1100 <cpu number>-<cpu number>
1101 (must be a positive range in ascending order)
1103 <cpu number>,...,<cpu number>-<cpu number>
1105 This option can be used to specify one or more CPUs
1106 to isolate from the general SMP balancing and scheduling
1107 algorithms. You can move a process onto or off an
1108 "isolated" CPU via the CPU affinity syscalls or cpuset.
1109 <cpu number> begins at 0 and the maximum value is
1110 "number of CPUs in system - 1".
1112 This option is the preferred way to isolate CPUs. The
1113 alternative -- manually setting the CPU mask of all
1114 tasks in the system -- can cause problems and
1115 suboptimal load balancer performance.
1119 js= [HW,JOY] Analog joystick
1120 See Documentation/input/joystick.txt.
1124 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1125 specifies the amount of memory usable by the kernel
1126 for non-movable allocations. The requested amount is
1127 spread evenly throughout all nodes in the system. The
1128 remaining memory in each node is used for Movable
1129 pages. In the event, a node is too small to have both
1130 kernelcore and Movable pages, kernelcore pages will
1131 take priority and other nodes will have a larger number
1132 of kernelcore pages. The Movable zone is used for the
1133 allocation of pages that may be reclaimed or moved
1134 by the page migration subsystem. This means that
1135 HugeTLB pages may not be allocated from this zone.
1136 Note that allocations like PTEs-from-HighMem still
1137 use the HighMem zone if it exists, and the Normal
1138 zone if it does not.
1140 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1141 Format: <Controller#>[,poll interval]
1142 The controller # is the number of the ehci usb debug
1143 port as it is probed via PCI. The poll interval is
1144 optional and is the number seconds in between
1145 each poll cycle to the debug port in case you need
1146 the functionality for interrupting the kernel with
1147 gdb or control-c on the dbgp connection. When
1148 not using this parameter you use sysrq-g to break into
1149 the kernel debugger.
1151 kgdboc= [KGDB,HW] kgdb over consoles.
1152 Requires a tty driver that supports console polling,
1153 or a supported polling keyboard driver (non-usb).
1154 Serial only format: <serial_device>[,baud]
1155 keyboard only format: kbd
1156 keyboard and serial format: kbd,<serial_device>[,baud]
1157 Optional Kernel mode setting:
1158 kms, kbd format: kms,kbd
1159 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1161 kgdbwait [KGDB] Stop kernel execution and enter the
1162 kernel debugger at the earliest opportunity.
1164 kmac= [MIPS] korina ethernet MAC address.
1165 Configure the RouterBoard 532 series on-chip
1166 Ethernet adapter MAC address.
1168 kmemleak= [KNL] Boot-time kmemleak enable/disable
1169 Valid arguments: on, off
1172 kstack=N [X86] Print N words from the kernel stack
1175 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1176 Default is 0 (don't ignore, but inject #GP)
1178 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1179 Default is 1 (enabled)
1181 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1185 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1186 Default is 1 (enabled)
1188 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1190 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1192 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1193 (virtualized MMU) support on capable Intel chips.
1194 Default is 1 (enabled)
1196 kvm-intel.emulate_invalid_guest_state=
1197 [KVM,Intel] Enable emulation of invalid guest states
1198 Default is 0 (disabled)
1200 kvm-intel.flexpriority=
1201 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1202 Default is 1 (enabled)
1204 kvm-intel.unrestricted_guest=
1205 [KVM,Intel] Disable unrestricted guest feature
1206 (virtualized real and unpaged mode) on capable
1207 Intel chips. Default is 1 (enabled)
1209 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1210 feature (tagged TLBs) on capable Intel chips.
1211 Default is 1 (enabled)
1217 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1220 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1223 libata.dma= [LIBATA] DMA control
1224 libata.dma=0 Disable all PATA and SATA DMA
1225 libata.dma=1 PATA and SATA Disk DMA only
1226 libata.dma=2 ATAPI (CDROM) DMA only
1227 libata.dma=4 Compact Flash DMA only
1228 Combinations also work, so libata.dma=3 enables DMA
1229 for disks and CDROMs, but not CFs.
1231 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1232 libata.ignore_hpa=0 keep BIOS limits (default)
1233 libata.ignore_hpa=1 ignore limits, using full disk
1235 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1239 libata.force= [LIBATA] Force configurations. The format is comma
1240 separated list of "[ID:]VAL" where ID is
1241 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1242 matching port, link or device. Basically, it matches
1243 the ATA ID string printed on console by libata. If
1244 the whole ID part is omitted, the last PORT and DEVICE
1245 values are used. If ID hasn't been specified yet, the
1246 configuration applies to all ports, links and devices.
1248 If only DEVICE is omitted, the parameter applies to
1249 the port and all links and devices behind it. DEVICE
1250 number of 0 either selects the first device or the
1251 first fan-out link behind PMP device. It does not
1252 select the host link. DEVICE number of 15 selects the
1253 host link and device attached to it.
1255 The VAL specifies the configuration to force. As long
1256 as there's no ambiguity shortcut notation is allowed.
1257 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1258 The following configurations can be forced.
1260 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1261 Any ID with matching PORT is used.
1263 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1265 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1266 udma[/][16,25,33,44,66,100,133] notation is also
1269 * [no]ncq: Turn on or off NCQ.
1271 * nohrst, nosrst, norst: suppress hard, soft
1274 * dump_id: dump IDENTIFY data.
1276 If there are multiple matching configurations changing
1277 the same attribute, the last one is used.
1279 memblock=debug [KNL] Enable memblock debug messages.
1281 load_ramdisk= [RAM] List of ramdisks to load from floppy
1282 See Documentation/blockdev/ramdisk.txt.
1284 lockd.nlm_grace_period=P [NFS] Assign grace period.
1287 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1290 lockd.nlm_timeout=T [NFS] Assign timeout value.
1293 lockd.nlm_udpport=M [NFS] Assign UDP port.
1296 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1299 loglevel= All Kernel Messages with a loglevel smaller than the
1300 console loglevel will be printed to the console. It can
1301 also be changed with klogd or other programs. The
1302 loglevels are defined as follows:
1304 0 (KERN_EMERG) system is unusable
1305 1 (KERN_ALERT) action must be taken immediately
1306 2 (KERN_CRIT) critical conditions
1307 3 (KERN_ERR) error conditions
1308 4 (KERN_WARNING) warning conditions
1309 5 (KERN_NOTICE) normal but significant condition
1310 6 (KERN_INFO) informational
1311 7 (KERN_DEBUG) debug-level messages
1313 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1314 in bytes. n must be a power of two. The default
1315 size is set in the kernel config file.
1317 logo.nologo [FB] Disables display of the built-in Linux logo.
1318 This may be used to provide more screen space for
1319 kernel log messages and is useful when debugging
1320 kernel boot problems.
