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 EVM Extended Verification Module
53 FB The frame buffer device is enabled.
54 FTRACE Function tracing enabled.
55 GCOV GCOV profiling is enabled.
56 HW Appropriate hardware is enabled.
57 IA-64 IA-64 architecture is enabled.
58 IMA Integrity measurement architecture is enabled.
59 IOSCHED More than one I/O scheduler is enabled.
60 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
61 IPV6 IPv6 support is enabled.
62 ISAPNP ISA PnP code is enabled.
63 ISDN Appropriate ISDN support is enabled.
64 JOY Appropriate joystick support is enabled.
65 KGDB Kernel debugger support is enabled.
66 KVM Kernel Virtual Machine support is enabled.
67 LIBATA Libata driver is enabled
68 LP Printer support is enabled.
69 LOOP Loopback device support is enabled.
70 M68k M68k architecture is enabled.
71 These options have more detailed description inside of
72 Documentation/m68k/kernel-options.txt.
73 MCA MCA bus support is enabled.
74 MDA MDA console support is enabled.
75 MIPS MIPS architecture is enabled.
76 MOUSE Appropriate mouse support is enabled.
77 MSI Message Signaled Interrupts (PCI).
78 MTD MTD (Memory Technology Device) support is enabled.
79 NET Appropriate network support is enabled.
80 NUMA NUMA support is enabled.
81 NFS Appropriate NFS support is enabled.
82 OSS OSS sound support is enabled.
83 PV_OPS A paravirtualized kernel is enabled.
84 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
85 PARISC The PA-RISC architecture is enabled.
86 PCI PCI bus support is enabled.
87 PCIE PCI Express support is enabled.
88 PCMCIA The PCMCIA subsystem is enabled.
89 PNP Plug & Play support is enabled.
90 PPC PowerPC architecture is enabled.
91 PPT Parallel port support is enabled.
92 PS2 Appropriate PS/2 support is enabled.
93 RAM RAM disk support is enabled.
94 S390 S390 architecture is enabled.
95 SCSI Appropriate SCSI support is enabled.
96 A lot of drivers have their options described inside
97 the Documentation/scsi/ sub-directory.
98 SECURITY Different security models are enabled.
99 SELINUX SELinux support is enabled.
100 APPARMOR AppArmor support is enabled.
101 SERIAL Serial support is enabled.
102 SH SuperH architecture is enabled.
103 SMP The kernel is an SMP kernel.
104 SPARC Sparc architecture is enabled.
105 SWSUSP Software suspend (hibernation) is enabled.
106 SUSPEND System suspend states are enabled.
107 TPM TPM drivers are enabled.
108 TS Appropriate touchscreen support is enabled.
109 UMS USB Mass Storage support is enabled.
110 USB USB support is enabled.
111 USBHID USB Human Interface Device support is enabled.
112 V4L Video For Linux support is enabled.
113 VGA The VGA console has been enabled.
114 VT Virtual terminal support is enabled.
115 WDT Watchdog support is enabled.
116 XT IBM PC/XT MFM hard disk support is enabled.
117 X86-32 X86-32, aka i386 architecture is enabled.
118 X86-64 X86-64 architecture is enabled.
119 More X86-64 boot options can be found in
120 Documentation/x86/x86_64/boot-options.txt .
121 X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
122 XEN Xen support is enabled
124 In addition, the following text indicates that the option:
126 BUGS= Relates to possible processor bugs on the said processor.
127 KNL Is a kernel start-up parameter.
128 BOOT Is a boot loader parameter.
130 Parameters denoted with BOOT are actually interpreted by the boot
131 loader, and have no meaning to the kernel directly.
132 Do not modify the syntax of boot loader parameters without extreme
133 need or coordination with <Documentation/x86/boot.txt>.
135 There are also arch-specific kernel-parameters not documented here.
136 See for example <Documentation/x86/x86_64/boot-options.txt>.
138 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
139 a trailing = on the name of any parameter states that that parameter will
140 be entered as an environment variable, whereas its absence indicates that
141 it will appear as a kernel argument readable via /proc/cmdline by programs
142 running once the system is up.
144 The number of kernel parameters is not limited, but the length of the
145 complete command line (parameters including spaces etc.) is limited to
146 a fixed number of characters. This limit depends on the architecture
147 and is between 256 and 4096 characters. It is defined in the file
148 ./include/asm/setup.h as COMMAND_LINE_SIZE.
150 Finally, the [KMG] suffix is commonly described after a number of kernel
151 parameter values. These 'K', 'M', and 'G' letters represent the _binary_
152 multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
153 bytes respectively. Such letter suffixes can also be entirely omitted.
157 Advanced Configuration and Power Interface
158 Format: { force | off | strict | noirq | rsdt }
159 force -- enable ACPI if default was off
160 off -- disable ACPI if default was on
161 noirq -- do not use ACPI for IRQ routing
162 strict -- Be less tolerant of platforms that are not
163 strictly ACPI specification compliant.
164 rsdt -- prefer RSDT over (default) XSDT
165 copy_dsdt -- copy DSDT to memory
167 See also Documentation/power/runtime_pm.txt, pci=noacpi
169 acpi_rsdp= [ACPI,EFI,KEXEC]
170 Pass the RSDP address to the kernel, mostly used
171 on machines running EFI runtime service to boot the
172 second kernel for kdump.
174 acpi_apic_instance= [ACPI, IOAPIC]
176 2: use 2nd APIC table, if available
177 1,0: use 1st APIC table
180 acpi_backlight= [HW,ACPI]
181 acpi_backlight=vendor
183 If set to vendor, prefer vendor specific driver
184 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
185 of the ACPI video.ko driver.
187 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
188 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
190 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
191 debug output. Bits in debug_layer correspond to a
192 _COMPONENT in an ACPI source file, e.g.,
193 #define _COMPONENT ACPI_PCI_COMPONENT
194 Bits in debug_level correspond to a level in
195 ACPI_DEBUG_PRINT statements, e.g.,
196 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
197 The debug_level mask defaults to "info". See
198 Documentation/acpi/debug.txt for more information about
199 debug layers and levels.
201 Enable processor driver info messages:
202 acpi.debug_layer=0x20000000
203 Enable PCI/PCI interrupt routing info messages:
204 acpi.debug_layer=0x400000
205 Enable AML "Debug" output, i.e., stores to the Debug
206 object while interpreting AML:
207 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
208 Enable all messages related to ACPI hardware:
209 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
211 Some values produce so much output that the system is
212 unusable. The "log_buf_len" parameter may be useful
213 if you need to capture more output.
215 acpi_irq_balance [HW,ACPI]
216 ACPI will balance active IRQs
219 acpi_irq_nobalance [HW,ACPI]
220 ACPI will not move active IRQs (default)
223 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
224 Format: <irq>,<irq>...
226 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
228 Format: <irq>,<irq>...
230 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
232 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
233 Format: To spoof as Windows 98: ="Microsoft Windows"
235 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
236 acpi_osi="string1" # add string1 -- only one string
237 acpi_osi="!string2" # remove built-in string2
238 acpi_osi= # disable all strings
241 Override the pmtimer bug detection: force the kernel
242 to assume that this machine's pmtimer latches its value
243 and always returns good values.
245 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
246 Format: { level | edge | high | low }
248 acpi_serialize [HW,ACPI] force serialization of AML methods
250 acpi_skip_timer_override [HW,ACPI]
251 Recognize and ignore IRQ0/pin2 Interrupt Override.
252 For broken nForce2 BIOS resulting in XT-PIC timer.
254 acpi_sleep= [HW,ACPI] Sleep options
255 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
256 old_ordering, nonvs, sci_force_enable }
257 See Documentation/power/video.txt for information on
259 s3_beep is for debugging; it makes the PC's speaker beep
260 as soon as the kernel's real-mode entry point is called.
261 s4_nohwsig prevents ACPI hardware signature from being
262 used during resume from hibernation.
263 old_ordering causes the ACPI 1.0 ordering of the _PTS
264 control method, with respect to putting devices into
265 low power states, to be enforced (the ACPI 2.0 ordering
266 of _PTS is used by default).
267 nonvs prevents the kernel from saving/restoring the
268 ACPI NVS memory during suspend/hibernation and resume.
269 sci_force_enable causes the kernel to set SCI_EN directly
270 on resume from S1/S3 (which is against the ACPI spec,
271 but some broken systems don't work without it).
273 acpi_use_timer_override [HW,ACPI]
274 Use timer override. For some broken Nvidia NF5 boards
275 that require a timer override, but don't have HPET
277 acpi_enforce_resources= [ACPI]
278 { strict | lax | no }
279 Check for resource conflicts between native drivers
280 and ACPI OperationRegions (SystemIO and SystemMemory
281 only). IO ports and memory declared in ACPI might be
282 used by the ACPI subsystem in arbitrary AML code and
283 can interfere with legacy drivers.
284 strict (default): access to resources claimed by ACPI
285 is denied; legacy drivers trying to access reserved
286 resources will fail to bind to device using them.
287 lax: access to resources claimed by ACPI is allowed;
288 legacy drivers trying to access reserved resources
289 will bind successfully but a warning message is logged.
290 no: ACPI OperationRegions are not marked as reserved,
291 no further checks are performed.
293 add_efi_memmap [EFI; X86] Include EFI memory map in
294 kernel's map of available physical RAM.
297 { off | try_unsupported }
298 off: disable AGP support
299 try_unsupported: try to drive unsupported chipsets
300 (may crash computer or cause data corruption)
303 See Documentation/sound/alsa/alsa-parameters.txt
306 Allow the default userspace alignment fault handler
307 behaviour to be specified. Bit 0 enables warnings,
308 bit 1 enables fixups, and bit 2 sends a segfault.
310 align_va_addr= [X86-64]
311 Align virtual addresses by clearing slice [14:12] when
312 allocating a VMA at process creation time. This option
313 gives you up to 3% performance improvement on AMD F15h
314 machines (where it is enabled by default) for a
315 CPU-intensive style benchmark, and it can vary highly in
316 a microbenchmark depending on workload and compiler.
318 32: only for 32-bit processes
319 64: only for 64-bit processes
320 on: enable for both 32- and 64-bit processes
321 off: disable for both 32- and 64-bit processes
323 amd_iommu= [HW,X86-64]
324 Pass parameters to the AMD IOMMU driver in the system.
326 fullflush - enable flushing of IO/TLB entries when
327 they are unmapped. Otherwise they are
328 flushed before they will be reused, which
330 off - do not initialize any AMD IOMMU found in
333 amijoy.map= [HW,JOY] Amiga joystick support
334 Map of devices attached to JOY0DAT and JOY1DAT
336 See also Documentation/input/joystick.txt
338 analog.map= [HW,JOY] Analog joystick and gamepad support
339 Specifies type or capabilities of an analog joystick
340 connected to one of 16 gameports
341 Format: <type1>,<type2>,..<type16>
344 Power management functions (SPARCstation-4/5 + deriv.)
346 Disable APC CPU standby support. SPARCstation-Fox does
347 not play well with APC CPU idle - disable it if you have
348 APC and your system crashes randomly.
350 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
351 Change the output verbosity whilst booting
352 Format: { quiet (default) | verbose | debug }
353 Change the amount of debugging information output
354 when initialising the APIC and IO-APIC components.
