kernel-parameters.txt 61 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239124012411242124312441245124612471248124912501251125212531254125512561257125812591260126112621263126412651266126712681269127012711272127312741275127612771278127912801281128212831284128512861287128812891290129112921293129412951296129712981299130013011302130313041305130613071308130913101311131213131314131513161317131813191320132113221323132413251326132713281329133013311332133313341335133613371338133913401341134213431344134513461347134813491350135113521353135413551356135713581359136013611362136313641365136613671368136913701371137213731374137513761377137813791380138113821383138413851386138713881389139013911392139313941395139613971398139914001401140214031404140514061407140814091410141114121413141414151416141714181419142014211422142314241425142614271428142914301431143214331434143514361437143814391440144114421443144414451446144714481449145014511452145314541455145614571458145914601461146214631464146514661467146814691470147114721473147414751476147714781479148014811482148314841485148614871488148914901491149214931494149514961497149814991500150115021503150415051506150715081509151015111512151315141515151615171518151915201521152215231524152515261527152815291530153115321533153415351536153715381539154015411542154315441545154615471548154915501551155215531554155515561557155815591560156115621563156415651566156715681569157015711572157315741575157615771578157915801581158215831584158515861587158815891590159115921593159415951596159715981599160016011602160316041605160616071608160916101611161216131614161516161617161816191620162116221623162416251626162716281629163016311632163316341635163616371638163916401641164216431644164516461647164816491650165116521653165416551656165716581659166016611662166316641665166616671668166916701671167216731674167516761677167816791680168116821683168416851686168716881689169016911692169316941695169616971698169917001701170217031704170517061707170817091710171117121713171417151716171717181719172017211722172317241725172617271728172917301731173217331734173517361737173817391740174117421743174417451746174717481749175017511752175317541755175617571758175917601761176217631764176517661767176817691770177117721773177417751776177717781779178017811782178317841785178617871788178917901791179217931794179517961797179817991800180118021803180418051806180718081809181018111812181318141815181618171818181918201821182218231824182518261827182818291830183118321833183418351836183718381839184018411842184318441845184618471848184918501851185218531854185518561857185818591860186118621863186418651866186718681869187018711872187318741875187618771878187918801881188218831884188518861887188818891890189118921893189418951896189718981899190019011902190319041905190619071908190919101911191219131914191519161917191819191920192119221923192419251926192719281929193019311932193319341935193619371938193919401941194219431944194519461947194819491950195119521953195419551956195719581959196019611962196319641965196619671968196919701971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995
  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. AX25 Appropriate AX.25 support is enabled.
  30. BLACKFIN Blackfin architecture is enabled.
  31. DRM Direct Rendering Management support is enabled.
  32. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  33. EFI EFI Partitioning (GPT) is enabled
  34. EIDE EIDE/ATAPI support is enabled.
  35. FB The frame buffer device is enabled.
  36. HW Appropriate hardware is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LIBATA Libata driver is enabled
  44. LP Printer support is enabled.
  45. LOOP Loopback device support is enabled.
  46. M68k M68k architecture is enabled.
  47. These options have more detailed description inside of
  48. Documentation/m68k/kernel-options.txt.
  49. MCA MCA bus support is enabled.
  50. MDA MDA console support is enabled.
  51. MOUSE Appropriate mouse support is enabled.
  52. MSI Message Signaled Interrupts (PCI).
  53. MTD MTD (Memory Technology Device) support is enabled.
  54. NET Appropriate network support is enabled.
  55. NUMA NUMA support is enabled.
  56. GENERIC_TIME The generic timeofday code is enabled.
  57. NFS Appropriate NFS support is enabled.
  58. OSS OSS sound support is enabled.
  59. PV_OPS A paravirtualized kernel is enabled.
  60. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  61. PARISC The PA-RISC architecture is enabled.
  62. PCI PCI bus support is enabled.
  63. PCIE PCI Express support is enabled.
  64. PCMCIA The PCMCIA subsystem is enabled.
  65. PNP Plug & Play support is enabled.
  66. PPC PowerPC architecture is enabled.
  67. PPT Parallel port support is enabled.
  68. PS2 Appropriate PS/2 support is enabled.
  69. RAM RAM disk support is enabled.
  70. ROOTPLUG The example Root Plug LSM is enabled.
  71. S390 S390 architecture is enabled.
  72. SCSI Appropriate SCSI support is enabled.
  73. A lot of drivers has their options described inside of
  74. Documentation/scsi/.
  75. SECURITY Different security models are enabled.
  76. SELINUX SELinux support is enabled.
  77. SERIAL Serial support is enabled.
  78. SH SuperH architecture is enabled.
  79. SMP The kernel is an SMP kernel.
  80. SPARC Sparc architecture is enabled.
  81. SWSUSP Software suspend is enabled.
  82. TS Appropriate touchscreen support is enabled.
  83. USB USB support is enabled.
  84. USBHID USB Human Interface Device support is enabled.
  85. V4L Video For Linux support is enabled.
  86. VGA The VGA console has been enabled.
  87. VT Virtual terminal support is enabled.
  88. WDT Watchdog support is enabled.
  89. XT IBM PC/XT MFM hard disk support is enabled.
  90. X86-32 X86-32, aka i386 architecture is enabled.
  91. X86-64 X86-64 architecture is enabled.
  92. More X86-64 boot options can be found in
  93. Documentation/x86_64/boot-options.txt .
  94. In addition, the following text indicates that the option:
  95. BUGS= Relates to possible processor bugs on the said processor.
  96. KNL Is a kernel start-up parameter.
  97. BOOT Is a boot loader parameter.
  98. Parameters denoted with BOOT are actually interpreted by the boot
  99. loader, and have no meaning to the kernel directly.
  100. Do not modify the syntax of boot loader parameters without extreme
  101. need or coordination with <Documentation/i386/boot.txt>.
  102. There are also arch-specific kernel-parameters not documented here.
  103. See for example <Documentation/x86_64/boot-options.txt>.
  104. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  105. a trailing = on the name of any parameter states that that parameter will
  106. be entered as an environment variable, whereas its absence indicates that
  107. it will appear as a kernel argument readable via /proc/cmdline by programs
  108. running once the system is up.
  109. The number of kernel parameters is not limited, but the length of the
  110. complete command line (parameters including spaces etc.) is limited to
  111. a fixed number of characters. This limit depends on the architecture
  112. and is between 256 and 4096 characters. It is defined in the file
  113. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  114. acpi= [HW,ACPI,X86-64,i386]
  115. Advanced Configuration and Power Interface
  116. Format: { force | off | ht | strict | noirq }
  117. force -- enable ACPI if default was off
  118. off -- disable ACPI if default was on
  119. noirq -- do not use ACPI for IRQ routing
  120. ht -- run only enough ACPI to enable Hyper Threading
  121. strict -- Be less tolerant of platforms that are not
  122. strictly ACPI specification compliant.
  123. See also Documentation/pm.txt, pci=noacpi
  124. acpi_apic_instance= [ACPI, IOAPIC]
  125. Format: <int>
  126. 2: use 2nd APIC table, if available
  127. 1,0: use 1st APIC table
  128. default: 0
  129. acpi_sleep= [HW,ACPI] Sleep options
  130. Format: { s3_bios, s3_mode }
  131. See Documentation/power/video.txt
  132. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  133. Format: { level | edge | high | low }
  134. acpi_irq_balance [HW,ACPI]
  135. ACPI will balance active IRQs
  136. default in APIC mode
  137. acpi_irq_nobalance [HW,ACPI]
  138. ACPI will not move active IRQs (default)
  139. default in PIC mode
  140. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  141. use by PCI
  142. Format: <irq>,<irq>...
  143. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  144. Format: <irq>,<irq>...
  145. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  146. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  147. Format: To spoof as Windows 98: ="Microsoft Windows"
  148. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  149. acpi_osi="string1" # add string1 -- only one string
  150. acpi_osi="!string2" # remove built-in string2
  151. acpi_osi= # disable all strings
  152. acpi_serialize [HW,ACPI] force serialization of AML methods
  153. acpi_skip_timer_override [HW,ACPI]
  154. Recognize and ignore IRQ0/pin2 Interrupt Override.
  155. For broken nForce2 BIOS resulting in XT-PIC timer.
  156. acpi_use_timer_override [HW,ACPI}
  157. Use timer override. For some broken Nvidia NF5 boards
  158. that require a timer override, but don't have
  159. HPET
  160. acpi.debug_layer= [HW,ACPI]
  161. Format: <int>
  162. Each bit of the <int> indicates an ACPI debug layer,
  163. 1: enable, 0: disable. It is useful for boot time
  164. debugging. After system has booted up, it can be set
  165. via /sys/module/acpi/parameters/debug_layer.