1322 lp=0 [LP] Specify parallel ports to use, e.g,
1323 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1324 lp=reset first parallel port). 'lp=0' disables the
1325 lp=auto printer driver. 'lp=reset' (which can be
1326 specified in addition to the ports) causes
1327 attached printers to be reset. Using
1328 lp=port1,port2,... specifies the parallel ports
1329 to associate lp devices with, starting with
1330 lp0. A port specification may be 'none' to skip
1331 that lp device, or a parport name such as
1332 'parport0'. Specifying 'lp=auto' instead of a
1333 port specification list means that device IDs
1334 from each port should be examined, to see if
1335 an IEEE 1284-compliant printer is attached; if
1336 so, the driver will manage that printer.
1337 See also header of drivers/char/lp.c.
1340 Sets loops_per_jiffy to given constant, thus avoiding
1341 time-consuming boot-time autodetection (up to 250 ms per
1342 CPU). 0 enables autodetection (default). To determine
1343 the correct value for your kernel, boot with normal
1344 autodetection and see what value is printed. Note that
1345 on SMP systems the preset will be applied to all CPUs,
1346 which is likely to cause problems if your CPUs need
1347 significantly divergent settings. An incorrect value
1348 will cause delays in the kernel to be wrong, leading to
1349 unpredictable I/O errors and other breakage. Although
1350 unlikely, in the extreme case this might damage your
1354 Format: <io>,<irq>,<dma>
1356 machvec= [IA-64] Force the use of a particular machine-vector
1357 (machvec) in a generic kernel.
1358 Example: machvec=hpzx1_swiotlb
1360 machtype= [Loongson] Share the same kernel image file between different
1362 Example: machtype=lemote-yeeloong-2f-7inch
1364 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1365 than or equal to this physical address is ignored.
1367 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1368 should make use of. maxcpus=n : n >= 0 limits the
1369 kernel to using 'n' processors. n=0 is a special case,
1370 it is equivalent to "nosmp", which also disables
1373 max_loop= [LOOP] The number of loop block devices that get
1374 (loop.max_loop) unconditionally pre-created at init time. The default
1375 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1376 of statically allocating a predefined number, loop
1377 devices can be requested on-demand with the
1378 /dev/loop-control interface.
1382 mce [X86-32] Machine Check Exception
1384 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1386 md= [HW] RAID subsystems devices and level
1387 See Documentation/md.txt.
1390 Format: <first>,<last>
1391 Specifies range of consoles to be captured by the MDA.
1393 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1394 Amount of memory to be used when the kernel is not able
1395 to see the whole system memory or for test.
1396 [X86-32] Use together with memmap= to avoid physical
1397 address space collisions. Without memmap= PCI devices
1398 could be placed at addresses belonging to unused RAM.
1400 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1404 [KNL,SH] Allow user to override the default size for
1405 per-device physically contiguous DMA buffers.
1407 memmap=exactmap [KNL,X86] Enable setting of an exact
1408 E820 memory map, as specified by the user.
1409 Such memmap=exactmap lines can be constructed based on
1410 BIOS output or other requirements. See the memmap=nn@ss
1413 memmap=nn[KMG]@ss[KMG]
1414 [KNL] Force usage of a specific region of memory
1415 Region of memory to be used, from ss to ss+nn.
1417 memmap=nn[KMG]#ss[KMG]
1418 [KNL,ACPI] Mark specific memory as ACPI data.
1419 Region of memory to be used, from ss to ss+nn.
1421 memmap=nn[KMG]$ss[KMG]
1422 [KNL,ACPI] Mark specific memory as reserved.
1423 Region of memory to be used, from ss to ss+nn.
1424 Example: Exclude memory from 0x18690000-0x1869ffff
1425 memmap=64K$0x18690000
1427 memmap=0x10000$0x18690000
1429 memory_corruption_check=0/1 [X86]
1430 Some BIOSes seem to corrupt the first 64k of
1431 memory when doing things like suspend/resume.
1432 Setting this option will scan the memory
1433 looking for corruption. Enabling this will
1434 both detect corruption and prevent the kernel
1435 from using the memory being corrupted.
1436 However, its intended as a diagnostic tool; if
1437 repeatable BIOS-originated corruption always
1438 affects the same memory, you can use memmap=
1439 to prevent the kernel from using that memory.
1441 memory_corruption_check_size=size [X86]
1442 By default it checks for corruption in the low
1443 64k, making this memory unavailable for normal
1444 use. Use this parameter to scan for
1445 corruption in more or less memory.
1447 memory_corruption_check_period=seconds [X86]
1448 By default it checks for corruption every 60
1449 seconds. Use this parameter to check at some
1450 other rate. 0 disables periodic checking.
1452 memtest= [KNL,X86] Enable memtest
1454 default : 0 <disable>
1455 Specifies the number of memtest passes to be
1456 performed. Each pass selects another test
1457 pattern from a given set of patterns. Memtest
1458 fills the memory with this pattern, validates
1459 memory contents and reserves bad memory
1460 regions that are detected.
1462 meye.*= [HW] Set MotionEye Camera parameters
1463 See Documentation/video4linux/meye.txt.
1465 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1466 Multi-Function General Purpose Timers on AMD Geode
1469 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1470 the BIOS has incorrectly applied a workaround. TinyBIOS
1471 version 0.98 is known to be affected, 0.99 fixes the
1472 problem by letting the user disable the workaround.
1476 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1477 physical address is ignored.
1479 mini2440= [ARM,HW,KNL]
1480 Format:[0..2][b][c][t]
1482 MINI2440 configuration specification:
1483 0 - The attached screen is the 3.5" TFT
1484 1 - The attached screen is the 7" TFT
1485 2 - The VGA Shield is attached (1024x768)
1486 Leaving out the screen size parameter will not load
1487 the TFT driver, and the framebuffer will be left
1489 b - Enable backlight. The TFT backlight pin will be
1490 linked to the kernel VESA blanking code and a GPIO
1491 LED. This parameter is not necessary when using the
1493 c - Enable the s3c camera interface.
1494 t - Reserved for enabling touchscreen support. The
1495 touchscreen support is not enabled in the mainstream
1496 kernel as of 2.6.30, a preliminary port can be found
1497 in the "bleeding edge" mini2440 support kernel at
1498 http://repo.or.cz/w/linux-2.6/mini2440.git
1501 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1502 parameter allows control of the logging verbosity for
1503 the additional memory initialisation checks. A value
1504 of 0 disables mminit logging and a level of 4 will
1505 log everything. Information is printed at KERN_DEBUG
1506 so loglevel=8 may also need to be specified.
1509 [MOUSE] Maximum time between finger touching and
1510 leaving touchpad surface for touch to be considered
1511 a tap and be reported as a left button click (for
1512 touchpads working in absolute mode only).