357 See Documentation/networking/ipv6.txt.
359 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
360 Limit apic dumping. The parameter defines the maximal
361 number of local apics being dumped. Also it is possible
362 to set it to "all" by meaning -- no limit here.
363 Format: { 1 (default) | 2 | ... | all }.
364 The parameter valid if only apic=debug or
365 apic=verbose is specified.
366 Example: apic=debug show_lapic=all
368 apm= [APM] Advanced Power Management
369 See header of arch/x86/kernel/apm_32.c.
371 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
372 Format: <io>,<irq>,<nodeID>
376 atarimouse= [HW,MOUSE] Atari Mouse
378 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
379 EzKey and similar keyboards
381 atkbd.reset= [HW] Reset keyboard during initialization
383 atkbd.set= [HW] Select keyboard code set
384 Format: <int> (2 = AT (default), 3 = PS/2)
386 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
389 atkbd.softraw= [HW] Choose between synthetic and real raw mode
390 Format: <bool> (0 = real, 1 = synthetic (default))
392 atkbd.softrepeat= [HW]
393 Use software keyboard repeat
397 baycom_epp= [HW,AX25]
400 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
402 See header of drivers/net/hamradio/baycom_par.c.
404 baycom_ser_fdx= [HW,AX25]
405 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
406 Format: <io>,<irq>,<mode>[,<baud>]
407 See header of drivers/net/hamradio/baycom_ser_fdx.c.
409 baycom_ser_hdx= [HW,AX25]
410 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
411 Format: <io>,<irq>,<mode>
412 See header of drivers/net/hamradio/baycom_ser_hdx.c.
414 boot_delay= Milliseconds to delay each printk during boot.
415 Values larger than 10 seconds (10000) are changed to
419 bootmem_debug [KNL] Enable bootmem allocator debug messages.
421 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
422 bttv.radio= Most important insmod options are available as
424 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
427 bulk_remove=off [PPC] This parameter disables the use of the pSeries
428 firmware feature for flushing multiple hpte entries
431 c101= [NET] Moxa C101 synchronous serial card
433 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
434 Sometimes CPU hardware bugs make them report the cache
435 size incorrectly. The kernel will attempt work arounds
436 to fix known problems, but for some CPUs it is not
437 possible to determine what the correct size should be.
438 This option provides an override for these situations.
441 [SECURITY] Disable capabilities. This would normally
442 be used only if an alternative security model is to be
443 configured. Potentially dangerous and should only be
444 used if you are entirely sure of the consequences.
446 ccw_timeout_log [S390]
447 See Documentation/s390/CommonIO for details.
449 cgroup_disable= [KNL] Disable a particular controller
450 Format: {name of the controller(s) to disable}
451 {Currently supported controllers - "memory"}
453 checkreqprot [SELINUX] Set initial checkreqprot flag value.
454 Format: { "0" | "1" }
455 See security/selinux/Kconfig help text.
456 0 -- check protection applied by kernel (includes
457 any implied execute protection).
458 1 -- check protection requested by application.
459 Default value is set via a kernel config option.
460 Value can be changed at runtime via
461 /selinux/checkreqprot.
464 See Documentation/s390/CommonIO for details.
466 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
468 Forces specified clocksource (if available) to be used
469 when calculating gettimeofday(). If specified
470 clocksource is not available, it defaults to PIT.
471 Format: { pit | tsc | cyclone | pmtmr }
473 clocksource= Override the default clocksource
475 Override the default clocksource and use the clocksource
476 with the name specified.
477 Some clocksource names to choose from, depending on
479 [all] jiffies (this is the base, fallback clocksource)
481 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
482 pxa_timer,timer3,32k_counter,timer0_1
484 [X86-32] pit,hpet,tsc;
485 scx200_hrt on Geode; cyclone on IBM x440
493 clearcpuid=BITNUM [X86]
494 Disable CPUID feature X for the kernel. See
495 arch/x86/include/asm/cpufeature.h for the valid bit
496 numbers. Note the Linux specific bits are not necessarily
497 stable over kernel options, but the vendor specific
499 Also note that user programs calling CPUID directly
500 or using the feature without checking anything
501 will still see it. This just prevents it from
502 being used by the kernel or shown in /proc/cpuinfo.
503 Also note the kernel might malfunction if you disable
507 Sets the size of kernel global memory area for contiguous
508 memory allocations. For more information, see
509 include/linux/dma-contiguous.h
511 cmo_free_hint= [PPC] Format: { yes | no }
512 Specify whether pages are marked as being inactive
513 when they are freed. This is used in CMO environments
514 to determine OS memory pressure for page stealing by
518 code_bytes [X86] How many bytes of object code to print
523 com20020= [HW,NET] ARCnet - COM20020 chipset
525 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
527 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
531 ARCnet - COM90xx chipset (memory-mapped buffers)
532 Format: <io>[,<irq>[,<memstart>]]
534 condev= [HW,S390] console device
537 console= [KNL] Output console device and options.
539 tty<n> Use the virtual console device <n>.
543 Use the specified serial port. The options are of
544 the form "bbbbpnf", where "bbbb" is the baud rate,
545 "p" is parity ("n", "o", or "e"), "n" is number of
546 bits, and "f" is flow control ("r" for RTS or
547 omit it). Default is "9600n8".
549 See Documentation/serial-console.txt for more
551 Documentation/networking/netconsole.txt for an
554 uart[8250],io,<addr>[,options]
555 uart[8250],mmio,<addr>[,options]
556 Start an early, polled-mode console on the 8250/16550
557 UART at the specified I/O port or MMIO address,
558 switching to the matching ttyS device later. The
559 options are the same as for ttyS, above.
561 If the device connected to the port is not a TTY but a braille
562 device, prepend "brl," before the device type, for instance
564 For now, only VisioBraille is supported.
566 consoleblank= [KNL] The console blank (screen saver) timeout in
567 seconds. Defaults to 10*60 = 10mins. A value of 0
568 disables the blank timer.
571 [KNL] Change the default value for
572 /proc/<pid>/coredump_filter.
573 See also Documentation/filesystems/proc.txt.
575 cpuidle.off=1 [CPU_IDLE]
576 disable the cpuidle sub-system
578 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
580 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
582 crashkernel=size[KMG][@offset[KMG]]
583 [KNL] Using kexec, Linux can switch to a 'crash kernel'
584 upon panic. This parameter reserves the physical
585 memory region [offset, offset + size] for that kernel
586 image. If '@offset' is omitted, then a suitable offset
587 is selected automatically. Check
588 Documentation/kdump/kdump.txt for further details.
590 crashkernel=range1:size1[,range2:size2,...][@offset]
591 [KNL] Same as above, but depends on the memory
592 in the running system. The syntax of range is
593 start-[end] where start and end are both
594 a memory unit (amount[KMG]). See also
595 Documentation/kdump/kdump.txt for an example.
600 cs89x0_media= [HW,NET]
601 Format: { rj45 | aui | bnc }
604 See header of drivers/s390/block/dasd_devmap.c.
606 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
607 (one device per port)
608 Format: <port#>,<type>
609 See also Documentation/input/joystick-parport.txt
611 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
612 time. See Documentation/dynamic-debug-howto.txt for
615 debug [KNL] Enable kernel debugging (events log level).
618 [KNL] verbose self-tests
620 Print debugging info while doing the locking API
622 We default to 0 (no extra messages), setting it to
623 1 will print _a lot_ more information - normally
624 only useful to kernel developers.
626 debug_objects [KNL] Enable object debugging
629 [KNL] Disable object debugging
631 debug_guardpage_minorder=
632 [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
633 parameter allows control of the order of pages that will
634 be intentionally kept free (and hence protected) by the
635 buddy allocator. Bigger value increase the probability
636 of catching random memory corruption, but reduce the
637 amount of memory for normal system use. The maximum
638 possible value is MAX_ORDER/2. Setting this parameter
639 to 1 or 2 should be enough to identify most random
640 memory corruption problems caused by bugs in kernel or
641 driver code when a CPU writes to (or reads from) a
642 random memory location. Note that there exists a class
643 of memory corruptions problems caused by buggy H/W or
644 F/W or by drivers badly programing DMA (basically when
645 memory is written at bus level and the CPU MMU is
646 bypassed) which are not detectable by
647 CONFIG_DEBUG_PAGEALLOC, hence this option will not help
648 tracking down these problems.
650 debugpat [X86] Enable PAT debugging
652 decnet.addr= [HW,NET]
653 Format: <area>[,<node>]
654 See also Documentation/networking/decnet.txt.
657 [same as hugepagesz=] The size of the default
658 HugeTLB page size. This is the size represented by
659 the legacy /proc/ hugepages APIs, used for SHM, and
660 default size when mounting hugetlbfs filesystems.
661 Defaults to the default architecture's huge page size
665 Set number of hash buckets for dentry cache.
668 IO parameters + enable/disable command.
670 digiepca= [HW,SERIAL]
671 See drivers/char/README.epca and
672 Documentation/serial/digiepca.txt.
675 See Documentation/networking/ipv6.txt.
677 disable_ddw [PPC/PSERIES]
678 Disable Dynamic DMA Window support. Use this if
679 to workaround buggy firmware.
682 See Documentation/networking/ipv6.txt.
684 disable_mtrr_cleanup [X86]
685 The kernel tries to adjust MTRR layout from continuous
686 to discrete, to make X server driver able to add WB
687 entry later. This parameter disables that.
689 disable_mtrr_trim [X86, Intel and AMD only]
690 By default the kernel will trim any uncacheable
691 memory out of your available memory pool based on
692 MTRR settings. This parameter disables that behavior,
693 possibly causing your machine to run very slowly.
695 disable_timer_pin_1 [X86]
696 Disable PIN 1 of APIC timer
697 Can be useful to work around chipset bugs.
699 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
700 this option disables the debugging code at boot.
702 dma_debug_entries=<number>
703 This option allows to tune the number of preallocated
704 entries for DMA-API debugging code. One entry is
705 required per DMA-API allocation. Use this if the
706 DMA-API debugging code disables itself because the
707 architectural default is too low.
709 dma_debug_driver=<driver_name>
710 With this option the DMA-API debugging driver
711 filter feature can be enabled at boot time. Just
712 pass the driver to filter for as the parameter.
713 The filter can be disabled or changed to another
714 driver later using sysfs.
718 earlycon= [KNL] Output early console device and options.