  166. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  167. Available bits (add the numbers together) to enable debug output
  168. for specific parts of the ACPI subsystem:
  169. 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
  170. 0x10 namespace 0x20 parser 0x40 dispatcher
  171. 0x80 executer 0x100 resources 0x200 acpica debugger
  172. 0x400 os services 0x800 acpica disassembler.
  173. The number can be in decimal or prefixed with 0x in hex.
  174. Warning: Many of these options can produce a lot of
  175. output and make your system unusable. Be very careful.
  176. acpi.debug_level= [HW,ACPI]
  177. Format: <int>
  178. Each bit of the <int> indicates an ACPI debug level,
  179. 1: enable, 0: disable. It is useful for boot time
  180. debugging. After system has booted up, it can be set
  181. via /sys/module/acpi/parameters/debug_level.
  182. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  183. Available bits (add the numbers together) to enable different
  184. debug output levels of the ACPI subsystem:
  185. 0x01 error 0x02 warn 0x04 init 0x08 debug object
  186. 0x10 info 0x20 init names 0x40 parse 0x80 load
  187. 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
  188. 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
  189. 0x10000 resources 0x20000 user requests 0x40000 package.
  190. The number can be in decimal or prefixed with 0x in hex.
  191. Warning: Many of these options can produce a lot of
  192. output and make your system unusable. Be very careful.
  193. acpi_pm_good [X86-32,X86-64]
  194. Override the pmtimer bug detection: force the kernel
  195. to assume that this machine's pmtimer latches its value
  196. and always returns good values.
  197. agp= [AGP]
  198. { off | try_unsupported }
  199. off: disable AGP support
  200. try_unsupported: try to drive unsupported chipsets
  201. (may crash computer or cause data corruption)
  202. enable_timer_pin_1 [i386,x86-64]
  203. Enable PIN 1 of APIC timer
  204. Can be useful to work around chipset bugs
  205. (in particular on some ATI chipsets).
  206. The kernel tries to set a reasonable default.
  207. disable_timer_pin_1 [i386,x86-64]
  208. Disable PIN 1 of APIC timer
  209. Can be useful to work around chipset bugs.
  210. ad1848= [HW,OSS]
  211. Format: <io>,<irq>,<dma>,<dma2>,<type>
  212. advansys= [HW,SCSI]
  213. See header of drivers/scsi/advansys.c.
  214. advwdt= [HW,WDT] Advantech WDT
  215. Format: <iostart>,<iostop>
  216. aedsp16= [HW,OSS] Audio Excel DSP 16
  217. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  218. See also header of sound/oss/aedsp16.c.
  219. aha152x= [HW,SCSI]
  220. See Documentation/scsi/aha152x.txt.
  221. aha1542= [HW,SCSI]
  222. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  223. aic7xxx= [HW,SCSI]
  224. See Documentation/scsi/aic7xxx.txt.
  225. aic79xx= [HW,SCSI]
  226. See Documentation/scsi/aic79xx.txt.
  227. amijoy.map= [HW,JOY] Amiga joystick support
  228. Map of devices attached to JOY0DAT and JOY1DAT
  229. Format: <a>,<b>
  230. See also Documentation/kernel/input/joystick.txt
  231. analog.map= [HW,JOY] Analog joystick and gamepad support
  232. Specifies type or capabilities of an analog joystick
  233. connected to one of 16 gameports
  234. Format: <type1>,<type2>,..<type16>
  235. apc= [HW,SPARC]
  236. Power management functions (SPARCstation-4/5 + deriv.)
  237. Format: noidle
  238. Disable APC CPU standby support. SPARCstation-Fox does
  239. not play well with APC CPU idle - disable it if you have
  240. APC and your system crashes randomly.
  241. apic= [APIC,i386] Advanced Programmable Interrupt Controller
  242. Change the output verbosity whilst booting
  243. Format: { quiet (default) | verbose | debug }
  244. Change the amount of debugging information output
  245. when initialising the APIC and IO-APIC components.
  246. apm= [APM] Advanced Power Management
  247. See header of arch/i386/kernel/apm.c.
  248. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  249. Format: <io>,<irq>,<nodeID>
  250. ataflop= [HW,M68k]
  251. atarimouse= [HW,MOUSE] Atari Mouse
  252. atascsi= [HW,SCSI] Atari SCSI
  253. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  254. EzKey and similar keyboards
  255. atkbd.reset= [HW] Reset keyboard during initialization
  256. atkbd.set= [HW] Select keyboard code set
  257. Format: <int> (2 = AT (default), 3 = PS/2)
  258. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  259. keyboards
  260. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  261. Format: <bool> (0 = real, 1 = synthetic (default))
  262. atkbd.softrepeat= [HW]
  263. Use software keyboard repeat
  264. autotest [IA64]
  265. baycom_epp= [HW,AX25]
  266. Format: <io>,<mode>
  267. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  268. Format: <io>,<mode>
  269. See header of drivers/net/hamradio/baycom_par.c.
  270. baycom_ser_fdx= [HW,AX25]
  271. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  272. Format: <io>,<irq>,<mode>[,<baud>]
  273. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  274. baycom_ser_hdx= [HW,AX25]
  275. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  276. Format: <io>,<irq>,<mode>
  277. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  278. boot_delay= Milliseconds to delay each printk during boot.
  279. Values larger than 10 seconds (10000) are changed to
  280. no delay (0).
  281. Format: integer
  282. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  283. bttv.radio= Most important insmod options are available as
  284. kernel args too.
  285. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  286. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  287. BusLogic= [HW,SCSI]
  288. See drivers/scsi/BusLogic.c, comment before function
  289. BusLogic_ParseDriverOptions().
  290. c101= [NET] Moxa C101 synchronous serial card
  291. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  292. Sometimes CPU hardware bugs make them report the cache
  293. size incorrectly. The kernel will attempt work arounds
  294. to fix known problems, but for some CPUs it is not
  295. possible to determine what the correct size should be.
  296. This option provides an override for these situations.
  297. capability.disable=
  298. [SECURITY] Disable capabilities. This would normally
  299. be used only if an alternative security model is to be
  300. configured. Potentially dangerous and should only be
  301. used if you are entirely sure of the consequences.
  302. chandev= [HW,NET] Generic channel device initialisation
  303. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  304. Format: { "0" | "1" }
  305. See security/selinux/Kconfig help text.
  306. 0 -- check protection applied by kernel (includes
  307. any implied execute protection).
  308. 1 -- check protection requested by application.
  309. Default value is set via a kernel config option.
  310. Value can be changed at runtime via
  311. /selinux/checkreqprot.
  312. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  313. [Deprecated]
  314. Forces specified clocksource (if available) to be used
  315. when calculating gettimeofday(). If specified
  316. clocksource is not available, it defaults to PIT.
  317. Format: { pit | tsc | cyclone | pmtmr }
  318. clocksource= [GENERIC_TIME] Override the default clocksource
  319. Format: <string>
  320. Override the default clocksource and use the clocksource
  321. with the name specified.
  322. Some clocksource names to choose from, depending on
  323. the platform:
  324. [all] jiffies (this is the base, fallback clocksource)
  325. [ACPI] acpi_pm
  326. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  327. pxa_timer,timer3,32k_counter,timer0_1
  328. [AVR32] avr32
  329. [X86-32] pit,hpet,tsc,vmi-timer;
  330. scx200_hrt on Geode; cyclone on IBM x440
  331. [MIPS] MIPS
  332. [PARISC] cr16
  333. [S390] tod
  334. [SH] SuperH
  335. [SPARC64] tick
  336. [X86-64] hpet,tsc
  337. code_bytes [IA32] How many bytes of object code to print in an
  338. oops report.
  339. Range: 0 - 8192
  340. Default: 64
  341. disable_8254_timer
  342. enable_8254_timer
  343. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  344. over the 8254 in addition to over the IO-APIC. The
  345. kernel tries to set a sensible default.
