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 1: only for 32-bit processes
319 2: 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,X86-84]
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
506 cmo_free_hint= [PPC] Format: { yes | no }
507 Specify whether pages are marked as being inactive
508 when they are freed. This is used in CMO environments
509 to determine OS memory pressure for page stealing by
513 code_bytes [X86] How many bytes of object code to print
518 com20020= [HW,NET] ARCnet - COM20020 chipset
520 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
522 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
526 ARCnet - COM90xx chipset (memory-mapped buffers)
527 Format: <io>[,<irq>[,<memstart>]]
529 condev= [HW,S390] console device
532 console= [KNL] Output console device and options.
534 tty<n> Use the virtual console device <n>.
538 Use the specified serial port. The options are of
539 the form "bbbbpnf", where "bbbb" is the baud rate,
540 "p" is parity ("n", "o", or "e"), "n" is number of
541 bits, and "f" is flow control ("r" for RTS or
542 omit it). Default is "9600n8".
544 See Documentation/serial-console.txt for more
546 Documentation/networking/netconsole.txt for an
549 uart[8250],io,<addr>[,options]
550 uart[8250],mmio,<addr>[,options]
551 Start an early, polled-mode console on the 8250/16550
552 UART at the specified I/O port or MMIO address,
553 switching to the matching ttyS device later. The
554 options are the same as for ttyS, above.
556 If the device connected to the port is not a TTY but a braille
557 device, prepend "brl," before the device type, for instance
559 For now, only VisioBraille is supported.
561 consoleblank= [KNL] The console blank (screen saver) timeout in
562 seconds. Defaults to 10*60 = 10mins. A value of 0
563 disables the blank timer.
566 [KNL] Change the default value for
567 /proc/<pid>/coredump_filter.
568 See also Documentation/filesystems/proc.txt.
570 cpuidle.off=1 [CPU_IDLE]
571 disable the cpuidle sub-system
573 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
575 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
577 crashkernel=size[KMG][@offset[KMG]]
578 [KNL] Using kexec, Linux can switch to a 'crash kernel'
579 upon panic. This parameter reserves the physical
580 memory region [offset, offset + size] for that kernel
581 image. If '@offset' is omitted, then a suitable offset
582 is selected automatically. Check
583 Documentation/kdump/kdump.txt for further details.
585 crashkernel=range1:size1[,range2:size2,...][@offset]
586 [KNL] Same as above, but depends on the memory
587 in the running system. The syntax of range is
588 start-[end] where start and end are both
589 a memory unit (amount[KMG]). See also
590 Documentation/kdump/kdump.txt for an example.
595 cs89x0_media= [HW,NET]
596 Format: { rj45 | aui | bnc }
599 See header of drivers/s390/block/dasd_devmap.c.
601 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
602 (one device per port)
603 Format: <port#>,<type>
604 See also Documentation/input/joystick-parport.txt
606 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
607 time. See Documentation/dynamic-debug-howto.txt for
610 debug [KNL] Enable kernel debugging (events log level).
613 [KNL] verbose self-tests
615 Print debugging info while doing the locking API
617 We default to 0 (no extra messages), setting it to
618 1 will print _a lot_ more information - normally
619 only useful to kernel developers.
621 debug_objects [KNL] Enable object debugging
624 [KNL] Disable object debugging
626 debugpat [X86] Enable PAT debugging
628 decnet.addr= [HW,NET]
629 Format: <area>[,<node>]
630 See also Documentation/networking/decnet.txt.
633 [same as hugepagesz=] The size of the default
634 HugeTLB page size. This is the size represented by
635 the legacy /proc/ hugepages APIs, used for SHM, and
636 default size when mounting hugetlbfs filesystems.
637 Defaults to the default architecture's huge page size
641 Set number of hash buckets for dentry cache.
644 IO parameters + enable/disable command.
646 digiepca= [HW,SERIAL]
647 See drivers/char/README.epca and
648 Documentation/serial/digiepca.txt.
651 See Documentation/networking/ipv6.txt.
653 disable_ddw [PPC/PSERIES]
654 Disable Dynamic DMA Window support. Use this if
655 to workaround buggy firmware.
658 See Documentation/networking/ipv6.txt.
660 disable_mtrr_cleanup [X86]
661 The kernel tries to adjust MTRR layout from continuous
662 to discrete, to make X server driver able to add WB
663 entry later. This parameter disables that.
665 disable_mtrr_trim [X86, Intel and AMD only]
666 By default the kernel will trim any uncacheable
667 memory out of your available memory pool based on
668 MTRR settings. This parameter disables that behavior,
669 possibly causing your machine to run very slowly.
671 disable_timer_pin_1 [X86]
672 Disable PIN 1 of APIC timer
673 Can be useful to work around chipset bugs.
675 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
676 this option disables the debugging code at boot.
678 dma_debug_entries=<number>
679 This option allows to tune the number of preallocated
680 entries for DMA-API debugging code. One entry is
681 required per DMA-API allocation. Use this if the
682 DMA-API debugging code disables itself because the
683 architectural default is too low.
685 dma_debug_driver=<driver_name>
686 With this option the DMA-API debugging driver
687 filter feature can be enabled at boot time. Just
688 pass the driver to filter for as the parameter.
689 The filter can be disabled or changed to another
690 driver later using sysfs.
694 earlycon= [KNL] Output early console device and options.
695 uart[8250],io,<addr>[,options]
696 uart[8250],mmio,<addr>[,options]
697 uart[8250],mmio32,<addr>[,options]
698 Start an early, polled-mode console on the 8250/16550
699 UART at the specified I/O port or MMIO address.
700 MMIO inter-register address stride is either 8-bit
701 (mmio) or 32-bit (mmio32).
702 The options are the same as for ttyS, above.
704 earlyprintk= [X86,SH,BLACKFIN]
706 earlyprintk=serial[,ttySn[,baudrate]]
707 earlyprintk=ttySn[,baudrate]
708 earlyprintk=dbgp[debugController#]
710 Append ",keep" to not disable it when the real console
713 Only vga or serial or usb debug port at a time.
715 Currently only ttyS0 and ttyS1 are supported.
717 Interaction with the standard serial driver is not
720 The VGA output is eventually overwritten by the real
723 ekgdboc= [X86,KGDB] Allow early kernel console debugging
726 This is designed to be used in conjunction with
727 the boot argument: earlyprintk=vga
730 Format: {"off" | "on" | "skip[mbr]"}
732 eisa_irq_edge= [PARISC,HW]
733 See header of drivers/parisc/eisa.c.
736 See comment before function elanfreq_setup() in
737 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
740 Format: {"cfq" | "deadline" | "noop"}
741 See Documentation/block/cfq-iosched.txt and
742 Documentation/block/deadline-iosched.txt for details.
744 elfcorehdr= [IA-64,PPC,SH,X86]
745 Specifies physical address of start of kernel core
746 image elf header. Generally kexec loader will
747 pass this option to capture kernel.
748 See Documentation/kdump/kdump.txt for details.
750 enable_mtrr_cleanup [X86]
751 The kernel tries to adjust MTRR layout from continuous
752 to discrete, to make X server driver able to add WB
753 entry later. This parameter enables that.
755 enable_timer_pin_1 [X86]
756 Enable PIN 1 of APIC timer
757 Can be useful to work around chipset bugs
758 (in particular on some ATI chipsets).
759 The kernel tries to set a reasonable default.
761 enforcing [SELINUX] Set initial enforcing status.
763 See security/selinux/Kconfig help text.
764 0 -- permissive (log only, no denials).
765 1 -- enforcing (deny and log).
767 Value can be changed at runtime via /selinux/enforce.
770 Disable Error Record Serialization Table (ERST)
773 ether= [HW,NET] Ethernet cards parameters
774 This option is obsoleted by the "netdev=" option, which
775 has equivalent usage. See its documentation for details.
779 Permit 'security.evm' to be updated regardless of
780 current integrity status.
784 fail_make_request=[KNL]
785 General fault injection mechanism.
786 Format: <interval>,<probability>,<space>,<times>
787 See also Documentation/fault-injection/.
790 See Documentation/blockdev/floppy.txt.
792 force_pal_cache_flush
793 [IA-64] Avoid check_sal_cache_flush which may hang on
794 buggy SAL_CACHE_FLUSH implementations. Using this
795 parameter will force ia64_sal_cache_flush to call
796 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
799 [FTRACE] will set and start the specified tracer
800 as early as possible in order to facilitate early
803 ftrace_dump_on_oops[=orig_cpu]
804 [FTRACE] will dump the trace buffers on oops.