719 uart[8250],io,<addr>[,options]
720 uart[8250],mmio,<addr>[,options]
721 uart[8250],mmio32,<addr>[,options]
722 Start an early, polled-mode console on the 8250/16550
723 UART at the specified I/O port or MMIO address.
724 MMIO inter-register address stride is either 8-bit
725 (mmio) or 32-bit (mmio32).
726 The options are the same as for ttyS, above.
728 earlyprintk= [X86,SH,BLACKFIN]
730 earlyprintk=serial[,ttySn[,baudrate]]
731 earlyprintk=ttySn[,baudrate]
732 earlyprintk=dbgp[debugController#]
734 Append ",keep" to not disable it when the real console
737 Only vga or serial or usb debug port at a time.
739 Currently only ttyS0 and ttyS1 are supported.
741 Interaction with the standard serial driver is not
744 The VGA output is eventually overwritten by the real
747 ekgdboc= [X86,KGDB] Allow early kernel console debugging
750 This is designed to be used in conjunction with
751 the boot argument: earlyprintk=vga
754 Format: {"off" | "on" | "skip[mbr]"}
756 eisa_irq_edge= [PARISC,HW]
757 See header of drivers/parisc/eisa.c.
760 See comment before function elanfreq_setup() in
761 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
764 Format: {"cfq" | "deadline" | "noop"}
765 See Documentation/block/cfq-iosched.txt and
766 Documentation/block/deadline-iosched.txt for details.
768 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
769 Specifies physical address of start of kernel core
770 image elf header and optionally the size. Generally
771 kexec loader will pass this option to capture kernel.
772 See Documentation/kdump/kdump.txt for details.
774 enable_mtrr_cleanup [X86]
775 The kernel tries to adjust MTRR layout from continuous
776 to discrete, to make X server driver able to add WB
777 entry later. This parameter enables that.
779 enable_timer_pin_1 [X86]
780 Enable PIN 1 of APIC timer
781 Can be useful to work around chipset bugs
782 (in particular on some ATI chipsets).
783 The kernel tries to set a reasonable default.
785 enforcing [SELINUX] Set initial enforcing status.
787 See security/selinux/Kconfig help text.
788 0 -- permissive (log only, no denials).
789 1 -- enforcing (deny and log).
791 Value can be changed at runtime via /selinux/enforce.
794 Disable Error Record Serialization Table (ERST)
797 ether= [HW,NET] Ethernet cards parameters
798 This option is obsoleted by the "netdev=" option, which
799 has equivalent usage. See its documentation for details.
803 Permit 'security.evm' to be updated regardless of
804 current integrity status.
808 fail_make_request=[KNL]
809 General fault injection mechanism.
810 Format: <interval>,<probability>,<space>,<times>
811 See also Documentation/fault-injection/.
814 See Documentation/blockdev/floppy.txt.
816 force_pal_cache_flush
817 [IA-64] Avoid check_sal_cache_flush which may hang on
818 buggy SAL_CACHE_FLUSH implementations. Using this
819 parameter will force ia64_sal_cache_flush to call
820 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
823 [FTRACE] will set and start the specified tracer
824 as early as possible in order to facilitate early
827 ftrace_dump_on_oops[=orig_cpu]
828 [FTRACE] will dump the trace buffers on oops.
829 If no parameter is passed, ftrace will dump
830 buffers of all CPUs, but if you pass orig_cpu, it will
831 dump only the buffer of the CPU that triggered the
834 ftrace_filter=[function-list]
835 [FTRACE] Limit the functions traced by the function
836 tracer at boot up. function-list is a comma separated
837 list of functions. This list can be changed at run
838 time by the set_ftrace_filter file in the debugfs
841 ftrace_notrace=[function-list]
842 [FTRACE] Do not trace the functions specified in
843 function-list. This list can be changed at run time
844 by the set_ftrace_notrace file in the debugfs
847 ftrace_graph_filter=[function-list]
848 [FTRACE] Limit the top level callers functions traced
849 by the function graph tracer at boot up.
850 function-list is a comma separated list of functions
851 that can be changed at run time by the
852 set_graph_function file in the debugfs tracing directory.
855 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
856 support via parallel port (up to 5 devices per port)
857 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
858 See also Documentation/input/joystick-parport.txt
862 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
866 gcov_persist= [GCOV] When non-zero (default), profiling data for
867 kernel modules is saved and remains accessible via
868 debugfs, even when the module is unloaded/reloaded.
869 When zero, profiling data is discarded and associated
870 debugfs files are removed at module unload time.
872 gpt [EFI] Forces disk with valid GPT signature but
873 invalid Protective MBR to be treated as GPT.
875 hashdist= [KNL,NUMA] Large hashes allocated during boot
876 are distributed across NUMA nodes. Defaults on
877 for 64-bit NUMA, off otherwise.
878 Format: 0 | 1 (for off | on)
880 hcl= [IA-64] SGI's Hardware Graph compatibility layer
882 hd= [EIDE] (E)IDE hard drive subsystem geometry
883 Format: <cyl>,<head>,<sect>
886 Disable Hardware Error Source Table (HEST) support;
887 corresponding firmware-first mode error processing
888 logic will be disabled.
890 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
891 size of <nn>. This works even on boxes that have no
892 highmem otherwise. This also works to reduce highmem
893 size on bigger boxes.
895 highres= [KNL] Enable/disable high resolution timer mode.
896 Valid parameters: "on", "off"
900 See Documentation/isdn/README.HiSax.
904 hpet= [X86-32,HPET] option to control HPET usage
905 Format: { enable (default) | disable | force |
907 disable: disable HPET and use PIT instead
908 force: allow force enabled of undocumented chips (ICH4,
910 verbose: show contents of HPET registers during setup
912 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
913 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
914 On x86-64 and powerpc, this option can be specified
915 multiple times interleaved with hugepages= to reserve
916 huge pages of different sizes. Valid pages sizes on
917 x86-64 are 2M (when the CPU supports "pse") and 1G
918 (when the CPU supports the "pdpe1gb" cpuinfo flag)
919 Note that 1GB pages can only be allocated at boot time
920 using hugepages= and not freed afterwards.
922 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
923 terminal devices. Valid values: 0..8
924 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
925 If specified, z/VM IUCV HVC accepts connections
926 from listed z/VM user IDs only.
929 Do not unregister boot console at start. This is only
930 useful for debugging when something happens in the window
931 between unregistering the boot console and initializing
934 i2c_bus= [HW] Override the default board specific I2C bus speed
935 or register an additional I2C bus that is not
936 registered from board initialization code.
940 i8042.debug [HW] Toggle i8042 debug mode
941 i8042.direct [HW] Put keyboard port into non-translated mode
942 i8042.dumbkbd [HW] Pretend that controller can only read data from
943 keyboard and cannot control its state
944 (Don't attempt to blink the leds)
945 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
946 i8042.nokbd [HW] Don't check/create keyboard port
947 i8042.noloop [HW] Disable the AUX Loopback command while probing
949 i8042.nomux [HW] Don't check presence of an active multiplexing
951 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
953 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
954 i8042.reset [HW] Reset the controller during init and cleanup
955 i8042.unlock [HW] Unlock (ignore) the keylock
959 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
960 indicates that the driver is running on unsupported
962 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
963 does not match list of supported models.
965 [HW] Report power status in /proc/i8k
966 (disabled by default)
967 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
971 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
973 ide-core.nodma= [HW] (E)IDE subsystem
974 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
975 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
976 .cdrom .chs .ignore_cable are additional options
977 See Documentation/ide/ide.txt.
979 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
980 Claim all unknown PCI IDE storage controllers.
983 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
984 Poll forces a polling idle loop that can slightly
985 improve the performance of waking up a idle CPU, but
986 will use a lot of power and make the system run hot.
988 idle=mwait: On systems which support MONITOR/MWAIT but
989 the kernel chose to not use it because it doesn't save
990 as much power as a normal idle loop, use the
991 MONITOR/MWAIT idle loop anyways. Performance should be
992 the same as idle=poll.
993 idle=halt: Halt is forced to be used for CPU idle.
994 In such case C2/C3 won't be used again.
995 idle=nomwait: Disable mwait for CPU C-states
997 ignore_loglevel [KNL]
998 Ignore loglevel setting - this will print /all/
999 kernel messages to the console. Useful for debugging.
1000 We also add it as printk module parameter, so users
1001 could change it dynamically, usually by
1002 /sys/module/printk/parameters/ignore_loglevel.
1004 ihash_entries= [KNL]
1005 Set number of hash buckets for inode cache.
1008 Format: { "0" | "1" }
1009 0 -- integrity auditing messages. (Default)
1010 1 -- enable informational integrity auditing messages.
1013 Format: { "sha1" | "md5" }
1017 Load a policy which meets the needs of the Trusted
1018 Computing Base. This means IMA will measure all
1019 programs exec'd, files mmap'd for exec, and all files
1020 opened for read by uid=0.
1024 Run specified binary instead of /sbin/init as init
1027 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1028 for working out where the kernel is dying during
1031 initrd= [BOOT] Specify the location of the initial ramdisk
1033 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1036 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1038 Enable intel iommu driver.
1040 Disable intel iommu driver.
1041 igfx_off [Default Off]
1042 By default, gfx is mapped as normal device. If a gfx
1043 device has a dedicated DMAR unit, the DMAR unit is
1044 bypassed by not enabling DMAR with this option. In
1045 this case, gfx device will use physical address for
1048 With this option iommu will not optimize to look
1049 for io virtual address below 32-bit forcing dual
1050 address cycle on pci bus for cards supporting greater
1051 than 32-bit addressing. The default is to look
1052 for translation below 32-bit and if not available
1053 then look in the higher range.
1054 strict [Default Off]
1055 With this option on every unmap_single operation will
1056 result in a hardware IOTLB flush operation as opposed
1057 to batching them for performance.
1058 sp_off [Default Off]
1059 By default, super page will be supported if Intel IOMMU
1060 has the capability. With this option, super page will
1062 intremap= [X86-64, Intel-IOMMU]
1063 on enable Interrupt Remapping (default)
1064 off disable Interrupt Remapping
1065 nosid disable Source ID checking
1067 BIOS x2APIC opt-out request will be ignored
1071 iomem= Disable strict checking of access to MMIO memory
1072 strict regions from userspace.
1088 io7= [HW] IO7 for Marvel based alpha systems
1089 See comment before marvel_specify_io7 in
1090 arch/alpha/kernel/core_marvel.c.
1092 io_delay= [X86] I/O delay method
1094 Standard port 0x80 based delay
1096 Alternate port 0xed based delay (needed on some systems)
1098 Simple two microseconds delay
1103 See Documentation/filesystems/nfs/nfsroot.txt.
1105 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1106 See comment before ip2_setup() in
1107 drivers/char/ip2/ip2base.c.
