kernel-parameters.txt 81 KB

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  1. Kernel Parameters
  2. ~~~~~~~~~~~~~~~~~
  3. The following is a consolidated list of the kernel parameters as implemented
  4. (mostly) by the __setup() macro and sorted into English Dictionary order
  5. (defined as ignoring all punctuation and sorting digits before letters in a
  6. case insensitive manner), and with descriptions where known.
  7. Module parameters for loadable modules are specified only as the
  8. parameter name with optional '=' and value as appropriate, such as:
  9. modprobe usbcore blinkenlights=1
  10. Module parameters for modules that are built into the kernel image
  11. are specified on the kernel command line with the module name plus
  12. '.' plus parameter name, with '=' and value if appropriate, such as:
  13. usbcore.blinkenlights=1
  14. This document may not be entirely up to date and comprehensive. The command
  15. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  16. module. Loadable modules, after being loaded into the running kernel, also
  17. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  18. parameters may be changed at runtime by the command
  19. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  20. The parameters listed below are only valid if certain kernel build options were
  21. enabled and if respective hardware is present. The text in square brackets at
  22. the beginning of each description states the restrictions within which a
  23. parameter is applicable:
  24. ACPI ACPI support is enabled.
  25. AGP AGP (Accelerated Graphics Port) is enabled.
  26. ALSA ALSA sound support is enabled.
  27. APIC APIC support is enabled.
  28. APM Advanced Power Management support is enabled.
  29. AVR32 AVR32 architecture is enabled.
  30. AX25 Appropriate AX.25 support is enabled.
  31. BLACKFIN Blackfin architecture is enabled.
  32. DRM Direct Rendering Management support is enabled.
  33. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  34. EFI EFI Partitioning (GPT) is enabled
  35. EIDE EIDE/ATAPI support is enabled.
  36. FB The frame buffer device is enabled.
  37. HW Appropriate hardware is enabled.
  38. IA-64 IA-64 architecture is enabled.
  39. IMA Integrity measurement architecture is enabled.
  40. IOSCHED More than one I/O scheduler is enabled.
  41. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  42. ISAPNP ISA PnP code is enabled.
  43. ISDN Appropriate ISDN support is enabled.
  44. JOY Appropriate joystick support is enabled.
  45. KMEMTRACE kmemtrace is enabled.
  46. LIBATA Libata driver is enabled
  47. LP Printer support is enabled.
  48. LOOP Loopback device support is enabled.
  49. M68k M68k architecture is enabled.
  50. These options have more detailed description inside of
  51. Documentation/m68k/kernel-options.txt.
  52. MCA MCA bus support is enabled.
  53. MDA MDA console support is enabled.
  54. MOUSE Appropriate mouse support is enabled.
  55. MSI Message Signaled Interrupts (PCI).
  56. MTD MTD (Memory Technology Device) support is enabled.
  57. NET Appropriate network support is enabled.
  58. NUMA NUMA support is enabled.
  59. GENERIC_TIME The generic timeofday code is enabled.
  60. NFS Appropriate NFS support is enabled.
  61. OSS OSS sound support is enabled.
  62. PV_OPS A paravirtualized kernel is enabled.
  63. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  64. PARISC The PA-RISC architecture is enabled.
  65. PCI PCI bus support is enabled.
  66. PCIE PCI Express support is enabled.
  67. PCMCIA The PCMCIA subsystem is enabled.
  68. PNP Plug & Play support is enabled.
  69. PPC PowerPC architecture is enabled.
  70. PPT Parallel port support is enabled.
  71. PS2 Appropriate PS/2 support is enabled.
  72. RAM RAM disk support is enabled.
  73. ROOTPLUG The example Root Plug LSM is enabled.
  74. S390 S390 architecture is enabled.
  75. SCSI Appropriate SCSI support is enabled.
  76. A lot of drivers has their options described inside of
  77. Documentation/scsi/.
  78. SECURITY Different security models are enabled.
  79. SELINUX SELinux support is enabled.
  80. SERIAL Serial support is enabled.
  81. SH SuperH architecture is enabled.
  82. SMP The kernel is an SMP kernel.
  83. SPARC Sparc architecture is enabled.
  84. SWSUSP Software suspend (hibernation) is enabled.
  85. SUSPEND System suspend states are enabled.
  86. FTRACE Function tracing enabled.
  87. TS Appropriate touchscreen support is enabled.
  88. UMS USB Mass Storage support is enabled.
  89. USB USB support is enabled.
  90. USBHID USB Human Interface Device support is enabled.
  91. V4L Video For Linux support is enabled.
  92. VGA The VGA console has been enabled.
  93. VT Virtual terminal support is enabled.
  94. WDT Watchdog support is enabled.
  95. XT IBM PC/XT MFM hard disk support is enabled.
  96. X86-32 X86-32, aka i386 architecture is enabled.
  97. X86-64 X86-64 architecture is enabled.
  98. More X86-64 boot options can be found in
  99. Documentation/x86/x86_64/boot-options.txt .
  100. X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
  101. In addition, the following text indicates that the option:
  102. BUGS= Relates to possible processor bugs on the said processor.
  103. KNL Is a kernel start-up parameter.
  104. BOOT Is a boot loader parameter.
  105. Parameters denoted with BOOT are actually interpreted by the boot
  106. loader, and have no meaning to the kernel directly.
  107. Do not modify the syntax of boot loader parameters without extreme
  108. need or coordination with <Documentation/x86/boot.txt>.
  109. There are also arch-specific kernel-parameters not documented here.
  110. See for example <Documentation/x86/x86_64/boot-options.txt>.
  111. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  112. a trailing = on the name of any parameter states that that parameter will
  113. be entered as an environment variable, whereas its absence indicates that
  114. it will appear as a kernel argument readable via /proc/cmdline by programs
  115. running once the system is up.
  116. The number of kernel parameters is not limited, but the length of the
  117. complete command line (parameters including spaces etc.) is limited to
  118. a fixed number of characters. This limit depends on the architecture
  119. and is between 256 and 4096 characters. It is defined in the file
  120. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  121. acpi= [HW,ACPI,X86-64,i386]
  122. Advanced Configuration and Power Interface
  123. Format: { force | off | ht | strict | noirq | rsdt }
  124. force -- enable ACPI if default was off
  125. off -- disable ACPI if default was on
  126. noirq -- do not use ACPI for IRQ routing
  127. ht -- run only enough ACPI to enable Hyper Threading
  128. strict -- Be less tolerant of platforms that are not
  129. strictly ACPI specification compliant.
  130. rsdt -- prefer RSDT over (default) XSDT
  131. See also Documentation/power/pm.txt, pci=noacpi
  132. acpi_apic_instance= [ACPI, IOAPIC]
  133. Format: <int>
  134. 2: use 2nd APIC table, if available
  135. 1,0: use 1st APIC table
  136. default: 0
  137. acpi_backlight= [HW,ACPI]
  138. acpi_backlight=vendor
  139. acpi_backlight=video
  140. If set to vendor, prefer vendor specific driver
  141. (e.g. thinkpad_acpi, sony_acpi, etc.) instead
  142. of the ACPI video.ko driver.
  143. acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
  144. acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
  145. Format: <int>
  146. CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
  147. debug output. Bits in debug_layer correspond to a
  148. _COMPONENT in an ACPI source file, e.g.,
  149. #define _COMPONENT ACPI_PCI_COMPONENT
  150. Bits in debug_level correspond to a level in
  151. ACPI_DEBUG_PRINT statements, e.g.,
  152. ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
  153. The debug_level mask defaults to "info". See
  154. Documentation/acpi/debug.txt for more information about
  155. debug layers and levels.
  156. Enable processor driver info messages:
  157. acpi.debug_layer=0x20000000
  158. Enable PCI/PCI interrupt routing info messages:
  159. acpi.debug_layer=0x400000
  160. Enable AML "Debug" output, i.e., stores to the Debug
  161. object while interpreting AML:
  162. acpi.debug_layer=0xffffffff acpi.debug_level=0x2
  163. Enable all messages related to ACPI hardware:
  164. acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
  165. Some values produce so much output that the system is
  166. unusable. The "log_buf_len" parameter may be useful
  167. if you need to capture more output.
  168. acpi_display_output= [HW,ACPI]
  169. acpi_display_output=vendor
  170. acpi_display_output=video
  171. See above.
  172. acpi_irq_balance [HW,ACPI]
  173. ACPI will balance active IRQs
  174. default in APIC mode
  175. acpi_irq_nobalance [HW,ACPI]
  176. ACPI will not move active IRQs (default)
  177. default in PIC mode
  178. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  179. Format: <irq>,<irq>...
  180. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  181. use by PCI
  182. Format: <irq>,<irq>...
  183. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  184. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  185. Format: To spoof as Windows 98: ="Microsoft Windows"
  186. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  187. acpi_osi="string1" # add string1 -- only one string
  188. acpi_osi="!string2" # remove built-in string2
  189. acpi_osi= # disable all strings
  190. acpi_pm_good [X86-32,X86-64]
  191. Override the pmtimer bug detection: force the kernel
  192. to assume that this machine's pmtimer latches its value
  193. and always returns good values.
  194. acpi.power_nocheck= [HW,ACPI]
  195. Format: 1/0 enable/disable the check of power state.
  196. On some bogus BIOS the _PSC object/_STA object of
  197. power resource can't return the correct device power
  198. state. In such case it is unneccessary to check its
  199. power state again in power transition.
  200. 1 : disable the power state check
  201. acpi_enforce_resources= [ACPI]
  202. { strict | lax | no }
  203. Check for resource conflicts between native drivers
  204. and ACPI OperationRegions (SystemIO and SystemMemory
  205. only). IO ports and memory declared in ACPI might be
  206. used by the ACPI subsystem in arbitrary AML code and
  207. can interfere with legacy drivers.
  208. strict (default): access to resources claimed by ACPI
  209. is denied; legacy drivers trying to access reserved
  210. resources will fail to bind to device using them.
  211. lax: access to resources claimed by ACPI is allowed;
  212. legacy drivers trying to access reserved resources
  213. will bind successfully but a warning message is logged.
  214. no: ACPI OperationRegions are not marked as reserved,
  215. no further checks are performed.
  216. ad1848= [HW,OSS]
  217. Format: <io>,<irq>,<dma>,<dma2>,<type>
  218. advansys= [HW,SCSI]
  219. See header of drivers/scsi/advansys.c.
  220. advwdt= [HW,WDT] Advantech WDT
  221. Format: <iostart>,<iostop>
  222. aedsp16= [HW,OSS] Audio Excel DSP 16
  223. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  224. See also header of sound/oss/aedsp16.c.