805 If no parameter is passed, ftrace will dump
806 buffers of all CPUs, but if you pass orig_cpu, it will
807 dump only the buffer of the CPU that triggered the
810 ftrace_filter=[function-list]
811 [FTRACE] Limit the functions traced by the function
812 tracer at boot up. function-list is a comma separated
813 list of functions. This list can be changed at run
814 time by the set_ftrace_filter file in the debugfs
817 ftrace_notrace=[function-list]
818 [FTRACE] Do not trace the functions specified in
819 function-list. This list can be changed at run time
820 by the set_ftrace_notrace file in the debugfs
823 ftrace_graph_filter=[function-list]
824 [FTRACE] Limit the top level callers functions traced
825 by the function graph tracer at boot up.
826 function-list is a comma separated list of functions
827 that can be changed at run time by the
828 set_graph_function file in the debugfs tracing directory.
831 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
832 support via parallel port (up to 5 devices per port)
833 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
834 See also Documentation/input/joystick-parport.txt
838 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
842 gcov_persist= [GCOV] When non-zero (default), profiling data for
843 kernel modules is saved and remains accessible via
844 debugfs, even when the module is unloaded/reloaded.
845 When zero, profiling data is discarded and associated
846 debugfs files are removed at module unload time.
848 gpt [EFI] Forces disk with valid GPT signature but
849 invalid Protective MBR to be treated as GPT.
851 hashdist= [KNL,NUMA] Large hashes allocated during boot
852 are distributed across NUMA nodes. Defaults on
853 for 64-bit NUMA, off otherwise.
854 Format: 0 | 1 (for off | on)
856 hcl= [IA-64] SGI's Hardware Graph compatibility layer
858 hd= [EIDE] (E)IDE hard drive subsystem geometry
859 Format: <cyl>,<head>,<sect>
862 Disable Hardware Error Source Table (HEST) support;
863 corresponding firmware-first mode error processing
864 logic will be disabled.
866 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
867 size of <nn>. This works even on boxes that have no
868 highmem otherwise. This also works to reduce highmem
869 size on bigger boxes.
871 highres= [KNL] Enable/disable high resolution timer mode.
872 Valid parameters: "on", "off"
876 See Documentation/isdn/README.HiSax.
880 hpet= [X86-32,HPET] option to control HPET usage
881 Format: { enable (default) | disable | force |
883 disable: disable HPET and use PIT instead
884 force: allow force enabled of undocumented chips (ICH4,
886 verbose: show contents of HPET registers during setup
888 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
889 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
890 On x86-64 and powerpc, this option can be specified
891 multiple times interleaved with hugepages= to reserve
892 huge pages of different sizes. Valid pages sizes on
893 x86-64 are 2M (when the CPU supports "pse") and 1G
894 (when the CPU supports the "pdpe1gb" cpuinfo flag)
895 Note that 1GB pages can only be allocated at boot time
896 using hugepages= and not freed afterwards.
898 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
899 terminal devices. Valid values: 0..8
900 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
901 If specified, z/VM IUCV HVC accepts connections
902 from listed z/VM user IDs only.
905 Do not unregister boot console at start. This is only
906 useful for debugging when something happens in the window
907 between unregistering the boot console and initializing
910 i2c_bus= [HW] Override the default board specific I2C bus speed
911 or register an additional I2C bus that is not
912 registered from board initialization code.
916 i8042.debug [HW] Toggle i8042 debug mode
917 i8042.direct [HW] Put keyboard port into non-translated mode
918 i8042.dumbkbd [HW] Pretend that controller can only read data from
919 keyboard and cannot control its state
920 (Don't attempt to blink the leds)
921 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
922 i8042.nokbd [HW] Don't check/create keyboard port
923 i8042.noloop [HW] Disable the AUX Loopback command while probing
925 i8042.nomux [HW] Don't check presence of an active multiplexing
927 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
929 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
930 i8042.reset [HW] Reset the controller during init and cleanup
931 i8042.unlock [HW] Unlock (ignore) the keylock
935 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
936 indicates that the driver is running on unsupported
938 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
939 does not match list of supported models.
941 [HW] Report power status in /proc/i8k
942 (disabled by default)
943 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
947 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
949 ide-core.nodma= [HW] (E)IDE subsystem
950 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
951 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
952 .cdrom .chs .ignore_cable are additional options
953 See Documentation/ide/ide.txt.
955 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
956 Claim all unknown PCI IDE storage controllers.
959 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
960 Poll forces a polling idle loop that can slightly
961 improve the performance of waking up a idle CPU, but
962 will use a lot of power and make the system run hot.
964 idle=mwait: On systems which support MONITOR/MWAIT but
965 the kernel chose to not use it because it doesn't save
966 as much power as a normal idle loop, use the
967 MONITOR/MWAIT idle loop anyways. Performance should be
968 the same as idle=poll.
969 idle=halt: Halt is forced to be used for CPU idle.
970 In such case C2/C3 won't be used again.
971 idle=nomwait: Disable mwait for CPU C-states
973 ignore_loglevel [KNL]
974 Ignore loglevel setting - this will print /all/
975 kernel messages to the console. Useful for debugging.
978 Set number of hash buckets for inode cache.
981 Format: { "0" | "1" }
982 0 -- integrity auditing messages. (Default)
983 1 -- enable informational integrity auditing messages.
986 Format: { "sha1" | "md5" }
990 Load a policy which meets the needs of the Trusted
991 Computing Base. This means IMA will measure all
992 programs exec'd, files mmap'd for exec, and all files
993 opened for read by uid=0.
997 Run specified binary instead of /sbin/init as init
1000 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1001 for working out where the kernel is dying during
1004 initrd= [BOOT] Specify the location of the initial ramdisk
1006 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1009 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1011 Enable intel iommu driver.
1013 Disable intel iommu driver.
1014 igfx_off [Default Off]
1015 By default, gfx is mapped as normal device. If a gfx
1016 device has a dedicated DMAR unit, the DMAR unit is
1017 bypassed by not enabling DMAR with this option. In
1018 this case, gfx device will use physical address for
1021 With this option iommu will not optimize to look
1022 for io virtual address below 32-bit forcing dual
1023 address cycle on pci bus for cards supporting greater
1024 than 32-bit addressing. The default is to look
1025 for translation below 32-bit and if not available
1026 then look in the higher range.
1027 strict [Default Off]
1028 With this option on every unmap_single operation will
1029 result in a hardware IOTLB flush operation as opposed
1030 to batching them for performance.
1031 sp_off [Default Off]
1032 By default, super page will be supported if Intel IOMMU
1033 has the capability. With this option, super page will
1035 intremap= [X86-64, Intel-IOMMU]
1036 on enable Interrupt Remapping (default)
1037 off disable Interrupt Remapping
1038 nosid disable Source ID checking
1040 BIOS x2APIC opt-out request will be ignored
1044 iomem= Disable strict checking of access to MMIO memory
1045 strict regions from userspace.
1061 io7= [HW] IO7 for Marvel based alpha systems
1062 See comment before marvel_specify_io7 in
1063 arch/alpha/kernel/core_marvel.c.
1065 io_delay= [X86] I/O delay method
1067 Standard port 0x80 based delay
1069 Alternate port 0xed based delay (needed on some systems)
1071 Simple two microseconds delay
1076 See Documentation/filesystems/nfs/nfsroot.txt.
1078 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1079 See comment before ip2_setup() in
1080 drivers/char/ip2/ip2base.c.
1083 When an interrupt is not handled search all handlers
1084 for it. Intended to get systems with badly broken
1088 When an interrupt is not handled search all handlers
1089 for it. Also check all handlers each timer
1090 interrupt. Intended to get systems with badly broken
1094 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1096 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1098 <cpu number>,...,<cpu number>
1100 <cpu number>-<cpu number>
1101 (must be a positive range in ascending order)
1103 <cpu number>,...,<cpu number>-<cpu number>
1105 This option can be used to specify one or more CPUs
1106 to isolate from the general SMP balancing and scheduling
1107 algorithms. You can move a process onto or off an
1108 "isolated" CPU via the CPU affinity syscalls or cpuset.
1109 <cpu number> begins at 0 and the maximum value is
1110 "number of CPUs in system - 1".
1112 This option is the preferred way to isolate CPUs. The
1113 alternative -- manually setting the CPU mask of all
1114 tasks in the system -- can cause problems and
1115 suboptimal load balancer performance.
1119 js= [HW,JOY] Analog joystick
1120 See Documentation/input/joystick.txt.
1124 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1125 specifies the amount of memory usable by the kernel
1126 for non-movable allocations. The requested amount is
1127 spread evenly throughout all nodes in the system. The
1128 remaining memory in each node is used for Movable
1129 pages. In the event, a node is too small to have both
1130 kernelcore and Movable pages, kernelcore pages will
1131 take priority and other nodes will have a larger number
1132 of kernelcore pages. The Movable zone is used for the
1133 allocation of pages that may be reclaimed or moved
1134 by the page migration subsystem. This means that
1135 HugeTLB pages may not be allocated from this zone.
1136 Note that allocations like PTEs-from-HighMem still
1137 use the HighMem zone if it exists, and the Normal
1138 zone if it does not.