1110 When an interrupt is not handled search all handlers
1111 for it. Intended to get systems with badly broken
1115 When an interrupt is not handled search all handlers
1116 for it. Also check all handlers each timer
1117 interrupt. Intended to get systems with badly broken
1121 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1123 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1125 <cpu number>,...,<cpu number>
1127 <cpu number>-<cpu number>
1128 (must be a positive range in ascending order)
1130 <cpu number>,...,<cpu number>-<cpu number>
1132 This option can be used to specify one or more CPUs
1133 to isolate from the general SMP balancing and scheduling
1134 algorithms. You can move a process onto or off an
1135 "isolated" CPU via the CPU affinity syscalls or cpuset.
1136 <cpu number> begins at 0 and the maximum value is
1137 "number of CPUs in system - 1".
1139 This option is the preferred way to isolate CPUs. The
1140 alternative -- manually setting the CPU mask of all
1141 tasks in the system -- can cause problems and
1142 suboptimal load balancer performance.
1146 js= [HW,JOY] Analog joystick
1147 See Documentation/input/joystick.txt.
1151 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1152 specifies the amount of memory usable by the kernel
1153 for non-movable allocations. The requested amount is
1154 spread evenly throughout all nodes in the system. The
1155 remaining memory in each node is used for Movable
1156 pages. In the event, a node is too small to have both
1157 kernelcore and Movable pages, kernelcore pages will
1158 take priority and other nodes will have a larger number
1159 of kernelcore pages. The Movable zone is used for the
1160 allocation of pages that may be reclaimed or moved
1161 by the page migration subsystem. This means that
1162 HugeTLB pages may not be allocated from this zone.
1163 Note that allocations like PTEs-from-HighMem still
1164 use the HighMem zone if it exists, and the Normal
1165 zone if it does not.
1167 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1168 Format: <Controller#>[,poll interval]
1169 The controller # is the number of the ehci usb debug
1170 port as it is probed via PCI. The poll interval is
1171 optional and is the number seconds in between
1172 each poll cycle to the debug port in case you need
1173 the functionality for interrupting the kernel with
1174 gdb or control-c on the dbgp connection. When
1175 not using this parameter you use sysrq-g to break into
1176 the kernel debugger.
1178 kgdboc= [KGDB,HW] kgdb over consoles.
1179 Requires a tty driver that supports console polling,
1180 or a supported polling keyboard driver (non-usb).
1181 Serial only format: <serial_device>[,baud]
1182 keyboard only format: kbd
1183 keyboard and serial format: kbd,<serial_device>[,baud]
1184 Optional Kernel mode setting:
1185 kms, kbd format: kms,kbd
1186 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1188 kgdbwait [KGDB] Stop kernel execution and enter the
1189 kernel debugger at the earliest opportunity.
1191 kmac= [MIPS] korina ethernet MAC address.
1192 Configure the RouterBoard 532 series on-chip
1193 Ethernet adapter MAC address.
1195 kmemleak= [KNL] Boot-time kmemleak enable/disable
1196 Valid arguments: on, off
1199 kstack=N [X86] Print N words from the kernel stack
1202 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1203 Default is 0 (don't ignore, but inject #GP)
1205 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1206 Default is 1 (enabled)
1208 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1212 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1213 Default is 1 (enabled)
1215 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1217 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1219 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1220 (virtualized MMU) support on capable Intel chips.
1221 Default is 1 (enabled)
1223 kvm-intel.emulate_invalid_guest_state=
1224 [KVM,Intel] Enable emulation of invalid guest states
1225 Default is 0 (disabled)
1227 kvm-intel.flexpriority=
1228 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1229 Default is 1 (enabled)
1232 [KVM,Intel] Enable VMX nesting (nVMX).
1233 Default is 0 (disabled)
1235 kvm-intel.unrestricted_guest=
1236 [KVM,Intel] Disable unrestricted guest feature
1237 (virtualized real and unpaged mode) on capable
1238 Intel chips. Default is 1 (enabled)
1240 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1241 feature (tagged TLBs) on capable Intel chips.
1242 Default is 1 (enabled)
1248 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1251 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1254 libata.dma= [LIBATA] DMA control
1255 libata.dma=0 Disable all PATA and SATA DMA
1256 libata.dma=1 PATA and SATA Disk DMA only
1257 libata.dma=2 ATAPI (CDROM) DMA only
1258 libata.dma=4 Compact Flash DMA only
1259 Combinations also work, so libata.dma=3 enables DMA
1260 for disks and CDROMs, but not CFs.
1262 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1263 libata.ignore_hpa=0 keep BIOS limits (default)
1264 libata.ignore_hpa=1 ignore limits, using full disk
1266 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1270 libata.force= [LIBATA] Force configurations. The format is comma
1271 separated list of "[ID:]VAL" where ID is
1272 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1273 matching port, link or device. Basically, it matches
1274 the ATA ID string printed on console by libata. If
1275 the whole ID part is omitted, the last PORT and DEVICE
1276 values are used. If ID hasn't been specified yet, the
1277 configuration applies to all ports, links and devices.
1279 If only DEVICE is omitted, the parameter applies to
1280 the port and all links and devices behind it. DEVICE
1281 number of 0 either selects the first device or the
1282 first fan-out link behind PMP device. It does not
1283 select the host link. DEVICE number of 15 selects the
1284 host link and device attached to it.
1286 The VAL specifies the configuration to force. As long
1287 as there's no ambiguity shortcut notation is allowed.
1288 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1289 The following configurations can be forced.
1291 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1292 Any ID with matching PORT is used.
1294 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1296 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1297 udma[/][16,25,33,44,66,100,133] notation is also
1300 * [no]ncq: Turn on or off NCQ.
1302 * nohrst, nosrst, norst: suppress hard, soft
1305 * dump_id: dump IDENTIFY data.
1307 If there are multiple matching configurations changing
1308 the same attribute, the last one is used.
1310 memblock=debug [KNL] Enable memblock debug messages.
1312 load_ramdisk= [RAM] List of ramdisks to load from floppy
1313 See Documentation/blockdev/ramdisk.txt.
1315 lockd.nlm_grace_period=P [NFS] Assign grace period.
1318 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1321 lockd.nlm_timeout=T [NFS] Assign timeout value.
1324 lockd.nlm_udpport=M [NFS] Assign UDP port.
1327 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1330 loglevel= All Kernel Messages with a loglevel smaller than the
1331 console loglevel will be printed to the console. It can
1332 also be changed with klogd or other programs. The
1333 loglevels are defined as follows:
1335 0 (KERN_EMERG) system is unusable
1336 1 (KERN_ALERT) action must be taken immediately
1337 2 (KERN_CRIT) critical conditions
1338 3 (KERN_ERR) error conditions
1339 4 (KERN_WARNING) warning conditions
1340 5 (KERN_NOTICE) normal but significant condition
1341 6 (KERN_INFO) informational
1342 7 (KERN_DEBUG) debug-level messages
1344 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1345 in bytes. n must be a power of two. The default
1346 size is set in the kernel config file.
1348 logo.nologo [FB] Disables display of the built-in Linux logo.
1349 This may be used to provide more screen space for
1350 kernel log messages and is useful when debugging
1351 kernel boot problems.
1353 lp=0 [LP] Specify parallel ports to use, e.g,
1354 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1355 lp=reset first parallel port). 'lp=0' disables the
1356 lp=auto printer driver. 'lp=reset' (which can be
1357 specified in addition to the ports) causes
1358 attached printers to be reset. Using
1359 lp=port1,port2,... specifies the parallel ports
1360 to associate lp devices with, starting with
1361 lp0. A port specification may be 'none' to skip
1362 that lp device, or a parport name such as
1363 'parport0'. Specifying 'lp=auto' instead of a
1364 port specification list means that device IDs
1365 from each port should be examined, to see if
1366 an IEEE 1284-compliant printer is attached; if
1367 so, the driver will manage that printer.
1368 See also header of drivers/char/lp.c.
1371 Sets loops_per_jiffy to given constant, thus avoiding
1372 time-consuming boot-time autodetection (up to 250 ms per
1373 CPU). 0 enables autodetection (default). To determine
1374 the correct value for your kernel, boot with normal
1375 autodetection and see what value is printed. Note that
1376 on SMP systems the preset will be applied to all CPUs,
1377 which is likely to cause problems if your CPUs need
1378 significantly divergent settings. An incorrect value
1379 will cause delays in the kernel to be wrong, leading to
1380 unpredictable I/O errors and other breakage. Although
1381 unlikely, in the extreme case this might damage your
1385 Format: <io>,<irq>,<dma>
1387 machvec= [IA-64] Force the use of a particular machine-vector
1388 (machvec) in a generic kernel.
1389 Example: machvec=hpzx1_swiotlb
1391 machtype= [Loongson] Share the same kernel image file between different
1393 Example: machtype=lemote-yeeloong-2f-7inch
1395 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1396 than or equal to this physical address is ignored.
1398 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1399 should make use of. maxcpus=n : n >= 0 limits the
1400 kernel to using 'n' processors. n=0 is a special case,
1401 it is equivalent to "nosmp", which also disables
1404 max_loop= [LOOP] The number of loop block devices that get
1405 (loop.max_loop) unconditionally pre-created at init time. The default
1406 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1407 of statically allocating a predefined number, loop
1408 devices can be requested on-demand with the
1409 /dev/loop-control interface.
1413 mce [X86-32] Machine Check Exception
1415 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1417 md= [HW] RAID subsystems devices and level
1418 See Documentation/md.txt.
1421 Format: <first>,<last>
1422 Specifies range of consoles to be captured by the MDA.
1424 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1425 Amount of memory to be used when the kernel is not able
1426 to see the whole system memory or for test.
1427 [X86-32] Use together with memmap= to avoid physical
1428 address space collisions. Without memmap= PCI devices
1429 could be placed at addresses belonging to unused RAM.
1431 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1435 [KNL,SH] Allow user to override the default size for
1436 per-device physically contiguous DMA buffers.
1438 memmap=exactmap [KNL,X86] Enable setting of an exact
1439 E820 memory map, as specified by the user.
1440 Such memmap=exactmap lines can be constructed based on
1441 BIOS output or other requirements. See the memmap=nn@ss
1444 memmap=nn[KMG]@ss[KMG]
1445 [KNL] Force usage of a specific region of memory
1446 Region of memory to be used, from ss to ss+nn.
1448 memmap=nn[KMG]#ss[KMG]
1449 [KNL,ACPI] Mark specific memory as ACPI data.
1450 Region of memory to be used, from ss to ss+nn.
1452 memmap=nn[KMG]$ss[KMG]
1453 [KNL,ACPI] Mark specific memory as reserved.
1454 Region of memory to be used, from ss to ss+nn.
1455 Example: Exclude memory from 0x18690000-0x1869ffff
1456 memmap=64K$0x18690000
1458 memmap=0x10000$0x18690000
1460 memory_corruption_check=0/1 [X86]
1461 Some BIOSes seem to corrupt the first 64k of
1462 memory when doing things like suspend/resume.