1514 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1515 reporting absolute coordinates, such as tablets
1516 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1517 reporting absolute coordinates, such as tablets
1519 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1520 is similar to kernelcore except it specifies the
1521 amount of memory used for migratable allocations.
1522 If both kernelcore and movablecore is specified,
1523 then kernelcore will be at *least* the specified
1524 value but may be more. If movablecore on its own
1525 is specified, the administrator must be careful
1526 that the amount of memory usable for all allocations
1529 MTD_Partition= [MTD]
1530 Format: <name>,<region-number>,<size>,<offset>
1532 MTD_Region= [MTD] Format:
1533 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1536 See drivers/mtd/cmdlinepart.c.
1538 multitce=off [PPC] This parameter disables the use of the pSeries
1539 firmware feature for updating multiple TCE entries
1542 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1544 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1546 boundary - index of last SLC block on Flex-OneNAND.
1547 The remaining blocks are configured as MLC blocks.
1548 lock - Configure if Flex-OneNAND boundary should be locked.
1549 Once locked, the boundary cannot be changed.
1550 1 indicates lock status, 0 indicates unlock status.
1553 ARM/S3C2412 JIVE boot control
1555 See arch/arm/mach-s3c2412/mach-jive.c
1557 mtouchusb.raw_coordinates=
1558 [HW] Make the MicroTouch USB driver use raw coordinates
1559 ('y', default) or cooked coordinates ('n')
1561 mtrr_chunk_size=nn[KMG] [X86]
1562 used for mtrr cleanup. It is largest continuous chunk
1563 that could hold holes aka. UC entries.
1565 mtrr_gran_size=nn[KMG] [X86]
1566 Used for mtrr cleanup. It is granularity of mtrr block.
1568 Large value could prevent small alignment from
1571 mtrr_spare_reg_nr=n [X86]
1573 Range: 0,7 : spare reg number
1575 Used for mtrr cleanup. It is spare mtrr entries number.
1576 Set to 2 or more if your graphical card needs more.
1578 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1580 netdev= [NET] Network devices parameters
1581 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1582 Note that mem_start is often overloaded to mean
1583 something different and driver-specific.
1584 This usage is only documented in each driver source
1588 [NETFILTER] Enable connection tracking flow accounting
1589 0 to disable accounting
1590 1 to enable accounting
1593 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1594 See Documentation/filesystems/nfs/nfsroot.txt.
1596 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1597 See Documentation/filesystems/nfs/nfsroot.txt.
1599 nfsrootdebug [NFS] enable nfsroot debugging messages.
1600 See Documentation/filesystems/nfs/nfsroot.txt.
1602 nfs.callback_tcpport=
1603 [NFS] set the TCP port on which the NFSv4 callback
1604 channel should listen.
1607 [NFS] sets the pathname to the program which is used
1608 to update the NFS client cache entries.
1610 nfs.cache_getent_timeout=
1611 [NFS] sets the timeout after which an attempt to
1612 update a cache entry is deemed to have failed.
1614 nfs.idmap_cache_timeout=
1615 [NFS] set the maximum lifetime for idmapper cache
1619 [NFS] enable 64-bit inode numbers.
1620 If zero, the NFS client will fake up a 32-bit inode
1621 number for the readdir() and stat() syscalls instead
1622 of returning the full 64-bit number.
1623 The default is to return 64-bit inode numbers.
1625 nfs.nfs4_disable_idmapping=
1626 [NFSv4] When set, this option disables the NFSv4
1627 idmapper on the client, but only if the mount
1628 is using the 'sec=sys' security flavour. This may
1629 make migration from legacy NFSv2/v3 systems easier
1630 provided that the server has the appropriate support.
1631 The default is to always enable NFSv4 idmapping.
1633 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1634 when a NMI is triggered.
1635 Format: [state][,regs][,debounce][,die]
1637 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1638 Format: [panic,][nopanic,][num]
1640 0 - turn nmi_watchdog off
1641 When panic is specified, panic when an NMI watchdog
1642 timeout occurs (or 'nopanic' to override the opposite
1644 This is useful when you use a panic=... timeout and
1645 need the box quickly up again.
1647 netpoll.carrier_timeout=
1648 [NET] Specifies amount of time (in seconds) that
1649 netpoll should wait for a carrier. By default netpoll
1652 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1653 emulation library even if a 387 maths coprocessor
1657 [HW] Never suspend the console
1658 Disable suspending of consoles during suspend and
1659 hibernate operations. Once disabled, debugging
1660 messages can reach various consoles while the rest
1661 of the system is being put to sleep (ie, while
1662 debugging driver suspend/resume hooks). This may
1663 not work reliably with all consoles, but is known
1664 to work with serial and VGA consoles.
1666 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1667 caches in the slab allocator. Saves per-node memory,
1668 but will impact performance.
1672 noapic [SMP,APIC] Tells the kernel to not make use of any
1673 IOAPICs that may be present in the system.
1675 noautogroup Disable scheduler automatic task group creation.
1677 nobats [PPC] Do not use BATs for mapping kernel lowmem
1678 on "Classic" PPC cores.
1682 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1684 nodelayacct [KNL] Disable per-task delay accounting
1686 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1688 nodsp [SH] Disable hardware DSP at boot time.
1690 noefi [X86] Disable EFI runtime services support.
1695 On X86-32 available only on PAE configured kernels.
1696 noexec=on: enable non-executable mappings (default)
1697 noexec=off: disable non-executable mappings
1700 Disable SMEP (Supervisor Mode Execution Protection)
1701 even if it is supported by processor.
1704 This affects only 32-bit executables.
1705 noexec32=on: enable non-executable mappings (default)
1706 read doesn't imply executable mappings
1707 noexec32=off: disable non-executable mappings
1708 read implies executable mappings
1710 nofpu [SH] Disable hardware FPU at boot time.
1712 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1713 register save and restore. The kernel will only save
1714 legacy floating-point registers on task switch.
1716 noxsave [BUGS=X86] Disables x86 extended register state save
1717 and restore using xsave. The kernel will fallback to
1718 enabling legacy floating-point and sse state.
1720 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1721 wfi(ARM) instruction doesn't work correctly and not to
1722 use it. This is also useful when using JTAG debugger.
1724 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1725 instruction doesn't work correctly and not to
1728 no_file_caps Tells the kernel not to honor file capabilities. The
1729 only way then for a file to be executed with privilege
1730 is to be setuid root or executed by root.
1732 nohalt [IA-64] Tells the kernel not to use the power saving
1733 function PAL_HALT_LIGHT when idle. This increases
1734 power-consumption. On the positive side, it reduces
1735 interrupt wake-up latency, which may improve performance
1736 in certain environments such as networked servers or
1739 nohz= [KNL] Boottime enable/disable dynamic ticks
1740 Valid arguments: on, off
1743 noiotrap [SH] Disables trapped I/O port accesses.
1745 noirqdebug [X86-32] Disables the code which attempts to detect and
1746 disable unhandled interrupt sources.
