4 The following is a consolidated list of the kernel parameters as implemented
5 (mostly) by the __setup() macro and sorted into English Dictionary order
6 (defined as ignoring all punctuation and sorting digits before letters in a
7 case insensitive manner), and with descriptions where known.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
14 Module parameters for modules that are built into the kernel image
15 are specified on the kernel command line with the module name plus
16 '.' plus parameter name, with '=' and value if appropriate, such as:
18 usbcore.blinkenlights=1
20 Hyphens (dashes) and underscores are equivalent in parameter names, so
21 log_buf_len=1M print-fatal-signals=1
22 can also be entered as
23 log-buf-len=1M print_fatal_signals=1
26 This document may not be entirely up to date and comprehensive. The command
27 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
28 module. Loadable modules, after being loaded into the running kernel, also
29 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
30 parameters may be changed at runtime by the command
31 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
33 The parameters listed below are only valid if certain kernel build options were
34 enabled and if respective hardware is present. The text in square brackets at
35 the beginning of each description states the restrictions within which a
36 parameter is applicable:
38 ACPI ACPI support is enabled.
39 AGP AGP (Accelerated Graphics Port) is enabled.
40 ALSA ALSA sound support is enabled.
41 APIC APIC support is enabled.
42 APM Advanced Power Management support is enabled.
43 AVR32 AVR32 architecture is enabled.
44 AX25 Appropriate AX.25 support is enabled.
45 BLACKFIN Blackfin architecture is enabled.
46 DRM Direct Rendering Management support is enabled.
47 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
48 EFI EFI Partitioning (GPT) is enabled
49 EIDE EIDE/ATAPI support is enabled.
50 FB The frame buffer device is enabled.
51 GCOV GCOV profiling is enabled.
52 HW Appropriate hardware is enabled.
53 IA-64 IA-64 architecture is enabled.
54 IMA Integrity measurement architecture is enabled.
55 IOSCHED More than one I/O scheduler is enabled.
56 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
57 IPV6 IPv6 support is enabled.
58 ISAPNP ISA PnP code is enabled.
59 ISDN Appropriate ISDN support is enabled.
60 JOY Appropriate joystick support is enabled.
61 KGDB Kernel debugger support is enabled.
62 KVM Kernel Virtual Machine support is enabled.
63 LIBATA Libata driver is enabled
64 LP Printer support is enabled.
65 LOOP Loopback device support is enabled.
66 M68k M68k architecture is enabled.
67 These options have more detailed description inside of
68 Documentation/m68k/kernel-options.txt.
69 MCA MCA bus support is enabled.
70 MDA MDA console support is enabled.
71 MOUSE Appropriate mouse support is enabled.
72 MSI Message Signaled Interrupts (PCI).
73 MTD MTD (Memory Technology Device) support is enabled.
74 NET Appropriate network support is enabled.
75 NUMA NUMA support is enabled.
76 GENERIC_TIME The generic timeofday code is enabled.
77 NFS Appropriate NFS support is enabled.
78 OSS OSS sound support is enabled.
79 PV_OPS A paravirtualized kernel is enabled.
80 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
81 PARISC The PA-RISC architecture is enabled.
82 PCI PCI bus support is enabled.
83 PCIE PCI Express support is enabled.
84 PCMCIA The PCMCIA subsystem is enabled.
85 PNP Plug & Play support is enabled.
86 PPC PowerPC architecture is enabled.
87 PPT Parallel port support is enabled.
88 PS2 Appropriate PS/2 support is enabled.
89 RAM RAM disk support is enabled.
90 S390 S390 architecture is enabled.
91 SCSI Appropriate SCSI support is enabled.
92 A lot of drivers has their options described inside of
94 SECURITY Different security models are enabled.
95 SELINUX SELinux support is enabled.
96 SERIAL Serial support is enabled.
97 SH SuperH architecture is enabled.
98 SMP The kernel is an SMP kernel.
99 SPARC Sparc architecture is enabled.
100 SWSUSP Software suspend (hibernation) is enabled.
101 SUSPEND System suspend states are enabled.
102 FTRACE Function tracing enabled.
103 TPM TPM drivers are enabled.
104 TS Appropriate touchscreen support is enabled.
105 UMS USB Mass Storage support is enabled.
106 USB USB support is enabled.
107 USBHID USB Human Interface Device support is enabled.
108 V4L Video For Linux support is enabled.
109 VGA The VGA console has been enabled.
110 VT Virtual terminal support is enabled.
111 WDT Watchdog support is enabled.
112 XT IBM PC/XT MFM hard disk support is enabled.
113 X86-32 X86-32, aka i386 architecture is enabled.
114 X86-64 X86-64 architecture is enabled.
115 More X86-64 boot options can be found in
116 Documentation/x86/x86_64/boot-options.txt .
117 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
119 In addition, the following text indicates that the option:
121 BUGS= Relates to possible processor bugs on the said processor.
122 KNL Is a kernel start-up parameter.
123 BOOT Is a boot loader parameter.
125 Parameters denoted with BOOT are actually interpreted by the boot
126 loader, and have no meaning to the kernel directly.
127 Do not modify the syntax of boot loader parameters without extreme
128 need or coordination with <Documentation/x86/boot.txt>.
130 There are also arch-specific kernel-parameters not documented here.
131 See for example <Documentation/x86/x86_64/boot-options.txt>.
133 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
134 a trailing = on the name of any parameter states that that parameter will
135 be entered as an environment variable, whereas its absence indicates that
136 it will appear as a kernel argument readable via /proc/cmdline by programs
137 running once the system is up.
139 The number of kernel parameters is not limited, but the length of the
140 complete command line (parameters including spaces etc.) is limited to
141 a fixed number of characters. This limit depends on the architecture
142 and is between 256 and 4096 characters. It is defined in the file
143 ./include/asm/setup.h as COMMAND_LINE_SIZE.
147 Advanced Configuration and Power Interface
148 Format: { force | off | strict | noirq | rsdt }
149 force -- enable ACPI if default was off
150 off -- disable ACPI if default was on
151 noirq -- do not use ACPI for IRQ routing
152 strict -- Be less tolerant of platforms that are not
153 strictly ACPI specification compliant.
154 rsdt -- prefer RSDT over (default) XSDT
155 copy_dsdt -- copy DSDT to memory
157 See also Documentation/power/pm.txt, pci=noacpi
159 acpi_apic_instance= [ACPI, IOAPIC]
161 2: use 2nd APIC table, if available
162 1,0: use 1st APIC table
165 acpi_backlight= [HW,ACPI]
166 acpi_backlight=vendor
168 If set to vendor, prefer vendor specific driver
169 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
170 of the ACPI video.ko driver.
172 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
173 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
175 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
176 debug output. Bits in debug_layer correspond to a
177 _COMPONENT in an ACPI source file, e.g.,
178 #define _COMPONENT ACPI_PCI_COMPONENT
179 Bits in debug_level correspond to a level in
180 ACPI_DEBUG_PRINT statements, e.g.,
181 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
182 The debug_level mask defaults to "info". See
183 Documentation/acpi/debug.txt for more information about
184 debug layers and levels.
186 Enable processor driver info messages:
187 acpi.debug_layer=0x20000000
188 Enable PCI/PCI interrupt routing info messages:
189 acpi.debug_layer=0x400000
190 Enable AML "Debug" output, i.e., stores to the Debug
191 object while interpreting AML:
192 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
193 Enable all messages related to ACPI hardware:
194 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
196 Some values produce so much output that the system is
197 unusable. The "log_buf_len" parameter may be useful
198 if you need to capture more output.
200 acpi_display_output= [HW,ACPI]
201 acpi_display_output=vendor
202 acpi_display_output=video
205 acpi_irq_balance [HW,ACPI]
206 ACPI will balance active IRQs
209 acpi_irq_nobalance [HW,ACPI]
210 ACPI will not move active IRQs (default)
213 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
214 Format: <irq>,<irq>...
216 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
218 Format: <irq>,<irq>...
220 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
222 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
223 Format: To spoof as Windows 98: ="Microsoft Windows"
225 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
226 acpi_osi="string1" # add string1 -- only one string
227 acpi_osi="!string2" # remove built-in string2
228 acpi_osi= # disable all strings
231 Override the pmtimer bug detection: force the kernel
232 to assume that this machine's pmtimer latches its value
233 and always returns good values.
235 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
236 Format: { level | edge | high | low }
238 acpi_serialize [HW,ACPI] force serialization of AML methods
240 acpi_skip_timer_override [HW,ACPI]
241 Recognize and ignore IRQ0/pin2 Interrupt Override.
242 For broken nForce2 BIOS resulting in XT-PIC timer.
244 acpi_sleep= [HW,ACPI] Sleep options
245 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
246 old_ordering, s4_nonvs, sci_force_enable }
247 See Documentation/power/video.txt for information on
249 s3_beep is for debugging; it makes the PC's speaker beep
250 as soon as the kernel's real-mode entry point is called.
251 s4_nohwsig prevents ACPI hardware signature from being
252 used during resume from hibernation.
253 old_ordering causes the ACPI 1.0 ordering of the _PTS
254 control method, with respect to putting devices into
255 low power states, to be enforced (the ACPI 2.0 ordering
256 of _PTS is used by default).
257 nonvs prevents the kernel from saving/restoring the
258 ACPI NVS memory during suspend/hibernation and resume.
259 sci_force_enable causes the kernel to set SCI_EN directly
260 on resume from S1/S3 (which is against the ACPI spec,
261 but some broken systems don't work without it).
263 acpi_use_timer_override [HW,ACPI]
264 Use timer override. For some broken Nvidia NF5 boards
265 that require a timer override, but don't have HPET
267 acpi_enforce_resources= [ACPI]
268 { strict | lax | no }
269 Check for resource conflicts between native drivers
270 and ACPI OperationRegions (SystemIO and SystemMemory
271 only). IO ports and memory declared in ACPI might be
272 used by the ACPI subsystem in arbitrary AML code and
273 can interfere with legacy drivers.
274 strict (default): access to resources claimed by ACPI
275 is denied; legacy drivers trying to access reserved
276 resources will fail to bind to device using them.
277 lax: access to resources claimed by ACPI is allowed;
278 legacy drivers trying to access reserved resources
279 will bind successfully but a warning message is logged.
280 no: ACPI OperationRegions are not marked as reserved,
281 no further checks are performed.
284 Format: <io>,<irq>,<dma>,<dma2>,<type>
286 add_efi_memmap [EFI; X86] Include EFI memory map in
287 kernel's map of available physical RAM.