1463 Setting this option will scan the memory
1464 looking for corruption. Enabling this will
1465 both detect corruption and prevent the kernel
1466 from using the memory being corrupted.
1467 However, its intended as a diagnostic tool; if
1468 repeatable BIOS-originated corruption always
1469 affects the same memory, you can use memmap=
1470 to prevent the kernel from using that memory.
1472 memory_corruption_check_size=size [X86]
1473 By default it checks for corruption in the low
1474 64k, making this memory unavailable for normal
1475 use. Use this parameter to scan for
1476 corruption in more or less memory.
1478 memory_corruption_check_period=seconds [X86]
1479 By default it checks for corruption every 60
1480 seconds. Use this parameter to check at some
1481 other rate. 0 disables periodic checking.
1483 memtest= [KNL,X86] Enable memtest
1485 default : 0 <disable>
1486 Specifies the number of memtest passes to be
1487 performed. Each pass selects another test
1488 pattern from a given set of patterns. Memtest
1489 fills the memory with this pattern, validates
1490 memory contents and reserves bad memory
1491 regions that are detected.
1493 meye.*= [HW] Set MotionEye Camera parameters
1494 See Documentation/video4linux/meye.txt.
1496 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1497 Multi-Function General Purpose Timers on AMD Geode
1500 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1501 the BIOS has incorrectly applied a workaround. TinyBIOS
1502 version 0.98 is known to be affected, 0.99 fixes the
1503 problem by letting the user disable the workaround.
1507 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1508 physical address is ignored.
1510 mini2440= [ARM,HW,KNL]
1511 Format:[0..2][b][c][t]
1513 MINI2440 configuration specification:
1514 0 - The attached screen is the 3.5" TFT
1515 1 - The attached screen is the 7" TFT
1516 2 - The VGA Shield is attached (1024x768)
1517 Leaving out the screen size parameter will not load
1518 the TFT driver, and the framebuffer will be left
1520 b - Enable backlight. The TFT backlight pin will be
1521 linked to the kernel VESA blanking code and a GPIO
1522 LED. This parameter is not necessary when using the
1524 c - Enable the s3c camera interface.
1525 t - Reserved for enabling touchscreen support. The
1526 touchscreen support is not enabled in the mainstream
1527 kernel as of 2.6.30, a preliminary port can be found
1528 in the "bleeding edge" mini2440 support kernel at
1529 http://repo.or.cz/w/linux-2.6/mini2440.git
1532 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1533 parameter allows control of the logging verbosity for
1534 the additional memory initialisation checks. A value
1535 of 0 disables mminit logging and a level of 4 will
1536 log everything. Information is printed at KERN_DEBUG
1537 so loglevel=8 may also need to be specified.
1540 [MOUSE] Maximum time between finger touching and
1541 leaving touchpad surface for touch to be considered
1542 a tap and be reported as a left button click (for
1543 touchpads working in absolute mode only).
1545 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1546 reporting absolute coordinates, such as tablets
1547 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1548 reporting absolute coordinates, such as tablets
1550 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1551 is similar to kernelcore except it specifies the
1552 amount of memory used for migratable allocations.
1553 If both kernelcore and movablecore is specified,
1554 then kernelcore will be at *least* the specified
1555 value but may be more. If movablecore on its own
1556 is specified, the administrator must be careful
1557 that the amount of memory usable for all allocations
1560 MTD_Partition= [MTD]
1561 Format: <name>,<region-number>,<size>,<offset>
1563 MTD_Region= [MTD] Format:
1564 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1567 See drivers/mtd/cmdlinepart.c.
1569 multitce=off [PPC] This parameter disables the use of the pSeries
1570 firmware feature for updating multiple TCE entries
1573 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1575 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1577 boundary - index of last SLC block on Flex-OneNAND.
1578 The remaining blocks are configured as MLC blocks.
1579 lock - Configure if Flex-OneNAND boundary should be locked.
1580 Once locked, the boundary cannot be changed.
1581 1 indicates lock status, 0 indicates unlock status.
1584 ARM/S3C2412 JIVE boot control
1586 See arch/arm/mach-s3c2412/mach-jive.c
1588 mtouchusb.raw_coordinates=
1589 [HW] Make the MicroTouch USB driver use raw coordinates
1590 ('y', default) or cooked coordinates ('n')
1592 mtrr_chunk_size=nn[KMG] [X86]
1593 used for mtrr cleanup. It is largest continuous chunk
1594 that could hold holes aka. UC entries.
1596 mtrr_gran_size=nn[KMG] [X86]
1597 Used for mtrr cleanup. It is granularity of mtrr block.
1599 Large value could prevent small alignment from
1602 mtrr_spare_reg_nr=n [X86]
1604 Range: 0,7 : spare reg number
1606 Used for mtrr cleanup. It is spare mtrr entries number.
1607 Set to 2 or more if your graphical card needs more.
1609 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1611 netdev= [NET] Network devices parameters
1612 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1613 Note that mem_start is often overloaded to mean
1614 something different and driver-specific.
1615 This usage is only documented in each driver source
1619 [NETFILTER] Enable connection tracking flow accounting
1620 0 to disable accounting
1621 1 to enable accounting
1624 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1625 See Documentation/filesystems/nfs/nfsroot.txt.
1627 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1628 See Documentation/filesystems/nfs/nfsroot.txt.
1630 nfsrootdebug [NFS] enable nfsroot debugging messages.
1631 See Documentation/filesystems/nfs/nfsroot.txt.
1633 nfs.callback_tcpport=
1634 [NFS] set the TCP port on which the NFSv4 callback
1635 channel should listen.
1638 [NFS] sets the pathname to the program which is used
1639 to update the NFS client cache entries.
1641 nfs.cache_getent_timeout=
1642 [NFS] sets the timeout after which an attempt to
1643 update a cache entry is deemed to have failed.
1645 nfs.idmap_cache_timeout=
1646 [NFS] set the maximum lifetime for idmapper cache
1650 [NFS] enable 64-bit inode numbers.
1651 If zero, the NFS client will fake up a 32-bit inode
1652 number for the readdir() and stat() syscalls instead
1653 of returning the full 64-bit number.
1654 The default is to return 64-bit inode numbers.
1656 nfs.nfs4_disable_idmapping=
1657 [NFSv4] When set, this option disables the NFSv4
1658 idmapper on the client, but only if the mount
1659 is using the 'sec=sys' security flavour. This may
1660 make migration from legacy NFSv2/v3 systems easier
1661 provided that the server has the appropriate support.
1662 The default is to always enable NFSv4 idmapping.
1664 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1665 when a NMI is triggered.
1666 Format: [state][,regs][,debounce][,die]
1668 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1669 Format: [panic,][nopanic,][num]
1671 0 - turn nmi_watchdog off
1672 When panic is specified, panic when an NMI watchdog
1673 timeout occurs (or 'nopanic' to override the opposite
1675 This is useful when you use a panic=... timeout and
1676 need the box quickly up again.
1678 netpoll.carrier_timeout=
1679 [NET] Specifies amount of time (in seconds) that
1680 netpoll should wait for a carrier. By default netpoll
1683 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1684 emulation library even if a 387 maths coprocessor
1688 [HW] Never suspend the console
1689 Disable suspending of consoles during suspend and
1690 hibernate operations. Once disabled, debugging
1691 messages can reach various consoles while the rest
1692 of the system is being put to sleep (ie, while
1693 debugging driver suspend/resume hooks). This may
1694 not work reliably with all consoles, but is known
1695 to work with serial and VGA consoles.
1696 To facilitate more flexible debugging, we also add
1697 console_suspend, a printk module parameter to control
1698 it. Users could use console_suspend (usually
1699 /sys/module/printk/parameters/console_suspend) to
1700 turn on/off it dynamically.
1702 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1703 caches in the slab allocator. Saves per-node memory,
1704 but will impact performance.
1708 noapic [SMP,APIC] Tells the kernel to not make use of any
1709 IOAPICs that may be present in the system.
1711 noautogroup Disable scheduler automatic task group creation.
1713 nobats [PPC] Do not use BATs for mapping kernel lowmem
1714 on "Classic" PPC cores.
1718 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1720 nodelayacct [KNL] Disable per-task delay accounting
1722 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1724 nodsp [SH] Disable hardware DSP at boot time.
1726 noefi [X86] Disable EFI runtime services support.
1731 On X86-32 available only on PAE configured kernels.
1732 noexec=on: enable non-executable mappings (default)
1733 noexec=off: disable non-executable mappings
1736 Disable SMEP (Supervisor Mode Execution Protection)
1737 even if it is supported by processor.
1740 This affects only 32-bit executables.
1741 noexec32=on: enable non-executable mappings (default)
1742 read doesn't imply executable mappings
1743 noexec32=off: disable non-executable mappings
1744 read implies executable mappings
1746 nofpu [SH] Disable hardware FPU at boot time.
1748 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1749 register save and restore. The kernel will only save
1750 legacy floating-point registers on task switch.
1752 noxsave [BUGS=X86] Disables x86 extended register state save
1753 and restore using xsave. The kernel will fallback to
1754 enabling legacy floating-point and sse state.
1756 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1757 wfi(ARM) instruction doesn't work correctly and not to
1758 use it. This is also useful when using JTAG debugger.
1760 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1761 instruction doesn't work correctly and not to
1764 no_file_caps Tells the kernel not to honor file capabilities. The
1765 only way then for a file to be executed with privilege
1766 is to be setuid root or executed by root.
1768 nohalt [IA-64] Tells the kernel not to use the power saving
1769 function PAL_HALT_LIGHT when idle. This increases
1770 power-consumption. On the positive side, it reduces
1771 interrupt wake-up latency, which may improve performance
1772 in certain environments such as networked servers or
1775 nohz= [KNL] Boottime enable/disable dynamic ticks
1776 Valid arguments: on, off
1779 noiotrap [SH] Disables trapped I/O port accesses.
1781 noirqdebug [X86-32] Disables the code which attempts to detect and
1782 disable unhandled interrupt sources.
1784 no_timer_check [X86,APIC] Disables the code which tests for
1785 broken timer IRQ sources.
1787 noisapnp [ISAPNP] Disables ISA PnP code.
1789 noinitrd [RAM] Tells the kernel not to load any configured
1792 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1794 [Deprecated - use intremap=off]
1798 nojitter [IA-64] Disables jitter checking for ITC timers.
1800 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1802 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1805 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1806 steal time is computed, but won't influence scheduler
1809 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1811 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1813 noltlbs [PPC] Do not use large page/tlb entries for kernel
1814 lowmem mapping on PPC40x.
1816 nomca [IA-64] Disable machine check abort handling
1818 nomce [X86-32] Machine Check Exception
1820 nomfgpt [X86-32] Disable Multi-Function General Purpose
1821 Timer usage (for AMD Geode machines).
1823 nopat [X86] Disable PAT (page attribute table extension of
1824 pagetables) support.
