kernel-parameters.txt 82 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402140314041405140614071408140914101411141214131414141514161417141814191420142114221423142414251426142714281429143014311432143314341435143614371438143914401441144214431444144514461447144814491450145114521453145414551456145714581459146014611462146314641465146614671468146914701471147214731474147514761477147814791480148114821483148414851486148714881489149014911492149314941495149614971498149915001501150215031504150515061507150815091510151115121513151415151516151715181519152015211522152315241525152615271528152915301531153215331534153515361537153815391540154115421543154415451546154715481549155015511552155315541555155615571558155915601561156215631564156515661567156815691570157115721573157415751576157715781579158015811582158315841585158615871588158915901591159215931594159515961597159815991600160116021603160416051606160716081609161016111612161316141615161616171618161916201621162216231624162516261627162816291630163116321633163416351636163716381639164016411642164316441645164616471648164916501651165216531654165516561657165816591660166116621663166416651666166716681669167016711672167316741675167616771678167916801681168216831684168516861687168816891690169116921693169416951696169716981699170017011702170317041705170617071708170917101711171217131714171517161717171817191720172117221723172417251726172717281729173017311732173317341735173617371738173917401741174217431744174517461747174817491750175117521753175417551756175717581759176017611762176317641765176617671768176917701771177217731774177517761777177817791780178117821783178417851786178717881789179017911792179317941795179617971798179918001801180218031804180518061807180818091810181118121813181418151816181718181819182018211822182318241825182618271828182918301831183218331834183518361837183818391840184118421843184418451846184718481849185018511852185318541855185618571858185918601861186218631864186518661867186818691870187118721873187418751876187718781879188018811882188318841885188618871888188918901891189218931894189518961897189818991900190119021903190419051906190719081909191019111912191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939194019411942194319441945194619471948194919501951195219531954195519561957195819591960196119621963196419651966196719681969197019711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014201520162017201820192020202120222023202420252026202720282029203020312032203320342035203620372038203920402041204220432044204520462047204820492050205120522053205420552056205720582059206020612062206320642065206620672068206920702071207220732074207520762077207820792080208120822083208420852086208720882089209020912092209320942095209620972098209921002101210221032104210521062107210821092110211121122113211421152116211721182119212021212122212321242125212621272128212921302131213221332134213521362137213821392140214121422143214421452146214721482149215021512152215321542155215621572158215921602161216221632164216521662167216821692170217121722173217421752176217721782179218021812182218321842185218621872188218921902191219221932194219521962197219821992200220122022203220422052206220722082209221022112212221322142215221622172218221922202221222222232224222522262227222822292230223122322233223422352236223722382239224022412242224322442245224622472248224922502251225222532254225522562257225822592260226122622263226422652266226722682269227022712272227322742275227622772278227922802281228222832284228522862287228822892290229122922293229422952296229722982299230023012302230323042305230623072308230923102311231223132314231523162317231823192320232123222323232423252326232723282329233023312332233323342335233623372338233923402341234223432344234523462347234823492350235123522353235423552356235723582359236023612362236323642365236623672368236923702371237223732374237523762377237823792380238123822383238423852386238723882389239023912392239323942395239623972398239924002401240224032404240524062407240824092410241124122413241424152416241724182419242024212422242324242425242624272428242924302431243224332434243524362437243824392440244124422443244424452446244724482449245024512452245324542455245624572458245924602461246224632464246524662467246824692470247124722473247424752476247724782479248024812482248324842485248624872488248924902491249224932494249524962497249824992500250125022503250425052506250725082509251025112512251325142515251625172518251925202521252225232524252525262527252825292530253125322533253425352536253725382539254025412542254325442545254625472548254925502551255225532554255525562557255825592560256125622563256425652566256725682569257025712572257325742575257625772578257925802581258225832584258525862587258825892590259125922593
  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. Hyphens (dashes) and underscores are equivalent in parameter names, so
  15. log_buf_len=1M print-fatal-signals=1
  16. can also be entered as
  17. log-buf-len=1M print_fatal_signals=1
  18. This document may not be entirely up to date and comprehensive. The command
  19. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  20. module. Loadable modules, after being loaded into the running kernel, also
  21. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  22. parameters may be changed at runtime by the command
  23. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  24. The parameters listed below are only valid if certain kernel build options were
  25. enabled and if respective hardware is present. The text in square brackets at
  26. the beginning of each description states the restrictions within which a
  27. parameter is applicable:
  28. ACPI ACPI support is enabled.
  29. AGP AGP (Accelerated Graphics Port) is enabled.
  30. ALSA ALSA sound support is enabled.
  31. APIC APIC support is enabled.
  32. APM Advanced Power Management support is enabled.
  33. AVR32 AVR32 architecture is enabled.
  34. AX25 Appropriate AX.25 support is enabled.
  35. BLACKFIN Blackfin architecture is enabled.
  36. DRM Direct Rendering Management support is enabled.
  37. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  38. EFI EFI Partitioning (GPT) is enabled
  39. EIDE EIDE/ATAPI support is enabled.
  40. FB The frame buffer device is enabled.
  41. HW Appropriate hardware is enabled.
  42. IA-64 IA-64 architecture is enabled.
  43. IMA Integrity measurement architecture is enabled.
  44. IOSCHED More than one I/O scheduler is enabled.
  45. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  46. ISAPNP ISA PnP code is enabled.
  47. ISDN Appropriate ISDN support is enabled.
  48. JOY Appropriate joystick support is enabled.
  49. KMEMTRACE kmemtrace is enabled.
  50. LIBATA Libata driver is enabled
  51. LP Printer support is enabled.
  52. LOOP Loopback device support is enabled.
  53. M68k M68k architecture is enabled.
  54. These options have more detailed description inside of
  55. Documentation/m68k/kernel-options.txt.
  56. MCA MCA bus support is enabled.
  57. MDA MDA console support is enabled.
  58. MOUSE Appropriate mouse support is enabled.
  59. MSI Message Signaled Interrupts (PCI).
  60. MTD MTD (Memory Technology Device) support is enabled.
  61. NET Appropriate network support is enabled.
  62. NUMA NUMA support is enabled.
  63. GENERIC_TIME The generic timeofday code is enabled.
  64. NFS Appropriate NFS support is enabled.
  65. OSS OSS sound support is enabled.
  66. PV_OPS A paravirtualized kernel is enabled.
  67. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  68. PARISC The PA-RISC architecture is enabled.
  69. PCI PCI bus support is enabled.
  70. PCIE PCI Express support is enabled.
  71. PCMCIA The PCMCIA subsystem is enabled.
  72. PNP Plug & Play support is enabled.
  73. PPC PowerPC architecture is enabled.
  74. PPT Parallel port support is enabled.
  75. PS2 Appropriate PS/2 support is enabled.
  76. RAM RAM disk support is enabled.
  77. ROOTPLUG The example Root Plug LSM is enabled.
  78. S390 S390 architecture is enabled.
  79. SCSI Appropriate SCSI support is enabled.
  80. A lot of drivers has their options described inside of
  81. Documentation/scsi/.
  82. SECURITY Different security models are enabled.
  83. SELINUX SELinux support is enabled.
  84. SERIAL Serial support is enabled.
  85. SH SuperH architecture is enabled.
  86. SMP The kernel is an SMP kernel.
  87. SPARC Sparc architecture is enabled.
  88. SWSUSP Software suspend (hibernation) is enabled.
  89. SUSPEND System suspend states are enabled.
  90. FTRACE Function tracing enabled.
  91. TS Appropriate touchscreen support is enabled.
  92. UMS USB Mass Storage support is enabled.
  93. USB USB support is enabled.
  94. USBHID USB Human Interface Device support is enabled.
  95. V4L Video For Linux support is enabled.
  96. VGA The VGA console has been enabled.
  97. VT Virtual terminal support is enabled.
  98. WDT Watchdog support is enabled.
  99. XT IBM PC/XT MFM hard disk support is enabled.
  100. X86-32 X86-32, aka i386 architecture is enabled.
  101. X86-64 X86-64 architecture is enabled.
  102. More X86-64 boot options can be found in
  103. Documentation/x86/x86_64/boot-options.txt .
  104. X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
  105. In addition, the following text indicates that the option:
  106. BUGS= Relates to possible processor bugs on the said processor.
  107. KNL Is a kernel start-up parameter.
  108. BOOT Is a boot loader parameter.
  109. Parameters denoted with BOOT are actually interpreted by the boot
  110. loader, and have no meaning to the kernel directly.
  111. Do not modify the syntax of boot loader parameters without extreme
  112. need or coordination with <Documentation/x86/boot.txt>.
  113. There are also arch-specific kernel-parameters not documented here.
  114. See for example <Documentation/x86/x86_64/boot-options.txt>.
  115. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  116. a trailing = on the name of any parameter states that that parameter will
  117. be entered as an environment variable, whereas its absence indicates that
  118. it will appear as a kernel argument readable via /proc/cmdline by programs
  119. running once the system is up.
  120. The number of kernel parameters is not limited, but the length of the
  121. complete command line (parameters including spaces etc.) is limited to
  122. a fixed number of characters. This limit depends on the architecture
  123. and is between 256 and 4096 characters. It is defined in the file
  124. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  125. acpi= [HW,ACPI,X86]
  126. Advanced Configuration and Power Interface
  127. Format: { force | off | ht | strict | noirq | rsdt }
  128. force -- enable ACPI if default was off
  129. off -- disable ACPI if default was on
  130. noirq -- do not use ACPI for IRQ routing
  131. ht -- run only enough ACPI to enable Hyper Threading
  132. strict -- Be less tolerant of platforms that are not
  133. strictly ACPI specification compliant.
  134. rsdt -- prefer RSDT over (default) XSDT
  135. See also Documentation/power/pm.txt, pci=noacpi
  136. acpi_apic_instance= [ACPI, IOAPIC]
  137. Format: <int>
  138. 2: use 2nd APIC table, if available
  139. 1,0: use 1st APIC table
  140. default: 0
  141. acpi_backlight= [HW,ACPI]
  142. acpi_backlight=vendor
  143. acpi_backlight=video
  144. If set to vendor, prefer vendor specific driver
  145. (e.g. thinkpad_acpi, sony_acpi, etc.) instead
  146. of the ACPI video.ko driver.