  346. hpet= [X86-32,HPET] option to control HPET usage
  347. Format: { enable (default) | disable | force }
  348. disable: disable HPET and use PIT instead
  349. force: allow force enabled of undocumented chips (ICH4, VIA)
  350. com20020= [HW,NET] ARCnet - COM20020 chipset
  351. Format:
  352. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  353. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  354. Format: <io>[,<irq>]
  355. com90xx= [HW,NET]
  356. ARCnet - COM90xx chipset (memory-mapped buffers)
  357. Format: <io>[,<irq>[,<memstart>]]
  358. condev= [HW,S390] console device
  359. conmode=
  360. console= [KNL] Output console device and options.
  361. tty<n> Use the virtual console device <n>.
  362. ttyS<n>[,options]
  363. ttyUSB0[,options]
  364. Use the specified serial port. The options are of
  365. the form "bbbbpnf", where "bbbb" is the baud rate,
  366. "p" is parity ("n", "o", or "e"), "n" is number of
  367. bits, and "f" is flow control ("r" for RTS or
  368. omit it). Default is "9600n8".
  369. See Documentation/serial-console.txt for more
  370. information. See
  371. Documentation/networking/netconsole.txt for an
  372. alternative.
  373. uart[8250],io,<addr>[,options]
  374. uart[8250],mmio,<addr>[,options]
  375. Start an early, polled-mode console on the 8250/16550
  376. UART at the specified I/O port or MMIO address,
  377. switching to the matching ttyS device later. The
  378. options are the same as for ttyS, above.
  379. earlycon= [KNL] Output early console device and options.
  380. uart[8250],io,<addr>[,options]
  381. uart[8250],mmio,<addr>[,options]
  382. Start an early, polled-mode console on the 8250/16550
  383. UART at the specified I/O port or MMIO address.
  384. The options are the same as for ttyS, above.
  385. no_console_suspend
  386. [HW] Never suspend the console
  387. Disable suspending of consoles during suspend and
  388. hibernate operations. Once disabled, debugging
  389. messages can reach various consoles while the rest
  390. of the system is being put to sleep (ie, while
  391. debugging driver suspend/resume hooks). This may
  392. not work reliably with all consoles, but is known
  393. to work with serial and VGA consoles.
  394. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  395. Format:
  396. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  397. crashkernel=nn[KMG]@ss[KMG]
  398. [KNL] Reserve a chunk of physical memory to
  399. hold a kernel to switch to with kexec on panic.
  400. crashkernel=range1:size1[,range2:size2,...][@offset]
  401. [KNL] Same as above, but depends on the memory
  402. in the running system. The syntax of range is
  403. start-[end] where start and end are both
  404. a memory unit (amount[KMG]). See also
  405. Documentation/kdump/kdump.txt for a example.
  406. cs4232= [HW,OSS]
  407. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  408. cs89x0_dma= [HW,NET]
  409. Format: <dma>
  410. cs89x0_media= [HW,NET]
  411. Format: { rj45 | aui | bnc }
  412. dasd= [HW,NET]
  413. See header of drivers/s390/block/dasd_devmap.c.
  414. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  415. (one device per port)
  416. Format: <port#>,<type>
  417. See also Documentation/input/joystick-parport.txt
  418. debug [KNL] Enable kernel debugging (events log level).
  419. debug_locks_verbose=
  420. [KNL] verbose self-tests
  421. Format=<0|1>
  422. Print debugging info while doing the locking API
  423. self-tests.
  424. We default to 0 (no extra messages), setting it to
  425. 1 will print _a lot_ more information - normally
  426. only useful to kernel developers.
  427. decnet= [HW,NET]
  428. Format: <area>[,<node>]
  429. See also Documentation/networking/decnet.txt.
  430. default_blu= [VT]
  431. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  432. Change the default blue palette of the console.
  433. This is a 16-member array composed of values
  434. ranging from 0-255.
  435. default_grn= [VT]
  436. Format: <green0>,<green1>,<green2>,...,<green15>
  437. Change the default green palette of the console.
  438. This is a 16-member array composed of values
  439. ranging from 0-255.
  440. default_red= [VT]
  441. Format: <red0>,<red1>,<red2>,...,<red15>
  442. Change the default red palette of the console.
  443. This is a 16-member array composed of values
  444. ranging from 0-255.
  445. default_utf8= [VT]
  446. Format=<0|1>
  447. Set system-wide default UTF-8 mode for all tty's.
  448. Default is 0 and by setting to 1, it enables UTF-8
  449. mode for all newly opened or allocated terminals.
  450. dhash_entries= [KNL]
  451. Set number of hash buckets for dentry cache.
  452. digi= [HW,SERIAL]
  453. IO parameters + enable/disable command.
  454. digiepca= [HW,SERIAL]
  455. See drivers/char/README.epca and
  456. Documentation/digiepca.txt.
  457. dmasound= [HW,OSS] Sound subsystem buffers
  458. dscc4.setup= [NET]
  459. dtc3181e= [HW,SCSI]
  460. earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
  461. earlyprintk=vga
  462. earlyprintk=serial[,ttySn[,baudrate]]
  463. Append ",keep" to not disable it when the real console
  464. takes over.
  465. Only vga or serial at a time, not both.
  466. Currently only ttyS0 and ttyS1 are supported.
  467. Interaction with the standard serial driver is not
  468. very good.
  469. The VGA output is eventually overwritten by the real
  470. console.
  471. eata= [HW,SCSI]
  472. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  473. Format: <int>
  474. 0: polling mode
  475. non-0: interrupt mode (default)
  476. edd= [EDD]
  477. Format: {"of[f]" | "sk[ipmbr]"}
  478. See comment in arch/i386/boot/edd.S
  479. eisa_irq_edge= [PARISC,HW]
  480. See header of drivers/parisc/eisa.c.
  481. elanfreq= [X86-32]
  482. See comment before function elanfreq_setup() in
  483. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  484. elevator= [IOSCHED]
  485. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  486. See Documentation/block/as-iosched.txt and
  487. Documentation/block/deadline-iosched.txt for details.
  488. elfcorehdr= [X86-32, X86_64]
  489. Specifies physical address of start of kernel core
  490. image elf header. Generally kexec loader will
  491. pass this option to capture kernel.
  492. See Documentation/kdump/kdump.txt for details.
  493. enforcing [SELINUX] Set initial enforcing status.
  494. Format: {"0" | "1"}
  495. See security/selinux/Kconfig help text.
  496. 0 -- permissive (log only, no denials).
  497. 1 -- enforcing (deny and log).
  498. Default value is 0.
  499. Value can be changed at runtime via /selinux/enforce.
  500. es1371= [HW,OSS]
  501. Format: <spdif>,[<nomix>,[<amplifier>]]
  502. See also header of sound/oss/es1371.c.
  503. ether= [HW,NET] Ethernet cards parameters
  504. This option is obsoleted by the "netdev=" option, which
  505. has equivalent usage. See its documentation for details.
  506. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  507. Format: <io>[,<irq>]
  508. failslab=
  509. fail_page_alloc=
  510. fail_make_request=[KNL]
  511. General fault injection mechanism.
  512. Format: <interval>,<probability>,<space>,<times>
  513. See also /Documentation/fault-injection/.
  514. fd_mcs= [HW,SCSI]
  515. See header of drivers/scsi/fd_mcs.c.
  516. fdomain= [HW,SCSI]
  517. See header of drivers/scsi/fdomain.c.
  518. floppy= [HW]
  519. See Documentation/floppy.txt.
  520. gamecon.map[2|3]=
  521. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  522. support via parallel port (up to 5 devices per port)
  523. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  524. See also Documentation/input/joystick-parport.txt
  525. gamma= [HW,DRM]
  526. gdth= [HW,SCSI]
  527. See header of drivers/scsi/gdth.c.
  528. gpt [EFI] Forces disk with valid GPT signature but
  529. invalid Protective MBR to be treated as GPT.
  530. gvp11= [HW,SCSI]
  531. hashdist= [KNL,NUMA] Large hashes allocated during boot
  532. are distributed across NUMA nodes. Defaults on
  533. for IA-64, off otherwise.
  534. Format: 0 | 1 (for off | on)
  535. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  536. hd= [EIDE] (E)IDE hard drive subsystem geometry
  537. Format: <cyl>,<head>,<sect>
  538. hd?= [HW] (E)IDE subsystem
  539. hd?lun= See Documentation/ide.txt.
  540. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  541. size of <nn>. This works even on boxes that have no
  542. highmem otherwise. This also works to reduce highmem
  543. size on bigger boxes.
  544. highres= [KNL] Enable/disable high resolution timer mode.