1140 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1141 Format: <Controller#>[,poll interval]
1142 The controller # is the number of the ehci usb debug
1143 port as it is probed via PCI. The poll interval is
1144 optional and is the number seconds in between
1145 each poll cycle to the debug port in case you need
1146 the functionality for interrupting the kernel with
1147 gdb or control-c on the dbgp connection. When
1148 not using this parameter you use sysrq-g to break into
1149 the kernel debugger.
1151 kgdboc= [KGDB,HW] kgdb over consoles.
1152 Requires a tty driver that supports console polling,
1153 or a supported polling keyboard driver (non-usb).
1154 Serial only format: <serial_device>[,baud]
1155 keyboard only format: kbd
1156 keyboard and serial format: kbd,<serial_device>[,baud]
1157 Optional Kernel mode setting:
1158 kms, kbd format: kms,kbd
1159 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1161 kgdbwait [KGDB] Stop kernel execution and enter the
1162 kernel debugger at the earliest opportunity.
1164 kmac= [MIPS] korina ethernet MAC address.
1165 Configure the RouterBoard 532 series on-chip
1166 Ethernet adapter MAC address.
1168 kmemleak= [KNL] Boot-time kmemleak enable/disable
1169 Valid arguments: on, off
1172 kstack=N [X86] Print N words from the kernel stack
1175 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1176 Default is 0 (don't ignore, but inject #GP)
1178 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1179 Default is 1 (enabled)
1181 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1185 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1186 Default is 1 (enabled)
1188 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1190 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1192 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1193 (virtualized MMU) support on capable Intel chips.
1194 Default is 1 (enabled)
1196 kvm-intel.emulate_invalid_guest_state=
1197 [KVM,Intel] Enable emulation of invalid guest states
1198 Default is 0 (disabled)
1200 kvm-intel.flexpriority=
1201 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1202 Default is 1 (enabled)
1204 kvm-intel.unrestricted_guest=
1205 [KVM,Intel] Disable unrestricted guest feature
1206 (virtualized real and unpaged mode) on capable
1207 Intel chips. Default is 1 (enabled)
1209 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1210 feature (tagged TLBs) on capable Intel chips.
1211 Default is 1 (enabled)
1217 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1220 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1223 libata.dma= [LIBATA] DMA control
1224 libata.dma=0 Disable all PATA and SATA DMA
1225 libata.dma=1 PATA and SATA Disk DMA only
1226 libata.dma=2 ATAPI (CDROM) DMA only
1227 libata.dma=4 Compact Flash DMA only
1228 Combinations also work, so libata.dma=3 enables DMA
1229 for disks and CDROMs, but not CFs.
1231 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1232 libata.ignore_hpa=0 keep BIOS limits (default)
1233 libata.ignore_hpa=1 ignore limits, using full disk
1235 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1239 libata.force= [LIBATA] Force configurations. The format is comma
1240 separated list of "[ID:]VAL" where ID is
1241 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1242 matching port, link or device. Basically, it matches
1243 the ATA ID string printed on console by libata. If
1244 the whole ID part is omitted, the last PORT and DEVICE
1245 values are used. If ID hasn't been specified yet, the
1246 configuration applies to all ports, links and devices.
1248 If only DEVICE is omitted, the parameter applies to
1249 the port and all links and devices behind it. DEVICE
1250 number of 0 either selects the first device or the
1251 first fan-out link behind PMP device. It does not
1252 select the host link. DEVICE number of 15 selects the
1253 host link and device attached to it.
1255 The VAL specifies the configuration to force. As long
1256 as there's no ambiguity shortcut notation is allowed.
1257 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1258 The following configurations can be forced.
1260 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1261 Any ID with matching PORT is used.
1263 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1265 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1266 udma[/][16,25,33,44,66,100,133] notation is also
1269 * [no]ncq: Turn on or off NCQ.
1271 * nohrst, nosrst, norst: suppress hard, soft
1274 * dump_id: dump IDENTIFY data.
1276 If there are multiple matching configurations changing
1277 the same attribute, the last one is used.
1279 memblock=debug [KNL] Enable memblock debug messages.
1281 load_ramdisk= [RAM] List of ramdisks to load from floppy
1282 See Documentation/blockdev/ramdisk.txt.
1284 lockd.nlm_grace_period=P [NFS] Assign grace period.
1287 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1290 lockd.nlm_timeout=T [NFS] Assign timeout value.
1293 lockd.nlm_udpport=M [NFS] Assign UDP port.
1296 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1299 loglevel= All Kernel Messages with a loglevel smaller than the
1300 console loglevel will be printed to the console. It can
1301 also be changed with klogd or other programs. The
1302 loglevels are defined as follows:
1304 0 (KERN_EMERG) system is unusable
1305 1 (KERN_ALERT) action must be taken immediately
1306 2 (KERN_CRIT) critical conditions
1307 3 (KERN_ERR) error conditions
1308 4 (KERN_WARNING) warning conditions
1309 5 (KERN_NOTICE) normal but significant condition
1310 6 (KERN_INFO) informational
1311 7 (KERN_DEBUG) debug-level messages
1313 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1314 in bytes. n must be a power of two. The default
1315 size is set in the kernel config file.
1317 logo.nologo [FB] Disables display of the built-in Linux logo.
1318 This may be used to provide more screen space for
1319 kernel log messages and is useful when debugging
1320 kernel boot problems.
1322 lp=0 [LP] Specify parallel ports to use, e.g,
1323 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1324 lp=reset first parallel port). 'lp=0' disables the
1325 lp=auto printer driver. 'lp=reset' (which can be
1326 specified in addition to the ports) causes
1327 attached printers to be reset. Using
1328 lp=port1,port2,... specifies the parallel ports
1329 to associate lp devices with, starting with
1330 lp0. A port specification may be 'none' to skip
1331 that lp device, or a parport name such as
1332 'parport0'. Specifying 'lp=auto' instead of a
1333 port specification list means that device IDs
1334 from each port should be examined, to see if
1335 an IEEE 1284-compliant printer is attached; if
1336 so, the driver will manage that printer.
1337 See also header of drivers/char/lp.c.
1340 Sets loops_per_jiffy to given constant, thus avoiding
1341 time-consuming boot-time autodetection (up to 250 ms per
1342 CPU). 0 enables autodetection (default). To determine
1343 the correct value for your kernel, boot with normal
1344 autodetection and see what value is printed. Note that
1345 on SMP systems the preset will be applied to all CPUs,
1346 which is likely to cause problems if your CPUs need
1347 significantly divergent settings. An incorrect value
1348 will cause delays in the kernel to be wrong, leading to
1349 unpredictable I/O errors and other breakage. Although
1350 unlikely, in the extreme case this might damage your
1354 Format: <io>,<irq>,<dma>
1356 machvec= [IA-64] Force the use of a particular machine-vector
1357 (machvec) in a generic kernel.
1358 Example: machvec=hpzx1_swiotlb
1360 machtype= [Loongson] Share the same kernel image file between different
1362 Example: machtype=lemote-yeeloong-2f-7inch
1364 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1365 than or equal to this physical address is ignored.
1367 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1368 should make use of. maxcpus=n : n >= 0 limits the
1369 kernel to using 'n' processors. n=0 is a special case,
1370 it is equivalent to "nosmp", which also disables
1373 max_loop= [LOOP] The number of loop block devices that get
1374 (loop.max_loop) unconditionally pre-created at init time. The default
1375 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1376 of statically allocating a predefined number, loop
1377 devices can be requested on-demand with the
1378 /dev/loop-control interface.
1382 mce [X86-32] Machine Check Exception
1384 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1386 md= [HW] RAID subsystems devices and level
1387 See Documentation/md.txt.
1390 Format: <first>,<last>
1391 Specifies range of consoles to be captured by the MDA.
1393 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1394 Amount of memory to be used when the kernel is not able
1395 to see the whole system memory or for test.
1396 [X86-32] Use together with memmap= to avoid physical
1397 address space collisions. Without memmap= PCI devices
1398 could be placed at addresses belonging to unused RAM.
1400 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1404 [KNL,SH] Allow user to override the default size for
1405 per-device physically contiguous DMA buffers.
1407 memmap=exactmap [KNL,X86] Enable setting of an exact
1408 E820 memory map, as specified by the user.
1409 Such memmap=exactmap lines can be constructed based on
1410 BIOS output or other requirements. See the memmap=nn@ss
1413 memmap=nn[KMG]@ss[KMG]
1414 [KNL] Force usage of a specific region of memory
1415 Region of memory to be used, from ss to ss+nn.
1417 memmap=nn[KMG]#ss[KMG]
1418 [KNL,ACPI] Mark specific memory as ACPI data.