  147. acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
  148. acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
  149. Format: <int>
  150. CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
  151. debug output. Bits in debug_layer correspond to a
  152. _COMPONENT in an ACPI source file, e.g.,
  153. #define _COMPONENT ACPI_PCI_COMPONENT
  154. Bits in debug_level correspond to a level in
  155. ACPI_DEBUG_PRINT statements, e.g.,
  156. ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
  157. The debug_level mask defaults to "info". See
  158. Documentation/acpi/debug.txt for more information about
  159. debug layers and levels.
  160. Enable processor driver info messages:
  161. acpi.debug_layer=0x20000000
  162. Enable PCI/PCI interrupt routing info messages:
  163. acpi.debug_layer=0x400000
  164. Enable AML "Debug" output, i.e., stores to the Debug
  165. object while interpreting AML:
  166. acpi.debug_layer=0xffffffff acpi.debug_level=0x2
  167. Enable all messages related to ACPI hardware:
  168. acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
  169. Some values produce so much output that the system is
  170. unusable. The "log_buf_len" parameter may be useful
  171. if you need to capture more output.
  172. acpi_display_output= [HW,ACPI]
  173. acpi_display_output=vendor
  174. acpi_display_output=video
  175. See above.
  176. acpi_irq_balance [HW,ACPI]
  177. ACPI will balance active IRQs
  178. default in APIC mode
  179. acpi_irq_nobalance [HW,ACPI]
  180. ACPI will not move active IRQs (default)
  181. default in PIC mode
  182. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  183. Format: <irq>,<irq>...
  184. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  185. use by PCI
  186. Format: <irq>,<irq>...
  187. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  188. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  189. Format: To spoof as Windows 98: ="Microsoft Windows"
  190. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  191. acpi_osi="string1" # add string1 -- only one string
  192. acpi_osi="!string2" # remove built-in string2
  193. acpi_osi= # disable all strings
  194. acpi_pm_good [X86]
  195. Override the pmtimer bug detection: force the kernel
  196. to assume that this machine's pmtimer latches its value
  197. and always returns good values.
  198. acpi.power_nocheck= [HW,ACPI]
  199. Format: 1/0 enable/disable the check of power state.
  200. On some bogus BIOS the _PSC object/_STA object of
  201. power resource can't return the correct device power
  202. state. In such case it is unneccessary to check its
  203. power state again in power transition.
  204. 1 : disable the power state check
  205. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  206. Format: { level | edge | high | low }
  207. acpi_serialize [HW,ACPI] force serialization of AML methods
  208. acpi_skip_timer_override [HW,ACPI]
  209. Recognize and ignore IRQ0/pin2 Interrupt Override.
  210. For broken nForce2 BIOS resulting in XT-PIC timer.
  211. acpi_sleep= [HW,ACPI] Sleep options
  212. Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
  213. old_ordering, s4_nonvs }
  214. See Documentation/power/video.txt for information on
  215. s3_bios and s3_mode.
  216. s3_beep is for debugging; it makes the PC's speaker beep
  217. as soon as the kernel's real-mode entry point is called.
  218. s4_nohwsig prevents ACPI hardware signature from being
  219. used during resume from hibernation.
  220. old_ordering causes the ACPI 1.0 ordering of the _PTS
  221. control method, with respect to putting devices into
  222. low power states, to be enforced (the ACPI 2.0 ordering
  223. of _PTS is used by default).
  224. s4_nonvs prevents the kernel from saving/restoring the
  225. ACPI NVS memory during hibernation.
  226. acpi_use_timer_override [HW,ACPI]
  227. Use timer override. For some broken Nvidia NF5 boards
  228. that require a timer override, but don't have HPET
  229. acpi_enforce_resources= [ACPI]
  230. { strict | lax | no }
  231. Check for resource conflicts between native drivers
  232. and ACPI OperationRegions (SystemIO and SystemMemory
  233. only). IO ports and memory declared in ACPI might be
  234. used by the ACPI subsystem in arbitrary AML code and
  235. can interfere with legacy drivers.
  236. strict (default): access to resources claimed by ACPI
  237. is denied; legacy drivers trying to access reserved
  238. resources will fail to bind to device using them.
  239. lax: access to resources claimed by ACPI is allowed;
  240. legacy drivers trying to access reserved resources
  241. will bind successfully but a warning message is logged.
  242. no: ACPI OperationRegions are not marked as reserved,
  243. no further checks are performed.
  244. ad1848= [HW,OSS]
  245. Format: <io>,<irq>,<dma>,<dma2>,<type>
  246. add_efi_memmap [EFI; X86] Include EFI memory map in
  247. kernel's map of available physical RAM.
  248. advansys= [HW,SCSI]
  249. See header of drivers/scsi/advansys.c.
  250. advwdt= [HW,WDT] Advantech WDT
  251. Format: <iostart>,<iostop>
  252. aedsp16= [HW,OSS] Audio Excel DSP 16
  253. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  254. See also header of sound/oss/aedsp16.c.
  255. agp= [AGP]
  256. { off | try_unsupported }
  257. off: disable AGP support
  258. try_unsupported: try to drive unsupported chipsets
  259. (may crash computer or cause data corruption)
  260. aha152x= [HW,SCSI]
  261. See Documentation/scsi/aha152x.txt.
  262. aha1542= [HW,SCSI]
  263. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  264. aic7xxx= [HW,SCSI]
  265. See Documentation/scsi/aic7xxx.txt.
  266. aic79xx= [HW,SCSI]
  267. See Documentation/scsi/aic79xx.txt.
  268. amd_iommu= [HW,X86-84]
  269. Pass parameters to the AMD IOMMU driver in the system.
  270. Possible values are:
  271. isolate - enable device isolation (each device, as far
  272. as possible, will get its own protection
  273. domain) [default]
  274. share - put every device behind one IOMMU into the
  275. same protection domain
  276. fullflush - enable flushing of IO/TLB entries when
  277. they are unmapped. Otherwise they are
  278. flushed before they will be reused, which
  279. is a lot of faster
  280. amd_iommu_size= [HW,X86-64]
  281. Define the size of the aperture for the AMD IOMMU
  282. driver. Possible values are:
  283. '32M', '64M' (default), '128M', '256M', '512M', '1G'
  284. amijoy.map= [HW,JOY] Amiga joystick support
  285. Map of devices attached to JOY0DAT and JOY1DAT
  286. Format: <a>,<b>
  287. See also Documentation/kernel/input/joystick.txt
  288. analog.map= [HW,JOY] Analog joystick and gamepad support
  289. Specifies type or capabilities of an analog joystick
  290. connected to one of 16 gameports
  291. Format: <type1>,<type2>,..<type16>
  292. apc= [HW,SPARC]
  293. Power management functions (SPARCstation-4/5 + deriv.)
  294. Format: noidle
  295. Disable APC CPU standby support. SPARCstation-Fox does
  296. not play well with APC CPU idle - disable it if you have
  297. APC and your system crashes randomly.
  298. apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
  299. Change the output verbosity whilst booting
  300. Format: { quiet (default) | verbose | debug }
  301. Change the amount of debugging information output
  302. when initialising the APIC and IO-APIC components.
  303. apm= [APM] Advanced Power Management
  304. See header of arch/x86/kernel/apm_32.c.
  305. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  306. Format: <io>,<irq>,<nodeID>
  307. ataflop= [HW,M68k]
  308. atarimouse= [HW,MOUSE] Atari Mouse
  309. atascsi= [HW,SCSI] Atari SCSI
  310. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  311. EzKey and similar keyboards
  312. atkbd.reset= [HW] Reset keyboard during initialization
  313. atkbd.set= [HW] Select keyboard code set
  314. Format: <int> (2 = AT (default), 3 = PS/2)
  315. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  316. keyboards
  317. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  318. Format: <bool> (0 = real, 1 = synthetic (default))
  319. atkbd.softrepeat= [HW]
  320. Use software keyboard repeat
  321. autotest [IA64]
  322. baycom_epp= [HW,AX25]
  323. Format: <io>,<mode>
  324. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  325. Format: <io>,<mode>
  326. See header of drivers/net/hamradio/baycom_par.c.
  327. baycom_ser_fdx= [HW,AX25]
  328. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  329. Format: <io>,<irq>,<mode>[,<baud>]
  330. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  331. baycom_ser_hdx= [HW,AX25]
  332. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  333. Format: <io>,<irq>,<mode>
  334. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  335. boot_delay= Milliseconds to delay each printk during boot.
  336. Values larger than 10 seconds (10000) are changed to
  337. no delay (0).
  338. Format: integer
  339. bootmem_debug [KNL] Enable bootmem allocator debug messages.
  340. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  341. bttv.radio= Most important insmod options are available as
  342. kernel args too.
  343. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  344. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  345. BusLogic= [HW,SCSI]
  346. See drivers/scsi/BusLogic.c, comment before function
  347. BusLogic_ParseDriverOptions().
  348. c101= [NET] Moxa C101 synchronous serial card
  349. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  350. Sometimes CPU hardware bugs make them report the cache
  351. size incorrectly. The kernel will attempt work arounds
  352. to fix known problems, but for some CPUs it is not
  353. possible to determine what the correct size should be.
  354. This option provides an override for these situations.
  355. capability.disable=
  356. [SECURITY] Disable capabilities. This would normally
  357. be used only if an alternative security model is to be
  358. configured. Potentially dangerous and should only be
  359. used if you are entirely sure of the consequences.
  360. ccw_timeout_log [S390]
  361. See Documentation/s390/CommonIO for details.
  362. cgroup_disable= [KNL] Disable a particular controller
  363. Format: {name of the controller(s) to disable}
  364. {Currently supported controllers - "memory"}
  365. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  366. Format: { "0" | "1" }
  367. See security/selinux/Kconfig help text.
  368. 0 -- check protection applied by kernel (includes
  369. any implied execute protection).
  370. 1 -- check protection requested by application.
  371. Default value is set via a kernel config option.
  372. Value can be changed at runtime via
  373. /selinux/checkreqprot.