  545. Valid parameters: "on", "off"
  546. Default: "on"
  547. hisax= [HW,ISDN]
  548. See Documentation/isdn/README.HiSax.
  549. hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
  550. i8042.direct [HW] Put keyboard port into non-translated mode
  551. i8042.dumbkbd [HW] Pretend that controller can only read data from
  552. keyboard and cannot control its state
  553. (Don't attempt to blink the leds)
  554. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  555. i8042.nokbd [HW] Don't check/create keyboard port
  556. i8042.nomux [HW] Don't check presence of an active multiplexing
  557. controller
  558. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  559. controllers
  560. i8042.panicblink=
  561. [HW] Frequency with which keyboard LEDs should blink
  562. when kernel panics (default is 0.5 sec)
  563. i8042.reset [HW] Reset the controller during init and cleanup
  564. i8042.unlock [HW] Unlock (ignore) the keylock
  565. i810= [HW,DRM]
  566. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  567. indicates that the driver is running on unsupported
  568. hardware.
  569. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  570. does not match list of supported models.
  571. i8k.power_status
  572. [HW] Report power status in /proc/i8k
  573. (disabled by default)
  574. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  575. capability is set.
  576. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  577. See Documentation/mca.txt.
  578. icn= [HW,ISDN]
  579. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  580. ide= [HW] (E)IDE subsystem
  581. Format: ide=nodma or ide=doubler or ide=reverse
  582. See Documentation/ide.txt.
  583. ide?= [HW] (E)IDE subsystem
  584. Format: ide?=noprobe or chipset specific parameters.
  585. See Documentation/ide.txt.
  586. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  587. See Documentation/ide.txt.
  588. idle= [X86]
  589. Format: idle=poll or idle=mwait
  590. Poll forces a polling idle loop that can slightly improves the performance
  591. of waking up a idle CPU, but will use a lot of power and make the system
  592. run hot. Not recommended.
  593. idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
  594. to not use it because it doesn't save as much power as a normal idle
  595. loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
  596. as idle=poll.
  597. ignore_loglevel [KNL]
  598. Ignore loglevel setting - this will print /all/
  599. kernel messages to the console. Useful for debugging.
  600. ihash_entries= [KNL]
  601. Set number of hash buckets for inode cache.
  602. in2000= [HW,SCSI]
  603. See header of drivers/scsi/in2000.c.
  604. init= [KNL]
  605. Format: <full_path>
  606. Run specified binary instead of /sbin/init as init
  607. process.
  608. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  609. for working out where the kernel is dying during
  610. startup.
  611. initrd= [BOOT] Specify the location of the initial ramdisk
  612. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  613. Format: <irq>
  614. inttest= [IA64]
  615. io7= [HW] IO7 for Marvel based alpha systems
  616. See comment before marvel_specify_io7 in
  617. arch/alpha/kernel/core_marvel.c.
  618. ip= [IP_PNP]
  619. See Documentation/nfsroot.txt.
  620. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  621. See comment before ip2_setup() in
  622. drivers/char/ip2/ip2base.c.
  623. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  624. See header of drivers/scsi/ips.c.
  625. ports= [IP_VS_FTP] IPVS ftp helper module
  626. Default is 21.
  627. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  628. may be specified.
  629. Format: <port>,<port>....
  630. irqfixup [HW]
  631. When an interrupt is not handled search all handlers
  632. for it. Intended to get systems with badly broken
  633. firmware running.
  634. irqpoll [HW]
  635. When an interrupt is not handled search all handlers
  636. for it. Also check all handlers each timer
  637. interrupt. Intended to get systems with badly broken
  638. firmware running.
  639. isapnp= [ISAPNP]
  640. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  641. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  642. Format:
  643. <cpu number>,...,<cpu number>
  644. or
  645. <cpu number>-<cpu number> (must be a positive range in ascending order)
  646. or a mixture
  647. <cpu number>,...,<cpu number>-<cpu number>
  648. This option can be used to specify one or more CPUs
  649. to isolate from the general SMP balancing and scheduling
  650. algorithms. The only way to move a process onto or off
  651. an "isolated" CPU is via the CPU affinity syscalls.
  652. <cpu number> begins at 0 and the maximum value is
  653. "number of CPUs in system - 1".
  654. This option is the preferred way to isolate CPUs. The
  655. alternative -- manually setting the CPU mask of all
  656. tasks in the system -- can cause problems and
  657. suboptimal load balancer performance.
  658. iucv= [HW,NET]
  659. js= [HW,JOY] Analog joystick
  660. See Documentation/input/joystick.txt.
  661. kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  662. specifies the amount of memory usable by the kernel
  663. for non-movable allocations. The requested amount is
  664. spread evenly throughout all nodes in the system. The
  665. remaining memory in each node is used for Movable
  666. pages. In the event, a node is too small to have both
  667. kernelcore and Movable pages, kernelcore pages will
  668. take priority and other nodes will have a larger number
  669. of kernelcore pages. The Movable zone is used for the
  670. allocation of pages that may be reclaimed or moved
  671. by the page migration subsystem. This means that
  672. HugeTLB pages may not be allocated from this zone.
  673. Note that allocations like PTEs-from-HighMem still
  674. use the HighMem zone if it exists, and the Normal
  675. zone if it does not.
  676. movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  677. is similar to kernelcore except it specifies the
  678. amount of memory used for migratable allocations.
  679. If both kernelcore and movablecore is specified,
  680. then kernelcore will be at *least* the specified
  681. value but may be more. If movablecore on its own
  682. is specified, the administrator must be careful
  683. that the amount of memory usable for all allocations
  684. is not too small.
  685. keepinitrd [HW,ARM]
  686. kstack=N [X86-32,X86-64] Print N words from the kernel stack
  687. in oops dumps.
  688. l2cr= [PPC]
  689. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  690. disabled it.
  691. lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
  692. C2 power state.
  693. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  694. when set.
  695. Format: <int>
  696. load_ramdisk= [RAM] List of ramdisks to load from floppy
  697. See Documentation/ramdisk.txt.
  698. lockd.nlm_grace_period=P [NFS] Assign grace period.
  699. Format: <integer>
  700. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  701. Format: <integer>
  702. lockd.nlm_timeout=T [NFS] Assign timeout value.
  703. Format: <integer>
  704. lockd.nlm_udpport=M [NFS] Assign UDP port.
  705. Format: <integer>
  706. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  707. Format: <irq>
  708. loglevel= All Kernel Messages with a loglevel smaller than the
  709. console loglevel will be printed to the console. It can
  710. also be changed with klogd or other programs. The
  711. loglevels are defined as follows:
  712. 0 (KERN_EMERG) system is unusable
  713. 1 (KERN_ALERT) action must be taken immediately
  714. 2 (KERN_CRIT) critical conditions
  715. 3 (KERN_ERR) error conditions
  716. 4 (KERN_WARNING) warning conditions
  717. 5 (KERN_NOTICE) normal but significant condition
  718. 6 (KERN_INFO) informational
  719. 7 (KERN_DEBUG) debug-level messages
  720. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  721. Format: { n | nk | nM }
  722. n must be a power of two. The default size
  723. is set in the kernel config file.
  724. logo.nologo [FB] Disables display of the built-in Linux logo.
  725. This may be used to provide more screen space for
  726. kernel log messages and is useful when debugging
  727. kernel boot problems.
  728. lp=0 [LP] Specify parallel ports to use, e.g,
  729. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  730. lp=reset first parallel port). 'lp=0' disables the
  731. lp=auto printer driver. 'lp=reset' (which can be
  732. specified in addition to the ports) causes
  733. attached printers to be reset. Using
  734. lp=port1,port2,... specifies the parallel ports
  735. to associate lp devices with, starting with
  736. lp0. A port specification may be 'none' to skip
  737. that lp device, or a parport name such as
  738. 'parport0'. Specifying 'lp=auto' instead of a
  739. port specification list means that device IDs
  740. from each port should be examined, to see if
  741. an IEEE 1284-compliant printer is attached; if
  742. so, the driver will manage that printer.
  743. See also header of drivers/char/lp.c.
  744. lpj=n [KNL]
  745. Sets loops_per_jiffy to given constant, thus avoiding
  746. time-consuming boot-time autodetection (up to 250 ms per
  747. CPU). 0 enables autodetection (default). To determine
  748. the correct value for your kernel, boot with normal
  749. autodetection and see what value is printed. Note that
  750. on SMP systems the preset will be applied to all CPUs,
  751. which is likely to cause problems if your CPUs need
  752. significantly divergent settings. An incorrect value
  753. will cause delays in the kernel to be wrong, leading to
  754. unpredictable I/O errors and other breakage. Although
  755. unlikely, in the extreme case this might damage your
  756. hardware.