1748 no_timer_check [X86,APIC] Disables the code which tests for
1749 broken timer IRQ sources.
1751 noisapnp [ISAPNP] Disables ISA PnP code.
1753 noinitrd [RAM] Tells the kernel not to load any configured
1756 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1758 [Deprecated - use intremap=off]
1762 nojitter [IA-64] Disables jitter checking for ITC timers.
1764 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1766 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1769 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1770 steal time is computed, but won't influence scheduler
1773 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1775 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1777 noltlbs [PPC] Do not use large page/tlb entries for kernel
1778 lowmem mapping on PPC40x.
1780 nomca [IA-64] Disable machine check abort handling
1782 nomce [X86-32] Machine Check Exception
1784 nomfgpt [X86-32] Disable Multi-Function General Purpose
1785 Timer usage (for AMD Geode machines).
1787 nopat [X86] Disable PAT (page attribute table extension of
1788 pagetables) support.
1790 norandmaps Don't use address space randomization. Equivalent to
1791 echo 0 > /proc/sys/kernel/randomize_va_space
1793 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1795 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1796 with UP alternatives
1798 noresidual [PPC] Don't use residual data on PReP machines.
1800 noresume [SWSUSP] Disables resume and restores original swap
1803 no-scroll [VGA] Disables scrollback.
1804 This is required for the Braillex ib80-piezo Braille
1805 reader made by F.H. Papenmeier (Germany).
1809 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1811 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1812 and disable the IO APIC. legacy for "maxcpus=0".
1814 nosoftlockup [KNL] Disable the soft-lockup detector.
1816 nosync [HW,M68K] Disables sync negotiation for all devices.
1818 notsc [BUGS=X86-32] Disable Time Stamp Counter
1820 nousb [USB] Disable the USB subsystem
1822 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1826 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1828 nptcg= [IA-64] Override max number of concurrent global TLB
1829 purges which is reported from either PAL_VM_SUMMARY or
1832 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1833 could support. nr_cpus=n : n >= 1 limits the kernel to
1834 supporting 'n' processors. Later in runtime you can not
1835 use hotplug cpu feature to put more cpu back to online.
1836 just like you compile the kernel NR_CPUS=n
1838 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1840 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1841 one of ['zone', 'node', 'default'] can be specified
1842 This can be set from sysctl after boot.
1843 See Documentation/sysctl/vm.txt for details.
1845 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1846 See Documentation/debugging-via-ohci1394.txt for more
1849 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1850 Rather than timing out after 20 ms if an EC
1851 command is not properly ACKed, override the length
1852 of the timeout. We have interrupts disabled while
1853 waiting for the ACK, so if this is set too high
1854 interrupts *may* be lost!
1856 omap_mux= [OMAP] Override bootloader pin multiplexing.
1857 Format: <mux_mode0.mode_name=value>...
1858 For example, to override I2C bus2:
1859 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1861 oprofile.timer= [HW]
1862 Use timer interrupt instead of performance counters
1864 oprofile.cpu_type= Force an oprofile cpu type
1865 This might be useful if you have an older oprofile
1866 userland or if you want common events.
1867 Format: { arch_perfmon }
1868 arch_perfmon: [X86] Force use of architectural
1869 perfmon on Intel CPUs instead of the
1870 CPU specific event set.
1872 oops=panic Always panic on oopses. Default is to just kill the
1873 process, but there is a small probability of
1874 deadlocking the machine.
1875 This will also cause panics on machine check exceptions.
1876 Useful together with panic=30 to trigger a reboot.
1879 See Documentation/sound/oss/oss-parameters.txt
1881 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1882 timeout > 0: seconds before rebooting
1883 timeout = 0: wait forever
1884 timeout < 0: reboot immediately
1887 parkbd.port= [HW] Parallel port number the keyboard adapter is
1888 connected to, default is 0.
1890 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1891 0 for XT, 1 for AT (default is AT).
1894 parport= [HW,PPT] Specify parallel ports. 0 disables.
1895 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1896 Use 'auto' to force the driver to use any
1897 IRQ/DMA settings detected (the default is to
1898 ignore detected IRQ/DMA settings because of
1899 possible conflicts). You can specify the base
1900 address, IRQ, and DMA settings; IRQ and DMA
1901 should be numbers, or 'auto' (for using detected
1902 settings on that particular port), or 'nofifo'
1903 (to avoid using a FIFO even if it is detected).
1904 Parallel ports are assigned in the order they
1905 are specified on the command line, starting
1908 parport_init_mode= [HW,PPT]
1909 Configure VIA parallel port to operate in
1910 a specific mode. This is necessary on Pegasos
1911 computer where firmware has no options for setting
1912 up parallel port mode and sets it to spp.
1913 Currently this function knows 686a and 8231 chips.
1914 Format: [spp|ps2|epp|ecp|ecpepp]
1917 Halt all CPUs after the first oops has been printed for
1918 the specified number of seconds. This is to be used if
1919 your oopses keep scrolling off the screen.
1924 See header of drivers/block/paride/pcd.c.
1925 See also Documentation/blockdev/paride.txt.
1927 pci=option[,option...] [PCI] various PCI subsystem options:
1928 earlydump [X86] dump PCI config space before the kernel
1930 off [X86] don't probe for the PCI bus
1931 bios [X86-32] force use of PCI BIOS, don't access
1932 the hardware directly. Use this if your machine
1933 has a non-standard PCI host bridge.
1934 nobios [X86-32] disallow use of PCI BIOS, only direct
1935 hardware access methods are allowed. Use this
1936 if you experience crashes upon bootup and you
1937 suspect they are caused by the BIOS.
1938 conf1 [X86] Force use of PCI Configuration
1940 conf2 [X86] Force use of PCI Configuration
1942 noaer [PCIE] If the PCIEAER kernel config parameter is
1943 enabled, this kernel boot option can be used to
1944 disable the use of PCIE advanced error reporting.
1945 nodomains [PCI] Disable support for multiple PCI
1946 root domains (aka PCI segments, in ACPI-speak).
1947 nommconf [X86] Disable use of MMCONFIG for PCI
1949 check_enable_amd_mmconf [X86] check for and enable
1950 properly configured MMIO access to PCI
1951 config space on AMD family 10h CPU
1952 nomsi [MSI] If the PCI_MSI kernel config parameter is
1953 enabled, this kernel boot option can be used to
1954 disable the use of MSI interrupts system-wide.
1955 noioapicquirk [APIC] Disable all boot interrupt quirks.
1956 Safety option to keep boot IRQs enabled. This
1957 should never be necessary.
1958 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1959 primary IO-APIC for bridges that cannot disable
1960 boot IRQs. This fixes a source of spurious IRQs
1961 when the system masks IRQs.