  374. cio_ignore= [S390]
  375. See Documentation/s390/CommonIO for details.
  376. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  377. [Deprecated]
  378. Forces specified clocksource (if available) to be used
  379. when calculating gettimeofday(). If specified
  380. clocksource is not available, it defaults to PIT.
  381. Format: { pit | tsc | cyclone | pmtmr }
  382. clocksource= [GENERIC_TIME] Override the default clocksource
  383. Format: <string>
  384. Override the default clocksource and use the clocksource
  385. with the name specified.
  386. Some clocksource names to choose from, depending on
  387. the platform:
  388. [all] jiffies (this is the base, fallback clocksource)
  389. [ACPI] acpi_pm
  390. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  391. pxa_timer,timer3,32k_counter,timer0_1
  392. [AVR32] avr32
  393. [X86-32] pit,hpet,tsc,vmi-timer;
  394. scx200_hrt on Geode; cyclone on IBM x440
  395. [MIPS] MIPS
  396. [PARISC] cr16
  397. [S390] tod
  398. [SH] SuperH
  399. [SPARC64] tick
  400. [X86-64] hpet,tsc
  401. clearcpuid=BITNUM [X86]
  402. Disable CPUID feature X for the kernel. See
  403. arch/x86/include/asm/cpufeature.h for the valid bit
  404. numbers. Note the Linux specific bits are not necessarily
  405. stable over kernel options, but the vendor specific
  406. ones should be.
  407. Also note that user programs calling CPUID directly
  408. or using the feature without checking anything
  409. will still see it. This just prevents it from
  410. being used by the kernel or shown in /proc/cpuinfo.
  411. Also note the kernel might malfunction if you disable
  412. some critical bits.
  413. code_bytes [X86] How many bytes of object code to print
  414. in an oops report.
  415. Range: 0 - 8192
  416. Default: 64
  417. com20020= [HW,NET] ARCnet - COM20020 chipset
  418. Format:
  419. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  420. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  421. Format: <io>[,<irq>]
  422. com90xx= [HW,NET]
  423. ARCnet - COM90xx chipset (memory-mapped buffers)
  424. Format: <io>[,<irq>[,<memstart>]]
  425. condev= [HW,S390] console device
  426. conmode=
  427. console= [KNL] Output console device and options.
  428. tty<n> Use the virtual console device <n>.
  429. ttyS<n>[,options]
  430. ttyUSB0[,options]
  431. Use the specified serial port. The options are of
  432. the form "bbbbpnf", where "bbbb" is the baud rate,
  433. "p" is parity ("n", "o", or "e"), "n" is number of
  434. bits, and "f" is flow control ("r" for RTS or
  435. omit it). Default is "9600n8".
  436. See Documentation/serial-console.txt for more
  437. information. See
  438. Documentation/networking/netconsole.txt for an
  439. alternative.
  440. uart[8250],io,<addr>[,options]
  441. uart[8250],mmio,<addr>[,options]
  442. Start an early, polled-mode console on the 8250/16550
  443. UART at the specified I/O port or MMIO address,
  444. switching to the matching ttyS device later. The
  445. options are the same as for ttyS, above.
  446. If the device connected to the port is not a TTY but a braille
  447. device, prepend "brl," before the device type, for instance
  448. console=brl,ttyS0
  449. For now, only VisioBraille is supported.
  450. coredump_filter=
  451. [KNL] Change the default value for
  452. /proc/<pid>/coredump_filter.
  453. See also Documentation/filesystems/proc.txt.
  454. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  455. Format:
  456. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  457. crashkernel=nn[KMG]@ss[KMG]
  458. [KNL] Reserve a chunk of physical memory to
  459. hold a kernel to switch to with kexec on panic.
  460. crashkernel=range1:size1[,range2:size2,...][@offset]
  461. [KNL] Same as above, but depends on the memory
  462. in the running system. The syntax of range is
  463. start-[end] where start and end are both
  464. a memory unit (amount[KMG]). See also
  465. Documentation/kdump/kdump.txt for a example.
  466. cs89x0_dma= [HW,NET]
  467. Format: <dma>
  468. cs89x0_media= [HW,NET]
  469. Format: { rj45 | aui | bnc }
  470. dasd= [HW,NET]
  471. See header of drivers/s390/block/dasd_devmap.c.
  472. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  473. (one device per port)
  474. Format: <port#>,<type>
  475. See also Documentation/input/joystick-parport.txt
  476. debug [KNL] Enable kernel debugging (events log level).
  477. debug_locks_verbose=
  478. [KNL] verbose self-tests
  479. Format=<0|1>
  480. Print debugging info while doing the locking API
  481. self-tests.
  482. We default to 0 (no extra messages), setting it to
  483. 1 will print _a lot_ more information - normally
  484. only useful to kernel developers.
  485. debug_objects [KNL] Enable object debugging
  486. no_debug_objects
  487. [KNL] Disable object debugging
  488. debugpat [X86] Enable PAT debugging
  489. decnet.addr= [HW,NET]
  490. Format: <area>[,<node>]
  491. See also Documentation/networking/decnet.txt.
  492. default_hugepagesz=
  493. [same as hugepagesz=] The size of the default
  494. HugeTLB page size. This is the size represented by
  495. the legacy /proc/ hugepages APIs, used for SHM, and
  496. default size when mounting hugetlbfs filesystems.
  497. Defaults to the default architecture's huge page size
  498. if not specified.
  499. dhash_entries= [KNL]
  500. Set number of hash buckets for dentry cache.
  501. digi= [HW,SERIAL]
  502. IO parameters + enable/disable command.
  503. digiepca= [HW,SERIAL]
  504. See drivers/char/README.epca and
  505. Documentation/serial/digiepca.txt.
  506. disable_mtrr_cleanup [X86]
  507. The kernel tries to adjust MTRR layout from continuous
  508. to discrete, to make X server driver able to add WB
  509. entry later. This parameter disables that.
  510. disable_mtrr_trim [X86, Intel and AMD only]
  511. By default the kernel will trim any uncacheable
  512. memory out of your available memory pool based on
  513. MTRR settings. This parameter disables that behavior,
  514. possibly causing your machine to run very slowly.
  515. disable_timer_pin_1 [X86]
  516. Disable PIN 1 of APIC timer
  517. Can be useful to work around chipset bugs.
  518. dmasound= [HW,OSS] Sound subsystem buffers
  519. dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
  520. this option disables the debugging code at boot.
  521. dma_debug_entries=<number>
  522. This option allows to tune the number of preallocated
  523. entries for DMA-API debugging code. One entry is
  524. required per DMA-API allocation. Use this if the
  525. DMA-API debugging code disables itself because the
  526. architectural default is too low.
  527. dscc4.setup= [NET]
  528. dtc3181e= [HW,SCSI]
  529. dynamic_printk Enables pr_debug()/dev_dbg() calls if
  530. CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
  531. These can also be switched on/off via
  532. <debugfs>/dynamic_printk/modules
  533. earlycon= [KNL] Output early console device and options.
  534. uart[8250],io,<addr>[,options]
  535. uart[8250],mmio,<addr>[,options]
  536. Start an early, polled-mode console on the 8250/16550
  537. UART at the specified I/O port or MMIO address.
  538. The options are the same as for ttyS, above.
  539. earlyprintk= [X86,SH,BLACKFIN]
  540. earlyprintk=vga
  541. earlyprintk=serial[,ttySn[,baudrate]]
  542. earlyprintk=dbgp
  543. Append ",keep" to not disable it when the real console
  544. takes over.
  545. Only vga or serial or usb debug port at a time.
  546. Currently only ttyS0 and ttyS1 are supported.
  547. Interaction with the standard serial driver is not
  548. very good.
  549. The VGA output is eventually overwritten by the real
  550. console.
  551. eata= [HW,SCSI]
  552. edd= [EDD]
  553. Format: {"off" | "on" | "skip[mbr]"}
  554. eisa_irq_edge= [PARISC,HW]
  555. See header of drivers/parisc/eisa.c.
  556. elanfreq= [X86-32]
  557. See comment before function elanfreq_setup() in
  558. arch/x86/kernel/cpu/cpufreq/elanfreq.c.
  559. elevator= [IOSCHED]
  560. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  561. See Documentation/block/as-iosched.txt and
  562. Documentation/block/deadline-iosched.txt for details.
  563. elfcorehdr= [IA64,PPC,SH,X86]
  564. Specifies physical address of start of kernel core
  565. image elf header. Generally kexec loader will
  566. pass this option to capture kernel.
  567. See Documentation/kdump/kdump.txt for details.
  568. enable_mtrr_cleanup [X86]
  569. The kernel tries to adjust MTRR layout from continuous
  570. to discrete, to make X server driver able to add WB
  571. entry later. This parameter enables that.
  572. enable_timer_pin_1 [X86]
  573. Enable PIN 1 of APIC timer
  574. Can be useful to work around chipset bugs
  575. (in particular on some ATI chipsets).
  576. The kernel tries to set a reasonable default.
  577. enforcing [SELINUX] Set initial enforcing status.
  578. Format: {"0" | "1"}
  579. See security/selinux/Kconfig help text.
  580. 0 -- permissive (log only, no denials).
  581. 1 -- enforcing (deny and log).
  582. Default value is 0.
  583. Value can be changed at runtime via /selinux/enforce.
  584. ether= [HW,NET] Ethernet cards parameters
  585. This option is obsoleted by the "netdev=" option, which
  586. has equivalent usage. See its documentation for details.
  587. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  588. Format: <io>[,<irq>]
  589. failslab=
  590. fail_page_alloc=
  591. fail_make_request=[KNL]
  592. General fault injection mechanism.
  593. Format: <interval>,<probability>,<space>,<times>
  594. See also /Documentation/fault-injection/.
  595. fd_mcs= [HW,SCSI]
  596. See header of drivers/scsi/fd_mcs.c.
  597. fdomain= [HW,SCSI]
  598. See header of drivers/scsi/fdomain.c.
  599. floppy= [HW]
  600. See Documentation/blockdev/floppy.txt.
  601. force_pal_cache_flush
  602. [IA-64] Avoid check_sal_cache_flush which may hang on
  603. buggy SAL_CACHE_FLUSH implementations. Using this
  604. parameter will force ia64_sal_cache_flush to call
  605. ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
  606. ftrace=[tracer]
  607. [ftrace] will set and start the specified tracer
  608. as early as possible in order to facilitate early
  609. boot debugging.