  757. ltpc= [NET]
  758. Format: <io>,<irq>,<dma>
  759. mac5380= [HW,SCSI] Format:
  760. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  761. mac53c9x= [HW,SCSI] Format:
  762. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  763. machvec= [IA64] Force the use of a particular machine-vector
  764. (machvec) in a generic kernel.
  765. Example: machvec=hpzx1_swiotlb
  766. max_loop= [LOOP] Maximum number of loopback devices that can
  767. be mounted
  768. Format: <1-256>
  769. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  770. should make use of. maxcpus=n : n >= 0 limits the
  771. kernel to using 'n' processors. n=0 is a special case,
  772. it is equivalent to "nosmp", which also disables
  773. the IO APIC.
  774. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  775. equal to this physical address is ignored.
  776. max_luns= [SCSI] Maximum number of LUNs to probe.
  777. Should be between 1 and 2^32-1.
  778. max_report_luns=
  779. [SCSI] Maximum number of LUNs received.
  780. Should be between 1 and 16384.
  781. mca-pentium [BUGS=X86-32]
  782. mcatest= [IA-64]
  783. mce [X86-32] Machine Check Exception
  784. mce=option [X86-64] See Documentation/x86_64/boot-options.txt
  785. md= [HW] RAID subsystems devices and level
  786. See Documentation/md.txt.
  787. mdacon= [MDA]
  788. Format: <first>,<last>
  789. Specifies range of consoles to be captured by the MDA.
  790. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  791. Amount of memory to be used when the kernel is not able
  792. to see the whole system memory or for test.
  793. [X86-32] Use together with memmap= to avoid physical
  794. address space collisions. Without memmap= PCI devices
  795. could be placed at addresses belonging to unused RAM.
  796. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  797. memory.
  798. memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
  799. E820 memory map, as specified by the user.
  800. Such memmap=exactmap lines can be constructed based on
  801. BIOS output or other requirements. See the memmap=nn@ss
  802. option description.
  803. memmap=nn[KMG]@ss[KMG]
  804. [KNL] Force usage of a specific region of memory
  805. Region of memory to be used, from ss to ss+nn.
  806. memmap=nn[KMG]#ss[KMG]
  807. [KNL,ACPI] Mark specific memory as ACPI data.
  808. Region of memory to be used, from ss to ss+nn.
  809. memmap=nn[KMG]$ss[KMG]
  810. [KNL,ACPI] Mark specific memory as reserved.
  811. Region of memory to be used, from ss to ss+nn.
  812. meye.*= [HW] Set MotionEye Camera parameters
  813. See Documentation/video4linux/meye.txt.
  814. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  815. Multi-Function General Purpose Timers on AMD Geode
  816. platforms.
  817. mga= [HW,DRM]
  818. mousedev.tap_time=
  819. [MOUSE] Maximum time between finger touching and
  820. leaving touchpad surface for touch to be considered
  821. a tap and be reported as a left button click (for
  822. touchpads working in absolute mode only).
  823. Format: <msecs>
  824. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  825. reporting absolute coordinates, such as tablets
  826. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  827. reporting absolute coordinates, such as tablets
  828. mpu401= [HW,OSS]
  829. Format: <io>,<irq>
  830. MTD_Partition= [MTD]
  831. Format: <name>,<region-number>,<size>,<offset>
  832. MTD_Region= [MTD] Format:
  833. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  834. mtdparts= [MTD]
  835. See drivers/mtd/cmdlinepart.c.
  836. mtouchusb.raw_coordinates=
  837. [HW] Make the MicroTouch USB driver use raw coordinates
  838. ('y', default) or cooked coordinates ('n')
  839. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  840. NCR_D700= [HW,SCSI]
  841. See header of drivers/scsi/NCR_D700.c.
  842. ncr5380= [HW,SCSI]
  843. ncr53c400= [HW,SCSI]
  844. ncr53c400a= [HW,SCSI]
  845. ncr53c406a= [HW,SCSI]
  846. ncr53c8xx= [HW,SCSI]
  847. netdev= [NET] Network devices parameters
  848. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  849. Note that mem_start is often overloaded to mean
  850. something different and driver-specific.
  851. This usage is only documented in each driver source
  852. file if at all.
  853. nfsaddrs= [NFS]
  854. See Documentation/nfsroot.txt.
  855. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  856. See Documentation/nfsroot.txt.
  857. nfs.callback_tcpport=
  858. [NFS] set the TCP port on which the NFSv4 callback
  859. channel should listen.
  860. nfs.idmap_cache_timeout=
  861. [NFS] set the maximum lifetime for idmapper cache
  862. entries.
  863. nfs.enable_ino64=
  864. [NFS] enable 64-bit inode numbers.
  865. If zero, the NFS client will fake up a 32-bit inode
  866. number for the readdir() and stat() syscalls instead
  867. of returning the full 64-bit number.
  868. The default is to return 64-bit inode numbers.
  869. nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
  870. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  871. emulation library even if a 387 maths coprocessor
  872. is present.
  873. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  874. caches in the slab allocator. Saves per-node memory,
  875. but will impact performance.
  876. noalign [KNL,ARM]
  877. noapic [SMP,APIC] Tells the kernel to not make use of any
  878. IOAPICs that may be present in the system.
  879. nobats [PPC] Do not use BATs for mapping kernel lowmem
  880. on "Classic" PPC cores.
  881. nocache [ARM]
  882. nodelayacct [KNL] Disable per-task delay accounting
  883. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  884. noexec [IA-64]
  885. noexec [X86-32,X86-64]
  886. noexec=on: enable non-executable mappings (default)
  887. noexec=off: disable nn-executable mappings
  888. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  889. register save and restore. The kernel will only save
  890. legacy floating-point registers on task switch.
  891. nohlt [BUGS=ARM]
  892. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  893. instruction doesn't work correctly and not to
  894. use it.
  895. nohalt [IA-64] Tells the kernel not to use the power saving
  896. function PAL_HALT_LIGHT when idle. This increases
  897. power-consumption. On the positive side, it reduces
  898. interrupt wake-up latency, which may improve performance
  899. in certain environments such as networked servers or
  900. real-time systems.
  901. nohz= [KNL] Boottime enable/disable dynamic ticks
  902. Valid arguments: on, off
  903. Default: on
  904. noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
  905. noirqdebug [X86-32] Disables the code which attempts to detect and
  906. disable unhandled interrupt sources.
  907. no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
  908. broken timer IRQ sources.
  909. noisapnp [ISAPNP] Disables ISA PnP code.
  910. noinitrd [RAM] Tells the kernel not to load any configured
  911. initial RAM disk.
  912. nointroute [IA-64]
  913. nojitter [IA64] Disables jitter checking for ITC timers.
  914. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  915. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  916. noltlbs [PPC] Do not use large page/tlb entries for kernel
  917. lowmem mapping on PPC40x.
  918. nomca [IA-64] Disable machine check abort handling
  919. nomce [X86-32] Machine Check Exception
  920. nomfgpt [X86-32] Disable Multi-Function General Purpose
  921. Timer usage (for AMD Geode machines).
  922. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  923. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  924. with UP alternatives
  925. noresidual [PPC] Don't use residual data on PReP machines.
  926. noresume [SWSUSP] Disables resume and restores original swap
  927. space.
  928. no-scroll [VGA] Disables scrollback.
  929. This is required for the Braillex ib80-piezo Braille
  930. reader made by F.H. Papenmeier (Germany).
  931. nosbagart [IA-64]
  932. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  933. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  934. and disable the IO APIC. legacy for "maxcpus=0".
  935. nosoftlockup [KNL] Disable the soft-lockup detector.
  936. nosync [HW,M68K] Disables sync negotiation for all devices.
  937. notsc [BUGS=X86-32] Disable Time Stamp Counter
  938. nousb [USB] Disable the USB subsystem
  939. nowb [ARM]
  940. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  941. one of ['zone', 'node', 'default'] can be specified
  942. This can be set from sysctl after boot.
  943. See Documentation/sysctl/vm.txt for details.
  944. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  945. opl3= [HW,OSS]
  946. Format: <io>
  947. oprofile.timer= [HW]
  948. Use timer interrupt instead of performance counters
  949. osst= [HW,SCSI] SCSI Tape Driver
  950. Format: <buffer_size>,<write_threshold>
  951. See also Documentation/scsi/st.txt.
  952. panic= [KNL] Kernel behaviour on panic
  953. Format: <timeout>
  954. parkbd.port= [HW] Parallel port number the keyboard adapter is
  955. connected to, default is 0.