290 See header of drivers/scsi/advansys.c.
292 aedsp16= [HW,OSS] Audio Excel DSP 16
293 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
294 See also header of sound/oss/aedsp16.c.
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/scsi/aha152x.txt.
306 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
309 See Documentation/scsi/aic7xxx.txt.
312 See Documentation/scsi/aic79xx.txt.
315 Allow the default userspace alignment fault handler
316 behaviour to be specified. Bit 0 enables warnings,
317 bit 1 enables fixups, and bit 2 sends a segfault.
319 amd_iommu= [HW,X86-84]
320 Pass parameters to the AMD IOMMU driver in the system.
322 fullflush - enable flushing of IO/TLB entries when
323 they are unmapped. Otherwise they are
324 flushed before they will be reused, which
326 off - do not initialize any AMD IOMMU found in
329 amijoy.map= [HW,JOY] Amiga joystick support
330 Map of devices attached to JOY0DAT and JOY1DAT
332 See also Documentation/kernel/input/joystick.txt
334 analog.map= [HW,JOY] Analog joystick and gamepad support
335 Specifies type or capabilities of an analog joystick
336 connected to one of 16 gameports
337 Format: <type1>,<type2>,..<type16>
340 Power management functions (SPARCstation-4/5 + deriv.)
342 Disable APC CPU standby support. SPARCstation-Fox does
343 not play well with APC CPU idle - disable it if you have
344 APC and your system crashes randomly.
346 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
347 Change the output verbosity whilst booting
348 Format: { quiet (default) | verbose | debug }
349 Change the amount of debugging information output
350 when initialising the APIC and IO-APIC components.
353 See Documentation/networking/ipv6.txt.
355 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
356 Limit apic dumping. The parameter defines the maximal
357 number of local apics being dumped. Also it is possible
358 to set it to "all" by meaning -- no limit here.
359 Format: { 1 (default) | 2 | ... | all }.
360 The parameter valid if only apic=debug or
361 apic=verbose is specified.
362 Example: apic=debug show_lapic=all
364 apm= [APM] Advanced Power Management
365 See header of arch/x86/kernel/apm_32.c.
367 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
368 Format: <io>,<irq>,<nodeID>
372 atarimouse= [HW,MOUSE] Atari Mouse
374 atascsi= [HW,SCSI] Atari SCSI
376 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
377 EzKey and similar keyboards
379 atkbd.reset= [HW] Reset keyboard during initialization
381 atkbd.set= [HW] Select keyboard code set
382 Format: <int> (2 = AT (default), 3 = PS/2)
384 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
387 atkbd.softraw= [HW] Choose between synthetic and real raw mode
388 Format: <bool> (0 = real, 1 = synthetic (default))
390 atkbd.softrepeat= [HW]
391 Use software keyboard repeat
395 baycom_epp= [HW,AX25]
398 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
400 See header of drivers/net/hamradio/baycom_par.c.
402 baycom_ser_fdx= [HW,AX25]
403 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
404 Format: <io>,<irq>,<mode>[,<baud>]
405 See header of drivers/net/hamradio/baycom_ser_fdx.c.
407 baycom_ser_hdx= [HW,AX25]
408 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
409 Format: <io>,<irq>,<mode>
410 See header of drivers/net/hamradio/baycom_ser_hdx.c.
412 boot_delay= Milliseconds to delay each printk during boot.
413 Values larger than 10 seconds (10000) are changed to
417 bootmem_debug [KNL] Enable bootmem allocator debug messages.
419 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
420 bttv.radio= Most important insmod options are available as
422 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
423 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
426 See drivers/scsi/BusLogic.c, comment before function
427 BusLogic_ParseDriverOptions().
429 c101= [NET] Moxa C101 synchronous serial card
431 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
432 Sometimes CPU hardware bugs make them report the cache
433 size incorrectly. The kernel will attempt work arounds
434 to fix known problems, but for some CPUs it is not
435 possible to determine what the correct size should be.
436 This option provides an override for these situations.
439 [SECURITY] Disable capabilities. This would normally
440 be used only if an alternative security model is to be
441 configured. Potentially dangerous and should only be
442 used if you are entirely sure of the consequences.
444 ccw_timeout_log [S390]
445 See Documentation/s390/CommonIO for details.
447 cgroup_disable= [KNL] Disable a particular controller
448 Format: {name of the controller(s) to disable}
449 {Currently supported controllers - "memory"}
451 checkreqprot [SELINUX] Set initial checkreqprot flag value.
452 Format: { "0" | "1" }
453 See security/selinux/Kconfig help text.
454 0 -- check protection applied by kernel (includes
455 any implied execute protection).
456 1 -- check protection requested by application.
457 Default value is set via a kernel config option.
458 Value can be changed at runtime via
459 /selinux/checkreqprot.
462 See Documentation/s390/CommonIO for details.
464 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
466 Forces specified clocksource (if available) to be used
467 when calculating gettimeofday(). If specified
468 clocksource is not available, it defaults to PIT.
469 Format: { pit | tsc | cyclone | pmtmr }
471 clocksource= [GENERIC_TIME] Override the default clocksource
473 Override the default clocksource and use the clocksource
474 with the name specified.
475 Some clocksource names to choose from, depending on
477 [all] jiffies (this is the base, fallback clocksource)
479 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
480 pxa_timer,timer3,32k_counter,timer0_1
482 [X86-32] pit,hpet,tsc,vmi-timer;
483 scx200_hrt on Geode; cyclone on IBM x440
491 clearcpuid=BITNUM [X86]
492 Disable CPUID feature X for the kernel. See
493 arch/x86/include/asm/cpufeature.h for the valid bit
494 numbers. Note the Linux specific bits are not necessarily
495 stable over kernel options, but the vendor specific
497 Also note that user programs calling CPUID directly
498 or using the feature without checking anything
499 will still see it. This just prevents it from
500 being used by the kernel or shown in /proc/cpuinfo.
501 Also note the kernel might malfunction if you disable
504 cmo_free_hint= [PPC] Format: { yes | no }
505 Specify whether pages are marked as being inactive
506 when they are freed. This is used in CMO environments
507 to determine OS memory pressure for page stealing by
511 code_bytes [X86] How many bytes of object code to print
516 com20020= [HW,NET] ARCnet - COM20020 chipset
518 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
520 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
524 ARCnet - COM90xx chipset (memory-mapped buffers)
525 Format: <io>[,<irq>[,<memstart>]]
527 condev= [HW,S390] console device
530 console= [KNL] Output console device and options.
532 tty<n> Use the virtual console device <n>.
536 Use the specified serial port. The options are of
537 the form "bbbbpnf", where "bbbb" is the baud rate,
538 "p" is parity ("n", "o", or "e"), "n" is number of
539 bits, and "f" is flow control ("r" for RTS or
540 omit it). Default is "9600n8".
542 See Documentation/serial-console.txt for more
544 Documentation/networking/netconsole.txt for an
547 uart[8250],io,<addr>[,options]
548 uart[8250],mmio,<addr>[,options]
549 Start an early, polled-mode console on the 8250/16550
550 UART at the specified I/O port or MMIO address,
551 switching to the matching ttyS device later. The
552 options are the same as for ttyS, above.
554 If the device connected to the port is not a TTY but a braille
555 device, prepend "brl," before the device type, for instance
557 For now, only VisioBraille is supported.
559 consoleblank= [KNL] The console blank (screen saver) timeout in
560 seconds. Defaults to 10*60 = 10mins. A value of 0
561 disables the blank timer.
564 [KNL] Change the default value for
565 /proc/<pid>/coredump_filter.
566 See also Documentation/filesystems/proc.txt.
568 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
570 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
572 crashkernel=nn[KMG]@ss[KMG]
573 [KNL] Reserve a chunk of physical memory to
574 hold a kernel to switch to with kexec on panic.
576 crashkernel=range1:size1[,range2:size2,...][@offset]
577 [KNL] Same as above, but depends on the memory
578 in the running system. The syntax of range is
579 start-[end] where start and end are both
580 a memory unit (amount[KMG]). See also
581 Documentation/kdump/kdump.txt for a example.
586 cs89x0_media= [HW,NET]
587 Format: { rj45 | aui | bnc }
590 See header of drivers/s390/block/dasd_devmap.c.
592 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
593 (one device per port)
594 Format: <port#>,<type>
595 See also Documentation/input/joystick-parport.txt
597 debug [KNL] Enable kernel debugging (events log level).
600 [KNL] verbose self-tests
602 Print debugging info while doing the locking API
604 We default to 0 (no extra messages), setting it to
605 1 will print _a lot_ more information - normally
606 only useful to kernel developers.
608 debug_objects [KNL] Enable object debugging
611 [KNL] Disable object debugging
613 debugpat [X86] Enable PAT debugging
615 decnet.addr= [HW,NET]
616 Format: <area>[,<node>]
617 See also Documentation/networking/decnet.txt.
620 [same as hugepagesz=] The size of the default
621 HugeTLB page size. This is the size represented by
622 the legacy /proc/ hugepages APIs, used for SHM, and
623 default size when mounting hugetlbfs filesystems.
624 Defaults to the default architecture's huge page size
628 Set number of hash buckets for dentry cache.
631 IO parameters + enable/disable command.
633 digiepca= [HW,SERIAL]
634 See drivers/char/README.epca and
635 Documentation/serial/digiepca.txt.
638 See Documentation/networking/ipv6.txt.
641 See Documentation/networking/ipv6.txt.
643 disable_mtrr_cleanup [X86]
644 The kernel tries to adjust MTRR layout from continuous
645 to discrete, to make X server driver able to add WB
646 entry later. This parameter disables that.
648 disable_mtrr_trim [X86, Intel and AMD only]
649 By default the kernel will trim any uncacheable
650 memory out of your available memory pool based on
651 MTRR settings. This parameter disables that behavior,
652 possibly causing your machine to run very slowly.
654 disable_timer_pin_1 [X86]
655 Disable PIN 1 of APIC timer
656 Can be useful to work around chipset bugs.
658 dmasound= [HW,OSS] Sound subsystem buffers
660 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
661 this option disables the debugging code at boot.
663 dma_debug_entries=<number>
664 This option allows to tune the number of preallocated
665 entries for DMA-API debugging code. One entry is
666 required per DMA-API allocation. Use this if the
667 DMA-API debugging code disables itself because the
668 architectural default is too low.
670 dma_debug_driver=<driver_name>
671 With this option the DMA-API debugging driver
672 filter feature can be enabled at boot time. Just
673 pass the driver to filter for as the parameter.
674 The filter can be disabled or changed to another
675 driver later using sysfs.
681 dynamic_printk Enables pr_debug()/dev_dbg() calls if
682 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
683 These can also be switched on/off via
684 <debugfs>/dynamic_printk/modules
686 earlycon= [KNL] Output early console device and options.