  225. agp= [AGP]
  226. { off | try_unsupported }
  227. off: disable AGP support
  228. try_unsupported: try to drive unsupported chipsets
  229. (may crash computer or cause data corruption)
  230. aha152x= [HW,SCSI]
  231. See Documentation/scsi/aha152x.txt.
  232. aha1542= [HW,SCSI]
  233. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  234. aic7xxx= [HW,SCSI]
  235. See Documentation/scsi/aic7xxx.txt.
  236. aic79xx= [HW,SCSI]
  237. See Documentation/scsi/aic79xx.txt.
  238. amd_iommu= [HW,X86-84]
  239. Pass parameters to the AMD IOMMU driver in the system.
  240. Possible values are:
  241. isolate - enable device isolation (each device, as far
  242. as possible, will get its own protection
  243. domain) [default]
  244. share - put every device behind one IOMMU into the
  245. same protection domain
  246. fullflush - enable flushing of IO/TLB entries when
  247. they are unmapped. Otherwise they are
  248. flushed before they will be reused, which
  249. is a lot of faster
  250. amd_iommu_size= [HW,X86-64]
  251. Define the size of the aperture for the AMD IOMMU
  252. driver. Possible values are:
  253. '32M', '64M' (default), '128M', '256M', '512M', '1G'
  254. amijoy.map= [HW,JOY] Amiga joystick support
  255. Map of devices attached to JOY0DAT and JOY1DAT
  256. Format: <a>,<b>
  257. See also Documentation/kernel/input/joystick.txt
  258. analog.map= [HW,JOY] Analog joystick and gamepad support
  259. Specifies type or capabilities of an analog joystick
  260. connected to one of 16 gameports
  261. Format: <type1>,<type2>,..<type16>
  262. apc= [HW,SPARC]
  263. Power management functions (SPARCstation-4/5 + deriv.)
  264. Format: noidle
  265. Disable APC CPU standby support. SPARCstation-Fox does
  266. not play well with APC CPU idle - disable it if you have
  267. APC and your system crashes randomly.
  268. apic= [APIC,i386] Advanced Programmable Interrupt Controller
  269. Change the output verbosity whilst booting
  270. Format: { quiet (default) | verbose | debug }
  271. Change the amount of debugging information output
  272. when initialising the APIC and IO-APIC components.
  273. apm= [APM] Advanced Power Management
  274. See header of arch/x86/kernel/apm_32.c.
  275. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  276. Format: <io>,<irq>,<nodeID>
  277. ataflop= [HW,M68k]
  278. atarimouse= [HW,MOUSE] Atari Mouse
  279. atascsi= [HW,SCSI] Atari SCSI
  280. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  281. EzKey and similar keyboards
  282. atkbd.reset= [HW] Reset keyboard during initialization
  283. atkbd.set= [HW] Select keyboard code set
  284. Format: <int> (2 = AT (default), 3 = PS/2)
  285. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  286. keyboards
  287. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  288. Format: <bool> (0 = real, 1 = synthetic (default))
  289. atkbd.softrepeat= [HW]
  290. Use software keyboard repeat
  291. autotest [IA64]
  292. baycom_epp= [HW,AX25]
  293. Format: <io>,<mode>
  294. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  295. Format: <io>,<mode>
  296. See header of drivers/net/hamradio/baycom_par.c.
  297. baycom_ser_fdx= [HW,AX25]
  298. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  299. Format: <io>,<irq>,<mode>[,<baud>]
  300. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  301. baycom_ser_hdx= [HW,AX25]
  302. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  303. Format: <io>,<irq>,<mode>
  304. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  305. boot_delay= Milliseconds to delay each printk during boot.
  306. Values larger than 10 seconds (10000) are changed to
  307. no delay (0).
  308. Format: integer
  309. bootmem_debug [KNL] Enable bootmem allocator debug messages.
  310. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  311. bttv.radio= Most important insmod options are available as
  312. kernel args too.
  313. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  314. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  315. BusLogic= [HW,SCSI]
  316. See drivers/scsi/BusLogic.c, comment before function
  317. BusLogic_ParseDriverOptions().
  318. c101= [NET] Moxa C101 synchronous serial card
  319. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  320. Sometimes CPU hardware bugs make them report the cache
  321. size incorrectly. The kernel will attempt work arounds
  322. to fix known problems, but for some CPUs it is not
  323. possible to determine what the correct size should be.
  324. This option provides an override for these situations.
  325. capability.disable=
  326. [SECURITY] Disable capabilities. This would normally
  327. be used only if an alternative security model is to be
  328. configured. Potentially dangerous and should only be
  329. used if you are entirely sure of the consequences.
  330. ccw_timeout_log [S390]
  331. See Documentation/s390/CommonIO for details.
  332. cgroup_disable= [KNL] Disable a particular controller
  333. Format: {name of the controller(s) to disable}
  334. {Currently supported controllers - "memory"}
  335. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  336. Format: { "0" | "1" }
  337. See security/selinux/Kconfig help text.
  338. 0 -- check protection applied by kernel (includes
  339. any implied execute protection).
  340. 1 -- check protection requested by application.
  341. Default value is set via a kernel config option.
  342. Value can be changed at runtime via
  343. /selinux/checkreqprot.
  344. cio_ignore= [S390]
  345. See Documentation/s390/CommonIO for details.
  346. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  347. [Deprecated]
  348. Forces specified clocksource (if available) to be used
  349. when calculating gettimeofday(). If specified
  350. clocksource is not available, it defaults to PIT.
  351. Format: { pit | tsc | cyclone | pmtmr }
  352. clocksource= [GENERIC_TIME] Override the default clocksource
  353. Format: <string>
  354. Override the default clocksource and use the clocksource
  355. with the name specified.
  356. Some clocksource names to choose from, depending on
  357. the platform:
  358. [all] jiffies (this is the base, fallback clocksource)
  359. [ACPI] acpi_pm
  360. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  361. pxa_timer,timer3,32k_counter,timer0_1
  362. [AVR32] avr32
  363. [X86-32] pit,hpet,tsc,vmi-timer;
  364. scx200_hrt on Geode; cyclone on IBM x440
  365. [MIPS] MIPS
  366. [PARISC] cr16
  367. [S390] tod
  368. [SH] SuperH
  369. [SPARC64] tick
  370. [X86-64] hpet,tsc
  371. clearcpuid=BITNUM [X86]
  372. Disable CPUID feature X for the kernel. See
  373. arch/x86/include/asm/cpufeature.h for the valid bit
  374. numbers. Note the Linux specific bits are not necessarily
  375. stable over kernel options, but the vendor specific
  376. ones should be.
  377. Also note that user programs calling CPUID directly
  378. or using the feature without checking anything
  379. will still see it. This just prevents it from
  380. being used by the kernel or shown in /proc/cpuinfo.
  381. Also note the kernel might malfunction if you disable
  382. some critical bits.
  383. code_bytes [IA32/X86_64] How many bytes of object code to print
  384. in an oops report.
  385. Range: 0 - 8192
  386. Default: 64
  387. com20020= [HW,NET] ARCnet - COM20020 chipset
  388. Format:
  389. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  390. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  391. Format: <io>[,<irq>]
  392. com90xx= [HW,NET]
  393. ARCnet - COM90xx chipset (memory-mapped buffers)
  394. Format: <io>[,<irq>[,<memstart>]]
  395. condev= [HW,S390] console device
  396. conmode=
  397. console= [KNL] Output console device and options.
  398. tty<n> Use the virtual console device <n>.
  399. ttyS<n>[,options]
  400. ttyUSB0[,options]
  401. Use the specified serial port. The options are of
  402. the form "bbbbpnf", where "bbbb" is the baud rate,
  403. "p" is parity ("n", "o", or "e"), "n" is number of
  404. bits, and "f" is flow control ("r" for RTS or
  405. omit it). Default is "9600n8".
  406. See Documentation/serial-console.txt for more
  407. information. See
  408. Documentation/networking/netconsole.txt for an
  409. alternative.
  410. uart[8250],io,<addr>[,options]
  411. uart[8250],mmio,<addr>[,options]
  412. Start an early, polled-mode console on the 8250/16550
  413. UART at the specified I/O port or MMIO address,
  414. switching to the matching ttyS device later. The
  415. options are the same as for ttyS, above.
  416. If the device connected to the port is not a TTY but a braille
  417. device, prepend "brl," before the device type, for instance
  418. console=brl,ttyS0
  419. For now, only VisioBraille is supported.
  420. coredump_filter=
  421. [KNL] Change the default value for
  422. /proc/<pid>/coredump_filter.
  423. See also Documentation/filesystems/proc.txt.
  424. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  425. Format:
  426. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  427. crashkernel=nn[KMG]@ss[KMG]
  428. [KNL] Reserve a chunk of physical memory to
  429. hold a kernel to switch to with kexec on panic.
  430. crashkernel=range1:size1[,range2:size2,...][@offset]
  431. [KNL] Same as above, but depends on the memory
  432. in the running system. The syntax of range is
  433. start-[end] where start and end are both
  434. a memory unit (amount[KMG]). See also
  435. Documentation/kdump/kdump.txt for a example.
  436. cs89x0_dma= [HW,NET]
  437. Format: <dma>
  438. cs89x0_media= [HW,NET]
  439. Format: { rj45 | aui | bnc }
  440. dasd= [HW,NET]
  441. See header of drivers/s390/block/dasd_devmap.c.
  442. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  443. (one device per port)
  444. Format: <port#>,<type>
  445. See also Documentation/input/joystick-parport.txt
  446. debug [KNL] Enable kernel debugging (events log level).
  447. debug_locks_verbose=
  448. [KNL] verbose self-tests
  449. Format=<0|1>
  450. Print debugging info while doing the locking API
  451. self-tests.
  452. We default to 0 (no extra messages), setting it to
  453. 1 will print _a lot_ more information - normally
  454. only useful to kernel developers.
  455. debug_objects [KNL] Enable object debugging
  456. no_debug_objects
  457. [KNL] Disable object debugging
  458. debugpat [X86] Enable PAT debugging
  459. decnet.addr= [HW,NET]
  460. Format: <area>[,<node>]
  461. See also Documentation/networking/decnet.txt.
  462. default_hugepagesz=
  463. [same as hugepagesz=] The size of the default
  464. HugeTLB page size. This is the size represented by
  465. the legacy /proc/ hugepages APIs, used for SHM, and
  466. default size when mounting hugetlbfs filesystems.
  467. Defaults to the default architecture's huge page size
  468. if not specified.
  469. dhash_entries= [KNL]
  470. Set number of hash buckets for dentry cache.
  471. digi= [HW,SERIAL]
  472. IO parameters + enable/disable command.
  473. digiepca= [HW,SERIAL]
  474. See drivers/char/README.epca and
  475. Documentation/serial/digiepca.txt.
  476. disable_mtrr_cleanup [X86]
  477. The kernel tries to adjust MTRR layout from continuous
  478. to discrete, to make X server driver able to add WB
  479. entry later. This parameter disables that.
  480. disable_mtrr_trim [X86, Intel and AMD only]
  481. By default the kernel will trim any uncacheable
  482. memory out of your available memory pool based on
  483. MTRR settings. This parameter disables that behavior,
  484. possibly causing your machine to run very slowly.
  485. disable_timer_pin_1 [i386,x86-64]
  486. Disable PIN 1 of APIC timer
  487. Can be useful to work around chipset bugs.
  488. dmasound= [HW,OSS] Sound subsystem buffers
  489. dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
  490. this option disables the debugging code at boot.