  610. ftrace_dump_on_oops
  611. [ftrace] will dump the trace buffers on oops.
  612. gamecon.map[2|3]=
  613. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  614. support via parallel port (up to 5 devices per port)
  615. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  616. See also Documentation/input/joystick-parport.txt
  617. gamma= [HW,DRM]
  618. gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
  619. Format: off | on
  620. default: on
  621. gdth= [HW,SCSI]
  622. See header of drivers/scsi/gdth.c.
  623. gpt [EFI] Forces disk with valid GPT signature but
  624. invalid Protective MBR to be treated as GPT.
  625. gvp11= [HW,SCSI]
  626. hashdist= [KNL,NUMA] Large hashes allocated during boot
  627. are distributed across NUMA nodes. Defaults on
  628. for 64bit NUMA, off otherwise.
  629. Format: 0 | 1 (for off | on)
  630. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  631. hd= [EIDE] (E)IDE hard drive subsystem geometry
  632. Format: <cyl>,<head>,<sect>
  633. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  634. size of <nn>. This works even on boxes that have no
  635. highmem otherwise. This also works to reduce highmem
  636. size on bigger boxes.
  637. highres= [KNL] Enable/disable high resolution timer mode.
  638. Valid parameters: "on", "off"
  639. Default: "on"
  640. hisax= [HW,ISDN]
  641. See Documentation/isdn/README.HiSax.
  642. hlt [BUGS=ARM,SH]
  643. hpet= [X86-32,HPET] option to control HPET usage
  644. Format: { enable (default) | disable | force |
  645. verbose }
  646. disable: disable HPET and use PIT instead
  647. force: allow force enabled of undocumented chips (ICH4,
  648. VIA, nVidia)
  649. verbose: show contents of HPET registers during setup
  650. hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
  651. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
  652. On x86-64 and powerpc, this option can be specified
  653. multiple times interleaved with hugepages= to reserve
  654. huge pages of different sizes. Valid pages sizes on
  655. x86-64 are 2M (when the CPU supports "pse") and 1G
  656. (when the CPU supports the "pdpe1gb" cpuinfo flag)
  657. Note that 1GB pages can only be allocated at boot time
  658. using hugepages= and not freed afterwards.
  659. hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
  660. terminal devices. Valid values: 0..8
  661. hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
  662. If specified, z/VM IUCV HVC accepts connections
  663. from listed z/VM user IDs only.
  664. i2c_bus= [HW] Override the default board specific I2C bus speed
  665. or register an additional I2C bus that is not
  666. registered from board initialization code.
  667. Format:
  668. <bus_id>,<clkrate>
  669. i8042.debug [HW] Toggle i8042 debug mode
  670. i8042.direct [HW] Put keyboard port into non-translated mode
  671. i8042.dumbkbd [HW] Pretend that controller can only read data from
  672. keyboard and cannot control its state
  673. (Don't attempt to blink the leds)
  674. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  675. i8042.nokbd [HW] Don't check/create keyboard port
  676. i8042.noloop [HW] Disable the AUX Loopback command while probing
  677. for the AUX port
  678. i8042.nomux [HW] Don't check presence of an active multiplexing
  679. controller
  680. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  681. controllers
  682. i8042.panicblink=
  683. [HW] Frequency with which keyboard LEDs should blink
  684. when kernel panics (default is 0.5 sec)
  685. i8042.reset [HW] Reset the controller during init and cleanup
  686. i8042.unlock [HW] Unlock (ignore) the keylock
  687. i810= [HW,DRM]
  688. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  689. indicates that the driver is running on unsupported
  690. hardware.
  691. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  692. does not match list of supported models.
  693. i8k.power_status
  694. [HW] Report power status in /proc/i8k
  695. (disabled by default)
  696. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  697. capability is set.
  698. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  699. See Documentation/mca.txt.
  700. icn= [HW,ISDN]
  701. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  702. ide-core.nodma= [HW] (E)IDE subsystem
  703. Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
  704. .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
  705. .chs .ignore_cable are additional options
  706. See Documentation/ide/ide.txt.
  707. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  708. See Documentation/ide/ide.txt.
  709. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
  710. Claim all unknown PCI IDE storage controllers.
  711. idle= [X86]
  712. Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
  713. Poll forces a polling idle loop that can slightly
  714. improve the performance of waking up a idle CPU, but
  715. will use a lot of power and make the system run hot.
  716. Not recommended.
  717. idle=mwait: On systems which support MONITOR/MWAIT but
  718. the kernel chose to not use it because it doesn't save
  719. as much power as a normal idle loop, use the
  720. MONITOR/MWAIT idle loop anyways. Performance should be
  721. the same as idle=poll.
  722. idle=halt: Halt is forced to be used for CPU idle.
  723. In such case C2/C3 won't be used again.
  724. idle=nomwait: Disable mwait for CPU C-states
  725. ignore_loglevel [KNL]
  726. Ignore loglevel setting - this will print /all/
  727. kernel messages to the console. Useful for debugging.
  728. ihash_entries= [KNL]
  729. Set number of hash buckets for inode cache.
  730. ima_audit= [IMA]
  731. Format: { "0" | "1" }
  732. 0 -- integrity auditing messages. (Default)
  733. 1 -- enable informational integrity auditing messages.
  734. ima_hash= [IMA]
  735. Formt: { "sha1" | "md5" }
  736. default: "sha1"
  737. ima_tcb [IMA]
  738. Load a policy which meets the needs of the Trusted
  739. Computing Base. This means IMA will measure all
  740. programs exec'd, files mmap'd for exec, and all files
  741. opened for read by uid=0.
  742. in2000= [HW,SCSI]
  743. See header of drivers/scsi/in2000.c.
  744. init= [KNL]
  745. Format: <full_path>
  746. Run specified binary instead of /sbin/init as init
  747. process.
  748. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  749. for working out where the kernel is dying during
  750. startup.
  751. initrd= [BOOT] Specify the location of the initial ramdisk
  752. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  753. Format: <irq>
  754. intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
  755. on
  756. Enable intel iommu driver.
  757. off
  758. Disable intel iommu driver.
  759. igfx_off [Default Off]
  760. By default, gfx is mapped as normal device. If a gfx
  761. device has a dedicated DMAR unit, the DMAR unit is
  762. bypassed by not enabling DMAR with this option. In
  763. this case, gfx device will use physical address for
  764. DMA.
  765. forcedac [x86_64]
  766. With this option iommu will not optimize to look
  767. for io virtual address below 32 bit forcing dual
  768. address cycle on pci bus for cards supporting greater
  769. than 32 bit addressing. The default is to look
  770. for translation below 32 bit and if not available
  771. then look in the higher range.
  772. strict [Default Off]
  773. With this option on every unmap_single operation will
  774. result in a hardware IOTLB flush operation as opposed
  775. to batching them for performance.
  776. inttest= [IA64]
  777. iomem= Disable strict checking of access to MMIO memory
  778. strict regions from userspace.
  779. relaxed
  780. iommu= [x86]
  781. off
  782. force
  783. noforce
  784. biomerge
  785. panic
  786. nopanic
  787. merge
  788. nomerge
  789. forcesac
  790. soft
  791. io7= [HW] IO7 for Marvel based alpha systems
  792. See comment before marvel_specify_io7 in
  793. arch/alpha/kernel/core_marvel.c.
  794. io_delay= [X86] I/O delay method
  795. 0x80
  796. Standard port 0x80 based delay
  797. 0xed
  798. Alternate port 0xed based delay (needed on some systems)
  799. udelay
  800. Simple two microseconds delay
  801. none
  802. No delay
  803. ip= [IP_PNP]
  804. See Documentation/filesystems/nfsroot.txt.
  805. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  806. See comment before ip2_setup() in
  807. drivers/char/ip2/ip2base.c.
  808. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  809. See header of drivers/scsi/ips.c.
  810. irqfixup [HW]
  811. When an interrupt is not handled search all handlers
  812. for it. Intended to get systems with badly broken
  813. firmware running.
  814. irqpoll [HW]
  815. When an interrupt is not handled search all handlers
  816. for it. Also check all handlers each timer
  817. interrupt. Intended to get systems with badly broken
  818. firmware running.
  819. isapnp= [ISAPNP]
  820. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  821. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  822. Format:
  823. <cpu number>,...,<cpu number>
  824. or
  825. <cpu number>-<cpu number>
  826. (must be a positive range in ascending order)
  827. or a mixture
  828. <cpu number>,...,<cpu number>-<cpu number>
  829. This option can be used to specify one or more CPUs
  830. to isolate from the general SMP balancing and scheduling
  831. algorithms. You can move a process onto or off an
  832. "isolated" CPU via the CPU affinity syscalls or cpuset.
  833. <cpu number> begins at 0 and the maximum value is
  834. "number of CPUs in system - 1".
  835. This option is the preferred way to isolate CPUs. The
  836. alternative -- manually setting the CPU mask of all
  837. tasks in the system -- can cause problems and
  838. suboptimal load balancer performance.
  839. iucv= [HW,NET]
  840. js= [HW,JOY] Analog joystick
  841. See Documentation/input/joystick.txt.
  842. keepinitrd [HW,ARM]
  843. kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
  844. specifies the amount of memory usable by the kernel
  845. for non-movable allocations. The requested amount is
  846. spread evenly throughout all nodes in the system. The
  847. remaining memory in each node is used for Movable
  848. pages. In the event, a node is too small to have both
  849. kernelcore and Movable pages, kernelcore pages will
  850. take priority and other nodes will have a larger number
  851. of kernelcore pages. The Movable zone is used for the
  852. allocation of pages that may be reclaimed or moved
  853. by the page migration subsystem. This means that
  854. HugeTLB pages may not be allocated from this zone.
  855. Note that allocations like PTEs-from-HighMem still
  856. use the HighMem zone if it exists, and the Normal
  857. zone if it does not.