1419 Region of memory to be used, from ss to ss+nn.
1421 memmap=nn[KMG]$ss[KMG]
1422 [KNL,ACPI] Mark specific memory as reserved.
1423 Region of memory to be used, from ss to ss+nn.
1424 Example: Exclude memory from 0x18690000-0x1869ffff
1425 memmap=64K$0x18690000
1427 memmap=0x10000$0x18690000
1429 memory_corruption_check=0/1 [X86]
1430 Some BIOSes seem to corrupt the first 64k of
1431 memory when doing things like suspend/resume.
1432 Setting this option will scan the memory
1433 looking for corruption. Enabling this will
1434 both detect corruption and prevent the kernel
1435 from using the memory being corrupted.
1436 However, its intended as a diagnostic tool; if
1437 repeatable BIOS-originated corruption always
1438 affects the same memory, you can use memmap=
1439 to prevent the kernel from using that memory.
1441 memory_corruption_check_size=size [X86]
1442 By default it checks for corruption in the low
1443 64k, making this memory unavailable for normal
1444 use. Use this parameter to scan for
1445 corruption in more or less memory.
1447 memory_corruption_check_period=seconds [X86]
1448 By default it checks for corruption every 60
1449 seconds. Use this parameter to check at some
1450 other rate. 0 disables periodic checking.
1452 memtest= [KNL,X86] Enable memtest
1454 default : 0 <disable>
1455 Specifies the number of memtest passes to be
1456 performed. Each pass selects another test
1457 pattern from a given set of patterns. Memtest
1458 fills the memory with this pattern, validates
1459 memory contents and reserves bad memory
1460 regions that are detected.
1462 meye.*= [HW] Set MotionEye Camera parameters
1463 See Documentation/video4linux/meye.txt.
1465 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1466 Multi-Function General Purpose Timers on AMD Geode
1469 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1470 the BIOS has incorrectly applied a workaround. TinyBIOS
1471 version 0.98 is known to be affected, 0.99 fixes the
1472 problem by letting the user disable the workaround.
1476 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1477 physical address is ignored.
1479 mini2440= [ARM,HW,KNL]
1480 Format:[0..2][b][c][t]
1482 MINI2440 configuration specification:
1483 0 - The attached screen is the 3.5" TFT
1484 1 - The attached screen is the 7" TFT
1485 2 - The VGA Shield is attached (1024x768)
1486 Leaving out the screen size parameter will not load
1487 the TFT driver, and the framebuffer will be left
1489 b - Enable backlight. The TFT backlight pin will be
1490 linked to the kernel VESA blanking code and a GPIO
1491 LED. This parameter is not necessary when using the
1493 c - Enable the s3c camera interface.
1494 t - Reserved for enabling touchscreen support. The
1495 touchscreen support is not enabled in the mainstream
1496 kernel as of 2.6.30, a preliminary port can be found
1497 in the "bleeding edge" mini2440 support kernel at
1498 http://repo.or.cz/w/linux-2.6/mini2440.git
1501 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1502 parameter allows control of the logging verbosity for
1503 the additional memory initialisation checks. A value
1504 of 0 disables mminit logging and a level of 4 will
1505 log everything. Information is printed at KERN_DEBUG
1506 so loglevel=8 may also need to be specified.
1509 [MOUSE] Maximum time between finger touching and
1510 leaving touchpad surface for touch to be considered
1511 a tap and be reported as a left button click (for
1512 touchpads working in absolute mode only).
1514 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1515 reporting absolute coordinates, such as tablets
1516 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1517 reporting absolute coordinates, such as tablets
1519 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1520 is similar to kernelcore except it specifies the
1521 amount of memory used for migratable allocations.
1522 If both kernelcore and movablecore is specified,
1523 then kernelcore will be at *least* the specified
1524 value but may be more. If movablecore on its own
1525 is specified, the administrator must be careful
1526 that the amount of memory usable for all allocations
1529 MTD_Partition= [MTD]
1530 Format: <name>,<region-number>,<size>,<offset>
1532 MTD_Region= [MTD] Format:
1533 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1536 See drivers/mtd/cmdlinepart.c.
1538 multitce=off [PPC] This parameter disables the use of the pSeries
1539 firmware feature for updating multiple TCE entries
1542 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1544 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1546 boundary - index of last SLC block on Flex-OneNAND.
1547 The remaining blocks are configured as MLC blocks.
1548 lock - Configure if Flex-OneNAND boundary should be locked.
1549 Once locked, the boundary cannot be changed.
1550 1 indicates lock status, 0 indicates unlock status.
1553 ARM/S3C2412 JIVE boot control
1555 See arch/arm/mach-s3c2412/mach-jive.c
1557 mtouchusb.raw_coordinates=
1558 [HW] Make the MicroTouch USB driver use raw coordinates
1559 ('y', default) or cooked coordinates ('n')
1561 mtrr_chunk_size=nn[KMG] [X86]
1562 used for mtrr cleanup. It is largest continuous chunk
1563 that could hold holes aka. UC entries.
1565 mtrr_gran_size=nn[KMG] [X86]
1566 Used for mtrr cleanup. It is granularity of mtrr block.
1568 Large value could prevent small alignment from
1571 mtrr_spare_reg_nr=n [X86]
1573 Range: 0,7 : spare reg number
1575 Used for mtrr cleanup. It is spare mtrr entries number.
1576 Set to 2 or more if your graphical card needs more.
1578 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1580 netdev= [NET] Network devices parameters
1581 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1582 Note that mem_start is often overloaded to mean
1583 something different and driver-specific.
1584 This usage is only documented in each driver source
1588 [NETFILTER] Enable connection tracking flow accounting
1589 0 to disable accounting
1590 1 to enable accounting
1593 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1594 See Documentation/filesystems/nfs/nfsroot.txt.
1596 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1597 See Documentation/filesystems/nfs/nfsroot.txt.
1599 nfsrootdebug [NFS] enable nfsroot debugging messages.
1600 See Documentation/filesystems/nfs/nfsroot.txt.
1602 nfs.callback_tcpport=
1603 [NFS] set the TCP port on which the NFSv4 callback
1604 channel should listen.
1607 [NFS] sets the pathname to the program which is used
1608 to update the NFS client cache entries.
1610 nfs.cache_getent_timeout=
1611 [NFS] sets the timeout after which an attempt to
1612 update a cache entry is deemed to have failed.
1614 nfs.idmap_cache_timeout=
1615 [NFS] set the maximum lifetime for idmapper cache
1619 [NFS] enable 64-bit inode numbers.
1620 If zero, the NFS client will fake up a 32-bit inode
1621 number for the readdir() and stat() syscalls instead
1622 of returning the full 64-bit number.
1623 The default is to return 64-bit inode numbers.
1625 nfs.nfs4_disable_idmapping=
1626 [NFSv4] When set, this option disables the NFSv4
1627 idmapper on the client, but only if the mount
1628 is using the 'sec=sys' security flavour. This may
1629 make migration from legacy NFSv2/v3 systems easier
1630 provided that the server has the appropriate support.
1631 The default is to always enable NFSv4 idmapping.
1633 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1634 when a NMI is triggered.
1635 Format: [state][,regs][,debounce][,die]
1637 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1638 Format: [panic,][nopanic,][num]
1640 0 - turn nmi_watchdog off
1641 When panic is specified, panic when an NMI watchdog
1642 timeout occurs (or 'nopanic' to override the opposite
1644 This is useful when you use a panic=... timeout and
1645 need the box quickly up again.
1647 netpoll.carrier_timeout=
1648 [NET] Specifies amount of time (in seconds) that
1649 netpoll should wait for a carrier. By default netpoll
1652 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1653 emulation library even if a 387 maths coprocessor
1657 [HW] Never suspend the console
1658 Disable suspending of consoles during suspend and
1659 hibernate operations. Once disabled, debugging
1660 messages can reach various consoles while the rest
1661 of the system is being put to sleep (ie, while
1662 debugging driver suspend/resume hooks). This may
1663 not work reliably with all consoles, but is known
1664 to work with serial and VGA consoles.
1666 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1667 caches in the slab allocator. Saves per-node memory,
1668 but will impact performance.
1672 noapic [SMP,APIC] Tells the kernel to not make use of any
1673 IOAPICs that may be present in the system.
1675 noautogroup Disable scheduler automatic task group creation.
1677 nobats [PPC] Do not use BATs for mapping kernel lowmem
1678 on "Classic" PPC cores.
1682 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1684 nodelayacct [KNL] Disable per-task delay accounting
1686 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1688 nodsp [SH] Disable hardware DSP at boot time.
1690 noefi [X86] Disable EFI runtime services support.