1962 noioapicreroute [APIC] Disable workaround that uses the
1963 boot IRQ equivalent of an IRQ that connects to
1964 a chipset where boot IRQs cannot be disabled.
1965 The opposite of ioapicreroute.
1966 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1967 routing table. These calls are known to be buggy
1968 on several machines and they hang the machine
1969 when used, but on other computers it's the only
1970 way to get the interrupt routing table. Try
1971 this option if the kernel is unable to allocate
1972 IRQs or discover secondary PCI buses on your
1974 rom [X86] Assign address space to expansion ROMs.
1975 Use with caution as certain devices share
1976 address decoders between ROMs and other
1978 norom [X86] Do not assign address space to
1979 expansion ROMs that do not already have
1980 BIOS assigned address ranges.
1981 nobar [X86] Do not assign address space to the
1982 BARs that weren't assigned by the BIOS.
1983 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1984 assigned automatically to PCI devices. You can
1985 make the kernel exclude IRQs of your ISA cards
1987 pirqaddr=0xAAAAA [X86] Specify the physical address
1988 of the PIRQ table (normally generated
1989 by the BIOS) if it is outside the
1990 F0000h-100000h range.
1991 lastbus=N [X86] Scan all buses thru bus #N. Can be
1992 useful if the kernel is unable to find your
1993 secondary buses and you want to tell it
1994 explicitly which ones they are.
1995 assign-busses [X86] Always assign all PCI bus
1996 numbers ourselves, overriding
1997 whatever the firmware may have done.
1998 usepirqmask [X86] Honor the possible IRQ mask stored
1999 in the BIOS $PIR table. This is needed on
2000 some systems with broken BIOSes, notably
2001 some HP Pavilion N5400 and Omnibook XE3
2002 notebooks. This will have no effect if ACPI
2003 IRQ routing is enabled.
2004 noacpi [X86] Do not use ACPI for IRQ routing
2005 or for PCI scanning.
2006 use_crs [X86] Use PCI host bridge window information
2007 from ACPI. On BIOSes from 2008 or later, this
2008 is enabled by default. If you need to use this,
2009 please report a bug.
2010 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2011 If you need to use this, please report a bug.
2012 routeirq Do IRQ routing for all PCI devices.
2013 This is normally done in pci_enable_device(),
2014 so this option is a temporary workaround
2015 for broken drivers that don't call it.
2016 skip_isa_align [X86] do not align io start addr, so can
2017 handle more pci cards
2018 firmware [ARM] Do not re-enumerate the bus but instead
2019 just use the configuration from the
2020 bootloader. This is currently used on
2021 IXP2000 systems where the bus has to be
2022 configured a certain way for adjunct CPUs.
2023 noearly [X86] Don't do any early type 1 scanning.
2024 This might help on some broken boards which
2025 machine check when some devices' config space
2026 is read. But various workarounds are disabled
2027 and some IOMMU drivers will not work.
2028 bfsort Sort PCI devices into breadth-first order.
2029 This sorting is done to get a device
2030 order compatible with older (<= 2.4) kernels.
2031 nobfsort Don't sort PCI devices into breadth-first order.
2032 cbiosize=nn[KMG] The fixed amount of bus space which is
2033 reserved for the CardBus bridge's IO window.
2034 The default value is 256 bytes.
2035 cbmemsize=nn[KMG] The fixed amount of bus space which is
2036 reserved for the CardBus bridge's memory
2037 window. The default value is 64 megabytes.
2040 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2041 Specifies alignment and device to reassign
2042 aligned memory resources.
2043 If <order of align> is not specified,
2044 PAGE_SIZE is used as alignment.
2045 PCI-PCI bridge can be specified, if resource
2046 windows need to be expanded.
2047 ecrc= Enable/disable PCIe ECRC (transaction layer
2048 end-to-end CRC checking).
2049 bios: Use BIOS/firmware settings. This is the
2053 realloc reallocate PCI resources if allocations done by BIOS
2057 Format: [<sbdf>[+IO<size>][+MEM<size>]][,<sbdf>...]
2058 Format of sbdf: [<segment>:]<bus>:<dev>.<func>
2059 Specifies the least reserved io size or memory size
2060 which is assigned to PCI bridge even when no child
2061 pci device exists. This is useful with PCI hotplug.
2063 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2066 force Enable ASPM even on devices that claim not to support it.
2067 WARNING: Forcing ASPM on may cause system lockups.
2069 pcie_ports= [PCIE] PCIe ports handling:
2070 auto Ask the BIOS whether or not to use native PCIe services
2071 associated with PCIe ports (PME, hot-plug, AER). Use
2072 them only if that is allowed by the BIOS.
2073 native Use native PCIe services associated with PCIe ports
2075 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2078 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2079 nomsi Do not use MSI for native PCIe PME signaling (this makes
2080 all PCIe root ports use INTx for all services).
2082 pcmv= [HW,PCMCIA] BadgePAD 4
2085 See Documentation/blockdev/paride.txt.
2087 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2090 See arch/parisc/kernel/pdc_chassis.c
2092 percpu_alloc= Select which percpu first chunk allocator to use.
2093 Currently supported values are "embed" and "page".
2094 Archs may support subset or none of the selections.
2095 See comments in mm/percpu.c for details on each
2096 allocator. This parameter is primarily for debugging
2097 and performance comparison.
2100 See Documentation/blockdev/paride.txt.
2103 See Documentation/blockdev/paride.txt.
2105 pirq= [SMP,APIC] Manual mp-table setup
2106 See Documentation/x86/i386/IO-APIC.txt.
2108 plip= [PPT,NET] Parallel port network link
2109 Format: { parport<nr> | timid | 0 }
2110 See also Documentation/parport.txt.
2112 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2113 Override pmtimer IOPort with a hex value.
2117 Enable PNP debug messages (depends on the
2118 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2119 via /sys/module/pnp/parameters/debug. We always show
2120 current resource usage; turning this on also shows
2121 possible settings and some assignment information.
2127 { on | off | curr | res | no-curr | no-res }
2130 [ISAPNP] Exclude IRQs for the autoconfiguration
2133 [ISAPNP] Exclude DMAs for the autoconfiguration
2135 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2136 Ranges are in pairs (I/O port base and size).
2139 [ISAPNP] Exclude memory regions for the
2141 Ranges are in pairs (memory base and size).
2143 ports= [IP_VS_FTP] IPVS ftp helper module
2145 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2147 Format: <port>,<port>....
2149 print-fatal-signals=
2150 [KNL] debug: print fatal signals
2152 If enabled, warn about various signal handling
2153 related application anomalies: too many signals,
2154 too many POSIX.1 timers, fatal signals causing a
2157 If you hit the warning due to signal overflow,
2158 you might want to try "ulimit -i unlimited".
2162 printk.time= Show timing data prefixed to each printk message line
2163 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2165 processor.max_cstate= [HW,ACPI]
2166 Limit processor to maximum C-state
2167 max_cstate=9 overrides any DMI blacklist limit.