  491. dma_debug_entries=<number>
  492. This option allows to tune the number of preallocated
  493. entries for DMA-API debugging code. One entry is
  494. required per DMA-API allocation. Use this if the
  495. DMA-API debugging code disables itself because the
  496. architectural default is too low.
  497. dscc4.setup= [NET]
  498. dtc3181e= [HW,SCSI]
  499. dynamic_printk Enables pr_debug()/dev_dbg() calls if
  500. CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
  501. These can also be switched on/off via
  502. <debugfs>/dynamic_printk/modules
  503. earlycon= [KNL] Output early console device and options.
  504. uart[8250],io,<addr>[,options]
  505. uart[8250],mmio,<addr>[,options]
  506. Start an early, polled-mode console on the 8250/16550
  507. UART at the specified I/O port or MMIO address.
  508. The options are the same as for ttyS, above.
  509. earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
  510. earlyprintk=vga
  511. earlyprintk=serial[,ttySn[,baudrate]]
  512. earlyprintk=dbgp
  513. Append ",keep" to not disable it when the real console
  514. takes over.
  515. Only vga or serial or usb debug port at a time.
  516. Currently only ttyS0 and ttyS1 are supported.
  517. Interaction with the standard serial driver is not
  518. very good.
  519. The VGA output is eventually overwritten by the real
  520. console.
  521. eata= [HW,SCSI]
  522. edd= [EDD]
  523. Format: {"off" | "on" | "skip[mbr]"}
  524. eisa_irq_edge= [PARISC,HW]
  525. See header of drivers/parisc/eisa.c.
  526. elanfreq= [X86-32]
  527. See comment before function elanfreq_setup() in
  528. arch/x86/kernel/cpu/cpufreq/elanfreq.c.
  529. elevator= [IOSCHED]
  530. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  531. See Documentation/block/as-iosched.txt and
  532. Documentation/block/deadline-iosched.txt for details.
  533. elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
  534. Specifies physical address of start of kernel core
  535. image elf header. Generally kexec loader will
  536. pass this option to capture kernel.
  537. See Documentation/kdump/kdump.txt for details.
  538. enable_mtrr_cleanup [X86]
  539. The kernel tries to adjust MTRR layout from continuous
  540. to discrete, to make X server driver able to add WB
  541. entry later. This parameter enables that.
  542. enable_timer_pin_1 [i386,x86-64]
  543. Enable PIN 1 of APIC timer
  544. Can be useful to work around chipset bugs
  545. (in particular on some ATI chipsets).
  546. The kernel tries to set a reasonable default.
  547. enforcing [SELINUX] Set initial enforcing status.
  548. Format: {"0" | "1"}
  549. See security/selinux/Kconfig help text.
  550. 0 -- permissive (log only, no denials).
  551. 1 -- enforcing (deny and log).
  552. Default value is 0.
  553. Value can be changed at runtime via /selinux/enforce.
  554. ether= [HW,NET] Ethernet cards parameters
  555. This option is obsoleted by the "netdev=" option, which
  556. has equivalent usage. See its documentation for details.
  557. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  558. Format: <io>[,<irq>]
  559. failslab=
  560. fail_page_alloc=
  561. fail_make_request=[KNL]
  562. General fault injection mechanism.
  563. Format: <interval>,<probability>,<space>,<times>
  564. See also /Documentation/fault-injection/.
  565. fd_mcs= [HW,SCSI]
  566. See header of drivers/scsi/fd_mcs.c.
  567. fdomain= [HW,SCSI]
  568. See header of drivers/scsi/fdomain.c.
  569. floppy= [HW]
  570. See Documentation/blockdev/floppy.txt.
  571. force_pal_cache_flush
  572. [IA-64] Avoid check_sal_cache_flush which may hang on
  573. buggy SAL_CACHE_FLUSH implementations. Using this
  574. parameter will force ia64_sal_cache_flush to call
  575. ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
  576. ftrace=[tracer]
  577. [ftrace] will set and start the specified tracer
  578. as early as possible in order to facilitate early
  579. boot debugging.
  580. ftrace_dump_on_oops
  581. [ftrace] will dump the trace buffers on oops.
  582. gamecon.map[2|3]=
  583. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  584. support via parallel port (up to 5 devices per port)
  585. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  586. See also Documentation/input/joystick-parport.txt
  587. gamma= [HW,DRM]
  588. gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
  589. Format: off | on
  590. default: on
  591. gdth= [HW,SCSI]
  592. See header of drivers/scsi/gdth.c.
  593. gpt [EFI] Forces disk with valid GPT signature but
  594. invalid Protective MBR to be treated as GPT.
  595. gvp11= [HW,SCSI]
  596. hashdist= [KNL,NUMA] Large hashes allocated during boot
  597. are distributed across NUMA nodes. Defaults on
  598. for IA-64, off otherwise.
  599. Format: 0 | 1 (for off | on)
  600. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  601. hd= [EIDE] (E)IDE hard drive subsystem geometry
  602. Format: <cyl>,<head>,<sect>
  603. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  604. size of <nn>. This works even on boxes that have no
  605. highmem otherwise. This also works to reduce highmem
  606. size on bigger boxes.
  607. highres= [KNL] Enable/disable high resolution timer mode.
  608. Valid parameters: "on", "off"
  609. Default: "on"
  610. hisax= [HW,ISDN]
  611. See Documentation/isdn/README.HiSax.
  612. hlt [BUGS=ARM,SH]
  613. hpet= [X86-32,HPET] option to control HPET usage
  614. Format: { enable (default) | disable | force |
  615. verbose }
  616. disable: disable HPET and use PIT instead
  617. force: allow force enabled of undocumented chips (ICH4,
  618. VIA, nVidia)
  619. verbose: show contents of HPET registers during setup
  620. hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
  621. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
  622. On x86-64 and powerpc, this option can be specified
  623. multiple times interleaved with hugepages= to reserve
  624. huge pages of different sizes. Valid pages sizes on
  625. x86-64 are 2M (when the CPU supports "pse") and 1G
  626. (when the CPU supports the "pdpe1gb" cpuinfo flag)
  627. Note that 1GB pages can only be allocated at boot time
  628. using hugepages= and not freed afterwards.
  629. hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
  630. terminal devices. Valid values: 0..8
  631. hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
  632. If specified, z/VM IUCV HVC accepts connections
  633. from listed z/VM user IDs only.
  634. i2c_bus= [HW] Override the default board specific I2C bus speed
  635. or register an additional I2C bus that is not
  636. registered from board initialization code.
  637. Format:
  638. <bus_id>,<clkrate>
  639. i8042.debug [HW] Toggle i8042 debug mode
  640. i8042.direct [HW] Put keyboard port into non-translated mode
  641. i8042.dumbkbd [HW] Pretend that controller can only read data from
  642. keyboard and cannot control its state
  643. (Don't attempt to blink the leds)
  644. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  645. i8042.nokbd [HW] Don't check/create keyboard port
  646. i8042.noloop [HW] Disable the AUX Loopback command while probing
  647. for the AUX port
  648. i8042.nomux [HW] Don't check presence of an active multiplexing
  649. controller
  650. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  651. controllers
  652. i8042.panicblink=
  653. [HW] Frequency with which keyboard LEDs should blink
  654. when kernel panics (default is 0.5 sec)
  655. i8042.reset [HW] Reset the controller during init and cleanup
  656. i8042.unlock [HW] Unlock (ignore) the keylock
  657. i810= [HW,DRM]
  658. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  659. indicates that the driver is running on unsupported
  660. hardware.
  661. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  662. does not match list of supported models.
  663. i8k.power_status
  664. [HW] Report power status in /proc/i8k
  665. (disabled by default)
  666. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  667. capability is set.
  668. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  669. See Documentation/mca.txt.
  670. icn= [HW,ISDN]
  671. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  672. ide-core.nodma= [HW] (E)IDE subsystem
  673. Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
  674. .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
  675. .chs .ignore_cable are additional options
  676. See Documentation/ide/ide.txt.
  677. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  678. See Documentation/ide/ide.txt.
  679. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
  680. Claim all unknown PCI IDE storage controllers.
  681. idle= [X86]
  682. Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
  683. Poll forces a polling idle loop that can slightly
  684. improve the performance of waking up a idle CPU, but
  685. will use a lot of power and make the system run hot.
  686. Not recommended.
  687. idle=mwait: On systems which support MONITOR/MWAIT but
  688. the kernel chose to not use it because it doesn't save
  689. as much power as a normal idle loop, use the
  690. MONITOR/MWAIT idle loop anyways. Performance should be
  691. the same as idle=poll.
  692. idle=halt: Halt is forced to be used for CPU idle.
  693. In such case C2/C3 won't be used again.
  694. idle=nomwait: Disable mwait for CPU C-states
  695. ignore_loglevel [KNL]
  696. Ignore loglevel setting - this will print /all/
  697. kernel messages to the console. Useful for debugging.
  698. ihash_entries= [KNL]
  699. Set number of hash buckets for inode cache.
  700. ima_audit= [IMA]
  701. Format: { "0" | "1" }
  702. 0 -- integrity auditing messages. (Default)
  703. 1 -- enable informational integrity auditing messages.
  704. ima_hash= [IMA]
  705. Formt: { "sha1" | "md5" }
  706. default: "sha1"
  707. in2000= [HW,SCSI]
  708. See header of drivers/scsi/in2000.c.
  709. init= [KNL]
  710. Format: <full_path>
  711. Run specified binary instead of /sbin/init as init
  712. process.
  713. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  714. for working out where the kernel is dying during
  715. startup.
  716. initrd= [BOOT] Specify the location of the initial ramdisk
  717. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  718. Format: <irq>
  719. intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
  720. on
  721. Enable intel iommu driver.
  722. off
  723. Disable intel iommu driver.
  724. igfx_off [Default Off]
  725. By default, gfx is mapped as normal device. If a gfx
  726. device has a dedicated DMAR unit, the DMAR unit is
  727. bypassed by not enabling DMAR with this option. In
  728. this case, gfx device will use physical address for
  729. DMA.
  730. forcedac [x86_64]
  731. With this option iommu will not optimize to look
  732. for io virtual address below 32 bit forcing dual
  733. address cycle on pci bus for cards supporting greater
  734. than 32 bit addressing. The default is to look
  735. for translation below 32 bit and if not available
  736. then look in the higher range.
  737. strict [Default Off]
  738. With this option on every unmap_single operation will
  739. result in a hardware IOTLB flush operation as opposed
  740. to batching them for performance.
  741. inttest= [IA64]
  742. iomem= Disable strict checking of access to MMIO memory
  743. strict regions from userspace.
  744. relaxed
  745. iommu= [x86]
  746. off
  747. force
  748. noforce
  749. biomerge
  750. panic
  751. nopanic
  752. merge
  753. nomerge
  754. forcesac
  755. soft
  756. io7= [HW] IO7 for Marvel based alpha systems
  757. See comment before marvel_specify_io7 in
  758. arch/alpha/kernel/core_marvel.c.