687 uart[8250],io,<addr>[,options]
688 uart[8250],mmio,<addr>[,options]
689 Start an early, polled-mode console on the 8250/16550
690 UART at the specified I/O port or MMIO address.
691 The options are the same as for ttyS, above.
693 earlyprintk= [X86,SH,BLACKFIN]
695 earlyprintk=serial[,ttySn[,baudrate]]
696 earlyprintk=ttySn[,baudrate]
697 earlyprintk=dbgp[debugController#]
699 Append ",keep" to not disable it when the real console
702 Only vga or serial or usb debug port at a time.
704 Currently only ttyS0 and ttyS1 are supported.
706 Interaction with the standard serial driver is not
709 The VGA output is eventually overwritten by the real
712 ekgdboc= [X86,KGDB] Allow early kernel console debugging
715 This is desgined to be used in conjunction with
716 the boot argument: earlyprintk=vga
721 Format: {"off" | "on" | "skip[mbr]"}
723 eisa_irq_edge= [PARISC,HW]
724 See header of drivers/parisc/eisa.c.
727 See comment before function elanfreq_setup() in
728 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
731 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
732 See Documentation/block/as-iosched.txt and
733 Documentation/block/deadline-iosched.txt for details.
735 elfcorehdr= [IA64,PPC,SH,X86]
736 Specifies physical address of start of kernel core
737 image elf header. Generally kexec loader will
738 pass this option to capture kernel.
739 See Documentation/kdump/kdump.txt for details.
741 enable_mtrr_cleanup [X86]
742 The kernel tries to adjust MTRR layout from continuous
743 to discrete, to make X server driver able to add WB
744 entry later. This parameter enables that.
746 enable_timer_pin_1 [X86]
747 Enable PIN 1 of APIC timer
748 Can be useful to work around chipset bugs
749 (in particular on some ATI chipsets).
750 The kernel tries to set a reasonable default.
752 enforcing [SELINUX] Set initial enforcing status.
754 See security/selinux/Kconfig help text.
755 0 -- permissive (log only, no denials).
756 1 -- enforcing (deny and log).
758 Value can be changed at runtime via /selinux/enforce.
761 Disable Error Record Serialization Table (ERST)
764 ether= [HW,NET] Ethernet cards parameters
765 This option is obsoleted by the "netdev=" option, which
766 has equivalent usage. See its documentation for details.
770 fail_make_request=[KNL]
771 General fault injection mechanism.
772 Format: <interval>,<probability>,<space>,<times>
773 See also /Documentation/fault-injection/.
776 See header of drivers/scsi/fd_mcs.c.
779 See header of drivers/scsi/fdomain.c.
782 See Documentation/blockdev/floppy.txt.
784 force_pal_cache_flush
785 [IA-64] Avoid check_sal_cache_flush which may hang on
786 buggy SAL_CACHE_FLUSH implementations. Using this
787 parameter will force ia64_sal_cache_flush to call
788 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
791 [FTRACE] will set and start the specified tracer
792 as early as possible in order to facilitate early
795 ftrace_dump_on_oops[=orig_cpu]
796 [FTRACE] will dump the trace buffers on oops.
797 If no parameter is passed, ftrace will dump
798 buffers of all CPUs, but if you pass orig_cpu, it will
799 dump only the buffer of the CPU that triggered the
802 ftrace_filter=[function-list]
803 [FTRACE] Limit the functions traced by the function
804 tracer at boot up. function-list is a comma separated
805 list of functions. This list can be changed at run
806 time by the set_ftrace_filter file in the debugfs
809 ftrace_notrace=[function-list]
810 [FTRACE] Do not trace the functions specified in
811 function-list. This list can be changed at run time
812 by the set_ftrace_notrace file in the debugfs
815 ftrace_graph_filter=[function-list]
816 [FTRACE] Limit the top level callers functions traced
817 by the function graph tracer at boot up.
818 function-list is a comma separated list of functions
819 that can be changed at run time by the
820 set_graph_function file in the debugfs tracing directory.
823 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
824 support via parallel port (up to 5 devices per port)
825 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
826 See also Documentation/input/joystick-parport.txt
830 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
834 gcov_persist= [GCOV] When non-zero (default), profiling data for
835 kernel modules is saved and remains accessible via
836 debugfs, even when the module is unloaded/reloaded.
837 When zero, profiling data is discarded and associated
838 debugfs files are removed at module unload time.
841 See header of drivers/scsi/gdth.c.
843 gpt [EFI] Forces disk with valid GPT signature but
844 invalid Protective MBR to be treated as GPT.
848 hashdist= [KNL,NUMA] Large hashes allocated during boot
849 are distributed across NUMA nodes. Defaults on
850 for 64bit NUMA, off otherwise.
851 Format: 0 | 1 (for off | on)
853 hcl= [IA-64] SGI's Hardware Graph compatibility layer
855 hd= [EIDE] (E)IDE hard drive subsystem geometry
856 Format: <cyl>,<head>,<sect>
859 Disable Hardware Error Source Table (HEST) support;
860 corresponding firmware-first mode error processing
861 logic will be disabled.
863 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
864 size of <nn>. This works even on boxes that have no
865 highmem otherwise. This also works to reduce highmem
866 size on bigger boxes.
868 highres= [KNL] Enable/disable high resolution timer mode.
869 Valid parameters: "on", "off"
873 See Documentation/isdn/README.HiSax.
877 hpet= [X86-32,HPET] option to control HPET usage
878 Format: { enable (default) | disable | force |
880 disable: disable HPET and use PIT instead
881 force: allow force enabled of undocumented chips (ICH4,
883 verbose: show contents of HPET registers during setup
885 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
886 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
887 On x86-64 and powerpc, this option can be specified
888 multiple times interleaved with hugepages= to reserve
889 huge pages of different sizes. Valid pages sizes on
890 x86-64 are 2M (when the CPU supports "pse") and 1G
891 (when the CPU supports the "pdpe1gb" cpuinfo flag)
892 Note that 1GB pages can only be allocated at boot time
893 using hugepages= and not freed afterwards.
895 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
896 terminal devices. Valid values: 0..8
897 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
898 If specified, z/VM IUCV HVC accepts connections
899 from listed z/VM user IDs only.
901 i2c_bus= [HW] Override the default board specific I2C bus speed
902 or register an additional I2C bus that is not
903 registered from board initialization code.
907 i8042.debug [HW] Toggle i8042 debug mode
908 i8042.direct [HW] Put keyboard port into non-translated mode
909 i8042.dumbkbd [HW] Pretend that controller can only read data from
910 keyboard and cannot control its state
911 (Don't attempt to blink the leds)
912 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
913 i8042.nokbd [HW] Don't check/create keyboard port
914 i8042.noloop [HW] Disable the AUX Loopback command while probing
916 i8042.nomux [HW] Don't check presence of an active multiplexing
918 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
920 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
922 [HW] Frequency with which keyboard LEDs should blink
923 when kernel panics (default is 0.5 sec)
924 i8042.reset [HW] Reset the controller during init and cleanup
925 i8042.unlock [HW] Unlock (ignore) the keylock
929 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
930 indicates that the driver is running on unsupported
932 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
933 does not match list of supported models.
935 [HW] Report power status in /proc/i8k
936 (disabled by default)
937 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
940 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
941 See Documentation/mca.txt.
944 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
946 ide-core.nodma= [HW] (E)IDE subsystem
947 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
948 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
949 .cdrom .chs .ignore_cable are additional options
950 See Documentation/ide/ide.txt.
952 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
953 Claim all unknown PCI IDE storage controllers.
956 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
957 Poll forces a polling idle loop that can slightly
958 improve the performance of waking up a idle CPU, but
959 will use a lot of power and make the system run hot.
961 idle=mwait: On systems which support MONITOR/MWAIT but
962 the kernel chose to not use it because it doesn't save
963 as much power as a normal idle loop, use the
964 MONITOR/MWAIT idle loop anyways. Performance should be
965 the same as idle=poll.
966 idle=halt: Halt is forced to be used for CPU idle.
967 In such case C2/C3 won't be used again.
968 idle=nomwait: Disable mwait for CPU C-states
970 ignore_loglevel [KNL]
971 Ignore loglevel setting - this will print /all/
972 kernel messages to the console. Useful for debugging.
975 Set number of hash buckets for inode cache.
978 Format: { "0" | "1" }
979 0 -- integrity auditing messages. (Default)
980 1 -- enable informational integrity auditing messages.
983 Format: { "sha1" | "md5" }
987 Load a policy which meets the needs of the Trusted
988 Computing Base. This means IMA will measure all
989 programs exec'd, files mmap'd for exec, and all files
990 opened for read by uid=0.
993 See header of drivers/scsi/in2000.c.
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.
1034 iomem= Disable strict checking of access to MMIO memory
1035 strict regions from userspace.
1051 io7= [HW] IO7 for Marvel based alpha systems
1052 See comment before marvel_specify_io7 in
1053 arch/alpha/kernel/core_marvel.c.
1055 io_delay= [X86] I/O delay method
1057 Standard port 0x80 based delay
1059 Alternate port 0xed based delay (needed on some systems)
1061 Simple two microseconds delay
1066 See Documentation/filesystems/nfs/nfsroot.txt.
1068 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1069 See comment before ip2_setup() in
1070 drivers/char/ip2/ip2base.c.
1072 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
1073 See header of drivers/scsi/ips.c.
1076 When an interrupt is not handled search all handlers
1077 for it. Intended to get systems with badly broken
1081 When an interrupt is not handled search all handlers
1082 for it. Also check all handlers each timer
1083 interrupt. Intended to get systems with badly broken
1087 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1089 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1091 <cpu number>,...,<cpu number>
1093 <cpu number>-<cpu number>
1094 (must be a positive range in ascending order)
1096 <cpu number>,...,<cpu number>-<cpu number>
1098 This option can be used to specify one or more CPUs
1099 to isolate from the general SMP balancing and scheduling
1100 algorithms. You can move a process onto or off an
1101 "isolated" CPU via the CPU affinity syscalls or cpuset.
1102 <cpu number> begins at 0 and the maximum value is
1103 "number of CPUs in system - 1".
1105 This option is the preferred way to isolate CPUs. The
1106 alternative -- manually setting the CPU mask of all
1107 tasks in the system -- can cause problems and
1108 suboptimal load balancer performance.