2169 processor.nocst [HW,ACPI]
2170 Ignore the _CST method to determine C-states,
2171 instead using the legacy FADT method
2173 profile= [KNL] Enable kernel profiling via /proc/profile
2174 Format: [schedule,]<number>
2175 Param: "schedule" - profile schedule points.
2176 Param: <number> - step/bucket size as a power of 2 for
2177 statistical time based profiling.
2178 Param: "sleep" - profile D-state sleeping (millisecs).
2179 Requires CONFIG_SCHEDSTATS
2180 Param: "kvm" - profile VM exits.
2182 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2184 See Documentation/blockdev/ramdisk.txt.
2186 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2187 probe for; one of (bare|imps|exps|lifebook|any).
2188 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2190 psmouse.resetafter= [HW,MOUSE]
2191 Try to reset the device after so many bad packets
2194 [HW,MOUSE] Set desired mouse resolution, in dpi.
2195 psmouse.smartscroll=
2196 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2197 0 = disabled, 1 = enabled (default).
2199 pstore.backend= Specify the name of the pstore backend to use
2202 See Documentation/blockdev/paride.txt.
2205 [KNL] Number of legacy pty's. Overwrites compiled-in
2208 quiet [KNL] Disable most log messages
2213 See Documentation/md.txt.
2215 ramdisk_blocksize= [RAM]
2216 See Documentation/blockdev/ramdisk.txt.
2218 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2219 See Documentation/blockdev/ramdisk.txt.
2221 rcupdate.blimit= [KNL,BOOT]
2222 Set maximum number of finished RCU callbacks to process
2225 rcupdate.qhimark= [KNL,BOOT]
2226 Set threshold of queued
2227 RCU callbacks over which batch limiting is disabled.
2229 rcupdate.qlowmark= [KNL,BOOT]
2230 Set threshold of queued RCU callbacks below which
2231 batch limiting is re-enabled.
2235 Run specified binary instead of /init from the ramdisk,
2236 used for early userspace startup. See initrd.
2238 reassign_resources [PCI,ACPI,XEN]
2239 Use guestdev= parameter to reassign device's
2240 resources, or specify =all here.
2242 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2243 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2244 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2247 [KNL, SMP] Set scheduler's default relax_domain_level.
2248 See Documentation/cgroups/cpusets.txt.
2250 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2252 reservetop= [X86-32]
2254 Reserves a hole at the top of the kernel virtual
2259 Set the amount of memory to reserve for BIOS at
2260 the bottom of the address space.
2262 reset_devices [KNL] Force drivers to reset the underlying device
2263 during initialization.
2266 Specify the partition device for software suspend
2268 resume_offset= [SWSUSP]
2269 Specify the offset from the beginning of the partition
2270 given by "resume=" at which the swap header is located,
2271 in <PAGE_SIZE> units (needed only for swap files).
2272 See Documentation/power/swsusp-and-swap-files.txt
2274 hibernate= [HIBERNATION]
2275 noresume Don't check if there's a hibernation image
2276 present during boot.
2277 nocompress Don't compress/decompress hibernation images.
2279 retain_initrd [RAM] Keep initrd memory after extraction
2281 rhash_entries= [KNL,NET]
2282 Set number of hash buckets for route cache
2284 riscom8= [HW,SERIAL]
2285 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2287 ro [KNL] Mount root device read-only on boot
2289 root= [KNL] Root filesystem
2290 See name_to_dev_t comment in init/do_mounts.c.
2292 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2293 mount the root filesystem
2295 rootflags= [KNL] Set root filesystem mount option string
2297 rootfstype= [KNL] Set root filesystem type
2299 rootwait [KNL] Wait (indefinitely) for root device to show up.
2300 Useful for devices that are detected asynchronously
2301 (e.g. USB and MMC devices).
2303 rw [KNL] Mount root device read-write on boot
2305 S [KNL] Run init in single mode
2308 See drivers/net/irda/sa1100_ir.c.
2310 sbni= [NET] Granch SBNI12 leased line adapter
2312 sched_debug [KNL] Enables verbose scheduler debug messages.
2314 security= [SECURITY] Choose a security module to enable at boot.
2315 If this boot parameter is not specified, only the first
2316 security module asking for security registration will be
2317 loaded. An invalid security module name will be treated
2318 as if no module has been chosen.
2320 selinux= [SELINUX] Disable or enable SELinux at boot time.
2321 Format: { "0" | "1" }
2322 See security/selinux/Kconfig help text.
2325 Default value is set via kernel config option.
2326 If enabled at boot time, /selinux/disable can be used
2327 later to disable prior to initial policy load.
2329 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2330 Format: { "0" | "1" }
2331 See security/apparmor/Kconfig help text
2334 Default value is set via kernel config option.
2336 serialnumber [BUGS=X86-32]
2339 Maximal number of shapers.
2341 show_msr= [x86] show boot-time MSR settings
2342 Format: { <integer> }
2343 Show boot-time (BIOS-initialized) MSR settings.
2344 The parameter means the number of CPUs to show,
2345 for example 1 means boot CPU only.
2352 slub_debug[=options[,slabs]] [MM, SLUB]
2353 Enabling slub_debug allows one to determine the
2354 culprit if slab objects become corrupted. Enabling
2355 slub_debug can create guard zones around objects and
2356 may poison objects when not in use. Also tracks the
2357 last alloc / free. For more information see
2358 Documentation/vm/slub.txt.
2360 slub_max_order= [MM, SLUB]
2361 Determines the maximum allowed order for slabs.
2362 A high setting may cause OOMs due to memory
2363 fragmentation. For more information see
2364 Documentation/vm/slub.txt.
2366 slub_min_objects= [MM, SLUB]
2367 The minimum number of objects per slab. SLUB will
2368 increase the slab order up to slub_max_order to
2369 generate a sufficiently large slab able to contain
2370 the number of objects indicated. The higher the number
2371 of objects the smaller the overhead of tracking slabs
2372 and the less frequently locks need to be acquired.
2373 For more information see Documentation/vm/slub.txt.
2375 slub_min_order= [MM, SLUB]
2376 Determines the mininum page order for slabs. Must be
2377 lower than slub_max_order.
2378 For more information see Documentation/vm/slub.txt.
2380 slub_nomerge [MM, SLUB]
2381 Disable merging of slabs with similar size. May be
2382 necessary if there is some reason to distinguish
2383 allocs to different slabs. Debug options disable
2384 merging on their own.
2385 For more information see Documentation/vm/slub.txt.
2388 Format: <io1>[,<io2>[,...,<io8>]]
2390 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2391 attempt to substitute SMP alternatives once at boot.