  858. kmemtrace.enable= [KNL,KMEMTRACE] Format: { yes | no }
  859. Controls whether kmemtrace is enabled
  860. at boot-time.
  861. kmemtrace.subbufs=n [KNL,KMEMTRACE] Overrides the number of
  862. subbufs kmemtrace's relay channel has. Set this
  863. higher than default (KMEMTRACE_N_SUBBUFS in code) if
  864. you experience buffer overruns.
  865. kgdboc= [HW] kgdb over consoles.
  866. Requires a tty driver that supports console polling.
  867. (only serial suported for now)
  868. Format: <serial_device>[,baud]
  869. kmac= [MIPS] korina ethernet MAC address.
  870. Configure the RouterBoard 532 series on-chip
  871. Ethernet adapter MAC address.
  872. kstack=N [X86] Print N words from the kernel stack
  873. in oops dumps.
  874. l2cr= [PPC]
  875. l3cr= [PPC]
  876. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  877. disabled it.
  878. lapic_timer_c2_ok [X86,APIC] trust the local apic timer
  879. in C2 power state.
  880. libata.dma= [LIBATA] DMA control
  881. libata.dma=0 Disable all PATA and SATA DMA
  882. libata.dma=1 PATA and SATA Disk DMA only
  883. libata.dma=2 ATAPI (CDROM) DMA only
  884. libata.dma=4 Compact Flash DMA only
  885. Combinations also work, so libata.dma=3 enables DMA
  886. for disks and CDROMs, but not CFs.
  887. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  888. when set.
  889. Format: <int>
  890. libata.force= [LIBATA] Force configurations. The format is comma
  891. separated list of "[ID:]VAL" where ID is
  892. PORT[:DEVICE]. PORT and DEVICE are decimal numbers
  893. matching port, link or device. Basically, it matches
  894. the ATA ID string printed on console by libata. If
  895. the whole ID part is omitted, the last PORT and DEVICE
  896. values are used. If ID hasn't been specified yet, the
  897. configuration applies to all ports, links and devices.
  898. If only DEVICE is omitted, the parameter applies to
  899. the port and all links and devices behind it. DEVICE
  900. number of 0 either selects the first device or the
  901. first fan-out link behind PMP device. It does not
  902. select the host link. DEVICE number of 15 selects the
  903. host link and device attached to it.
  904. The VAL specifies the configuration to force. As long
  905. as there's no ambiguity shortcut notation is allowed.
  906. For example, both 1.5 and 1.5G would work for 1.5Gbps.
  907. The following configurations can be forced.
  908. * Cable type: 40c, 80c, short40c, unk, ign or sata.
  909. Any ID with matching PORT is used.
  910. * SATA link speed limit: 1.5Gbps or 3.0Gbps.
  911. * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
  912. udma[/][16,25,33,44,66,100,133] notation is also
  913. allowed.
  914. * [no]ncq: Turn on or off NCQ.
  915. * nohrst, nosrst, norst: suppress hard, soft
  916. and both resets.
  917. If there are multiple matching configurations changing
  918. the same attribute, the last one is used.
  919. lmb=debug [KNL] Enable lmb debug messages.
  920. load_ramdisk= [RAM] List of ramdisks to load from floppy
  921. See Documentation/blockdev/ramdisk.txt.
  922. lockd.nlm_grace_period=P [NFS] Assign grace period.
  923. Format: <integer>
  924. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  925. Format: <integer>
  926. lockd.nlm_timeout=T [NFS] Assign timeout value.
  927. Format: <integer>
  928. lockd.nlm_udpport=M [NFS] Assign UDP port.
  929. Format: <integer>
  930. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  931. Format: <irq>
  932. loglevel= All Kernel Messages with a loglevel smaller than the
  933. console loglevel will be printed to the console. It can
  934. also be changed with klogd or other programs. The
  935. loglevels are defined as follows:
  936. 0 (KERN_EMERG) system is unusable
  937. 1 (KERN_ALERT) action must be taken immediately
  938. 2 (KERN_CRIT) critical conditions
  939. 3 (KERN_ERR) error conditions
  940. 4 (KERN_WARNING) warning conditions
  941. 5 (KERN_NOTICE) normal but significant condition
  942. 6 (KERN_INFO) informational
  943. 7 (KERN_DEBUG) debug-level messages
  944. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  945. Format: { n | nk | nM }
  946. n must be a power of two. The default size
  947. is set in the kernel config file.
  948. logo.nologo [FB] Disables display of the built-in Linux logo.
  949. This may be used to provide more screen space for
  950. kernel log messages and is useful when debugging
  951. kernel boot problems.
  952. lp=0 [LP] Specify parallel ports to use, e.g,
  953. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  954. lp=reset first parallel port). 'lp=0' disables the
  955. lp=auto printer driver. 'lp=reset' (which can be
  956. specified in addition to the ports) causes
  957. attached printers to be reset. Using
  958. lp=port1,port2,... specifies the parallel ports
  959. to associate lp devices with, starting with
  960. lp0. A port specification may be 'none' to skip
  961. that lp device, or a parport name such as
  962. 'parport0'. Specifying 'lp=auto' instead of a
  963. port specification list means that device IDs
  964. from each port should be examined, to see if
  965. an IEEE 1284-compliant printer is attached; if
  966. so, the driver will manage that printer.
  967. See also header of drivers/char/lp.c.
  968. lpj=n [KNL]
  969. Sets loops_per_jiffy to given constant, thus avoiding
  970. time-consuming boot-time autodetection (up to 250 ms per
  971. CPU). 0 enables autodetection (default). To determine
  972. the correct value for your kernel, boot with normal
  973. autodetection and see what value is printed. Note that
  974. on SMP systems the preset will be applied to all CPUs,
  975. which is likely to cause problems if your CPUs need
  976. significantly divergent settings. An incorrect value
  977. will cause delays in the kernel to be wrong, leading to
  978. unpredictable I/O errors and other breakage. Although
  979. unlikely, in the extreme case this might damage your
  980. hardware.
  981. ltpc= [NET]
  982. Format: <io>,<irq>,<dma>
  983. mac5380= [HW,SCSI] Format:
  984. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  985. machvec= [IA64] Force the use of a particular machine-vector
  986. (machvec) in a generic kernel.
  987. Example: machvec=hpzx1_swiotlb
  988. max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
  989. than or equal to this physical address is ignored.
  990. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  991. should make use of. maxcpus=n : n >= 0 limits the
  992. kernel to using 'n' processors. n=0 is a special case,
  993. it is equivalent to "nosmp", which also disables
  994. the IO APIC.
  995. max_loop= [LOOP] Maximum number of loopback devices that can
  996. be mounted
  997. Format: <1-256>
  998. max_luns= [SCSI] Maximum number of LUNs to probe.
  999. Should be between 1 and 2^32-1.
  1000. max_report_luns=
  1001. [SCSI] Maximum number of LUNs received.
  1002. Should be between 1 and 16384.
  1003. mcatest= [IA-64]
  1004. mce [X86-32] Machine Check Exception
  1005. mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
  1006. md= [HW] RAID subsystems devices and level
  1007. See Documentation/md.txt.
  1008. mdacon= [MDA]
  1009. Format: <first>,<last>
  1010. Specifies range of consoles to be captured by the MDA.
  1011. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  1012. Amount of memory to be used when the kernel is not able
  1013. to see the whole system memory or for test.
  1014. [X86-32] Use together with memmap= to avoid physical
  1015. address space collisions. Without memmap= PCI devices
  1016. could be placed at addresses belonging to unused RAM.
  1017. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  1018. memory.
  1019. memchunk=nn[KMG]
  1020. [KNL,SH] Allow user to override the default size for
  1021. per-device physically contiguous DMA buffers.
  1022. memmap=exactmap [KNL,X86] Enable setting of an exact
  1023. E820 memory map, as specified by the user.
  1024. Such memmap=exactmap lines can be constructed based on
  1025. BIOS output or other requirements. See the memmap=nn@ss
  1026. option description.
  1027. memmap=nn[KMG]@ss[KMG]
  1028. [KNL] Force usage of a specific region of memory
  1029. Region of memory to be used, from ss to ss+nn.
  1030. memmap=nn[KMG]#ss[KMG]
  1031. [KNL,ACPI] Mark specific memory as ACPI data.
  1032. Region of memory to be used, from ss to ss+nn.
  1033. memmap=nn[KMG]$ss[KMG]
  1034. [KNL,ACPI] Mark specific memory as reserved.
  1035. Region of memory to be used, from ss to ss+nn.
  1036. Example: Exclude memory from 0x18690000-0x1869ffff
  1037. memmap=64K$0x18690000
  1038. or
  1039. memmap=0x10000$0x18690000
  1040. memory_corruption_check=0/1 [X86]
  1041. Some BIOSes seem to corrupt the first 64k of
  1042. memory when doing things like suspend/resume.
  1043. Setting this option will scan the memory
  1044. looking for corruption. Enabling this will
  1045. both detect corruption and prevent the kernel
  1046. from using the memory being corrupted.
  1047. However, its intended as a diagnostic tool; if
  1048. repeatable BIOS-originated corruption always
  1049. affects the same memory, you can use memmap=
  1050. to prevent the kernel from using that memory.
  1051. memory_corruption_check_size=size [X86]
  1052. By default it checks for corruption in the low
  1053. 64k, making this memory unavailable for normal
  1054. use. Use this parameter to scan for
  1055. corruption in more or less memory.
  1056. memory_corruption_check_period=seconds [X86]
  1057. By default it checks for corruption every 60
  1058. seconds. Use this parameter to check at some
  1059. other rate. 0 disables periodic checking.
  1060. memtest= [KNL,X86] Enable memtest
  1061. Format: <integer>
  1062. default : 0 <disable>
  1063. Specifies the number of memtest passes to be
  1064. performed. Each pass selects another test
  1065. pattern from a given set of patterns. Memtest
  1066. fills the memory with this pattern, validates
  1067. memory contents and reserves bad memory
  1068. regions that are detected.
  1069. meye.*= [HW] Set MotionEye Camera parameters
  1070. See Documentation/video4linux/meye.txt.
  1071. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  1072. Multi-Function General Purpose Timers on AMD Geode
  1073. platforms.