1112 js= [HW,JOY] Analog joystick
1113 See Documentation/input/joystick.txt.
1117 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1118 specifies the amount of memory usable by the kernel
1119 for non-movable allocations. The requested amount is
1120 spread evenly throughout all nodes in the system. The
1121 remaining memory in each node is used for Movable
1122 pages. In the event, a node is too small to have both
1123 kernelcore and Movable pages, kernelcore pages will
1124 take priority and other nodes will have a larger number
1125 of kernelcore pages. The Movable zone is used for the
1126 allocation of pages that may be reclaimed or moved
1127 by the page migration subsystem. This means that
1128 HugeTLB pages may not be allocated from this zone.
1129 Note that allocations like PTEs-from-HighMem still
1130 use the HighMem zone if it exists, and the Normal
1131 zone if it does not.
1133 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1134 Format: <Controller#>[,poll interval]
1135 The controller # is the number of the ehci usb debug
1136 port as it is probed via PCI. The poll interval is
1137 optional and is the number seconds in between
1138 each poll cycle to the debug port in case you need
1139 the functionality for interrupting the kernel with
1140 gdb or control-c on the dbgp connection. When
1141 not using this parameter you use sysrq-g to break into
1142 the kernel debugger.
1144 kgdboc= [KGDB,HW] kgdb over consoles.
1145 Requires a tty driver that supports console polling,
1146 or a supported polling keyboard driver (non-usb).
1147 Serial only format: <serial_device>[,baud]
1148 keyboard only format: kbd
1149 keyboard and serial format: kbd,<serial_device>[,baud]
1151 kgdbwait [KGDB] Stop kernel execution and enter the
1152 kernel debugger at the earliest opportunity.
1154 kmac= [MIPS] korina ethernet MAC address.
1155 Configure the RouterBoard 532 series on-chip
1156 Ethernet adapter MAC address.
1158 kmemleak= [KNL] Boot-time kmemleak enable/disable
1159 Valid arguments: on, off
1162 kstack=N [X86] Print N words from the kernel stack
1165 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1166 Default is 0 (don't ignore, but inject #GP)
1168 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1169 Default is 1 (enabled)
1171 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1174 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1176 Default is 1 (enabled) if in 64bit or 32bit-PAE mode
1178 kvm-intel.bypass_guest_pf=
1179 [KVM,Intel] Disables bypassing of guest page faults
1180 on Intel chips. Default is 1 (enabled)
1182 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1183 (virtualized MMU) support on capable Intel chips.
1184 Default is 1 (enabled)
1186 kvm-intel.emulate_invalid_guest_state=
1187 [KVM,Intel] Enable emulation of invalid guest states
1188 Default is 0 (disabled)
1190 kvm-intel.flexpriority=
1191 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1192 Default is 1 (enabled)
1194 kvm-intel.unrestricted_guest=
1195 [KVM,Intel] Disable unrestricted guest feature
1196 (virtualized real and unpaged mode) on capable
1197 Intel chips. Default is 1 (enabled)
1199 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1200 feature (tagged TLBs) on capable Intel chips.
1201 Default is 1 (enabled)
1207 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1210 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1213 libata.dma= [LIBATA] DMA control
1214 libata.dma=0 Disable all PATA and SATA DMA
1215 libata.dma=1 PATA and SATA Disk DMA only
1216 libata.dma=2 ATAPI (CDROM) DMA only
1217 libata.dma=4 Compact Flash DMA only
1218 Combinations also work, so libata.dma=3 enables DMA
1219 for disks and CDROMs, but not CFs.
1221 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1222 libata.ignore_hpa=0 keep BIOS limits (default)
1223 libata.ignore_hpa=1 ignore limits, using full disk
1225 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1229 libata.force= [LIBATA] Force configurations. The format is comma
1230 separated list of "[ID:]VAL" where ID is
1231 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1232 matching port, link or device. Basically, it matches
1233 the ATA ID string printed on console by libata. If
1234 the whole ID part is omitted, the last PORT and DEVICE
1235 values are used. If ID hasn't been specified yet, the
1236 configuration applies to all ports, links and devices.
1238 If only DEVICE is omitted, the parameter applies to
1239 the port and all links and devices behind it. DEVICE
1240 number of 0 either selects the first device or the
1241 first fan-out link behind PMP device. It does not
1242 select the host link. DEVICE number of 15 selects the
1243 host link and device attached to it.
1245 The VAL specifies the configuration to force. As long
1246 as there's no ambiguity shortcut notation is allowed.
1247 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1248 The following configurations can be forced.
1250 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1251 Any ID with matching PORT is used.
1253 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1255 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1256 udma[/][16,25,33,44,66,100,133] notation is also
1259 * [no]ncq: Turn on or off NCQ.
1261 * nohrst, nosrst, norst: suppress hard, soft
1264 * dump_id: dump IDENTIFY data.
1266 If there are multiple matching configurations changing
1267 the same attribute, the last one is used.
1269 memblock=debug [KNL] Enable memblock debug messages.
1271 load_ramdisk= [RAM] List of ramdisks to load from floppy
1272 See Documentation/blockdev/ramdisk.txt.
1274 lockd.nlm_grace_period=P [NFS] Assign grace period.
1277 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1280 lockd.nlm_timeout=T [NFS] Assign timeout value.
1283 lockd.nlm_udpport=M [NFS] Assign UDP port.
1286 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1289 loglevel= All Kernel Messages with a loglevel smaller than the
1290 console loglevel will be printed to the console. It can
1291 also be changed with klogd or other programs. The
1292 loglevels are defined as follows:
1294 0 (KERN_EMERG) system is unusable
1295 1 (KERN_ALERT) action must be taken immediately
1296 2 (KERN_CRIT) critical conditions
1297 3 (KERN_ERR) error conditions
1298 4 (KERN_WARNING) warning conditions
1299 5 (KERN_NOTICE) normal but significant condition
1300 6 (KERN_INFO) informational
1301 7 (KERN_DEBUG) debug-level messages
1303 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1304 Format: { n | nk | nM }
1305 n must be a power of two. The default size
1306 is set in the kernel config file.
1308 logo.nologo [FB] Disables display of the built-in Linux logo.
1309 This may be used to provide more screen space for
1310 kernel log messages and is useful when debugging
1311 kernel boot problems.
1313 lp=0 [LP] Specify parallel ports to use, e.g,
1314 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1315 lp=reset first parallel port). 'lp=0' disables the
1316 lp=auto printer driver. 'lp=reset' (which can be
1317 specified in addition to the ports) causes
1318 attached printers to be reset. Using
1319 lp=port1,port2,... specifies the parallel ports
1320 to associate lp devices with, starting with
1321 lp0. A port specification may be 'none' to skip
1322 that lp device, or a parport name such as
1323 'parport0'. Specifying 'lp=auto' instead of a
1324 port specification list means that device IDs
1325 from each port should be examined, to see if
1326 an IEEE 1284-compliant printer is attached; if
1327 so, the driver will manage that printer.
1328 See also header of drivers/char/lp.c.
1331 Sets loops_per_jiffy to given constant, thus avoiding
1332 time-consuming boot-time autodetection (up to 250 ms per
1333 CPU). 0 enables autodetection (default). To determine
1334 the correct value for your kernel, boot with normal
1335 autodetection and see what value is printed. Note that
1336 on SMP systems the preset will be applied to all CPUs,
1337 which is likely to cause problems if your CPUs need
1338 significantly divergent settings. An incorrect value
1339 will cause delays in the kernel to be wrong, leading to
1340 unpredictable I/O errors and other breakage. Although
1341 unlikely, in the extreme case this might damage your
1345 Format: <io>,<irq>,<dma>
1347 mac5380= [HW,SCSI] Format:
1348 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1350 machvec= [IA64] Force the use of a particular machine-vector
1351 (machvec) in a generic kernel.
1352 Example: machvec=hpzx1_swiotlb
1354 machtype= [Loongson] Share the same kernel image file between different
1356 Example: machtype=lemote-yeeloong-2f-7inch
1358 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1359 than or equal to this physical address is ignored.
1361 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1362 should make use of. maxcpus=n : n >= 0 limits the
1363 kernel to using 'n' processors. n=0 is a special case,
1364 it is equivalent to "nosmp", which also disables
1367 max_loop= [LOOP] Maximum number of loopback devices that can
1371 max_luns= [SCSI] Maximum number of LUNs to probe.
1372 Should be between 1 and 2^32-1.
1375 [SCSI] Maximum number of LUNs received.
1376 Should be between 1 and 16384.
1380 mce [X86-32] Machine Check Exception
1382 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1384 md= [HW] RAID subsystems devices and level
1385 See Documentation/md.txt.
1388 Format: <first>,<last>
1389 Specifies range of consoles to be captured by the MDA.
1391 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1392 Amount of memory to be used when the kernel is not able
1393 to see the whole system memory or for test.
1394 [X86-32] Use together with memmap= to avoid physical
1395 address space collisions. Without memmap= PCI devices
1396 could be placed at addresses belonging to unused RAM.
1398 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1402 [KNL,SH] Allow user to override the default size for
1403 per-device physically contiguous DMA buffers.
1405 memmap=exactmap [KNL,X86] Enable setting of an exact
1406 E820 memory map, as specified by the user.
1407 Such memmap=exactmap lines can be constructed based on
1408 BIOS output or other requirements. See the memmap=nn@ss
1411 memmap=nn[KMG]@ss[KMG]
1412 [KNL] Force usage of a specific region of memory
1413 Region of memory to be used, from ss to ss+nn.
1415 memmap=nn[KMG]#ss[KMG]
1416 [KNL,ACPI] Mark specific memory as ACPI data.
1417 Region of memory to be used, from ss to ss+nn.
1419 memmap=nn[KMG]$ss[KMG]
1420 [KNL,ACPI] Mark specific memory as reserved.
1421 Region of memory to be used, from ss to ss+nn.
1422 Example: Exclude memory from 0x18690000-0x1869ffff
1423 memmap=64K$0x18690000
1425 memmap=0x10000$0x18690000
1427 memory_corruption_check=0/1 [X86]
1428 Some BIOSes seem to corrupt the first 64k of
1429 memory when doing things like suspend/resume.
1430 Setting this option will scan the memory
1431 looking for corruption. Enabling this will
1432 both detect corruption and prevent the kernel
1433 from using the memory being corrupted.
1434 However, its intended as a diagnostic tool; if
1435 repeatable BIOS-originated corruption always
1436 affects the same memory, you can use memmap=
1437 to prevent the kernel from using that memory.
1439 memory_corruption_check_size=size [X86]
1440 By default it checks for corruption in the low
1441 64k, making this memory unavailable for normal
1442 use. Use this parameter to scan for
1443 corruption in more or less memory.
1445 memory_corruption_check_period=seconds [X86]
1446 By default it checks for corruption every 60
1447 seconds. Use this parameter to check at some
1448 other rate. 0 disables periodic checking.