  759. io_delay= [X86-32,X86-64] I/O delay method
  760. 0x80
  761. Standard port 0x80 based delay
  762. 0xed
  763. Alternate port 0xed based delay (needed on some systems)
  764. udelay
  765. Simple two microseconds delay
  766. none
  767. No delay
  768. ip= [IP_PNP]
  769. See Documentation/filesystems/nfsroot.txt.
  770. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  771. See comment before ip2_setup() in
  772. drivers/char/ip2/ip2base.c.
  773. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  774. See header of drivers/scsi/ips.c.
  775. irqfixup [HW]
  776. When an interrupt is not handled search all handlers
  777. for it. Intended to get systems with badly broken
  778. firmware running.
  779. irqpoll [HW]
  780. When an interrupt is not handled search all handlers
  781. for it. Also check all handlers each timer
  782. interrupt. Intended to get systems with badly broken
  783. firmware running.
  784. isapnp= [ISAPNP]
  785. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  786. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  787. Format:
  788. <cpu number>,...,<cpu number>
  789. or
  790. <cpu number>-<cpu number>
  791. (must be a positive range in ascending order)
  792. or a mixture
  793. <cpu number>,...,<cpu number>-<cpu number>
  794. This option can be used to specify one or more CPUs
  795. to isolate from the general SMP balancing and scheduling
  796. algorithms. You can move a process onto or off an
  797. "isolated" CPU via the CPU affinity syscalls or cpuset.
  798. <cpu number> begins at 0 and the maximum value is
  799. "number of CPUs in system - 1".
  800. This option is the preferred way to isolate CPUs. The
  801. alternative -- manually setting the CPU mask of all
  802. tasks in the system -- can cause problems and
  803. suboptimal load balancer performance.
  804. iucv= [HW,NET]
  805. js= [HW,JOY] Analog joystick
  806. See Documentation/input/joystick.txt.
  807. keepinitrd [HW,ARM]
  808. kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  809. specifies the amount of memory usable by the kernel
  810. for non-movable allocations. The requested amount is
  811. spread evenly throughout all nodes in the system. The
  812. remaining memory in each node is used for Movable
  813. pages. In the event, a node is too small to have both
  814. kernelcore and Movable pages, kernelcore pages will
  815. take priority and other nodes will have a larger number
  816. of kernelcore pages. The Movable zone is used for the
  817. allocation of pages that may be reclaimed or moved
  818. by the page migration subsystem. This means that
  819. HugeTLB pages may not be allocated from this zone.
  820. Note that allocations like PTEs-from-HighMem still
  821. use the HighMem zone if it exists, and the Normal
  822. zone if it does not.
  823. kmemtrace.enable= [KNL,KMEMTRACE] Format: { yes | no }
  824. Controls whether kmemtrace is enabled
  825. at boot-time.
  826. kmemtrace.subbufs=n [KNL,KMEMTRACE] Overrides the number of
  827. subbufs kmemtrace's relay channel has. Set this
  828. higher than default (KMEMTRACE_N_SUBBUFS in code) if
  829. you experience buffer overruns.
  830. kgdboc= [HW] kgdb over consoles.
  831. Requires a tty driver that supports console polling.
  832. (only serial suported for now)
  833. Format: <serial_device>[,baud]
  834. kmac= [MIPS] korina ethernet MAC address.
  835. Configure the RouterBoard 532 series on-chip
  836. Ethernet adapter MAC address.
  837. kstack=N [X86-32,X86-64] Print N words from the kernel stack
  838. in oops dumps.
  839. l2cr= [PPC]
  840. l3cr= [PPC]
  841. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  842. disabled it.
  843. lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer
  844. in C2 power state.
  845. libata.dma= [LIBATA] DMA control
  846. libata.dma=0 Disable all PATA and SATA DMA
  847. libata.dma=1 PATA and SATA Disk DMA only
  848. libata.dma=2 ATAPI (CDROM) DMA only
  849. libata.dma=4 Compact Flash DMA only
  850. Combinations also work, so libata.dma=3 enables DMA
  851. for disks and CDROMs, but not CFs.
  852. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  853. when set.
  854. Format: <int>
  855. libata.force= [LIBATA] Force configurations. The format is comma
  856. separated list of "[ID:]VAL" where ID is
  857. PORT[:DEVICE]. PORT and DEVICE are decimal numbers
  858. matching port, link or device. Basically, it matches
  859. the ATA ID string printed on console by libata. If
  860. the whole ID part is omitted, the last PORT and DEVICE
  861. values are used. If ID hasn't been specified yet, the
  862. configuration applies to all ports, links and devices.
  863. If only DEVICE is omitted, the parameter applies to
  864. the port and all links and devices behind it. DEVICE
  865. number of 0 either selects the first device or the
  866. first fan-out link behind PMP device. It does not
  867. select the host link. DEVICE number of 15 selects the
  868. host link and device attached to it.
  869. The VAL specifies the configuration to force. As long
  870. as there's no ambiguity shortcut notation is allowed.
  871. For example, both 1.5 and 1.5G would work for 1.5Gbps.
  872. The following configurations can be forced.
  873. * Cable type: 40c, 80c, short40c, unk, ign or sata.
  874. Any ID with matching PORT is used.
  875. * SATA link speed limit: 1.5Gbps or 3.0Gbps.
  876. * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
  877. udma[/][16,25,33,44,66,100,133] notation is also
  878. allowed.
  879. * [no]ncq: Turn on or off NCQ.
  880. * nohrst, nosrst, norst: suppress hard, soft
  881. and both resets.
  882. If there are multiple matching configurations changing
  883. the same attribute, the last one is used.
  884. lmb=debug [KNL] Enable lmb debug messages.
  885. load_ramdisk= [RAM] List of ramdisks to load from floppy
  886. See Documentation/blockdev/ramdisk.txt.
  887. lockd.nlm_grace_period=P [NFS] Assign grace period.
  888. Format: <integer>
  889. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  890. Format: <integer>
  891. lockd.nlm_timeout=T [NFS] Assign timeout value.
  892. Format: <integer>
  893. lockd.nlm_udpport=M [NFS] Assign UDP port.
  894. Format: <integer>
  895. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  896. Format: <irq>
  897. loglevel= All Kernel Messages with a loglevel smaller than the
  898. console loglevel will be printed to the console. It can
  899. also be changed with klogd or other programs. The
  900. loglevels are defined as follows:
  901. 0 (KERN_EMERG) system is unusable
  902. 1 (KERN_ALERT) action must be taken immediately
  903. 2 (KERN_CRIT) critical conditions
  904. 3 (KERN_ERR) error conditions
  905. 4 (KERN_WARNING) warning conditions
  906. 5 (KERN_NOTICE) normal but significant condition
  907. 6 (KERN_INFO) informational
  908. 7 (KERN_DEBUG) debug-level messages
  909. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  910. Format: { n | nk | nM }
  911. n must be a power of two. The default size
  912. is set in the kernel config file.
  913. logo.nologo [FB] Disables display of the built-in Linux logo.
  914. This may be used to provide more screen space for
  915. kernel log messages and is useful when debugging
  916. kernel boot problems.
  917. lp=0 [LP] Specify parallel ports to use, e.g,
  918. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  919. lp=reset first parallel port). 'lp=0' disables the
  920. lp=auto printer driver. 'lp=reset' (which can be
  921. specified in addition to the ports) causes
  922. attached printers to be reset. Using
  923. lp=port1,port2,... specifies the parallel ports
  924. to associate lp devices with, starting with
  925. lp0. A port specification may be 'none' to skip
  926. that lp device, or a parport name such as
  927. 'parport0'. Specifying 'lp=auto' instead of a
  928. port specification list means that device IDs
  929. from each port should be examined, to see if
  930. an IEEE 1284-compliant printer is attached; if
  931. so, the driver will manage that printer.
  932. See also header of drivers/char/lp.c.
  933. lpj=n [KNL]
  934. Sets loops_per_jiffy to given constant, thus avoiding
  935. time-consuming boot-time autodetection (up to 250 ms per
  936. CPU). 0 enables autodetection (default). To determine
  937. the correct value for your kernel, boot with normal
  938. autodetection and see what value is printed. Note that
  939. on SMP systems the preset will be applied to all CPUs,
  940. which is likely to cause problems if your CPUs need
  941. significantly divergent settings. An incorrect value
  942. will cause delays in the kernel to be wrong, leading to
  943. unpredictable I/O errors and other breakage. Although
  944. unlikely, in the extreme case this might damage your
  945. hardware.
  946. ltpc= [NET]
  947. Format: <io>,<irq>,<dma>
  948. mac5380= [HW,SCSI] Format:
  949. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  950. machvec= [IA64] Force the use of a particular machine-vector
  951. (machvec) in a generic kernel.
  952. Example: machvec=hpzx1_swiotlb
  953. max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
  954. than or equal to this physical address is ignored.
  955. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  956. should make use of. maxcpus=n : n >= 0 limits the
  957. kernel to using 'n' processors. n=0 is a special case,
  958. it is equivalent to "nosmp", which also disables
  959. the IO APIC.
  960. max_loop= [LOOP] Maximum number of loopback devices that can
  961. be mounted
  962. Format: <1-256>
  963. max_luns= [SCSI] Maximum number of LUNs to probe.
  964. Should be between 1 and 2^32-1.
  965. max_report_luns=
  966. [SCSI] Maximum number of LUNs received.
  967. Should be between 1 and 16384.
  968. mcatest= [IA-64]
  969. mce [X86-32] Machine Check Exception
  970. mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
  971. md= [HW] RAID subsystems devices and level
  972. See Documentation/md.txt.
  973. mdacon= [MDA]
  974. Format: <first>,<last>
  975. Specifies range of consoles to be captured by the MDA.
  976. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  977. Amount of memory to be used when the kernel is not able
  978. to see the whole system memory or for test.
  979. [X86-32] Use together with memmap= to avoid physical
  980. address space collisions. Without memmap= PCI devices
  981. could be placed at addresses belonging to unused RAM.
  982. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  983. memory.
  984. memchunk=nn[KMG]
  985. [KNL,SH] Allow user to override the default size for
  986. per-device physically contiguous DMA buffers.
  987. memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
  988. E820 memory map, as specified by the user.
  989. Such memmap=exactmap lines can be constructed based on
  990. BIOS output or other requirements. See the memmap=nn@ss
  991. option description.
  992. memmap=nn[KMG]@ss[KMG]
  993. [KNL] Force usage of a specific region of memory
  994. Region of memory to be used, from ss to ss+nn.
  995. memmap=nn[KMG]#ss[KMG]
  996. [KNL,ACPI] Mark specific memory as ACPI data.
  997. Region of memory to be used, from ss to ss+nn.
  998. memmap=nn[KMG]$ss[KMG]
  999. [KNL,ACPI] Mark specific memory as reserved.
  1000. Region of memory to be used, from ss to ss+nn.
  1001. Example: Exclude memory from 0x18690000-0x1869ffff
  1002. memmap=64K$0x18690000
  1003. or
  1004. memmap=0x10000$0x18690000
  1005. memory_corruption_check=0/1 [X86]
  1006. Some BIOSes seem to corrupt the first 64k of
  1007. memory when doing things like suspend/resume.