  956. Format: <parport#>
  957. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  958. 0 for XT, 1 for AT (default is AT).
  959. Format: <mode>
  960. parport= [HW,PPT] Specify parallel ports. 0 disables.
  961. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  962. Use 'auto' to force the driver to use any
  963. IRQ/DMA settings detected (the default is to
  964. ignore detected IRQ/DMA settings because of
  965. possible conflicts). You can specify the base
  966. address, IRQ, and DMA settings; IRQ and DMA
  967. should be numbers, or 'auto' (for using detected
  968. settings on that particular port), or 'nofifo'
  969. (to avoid using a FIFO even if it is detected).
  970. Parallel ports are assigned in the order they
  971. are specified on the command line, starting
  972. with parport0.
  973. parport_init_mode= [HW,PPT]
  974. Configure VIA parallel port to operate in
  975. a specific mode. This is necessary on Pegasos
  976. computer where firmware has no options for setting
  977. up parallel port mode and sets it to spp.
  978. Currently this function knows 686a and 8231 chips.
  979. Format: [spp|ps2|epp|ecp|ecpepp]
  980. pas2= [HW,OSS] Format:
  981. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  982. pas16= [HW,SCSI]
  983. See header of drivers/scsi/pas16.c.
  984. pause_on_oops=
  985. Halt all CPUs after the first oops has been printed for
  986. the specified number of seconds. This is to be used if
  987. your oopses keep scrolling off the screen.
  988. pcbit= [HW,ISDN]
  989. pcd. [PARIDE]
  990. See header of drivers/block/paride/pcd.c.
  991. See also Documentation/paride.txt.
  992. pci=option[,option...] [PCI] various PCI subsystem options:
  993. off [X86-32] don't probe for the PCI bus
  994. bios [X86-32] force use of PCI BIOS, don't access
  995. the hardware directly. Use this if your machine
  996. has a non-standard PCI host bridge.
  997. nobios [X86-32] disallow use of PCI BIOS, only direct
  998. hardware access methods are allowed. Use this
  999. if you experience crashes upon bootup and you
  1000. suspect they are caused by the BIOS.
  1001. conf1 [X86-32] Force use of PCI Configuration
  1002. Mechanism 1.
  1003. conf2 [X86-32] Force use of PCI Configuration
  1004. Mechanism 2.
  1005. noaer [PCIE] If the PCIEAER kernel config parameter is
  1006. enabled, this kernel boot option can be used to
  1007. disable the use of PCIE advanced error reporting.
  1008. nodomains [PCI] Disable support for multiple PCI
  1009. root domains (aka PCI segments, in ACPI-speak).
  1010. nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
  1011. Configuration
  1012. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1013. enabled, this kernel boot option can be used to
  1014. disable the use of MSI interrupts system-wide.
  1015. nosort [X86-32] Don't sort PCI devices according to
  1016. order given by the PCI BIOS. This sorting is
  1017. done to get a device order compatible with
  1018. older kernels.
  1019. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1020. routing table. These calls are known to be buggy
  1021. on several machines and they hang the machine
  1022. when used, but on other computers it's the only
  1023. way to get the interrupt routing table. Try
  1024. this option if the kernel is unable to allocate
  1025. IRQs or discover secondary PCI buses on your
  1026. motherboard.
  1027. rom [X86-32] Assign address space to expansion ROMs.
  1028. Use with caution as certain devices share
  1029. address decoders between ROMs and other
  1030. resources.
  1031. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
  1032. assigned automatically to PCI devices. You can
  1033. make the kernel exclude IRQs of your ISA cards
  1034. this way.
  1035. pirqaddr=0xAAAAA [X86-32] Specify the physical address
  1036. of the PIRQ table (normally generated
  1037. by the BIOS) if it is outside the
  1038. F0000h-100000h range.
  1039. lastbus=N [X86-32] Scan all buses thru bus #N. Can be
  1040. useful if the kernel is unable to find your
  1041. secondary buses and you want to tell it
  1042. explicitly which ones they are.
  1043. assign-busses [X86-32] Always assign all PCI bus
  1044. numbers ourselves, overriding
  1045. whatever the firmware may have done.
  1046. usepirqmask [X86-32] Honor the possible IRQ mask stored
  1047. in the BIOS $PIR table. This is needed on
  1048. some systems with broken BIOSes, notably
  1049. some HP Pavilion N5400 and Omnibook XE3
  1050. notebooks. This will have no effect if ACPI
  1051. IRQ routing is enabled.
  1052. noacpi [X86-32] Do not use ACPI for IRQ routing
  1053. or for PCI scanning.
  1054. use_crs [X86-32] Use _CRS for PCI resource
  1055. allocation.
  1056. routeirq Do IRQ routing for all PCI devices.
  1057. This is normally done in pci_enable_device(),
  1058. so this option is a temporary workaround
  1059. for broken drivers that don't call it.
  1060. firmware [ARM] Do not re-enumerate the bus but instead
  1061. just use the configuration from the
  1062. bootloader. This is currently used on
  1063. IXP2000 systems where the bus has to be
  1064. configured a certain way for adjunct CPUs.
  1065. noearly [X86] Don't do any early type 1 scanning.
  1066. This might help on some broken boards which
  1067. machine check when some devices' config space
  1068. is read. But various workarounds are disabled
  1069. and some IOMMU drivers will not work.
  1070. bfsort Sort PCI devices into breadth-first order.
  1071. This sorting is done to get a device
  1072. order compatible with older (<= 2.4) kernels.
  1073. nobfsort Don't sort PCI devices into breadth-first order.
  1074. cbiosize=nn[KMG] The fixed amount of bus space which is
  1075. reserved for the CardBus bridge's IO window.
  1076. The default value is 256 bytes.
  1077. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1078. reserved for the CardBus bridge's memory
  1079. window. The default value is 64 megabytes.
  1080. pcmv= [HW,PCMCIA] BadgePAD 4
  1081. pd. [PARIDE]
  1082. See Documentation/paride.txt.
  1083. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1084. boot time.
  1085. Format: { 0 | 1 }
  1086. See arch/parisc/kernel/pdc_chassis.c
  1087. pf. [PARIDE]
  1088. See Documentation/paride.txt.
  1089. pg. [PARIDE]
  1090. See Documentation/paride.txt.
  1091. pirq= [SMP,APIC] Manual mp-table setup
  1092. See Documentation/i386/IO-APIC.txt.
  1093. plip= [PPT,NET] Parallel port network link
  1094. Format: { parport<nr> | timid | 0 }
  1095. See also Documentation/parport.txt.
  1096. pnpacpi= [ACPI]
  1097. { off }
  1098. pnpbios= [ISAPNP]
  1099. { on | off | curr | res | no-curr | no-res }
  1100. pnp_reserve_irq=
  1101. [ISAPNP] Exclude IRQs for the autoconfiguration
  1102. pnp_reserve_dma=
  1103. [ISAPNP] Exclude DMAs for the autoconfiguration
  1104. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1105. Ranges are in pairs (I/O port base and size).
  1106. pnp_reserve_mem=
  1107. [ISAPNP] Exclude memory regions for the
  1108. autoconfiguration.
  1109. Ranges are in pairs (memory base and size).
  1110. print-fatal-signals=
  1111. [KNL] debug: print fatal signals
  1112. print-fatal-signals=1: print segfault info to
  1113. the kernel console.
  1114. default: off.
  1115. printk.time= Show timing data prefixed to each printk message line
  1116. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1117. profile= [KNL] Enable kernel profiling via /proc/profile
  1118. Format: [schedule,]<number>
  1119. Param: "schedule" - profile schedule points.
  1120. Param: <number> - step/bucket size as a power of 2 for
  1121. statistical time based profiling.
  1122. Param: "sleep" - profile D-state sleeping (millisecs)
  1123. Param: "kvm" - profile VM exits.
  1124. processor.max_cstate= [HW,ACPI]
  1125. Limit processor to maximum C-state
  1126. max_cstate=9 overrides any DMI blacklist limit.
  1127. processor.nocst [HW,ACPI]
  1128. Ignore the _CST method to determine C-states,
  1129. instead using the legacy FADT method
  1130. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1131. before loading.