1450 memtest= [KNL,X86] Enable memtest
1452 default : 0 <disable>
1453 Specifies the number of memtest passes to be
1454 performed. Each pass selects another test
1455 pattern from a given set of patterns. Memtest
1456 fills the memory with this pattern, validates
1457 memory contents and reserves bad memory
1458 regions that are detected.
1460 meye.*= [HW] Set MotionEye Camera parameters
1461 See Documentation/video4linux/meye.txt.
1463 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1464 Multi-Function General Purpose Timers on AMD Geode
1467 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1468 the BIOS has incorrectly applied a workaround. TinyBIOS
1469 version 0.98 is known to be affected, 0.99 fixes the
1470 problem by letting the user disable the workaround.
1474 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1475 physical address is ignored.
1477 mini2440= [ARM,HW,KNL]
1478 Format:[0..2][b][c][t]
1480 MINI2440 configuration specification:
1481 0 - The attached screen is the 3.5" TFT
1482 1 - The attached screen is the 7" TFT
1483 2 - The VGA Shield is attached (1024x768)
1484 Leaving out the screen size parameter will not load
1485 the TFT driver, and the framebuffer will be left
1487 b - Enable backlight. The TFT backlight pin will be
1488 linked to the kernel VESA blanking code and a GPIO
1489 LED. This parameter is not necessary when using the
1491 c - Enable the s3c camera interface.
1492 t - Reserved for enabling touchscreen support. The
1493 touchscreen support is not enabled in the mainstream
1494 kernel as of 2.6.30, a preliminary port can be found
1495 in the "bleeding edge" mini2440 support kernel at
1496 http://repo.or.cz/w/linux-2.6/mini2440.git
1499 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1500 parameter allows control of the logging verbosity for
1501 the additional memory initialisation checks. A value
1502 of 0 disables mminit logging and a level of 4 will
1503 log everything. Information is printed at KERN_DEBUG
1504 so loglevel=8 may also need to be specified.
1507 [MOUSE] Maximum time between finger touching and
1508 leaving touchpad surface for touch to be considered
1509 a tap and be reported as a left button click (for
1510 touchpads working in absolute mode only).
1512 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1513 reporting absolute coordinates, such as tablets
1514 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1515 reporting absolute coordinates, such as tablets
1517 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1518 is similar to kernelcore except it specifies the
1519 amount of memory used for migratable allocations.
1520 If both kernelcore and movablecore is specified,
1521 then kernelcore will be at *least* the specified
1522 value but may be more. If movablecore on its own
1523 is specified, the administrator must be careful
1524 that the amount of memory usable for all allocations
1530 MTD_Partition= [MTD]
1531 Format: <name>,<region-number>,<size>,<offset>
1533 MTD_Region= [MTD] Format:
1534 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1537 See drivers/mtd/cmdlinepart.c.
1539 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1541 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1543 boundary - index of last SLC block on Flex-OneNAND.
1544 The remaining blocks are configured as MLC blocks.
1545 lock - Configure if Flex-OneNAND boundary should be locked.
1546 Once locked, the boundary cannot be changed.
1547 1 indicates lock status, 0 indicates unlock status.
1550 ARM/S3C2412 JIVE boot control
1552 See arch/arm/mach-s3c2412/mach-jive.c
1554 mtouchusb.raw_coordinates=
1555 [HW] Make the MicroTouch USB driver use raw coordinates
1556 ('y', default) or cooked coordinates ('n')
1558 mtrr_chunk_size=nn[KMG] [X86]
1559 used for mtrr cleanup. It is largest continuous chunk
1560 that could hold holes aka. UC entries.
1562 mtrr_gran_size=nn[KMG] [X86]
1563 Used for mtrr cleanup. It is granularity of mtrr block.
1565 Large value could prevent small alignment from
1568 mtrr_spare_reg_nr=n [X86]
1570 Range: 0,7 : spare reg number
1572 Used for mtrr cleanup. It is spare mtrr entries number.
1573 Set to 2 or more if your graphical card needs more.
1575 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1578 See header of drivers/scsi/NCR_D700.c.
1582 ncr53c400= [HW,SCSI]
1584 ncr53c400a= [HW,SCSI]
1586 ncr53c406a= [HW,SCSI]
1588 ncr53c8xx= [HW,SCSI]
1590 netdev= [NET] Network devices parameters
1591 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1592 Note that mem_start is often overloaded to mean
1593 something different and driver-specific.
1594 This usage is only documented in each driver source
1598 [NETFILTER] Enable connection tracking flow accounting
1599 0 to disable accounting
1600 1 to enable accounting
1601 Default value depends on CONFIG_NF_CT_ACCT that is
1602 going to be removed in 2.6.29.
1605 See Documentation/filesystems/nfs/nfsroot.txt.
1607 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1608 See Documentation/filesystems/nfs/nfsroot.txt.
1610 nfs.callback_tcpport=
1611 [NFS] set the TCP port on which the NFSv4 callback
1612 channel should listen.
1615 [NFS] sets the pathname to the program which is used
1616 to update the NFS client cache entries.
1618 nfs.cache_getent_timeout=
1619 [NFS] sets the timeout after which an attempt to
1620 update a cache entry is deemed to have failed.
1622 nfs.idmap_cache_timeout=
1623 [NFS] set the maximum lifetime for idmapper cache
1627 [NFS] enable 64-bit inode numbers.
1628 If zero, the NFS client will fake up a 32-bit inode
1629 number for the readdir() and stat() syscalls instead
1630 of returning the full 64-bit number.
1631 The default is to return 64-bit inode numbers.
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,][num]
1640 0 - turn nmi_watchdog off
1641 1 - use the IO-APIC timer for the NMI watchdog
1642 2 - use the local APIC for the NMI watchdog using
1643 a performance counter. Note: This will use one
1644 performance counter and the local APIC's performance
1646 When panic is specified, panic when an NMI watchdog
1648 This is useful when you use a panic=... timeout and
1649 need the box quickly up again.
1650 Instead of 1 and 2 it is possible to use the following
1651 symbolic names: lapic and ioapic
1652 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1654 netpoll.carrier_timeout=
1655 [NET] Specifies amount of time (in seconds) that
1656 netpoll should wait for a carrier. By default netpoll
1659 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1660 emulation library even if a 387 maths coprocessor
1664 [HW] Never suspend the console
1665 Disable suspending of consoles during suspend and
1666 hibernate operations. Once disabled, debugging
1667 messages can reach various consoles while the rest
1668 of the system is being put to sleep (ie, while
1669 debugging driver suspend/resume hooks). This may
1670 not work reliably with all consoles, but is known
1671 to work with serial and VGA consoles.
1673 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1674 caches in the slab allocator. Saves per-node memory,
1675 but will impact performance.
1679 noapic [SMP,APIC] Tells the kernel to not make use of any
1680 IOAPICs that may be present in the system.
1682 nobats [PPC] Do not use BATs for mapping kernel lowmem
1683 on "Classic" PPC cores.
1687 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1689 nodelayacct [KNL] Disable per-task delay accounting
1691 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1693 nodsp [SH] Disable hardware DSP at boot time.
1695 noefi [X86] Disable EFI runtime services support.
1700 On X86-32 available only on PAE configured kernels.
1701 noexec=on: enable non-executable mappings (default)
1702 noexec=off: disable non-executable mappings
1705 This affects only 32-bit executables.
1706 noexec32=on: enable non-executable mappings (default)
1707 read doesn't imply executable mappings
1708 noexec32=off: disable non-executable mappings
1709 read implies executable mappings
1711 nofpu [SH] Disable hardware FPU at boot time.
1713 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1714 register save and restore. The kernel will only save
1715 legacy floating-point registers on task switch.
1717 noxsave [BUGS=X86] Disables x86 extended register state save
1718 and restore using xsave. The kernel will fallback to
1719 enabling legacy floating-point and sse state.
1721 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1722 wfi(ARM) instruction doesn't work correctly and not to
1723 use it. This is also useful when using JTAG debugger.
1725 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1726 instruction doesn't work correctly and not to
1729 no_file_caps Tells the kernel not to honor file capabilities. The
1730 only way then for a file to be executed with privilege
1731 is to be setuid root or executed by root.
1733 nohalt [IA-64] Tells the kernel not to use the power saving
1734 function PAL_HALT_LIGHT when idle. This increases
1735 power-consumption. On the positive side, it reduces
1736 interrupt wake-up latency, which may improve performance
1737 in certain environments such as networked servers or
1740 nohz= [KNL] Boottime enable/disable dynamic ticks
1741 Valid arguments: on, off
1744 noiotrap [SH] Disables trapped I/O port accesses.
1746 noirqdebug [X86-32] Disables the code which attempts to detect and
1747 disable unhandled interrupt sources.
1749 no_timer_check [X86,APIC] Disables the code which tests for
1750 broken timer IRQ sources.
1752 noisapnp [ISAPNP] Disables ISA PnP code.
1754 noinitrd [RAM] Tells the kernel not to load any configured
1757 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1762 nojitter [IA64] Disables jitter checking for ITC timers.
1764 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1766 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1768 noltlbs [PPC] Do not use large page/tlb entries for kernel
1769 lowmem mapping on PPC40x.
1771 nomca [IA-64] Disable machine check abort handling
1773 nomce [X86-32] Machine Check Exception
1775 nomfgpt [X86-32] Disable Multi-Function General Purpose
1776 Timer usage (for AMD Geode machines).
1778 nopat [X86] Disable PAT (page attribute table extension of
1779 pagetables) support.
1781 norandmaps Don't use address space randomization. Equivalent to
1782 echo 0 > /proc/sys/kernel/randomize_va_space
1784 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1786 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1787 with UP alternatives
1789 noresidual [PPC] Don't use residual data on PReP machines.
1791 noresume [SWSUSP] Disables resume and restores original swap
1794 no-scroll [VGA] Disables scrollback.
1795 This is required for the Braillex ib80-piezo Braille
1796 reader made by F.H. Papenmeier (Germany).
1800 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1802 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1803 and disable the IO APIC. legacy for "maxcpus=0".
1805 nosoftlockup [KNL] Disable the soft-lockup detector.
1807 noswapaccount [KNL] Disable accounting of swap in memory resource
1808 controller. (See Documentation/cgroups/memory.txt)
1810 nosync [HW,M68K] Disables sync negotiation for all devices.
1812 notsc [BUGS=X86-32] Disable Time Stamp Counter
1814 nousb [USB] Disable the USB subsystem
1818 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1820 nptcg= [IA64] Override max number of concurrent global TLB
1821 purges which is reported from either PAL_VM_SUMMARY or
1824 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1825 could support. nr_cpus=n : n >= 1 limits the kernel to
1826 supporting 'n' processors. Later in runtime you can not
1827 use hotplug cpu feature to put more cpu back to online.