  1008. Setting this option will scan the memory
  1009. looking for corruption. Enabling this will
  1010. both detect corruption and prevent the kernel
  1011. from using the memory being corrupted.
  1012. However, its intended as a diagnostic tool; if
  1013. repeatable BIOS-originated corruption always
  1014. affects the same memory, you can use memmap=
  1015. to prevent the kernel from using that memory.
  1016. memory_corruption_check_size=size [X86]
  1017. By default it checks for corruption in the low
  1018. 64k, making this memory unavailable for normal
  1019. use. Use this parameter to scan for
  1020. corruption in more or less memory.
  1021. memory_corruption_check_period=seconds [X86]
  1022. By default it checks for corruption every 60
  1023. seconds. Use this parameter to check at some
  1024. other rate. 0 disables periodic checking.
  1025. memtest= [KNL,X86] Enable memtest
  1026. Format: <integer>
  1027. default : 0 <disable>
  1028. Specifies the number of memtest passes to be
  1029. performed. Each pass selects another test
  1030. pattern from a given set of patterns. Memtest
  1031. fills the memory with this pattern, validates
  1032. memory contents and reserves bad memory
  1033. regions that are detected.
  1034. meye.*= [HW] Set MotionEye Camera parameters
  1035. See Documentation/video4linux/meye.txt.
  1036. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  1037. Multi-Function General Purpose Timers on AMD Geode
  1038. platforms.
  1039. mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
  1040. the BIOS has incorrectly applied a workaround. TinyBIOS
  1041. version 0.98 is known to be affected, 0.99 fixes the
  1042. problem by letting the user disable the workaround.
  1043. mga= [HW,DRM]
  1044. min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
  1045. physical address is ignored.
  1046. mminit_loglevel=
  1047. [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
  1048. parameter allows control of the logging verbosity for
  1049. the additional memory initialisation checks. A value
  1050. of 0 disables mminit logging and a level of 4 will
  1051. log everything. Information is printed at KERN_DEBUG
  1052. so loglevel=8 may also need to be specified.
  1053. mousedev.tap_time=
  1054. [MOUSE] Maximum time between finger touching and
  1055. leaving touchpad surface for touch to be considered
  1056. a tap and be reported as a left button click (for
  1057. touchpads working in absolute mode only).
  1058. Format: <msecs>
  1059. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  1060. reporting absolute coordinates, such as tablets
  1061. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  1062. reporting absolute coordinates, such as tablets
  1063. movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  1064. is similar to kernelcore except it specifies the
  1065. amount of memory used for migratable allocations.
  1066. If both kernelcore and movablecore is specified,
  1067. then kernelcore will be at *least* the specified
  1068. value but may be more. If movablecore on its own
  1069. is specified, the administrator must be careful
  1070. that the amount of memory usable for all allocations
  1071. is not too small.
  1072. mpu401= [HW,OSS]
  1073. Format: <io>,<irq>
  1074. MTD_Partition= [MTD]
  1075. Format: <name>,<region-number>,<size>,<offset>
  1076. MTD_Region= [MTD] Format:
  1077. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  1078. mtdparts= [MTD]
  1079. See drivers/mtd/cmdlinepart.c.
  1080. mtdset= [ARM]
  1081. ARM/S3C2412 JIVE boot control
  1082. See arch/arm/mach-s3c2412/mach-jive.c
  1083. mtouchusb.raw_coordinates=
  1084. [HW] Make the MicroTouch USB driver use raw coordinates
  1085. ('y', default) or cooked coordinates ('n')
  1086. mtrr_chunk_size=nn[KMG] [X86]
  1087. used for mtrr cleanup. It is largest continous chunk
  1088. that could hold holes aka. UC entries.
  1089. mtrr_gran_size=nn[KMG] [X86]
  1090. Used for mtrr cleanup. It is granularity of mtrr block.
  1091. Default is 1.
  1092. Large value could prevent small alignment from
  1093. using up MTRRs.
  1094. mtrr_spare_reg_nr=n [X86]
  1095. Format: <integer>
  1096. Range: 0,7 : spare reg number
  1097. Default : 1
  1098. Used for mtrr cleanup. It is spare mtrr entries number.
  1099. Set to 2 or more if your graphical card needs more.
  1100. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  1101. NCR_D700= [HW,SCSI]
  1102. See header of drivers/scsi/NCR_D700.c.
  1103. ncr5380= [HW,SCSI]
  1104. ncr53c400= [HW,SCSI]
  1105. ncr53c400a= [HW,SCSI]
  1106. ncr53c406a= [HW,SCSI]
  1107. ncr53c8xx= [HW,SCSI]
  1108. netdev= [NET] Network devices parameters
  1109. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  1110. Note that mem_start is often overloaded to mean
  1111. something different and driver-specific.
  1112. This usage is only documented in each driver source
  1113. file if at all.
  1114. nf_conntrack.acct=
  1115. [NETFILTER] Enable connection tracking flow accounting
  1116. 0 to disable accounting
  1117. 1 to enable accounting
  1118. Default value depends on CONFIG_NF_CT_ACCT that is
  1119. going to be removed in 2.6.29.
  1120. nfsaddrs= [NFS]
  1121. See Documentation/filesystems/nfsroot.txt.
  1122. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  1123. See Documentation/filesystems/nfsroot.txt.
  1124. nfs.callback_tcpport=
  1125. [NFS] set the TCP port on which the NFSv4 callback
  1126. channel should listen.
  1127. nfs.idmap_cache_timeout=
  1128. [NFS] set the maximum lifetime for idmapper cache
  1129. entries.
  1130. nfs.enable_ino64=
  1131. [NFS] enable 64-bit inode numbers.
  1132. If zero, the NFS client will fake up a 32-bit inode
  1133. number for the readdir() and stat() syscalls instead
  1134. of returning the full 64-bit number.
  1135. The default is to return 64-bit inode numbers.
  1136. nmi_debug= [KNL,AVR32] Specify one or more actions to take
  1137. when a NMI is triggered.
  1138. Format: [state][,regs][,debounce][,die]
  1139. nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
  1140. Format: [panic,][num]
  1141. Valid num: 0,1,2
  1142. 0 - turn nmi_watchdog off
  1143. 1 - use the IO-APIC timer for the NMI watchdog
  1144. 2 - use the local APIC for the NMI watchdog using
  1145. a performance counter. Note: This will use one
  1146. performance counter and the local APIC's performance
  1147. vector.
  1148. When panic is specified, panic when an NMI watchdog
  1149. timeout occurs.
  1150. This is useful when you use a panic=... timeout and
  1151. need the box quickly up again.
  1152. Instead of 1 and 2 it is possible to use the following
  1153. symbolic names: lapic and ioapic
  1154. Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
  1155. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  1156. emulation library even if a 387 maths coprocessor
  1157. is present.
  1158. no_console_suspend
  1159. [HW] Never suspend the console
  1160. Disable suspending of consoles during suspend and
  1161. hibernate operations. Once disabled, debugging
  1162. messages can reach various consoles while the rest
  1163. of the system is being put to sleep (ie, while
  1164. debugging driver suspend/resume hooks). This may
  1165. not work reliably with all consoles, but is known
  1166. to work with serial and VGA consoles.
  1167. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  1168. caches in the slab allocator. Saves per-node memory,
  1169. but will impact performance.
  1170. noalign [KNL,ARM]
  1171. noapic [SMP,APIC] Tells the kernel to not make use of any
  1172. IOAPICs that may be present in the system.
  1173. nobats [PPC] Do not use BATs for mapping kernel lowmem
  1174. on "Classic" PPC cores.
  1175. nocache [ARM]
  1176. noclflush [BUGS=X86] Don't use the CLFLUSH instruction
  1177. nodelayacct [KNL] Disable per-task delay accounting
  1178. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  1179. nodsp [SH] Disable hardware DSP at boot time.
  1180. noefi [X86-32,X86-64] Disable EFI runtime services support.
  1181. noexec [IA-64]
  1182. noexec [X86-32,X86-64]
  1183. On X86-32 available only on PAE configured kernels.
  1184. noexec=on: enable non-executable mappings (default)
  1185. noexec=off: disable non-executable mappings
  1186. noexec32 [X86-64]
  1187. This affects only 32-bit executables.
  1188. noexec32=on: enable non-executable mappings (default)
  1189. read doesn't imply executable mappings
  1190. noexec32=off: disable non-executable mappings
  1191. read implies executable mappings
  1192. nofpu [SH] Disable hardware FPU at boot time.
  1193. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  1194. register save and restore. The kernel will only save
  1195. legacy floating-point registers on task switch.
  1196. nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
  1197. wfi(ARM) instruction doesn't work correctly and not to
  1198. use it. This is also useful when using JTAG debugger.
  1199. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  1200. instruction doesn't work correctly and not to
  1201. use it.
  1202. no_file_caps Tells the kernel not to honor file capabilities. The
  1203. only way then for a file to be executed with privilege
  1204. is to be setuid root or executed by root.
  1205. nohalt [IA-64] Tells the kernel not to use the power saving
  1206. function PAL_HALT_LIGHT when idle. This increases
  1207. power-consumption. On the positive side, it reduces
  1208. interrupt wake-up latency, which may improve performance
  1209. in certain environments such as networked servers or
  1210. real-time systems.
  1211. nohz= [KNL] Boottime enable/disable dynamic ticks
  1212. Valid arguments: on, off
  1213. Default: on
  1214. noiotrap [SH] Disables trapped I/O port accesses.
  1215. noirqdebug [X86-32] Disables the code which attempts to detect and
  1216. disable unhandled interrupt sources.
  1217. no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
  1218. broken timer IRQ sources.
  1219. noisapnp [ISAPNP] Disables ISA PnP code.
  1220. noinitrd [RAM] Tells the kernel not to load any configured
  1221. initial RAM disk.
  1222. nointroute [IA-64]
  1223. nojitter [IA64] Disables jitter checking for ITC timers.
  1224. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  1225. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  1226. noltlbs [PPC] Do not use large page/tlb entries for kernel
  1227. lowmem mapping on PPC40x.
  1228. nomca [IA-64] Disable machine check abort handling
  1229. nomce [X86-32] Machine Check Exception
  1230. nomfgpt [X86-32] Disable Multi-Function General Purpose
  1231. Timer usage (for AMD Geode machines).
  1232. norandmaps Don't use address space randomization. Equivalent to
  1233. echo 0 > /proc/sys/kernel/randomize_va_space
  1234. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  1235. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  1236. with UP alternatives
  1237. noresidual [PPC] Don't use residual data on PReP machines.
  1238. noresume [SWSUSP] Disables resume and restores original swap
  1239. space.
  1240. no-scroll [VGA] Disables scrollback.
  1241. This is required for the Braillex ib80-piezo Braille
  1242. reader made by F.H. Papenmeier (Germany).
  1243. nosbagart [IA-64]
  1244. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  1245. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  1246. and disable the IO APIC. legacy for "maxcpus=0".
  1247. nosoftlockup [KNL] Disable the soft-lockup detector.
  1248. noswapaccount [KNL] Disable accounting of swap in memory resource
  1249. controller. (See Documentation/cgroups/memory.txt)
  1250. nosync [HW,M68K] Disables sync negotiation for all devices.