1826 norandmaps Don't use address space randomization. Equivalent to
1827 echo 0 > /proc/sys/kernel/randomize_va_space
1829 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1831 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1832 with UP alternatives
1834 noresidual [PPC] Don't use residual data on PReP machines.
1836 nordrand [X86] Disable the direct use of the RDRAND
1837 instruction even if it is supported by the
1838 processor. RDRAND is still available to user
1841 noresume [SWSUSP] Disables resume and restores original swap
1844 no-scroll [VGA] Disables scrollback.
1845 This is required for the Braillex ib80-piezo Braille
1846 reader made by F.H. Papenmeier (Germany).
1850 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1852 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1853 and disable the IO APIC. legacy for "maxcpus=0".
1855 nosoftlockup [KNL] Disable the soft-lockup detector.
1857 nosync [HW,M68K] Disables sync negotiation for all devices.
1859 notsc [BUGS=X86-32] Disable Time Stamp Counter
1861 nousb [USB] Disable the USB subsystem
1863 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1867 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1869 nptcg= [IA-64] Override max number of concurrent global TLB
1870 purges which is reported from either PAL_VM_SUMMARY or
1873 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1874 could support. nr_cpus=n : n >= 1 limits the kernel to
1875 supporting 'n' processors. Later in runtime you can not
1876 use hotplug cpu feature to put more cpu back to online.
1877 just like you compile the kernel NR_CPUS=n
1879 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1881 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1882 one of ['zone', 'node', 'default'] can be specified
1883 This can be set from sysctl after boot.
1884 See Documentation/sysctl/vm.txt for details.
1886 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1887 See Documentation/debugging-via-ohci1394.txt for more
1890 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1891 Rather than timing out after 20 ms if an EC
1892 command is not properly ACKed, override the length
1893 of the timeout. We have interrupts disabled while
1894 waiting for the ACK, so if this is set too high
1895 interrupts *may* be lost!
1897 omap_mux= [OMAP] Override bootloader pin multiplexing.
1898 Format: <mux_mode0.mode_name=value>...
1899 For example, to override I2C bus2:
1900 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1902 oprofile.timer= [HW]
1903 Use timer interrupt instead of performance counters
1905 oprofile.cpu_type= Force an oprofile cpu type
1906 This might be useful if you have an older oprofile
1907 userland or if you want common events.
1908 Format: { arch_perfmon }
1909 arch_perfmon: [X86] Force use of architectural
1910 perfmon on Intel CPUs instead of the
1911 CPU specific event set.
1913 oops=panic Always panic on oopses. Default is to just kill the
1914 process, but there is a small probability of
1915 deadlocking the machine.
1916 This will also cause panics on machine check exceptions.
1917 Useful together with panic=30 to trigger a reboot.
1920 See Documentation/sound/oss/oss-parameters.txt
1922 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1923 timeout > 0: seconds before rebooting
1924 timeout = 0: wait forever
1925 timeout < 0: reboot immediately
1928 parkbd.port= [HW] Parallel port number the keyboard adapter is
1929 connected to, default is 0.
1931 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1932 0 for XT, 1 for AT (default is AT).
1935 parport= [HW,PPT] Specify parallel ports. 0 disables.
1936 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1937 Use 'auto' to force the driver to use any
1938 IRQ/DMA settings detected (the default is to
1939 ignore detected IRQ/DMA settings because of
1940 possible conflicts). You can specify the base
1941 address, IRQ, and DMA settings; IRQ and DMA
1942 should be numbers, or 'auto' (for using detected
1943 settings on that particular port), or 'nofifo'
1944 (to avoid using a FIFO even if it is detected).
1945 Parallel ports are assigned in the order they
1946 are specified on the command line, starting
1949 parport_init_mode= [HW,PPT]
1950 Configure VIA parallel port to operate in
1951 a specific mode. This is necessary on Pegasos
1952 computer where firmware has no options for setting
1953 up parallel port mode and sets it to spp.
1954 Currently this function knows 686a and 8231 chips.
1955 Format: [spp|ps2|epp|ecp|ecpepp]
1958 Halt all CPUs after the first oops has been printed for
1959 the specified number of seconds. This is to be used if
1960 your oopses keep scrolling off the screen.
1965 See header of drivers/block/paride/pcd.c.
1966 See also Documentation/blockdev/paride.txt.
1968 pci=option[,option...] [PCI] various PCI subsystem options:
1969 earlydump [X86] dump PCI config space before the kernel
1971 off [X86] don't probe for the PCI bus
1972 bios [X86-32] force use of PCI BIOS, don't access
1973 the hardware directly. Use this if your machine
1974 has a non-standard PCI host bridge.
1975 nobios [X86-32] disallow use of PCI BIOS, only direct
1976 hardware access methods are allowed. Use this
1977 if you experience crashes upon bootup and you
1978 suspect they are caused by the BIOS.
1979 conf1 [X86] Force use of PCI Configuration
1981 conf2 [X86] Force use of PCI Configuration
1983 noaer [PCIE] If the PCIEAER kernel config parameter is
1984 enabled, this kernel boot option can be used to
1985 disable the use of PCIE advanced error reporting.
1986 nodomains [PCI] Disable support for multiple PCI
1987 root domains (aka PCI segments, in ACPI-speak).
1988 nommconf [X86] Disable use of MMCONFIG for PCI
1990 check_enable_amd_mmconf [X86] check for and enable
1991 properly configured MMIO access to PCI
1992 config space on AMD family 10h CPU
1993 nomsi [MSI] If the PCI_MSI kernel config parameter is
1994 enabled, this kernel boot option can be used to
1995 disable the use of MSI interrupts system-wide.
1996 noioapicquirk [APIC] Disable all boot interrupt quirks.
1997 Safety option to keep boot IRQs enabled. This
1998 should never be necessary.
1999 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
2000 primary IO-APIC for bridges that cannot disable
2001 boot IRQs. This fixes a source of spurious IRQs
2002 when the system masks IRQs.
2003 noioapicreroute [APIC] Disable workaround that uses the
2004 boot IRQ equivalent of an IRQ that connects to
2005 a chipset where boot IRQs cannot be disabled.
2006 The opposite of ioapicreroute.
2007 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
2008 routing table. These calls are known to be buggy
2009 on several machines and they hang the machine
2010 when used, but on other computers it's the only
2011 way to get the interrupt routing table. Try
2012 this option if the kernel is unable to allocate
2013 IRQs or discover secondary PCI buses on your
2015 rom [X86] Assign address space to expansion ROMs.
2016 Use with caution as certain devices share
2017 address decoders between ROMs and other
2019 norom [X86] Do not assign address space to
2020 expansion ROMs that do not already have
2021 BIOS assigned address ranges.
2022 nobar [X86] Do not assign address space to the
2023 BARs that weren't assigned by the BIOS.
2024 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
2025 assigned automatically to PCI devices. You can
2026 make the kernel exclude IRQs of your ISA cards
2028 pirqaddr=0xAAAAA [X86] Specify the physical address
2029 of the PIRQ table (normally generated
2030 by the BIOS) if it is outside the
2031 F0000h-100000h range.
2032 lastbus=N [X86] Scan all buses thru bus #N. Can be
2033 useful if the kernel is unable to find your
2034 secondary buses and you want to tell it
2035 explicitly which ones they are.
2036 assign-busses [X86] Always assign all PCI bus
2037 numbers ourselves, overriding
2038 whatever the firmware may have done.
2039 usepirqmask [X86] Honor the possible IRQ mask stored
2040 in the BIOS $PIR table. This is needed on
2041 some systems with broken BIOSes, notably
2042 some HP Pavilion N5400 and Omnibook XE3
2043 notebooks. This will have no effect if ACPI
2044 IRQ routing is enabled.
2045 noacpi [X86] Do not use ACPI for IRQ routing
2046 or for PCI scanning.
2047 use_crs [X86] Use PCI host bridge window information
2048 from ACPI. On BIOSes from 2008 or later, this
2049 is enabled by default. If you need to use this,
2050 please report a bug.
2051 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2052 If you need to use this, please report a bug.
2053 routeirq Do IRQ routing for all PCI devices.
2054 This is normally done in pci_enable_device(),
2055 so this option is a temporary workaround
2056 for broken drivers that don't call it.
2057 skip_isa_align [X86] do not align io start addr, so can
2058 handle more pci cards
2059 firmware [ARM] Do not re-enumerate the bus but instead
2060 just use the configuration from the
2061 bootloader. This is currently used on
2062 IXP2000 systems where the bus has to be
2063 configured a certain way for adjunct CPUs.
2064 noearly [X86] Don't do any early type 1 scanning.
2065 This might help on some broken boards which
2066 machine check when some devices' config space
2067 is read. But various workarounds are disabled
2068 and some IOMMU drivers will not work.
2069 bfsort Sort PCI devices into breadth-first order.
2070 This sorting is done to get a device
2071 order compatible with older (<= 2.4) kernels.
2072 nobfsort Don't sort PCI devices into breadth-first order.
2073 cbiosize=nn[KMG] The fixed amount of bus space which is
2074 reserved for the CardBus bridge's IO window.
2075 The default value is 256 bytes.
2076 cbmemsize=nn[KMG] The fixed amount of bus space which is
2077 reserved for the CardBus bridge's memory
2078 window. The default value is 64 megabytes.
2081 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2082 Specifies alignment and device to reassign
2083 aligned memory resources.
2084 If <order of align> is not specified,
2085 PAGE_SIZE is used as alignment.
2086 PCI-PCI bridge can be specified, if resource
2087 windows need to be expanded.
2088 ecrc= Enable/disable PCIe ECRC (transaction layer
2089 end-to-end CRC checking).
2090 bios: Use BIOS/firmware settings. This is the
2094 realloc reallocate PCI resources if allocations done by BIOS
2097 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2100 force Enable ASPM even on devices that claim not to support it.
2101 WARNING: Forcing ASPM on may cause system lockups.
2103 pcie_ports= [PCIE] PCIe ports handling:
2104 auto Ask the BIOS whether or not to use native PCIe services
2105 associated with PCIe ports (PME, hot-plug, AER). Use
2106 them only if that is allowed by the BIOS.
2107 native Use native PCIe services associated with PCIe ports
2109 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2112 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2113 nomsi Do not use MSI for native PCIe PME signaling (this makes
2114 all PCIe root ports use INTx for all services).
2116 pcmv= [HW,PCMCIA] BadgePAD 4
2119 See Documentation/blockdev/paride.txt.
2121 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2124 See arch/parisc/kernel/pdc_chassis.c
2126 percpu_alloc= Select which percpu first chunk allocator to use.
2127 Currently supported values are "embed" and "page".
2128 Archs may support subset or none of the selections.
2129 See comments in mm/percpu.c for details on each
2130 allocator. This parameter is primarily for debugging
2131 and performance comparison.