1828 just like you compile the kernel NR_CPUS=n
1830 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1832 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1833 one of ['zone', 'node', 'default'] can be specified
1834 This can be set from sysctl after boot.
1835 See Documentation/sysctl/vm.txt for details.
1837 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1838 See Documentation/debugging-via-ohci1394.txt for more
1841 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1842 Rather than timing out after 20 ms if an EC
1843 command is not properly ACKed, override the length
1844 of the timeout. We have interrupts disabled while
1845 waiting for the ACK, so if this is set too high
1846 interrupts *may* be lost!
1848 omap_mux= [OMAP] Override bootloader pin multiplexing.
1849 Format: <mux_mode0.mode_name=value>...
1850 For example, to override I2C bus2:
1851 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1856 oprofile.timer= [HW]
1857 Use timer interrupt instead of performance counters
1859 oprofile.cpu_type= Force an oprofile cpu type
1860 This might be useful if you have an older oprofile
1861 userland or if you want common events.
1862 Format: { arch_perfmon }
1863 arch_perfmon: [X86] Force use of architectural
1864 perfmon on Intel CPUs instead of the
1865 CPU specific event set.
1867 osst= [HW,SCSI] SCSI Tape Driver
1868 Format: <buffer_size>,<write_threshold>
1869 See also Documentation/scsi/st.txt.
1871 panic= [KNL] Kernel behaviour on panic
1874 parkbd.port= [HW] Parallel port number the keyboard adapter is
1875 connected to, default is 0.
1877 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1878 0 for XT, 1 for AT (default is AT).
1881 parport= [HW,PPT] Specify parallel ports. 0 disables.
1882 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1883 Use 'auto' to force the driver to use any
1884 IRQ/DMA settings detected (the default is to
1885 ignore detected IRQ/DMA settings because of
1886 possible conflicts). You can specify the base
1887 address, IRQ, and DMA settings; IRQ and DMA
1888 should be numbers, or 'auto' (for using detected
1889 settings on that particular port), or 'nofifo'
1890 (to avoid using a FIFO even if it is detected).
1891 Parallel ports are assigned in the order they
1892 are specified on the command line, starting
1895 parport_init_mode= [HW,PPT]
1896 Configure VIA parallel port to operate in
1897 a specific mode. This is necessary on Pegasos
1898 computer where firmware has no options for setting
1899 up parallel port mode and sets it to spp.
1900 Currently this function knows 686a and 8231 chips.
1901 Format: [spp|ps2|epp|ecp|ecpepp]
1903 pas2= [HW,OSS] Format:
1904 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1907 See header of drivers/scsi/pas16.c.
1910 Halt all CPUs after the first oops has been printed for
1911 the specified number of seconds. This is to be used if
1912 your oopses keep scrolling off the screen.
1917 See header of drivers/block/paride/pcd.c.
1918 See also Documentation/blockdev/paride.txt.
1920 pci=option[,option...] [PCI] various PCI subsystem options:
1921 earlydump [X86] dump PCI config space before the kernel
1923 off [X86] don't probe for the PCI bus
1924 bios [X86-32] force use of PCI BIOS, don't access
1925 the hardware directly. Use this if your machine
1926 has a non-standard PCI host bridge.
1927 nobios [X86-32] disallow use of PCI BIOS, only direct
1928 hardware access methods are allowed. Use this
1929 if you experience crashes upon bootup and you
1930 suspect they are caused by the BIOS.
1931 conf1 [X86] Force use of PCI Configuration
1933 conf2 [X86] Force use of PCI Configuration
1935 noaer [PCIE] If the PCIEAER kernel config parameter is
1936 enabled, this kernel boot option can be used to
1937 disable the use of PCIE advanced error reporting.
1938 nodomains [PCI] Disable support for multiple PCI
1939 root domains (aka PCI segments, in ACPI-speak).
1940 nommconf [X86] Disable use of MMCONFIG for PCI
1942 check_enable_amd_mmconf [X86] check for and enable
1943 properly configured MMIO access to PCI
1944 config space on AMD family 10h CPU
1945 nomsi [MSI] If the PCI_MSI kernel config parameter is
1946 enabled, this kernel boot option can be used to
1947 disable the use of MSI interrupts system-wide.
1948 noioapicquirk [APIC] Disable all boot interrupt quirks.
1949 Safety option to keep boot IRQs enabled. This
1950 should never be necessary.
1951 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1952 primary IO-APIC for bridges that cannot disable
1953 boot IRQs. This fixes a source of spurious IRQs
1954 when the system masks IRQs.
1955 noioapicreroute [APIC] Disable workaround that uses the
1956 boot IRQ equivalent of an IRQ that connects to
1957 a chipset where boot IRQs cannot be disabled.
1958 The opposite of ioapicreroute.
1959 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1960 routing table. These calls are known to be buggy
1961 on several machines and they hang the machine
1962 when used, but on other computers it's the only
1963 way to get the interrupt routing table. Try
1964 this option if the kernel is unable to allocate
1965 IRQs or discover secondary PCI buses on your
1967 rom [X86] Assign address space to expansion ROMs.
1968 Use with caution as certain devices share
1969 address decoders between ROMs and other
1971 norom [X86] Do not assign address space to
1972 expansion ROMs that do not already have
1973 BIOS assigned address ranges.
1974 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1975 assigned automatically to PCI devices. You can
1976 make the kernel exclude IRQs of your ISA cards
1978 pirqaddr=0xAAAAA [X86] Specify the physical address
1979 of the PIRQ table (normally generated
1980 by the BIOS) if it is outside the
1981 F0000h-100000h range.
1982 lastbus=N [X86] Scan all buses thru bus #N. Can be
1983 useful if the kernel is unable to find your
1984 secondary buses and you want to tell it
1985 explicitly which ones they are.
1986 assign-busses [X86] Always assign all PCI bus
1987 numbers ourselves, overriding
1988 whatever the firmware may have done.
1989 usepirqmask [X86] Honor the possible IRQ mask stored
1990 in the BIOS $PIR table. This is needed on
1991 some systems with broken BIOSes, notably
1992 some HP Pavilion N5400 and Omnibook XE3
1993 notebooks. This will have no effect if ACPI
1994 IRQ routing is enabled.
1995 noacpi [X86] Do not use ACPI for IRQ routing
1996 or for PCI scanning.
1997 use_crs [X86] Use PCI host bridge window information
1998 from ACPI. On BIOSes from 2008 or later, this
1999 is enabled by default. If you need to use this,
2000 please report a bug.
2001 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2002 If you need to use this, please report a bug.
2003 routeirq Do IRQ routing for all PCI devices.
2004 This is normally done in pci_enable_device(),
2005 so this option is a temporary workaround
2006 for broken drivers that don't call it.
2007 skip_isa_align [X86] do not align io start addr, so can
2008 handle more pci cards
2009 firmware [ARM] Do not re-enumerate the bus but instead
2010 just use the configuration from the
2011 bootloader. This is currently used on
2012 IXP2000 systems where the bus has to be
2013 configured a certain way for adjunct CPUs.
2014 noearly [X86] Don't do any early type 1 scanning.
2015 This might help on some broken boards which
2016 machine check when some devices' config space
2017 is read. But various workarounds are disabled
2018 and some IOMMU drivers will not work.
2019 bfsort Sort PCI devices into breadth-first order.
2020 This sorting is done to get a device
2021 order compatible with older (<= 2.4) kernels.
2022 nobfsort Don't sort PCI devices into breadth-first order.
2023 cbiosize=nn[KMG] The fixed amount of bus space which is
2024 reserved for the CardBus bridge's IO window.
2025 The default value is 256 bytes.
2026 cbmemsize=nn[KMG] The fixed amount of bus space which is
2027 reserved for the CardBus bridge's memory
2028 window. The default value is 64 megabytes.
2031 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2032 Specifies alignment and device to reassign
2033 aligned memory resources.
2034 If <order of align> is not specified,
2035 PAGE_SIZE is used as alignment.
2036 PCI-PCI bridge can be specified, if resource
2037 windows need to be expanded.
2038 ecrc= Enable/disable PCIe ECRC (transaction layer
2039 end-to-end CRC checking).
2040 bios: Use BIOS/firmware settings. This is the
2045 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2048 force Enable ASPM even on devices that claim not to support it.
2049 WARNING: Forcing ASPM on may cause system lockups.
2051 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2052 Format: {auto|force}[,nomsi]
2053 auto Use native PCIe PME signaling if the BIOS allows the
2054 kernel to control PCIe config registers of root ports.
2055 force Use native PCIe PME signaling even if the BIOS refuses
2056 to allow the kernel to control the relevant PCIe config
2058 nomsi Do not use MSI for native PCIe PME signaling (this makes
2059 all PCIe root ports use INTx for everything).
2061 pcmv= [HW,PCMCIA] BadgePAD 4
2064 See Documentation/blockdev/paride.txt.
2066 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2069 See arch/parisc/kernel/pdc_chassis.c
2071 percpu_alloc= Select which percpu first chunk allocator to use.
2072 Currently supported values are "embed" and "page".
2073 Archs may support subset or none of the selections.
2074 See comments in mm/percpu.c for details on each
2075 allocator. This parameter is primarily for debugging
2076 and performance comparison.
2079 See Documentation/blockdev/paride.txt.
2082 See Documentation/blockdev/paride.txt.
2084 pirq= [SMP,APIC] Manual mp-table setup
2085 See Documentation/x86/i386/IO-APIC.txt.
2087 plip= [PPT,NET] Parallel port network link
2088 Format: { parport<nr> | timid | 0 }
2089 See also Documentation/parport.txt.
2091 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2092 Override pmtimer IOPort with a hex value.
2096 Enable PNP debug messages. This depends on the
2097 CONFIG_PNP_DEBUG_MESSAGES option.
2103 { on | off | curr | res | no-curr | no-res }
2106 [ISAPNP] Exclude IRQs for the autoconfiguration
2109 [ISAPNP] Exclude DMAs for the autoconfiguration
2111 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2112 Ranges are in pairs (I/O port base and size).
2115 [ISAPNP] Exclude memory regions for the
2117 Ranges are in pairs (memory base and size).
2119 ports= [IP_VS_FTP] IPVS ftp helper module
2121 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2123 Format: <port>,<port>....