  1132. See Documentation/ramdisk.txt.
  1133. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1134. probe for; one of (bare|imps|exps|lifebook|any).
  1135. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1136. per second.
  1137. psmouse.resetafter= [HW,MOUSE]
  1138. Try to reset the device after so many bad packets
  1139. (0 = never).
  1140. psmouse.resolution=
  1141. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1142. psmouse.smartscroll=
  1143. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1144. 0 = disabled, 1 = enabled (default).
  1145. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1146. Format:
  1147. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1148. pt. [PARIDE]
  1149. See Documentation/paride.txt.
  1150. pty.legacy_count=
  1151. [KNL] Number of legacy pty's. Overwrites compiled-in
  1152. default number.
  1153. quiet [KNL] Disable most log messages
  1154. r128= [HW,DRM]
  1155. raid= [HW,RAID]
  1156. See Documentation/md.txt.
  1157. ramdisk_blocksize= [RAM]
  1158. See Documentation/ramdisk.txt.
  1159. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1160. See Documentation/ramdisk.txt.
  1161. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1162. RCU callbacks to process in one batch.
  1163. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1164. RCU callbacks over which batch limiting is disabled.
  1165. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1166. RCU callbacks below which batch limiting is re-enabled.
  1167. rdinit= [KNL]
  1168. Format: <full_path>
  1169. Run specified binary instead of /init from the ramdisk,
  1170. used for early userspace startup. See initrd.
  1171. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1172. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1173. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1174. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1175. reservetop= [X86-32]
  1176. Format: nn[KMG]
  1177. Reserves a hole at the top of the kernel virtual
  1178. address space.
  1179. reset_devices [KNL] Force drivers to reset the underlying device
  1180. during initialization.
  1181. resume= [SWSUSP]
  1182. Specify the partition device for software suspend
  1183. resume_offset= [SWSUSP]
  1184. Specify the offset from the beginning of the partition
  1185. given by "resume=" at which the swap header is located,
  1186. in <PAGE_SIZE> units (needed only for swap files).
  1187. See Documentation/power/swsusp-and-swap-files.txt
  1188. retain_initrd [RAM] Keep initrd memory after extraction
  1189. rhash_entries= [KNL,NET]
  1190. Set number of hash buckets for route cache
  1191. riscom8= [HW,SERIAL]
  1192. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1193. ro [KNL] Mount root device read-only on boot
  1194. root= [KNL] Root filesystem
  1195. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1196. mount the root filesystem
  1197. rootflags= [KNL] Set root filesystem mount option string
  1198. rootfstype= [KNL] Set root filesystem type
  1199. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1200. Useful for devices that are detected asynchronously
  1201. (e.g. USB and MMC devices).
  1202. root_plug.vendor_id=
  1203. [ROOTPLUG] Override the default vendor ID
  1204. root_plug.product_id=
  1205. [ROOTPLUG] Override the default product ID
  1206. root_plug.debug=
  1207. [ROOTPLUG] Enable debugging output
  1208. rw [KNL] Mount root device read-write on boot
  1209. S [KNL] Run init in single mode
  1210. sa1100ir [NET]
  1211. See drivers/net/irda/sa1100_ir.c.
  1212. sbni= [NET] Granch SBNI12 leased line adapter
  1213. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1214. Format: <io>[,<timeout>[,<isapnp>]]
  1215. scsi_debug_*= [SCSI]
  1216. See drivers/scsi/scsi_debug.c.
  1217. scsi_default_dev_flags=
  1218. [SCSI] SCSI default device flags
  1219. Format: <integer>
  1220. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1221. Format: <vendor>:<model>:<flags>
  1222. (flags are integer value)
  1223. scsi_logging= [SCSI]
  1224. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1225. discovered. async scans them in kernel threads,
  1226. allowing boot to proceed. none ignores them, expecting
  1227. user space to do the scan.
  1228. selinux [SELINUX] Disable or enable SELinux at boot time.
  1229. Format: { "0" | "1" }
  1230. See security/selinux/Kconfig help text.
  1231. 0 -- disable.
  1232. 1 -- enable.
  1233. Default value is set via kernel config option.
  1234. If enabled at boot time, /selinux/disable can be used
  1235. later to disable prior to initial policy load.
  1236. selinux_compat_net =
  1237. [SELINUX] Set initial selinux_compat_net flag value.
  1238. Format: { "0" | "1" }
  1239. 0 -- use new secmark-based packet controls
  1240. 1 -- use legacy packet controls
  1241. Default value is 0 (preferred).
  1242. Value can be changed at runtime via
  1243. /selinux/compat_net.
  1244. serialnumber [BUGS=X86-32]
  1245. shapers= [NET]
  1246. Maximal number of shapers.
  1247. sim710= [SCSI,HW]
  1248. See header of drivers/scsi/sim710.c.
  1249. simeth= [IA-64]
  1250. simscsi=
  1251. slram= [HW,MTD]
  1252. slub_debug[=options[,slabs]] [MM, SLUB]
  1253. Enabling slub_debug allows one to determine the
  1254. culprit if slab objects become corrupted. Enabling
  1255. slub_debug can create guard zones around objects and
  1256. may poison objects when not in use. Also tracks the
  1257. last alloc / free. For more information see
  1258. Documentation/vm/slub.txt.
  1259. slub_max_order= [MM, SLUB]
  1260. Determines the maximum allowed order for slabs.
  1261. A high setting may cause OOMs due to memory
  1262. fragmentation. For more information see
  1263. Documentation/vm/slub.txt.
  1264. slub_min_objects= [MM, SLUB]
  1265. The minimum number of objects per slab. SLUB will
  1266. increase the slab order up to slub_max_order to
  1267. generate a sufficiently large slab able to contain
  1268. the number of objects indicated. The higher the number
  1269. of objects the smaller the overhead of tracking slabs
  1270. and the less frequently locks need to be acquired.
  1271. For more information see Documentation/vm/slub.txt.
  1272. slub_min_order= [MM, SLUB]
  1273. Determines the mininum page order for slabs. Must be
  1274. lower than slub_max_order.
  1275. For more information see Documentation/vm/slub.txt.
  1276. slub_nomerge [MM, SLUB]
  1277. Disable merging of slabs with similar size. May be
  1278. necessary if there is some reason to distinguish
  1279. allocs to different slabs. Debug options disable
  1280. merging on their own.
  1281. For more information see Documentation/vm/slub.txt.
  1282. smart2= [HW]
  1283. Format: <io1>[,<io2>[,...,<io8>]]
  1284. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1285. attempt to substitute SMP alternatives once at boot.