2393 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2394 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2395 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2396 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2397 smsc-ircc2.ircc_irq= [HW] IRQ line
2398 smsc-ircc2.ircc_dma= [HW] DMA channel
2399 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2400 0: Toshiba Satellite 1800 (GP data pin select)
2401 1: Fast pin select (default)
2405 [KNL] Should the soft-lockup detector generate panics.
2408 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2409 See Documentation/sonypi.txt
2411 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2412 See Documentation/serial/specialix.txt.
2414 spia_io_base= [HW,MTD]
2420 Enabled the stack tracer on boot up.
2424 Set the STI (builtin display/keyboard on the HP-PARISC
2425 machines) console (graphic card) which should be used
2426 as the initial boot-console.
2427 See also comment in drivers/video/console/sticore.c.
2430 See comment in drivers/video/console/sticore.c.
2433 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2435 sunrpc.min_resvport=
2436 sunrpc.max_resvport=
2438 SunRPC servers often require that client requests
2439 originate from a privileged port (i.e. a port in the
2440 range 0 < portnr < 1024).
2441 An administrator who wishes to reserve some of these
2442 ports for other uses may adjust the range that the
2443 kernel's sunrpc client considers to be privileged
2444 using these two parameters to set the minimum and
2445 maximum port values.
2449 Control how the NFS server code allocates CPUs to
2450 service thread pools. Depending on how many NICs
2451 you have and where their interrupts are bound, this
2452 option will affect which CPUs will do NFS serving.
2453 Note: this parameter cannot be changed while the
2454 NFS server is running.
2456 auto the server chooses an appropriate mode
2457 automatically using heuristics
2458 global a single global pool contains all CPUs
2459 percpu one pool for each CPU
2460 pernode one pool for each NUMA node (equivalent
2461 to global on non-NUMA machines)
2463 sunrpc.tcp_slot_table_entries=
2464 sunrpc.udp_slot_table_entries=
2466 Sets the upper limit on the number of simultaneous
2467 RPC calls that can be sent from the client to a
2468 server. Increasing these values may allow you to
2469 improve throughput, but will also increase the
2470 amount of memory reserved for use by the client.
2473 [KNL] Enable accounting of swap in memory resource
2474 controller if no parameter or 1 is given or disable
2475 it if 0 is given (See Documentation/cgroups/memory.txt)
2477 swiotlb= [IA-64] Number of I/O TLB slabs
2481 sysfs.deprecated=0|1 [KNL]
2482 Enable/disable old style sysfs layout for old udev
2483 on older distributions. When this option is enabled
2484 very new udev will not work anymore. When this option
2485 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2486 in older udev will not work anymore.
2487 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2488 the kernel configuration.
2490 sysrq_always_enabled
2492 Ignore sysrq setting - this boot parameter will
2493 neutralize any effect of /proc/sys/kernel/sysrq.
2494 Useful for debugging.
2498 test_suspend= [SUSPEND]
2499 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2500 standby suspend) as the system sleep state to briefly
2501 enter during system startup. The system is woken from
2502 this state using a wakeup-capable RTC alarm.
2504 thash_entries= [KNL,NET]
2505 Set number of hash buckets for TCP connection
2507 thermal.act= [HW,ACPI]
2508 -1: disable all active trip points in all thermal zones
2509 <degrees C>: override all lowest active trip points
2511 thermal.crt= [HW,ACPI]
2512 -1: disable all critical trip points in all thermal zones
2513 <degrees C>: override all critical trip points
2515 thermal.nocrt= [HW,ACPI]
2516 Set to disable actions on ACPI thermal zone
2517 critical and hot trip points.
2519 thermal.off= [HW,ACPI]
2520 1: disable ACPI thermal control
2522 thermal.psv= [HW,ACPI]
2523 -1: disable all passive trip points
2524 <degrees C>: override all passive trip points to this
2527 thermal.tzp= [HW,ACPI]
2528 Specify global default ACPI thermal zone polling rate
2529 <deci-seconds>: poll all this frequency
2530 0: no polling (default)
2533 Force threading of all interrupt handlers except those
2534 marked explicitely IRQF_NO_THREAD.
2538 Specify if the kernel should make use of the cpu
2539 topology information if the hardware supports this.
2540 The scheduler will make use of this information and
2541 e.g. base its process migration decisions on it.
2546 tpm_suspend_pcr=[HW,TPM]
2547 Format: integer pcr id
2548 Specify that at suspend time, the tpm driver
2549 should extend the specified pcr with zeros,
2550 as a workaround for some chips which fail to
2551 flush the last written pcr on TPM_SaveState.
2552 This will guarantee that all the other pcrs
2555 trace_buf_size=nn[KMG]
2556 [FTRACE] will set tracing buffer size.
2558 trace_event=[event-list]
2559 [FTRACE] Set and start specified trace events in order
2560 to facilitate early boot debugging.
2561 See also Documentation/trace/events.txt
2563 tsc= Disable clocksource stability checks for TSC.
2565 [x86] reliable: mark tsc clocksource as reliable, this
2566 disables clocksource verification at runtime, as well
2567 as the stability checks done at bootup. Used to enable
2568 high-resolution timer mode on older hardware, and in
2569 virtualized environment.
2570 [x86] noirqtime: Do not use TSC to do irq accounting.
2571 Used to run time disable IRQ_TIME_ACCOUNTING on any
2572 platforms where RDTSC is slow and this accounting
2575 turbografx.map[2|3]= [HW,JOY]
2576 TurboGraFX parallel port interface
2578 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2579 See also Documentation/input/joystick-parport.txt
2581 udbg-immortal [PPC] When debugging early kernel crashes that
2582 happen after console_init() and before a proper
2583 console driver takes over, this boot options might
2584 help "seeing" what's going on.
2586 uhash_entries= [KNL,NET]
2587 Set number of hash buckets for UDP/UDP-Lite connections
2590 [USB] Ignore overcurrent events (default N).
2591 Some badly-designed motherboards generate lots of
2592 bogus events, for ports that aren't wired to
2593 anything. Set this parameter to avoid log spamming.
2594 Note that genuine overcurrent events won't be
2598 [X86] Cause panic on unknown NMI.
2600 unsupported Allow loading of unsupported kernel modules:
2601 0 = only allow supported modules,
2602 1 = warn when loading unsupported modules,
2605 CONFIG_ENTERPRISE_SUPPORT must be enabled for this
2608 usbcore.authorized_default=
2609 [USB] Default USB device authorization:
2610 (default -1 = authorized except for wireless USB,
2611 0 = not authorized, 1 = authorized)
2613 usbcore.autosuspend=
2614 [USB] The autosuspend time delay (in seconds) used
2615 for newly-detected USB devices (default 2). This
2616 is the time required before an idle device will be
2617 autosuspended. Devices for which the delay is set
2618 to a negative value won't be autosuspended at all.
2620 usbcore.usbfs_snoop=
2621 [USB] Set to log all usbfs traffic (default 0 = off).