1695 On X86-32 available only on PAE configured kernels.
1696 noexec=on: enable non-executable mappings (default)
1697 noexec=off: disable non-executable mappings
1700 Disable SMEP (Supervisor Mode Execution Protection)
1701 even if it is supported by processor.
1704 This affects only 32-bit executables.
1705 noexec32=on: enable non-executable mappings (default)
1706 read doesn't imply executable mappings
1707 noexec32=off: disable non-executable mappings
1708 read implies executable mappings
1710 nofpu [SH] Disable hardware FPU at boot time.
1712 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1713 register save and restore. The kernel will only save
1714 legacy floating-point registers on task switch.
1716 noxsave [BUGS=X86] Disables x86 extended register state save
1717 and restore using xsave. The kernel will fallback to
1718 enabling legacy floating-point and sse state.
1720 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1721 wfi(ARM) instruction doesn't work correctly and not to
1722 use it. This is also useful when using JTAG debugger.
1724 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1725 instruction doesn't work correctly and not to
1728 no_file_caps Tells the kernel not to honor file capabilities. The
1729 only way then for a file to be executed with privilege
1730 is to be setuid root or executed by root.
1732 nohalt [IA-64] Tells the kernel not to use the power saving
1733 function PAL_HALT_LIGHT when idle. This increases
1734 power-consumption. On the positive side, it reduces
1735 interrupt wake-up latency, which may improve performance
1736 in certain environments such as networked servers or
1739 nohz= [KNL] Boottime enable/disable dynamic ticks
1740 Valid arguments: on, off
1743 noiotrap [SH] Disables trapped I/O port accesses.
1745 noirqdebug [X86-32] Disables the code which attempts to detect and
1746 disable unhandled interrupt sources.
1748 no_timer_check [X86,APIC] Disables the code which tests for
1749 broken timer IRQ sources.
1751 noisapnp [ISAPNP] Disables ISA PnP code.
1753 noinitrd [RAM] Tells the kernel not to load any configured
1756 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1758 [Deprecated - use intremap=off]
1762 nojitter [IA-64] Disables jitter checking for ITC timers.
1764 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1766 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1769 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1770 steal time is computed, but won't influence scheduler
1773 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1775 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1777 noltlbs [PPC] Do not use large page/tlb entries for kernel
1778 lowmem mapping on PPC40x.
1780 nomca [IA-64] Disable machine check abort handling
1782 nomce [X86-32] Machine Check Exception
1784 nomfgpt [X86-32] Disable Multi-Function General Purpose
1785 Timer usage (for AMD Geode machines).
1787 nopat [X86] Disable PAT (page attribute table extension of
1788 pagetables) support.
1790 norandmaps Don't use address space randomization. Equivalent to
1791 echo 0 > /proc/sys/kernel/randomize_va_space
1793 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1795 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1796 with UP alternatives
1798 noresidual [PPC] Don't use residual data on PReP machines.
1800 nordrand [X86] Disable the direct use of the RDRAND
1801 instruction even if it is supported by the
1802 processor. RDRAND is still available to user
1805 noresume [SWSUSP] Disables resume and restores original swap
1808 no-scroll [VGA] Disables scrollback.
1809 This is required for the Braillex ib80-piezo Braille
1810 reader made by F.H. Papenmeier (Germany).
1814 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1816 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1817 and disable the IO APIC. legacy for "maxcpus=0".
1819 nosoftlockup [KNL] Disable the soft-lockup detector.
1821 nosync [HW,M68K] Disables sync negotiation for all devices.
1823 notsc [BUGS=X86-32] Disable Time Stamp Counter
1825 nousb [USB] Disable the USB subsystem
1827 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1831 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1833 nptcg= [IA-64] Override max number of concurrent global TLB
1834 purges which is reported from either PAL_VM_SUMMARY or
1837 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1838 could support. nr_cpus=n : n >= 1 limits the kernel to
1839 supporting 'n' processors. Later in runtime you can not
1840 use hotplug cpu feature to put more cpu back to online.
1841 just like you compile the kernel NR_CPUS=n
1843 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1845 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1846 one of ['zone', 'node', 'default'] can be specified
1847 This can be set from sysctl after boot.
1848 See Documentation/sysctl/vm.txt for details.
1850 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1851 See Documentation/debugging-via-ohci1394.txt for more
1854 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1855 Rather than timing out after 20 ms if an EC
1856 command is not properly ACKed, override the length
1857 of the timeout. We have interrupts disabled while
1858 waiting for the ACK, so if this is set too high
1859 interrupts *may* be lost!
1861 omap_mux= [OMAP] Override bootloader pin multiplexing.
1862 Format: <mux_mode0.mode_name=value>...
1863 For example, to override I2C bus2:
1864 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1866 oprofile.timer= [HW]
1867 Use timer interrupt instead of performance counters
1869 oprofile.cpu_type= Force an oprofile cpu type
1870 This might be useful if you have an older oprofile
1871 userland or if you want common events.
1872 Format: { arch_perfmon }
1873 arch_perfmon: [X86] Force use of architectural
1874 perfmon on Intel CPUs instead of the
1875 CPU specific event set.
1877 oops=panic Always panic on oopses. Default is to just kill the
1878 process, but there is a small probability of
1879 deadlocking the machine.
1880 This will also cause panics on machine check exceptions.
1881 Useful together with panic=30 to trigger a reboot.
1884 See Documentation/sound/oss/oss-parameters.txt
1886 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1887 timeout > 0: seconds before rebooting
1888 timeout = 0: wait forever
1889 timeout < 0: reboot immediately
1892 parkbd.port= [HW] Parallel port number the keyboard adapter is
1893 connected to, default is 0.
1895 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1896 0 for XT, 1 for AT (default is AT).
1899 parport= [HW,PPT] Specify parallel ports. 0 disables.
1900 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1901 Use 'auto' to force the driver to use any
1902 IRQ/DMA settings detected (the default is to
1903 ignore detected IRQ/DMA settings because of
1904 possible conflicts). You can specify the base
1905 address, IRQ, and DMA settings; IRQ and DMA
1906 should be numbers, or 'auto' (for using detected
1907 settings on that particular port), or 'nofifo'
1908 (to avoid using a FIFO even if it is detected).
1909 Parallel ports are assigned in the order they
1910 are specified on the command line, starting
1913 parport_init_mode= [HW,PPT]
1914 Configure VIA parallel port to operate in
1915 a specific mode. This is necessary on Pegasos
1916 computer where firmware has no options for setting
1917 up parallel port mode and sets it to spp.
1918 Currently this function knows 686a and 8231 chips.
1919 Format: [spp|ps2|epp|ecp|ecpepp]
1922 Halt all CPUs after the first oops has been printed for
1923 the specified number of seconds. This is to be used if
1924 your oopses keep scrolling off the screen.
1929 See header of drivers/block/paride/pcd.c.
1930 See also Documentation/blockdev/paride.txt.
1932 pci=option[,option...] [PCI] various PCI subsystem options:
1933 earlydump [X86] dump PCI config space before the kernel
1935 off [X86] don't probe for the PCI bus
1936 bios [X86-32] force use of PCI BIOS, don't access
1937 the hardware directly. Use this if your machine
1938 has a non-standard PCI host bridge.
1939 nobios [X86-32] disallow use of PCI BIOS, only direct
1940 hardware access methods are allowed. Use this
1941 if you experience crashes upon bootup and you
1942 suspect they are caused by the BIOS.
1943 conf1 [X86] Force use of PCI Configuration
1945 conf2 [X86] Force use of PCI Configuration
1947 noaer [PCIE] If the PCIEAER kernel config parameter is
1948 enabled, this kernel boot option can be used to
1949 disable the use of PCIE advanced error reporting.
1950 nodomains [PCI] Disable support for multiple PCI
1951 root domains (aka PCI segments, in ACPI-speak).
1952 nommconf [X86] Disable use of MMCONFIG for PCI
1954 check_enable_amd_mmconf [X86] check for and enable
1955 properly configured MMIO access to PCI
1956 config space on AMD family 10h CPU
1957 nomsi [MSI] If the PCI_MSI kernel config parameter is
1958 enabled, this kernel boot option can be used to
1959 disable the use of MSI interrupts system-wide.
1960 noioapicquirk [APIC] Disable all boot interrupt quirks.
1961 Safety option to keep boot IRQs enabled. This
1962 should never be necessary.
1963 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1964 primary IO-APIC for bridges that cannot disable
1965 boot IRQs. This fixes a source of spurious IRQs
1966 when the system masks IRQs.
1967 noioapicreroute [APIC] Disable workaround that uses the
1968 boot IRQ equivalent of an IRQ that connects to
1969 a chipset where boot IRQs cannot be disabled.