  1074. mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
  1075. the BIOS has incorrectly applied a workaround. TinyBIOS
  1076. version 0.98 is known to be affected, 0.99 fixes the
  1077. problem by letting the user disable the workaround.
  1078. mga= [HW,DRM]
  1079. min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
  1080. physical address is ignored.
  1081. mminit_loglevel=
  1082. [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
  1083. parameter allows control of the logging verbosity for
  1084. the additional memory initialisation checks. A value
  1085. of 0 disables mminit logging and a level of 4 will
  1086. log everything. Information is printed at KERN_DEBUG
  1087. so loglevel=8 may also need to be specified.
  1088. mousedev.tap_time=
  1089. [MOUSE] Maximum time between finger touching and
  1090. leaving touchpad surface for touch to be considered
  1091. a tap and be reported as a left button click (for
  1092. touchpads working in absolute mode only).
  1093. Format: <msecs>
  1094. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  1095. reporting absolute coordinates, such as tablets
  1096. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  1097. reporting absolute coordinates, such as tablets
  1098. movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
  1099. is similar to kernelcore except it specifies the
  1100. amount of memory used for migratable allocations.
  1101. If both kernelcore and movablecore is specified,
  1102. then kernelcore will be at *least* the specified
  1103. value but may be more. If movablecore on its own
  1104. is specified, the administrator must be careful
  1105. that the amount of memory usable for all allocations
  1106. is not too small.
  1107. mpu401= [HW,OSS]
  1108. Format: <io>,<irq>
  1109. MTD_Partition= [MTD]
  1110. Format: <name>,<region-number>,<size>,<offset>
  1111. MTD_Region= [MTD] Format:
  1112. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  1113. mtdparts= [MTD]
  1114. See drivers/mtd/cmdlinepart.c.
  1115. mtdset= [ARM]
  1116. ARM/S3C2412 JIVE boot control
  1117. See arch/arm/mach-s3c2412/mach-jive.c
  1118. mtouchusb.raw_coordinates=
  1119. [HW] Make the MicroTouch USB driver use raw coordinates
  1120. ('y', default) or cooked coordinates ('n')
  1121. mtrr_chunk_size=nn[KMG] [X86]
  1122. used for mtrr cleanup. It is largest continous chunk
  1123. that could hold holes aka. UC entries.
  1124. mtrr_gran_size=nn[KMG] [X86]
  1125. Used for mtrr cleanup. It is granularity of mtrr block.
  1126. Default is 1.
  1127. Large value could prevent small alignment from
  1128. using up MTRRs.
  1129. mtrr_spare_reg_nr=n [X86]
  1130. Format: <integer>
  1131. Range: 0,7 : spare reg number
  1132. Default : 1
  1133. Used for mtrr cleanup. It is spare mtrr entries number.
  1134. Set to 2 or more if your graphical card needs more.
  1135. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  1136. NCR_D700= [HW,SCSI]
  1137. See header of drivers/scsi/NCR_D700.c.
  1138. ncr5380= [HW,SCSI]
  1139. ncr53c400= [HW,SCSI]
  1140. ncr53c400a= [HW,SCSI]
  1141. ncr53c406a= [HW,SCSI]
  1142. ncr53c8xx= [HW,SCSI]
  1143. netdev= [NET] Network devices parameters
  1144. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  1145. Note that mem_start is often overloaded to mean
  1146. something different and driver-specific.
  1147. This usage is only documented in each driver source
  1148. file if at all.
  1149. nf_conntrack.acct=
  1150. [NETFILTER] Enable connection tracking flow accounting
  1151. 0 to disable accounting
  1152. 1 to enable accounting
  1153. Default value depends on CONFIG_NF_CT_ACCT that is
  1154. going to be removed in 2.6.29.
  1155. nfsaddrs= [NFS]
  1156. See Documentation/filesystems/nfsroot.txt.
  1157. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  1158. See Documentation/filesystems/nfsroot.txt.
  1159. nfs.callback_tcpport=
  1160. [NFS] set the TCP port on which the NFSv4 callback
  1161. channel should listen.
  1162. nfs.idmap_cache_timeout=
  1163. [NFS] set the maximum lifetime for idmapper cache
  1164. entries.
  1165. nfs.enable_ino64=
  1166. [NFS] enable 64-bit inode numbers.
  1167. If zero, the NFS client will fake up a 32-bit inode
  1168. number for the readdir() and stat() syscalls instead
  1169. of returning the full 64-bit number.
  1170. The default is to return 64-bit inode numbers.
  1171. nmi_debug= [KNL,AVR32] Specify one or more actions to take
  1172. when a NMI is triggered.
  1173. Format: [state][,regs][,debounce][,die]
  1174. nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
  1175. Format: [panic,][num]
  1176. Valid num: 0,1,2
  1177. 0 - turn nmi_watchdog off
  1178. 1 - use the IO-APIC timer for the NMI watchdog
  1179. 2 - use the local APIC for the NMI watchdog using
  1180. a performance counter. Note: This will use one
  1181. performance counter and the local APIC's performance
  1182. vector.
  1183. When panic is specified, panic when an NMI watchdog
  1184. timeout occurs.
  1185. This is useful when you use a panic=... timeout and
  1186. need the box quickly up again.
  1187. Instead of 1 and 2 it is possible to use the following
  1188. symbolic names: lapic and ioapic
  1189. Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
  1190. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  1191. emulation library even if a 387 maths coprocessor
  1192. is present.
  1193. no_console_suspend
  1194. [HW] Never suspend the console
  1195. Disable suspending of consoles during suspend and
  1196. hibernate operations. Once disabled, debugging
  1197. messages can reach various consoles while the rest
  1198. of the system is being put to sleep (ie, while
  1199. debugging driver suspend/resume hooks). This may
  1200. not work reliably with all consoles, but is known
  1201. to work with serial and VGA consoles.
  1202. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  1203. caches in the slab allocator. Saves per-node memory,
  1204. but will impact performance.
  1205. noalign [KNL,ARM]
  1206. noapic [SMP,APIC] Tells the kernel to not make use of any
  1207. IOAPICs that may be present in the system.
  1208. nobats [PPC] Do not use BATs for mapping kernel lowmem
  1209. on "Classic" PPC cores.
  1210. nocache [ARM]
  1211. noclflush [BUGS=X86] Don't use the CLFLUSH instruction
  1212. nodelayacct [KNL] Disable per-task delay accounting
  1213. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  1214. nodsp [SH] Disable hardware DSP at boot time.
  1215. noefi [X86] Disable EFI runtime services support.
  1216. noexec [IA-64]
  1217. noexec [X86]
  1218. On X86-32 available only on PAE configured kernels.
  1219. noexec=on: enable non-executable mappings (default)
  1220. noexec=off: disable non-executable mappings
  1221. noexec32 [X86-64]
  1222. This affects only 32-bit executables.
  1223. noexec32=on: enable non-executable mappings (default)
  1224. read doesn't imply executable mappings
  1225. noexec32=off: disable non-executable mappings
  1226. read implies executable mappings
  1227. nofpu [SH] Disable hardware FPU at boot time.
  1228. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  1229. register save and restore. The kernel will only save
  1230. legacy floating-point registers on task switch.
  1231. nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
  1232. wfi(ARM) instruction doesn't work correctly and not to
  1233. use it. This is also useful when using JTAG debugger.
  1234. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  1235. instruction doesn't work correctly and not to
  1236. use it.
  1237. no_file_caps Tells the kernel not to honor file capabilities. The
  1238. only way then for a file to be executed with privilege
  1239. is to be setuid root or executed by root.
  1240. nohalt [IA-64] Tells the kernel not to use the power saving
  1241. function PAL_HALT_LIGHT when idle. This increases
  1242. power-consumption. On the positive side, it reduces
  1243. interrupt wake-up latency, which may improve performance
  1244. in certain environments such as networked servers or
  1245. real-time systems.
  1246. nohz= [KNL] Boottime enable/disable dynamic ticks
  1247. Valid arguments: on, off
  1248. Default: on
  1249. noiotrap [SH] Disables trapped I/O port accesses.
  1250. noirqdebug [X86-32] Disables the code which attempts to detect and
  1251. disable unhandled interrupt sources.
  1252. no_timer_check [X86,APIC] Disables the code which tests for
  1253. broken timer IRQ sources.
  1254. noisapnp [ISAPNP] Disables ISA PnP code.
  1255. noinitrd [RAM] Tells the kernel not to load any configured
  1256. initial RAM disk.
  1257. nointroute [IA-64]
  1258. nojitter [IA64] Disables jitter checking for ITC timers.
  1259. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  1260. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  1261. noltlbs [PPC] Do not use large page/tlb entries for kernel
  1262. lowmem mapping on PPC40x.
  1263. nomca [IA-64] Disable machine check abort handling
  1264. nomce [X86-32] Machine Check Exception
  1265. nomfgpt [X86-32] Disable Multi-Function General Purpose
  1266. Timer usage (for AMD Geode machines).
  1267. norandmaps Don't use address space randomization. Equivalent to
  1268. echo 0 > /proc/sys/kernel/randomize_va_space
  1269. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  1270. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  1271. with UP alternatives
  1272. noresidual [PPC] Don't use residual data on PReP machines.
  1273. noresume [SWSUSP] Disables resume and restores original swap
  1274. space.
  1275. no-scroll [VGA] Disables scrollback.
  1276. This is required for the Braillex ib80-piezo Braille
  1277. reader made by F.H. Papenmeier (Germany).
  1278. nosbagart [IA-64]
  1279. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  1280. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  1281. and disable the IO APIC. legacy for "maxcpus=0".
  1282. nosoftlockup [KNL] Disable the soft-lockup detector.
  1283. noswapaccount [KNL] Disable accounting of swap in memory resource
  1284. controller. (See Documentation/cgroups/memory.txt)
  1285. nosync [HW,M68K] Disables sync negotiation for all devices.
  1286. notsc [BUGS=X86-32] Disable Time Stamp Counter
  1287. nousb [USB] Disable the USB subsystem
  1288. nowb [ARM]
  1289. nox2apic [X86-64,APIC] Do not enable x2APIC mode.