2623 usbcore.blinkenlights=
2624 [USB] Set to cycle leds on hubs (default 0 = off).
2626 usbcore.old_scheme_first=
2627 [USB] Start with the old device initialization
2628 scheme (default 0 = off).
2630 usbcore.use_both_schemes=
2631 [USB] Try the other device initialization scheme
2632 if the first one fails (default 1 = enabled).
2634 usbcore.initial_descriptor_timeout=
2635 [USB] Specifies timeout for the initial 64-byte
2636 USB_REQ_GET_DESCRIPTOR request in milliseconds
2637 (default 5000 = 5.0 seconds).
2640 [USBHID] The interval which mice are to be polled at.
2642 usb-storage.delay_use=
2643 [UMS] The delay in seconds before a new device is
2644 scanned for Logical Units (default 5).
2647 [UMS] A list of quirks entries to supplement or
2648 override the built-in unusual_devs list. List
2649 entries are separated by commas. Each entry has
2650 the form VID:PID:Flags where VID and PID are Vendor
2651 and Product ID values (4-digit hex numbers) and
2652 Flags is a set of characters, each corresponding
2653 to a common usb-storage quirk flag as follows:
2654 a = SANE_SENSE (collect more than 18 bytes
2656 b = BAD_SENSE (don't collect more than 18
2657 bytes of sense data);
2658 c = FIX_CAPACITY (decrease the reported
2659 device capacity by one sector);
2660 d = NO_READ_DISC_INFO (don't use
2661 READ_DISC_INFO command);
2662 e = NO_READ_CAPACITY_16 (don't use
2663 READ_CAPACITY_16 command);
2664 h = CAPACITY_HEURISTICS (decrease the
2665 reported device capacity by one
2666 sector if the number is odd);
2667 i = IGNORE_DEVICE (don't bind to this
2669 l = NOT_LOCKABLE (don't try to lock and
2670 unlock ejectable media);
2671 m = MAX_SECTORS_64 (don't transfer more
2672 than 64 sectors = 32 KB at a time);
2673 n = INITIAL_READ10 (force a retry of the
2674 initial READ(10) command);
2675 o = CAPACITY_OK (accept the capacity
2676 reported by the device);
2677 r = IGNORE_RESIDUE (the device reports
2678 bogus residue values);
2679 s = SINGLE_LUN (the device has only one
2681 w = NO_WP_DETECT (don't test whether the
2682 medium is write-protected).
2683 Example: quirks=0419:aaf5:rl,0421:0433:rc
2685 user_debug= [KNL,ARM]
2687 See arch/arm/Kconfig.debug help text.
2688 1 - undefined instruction events
2690 4 - invalid data aborts
2693 Example: user_debug=31
2696 [X86] Flags controlling user PTE allocations.
2698 nohigh = do not allocate PTE pages in
2699 HIGHMEM regardless of setting
2703 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2704 vdso=1: enable VDSO (default)
2705 vdso=0: disable VDSO mapping
2708 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2709 vdso32=1: enable 32-bit VDSO (default)
2710 vdso32=0: disable 32-bit VDSO mapping
2713 vector=percpu: enable percpu vector domain
2715 video= [FB] Frame buffer configuration
2716 See Documentation/fb/modedb.txt.
2718 vga= [BOOT,X86-32] Select a particular video mode
2719 See Documentation/x86/boot.txt and
2720 Documentation/svga.txt.
2721 Use vga=ask for menu.
2722 This is actually a boot loader parameter; the value is
2723 passed to the kernel using a special protocol.
2725 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2726 size of <nn>. This can be used to increase the
2727 minimum size (128MB on x86). It can also be used to
2728 decrease the size and leave more room for directly
2731 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2734 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2737 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2741 Controls the behavior of vsyscalls (i.e. calls to
2742 fixed addresses of 0xffffffffff600x00 from legacy
2743 code). Most statically-linked binaries and older
2744 versions of glibc use these calls. Because these
2745 functions are at fixed addresses, they make nice
2746 targets for exploits that can control RIP.
2748 emulate Vsyscalls turn into traps and are emulated
2751 native [default] Vsyscalls are native syscall
2753 This is a little bit faster than trapping
2754 and makes a few dynamic recompilers work
2755 better than they would in emulation mode.
2756 It also makes exploits much easier to write.
2758 none Vsyscalls don't work at all. This makes
2759 them quite hard to use for exploits but
2760 might break your system.
2762 vt.cur_default= [VT] Default cursor shape.
2763 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2764 the parameters of the <Esc>[?A;B;Cc escape sequence;
2765 see VGA-softcursor.txt. Default: 2 = underline.
2767 vt.default_blu= [VT]
2768 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2769 Change the default blue palette of the console.
2770 This is a 16-member array composed of values
2773 vt.default_grn= [VT]
2774 Format: <green0>,<green1>,<green2>,...,<green15>
2775 Change the default green palette of the console.
2776 This is a 16-member array composed of values
2779 vt.default_red= [VT]
2780 Format: <red0>,<red1>,<red2>,...,<red15>
2781 Change the default red palette of the console.
2782 This is a 16-member array composed of values
2788 Set system-wide default UTF-8 mode for all tty's.
2789 Default is 1, i.e. UTF-8 mode is enabled for all
2790 newly opened terminals.
2792 vt.global_cursor_default=
2795 Set system-wide default for whether a cursor
2796 is shown on new VTs. Default is -1,
2797 i.e. cursors will be created by default unless
2798 overridden by individual drivers. 0 will hide
2799 cursors, 1 will display them.
2801 watchdog timers [HW,WDT] For information on watchdog timers,
2802 see Documentation/watchdog/watchdog-parameters.txt
2803 or other driver-specific files in the
2804 Documentation/watchdog/ directory.
2806 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2807 default x2apic cluster mode on platforms
2810 x86_mrst_timer= [X86-32,APBT]
2811 Choose timer option for x86 Moorestown MID platform.
2812 Two valid options are apbt timer only and lapic timer
2813 plus one apbt timer for broadcast timer.
2814 x86_mrst_timer=apbt_only | lapic_and_apbt
2816 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2817 xd_geo= See header of drivers/block/xd.c.
2819 xen_emul_unplug= [HW,X86,XEN]
2820 Unplug Xen emulated devices
2821 Format: [unplug0,][unplug1]
2822 ide-disks -- unplug primary master IDE devices
2823 aux-ide-disks -- unplug non-primary-master IDE devices
2824 nics -- unplug network devices
2825 all -- unplug all emulated devices (NICs and IDE disks)
2826 unnecessary -- unplugging emulated devices is
2827 unnecessary even if the host did not respond to
2829 never -- do not unplug even if version check succeeds
2831 xirc2ps_cs= [NET,PCMCIA]
2833 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2835 ______________________________________________________________________
2839 Add more DRM drivers.
projects / linux-flexiantxendom0-3.2.10.git / blob