2125 print-fatal-signals=
2126 [KNL] debug: print fatal signals
2128 If enabled, warn about various signal handling
2129 related application anomalies: too many signals,
2130 too many POSIX.1 timers, fatal signals causing a
2133 If you hit the warning due to signal overflow,
2134 you might want to try "ulimit -i unlimited".
2138 printk.time= Show timing data prefixed to each printk message line
2139 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2141 processor.max_cstate= [HW,ACPI]
2142 Limit processor to maximum C-state
2143 max_cstate=9 overrides any DMI blacklist limit.
2145 processor.nocst [HW,ACPI]
2146 Ignore the _CST method to determine C-states,
2147 instead using the legacy FADT method
2149 profile= [KNL] Enable kernel profiling via /proc/profile
2150 Format: [schedule,]<number>
2151 Param: "schedule" - profile schedule points.
2152 Param: <number> - step/bucket size as a power of 2 for
2153 statistical time based profiling.
2154 Param: "sleep" - profile D-state sleeping (millisecs).
2155 Requires CONFIG_SCHEDSTATS
2156 Param: "kvm" - profile VM exits.
2158 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2160 See Documentation/blockdev/ramdisk.txt.
2162 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2163 probe for; one of (bare|imps|exps|lifebook|any).
2164 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2166 psmouse.resetafter= [HW,MOUSE]
2167 Try to reset the device after so many bad packets
2170 [HW,MOUSE] Set desired mouse resolution, in dpi.
2171 psmouse.smartscroll=
2172 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2173 0 = disabled, 1 = enabled (default).
2175 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
2177 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
2180 See Documentation/blockdev/paride.txt.
2183 [KNL] Number of legacy pty's. Overwrites compiled-in
2186 quiet [KNL] Disable most log messages
2191 See Documentation/md.txt.
2193 ramdisk_blocksize= [RAM]
2194 See Documentation/blockdev/ramdisk.txt.
2196 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2197 See Documentation/blockdev/ramdisk.txt.
2199 rcupdate.blimit= [KNL,BOOT]
2200 Set maximum number of finished RCU callbacks to process
2203 rcupdate.qhimark= [KNL,BOOT]
2204 Set threshold of queued
2205 RCU callbacks over which batch limiting is disabled.
2207 rcupdate.qlowmark= [KNL,BOOT]
2208 Set threshold of queued RCU callbacks below which
2209 batch limiting is re-enabled.
2213 Run specified binary instead of /init from the ramdisk,
2214 used for early userspace startup. See initrd.
2216 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2217 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2218 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2221 [KNL, SMP] Set scheduler's default relax_domain_level.
2222 See Documentation/cgroups/cpusets.txt.
2224 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2226 reservetop= [X86-32]
2228 Reserves a hole at the top of the kernel virtual
2231 reset_devices [KNL] Force drivers to reset the underlying device
2232 during initialization.
2235 Specify the partition device for software suspend
2237 resume_offset= [SWSUSP]
2238 Specify the offset from the beginning of the partition
2239 given by "resume=" at which the swap header is located,
2240 in <PAGE_SIZE> units (needed only for swap files).
2241 See Documentation/power/swsusp-and-swap-files.txt
2243 retain_initrd [RAM] Keep initrd memory after extraction
2245 rhash_entries= [KNL,NET]
2246 Set number of hash buckets for route cache
2248 riscom8= [HW,SERIAL]
2249 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2251 ro [KNL] Mount root device read-only on boot
2253 root= [KNL] Root filesystem
2255 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2256 mount the root filesystem
2258 rootflags= [KNL] Set root filesystem mount option string
2260 rootfstype= [KNL] Set root filesystem type
2262 rootwait [KNL] Wait (indefinitely) for root device to show up.
2263 Useful for devices that are detected asynchronously
2264 (e.g. USB and MMC devices).
2266 rw [KNL] Mount root device read-write on boot
2268 S [KNL] Run init in single mode
2271 See drivers/net/irda/sa1100_ir.c.
2273 sbni= [NET] Granch SBNI12 leased line adapter
2275 sched_debug [KNL] Enables verbose scheduler debug messages.
2277 scsi_debug_*= [SCSI]
2278 See drivers/scsi/scsi_debug.c.
2280 scsi_default_dev_flags=
2281 [SCSI] SCSI default device flags
2284 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2285 Format: <vendor>:<model>:<flags>
2286 (flags are integer value)
2288 scsi_logging_level= [SCSI] a bit mask of logging levels
2289 See drivers/scsi/scsi_logging.h for bits. Also
2290 settable via sysctl at dev.scsi.logging_level
2291 (/proc/sys/dev/scsi/logging_level).
2292 There is also a nice 'scsi_logging_level' script in the
2293 S390-tools package, available for download at
2294 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2296 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2297 discovered. async scans them in kernel threads,
2298 allowing boot to proceed. none ignores them, expecting
2299 user space to do the scan.
2301 security= [SECURITY] Choose a security module to enable at boot.
2302 If this boot parameter is not specified, only the first
2303 security module asking for security registration will be
2304 loaded. An invalid security module name will be treated
2305 as if no module has been chosen.
2307 selinux= [SELINUX] Disable or enable SELinux at boot time.
2308 Format: { "0" | "1" }
2309 See security/selinux/Kconfig help text.
2312 Default value is set via kernel config option.
2313 If enabled at boot time, /selinux/disable can be used
2314 later to disable prior to initial policy load.
2316 serialnumber [BUGS=X86-32]
2319 Maximal number of shapers.
2321 show_msr= [x86] show boot-time MSR settings
2322 Format: { <integer> }
2323 Show boot-time (BIOS-initialized) MSR settings.
2324 The parameter means the number of CPUs to show,
2325 for example 1 means boot CPU only.
2328 See header of drivers/scsi/sim710.c.
2335 slub_debug[=options[,slabs]] [MM, SLUB]
2336 Enabling slub_debug allows one to determine the
2337 culprit if slab objects become corrupted. Enabling
2338 slub_debug can create guard zones around objects and
2339 may poison objects when not in use. Also tracks the
2340 last alloc / free. For more information see
2341 Documentation/vm/slub.txt.
2343 slub_max_order= [MM, SLUB]
2344 Determines the maximum allowed order for slabs.
2345 A high setting may cause OOMs due to memory
2346 fragmentation. For more information see
2347 Documentation/vm/slub.txt.
2349 slub_min_objects= [MM, SLUB]
2350 The minimum number of objects per slab. SLUB will
2351 increase the slab order up to slub_max_order to
2352 generate a sufficiently large slab able to contain
2353 the number of objects indicated. The higher the number
2354 of objects the smaller the overhead of tracking slabs
2355 and the less frequently locks need to be acquired.
2356 For more information see Documentation/vm/slub.txt.
2358 slub_min_order= [MM, SLUB]
2359 Determines the mininum page order for slabs. Must be
2360 lower than slub_max_order.
2361 For more information see Documentation/vm/slub.txt.
2363 slub_nomerge [MM, SLUB]
2364 Disable merging of slabs with similar size. May be
2365 necessary if there is some reason to distinguish
2366 allocs to different slabs. Debug options disable
2367 merging on their own.
2368 For more information see Documentation/vm/slub.txt.
2371 Format: <io1>[,<io2>[,...,<io8>]]
2373 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2374 attempt to substitute SMP alternatives once at boot.
2376 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2377 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2378 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2379 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2380 smsc-ircc2.ircc_irq= [HW] IRQ line
2381 smsc-ircc2.ircc_dma= [HW] DMA channel
2382 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2383 0: Toshiba Satellite 1800 (GP data pin select)
2384 1: Fast pin select (default)
2387 snd-ad1816a= [HW,ALSA]
2389 snd-ad1848= [HW,ALSA]
2391 snd-ali5451= [HW,ALSA]
2393 snd-als100= [HW,ALSA]
2395 snd-als4000= [HW,ALSA]
2397 snd-azt2320= [HW,ALSA]
2399 snd-cmi8330= [HW,ALSA]
2401 snd-cmipci= [HW,ALSA]
2403 snd-cs4231= [HW,ALSA]
2405 snd-cs4232= [HW,ALSA]
2407 snd-cs4236= [HW,ALSA]
2409 snd-cs4281= [HW,ALSA]
2411 snd-cs46xx= [HW,ALSA]
2413 snd-dt019x= [HW,ALSA]
2415 snd-dummy= [HW,ALSA]
2417 snd-emu10k1= [HW,ALSA]
2419 snd-ens1370= [HW,ALSA]
2421 snd-ens1371= [HW,ALSA]
2423 snd-es968= [HW,ALSA]
2425 snd-es1688= [HW,ALSA]
2427 snd-es18xx= [HW,ALSA]
2429 snd-es1938= [HW,ALSA]
2431 snd-es1968= [HW,ALSA]
2433 snd-fm801= [HW,ALSA]
2435 snd-gusclassic= [HW,ALSA]
2437 snd-gusextreme= [HW,ALSA]
2439 snd-gusmax= [HW,ALSA]
2443 snd-ice1712= [HW,ALSA]
2445 snd-intel8x0= [HW,ALSA]
2447 snd-interwave= [HW,ALSA]
2452 snd-korg1212= [HW,ALSA]
2454 snd-maestro3= [HW,ALSA]
2456 snd-mpu401= [HW,ALSA]
2458 snd-mtpav= [HW,ALSA]
2460 snd-nm256= [HW,ALSA]
2462 snd-opl3sa2= [HW,ALSA]
2470 snd-opti93x= [HW,ALSA]
2474 snd-rme32= [HW,ALSA]
2476 snd-rme96= [HW,ALSA]
2478 snd-rme9652= [HW,ALSA]
2484 snd-sbawe= [HW,ALSA]
2486 snd-serial= [HW,ALSA]
2488 snd-sgalaxy= [HW,ALSA]
2490 snd-sonicvibes= [HW,ALSA]
2495 snd-sun-cs4231= [HW,ALSA]
2497 snd-trident= [HW,ALSA]
2499 snd-usb-audio= [HW,ALSA,USB]
2501 snd-via82xx= [HW,ALSA]
2503 snd-virmidi= [HW,ALSA]
2505 snd-wavefront= [HW,ALSA]
2507 snd-ymfpci= [HW,ALSA]
2510 [KNL] Should the soft-lockup detector generate panics.
2512 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2513 See Documentation/sonypi.txt
2515 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2516 See Documentation/serial/specialix.txt.
2518 spia_io_base= [HW,MTD]
2524 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2526 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2527 See Documentation/scsi/st.txt.
2530 Enabled the stack tracer on boot up.
2534 Set the STI (builtin display/keyboard on the HP-PARISC
2535 machines) console (graphic card) which should be used
2536 as the initial boot-console.