  1251. notsc [BUGS=X86-32] Disable Time Stamp Counter
  1252. nousb [USB] Disable the USB subsystem
  1253. nowb [ARM]
  1254. nptcg= [IA64] Override max number of concurrent global TLB
  1255. purges which is reported from either PAL_VM_SUMMARY or
  1256. SAL PALO.
  1257. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  1258. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  1259. one of ['zone', 'node', 'default'] can be specified
  1260. This can be set from sysctl after boot.
  1261. See Documentation/sysctl/vm.txt for details.
  1262. ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
  1263. See Documentation/debugging-via-ohci1394.txt for more
  1264. info.
  1265. olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
  1266. Rather than timing out after 20 ms if an EC
  1267. command is not properly ACKed, override the length
  1268. of the timeout. We have interrupts disabled while
  1269. waiting for the ACK, so if this is set too high
  1270. interrupts *may* be lost!
  1271. opl3= [HW,OSS]
  1272. Format: <io>
  1273. oprofile.timer= [HW]
  1274. Use timer interrupt instead of performance counters
  1275. osst= [HW,SCSI] SCSI Tape Driver
  1276. Format: <buffer_size>,<write_threshold>
  1277. See also Documentation/scsi/st.txt.
  1278. panic= [KNL] Kernel behaviour on panic
  1279. Format: <timeout>
  1280. parkbd.port= [HW] Parallel port number the keyboard adapter is
  1281. connected to, default is 0.
  1282. Format: <parport#>
  1283. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  1284. 0 for XT, 1 for AT (default is AT).
  1285. Format: <mode>
  1286. parport= [HW,PPT] Specify parallel ports. 0 disables.
  1287. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  1288. Use 'auto' to force the driver to use any
  1289. IRQ/DMA settings detected (the default is to
  1290. ignore detected IRQ/DMA settings because of
  1291. possible conflicts). You can specify the base
  1292. address, IRQ, and DMA settings; IRQ and DMA
  1293. should be numbers, or 'auto' (for using detected
  1294. settings on that particular port), or 'nofifo'
  1295. (to avoid using a FIFO even if it is detected).
  1296. Parallel ports are assigned in the order they
  1297. are specified on the command line, starting
  1298. with parport0.
  1299. parport_init_mode= [HW,PPT]
  1300. Configure VIA parallel port to operate in
  1301. a specific mode. This is necessary on Pegasos
  1302. computer where firmware has no options for setting
  1303. up parallel port mode and sets it to spp.
  1304. Currently this function knows 686a and 8231 chips.
  1305. Format: [spp|ps2|epp|ecp|ecpepp]
  1306. pas2= [HW,OSS] Format:
  1307. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  1308. pas16= [HW,SCSI]
  1309. See header of drivers/scsi/pas16.c.
  1310. pause_on_oops=
  1311. Halt all CPUs after the first oops has been printed for
  1312. the specified number of seconds. This is to be used if
  1313. your oopses keep scrolling off the screen.
  1314. pcbit= [HW,ISDN]
  1315. pcd. [PARIDE]
  1316. See header of drivers/block/paride/pcd.c.
  1317. See also Documentation/blockdev/paride.txt.
  1318. pci=option[,option...] [PCI] various PCI subsystem options:
  1319. earlydump [X86] dump PCI config space before the kernel
  1320. changes anything
  1321. off [X86] don't probe for the PCI bus
  1322. bios [X86-32] force use of PCI BIOS, don't access
  1323. the hardware directly. Use this if your machine
  1324. has a non-standard PCI host bridge.
  1325. nobios [X86-32] disallow use of PCI BIOS, only direct
  1326. hardware access methods are allowed. Use this
  1327. if you experience crashes upon bootup and you
  1328. suspect they are caused by the BIOS.
  1329. conf1 [X86] Force use of PCI Configuration
  1330. Mechanism 1.
  1331. conf2 [X86] Force use of PCI Configuration
  1332. Mechanism 2.
  1333. noaer [PCIE] If the PCIEAER kernel config parameter is
  1334. enabled, this kernel boot option can be used to
  1335. disable the use of PCIE advanced error reporting.
  1336. nodomains [PCI] Disable support for multiple PCI
  1337. root domains (aka PCI segments, in ACPI-speak).
  1338. nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
  1339. Configuration
  1340. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1341. enabled, this kernel boot option can be used to
  1342. disable the use of MSI interrupts system-wide.
  1343. noioapicquirk [APIC] Disable all boot interrupt quirks.
  1344. Safety option to keep boot IRQs enabled. This
  1345. should never be necessary.
  1346. ioapicreroute [APIC] Enable rerouting of boot IRQs to the
  1347. primary IO-APIC for bridges that cannot disable
  1348. boot IRQs. This fixes a source of spurious IRQs
  1349. when the system masks IRQs.
  1350. noioapicreroute [APIC] Disable workaround that uses the
  1351. boot IRQ equivalent of an IRQ that connects to
  1352. a chipset where boot IRQs cannot be disabled.
  1353. The opposite of ioapicreroute.
  1354. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1355. routing table. These calls are known to be buggy
  1356. on several machines and they hang the machine
  1357. when used, but on other computers it's the only
  1358. way to get the interrupt routing table. Try
  1359. this option if the kernel is unable to allocate
  1360. IRQs or discover secondary PCI buses on your
  1361. motherboard.
  1362. rom [X86] Assign address space to expansion ROMs.
  1363. Use with caution as certain devices share
  1364. address decoders between ROMs and other
  1365. resources.
  1366. norom [X86] Do not assign address space to
  1367. expansion ROMs that do not already have
  1368. BIOS assigned address ranges.
  1369. irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
  1370. assigned automatically to PCI devices. You can
  1371. make the kernel exclude IRQs of your ISA cards
  1372. this way.
  1373. pirqaddr=0xAAAAA [X86] Specify the physical address
  1374. of the PIRQ table (normally generated
  1375. by the BIOS) if it is outside the
  1376. F0000h-100000h range.
  1377. lastbus=N [X86] Scan all buses thru bus #N. Can be
  1378. useful if the kernel is unable to find your
  1379. secondary buses and you want to tell it
  1380. explicitly which ones they are.
  1381. assign-busses [X86] Always assign all PCI bus
  1382. numbers ourselves, overriding
  1383. whatever the firmware may have done.
  1384. usepirqmask [X86] Honor the possible IRQ mask stored
  1385. in the BIOS $PIR table. This is needed on
  1386. some systems with broken BIOSes, notably
  1387. some HP Pavilion N5400 and Omnibook XE3
  1388. notebooks. This will have no effect if ACPI
  1389. IRQ routing is enabled.
  1390. noacpi [X86] Do not use ACPI for IRQ routing
  1391. or for PCI scanning.
  1392. use_crs [X86] Use _CRS for PCI resource
  1393. allocation.
  1394. routeirq Do IRQ routing for all PCI devices.
  1395. This is normally done in pci_enable_device(),
  1396. so this option is a temporary workaround
  1397. for broken drivers that don't call it.
  1398. skip_isa_align [X86] do not align io start addr, so can
  1399. handle more pci cards
  1400. firmware [ARM] Do not re-enumerate the bus but instead
  1401. just use the configuration from the
  1402. bootloader. This is currently used on
  1403. IXP2000 systems where the bus has to be
  1404. configured a certain way for adjunct CPUs.
  1405. noearly [X86] Don't do any early type 1 scanning.
  1406. This might help on some broken boards which
  1407. machine check when some devices' config space
  1408. is read. But various workarounds are disabled
  1409. and some IOMMU drivers will not work.
  1410. bfsort Sort PCI devices into breadth-first order.
  1411. This sorting is done to get a device
  1412. order compatible with older (<= 2.4) kernels.
  1413. nobfsort Don't sort PCI devices into breadth-first order.
  1414. cbiosize=nn[KMG] The fixed amount of bus space which is
  1415. reserved for the CardBus bridge's IO window.
  1416. The default value is 256 bytes.
  1417. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1418. reserved for the CardBus bridge's memory
  1419. window. The default value is 64 megabytes.
  1420. resource_alignment=
  1421. Format:
  1422. [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
  1423. Specifies alignment and device to reassign
  1424. aligned memory resources.
  1425. If <order of align> is not specified,
  1426. PAGE_SIZE is used as alignment.
  1427. PCI-PCI bridge can be specified, if resource
  1428. windows need to be expanded.
  1429. pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
  1430. Management.
  1431. off Disable ASPM.
  1432. force Enable ASPM even on devices that claim not to support it.
  1433. WARNING: Forcing ASPM on may cause system lockups.
  1434. pcmv= [HW,PCMCIA] BadgePAD 4
  1435. pd. [PARIDE]
  1436. See Documentation/blockdev/paride.txt.
  1437. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1438. boot time.
  1439. Format: { 0 | 1 }
  1440. See arch/parisc/kernel/pdc_chassis.c
  1441. pf. [PARIDE]
  1442. See Documentation/blockdev/paride.txt.
  1443. pg. [PARIDE]
  1444. See Documentation/blockdev/paride.txt.
  1445. pirq= [SMP,APIC] Manual mp-table setup
  1446. See Documentation/x86/i386/IO-APIC.txt.
  1447. plip= [PPT,NET] Parallel port network link
  1448. Format: { parport<nr> | timid | 0 }
  1449. See also Documentation/parport.txt.
  1450. pmtmr= [X86] Manual setup of pmtmr I/O Port.
  1451. Override pmtimer IOPort with a hex value.
  1452. e.g. pmtmr=0x508
  1453. pnp.debug [PNP]
  1454. Enable PNP debug messages. This depends on the
  1455. CONFIG_PNP_DEBUG_MESSAGES option.
  1456. pnpacpi= [ACPI]
  1457. { off }
  1458. pnpbios= [ISAPNP]
  1459. { on | off | curr | res | no-curr | no-res }
  1460. pnp_reserve_irq=
  1461. [ISAPNP] Exclude IRQs for the autoconfiguration
  1462. pnp_reserve_dma=
  1463. [ISAPNP] Exclude DMAs for the autoconfiguration
  1464. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1465. Ranges are in pairs (I/O port base and size).
  1466. pnp_reserve_mem=
  1467. [ISAPNP] Exclude memory regions for the
  1468. autoconfiguration.
  1469. Ranges are in pairs (memory base and size).
  1470. print-fatal-signals=
  1471. [KNL] debug: print fatal signals
  1472. print-fatal-signals=1: print segfault info to
  1473. the kernel console.
  1474. default: off.
  1475. printk.time= Show timing data prefixed to each printk message line
  1476. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1477. processor.max_cstate= [HW,ACPI]
  1478. Limit processor to maximum C-state
  1479. max_cstate=9 overrides any DMI blacklist limit.
  1480. processor.nocst [HW,ACPI]
  1481. Ignore the _CST method to determine C-states,
  1482. instead using the legacy FADT method
  1483. profile= [KNL] Enable kernel profiling via /proc/profile
  1484. Format: [schedule,]<number>
  1485. Param: "schedule" - profile schedule points.
  1486. Param: <number> - step/bucket size as a power of 2 for
  1487. statistical time based profiling.