2134 See Documentation/blockdev/paride.txt.
2137 See Documentation/blockdev/paride.txt.
2139 pirq= [SMP,APIC] Manual mp-table setup
2140 See Documentation/x86/i386/IO-APIC.txt.
2142 plip= [PPT,NET] Parallel port network link
2143 Format: { parport<nr> | timid | 0 }
2144 See also Documentation/parport.txt.
2146 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2147 Override pmtimer IOPort with a hex value.
2151 Enable PNP debug messages (depends on the
2152 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2153 via /sys/module/pnp/parameters/debug. We always show
2154 current resource usage; turning this on also shows
2155 possible settings and some assignment information.
2161 { on | off | curr | res | no-curr | no-res }
2164 [ISAPNP] Exclude IRQs for the autoconfiguration
2167 [ISAPNP] Exclude DMAs for the autoconfiguration
2169 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2170 Ranges are in pairs (I/O port base and size).
2173 [ISAPNP] Exclude memory regions for the
2175 Ranges are in pairs (memory base and size).
2177 ports= [IP_VS_FTP] IPVS ftp helper module
2179 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2181 Format: <port>,<port>....
2183 print-fatal-signals=
2184 [KNL] debug: print fatal signals
2186 If enabled, warn about various signal handling
2187 related application anomalies: too many signals,
2188 too many POSIX.1 timers, fatal signals causing a
2191 If you hit the warning due to signal overflow,
2192 you might want to try "ulimit -i unlimited".
2196 printk.time= Show timing data prefixed to each printk message line
2197 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2199 processor.max_cstate= [HW,ACPI]
2200 Limit processor to maximum C-state
2201 max_cstate=9 overrides any DMI blacklist limit.
2203 processor.nocst [HW,ACPI]
2204 Ignore the _CST method to determine C-states,
2205 instead using the legacy FADT method
2207 profile= [KNL] Enable kernel profiling via /proc/profile
2208 Format: [schedule,]<number>
2209 Param: "schedule" - profile schedule points.
2210 Param: <number> - step/bucket size as a power of 2 for
2211 statistical time based profiling.
2212 Param: "sleep" - profile D-state sleeping (millisecs).
2213 Requires CONFIG_SCHEDSTATS
2214 Param: "kvm" - profile VM exits.
2216 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2218 See Documentation/blockdev/ramdisk.txt.
2220 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2221 probe for; one of (bare|imps|exps|lifebook|any).
2222 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2224 psmouse.resetafter= [HW,MOUSE]
2225 Try to reset the device after so many bad packets
2228 [HW,MOUSE] Set desired mouse resolution, in dpi.
2229 psmouse.smartscroll=
2230 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2231 0 = disabled, 1 = enabled (default).
2233 pstore.backend= Specify the name of the pstore backend to use
2236 See Documentation/blockdev/paride.txt.
2239 [KNL] Number of legacy pty's. Overwrites compiled-in
2242 quiet [KNL] Disable most log messages
2247 See Documentation/md.txt.
2249 ramdisk_blocksize= [RAM]
2250 See Documentation/blockdev/ramdisk.txt.
2252 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2253 See Documentation/blockdev/ramdisk.txt.
2255 rcupdate.blimit= [KNL,BOOT]
2256 Set maximum number of finished RCU callbacks to process
2259 rcupdate.qhimark= [KNL,BOOT]
2260 Set threshold of queued
2261 RCU callbacks over which batch limiting is disabled.
2263 rcupdate.qlowmark= [KNL,BOOT]
2264 Set threshold of queued RCU callbacks below which
2265 batch limiting is re-enabled.
2269 Run specified binary instead of /init from the ramdisk,
2270 used for early userspace startup. See initrd.
2272 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2273 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2274 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2277 [KNL, SMP] Set scheduler's default relax_domain_level.
2278 See Documentation/cgroups/cpusets.txt.
2280 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2282 reservetop= [X86-32]
2284 Reserves a hole at the top of the kernel virtual
2289 Set the amount of memory to reserve for BIOS at
2290 the bottom of the address space.
2292 reset_devices [KNL] Force drivers to reset the underlying device
2293 during initialization.
2296 Specify the partition device for software suspend
2298 resume_offset= [SWSUSP]
2299 Specify the offset from the beginning of the partition
2300 given by "resume=" at which the swap header is located,
2301 in <PAGE_SIZE> units (needed only for swap files).
2302 See Documentation/power/swsusp-and-swap-files.txt
2304 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
2305 read the resume files
2307 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
2308 Useful for devices that are detected asynchronously
2309 (e.g. USB and MMC devices).
2311 hibernate= [HIBERNATION]
2312 noresume Don't check if there's a hibernation image
2313 present during boot.
2314 nocompress Don't compress/decompress hibernation images.
2316 retain_initrd [RAM] Keep initrd memory after extraction
2318 rhash_entries= [KNL,NET]
2319 Set number of hash buckets for route cache
2321 riscom8= [HW,SERIAL]
2322 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2324 ro [KNL] Mount root device read-only on boot
2326 root= [KNL] Root filesystem
2327 See name_to_dev_t comment in init/do_mounts.c.
2329 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2330 mount the root filesystem
2332 rootflags= [KNL] Set root filesystem mount option string
2334 rootfstype= [KNL] Set root filesystem type
2336 rootwait [KNL] Wait (indefinitely) for root device to show up.
2337 Useful for devices that are detected asynchronously
2338 (e.g. USB and MMC devices).
2340 rw [KNL] Mount root device read-write on boot
2342 S [KNL] Run init in single mode
2345 See drivers/net/irda/sa1100_ir.c.
2347 sbni= [NET] Granch SBNI12 leased line adapter
2349 sched_debug [KNL] Enables verbose scheduler debug messages.
2351 security= [SECURITY] Choose a security module to enable at boot.
2352 If this boot parameter is not specified, only the first
2353 security module asking for security registration will be
2354 loaded. An invalid security module name will be treated
2355 as if no module has been chosen.
2357 selinux= [SELINUX] Disable or enable SELinux at boot time.
2358 Format: { "0" | "1" }
2359 See security/selinux/Kconfig help text.
2362 Default value is set via kernel config option.
2363 If enabled at boot time, /selinux/disable can be used
2364 later to disable prior to initial policy load.
2366 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2367 Format: { "0" | "1" }
2368 See security/apparmor/Kconfig help text
2371 Default value is set via kernel config option.
2373 serialnumber [BUGS=X86-32]
2376 Maximal number of shapers.
2378 show_msr= [x86] show boot-time MSR settings
2379 Format: { <integer> }
2380 Show boot-time (BIOS-initialized) MSR settings.
2381 The parameter means the number of CPUs to show,
2382 for example 1 means boot CPU only.
2389 slub_debug[=options[,slabs]] [MM, SLUB]
2390 Enabling slub_debug allows one to determine the
2391 culprit if slab objects become corrupted. Enabling
2392 slub_debug can create guard zones around objects and
2393 may poison objects when not in use. Also tracks the
2394 last alloc / free. For more information see
2395 Documentation/vm/slub.txt.
2397 slub_max_order= [MM, SLUB]
2398 Determines the maximum allowed order for slabs.
2399 A high setting may cause OOMs due to memory
2400 fragmentation. For more information see
2401 Documentation/vm/slub.txt.
2403 slub_min_objects= [MM, SLUB]
2404 The minimum number of objects per slab. SLUB will
2405 increase the slab order up to slub_max_order to
2406 generate a sufficiently large slab able to contain
2407 the number of objects indicated. The higher the number
2408 of objects the smaller the overhead of tracking slabs
2409 and the less frequently locks need to be acquired.
2410 For more information see Documentation/vm/slub.txt.
2412 slub_min_order= [MM, SLUB]
2413 Determines the mininum page order for slabs. Must be
2414 lower than slub_max_order.
2415 For more information see Documentation/vm/slub.txt.
2417 slub_nomerge [MM, SLUB]
2418 Disable merging of slabs with similar size. May be
2419 necessary if there is some reason to distinguish
2420 allocs to different slabs. Debug options disable
2421 merging on their own.
2422 For more information see Documentation/vm/slub.txt.
2425 Format: <io1>[,<io2>[,...,<io8>]]
2427 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2428 attempt to substitute SMP alternatives once at boot.
2430 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2431 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2432 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2433 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2434 smsc-ircc2.ircc_irq= [HW] IRQ line
2435 smsc-ircc2.ircc_dma= [HW] DMA channel
2436 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2437 0: Toshiba Satellite 1800 (GP data pin select)
2438 1: Fast pin select (default)
2442 [KNL] Should the soft-lockup detector generate panics.
2445 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2446 See Documentation/laptops/sonypi.txt
2448 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2449 See Documentation/serial/specialix.txt.
2451 spia_io_base= [HW,MTD]
2457 Enabled the stack tracer on boot up.
2461 Set the STI (builtin display/keyboard on the HP-PARISC
2462 machines) console (graphic card) which should be used
2463 as the initial boot-console.
2464 See also comment in drivers/video/console/sticore.c.
2467 See comment in drivers/video/console/sticore.c.
2470 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2472 sunrpc.min_resvport=
2473 sunrpc.max_resvport=
2475 SunRPC servers often require that client requests
2476 originate from a privileged port (i.e. a port in the
2477 range 0 < portnr < 1024).
2478 An administrator who wishes to reserve some of these
2479 ports for other uses may adjust the range that the
2480 kernel's sunrpc client considers to be privileged
2481 using these two parameters to set the minimum and
2482 maximum port values.
2486 Control how the NFS server code allocates CPUs to
2487 service thread pools. Depending on how many NICs
2488 you have and where their interrupts are bound, this
2489 option will affect which CPUs will do NFS serving.
2490 Note: this parameter cannot be changed while the
2491 NFS server is running.
2493 auto the server chooses an appropriate mode
2494 automatically using heuristics
2495 global a single global pool contains all CPUs
2496 percpu one pool for each CPU
2497 pernode one pool for each NUMA node (equivalent
2498 to global on non-NUMA machines)
2500 sunrpc.tcp_slot_table_entries=
2501 sunrpc.udp_slot_table_entries=
2503 Sets the upper limit on the number of simultaneous
2504 RPC calls that can be sent from the client to a
2505 server. Increasing these values may allow you to
2506 improve throughput, but will also increase the
2507 amount of memory reserved for use by the client.
2510 [KNL] Enable accounting of swap in memory resource
2511 controller if no parameter or 1 is given or disable
2512 it if 0 is given (See Documentation/cgroups/memory.txt)
2514 swiotlb= [IA-64] Number of I/O TLB slabs
2518 sysfs.deprecated=0|1 [KNL]
2519 Enable/disable old style sysfs layout for old udev
2520 on older distributions. When this option is enabled
2521 very new udev will not work anymore. When this option
2522 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2523 in older udev will not work anymore.