2537 See also comment in drivers/video/console/sticore.c.
2540 See comment in drivers/video/console/sticore.c.
2543 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2545 sunrpc.min_resvport=
2546 sunrpc.max_resvport=
2548 SunRPC servers often require that client requests
2549 originate from a privileged port (i.e. a port in the
2550 range 0 < portnr < 1024).
2551 An administrator who wishes to reserve some of these
2552 ports for other uses may adjust the range that the
2553 kernel's sunrpc client considers to be privileged
2554 using these two parameters to set the minimum and
2555 maximum port values.
2559 Control how the NFS server code allocates CPUs to
2560 service thread pools. Depending on how many NICs
2561 you have and where their interrupts are bound, this
2562 option will affect which CPUs will do NFS serving.
2563 Note: this parameter cannot be changed while the
2564 NFS server is running.
2566 auto the server chooses an appropriate mode
2567 automatically using heuristics
2568 global a single global pool contains all CPUs
2569 percpu one pool for each CPU
2570 pernode one pool for each NUMA node (equivalent
2571 to global on non-NUMA machines)
2573 sunrpc.tcp_slot_table_entries=
2574 sunrpc.udp_slot_table_entries=
2576 Sets the upper limit on the number of simultaneous
2577 RPC calls that can be sent from the client to a
2578 server. Increasing these values may allow you to
2579 improve throughput, but will also increase the
2580 amount of memory reserved for use by the client.
2582 swiotlb= [IA-64] Number of I/O TLB slabs
2586 sym53c416= [HW,SCSI]
2587 See header of drivers/scsi/sym53c416.c.
2589 sysrq_always_enabled
2591 Ignore sysrq setting - this boot parameter will
2592 neutralize any effect of /proc/sys/kernel/sysrq.
2593 Useful for debugging.
2596 See header of drivers/scsi/t128.c.
2600 test_suspend= [SUSPEND]
2601 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2602 standby suspend) as the system sleep state to briefly
2603 enter during system startup. The system is woken from
2604 this state using a wakeup-capable RTC alarm.
2606 thash_entries= [KNL,NET]
2607 Set number of hash buckets for TCP connection
2609 thermal.act= [HW,ACPI]
2610 -1: disable all active trip points in all thermal zones
2611 <degrees C>: override all lowest active trip points
2613 thermal.crt= [HW,ACPI]
2614 -1: disable all critical trip points in all thermal zones
2615 <degrees C>: override all critical trip points
2617 thermal.nocrt= [HW,ACPI]
2618 Set to disable actions on ACPI thermal zone
2619 critical and hot trip points.
2621 thermal.off= [HW,ACPI]
2622 1: disable ACPI thermal control
2624 thermal.psv= [HW,ACPI]
2625 -1: disable all passive trip points
2626 <degrees C>: override all passive trip points to this
2629 thermal.tzp= [HW,ACPI]
2630 Specify global default ACPI thermal zone polling rate
2631 <deci-seconds>: poll all this frequency
2632 0: no polling (default)
2635 See comment before function dc390_setup() in
2636 drivers/scsi/tmscsim.c.
2640 Specify if the kernel should make use of the cpu
2641 topology informations if the hardware supports these.
2642 The scheduler will make use of these informations and
2643 e.g. base its process migration decisions on it.
2648 tpm_suspend_pcr=[HW,TPM]
2649 Format: integer pcr id
2650 Specify that at suspend time, the tpm driver
2651 should extend the specified pcr with zeros,
2652 as a workaround for some chips which fail to
2653 flush the last written pcr on TPM_SaveState.
2654 This will guarantee that all the other pcrs
2657 trace_buf_size=nn[KMG]
2658 [FTRACE] will set tracing buffer size.
2660 trace_event=[event-list]
2661 [FTRACE] Set and start specified trace events in order
2662 to facilitate early boot debugging.
2663 See also Documentation/trace/events.txt
2665 trix= [HW,OSS] MediaTrix AudioTrix Pro
2667 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2669 tsc= Disable clocksource-must-verify flag for TSC.
2671 [x86] reliable: mark tsc clocksource as reliable, this
2672 disables clocksource verification at runtime.
2673 Used to enable high-resolution timer mode on older
2674 hardware, and in virtualized environment.
2675 [x86] noirqtime: Do not use TSC to do irq accounting.
2676 Used to run time disable IRQ_TIME_ACCOUNTING on any
2677 platforms where RDTSC is slow and this accounting
2680 turbografx.map[2|3]= [HW,JOY]
2681 TurboGraFX parallel port interface
2683 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2684 See also Documentation/input/joystick-parport.txt
2686 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2687 See header of drivers/scsi/u14-34f.c.
2695 uhash_entries= [KNL,NET]
2696 Set number of hash buckets for UDP/UDP-Lite connections
2699 [USB] Ignore overcurrent events (default N).
2700 Some badly-designed motherboards generate lots of
2701 bogus events, for ports that aren't wired to
2702 anything. Set this parameter to avoid log spamming.
2703 Note that genuine overcurrent events won't be
2708 Set unknown_nmi_panic=1 early on boot.
2710 usbcore.autosuspend=
2711 [USB] The autosuspend time delay (in seconds) used
2712 for newly-detected USB devices (default 2). This
2713 is the time required before an idle device will be
2714 autosuspended. Devices for which the delay is set
2715 to a negative value won't be autosuspended at all.
2717 usbcore.usbfs_snoop=
2718 [USB] Set to log all usbfs traffic (default 0 = off).
2720 usbcore.blinkenlights=
2721 [USB] Set to cycle leds on hubs (default 0 = off).
2723 usbcore.old_scheme_first=
2724 [USB] Start with the old device initialization
2725 scheme (default 0 = off).
2727 usbcore.use_both_schemes=
2728 [USB] Try the other device initialization scheme
2729 if the first one fails (default 1 = enabled).
2731 usbcore.initial_descriptor_timeout=
2732 [USB] Specifies timeout for the initial 64-byte
2733 USB_REQ_GET_DESCRIPTOR request in milliseconds
2734 (default 5000 = 5.0 seconds).
2737 [USBHID] The interval which mice are to be polled at.
2739 usb-storage.delay_use=
2740 [UMS] The delay in seconds before a new device is
2741 scanned for Logical Units (default 5).
2744 [UMS] A list of quirks entries to supplement or
2745 override the built-in unusual_devs list. List
2746 entries are separated by commas. Each entry has
2747 the form VID:PID:Flags where VID and PID are Vendor
2748 and Product ID values (4-digit hex numbers) and
2749 Flags is a set of characters, each corresponding
2750 to a common usb-storage quirk flag as follows:
2751 a = SANE_SENSE (collect more than 18 bytes
2753 b = BAD_SENSE (don't collect more than 18
2754 bytes of sense data);
2755 c = FIX_CAPACITY (decrease the reported
2756 device capacity by one sector);
2757 h = CAPACITY_HEURISTICS (decrease the
2758 reported device capacity by one
2759 sector if the number is odd);
2760 i = IGNORE_DEVICE (don't bind to this
2762 l = NOT_LOCKABLE (don't try to lock and
2763 unlock ejectable media);
2764 m = MAX_SECTORS_64 (don't transfer more
2765 than 64 sectors = 32 KB at a time);
2766 o = CAPACITY_OK (accept the capacity
2767 reported by the device);
2768 r = IGNORE_RESIDUE (the device reports
2769 bogus residue values);
2770 s = SINGLE_LUN (the device has only one
2772 w = NO_WP_DETECT (don't test whether the
2773 medium is write-protected).
2774 Example: quirks=0419:aaf5:rl,0421:0433:rc
2777 [X86] Flags controlling user PTE allocations.
2779 nohigh = do not allocate PTE pages in
2780 HIGHMEM regardless of setting
2784 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2785 vdso=1: enable VDSO (default)
2786 vdso=0: disable VDSO mapping
2789 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2790 vdso32=1: enable 32-bit VDSO (default)
2791 vdso32=0: disable 32-bit VDSO mapping
2794 vector=percpu: enable percpu vector domain
2796 video= [FB] Frame buffer configuration
2797 See Documentation/fb/modedb.txt.
2799 vga= [BOOT,X86-32] Select a particular video mode
2800 See Documentation/x86/boot.txt and
2801 Documentation/svga.txt.
2802 Use vga=ask for menu.
2803 This is actually a boot loader parameter; the value is
2804 passed to the kernel using a special protocol.
2806 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2807 size of <nn>. This can be used to increase the
2808 minimum size (128MB on x86). It can also be used to
2809 decrease the size and leave more room for directly
2812 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2815 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2818 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2821 vt.cur_default= [VT] Default cursor shape.
2822 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2823 the parameters of the <Esc>[?A;B;Cc escape sequence;
2824 see VGA-softcursor.txt. Default: 2 = underline.
2826 vt.default_blu= [VT]
2827 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2828 Change the default blue palette of the console.
2829 This is a 16-member array composed of values
2832 vt.default_grn= [VT]
2833 Format: <green0>,<green1>,<green2>,...,<green15>
2834 Change the default green palette of the console.
2835 This is a 16-member array composed of values
2838 vt.default_red= [VT]
2839 Format: <red0>,<red1>,<red2>,...,<red15>
2840 Change the default red palette of the console.
2841 This is a 16-member array composed of values
2847 Set system-wide default UTF-8 mode for all tty's.
2848 Default is 1, i.e. UTF-8 mode is enabled for all
2849 newly opened terminals.
2851 vt.global_cursor_default=
2854 Set system-wide default for whether a cursor
2855 is shown on new VTs. Default is -1,
2856 i.e. cursors will be created by default unless
2857 overridden by individual drivers. 0 will hide
2858 cursors, 1 will display them.
2860 waveartist= [HW,OSS]
2861 Format: <io>,<irq>,<dma>,<dma2>
2864 See header of drivers/scsi/wd33c93.c.
2867 See header of drivers/scsi/wd7000.c.
2869 watchdog timers [HW,WDT] For information on watchdog timers,
2870 see Documentation/watchdog/watchdog-parameters.txt
2871 or other driver-specific files in the
2872 Documentation/watchdog/ directory.
2874 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2875 default x2apic cluster mode on platforms
2878 x86_mrst_timer= [X86-32,APBT]
2879 Choose timer option for x86 Moorestown MID platform.
2880 Two valid options are apbt timer only and lapic timer
2881 plus one apbt timer for broadcast timer.
2882 x86_mrst_timer=apbt_only | lapic_and_apbt
2884 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2885 xd_geo= See header of drivers/block/xd.c.
2887 xirc2ps_cs= [NET,PCMCIA]
2889 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2891 ______________________________________________________________________
2895 Add documentation for ALSA options.
2896 Add more DRM drivers.