  1488. Param: "sleep" - profile D-state sleeping (millisecs).
  1489. Requires CONFIG_SCHEDSTATS
  1490. Param: "kvm" - profile VM exits.
  1491. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1492. before loading.
  1493. See Documentation/blockdev/ramdisk.txt.
  1494. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1495. probe for; one of (bare|imps|exps|lifebook|any).
  1496. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1497. per second.
  1498. psmouse.resetafter= [HW,MOUSE]
  1499. Try to reset the device after so many bad packets
  1500. (0 = never).
  1501. psmouse.resolution=
  1502. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1503. psmouse.smartscroll=
  1504. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1505. 0 = disabled, 1 = enabled (default).
  1506. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1507. Format:
  1508. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1509. pt. [PARIDE]
  1510. See Documentation/blockdev/paride.txt.
  1511. pty.legacy_count=
  1512. [KNL] Number of legacy pty's. Overwrites compiled-in
  1513. default number.
  1514. quiet [KNL] Disable most log messages
  1515. r128= [HW,DRM]
  1516. raid= [HW,RAID]
  1517. See Documentation/md.txt.
  1518. ramdisk_blocksize= [RAM]
  1519. See Documentation/blockdev/ramdisk.txt.
  1520. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1521. See Documentation/blockdev/ramdisk.txt.
  1522. rcupdate.blimit= [KNL,BOOT]
  1523. Set maximum number of finished RCU callbacks to process
  1524. in one batch.
  1525. rcupdate.qhimark= [KNL,BOOT]
  1526. Set threshold of queued
  1527. RCU callbacks over which batch limiting is disabled.
  1528. rcupdate.qlowmark= [KNL,BOOT]
  1529. Set threshold of queued RCU callbacks below which
  1530. batch limiting is re-enabled.
  1531. rdinit= [KNL]
  1532. Format: <full_path>
  1533. Run specified binary instead of /init from the ramdisk,
  1534. used for early userspace startup. See initrd.
  1535. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1536. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1537. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1538. relax_domain_level=
  1539. [KNL, SMP] Set scheduler's default relax_domain_level.
  1540. See Documentation/cgroups/cpusets.txt.
  1541. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1542. reservetop= [X86-32]
  1543. Format: nn[KMG]
  1544. Reserves a hole at the top of the kernel virtual
  1545. address space.
  1546. reset_devices [KNL] Force drivers to reset the underlying device
  1547. during initialization.
  1548. resume= [SWSUSP]
  1549. Specify the partition device for software suspend
  1550. resume_offset= [SWSUSP]
  1551. Specify the offset from the beginning of the partition
  1552. given by "resume=" at which the swap header is located,
  1553. in <PAGE_SIZE> units (needed only for swap files).
  1554. See Documentation/power/swsusp-and-swap-files.txt
  1555. retain_initrd [RAM] Keep initrd memory after extraction
  1556. rhash_entries= [KNL,NET]
  1557. Set number of hash buckets for route cache
  1558. riscom8= [HW,SERIAL]
  1559. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1560. ro [KNL] Mount root device read-only on boot
  1561. root= [KNL] Root filesystem
  1562. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1563. mount the root filesystem
  1564. rootflags= [KNL] Set root filesystem mount option string
  1565. rootfstype= [KNL] Set root filesystem type
  1566. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1567. Useful for devices that are detected asynchronously
  1568. (e.g. USB and MMC devices).
  1569. root_plug.vendor_id=
  1570. [ROOTPLUG] Override the default vendor ID
  1571. root_plug.product_id=
  1572. [ROOTPLUG] Override the default product ID
  1573. root_plug.debug=
  1574. [ROOTPLUG] Enable debugging output
  1575. rw [KNL] Mount root device read-write on boot
  1576. S [KNL] Run init in single mode
  1577. sa1100ir [NET]
  1578. See drivers/net/irda/sa1100_ir.c.
  1579. sbni= [NET] Granch SBNI12 leased line adapter
  1580. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1581. Format: <io>[,<timeout>[,<isapnp>]]
  1582. scsi_debug_*= [SCSI]
  1583. See drivers/scsi/scsi_debug.c.
  1584. scsi_default_dev_flags=
  1585. [SCSI] SCSI default device flags
  1586. Format: <integer>
  1587. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1588. Format: <vendor>:<model>:<flags>
  1589. (flags are integer value)
  1590. scsi_logging_level= [SCSI] a bit mask of logging levels
  1591. See drivers/scsi/scsi_logging.h for bits. Also
  1592. settable via sysctl at dev.scsi.logging_level
  1593. (/proc/sys/dev/scsi/logging_level).
  1594. There is also a nice 'scsi_logging_level' script in the
  1595. S390-tools package, available for download at
  1596. http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
  1597. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1598. discovered. async scans them in kernel threads,
  1599. allowing boot to proceed. none ignores them, expecting
  1600. user space to do the scan.
  1601. security= [SECURITY] Choose a security module to enable at boot.
  1602. If this boot parameter is not specified, only the first
  1603. security module asking for security registration will be
  1604. loaded. An invalid security module name will be treated
  1605. as if no module has been chosen.
  1606. selinux= [SELINUX] Disable or enable SELinux at boot time.
  1607. Format: { "0" | "1" }
  1608. See security/selinux/Kconfig help text.
  1609. 0 -- disable.
  1610. 1 -- enable.
  1611. Default value is set via kernel config option.
  1612. If enabled at boot time, /selinux/disable can be used
  1613. later to disable prior to initial policy load.
  1614. serialnumber [BUGS=X86-32]
  1615. shapers= [NET]
  1616. Maximal number of shapers.
  1617. show_msr= [x86] show boot-time MSR settings
  1618. Format: { <integer> }
  1619. Show boot-time (BIOS-initialized) MSR settings.
  1620. The parameter means the number of CPUs to show,
  1621. for example 1 means boot CPU only.
  1622. sim710= [SCSI,HW]
  1623. See header of drivers/scsi/sim710.c.
  1624. simeth= [IA-64]
  1625. simscsi=
  1626. slram= [HW,MTD]
  1627. slub_debug[=options[,slabs]] [MM, SLUB]
  1628. Enabling slub_debug allows one to determine the
  1629. culprit if slab objects become corrupted. Enabling
  1630. slub_debug can create guard zones around objects and
  1631. may poison objects when not in use. Also tracks the
  1632. last alloc / free. For more information see
  1633. Documentation/vm/slub.txt.
  1634. slub_max_order= [MM, SLUB]
  1635. Determines the maximum allowed order for slabs.
  1636. A high setting may cause OOMs due to memory
  1637. fragmentation. For more information see
  1638. Documentation/vm/slub.txt.
  1639. slub_min_objects= [MM, SLUB]
  1640. The minimum number of objects per slab. SLUB will
  1641. increase the slab order up to slub_max_order to
  1642. generate a sufficiently large slab able to contain
  1643. the number of objects indicated. The higher the number
  1644. of objects the smaller the overhead of tracking slabs
  1645. and the less frequently locks need to be acquired.
  1646. For more information see Documentation/vm/slub.txt.
  1647. slub_min_order= [MM, SLUB]
  1648. Determines the mininum page order for slabs. Must be
  1649. lower than slub_max_order.
  1650. For more information see Documentation/vm/slub.txt.
  1651. slub_nomerge [MM, SLUB]
  1652. Disable merging of slabs with similar size. May be
  1653. necessary if there is some reason to distinguish
  1654. allocs to different slabs. Debug options disable
  1655. merging on their own.
  1656. For more information see Documentation/vm/slub.txt.
  1657. smart2= [HW]
  1658. Format: <io1>[,<io2>[,...,<io8>]]
  1659. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1660. attempt to substitute SMP alternatives once at boot.
  1661. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1662. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1663. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1664. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1665. smsc-ircc2.ircc_irq= [HW] IRQ line
  1666. smsc-ircc2.ircc_dma= [HW] DMA channel
  1667. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1668. 0: Toshiba Satellite 1800 (GP data pin select)
  1669. 1: Fast pin select (default)
  1670. 2: ATC IRMode
  1671. snd-ad1816a= [HW,ALSA]
  1672. snd-ad1848= [HW,ALSA]
  1673. snd-ali5451= [HW,ALSA]
  1674. snd-als100= [HW,ALSA]
  1675. snd-als4000= [HW,ALSA]
  1676. snd-azt2320= [HW,ALSA]
  1677. snd-cmi8330= [HW,ALSA]
  1678. snd-cmipci= [HW,ALSA]
  1679. snd-cs4231= [HW,ALSA]
  1680. snd-cs4232= [HW,ALSA]
  1681. snd-cs4236= [HW,ALSA]
  1682. snd-cs4281= [HW,ALSA]
  1683. snd-cs46xx= [HW,ALSA]
  1684. snd-dt019x= [HW,ALSA]
  1685. snd-dummy= [HW,ALSA]
  1686. snd-emu10k1= [HW,ALSA]
  1687. snd-ens1370= [HW,ALSA]
  1688. snd-ens1371= [HW,ALSA]
  1689. snd-es968= [HW,ALSA]
  1690. snd-es1688= [HW,ALSA]
  1691. snd-es18xx= [HW,ALSA]
  1692. snd-es1938= [HW,ALSA]
  1693. snd-es1968= [HW,ALSA]
  1694. snd-fm801= [HW,ALSA]
  1695. snd-gusclassic= [HW,ALSA]
  1696. snd-gusextreme= [HW,ALSA]
  1697. snd-gusmax= [HW,ALSA]
  1698. snd-hdsp= [HW,ALSA]
  1699. snd-ice1712= [HW,ALSA]
  1700. snd-intel8x0= [HW,ALSA]
  1701. snd-interwave= [HW,ALSA]
  1702. snd-interwave-stb=
  1703. [HW,ALSA]
  1704. snd-korg1212= [HW,ALSA]
  1705. snd-maestro3= [HW,ALSA]
  1706. snd-mpu401= [HW,ALSA]
  1707. snd-mtpav= [HW,ALSA]
  1708. snd-nm256= [HW,ALSA]
  1709. snd-opl3sa2= [HW,ALSA]
  1710. snd-opti92x-ad1848=
  1711. [HW,ALSA]
  1712. snd-opti92x-cs4231=
  1713. [HW,ALSA]
  1714. snd-opti93x= [HW,ALSA]
  1715. snd-pmac= [HW,ALSA]
  1716. snd-rme32= [HW,ALSA]
  1717. snd-rme96= [HW,ALSA]
  1718. snd-rme9652= [HW,ALSA]
  1719. snd-sb8= [HW,ALSA]
  1720. snd-sb16= [HW,ALSA]
  1721. snd-sbawe= [HW,ALSA]
  1722. snd-serial= [HW,ALSA]
  1723. snd-sgalaxy= [HW,ALSA]
  1724. snd-sonicvibes= [HW,ALSA]
  1725. snd-sun-amd7930=
  1726. [HW,ALSA]
  1727. snd-sun-cs4231= [HW,ALSA]
  1728. snd-trident= [HW,ALSA]
  1729. snd-usb-audio= [HW,ALSA,USB]
  1730. snd-via82xx= [HW,ALSA]
  1731. snd-virmidi= [HW,ALSA]
  1732. snd-wavefront= [HW,ALSA]
  1733. snd-ymfpci= [HW,ALSA]
  1734. softlockup_panic=
  1735. [KNL] Should the soft-lockup detector generate panics.