1970 The opposite of ioapicreroute.
1971 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1972 routing table. These calls are known to be buggy
1973 on several machines and they hang the machine
1974 when used, but on other computers it's the only
1975 way to get the interrupt routing table. Try
1976 this option if the kernel is unable to allocate
1977 IRQs or discover secondary PCI buses on your
1979 rom [X86] Assign address space to expansion ROMs.
1980 Use with caution as certain devices share
1981 address decoders between ROMs and other
1983 norom [X86] Do not assign address space to
1984 expansion ROMs that do not already have
1985 BIOS assigned address ranges.
1986 nobar [X86] Do not assign address space to the
1987 BARs that weren't assigned by the BIOS.
1988 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1989 assigned automatically to PCI devices. You can
1990 make the kernel exclude IRQs of your ISA cards
1992 pirqaddr=0xAAAAA [X86] Specify the physical address
1993 of the PIRQ table (normally generated
1994 by the BIOS) if it is outside the
1995 F0000h-100000h range.
1996 lastbus=N [X86] Scan all buses thru bus #N. Can be
1997 useful if the kernel is unable to find your
1998 secondary buses and you want to tell it
1999 explicitly which ones they are.
2000 assign-busses [X86] Always assign all PCI bus
2001 numbers ourselves, overriding
2002 whatever the firmware may have done.
2003 usepirqmask [X86] Honor the possible IRQ mask stored
2004 in the BIOS $PIR table. This is needed on
2005 some systems with broken BIOSes, notably
2006 some HP Pavilion N5400 and Omnibook XE3
2007 notebooks. This will have no effect if ACPI
2008 IRQ routing is enabled.
2009 noacpi [X86] Do not use ACPI for IRQ routing
2010 or for PCI scanning.
2011 use_crs [X86] Use PCI host bridge window information
2012 from ACPI. On BIOSes from 2008 or later, this
2013 is enabled by default. If you need to use this,
2014 please report a bug.
2015 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2016 If you need to use this, please report a bug.
2017 routeirq Do IRQ routing for all PCI devices.
2018 This is normally done in pci_enable_device(),
2019 so this option is a temporary workaround
2020 for broken drivers that don't call it.
2021 skip_isa_align [X86] do not align io start addr, so can
2022 handle more pci cards
2023 firmware [ARM] Do not re-enumerate the bus but instead
2024 just use the configuration from the
2025 bootloader. This is currently used on
2026 IXP2000 systems where the bus has to be
2027 configured a certain way for adjunct CPUs.
2028 noearly [X86] Don't do any early type 1 scanning.
2029 This might help on some broken boards which
2030 machine check when some devices' config space
2031 is read. But various workarounds are disabled
2032 and some IOMMU drivers will not work.
2033 bfsort Sort PCI devices into breadth-first order.
2034 This sorting is done to get a device
2035 order compatible with older (<= 2.4) kernels.
2036 nobfsort Don't sort PCI devices into breadth-first order.
2037 cbiosize=nn[KMG] The fixed amount of bus space which is
2038 reserved for the CardBus bridge's IO window.
2039 The default value is 256 bytes.
2040 cbmemsize=nn[KMG] The fixed amount of bus space which is
2041 reserved for the CardBus bridge's memory
2042 window. The default value is 64 megabytes.
2045 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2046 Specifies alignment and device to reassign
2047 aligned memory resources.
2048 If <order of align> is not specified,
2049 PAGE_SIZE is used as alignment.
2050 PCI-PCI bridge can be specified, if resource
2051 windows need to be expanded.
2052 ecrc= Enable/disable PCIe ECRC (transaction layer
2053 end-to-end CRC checking).
2054 bios: Use BIOS/firmware settings. This is the
2058 realloc reallocate PCI resources if allocations done by BIOS
2061 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2064 force Enable ASPM even on devices that claim not to support it.
2065 WARNING: Forcing ASPM on may cause system lockups.
2067 pcie_ports= [PCIE] PCIe ports handling:
2068 auto Ask the BIOS whether or not to use native PCIe services
2069 associated with PCIe ports (PME, hot-plug, AER). Use
2070 them only if that is allowed by the BIOS.
2071 native Use native PCIe services associated with PCIe ports
2073 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2076 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2077 nomsi Do not use MSI for native PCIe PME signaling (this makes
2078 all PCIe root ports use INTx for all services).
2080 pcmv= [HW,PCMCIA] BadgePAD 4
2083 See Documentation/blockdev/paride.txt.
2085 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2088 See arch/parisc/kernel/pdc_chassis.c
2090 percpu_alloc= Select which percpu first chunk allocator to use.
2091 Currently supported values are "embed" and "page".
2092 Archs may support subset or none of the selections.
2093 See comments in mm/percpu.c for details on each
2094 allocator. This parameter is primarily for debugging
2095 and performance comparison.
2098 See Documentation/blockdev/paride.txt.
2101 See Documentation/blockdev/paride.txt.
2103 pirq= [SMP,APIC] Manual mp-table setup
2104 See Documentation/x86/i386/IO-APIC.txt.
2106 plip= [PPT,NET] Parallel port network link
2107 Format: { parport<nr> | timid | 0 }
2108 See also Documentation/parport.txt.
2110 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2111 Override pmtimer IOPort with a hex value.
2115 Enable PNP debug messages (depends on the
2116 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2117 via /sys/module/pnp/parameters/debug. We always show
2118 current resource usage; turning this on also shows
2119 possible settings and some assignment information.
2125 { on | off | curr | res | no-curr | no-res }
2128 [ISAPNP] Exclude IRQs for the autoconfiguration
2131 [ISAPNP] Exclude DMAs for the autoconfiguration
2133 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2134 Ranges are in pairs (I/O port base and size).
2137 [ISAPNP] Exclude memory regions for the
2139 Ranges are in pairs (memory base and size).
2141 ports= [IP_VS_FTP] IPVS ftp helper module
2143 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2145 Format: <port>,<port>....
2147 print-fatal-signals=
2148 [KNL] debug: print fatal signals
2150 If enabled, warn about various signal handling
2151 related application anomalies: too many signals,
2152 too many POSIX.1 timers, fatal signals causing a
2155 If you hit the warning due to signal overflow,
2156 you might want to try "ulimit -i unlimited".
2160 printk.time= Show timing data prefixed to each printk message line
2161 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2163 processor.max_cstate= [HW,ACPI]
2164 Limit processor to maximum C-state
2165 max_cstate=9 overrides any DMI blacklist limit.
2167 processor.nocst [HW,ACPI]
2168 Ignore the _CST method to determine C-states,
2169 instead using the legacy FADT method
2171 profile= [KNL] Enable kernel profiling via /proc/profile
2172 Format: [schedule,]<number>
2173 Param: "schedule" - profile schedule points.
2174 Param: <number> - step/bucket size as a power of 2 for
2175 statistical time based profiling.
2176 Param: "sleep" - profile D-state sleeping (millisecs).
2177 Requires CONFIG_SCHEDSTATS
2178 Param: "kvm" - profile VM exits.
2180 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2182 See Documentation/blockdev/ramdisk.txt.
2184 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2185 probe for; one of (bare|imps|exps|lifebook|any).
2186 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2188 psmouse.resetafter= [HW,MOUSE]
2189 Try to reset the device after so many bad packets
2192 [HW,MOUSE] Set desired mouse resolution, in dpi.
2193 psmouse.smartscroll=
2194 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2195 0 = disabled, 1 = enabled (default).
2197 pstore.backend= Specify the name of the pstore backend to use
2200 See Documentation/blockdev/paride.txt.
2203 [KNL] Number of legacy pty's. Overwrites compiled-in
2206 quiet [KNL] Disable most log messages
2211 See Documentation/md.txt.
2213 ramdisk_blocksize= [RAM]
2214 See Documentation/blockdev/ramdisk.txt.
2216 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2217 See Documentation/blockdev/ramdisk.txt.
2219 rcupdate.blimit= [KNL,BOOT]
2220 Set maximum number of finished RCU callbacks to process
2223 rcupdate.qhimark= [KNL,BOOT]
2224 Set threshold of queued
2225 RCU callbacks over which batch limiting is disabled.
2227 rcupdate.qlowmark= [KNL,BOOT]
2228 Set threshold of queued RCU callbacks below which
2229 batch limiting is re-enabled.
2233 Run specified binary instead of /init from the ramdisk,
2234 used for early userspace startup. See initrd.
2236 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2237 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2238 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2241 [KNL, SMP] Set scheduler's default relax_domain_level.
2242 See Documentation/cgroups/cpusets.txt.
2244 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2246 reservetop= [X86-32]
2248 Reserves a hole at the top of the kernel virtual
2253 Set the amount of memory to reserve for BIOS at
2254 the bottom of the address space.
2256 reset_devices [KNL] Force drivers to reset the underlying device
2257 during initialization.
2260 Specify the partition device for software suspend
2262 resume_offset= [SWSUSP]
2263 Specify the offset from the beginning of the partition
2264 given by "resume=" at which the swap header is located,
2265 in <PAGE_SIZE> units (needed only for swap files).