2524 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2525 the kernel configuration.
2527 sysrq_always_enabled
2529 Ignore sysrq setting - this boot parameter will
2530 neutralize any effect of /proc/sys/kernel/sysrq.
2531 Useful for debugging.
2535 test_suspend= [SUSPEND]
2536 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2537 standby suspend) as the system sleep state to briefly
2538 enter during system startup. The system is woken from
2539 this state using a wakeup-capable RTC alarm.
2541 thash_entries= [KNL,NET]
2542 Set number of hash buckets for TCP connection
2544 thermal.act= [HW,ACPI]
2545 -1: disable all active trip points in all thermal zones
2546 <degrees C>: override all lowest active trip points
2548 thermal.crt= [HW,ACPI]
2549 -1: disable all critical trip points in all thermal zones
2550 <degrees C>: override all critical trip points
2552 thermal.nocrt= [HW,ACPI]
2553 Set to disable actions on ACPI thermal zone
2554 critical and hot trip points.
2556 thermal.off= [HW,ACPI]
2557 1: disable ACPI thermal control
2559 thermal.psv= [HW,ACPI]
2560 -1: disable all passive trip points
2561 <degrees C>: override all passive trip points to this
2564 thermal.tzp= [HW,ACPI]
2565 Specify global default ACPI thermal zone polling rate
2566 <deci-seconds>: poll all this frequency
2567 0: no polling (default)
2570 Force threading of all interrupt handlers except those
2571 marked explicitely IRQF_NO_THREAD.
2575 Specify if the kernel should make use of the cpu
2576 topology information if the hardware supports this.
2577 The scheduler will make use of this information and
2578 e.g. base its process migration decisions on it.
2583 tpm_suspend_pcr=[HW,TPM]
2584 Format: integer pcr id
2585 Specify that at suspend time, the tpm driver
2586 should extend the specified pcr with zeros,
2587 as a workaround for some chips which fail to
2588 flush the last written pcr on TPM_SaveState.
2589 This will guarantee that all the other pcrs
2592 trace_buf_size=nn[KMG]
2593 [FTRACE] will set tracing buffer size.
2595 trace_event=[event-list]
2596 [FTRACE] Set and start specified trace events in order
2597 to facilitate early boot debugging.
2598 See also Documentation/trace/events.txt
2600 tsc= Disable clocksource stability checks for TSC.
2602 [x86] reliable: mark tsc clocksource as reliable, this
2603 disables clocksource verification at runtime, as well
2604 as the stability checks done at bootup. Used to enable
2605 high-resolution timer mode on older hardware, and in
2606 virtualized environment.
2607 [x86] noirqtime: Do not use TSC to do irq accounting.
2608 Used to run time disable IRQ_TIME_ACCOUNTING on any
2609 platforms where RDTSC is slow and this accounting
2612 turbografx.map[2|3]= [HW,JOY]
2613 TurboGraFX parallel port interface
2615 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2616 See also Documentation/input/joystick-parport.txt
2618 udbg-immortal [PPC] When debugging early kernel crashes that
2619 happen after console_init() and before a proper
2620 console driver takes over, this boot options might
2621 help "seeing" what's going on.
2623 uhash_entries= [KNL,NET]
2624 Set number of hash buckets for UDP/UDP-Lite connections
2627 [USB] Ignore overcurrent events (default N).
2628 Some badly-designed motherboards generate lots of
2629 bogus events, for ports that aren't wired to
2630 anything. Set this parameter to avoid log spamming.
2631 Note that genuine overcurrent events won't be
2635 [X86] Cause panic on unknown NMI.
2637 usbcore.authorized_default=
2638 [USB] Default USB device authorization:
2639 (default -1 = authorized except for wireless USB,
2640 0 = not authorized, 1 = authorized)
2642 usbcore.autosuspend=
2643 [USB] The autosuspend time delay (in seconds) used
2644 for newly-detected USB devices (default 2). This
2645 is the time required before an idle device will be
2646 autosuspended. Devices for which the delay is set
2647 to a negative value won't be autosuspended at all.
2649 usbcore.usbfs_snoop=
2650 [USB] Set to log all usbfs traffic (default 0 = off).
2652 usbcore.blinkenlights=
2653 [USB] Set to cycle leds on hubs (default 0 = off).
2655 usbcore.old_scheme_first=
2656 [USB] Start with the old device initialization
2657 scheme (default 0 = off).
2659 usbcore.use_both_schemes=
2660 [USB] Try the other device initialization scheme
2661 if the first one fails (default 1 = enabled).
2663 usbcore.initial_descriptor_timeout=
2664 [USB] Specifies timeout for the initial 64-byte
2665 USB_REQ_GET_DESCRIPTOR request in milliseconds
2666 (default 5000 = 5.0 seconds).
2669 [USBHID] The interval which mice are to be polled at.
2671 usb-storage.delay_use=
2672 [UMS] The delay in seconds before a new device is
2673 scanned for Logical Units (default 5).
2676 [UMS] A list of quirks entries to supplement or
2677 override the built-in unusual_devs list. List
2678 entries are separated by commas. Each entry has
2679 the form VID:PID:Flags where VID and PID are Vendor
2680 and Product ID values (4-digit hex numbers) and
2681 Flags is a set of characters, each corresponding
2682 to a common usb-storage quirk flag as follows:
2683 a = SANE_SENSE (collect more than 18 bytes
2685 b = BAD_SENSE (don't collect more than 18
2686 bytes of sense data);
2687 c = FIX_CAPACITY (decrease the reported
2688 device capacity by one sector);
2689 d = NO_READ_DISC_INFO (don't use
2690 READ_DISC_INFO command);
2691 e = NO_READ_CAPACITY_16 (don't use
2692 READ_CAPACITY_16 command);
2693 h = CAPACITY_HEURISTICS (decrease the
2694 reported device capacity by one
2695 sector if the number is odd);
2696 i = IGNORE_DEVICE (don't bind to this
2698 l = NOT_LOCKABLE (don't try to lock and
2699 unlock ejectable media);
2700 m = MAX_SECTORS_64 (don't transfer more
2701 than 64 sectors = 32 KB at a time);
2702 n = INITIAL_READ10 (force a retry of the
2703 initial READ(10) command);
2704 o = CAPACITY_OK (accept the capacity
2705 reported by the device);
2706 r = IGNORE_RESIDUE (the device reports
2707 bogus residue values);
2708 s = SINGLE_LUN (the device has only one
2710 w = NO_WP_DETECT (don't test whether the
2711 medium is write-protected).
2712 Example: quirks=0419:aaf5:rl,0421:0433:rc
2714 user_debug= [KNL,ARM]
2716 See arch/arm/Kconfig.debug help text.
2717 1 - undefined instruction events
2719 4 - invalid data aborts
2722 Example: user_debug=31
2725 [X86] Flags controlling user PTE allocations.
2727 nohigh = do not allocate PTE pages in
2728 HIGHMEM regardless of setting
2732 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2733 vdso=1: enable VDSO (default)
2734 vdso=0: disable VDSO mapping
2737 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2738 vdso32=1: enable 32-bit VDSO (default)
2739 vdso32=0: disable 32-bit VDSO mapping
2742 vector=percpu: enable percpu vector domain
2744 video= [FB] Frame buffer configuration
2745 See Documentation/fb/modedb.txt.
2747 vga= [BOOT,X86-32] Select a particular video mode
2748 See Documentation/x86/boot.txt and
2749 Documentation/svga.txt.
2750 Use vga=ask for menu.
2751 This is actually a boot loader parameter; the value is
2752 passed to the kernel using a special protocol.
2754 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2755 size of <nn>. This can be used to increase the
2756 minimum size (128MB on x86). It can also be used to
2757 decrease the size and leave more room for directly
2760 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2763 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2766 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2770 Controls the behavior of vsyscalls (i.e. calls to
2771 fixed addresses of 0xffffffffff600x00 from legacy
2772 code). Most statically-linked binaries and older
2773 versions of glibc use these calls. Because these
2774 functions are at fixed addresses, they make nice
2775 targets for exploits that can control RIP.
2777 emulate Vsyscalls turn into traps and are emulated
2780 native [default] Vsyscalls are native syscall
2782 This is a little bit faster than trapping
2783 and makes a few dynamic recompilers work
2784 better than they would in emulation mode.
2785 It also makes exploits much easier to write.
2787 none Vsyscalls don't work at all. This makes
2788 them quite hard to use for exploits but
2789 might break your system.
2791 vt.cur_default= [VT] Default cursor shape.
2792 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2793 the parameters of the <Esc>[?A;B;Cc escape sequence;
2794 see VGA-softcursor.txt. Default: 2 = underline.
2796 vt.default_blu= [VT]
2797 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2798 Change the default blue palette of the console.
2799 This is a 16-member array composed of values
2802 vt.default_grn= [VT]
2803 Format: <green0>,<green1>,<green2>,...,<green15>
2804 Change the default green palette of the console.
2805 This is a 16-member array composed of values
2808 vt.default_red= [VT]
2809 Format: <red0>,<red1>,<red2>,...,<red15>
2810 Change the default red palette of the console.
2811 This is a 16-member array composed of values
2817 Set system-wide default UTF-8 mode for all tty's.
2818 Default is 1, i.e. UTF-8 mode is enabled for all
2819 newly opened terminals.
2821 vt.global_cursor_default=
2824 Set system-wide default for whether a cursor
2825 is shown on new VTs. Default is -1,
2826 i.e. cursors will be created by default unless
2827 overridden by individual drivers. 0 will hide
2828 cursors, 1 will display them.
2830 watchdog timers [HW,WDT] For information on watchdog timers,
2831 see Documentation/watchdog/watchdog-parameters.txt
2832 or other driver-specific files in the
2833 Documentation/watchdog/ directory.
2835 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2836 default x2apic cluster mode on platforms
2839 x86_mrst_timer= [X86-32,APBT]
2840 Choose timer option for x86 Moorestown MID platform.
2841 Two valid options are apbt timer only and lapic timer
2842 plus one apbt timer for broadcast timer.
2843 x86_mrst_timer=apbt_only | lapic_and_apbt
2845 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2846 xd_geo= See header of drivers/block/xd.c.
2848 xen_emul_unplug= [HW,X86,XEN]
2849 Unplug Xen emulated devices
2850 Format: [unplug0,][unplug1]
2851 ide-disks -- unplug primary master IDE devices
2852 aux-ide-disks -- unplug non-primary-master IDE devices
2853 nics -- unplug network devices
2854 all -- unplug all emulated devices (NICs and IDE disks)
2855 unnecessary -- unplugging emulated devices is
2856 unnecessary even if the host did not respond to
2858 never -- do not unplug even if version check succeeds
2860 xirc2ps_cs= [NET,PCMCIA]
2862 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2864 ______________________________________________________________________
2868 Add more DRM drivers.
git.openpandora.org / pandora-kernel.git / blob