  1286. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1287. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1288. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1289. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1290. smsc-ircc2.ircc_irq= [HW] IRQ line
  1291. smsc-ircc2.ircc_dma= [HW] DMA channel
  1292. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1293. 0: Toshiba Satellite 1800 (GP data pin select)
  1294. 1: Fast pin select (default)
  1295. 2: ATC IRMode
  1296. snd-ad1816a= [HW,ALSA]
  1297. snd-ad1848= [HW,ALSA]
  1298. snd-ali5451= [HW,ALSA]
  1299. snd-als100= [HW,ALSA]
  1300. snd-als4000= [HW,ALSA]
  1301. snd-azt2320= [HW,ALSA]
  1302. snd-cmi8330= [HW,ALSA]
  1303. snd-cmipci= [HW,ALSA]
  1304. snd-cs4231= [HW,ALSA]
  1305. snd-cs4232= [HW,ALSA]
  1306. snd-cs4236= [HW,ALSA]
  1307. snd-cs4281= [HW,ALSA]
  1308. snd-cs46xx= [HW,ALSA]
  1309. snd-dt019x= [HW,ALSA]
  1310. snd-dummy= [HW,ALSA]
  1311. snd-emu10k1= [HW,ALSA]
  1312. snd-ens1370= [HW,ALSA]
  1313. snd-ens1371= [HW,ALSA]
  1314. snd-es968= [HW,ALSA]
  1315. snd-es1688= [HW,ALSA]
  1316. snd-es18xx= [HW,ALSA]
  1317. snd-es1938= [HW,ALSA]
  1318. snd-es1968= [HW,ALSA]
  1319. snd-fm801= [HW,ALSA]
  1320. snd-gusclassic= [HW,ALSA]
  1321. snd-gusextreme= [HW,ALSA]
  1322. snd-gusmax= [HW,ALSA]
  1323. snd-hdsp= [HW,ALSA]
  1324. snd-ice1712= [HW,ALSA]
  1325. snd-intel8x0= [HW,ALSA]
  1326. snd-interwave= [HW,ALSA]
  1327. snd-interwave-stb=
  1328. [HW,ALSA]
  1329. snd-korg1212= [HW,ALSA]
  1330. snd-maestro3= [HW,ALSA]
  1331. snd-mpu401= [HW,ALSA]
  1332. snd-mtpav= [HW,ALSA]
  1333. snd-nm256= [HW,ALSA]
  1334. snd-opl3sa2= [HW,ALSA]
  1335. snd-opti92x-ad1848=
  1336. [HW,ALSA]
  1337. snd-opti92x-cs4231=
  1338. [HW,ALSA]
  1339. snd-opti93x= [HW,ALSA]
  1340. snd-pmac= [HW,ALSA]
  1341. snd-rme32= [HW,ALSA]
  1342. snd-rme96= [HW,ALSA]
  1343. snd-rme9652= [HW,ALSA]
  1344. snd-sb8= [HW,ALSA]
  1345. snd-sb16= [HW,ALSA]
  1346. snd-sbawe= [HW,ALSA]
  1347. snd-serial= [HW,ALSA]
  1348. snd-sgalaxy= [HW,ALSA]
  1349. snd-sonicvibes= [HW,ALSA]
  1350. snd-sun-amd7930=
  1351. [HW,ALSA]
  1352. snd-sun-cs4231= [HW,ALSA]
  1353. snd-trident= [HW,ALSA]
  1354. snd-usb-audio= [HW,ALSA,USB]
  1355. snd-via82xx= [HW,ALSA]
  1356. snd-virmidi= [HW,ALSA]
  1357. snd-wavefront= [HW,ALSA]
  1358. snd-ymfpci= [HW,ALSA]
  1359. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1360. See Documentation/sonypi.txt
  1361. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1362. See Documentation/specialix.txt.
  1363. spia_io_base= [HW,MTD]
  1364. spia_fio_base=
  1365. spia_pedr=
  1366. spia_peddr=
  1367. sscape= [HW,OSS]
  1368. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1369. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1370. See Documentation/scsi/st.txt.
  1371. st0x= [HW,SCSI]
  1372. See header of drivers/scsi/seagate.c.
  1373. sti= [PARISC,HW]
  1374. Format: <num>
  1375. Set the STI (builtin display/keyboard on the HP-PARISC
  1376. machines) console (graphic card) which should be used
  1377. as the initial boot-console.
  1378. See also comment in drivers/video/console/sticore.c.
  1379. sti_font= [HW]
  1380. See comment in drivers/video/console/sticore.c.
  1381. stifb= [HW]
  1382. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1383. sunrpc.pool_mode=
  1384. [NFS]
  1385. Control how the NFS server code allocates CPUs to
  1386. service thread pools. Depending on how many NICs
  1387. you have and where their interrupts are bound, this
  1388. option will affect which CPUs will do NFS serving.
  1389. Note: this parameter cannot be changed while the
  1390. NFS server is running.
  1391. auto the server chooses an appropriate mode
  1392. automatically using heuristics
  1393. global a single global pool contains all CPUs
  1394. percpu one pool for each CPU
  1395. pernode one pool for each NUMA node (equivalent
  1396. to global on non-NUMA machines)
  1397. swiotlb= [IA-64] Number of I/O TLB slabs
  1398. switches= [HW,M68k]
  1399. sym53c416= [HW,SCSI]
  1400. See header of drivers/scsi/sym53c416.c.
  1401. sysrq_always_enabled
  1402. [KNL]
  1403. Ignore sysrq setting - this boot parameter will
  1404. neutralize any effect of /proc/sys/kernel/sysrq.
  1405. Useful for debugging.
  1406. t128= [HW,SCSI]
  1407. See header of drivers/scsi/t128.c.
  1408. tdfx= [HW,DRM]
  1409. thash_entries= [KNL,NET]
  1410. Set number of hash buckets for TCP connection
  1411. thermal.act= [HW,ACPI]
  1412. -1: disable all active trip points in all thermal zones
  1413. <degrees C>: override all lowest active trip points
  1414. thermal.crt= [HW,ACPI]
  1415. -1: disable all critical trip points in all thermal zones
  1416. <degrees C>: lower all critical trip points
  1417. thermal.nocrt= [HW,ACPI]
  1418. Set to disable actions on ACPI thermal zone
  1419. critical and hot trip points.
  1420. thermal.off= [HW,ACPI]
  1421. 1: disable ACPI thermal control
  1422. thermal.psv= [HW,ACPI]
  1423. -1: disable all passive trip points
  1424. <degrees C>: override all passive trip points to this value
  1425. thermal.tzp= [HW,ACPI]
  1426. Specify global default ACPI thermal zone polling rate
  1427. <deci-seconds>: poll all this frequency
  1428. 0: no polling (default)
  1429. time Show timing data prefixed to each printk message line
  1430. [deprecated, see 'printk.time']
  1431. tipar.timeout= [HW,PPT]
  1432. Set communications timeout in tenths of a second
  1433. (default 15).
  1434. tipar.delay= [HW,PPT]
  1435. Set inter-bit delay in microseconds (default 10).
  1436. tmc8xx= [HW,SCSI]
  1437. See header of drivers/scsi/seagate.c.
  1438. tmscsim= [HW,SCSI]
  1439. See comment before function dc390_setup() in
  1440. drivers/scsi/tmscsim.c.
  1441. tp720= [HW,PS2]
  1442. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1443. Format:
  1444. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1445. turbografx.map[2|3]= [HW,JOY]
  1446. TurboGraFX parallel port interface
  1447. Format:
  1448. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1449. See also Documentation/input/joystick-parport.txt
  1450. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1451. See header of drivers/scsi/u14-34f.c.
  1452. uart401= [HW,OSS]
  1453. Format: <io>,<irq>
  1454. uart6850= [HW,OSS]
  1455. Format: <io>,<irq>
  1456. uhci-hcd.ignore_oc=
  1457. [USB] Ignore overcurrent events (default N).
  1458. Some badly-designed motherboards generate lots of
  1459. bogus events, for ports that aren't wired to
  1460. anything. Set this parameter to avoid log spamming.
  1461. Note that genuine overcurrent events won't be
  1462. reported either.
  1463. usbcore.autosuspend=
  1464. [USB] The autosuspend time delay (in seconds) used
  1465. for newly-detected USB devices (default 2). This
  1466. is the time required before an idle device will be
  1467. autosuspended. Devices for which the delay is set
  1468. to a negative value won't be autosuspended at all.
  1469. usbhid.mousepoll=
  1470. [USBHID] The interval which mice are to be polled at.
  1471. vdso= [X86-32,SH,x86-64]
  1472. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1473. vdso=1: enable VDSO (default)
  1474. vdso=0: disable VDSO mapping
  1475. vector= [IA-64,SMP]
  1476. vector=percpu: enable percpu vector domain
  1477. video= [FB] Frame buffer configuration
  1478. See Documentation/fb/modedb.txt.
  1479. vga= [BOOT,X86-32] Select a particular video mode
  1480. See Documentation/i386/boot.txt and
  1481. Documentation/svga.txt.
  1482. Use vga=ask for menu.
  1483. This is actually a boot loader parameter; the value is
  1484. passed to the kernel using a special protocol.
  1485. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1486. size of <nn>. This can be used to increase the
  1487. minimum size (128MB on x86). It can also be used to
  1488. decrease the size and leave more room for directly
  1489. mapped kernel RAM.
  1490. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1491. Format: <command>
  1492. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1493. Format: <command>
  1494. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1495. Format: <command>
  1496. waveartist= [HW,OSS]
  1497. Format: <io>,<irq>,<dma>,<dma2>
  1498. wd33c93= [HW,SCSI]
  1499. See header of drivers/scsi/wd33c93.c.
  1500. wd7000= [HW,SCSI]
  1501. See header of drivers/scsi/wd7000.c.
  1502. wdt= [WDT] Watchdog
  1503. See Documentation/watchdog/wdt.txt.
  1504. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1505. xd_geo= See header of drivers/block/xd.c.
  1506. xirc2ps_cs= [NET,PCMCIA]
  1507. Format:
  1508. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1509. norandmaps Don't use address space randomization
  1510. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1511. ______________________________________________________________________
  1512. TODO:
  1513. Add documentation for ALSA options.
  1514. Add more DRM drivers.