2266 See Documentation/power/swsusp-and-swap-files.txt
2268 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
2269 read the resume files
2271 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
2272 Useful for devices that are detected asynchronously
2273 (e.g. USB and MMC devices).
2275 hibernate= [HIBERNATION]
2276 noresume Don't check if there's a hibernation image
2277 present during boot.
2278 nocompress Don't compress/decompress hibernation images.
2280 retain_initrd [RAM] Keep initrd memory after extraction
2282 rhash_entries= [KNL,NET]
2283 Set number of hash buckets for route cache
2285 riscom8= [HW,SERIAL]
2286 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2288 ro [KNL] Mount root device read-only on boot
2290 root= [KNL] Root filesystem
2291 See name_to_dev_t comment in init/do_mounts.c.
2293 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2294 mount the root filesystem
2296 rootflags= [KNL] Set root filesystem mount option string
2298 rootfstype= [KNL] Set root filesystem type
2300 rootwait [KNL] Wait (indefinitely) for root device to show up.
2301 Useful for devices that are detected asynchronously
2302 (e.g. USB and MMC devices).
2304 rw [KNL] Mount root device read-write on boot
2306 S [KNL] Run init in single mode
2309 See drivers/net/irda/sa1100_ir.c.
2311 sbni= [NET] Granch SBNI12 leased line adapter
2313 sched_debug [KNL] Enables verbose scheduler debug messages.
2315 security= [SECURITY] Choose a security module to enable at boot.
2316 If this boot parameter is not specified, only the first
2317 security module asking for security registration will be
2318 loaded. An invalid security module name will be treated
2319 as if no module has been chosen.
2321 selinux= [SELINUX] Disable or enable SELinux at boot time.
2322 Format: { "0" | "1" }
2323 See security/selinux/Kconfig help text.
2326 Default value is set via kernel config option.
2327 If enabled at boot time, /selinux/disable can be used
2328 later to disable prior to initial policy load.
2330 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2331 Format: { "0" | "1" }
2332 See security/apparmor/Kconfig help text
2335 Default value is set via kernel config option.
2337 serialnumber [BUGS=X86-32]
2340 Maximal number of shapers.
2342 show_msr= [x86] show boot-time MSR settings
2343 Format: { <integer> }
2344 Show boot-time (BIOS-initialized) MSR settings.
2345 The parameter means the number of CPUs to show,
2346 for example 1 means boot CPU only.
2353 slub_debug[=options[,slabs]] [MM, SLUB]
2354 Enabling slub_debug allows one to determine the
2355 culprit if slab objects become corrupted. Enabling
2356 slub_debug can create guard zones around objects and
2357 may poison objects when not in use. Also tracks the
2358 last alloc / free. For more information see
2359 Documentation/vm/slub.txt.
2361 slub_max_order= [MM, SLUB]
2362 Determines the maximum allowed order for slabs.
2363 A high setting may cause OOMs due to memory
2364 fragmentation. For more information see
2365 Documentation/vm/slub.txt.
2367 slub_min_objects= [MM, SLUB]
2368 The minimum number of objects per slab. SLUB will
2369 increase the slab order up to slub_max_order to
2370 generate a sufficiently large slab able to contain
2371 the number of objects indicated. The higher the number
2372 of objects the smaller the overhead of tracking slabs
2373 and the less frequently locks need to be acquired.
2374 For more information see Documentation/vm/slub.txt.
2376 slub_min_order= [MM, SLUB]
2377 Determines the mininum page order for slabs. Must be
2378 lower than slub_max_order.
2379 For more information see Documentation/vm/slub.txt.
2381 slub_nomerge [MM, SLUB]
2382 Disable merging of slabs with similar size. May be
2383 necessary if there is some reason to distinguish
2384 allocs to different slabs. Debug options disable
2385 merging on their own.
2386 For more information see Documentation/vm/slub.txt.
2389 Format: <io1>[,<io2>[,...,<io8>]]
2391 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2392 attempt to substitute SMP alternatives once at boot.
2394 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2395 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2396 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2397 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2398 smsc-ircc2.ircc_irq= [HW] IRQ line
2399 smsc-ircc2.ircc_dma= [HW] DMA channel
2400 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2401 0: Toshiba Satellite 1800 (GP data pin select)
2402 1: Fast pin select (default)
2406 [KNL] Should the soft-lockup detector generate panics.
2409 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2410 See Documentation/laptops/sonypi.txt
2412 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2413 See Documentation/serial/specialix.txt.
2415 spia_io_base= [HW,MTD]
2421 Enabled the stack tracer on boot up.
2425 Set the STI (builtin display/keyboard on the HP-PARISC
2426 machines) console (graphic card) which should be used
2427 as the initial boot-console.
2428 See also comment in drivers/video/console/sticore.c.
2431 See comment in drivers/video/console/sticore.c.
2434 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2436 sunrpc.min_resvport=
2437 sunrpc.max_resvport=
2439 SunRPC servers often require that client requests
2440 originate from a privileged port (i.e. a port in the
2441 range 0 < portnr < 1024).
2442 An administrator who wishes to reserve some of these
2443 ports for other uses may adjust the range that the
2444 kernel's sunrpc client considers to be privileged
2445 using these two parameters to set the minimum and
2446 maximum port values.
2450 Control how the NFS server code allocates CPUs to
2451 service thread pools. Depending on how many NICs
2452 you have and where their interrupts are bound, this
2453 option will affect which CPUs will do NFS serving.
2454 Note: this parameter cannot be changed while the
2455 NFS server is running.
2457 auto the server chooses an appropriate mode
2458 automatically using heuristics
2459 global a single global pool contains all CPUs
2460 percpu one pool for each CPU
2461 pernode one pool for each NUMA node (equivalent
2462 to global on non-NUMA machines)
2464 sunrpc.tcp_slot_table_entries=
2465 sunrpc.udp_slot_table_entries=
2467 Sets the upper limit on the number of simultaneous
2468 RPC calls that can be sent from the client to a
2469 server. Increasing these values may allow you to
2470 improve throughput, but will also increase the
2471 amount of memory reserved for use by the client.
2474 [KNL] Enable accounting of swap in memory resource
2475 controller if no parameter or 1 is given or disable
2476 it if 0 is given (See Documentation/cgroups/memory.txt)
2478 swiotlb= [IA-64] Number of I/O TLB slabs
2482 sysfs.deprecated=0|1 [KNL]
2483 Enable/disable old style sysfs layout for old udev
2484 on older distributions. When this option is enabled
2485 very new udev will not work anymore. When this option
2486 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2487 in older udev will not work anymore.
2488 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2489 the kernel configuration.
2491 sysrq_always_enabled
2493 Ignore sysrq setting - this boot parameter will
2494 neutralize any effect of /proc/sys/kernel/sysrq.
2495 Useful for debugging.
2499 test_suspend= [SUSPEND]
2500 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2501 standby suspend) as the system sleep state to briefly
2502 enter during system startup. The system is woken from
2503 this state using a wakeup-capable RTC alarm.
2505 thash_entries= [KNL,NET]
2506 Set number of hash buckets for TCP connection
2508 thermal.act= [HW,ACPI]
2509 -1: disable all active trip points in all thermal zones
2510 <degrees C>: override all lowest active trip points
2512 thermal.crt= [HW,ACPI]
2513 -1: disable all critical trip points in all thermal zones
2514 <degrees C>: override all critical trip points
2516 thermal.nocrt= [HW,ACPI]
2517 Set to disable actions on ACPI thermal zone
2518 critical and hot trip points.
2520 thermal.off= [HW,ACPI]
2521 1: disable ACPI thermal control
2523 thermal.psv= [HW,ACPI]
2524 -1: disable all passive trip points
2525 <degrees C>: override all passive trip points to this
2528 thermal.tzp= [HW,ACPI]
2529 Specify global default ACPI thermal zone polling rate
2530 <deci-seconds>: poll all this frequency
2531 0: no polling (default)
2534 Force threading of all interrupt handlers except those
2535 marked explicitely IRQF_NO_THREAD.
2539 Specify if the kernel should make use of the cpu
2540 topology information if the hardware supports this.
2541 The scheduler will make use of this information and
2542 e.g. base its process migration decisions on it.
2547 tpm_suspend_pcr=[HW,TPM]
2548 Format: integer pcr id
2549 Specify that at suspend time, the tpm driver
2550 should extend the specified pcr with zeros,
2551 as a workaround for some chips which fail to
2552 flush the last written pcr on TPM_SaveState.
2553 This will guarantee that all the other pcrs
2556 trace_buf_size=nn[KMG]
2557 [FTRACE] will set tracing buffer size.