  1290. nptcg= [IA64] Override max number of concurrent global TLB
  1291. purges which is reported from either PAL_VM_SUMMARY or
  1292. SAL PALO.
  1293. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  1294. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  1295. one of ['zone', 'node', 'default'] can be specified
  1296. This can be set from sysctl after boot.
  1297. See Documentation/sysctl/vm.txt for details.
  1298. ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
  1299. See Documentation/debugging-via-ohci1394.txt for more
  1300. info.
  1301. olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
  1302. Rather than timing out after 20 ms if an EC
  1303. command is not properly ACKed, override the length
  1304. of the timeout. We have interrupts disabled while
  1305. waiting for the ACK, so if this is set too high
  1306. interrupts *may* be lost!
  1307. opl3= [HW,OSS]
  1308. Format: <io>
  1309. oprofile.timer= [HW]
  1310. Use timer interrupt instead of performance counters
  1311. osst= [HW,SCSI] SCSI Tape Driver
  1312. Format: <buffer_size>,<write_threshold>
  1313. See also Documentation/scsi/st.txt.
  1314. panic= [KNL] Kernel behaviour on panic
  1315. Format: <timeout>
  1316. parkbd.port= [HW] Parallel port number the keyboard adapter is
  1317. connected to, default is 0.
  1318. Format: <parport#>
  1319. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  1320. 0 for XT, 1 for AT (default is AT).
  1321. Format: <mode>
  1322. parport= [HW,PPT] Specify parallel ports. 0 disables.
  1323. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  1324. Use 'auto' to force the driver to use any
  1325. IRQ/DMA settings detected (the default is to
  1326. ignore detected IRQ/DMA settings because of
  1327. possible conflicts). You can specify the base
  1328. address, IRQ, and DMA settings; IRQ and DMA
  1329. should be numbers, or 'auto' (for using detected
  1330. settings on that particular port), or 'nofifo'
  1331. (to avoid using a FIFO even if it is detected).
  1332. Parallel ports are assigned in the order they
  1333. are specified on the command line, starting
  1334. with parport0.
  1335. parport_init_mode= [HW,PPT]
  1336. Configure VIA parallel port to operate in
  1337. a specific mode. This is necessary on Pegasos
  1338. computer where firmware has no options for setting
  1339. up parallel port mode and sets it to spp.
  1340. Currently this function knows 686a and 8231 chips.
  1341. Format: [spp|ps2|epp|ecp|ecpepp]
  1342. pas2= [HW,OSS] Format:
  1343. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  1344. pas16= [HW,SCSI]
  1345. See header of drivers/scsi/pas16.c.
  1346. pause_on_oops=
  1347. Halt all CPUs after the first oops has been printed for
  1348. the specified number of seconds. This is to be used if
  1349. your oopses keep scrolling off the screen.
  1350. pcbit= [HW,ISDN]
  1351. pcd. [PARIDE]
  1352. See header of drivers/block/paride/pcd.c.
  1353. See also Documentation/blockdev/paride.txt.
  1354. pci=option[,option...] [PCI] various PCI subsystem options:
  1355. earlydump [X86] dump PCI config space before the kernel
  1356. changes anything
  1357. off [X86] don't probe for the PCI bus
  1358. bios [X86-32] force use of PCI BIOS, don't access
  1359. the hardware directly. Use this if your machine
  1360. has a non-standard PCI host bridge.
  1361. nobios [X86-32] disallow use of PCI BIOS, only direct
  1362. hardware access methods are allowed. Use this
  1363. if you experience crashes upon bootup and you
  1364. suspect they are caused by the BIOS.
  1365. conf1 [X86] Force use of PCI Configuration
  1366. Mechanism 1.
  1367. conf2 [X86] Force use of PCI Configuration
  1368. Mechanism 2.
  1369. noaer [PCIE] If the PCIEAER kernel config parameter is
  1370. enabled, this kernel boot option can be used to
  1371. disable the use of PCIE advanced error reporting.
  1372. nodomains [PCI] Disable support for multiple PCI
  1373. root domains (aka PCI segments, in ACPI-speak).
  1374. nommconf [X86] Disable use of MMCONFIG for PCI
  1375. Configuration
  1376. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1377. enabled, this kernel boot option can be used to
  1378. disable the use of MSI interrupts system-wide.
  1379. noioapicquirk [APIC] Disable all boot interrupt quirks.
  1380. Safety option to keep boot IRQs enabled. This
  1381. should never be necessary.
  1382. ioapicreroute [APIC] Enable rerouting of boot IRQs to the
  1383. primary IO-APIC for bridges that cannot disable
  1384. boot IRQs. This fixes a source of spurious IRQs
  1385. when the system masks IRQs.
  1386. noioapicreroute [APIC] Disable workaround that uses the
  1387. boot IRQ equivalent of an IRQ that connects to
  1388. a chipset where boot IRQs cannot be disabled.
  1389. The opposite of ioapicreroute.
  1390. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1391. routing table. These calls are known to be buggy
  1392. on several machines and they hang the machine
  1393. when used, but on other computers it's the only
  1394. way to get the interrupt routing table. Try
  1395. this option if the kernel is unable to allocate
  1396. IRQs or discover secondary PCI buses on your
  1397. motherboard.
  1398. rom [X86] Assign address space to expansion ROMs.
  1399. Use with caution as certain devices share
  1400. address decoders between ROMs and other
  1401. resources.
  1402. norom [X86] Do not assign address space to
  1403. expansion ROMs that do not already have
  1404. BIOS assigned address ranges.
  1405. irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
  1406. assigned automatically to PCI devices. You can
  1407. make the kernel exclude IRQs of your ISA cards
  1408. this way.
  1409. pirqaddr=0xAAAAA [X86] Specify the physical address
  1410. of the PIRQ table (normally generated
  1411. by the BIOS) if it is outside the
  1412. F0000h-100000h range.
  1413. lastbus=N [X86] Scan all buses thru bus #N. Can be
  1414. useful if the kernel is unable to find your
  1415. secondary buses and you want to tell it
  1416. explicitly which ones they are.
  1417. assign-busses [X86] Always assign all PCI bus
  1418. numbers ourselves, overriding
  1419. whatever the firmware may have done.
  1420. usepirqmask [X86] Honor the possible IRQ mask stored
  1421. in the BIOS $PIR table. This is needed on
  1422. some systems with broken BIOSes, notably
  1423. some HP Pavilion N5400 and Omnibook XE3
  1424. notebooks. This will have no effect if ACPI
  1425. IRQ routing is enabled.
  1426. noacpi [X86] Do not use ACPI for IRQ routing
  1427. or for PCI scanning.
  1428. use_crs [X86] Use _CRS for PCI resource
  1429. allocation.
  1430. routeirq Do IRQ routing for all PCI devices.
  1431. This is normally done in pci_enable_device(),
  1432. so this option is a temporary workaround
  1433. for broken drivers that don't call it.
  1434. skip_isa_align [X86] do not align io start addr, so can
  1435. handle more pci cards
  1436. firmware [ARM] Do not re-enumerate the bus but instead
  1437. just use the configuration from the
  1438. bootloader. This is currently used on
  1439. IXP2000 systems where the bus has to be
  1440. configured a certain way for adjunct CPUs.
  1441. noearly [X86] Don't do any early type 1 scanning.
  1442. This might help on some broken boards which
  1443. machine check when some devices' config space
  1444. is read. But various workarounds are disabled
  1445. and some IOMMU drivers will not work.
  1446. bfsort Sort PCI devices into breadth-first order.
  1447. This sorting is done to get a device
  1448. order compatible with older (<= 2.4) kernels.
  1449. nobfsort Don't sort PCI devices into breadth-first order.
  1450. cbiosize=nn[KMG] The fixed amount of bus space which is
  1451. reserved for the CardBus bridge's IO window.
  1452. The default value is 256 bytes.
  1453. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1454. reserved for the CardBus bridge's memory
  1455. window. The default value is 64 megabytes.
  1456. resource_alignment=
  1457. Format:
  1458. [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
  1459. Specifies alignment and device to reassign
  1460. aligned memory resources.
  1461. If <order of align> is not specified,
  1462. PAGE_SIZE is used as alignment.
  1463. PCI-PCI bridge can be specified, if resource
  1464. windows need to be expanded.
  1465. pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
  1466. Management.
  1467. off Disable ASPM.
  1468. force Enable ASPM even on devices that claim not to support it.
  1469. WARNING: Forcing ASPM on may cause system lockups.
  1470. pcmv= [HW,PCMCIA] BadgePAD 4
  1471. pd. [PARIDE]
  1472. See Documentation/blockdev/paride.txt.
  1473. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1474. boot time.
  1475. Format: { 0 | 1 }
  1476. See arch/parisc/kernel/pdc_chassis.c
  1477. pf. [PARIDE]
  1478. See Documentation/blockdev/paride.txt.
  1479. pg. [PARIDE]
  1480. See Documentation/blockdev/paride.txt.
  1481. pirq= [SMP,APIC] Manual mp-table setup
  1482. See Documentation/x86/i386/IO-APIC.txt.
  1483. plip= [PPT,NET] Parallel port network link
  1484. Format: { parport<nr> | timid | 0 }
  1485. See also Documentation/parport.txt.
  1486. pmtmr= [X86] Manual setup of pmtmr I/O Port.
  1487. Override pmtimer IOPort with a hex value.
  1488. e.g. pmtmr=0x508
  1489. pnp.debug [PNP]
  1490. Enable PNP debug messages. This depends on the
  1491. CONFIG_PNP_DEBUG_MESSAGES option.
  1492. pnpacpi= [ACPI]
  1493. { off }
  1494. pnpbios= [ISAPNP]
  1495. { on | off | curr | res | no-curr | no-res }
  1496. pnp_reserve_irq=
  1497. [ISAPNP] Exclude IRQs for the autoconfiguration
  1498. pnp_reserve_dma=
  1499. [ISAPNP] Exclude DMAs for the autoconfiguration
  1500. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1501. Ranges are in pairs (I/O port base and size).
  1502. pnp_reserve_mem=
  1503. [ISAPNP] Exclude memory regions for the
  1504. autoconfiguration.