  1736. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1737. See Documentation/sonypi.txt
  1738. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1739. See Documentation/serial/specialix.txt.
  1740. spia_io_base= [HW,MTD]
  1741. spia_fio_base=
  1742. spia_pedr=
  1743. spia_peddr=
  1744. sscape= [HW,OSS]
  1745. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1746. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1747. See Documentation/scsi/st.txt.
  1748. stacktrace [FTRACE]
  1749. Enabled the stack tracer on boot up.
  1750. sti= [PARISC,HW]
  1751. Format: <num>
  1752. Set the STI (builtin display/keyboard on the HP-PARISC
  1753. machines) console (graphic card) which should be used
  1754. as the initial boot-console.
  1755. See also comment in drivers/video/console/sticore.c.
  1756. sti_font= [HW]
  1757. See comment in drivers/video/console/sticore.c.
  1758. stifb= [HW]
  1759. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1760. sunrpc.pool_mode=
  1761. [NFS]
  1762. Control how the NFS server code allocates CPUs to
  1763. service thread pools. Depending on how many NICs
  1764. you have and where their interrupts are bound, this
  1765. option will affect which CPUs will do NFS serving.
  1766. Note: this parameter cannot be changed while the
  1767. NFS server is running.
  1768. auto the server chooses an appropriate mode
  1769. automatically using heuristics
  1770. global a single global pool contains all CPUs
  1771. percpu one pool for each CPU
  1772. pernode one pool for each NUMA node (equivalent
  1773. to global on non-NUMA machines)
  1774. swiotlb= [IA-64] Number of I/O TLB slabs
  1775. switches= [HW,M68k]
  1776. sym53c416= [HW,SCSI]
  1777. See header of drivers/scsi/sym53c416.c.
  1778. sysrq_always_enabled
  1779. [KNL]
  1780. Ignore sysrq setting - this boot parameter will
  1781. neutralize any effect of /proc/sys/kernel/sysrq.
  1782. Useful for debugging.
  1783. t128= [HW,SCSI]
  1784. See header of drivers/scsi/t128.c.
  1785. tdfx= [HW,DRM]
  1786. test_suspend= [SUSPEND]
  1787. Specify "mem" (for Suspend-to-RAM) or "standby" (for
  1788. standby suspend) as the system sleep state to briefly
  1789. enter during system startup. The system is woken from
  1790. this state using a wakeup-capable RTC alarm.
  1791. thash_entries= [KNL,NET]
  1792. Set number of hash buckets for TCP connection
  1793. thermal.act= [HW,ACPI]
  1794. -1: disable all active trip points in all thermal zones
  1795. <degrees C>: override all lowest active trip points
  1796. thermal.crt= [HW,ACPI]
  1797. -1: disable all critical trip points in all thermal zones
  1798. <degrees C>: override all critical trip points
  1799. thermal.nocrt= [HW,ACPI]
  1800. Set to disable actions on ACPI thermal zone
  1801. critical and hot trip points.
  1802. thermal.off= [HW,ACPI]
  1803. 1: disable ACPI thermal control
  1804. thermal.psv= [HW,ACPI]
  1805. -1: disable all passive trip points
  1806. <degrees C>: override all passive trip points to this
  1807. value
  1808. thermal.tzp= [HW,ACPI]
  1809. Specify global default ACPI thermal zone polling rate
  1810. <deci-seconds>: poll all this frequency
  1811. 0: no polling (default)
  1812. tmscsim= [HW,SCSI]
  1813. See comment before function dc390_setup() in
  1814. drivers/scsi/tmscsim.c.
  1815. topology= [S390]
  1816. Format: {off | on}
  1817. Specify if the kernel should make use of the cpu
  1818. topology informations if the hardware supports these.
  1819. The scheduler will make use of these informations and
  1820. e.g. base its process migration decisions on it.
  1821. Default is off.
  1822. tp720= [HW,PS2]
  1823. trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
  1824. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1825. Format:
  1826. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1827. tsc= Disable clocksource-must-verify flag for TSC.
  1828. Format: <string>
  1829. [x86] reliable: mark tsc clocksource as reliable, this
  1830. disables clocksource verification at runtime.
  1831. Used to enable high-resolution timer mode on older
  1832. hardware, and in virtualized environment.
  1833. turbografx.map[2|3]= [HW,JOY]
  1834. TurboGraFX parallel port interface
  1835. Format:
  1836. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1837. See also Documentation/input/joystick-parport.txt
  1838. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1839. See header of drivers/scsi/u14-34f.c.
  1840. uart401= [HW,OSS]
  1841. Format: <io>,<irq>
  1842. uart6850= [HW,OSS]
  1843. Format: <io>,<irq>
  1844. uhci-hcd.ignore_oc=
  1845. [USB] Ignore overcurrent events (default N).
  1846. Some badly-designed motherboards generate lots of
  1847. bogus events, for ports that aren't wired to
  1848. anything. Set this parameter to avoid log spamming.
  1849. Note that genuine overcurrent events won't be
  1850. reported either.
  1851. unknown_nmi_panic
  1852. [X86-32,X86-64]
  1853. Set unknown_nmi_panic=1 early on boot.
  1854. usbcore.autosuspend=
  1855. [USB] The autosuspend time delay (in seconds) used
  1856. for newly-detected USB devices (default 2). This
  1857. is the time required before an idle device will be
  1858. autosuspended. Devices for which the delay is set
  1859. to a negative value won't be autosuspended at all.
  1860. usbcore.usbfs_snoop=
  1861. [USB] Set to log all usbfs traffic (default 0 = off).
  1862. usbcore.blinkenlights=
  1863. [USB] Set to cycle leds on hubs (default 0 = off).
  1864. usbcore.old_scheme_first=
  1865. [USB] Start with the old device initialization
  1866. scheme (default 0 = off).
  1867. usbcore.use_both_schemes=
  1868. [USB] Try the other device initialization scheme
  1869. if the first one fails (default 1 = enabled).
  1870. usbcore.initial_descriptor_timeout=
  1871. [USB] Specifies timeout for the initial 64-byte
  1872. USB_REQ_GET_DESCRIPTOR request in milliseconds
  1873. (default 5000 = 5.0 seconds).
  1874. usbhid.mousepoll=
  1875. [USBHID] The interval which mice are to be polled at.
  1876. usb-storage.delay_use=
  1877. [UMS] The delay in seconds before a new device is
  1878. scanned for Logical Units (default 5).
  1879. usb-storage.quirks=
  1880. [UMS] A list of quirks entries to supplement or
  1881. override the built-in unusual_devs list. List
  1882. entries are separated by commas. Each entry has
  1883. the form VID:PID:Flags where VID and PID are Vendor
  1884. and Product ID values (4-digit hex numbers) and
  1885. Flags is a set of characters, each corresponding
  1886. to a common usb-storage quirk flag as follows:
  1887. a = SANE_SENSE (collect more than 18 bytes
  1888. of sense data);
  1889. c = FIX_CAPACITY (decrease the reported
  1890. device capacity by one sector);
  1891. h = CAPACITY_HEURISTICS (decrease the
  1892. reported device capacity by one
  1893. sector if the number is odd);
  1894. i = IGNORE_DEVICE (don't bind to this
  1895. device);
  1896. l = NOT_LOCKABLE (don't try to lock and
  1897. unlock ejectable media);
  1898. m = MAX_SECTORS_64 (don't transfer more
  1899. than 64 sectors = 32 KB at a time);
  1900. o = CAPACITY_OK (accept the capacity
  1901. reported by the device);
  1902. r = IGNORE_RESIDUE (the device reports
  1903. bogus residue values);
  1904. s = SINGLE_LUN (the device has only one
  1905. Logical Unit);
  1906. w = NO_WP_DETECT (don't test whether the
  1907. medium is write-protected).
  1908. Example: quirks=0419:aaf5:rl,0421:0433:rc
  1909. vdso= [X86-32,SH,x86-64]
  1910. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1911. vdso=1: enable VDSO (default)
  1912. vdso=0: disable VDSO mapping
  1913. vdso32= [X86-32,X86-64]
  1914. vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
  1915. vdso32=1: enable 32-bit VDSO (default)
  1916. vdso32=0: disable 32-bit VDSO mapping
  1917. vector= [IA-64,SMP]
  1918. vector=percpu: enable percpu vector domain
  1919. video= [FB] Frame buffer configuration
  1920. See Documentation/fb/modedb.txt.
  1921. vga= [BOOT,X86-32] Select a particular video mode
  1922. See Documentation/x86/boot.txt and
  1923. Documentation/svga.txt.
  1924. Use vga=ask for menu.
  1925. This is actually a boot loader parameter; the value is
  1926. passed to the kernel using a special protocol.
  1927. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1928. size of <nn>. This can be used to increase the
  1929. minimum size (128MB on x86). It can also be used to
  1930. decrease the size and leave more room for directly
  1931. mapped kernel RAM.
  1932. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1933. Format: <command>
  1934. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1935. Format: <command>
  1936. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1937. Format: <command>
  1938. vt.default_blu= [VT]
  1939. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  1940. Change the default blue palette of the console.
  1941. This is a 16-member array composed of values
  1942. ranging from 0-255.
  1943. vt.default_grn= [VT]
  1944. Format: <green0>,<green1>,<green2>,...,<green15>
  1945. Change the default green palette of the console.
  1946. This is a 16-member array composed of values
  1947. ranging from 0-255.
  1948. vt.default_red= [VT]
  1949. Format: <red0>,<red1>,<red2>,...,<red15>
  1950. Change the default red palette of the console.
  1951. This is a 16-member array composed of values
  1952. ranging from 0-255.
  1953. vt.default_utf8=
  1954. [VT]
  1955. Format=<0|1>
  1956. Set system-wide default UTF-8 mode for all tty's.
  1957. Default is 1, i.e. UTF-8 mode is enabled for all
  1958. newly opened terminals.
  1959. waveartist= [HW,OSS]
  1960. Format: <io>,<irq>,<dma>,<dma2>
  1961. wd33c93= [HW,SCSI]
  1962. See header of drivers/scsi/wd33c93.c.
  1963. wd7000= [HW,SCSI]
  1964. See header of drivers/scsi/wd7000.c.
  1965. wdt= [WDT] Watchdog
  1966. See Documentation/watchdog/wdt.txt.
  1967. x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
  1968. default x2apic cluster mode on platforms
  1969. supporting x2apic.
  1970. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1971. xd_geo= See header of drivers/block/xd.c.
  1972. xirc2ps_cs= [NET,PCMCIA]
  1973. Format:
  1974. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1975. ______________________________________________________________________
  1976. TODO:
  1977. Add documentation for ALSA options.
  1978. Add more DRM drivers.