2559 trace_event=[event-list]
2560 [FTRACE] Set and start specified trace events in order
2561 to facilitate early boot debugging.
2562 See also Documentation/trace/events.txt
2564 tsc= Disable clocksource stability checks for TSC.
2566 [x86] reliable: mark tsc clocksource as reliable, this
2567 disables clocksource verification at runtime, as well
2568 as the stability checks done at bootup. Used to enable
2569 high-resolution timer mode on older hardware, and in
2570 virtualized environment.
2571 [x86] noirqtime: Do not use TSC to do irq accounting.
2572 Used to run time disable IRQ_TIME_ACCOUNTING on any
2573 platforms where RDTSC is slow and this accounting
2576 turbografx.map[2|3]= [HW,JOY]
2577 TurboGraFX parallel port interface
2579 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2580 See also Documentation/input/joystick-parport.txt
2582 udbg-immortal [PPC] When debugging early kernel crashes that
2583 happen after console_init() and before a proper
2584 console driver takes over, this boot options might
2585 help "seeing" what's going on.
2587 uhash_entries= [KNL,NET]
2588 Set number of hash buckets for UDP/UDP-Lite connections
2591 [USB] Ignore overcurrent events (default N).
2592 Some badly-designed motherboards generate lots of
2593 bogus events, for ports that aren't wired to
2594 anything. Set this parameter to avoid log spamming.
2595 Note that genuine overcurrent events won't be
2599 [X86] Cause panic on unknown NMI.
2601 usbcore.authorized_default=
2602 [USB] Default USB device authorization:
2603 (default -1 = authorized except for wireless USB,
2604 0 = not authorized, 1 = authorized)
2606 usbcore.autosuspend=
2607 [USB] The autosuspend time delay (in seconds) used
2608 for newly-detected USB devices (default 2). This
2609 is the time required before an idle device will be
2610 autosuspended. Devices for which the delay is set
2611 to a negative value won't be autosuspended at all.
2613 usbcore.usbfs_snoop=
2614 [USB] Set to log all usbfs traffic (default 0 = off).
2616 usbcore.blinkenlights=
2617 [USB] Set to cycle leds on hubs (default 0 = off).
2619 usbcore.old_scheme_first=
2620 [USB] Start with the old device initialization
2621 scheme (default 0 = off).
2623 usbcore.use_both_schemes=
2624 [USB] Try the other device initialization scheme
2625 if the first one fails (default 1 = enabled).
2627 usbcore.initial_descriptor_timeout=
2628 [USB] Specifies timeout for the initial 64-byte
2629 USB_REQ_GET_DESCRIPTOR request in milliseconds
2630 (default 5000 = 5.0 seconds).
2633 [USBHID] The interval which mice are to be polled at.
2635 usb-storage.delay_use=
2636 [UMS] The delay in seconds before a new device is
2637 scanned for Logical Units (default 5).
2640 [UMS] A list of quirks entries to supplement or
2641 override the built-in unusual_devs list. List
2642 entries are separated by commas. Each entry has
2643 the form VID:PID:Flags where VID and PID are Vendor
2644 and Product ID values (4-digit hex numbers) and
2645 Flags is a set of characters, each corresponding
2646 to a common usb-storage quirk flag as follows:
2647 a = SANE_SENSE (collect more than 18 bytes
2649 b = BAD_SENSE (don't collect more than 18
2650 bytes of sense data);
2651 c = FIX_CAPACITY (decrease the reported
2652 device capacity by one sector);
2653 d = NO_READ_DISC_INFO (don't use
2654 READ_DISC_INFO command);
2655 e = NO_READ_CAPACITY_16 (don't use
2656 READ_CAPACITY_16 command);
2657 h = CAPACITY_HEURISTICS (decrease the
2658 reported device capacity by one
2659 sector if the number is odd);
2660 i = IGNORE_DEVICE (don't bind to this
2662 l = NOT_LOCKABLE (don't try to lock and
2663 unlock ejectable media);
2664 m = MAX_SECTORS_64 (don't transfer more
2665 than 64 sectors = 32 KB at a time);
2666 n = INITIAL_READ10 (force a retry of the
2667 initial READ(10) command);
2668 o = CAPACITY_OK (accept the capacity
2669 reported by the device);
2670 r = IGNORE_RESIDUE (the device reports
2671 bogus residue values);
2672 s = SINGLE_LUN (the device has only one
2674 w = NO_WP_DETECT (don't test whether the
2675 medium is write-protected).
2676 Example: quirks=0419:aaf5:rl,0421:0433:rc
2678 user_debug= [KNL,ARM]
2680 See arch/arm/Kconfig.debug help text.
2681 1 - undefined instruction events
2683 4 - invalid data aborts
2686 Example: user_debug=31
2689 [X86] Flags controlling user PTE allocations.
2691 nohigh = do not allocate PTE pages in
2692 HIGHMEM regardless of setting
2696 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2697 vdso=1: enable VDSO (default)
2698 vdso=0: disable VDSO mapping
2701 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2702 vdso32=1: enable 32-bit VDSO (default)
2703 vdso32=0: disable 32-bit VDSO mapping
2706 vector=percpu: enable percpu vector domain
2708 video= [FB] Frame buffer configuration
2709 See Documentation/fb/modedb.txt.
2711 vga= [BOOT,X86-32] Select a particular video mode
2712 See Documentation/x86/boot.txt and
2713 Documentation/svga.txt.
2714 Use vga=ask for menu.
2715 This is actually a boot loader parameter; the value is
2716 passed to the kernel using a special protocol.
2718 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2719 size of <nn>. This can be used to increase the
2720 minimum size (128MB on x86). It can also be used to
2721 decrease the size and leave more room for directly
2724 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2727 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2730 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2734 Controls the behavior of vsyscalls (i.e. calls to
2735 fixed addresses of 0xffffffffff600x00 from legacy
2736 code). Most statically-linked binaries and older
2737 versions of glibc use these calls. Because these
2738 functions are at fixed addresses, they make nice
2739 targets for exploits that can control RIP.
2741 emulate Vsyscalls turn into traps and are emulated
2744 native [default] Vsyscalls are native syscall
2746 This is a little bit faster than trapping
2747 and makes a few dynamic recompilers work
2748 better than they would in emulation mode.
2749 It also makes exploits much easier to write.
2751 none Vsyscalls don't work at all. This makes
2752 them quite hard to use for exploits but
2753 might break your system.
2755 vt.cur_default= [VT] Default cursor shape.
2756 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2757 the parameters of the <Esc>[?A;B;Cc escape sequence;
2758 see VGA-softcursor.txt. Default: 2 = underline.
2760 vt.default_blu= [VT]
2761 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2762 Change the default blue palette of the console.
2763 This is a 16-member array composed of values
2766 vt.default_grn= [VT]
2767 Format: <green0>,<green1>,<green2>,...,<green15>
2768 Change the default green palette of the console.
2769 This is a 16-member array composed of values
2772 vt.default_red= [VT]
2773 Format: <red0>,<red1>,<red2>,...,<red15>
2774 Change the default red palette of the console.
2775 This is a 16-member array composed of values
2781 Set system-wide default UTF-8 mode for all tty's.
2782 Default is 1, i.e. UTF-8 mode is enabled for all
2783 newly opened terminals.
2785 vt.global_cursor_default=
2788 Set system-wide default for whether a cursor
2789 is shown on new VTs. Default is -1,
2790 i.e. cursors will be created by default unless
2791 overridden by individual drivers. 0 will hide
2792 cursors, 1 will display them.
2794 watchdog timers [HW,WDT] For information on watchdog timers,
2795 see Documentation/watchdog/watchdog-parameters.txt
2796 or other driver-specific files in the
2797 Documentation/watchdog/ directory.
2799 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2800 default x2apic cluster mode on platforms
2803 x86_mrst_timer= [X86-32,APBT]
2804 Choose timer option for x86 Moorestown MID platform.
2805 Two valid options are apbt timer only and lapic timer
2806 plus one apbt timer for broadcast timer.
2807 x86_mrst_timer=apbt_only | lapic_and_apbt
2809 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2810 xd_geo= See header of drivers/block/xd.c.
2812 xen_emul_unplug= [HW,X86,XEN]
2813 Unplug Xen emulated devices
2814 Format: [unplug0,][unplug1]
2815 ide-disks -- unplug primary master IDE devices
2816 aux-ide-disks -- unplug non-primary-master IDE devices
2817 nics -- unplug network devices
2818 all -- unplug all emulated devices (NICs and IDE disks)
2819 unnecessary -- unplugging emulated devices is
2820 unnecessary even if the host did not respond to
2822 never -- do not unplug even if version check succeeds
2824 xirc2ps_cs= [NET,PCMCIA]
2826 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2828 ______________________________________________________________________
2832 Add more DRM drivers.
projects / linux-2.6-microblaze.git / blob