  1505. Ranges are in pairs (memory base and size).
  1506. ports= [IP_VS_FTP] IPVS ftp helper module
  1507. Default is 21.
  1508. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  1509. may be specified.
  1510. Format: <port>,<port>....
  1511. print-fatal-signals=
  1512. [KNL] debug: print fatal signals
  1513. print-fatal-signals=1: print segfault info to
  1514. the kernel console.
  1515. default: off.
  1516. printk.time= Show timing data prefixed to each printk message line
  1517. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1518. processor.max_cstate= [HW,ACPI]
  1519. Limit processor to maximum C-state
  1520. max_cstate=9 overrides any DMI blacklist limit.
  1521. processor.nocst [HW,ACPI]
  1522. Ignore the _CST method to determine C-states,
  1523. instead using the legacy FADT method
  1524. profile= [KNL] Enable kernel profiling via /proc/profile
  1525. Format: [schedule,]<number>
  1526. Param: "schedule" - profile schedule points.
  1527. Param: <number> - step/bucket size as a power of 2 for
  1528. statistical time based profiling.
  1529. Param: "sleep" - profile D-state sleeping (millisecs).
  1530. Requires CONFIG_SCHEDSTATS
  1531. Param: "kvm" - profile VM exits.
  1532. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1533. before loading.
  1534. See Documentation/blockdev/ramdisk.txt.
  1535. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1536. probe for; one of (bare|imps|exps|lifebook|any).
  1537. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1538. per second.
  1539. psmouse.resetafter= [HW,MOUSE]
  1540. Try to reset the device after so many bad packets
  1541. (0 = never).
  1542. psmouse.resolution=
  1543. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1544. psmouse.smartscroll=
  1545. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1546. 0 = disabled, 1 = enabled (default).
  1547. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1548. Format:
  1549. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1550. pt. [PARIDE]
  1551. See Documentation/blockdev/paride.txt.
  1552. pty.legacy_count=
  1553. [KNL] Number of legacy pty's. Overwrites compiled-in
  1554. default number.
  1555. quiet [KNL] Disable most log messages
  1556. r128= [HW,DRM]
  1557. raid= [HW,RAID]
  1558. See Documentation/md.txt.
  1559. ramdisk_blocksize= [RAM]
  1560. See Documentation/blockdev/ramdisk.txt.
  1561. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1562. See Documentation/blockdev/ramdisk.txt.
  1563. rcupdate.blimit= [KNL,BOOT]
  1564. Set maximum number of finished RCU callbacks to process
  1565. in one batch.
  1566. rcupdate.qhimark= [KNL,BOOT]
  1567. Set threshold of queued
  1568. RCU callbacks over which batch limiting is disabled.
  1569. rcupdate.qlowmark= [KNL,BOOT]
  1570. Set threshold of queued RCU callbacks below which
  1571. batch limiting is re-enabled.
  1572. rdinit= [KNL]
  1573. Format: <full_path>
  1574. Run specified binary instead of /init from the ramdisk,
  1575. used for early userspace startup. See initrd.
  1576. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1577. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1578. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1579. relax_domain_level=
  1580. [KNL, SMP] Set scheduler's default relax_domain_level.
  1581. See Documentation/cgroups/cpusets.txt.
  1582. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1583. reservetop= [X86-32]
  1584. Format: nn[KMG]
  1585. Reserves a hole at the top of the kernel virtual
  1586. address space.
  1587. reset_devices [KNL] Force drivers to reset the underlying device
  1588. during initialization.
  1589. resume= [SWSUSP]
  1590. Specify the partition device for software suspend
  1591. resume_offset= [SWSUSP]
  1592. Specify the offset from the beginning of the partition
  1593. given by "resume=" at which the swap header is located,
  1594. in <PAGE_SIZE> units (needed only for swap files).
  1595. See Documentation/power/swsusp-and-swap-files.txt
  1596. retain_initrd [RAM] Keep initrd memory after extraction
  1597. rhash_entries= [KNL,NET]
  1598. Set number of hash buckets for route cache
  1599. riscom8= [HW,SERIAL]
  1600. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1601. ro [KNL] Mount root device read-only on boot
  1602. root= [KNL] Root filesystem
  1603. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1604. mount the root filesystem
  1605. rootflags= [KNL] Set root filesystem mount option string
  1606. rootfstype= [KNL] Set root filesystem type
  1607. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1608. Useful for devices that are detected asynchronously
  1609. (e.g. USB and MMC devices).
  1610. root_plug.vendor_id=
  1611. [ROOTPLUG] Override the default vendor ID
  1612. root_plug.product_id=
  1613. [ROOTPLUG] Override the default product ID
  1614. root_plug.debug=
  1615. [ROOTPLUG] Enable debugging output
  1616. rw [KNL] Mount root device read-write on boot
  1617. S [KNL] Run init in single mode
  1618. sa1100ir [NET]
  1619. See drivers/net/irda/sa1100_ir.c.
  1620. sbni= [NET] Granch SBNI12 leased line adapter
  1621. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1622. Format: <io>[,<timeout>[,<isapnp>]]
  1623. scsi_debug_*= [SCSI]
  1624. See drivers/scsi/scsi_debug.c.
  1625. scsi_default_dev_flags=
  1626. [SCSI] SCSI default device flags
  1627. Format: <integer>
  1628. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1629. Format: <vendor>:<model>:<flags>
  1630. (flags are integer value)
  1631. scsi_logging_level= [SCSI] a bit mask of logging levels
  1632. See drivers/scsi/scsi_logging.h for bits. Also
  1633. settable via sysctl at dev.scsi.logging_level
  1634. (/proc/sys/dev/scsi/logging_level).
  1635. There is also a nice 'scsi_logging_level' script in the
  1636. S390-tools package, available for download at
  1637. http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
  1638. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1639. discovered. async scans them in kernel threads,
  1640. allowing boot to proceed. none ignores them, expecting
  1641. user space to do the scan.
  1642. security= [SECURITY] Choose a security module to enable at boot.
  1643. If this boot parameter is not specified, only the first
  1644. security module asking for security registration will be
  1645. loaded. An invalid security module name will be treated
  1646. as if no module has been chosen.
  1647. selinux= [SELINUX] Disable or enable SELinux at boot time.
  1648. Format: { "0" | "1" }
  1649. See security/selinux/Kconfig help text.
  1650. 0 -- disable.
  1651. 1 -- enable.
  1652. Default value is set via kernel config option.
  1653. If enabled at boot time, /selinux/disable can be used
  1654. later to disable prior to initial policy load.
  1655. serialnumber [BUGS=X86-32]
  1656. shapers= [NET]
  1657. Maximal number of shapers.
  1658. show_msr= [x86] show boot-time MSR settings
  1659. Format: { <integer> }
  1660. Show boot-time (BIOS-initialized) MSR settings.
  1661. The parameter means the number of CPUs to show,
  1662. for example 1 means boot CPU only.
  1663. sim710= [SCSI,HW]
  1664. See header of drivers/scsi/sim710.c.
  1665. simeth= [IA-64]
  1666. simscsi=
  1667. slram= [HW,MTD]
  1668. slub_debug[=options[,slabs]] [MM, SLUB]
  1669. Enabling slub_debug allows one to determine the
  1670. culprit if slab objects become corrupted. Enabling
  1671. slub_debug can create guard zones around objects and
  1672. may poison objects when not in use. Also tracks the
  1673. last alloc / free. For more information see
  1674. Documentation/vm/slub.txt.
  1675. slub_max_order= [MM, SLUB]
  1676. Determines the maximum allowed order for slabs.
  1677. A high setting may cause OOMs due to memory
  1678. fragmentation. For more information see
  1679. Documentation/vm/slub.txt.
  1680. slub_min_objects= [MM, SLUB]
  1681. The minimum number of objects per slab. SLUB will
  1682. increase the slab order up to slub_max_order to
  1683. generate a sufficiently large slab able to contain
  1684. the number of objects indicated. The higher the number
  1685. of objects the smaller the overhead of tracking slabs
  1686. and the less frequently locks need to be acquired.
  1687. For more information see Documentation/vm/slub.txt.
  1688. slub_min_order= [MM, SLUB]
  1689. Determines the mininum page order for slabs. Must be
  1690. lower than slub_max_order.
  1691. For more information see Documentation/vm/slub.txt.
  1692. slub_nomerge [MM, SLUB]
  1693. Disable merging of slabs with similar size. May be
  1694. necessary if there is some reason to distinguish
  1695. allocs to different slabs. Debug options disable
  1696. merging on their own.
  1697. For more information see Documentation/vm/slub.txt.
  1698. smart2= [HW]
  1699. Format: <io1>[,<io2>[,...,<io8>]]
  1700. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1701. attempt to substitute SMP alternatives once at boot.
  1702. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1703. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1704. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1705. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1706. smsc-ircc2.ircc_irq= [HW] IRQ line
  1707. smsc-ircc2.ircc_dma= [HW] DMA channel
  1708. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1709. 0: Toshiba Satellite 1800 (GP data pin select)
  1710. 1: Fast pin select (default)
  1711. 2: ATC IRMode
  1712. snd-ad1816a= [HW,ALSA]
  1713. snd-ad1848= [HW,ALSA]
  1714. snd-ali5451= [HW,ALSA]
  1715. snd-als100= [HW,ALSA]
  1716. snd-als4000= [HW,ALSA]
  1717. snd-azt2320= [HW,ALSA]
  1718. snd-cmi8330= [HW,ALSA]
  1719. snd-cmipci= [HW,ALSA]
  1720. snd-cs4231= [HW,ALSA]
  1721. snd-cs4232= [HW,ALSA]
  1722. snd-cs4236= [HW,ALSA]
  1723. snd-cs4281= [HW,ALSA]
  1724. snd-cs46xx= [HW,ALSA]
  1725. snd-dt019x= [HW,ALSA]
  1726. snd-dummy= [HW,ALSA]
  1727. snd-emu10k1= [HW,ALSA]
  1728. snd-ens1370= [HW,ALSA]
  1729. snd-ens1371= [HW,ALSA]
  1730. snd-es968= [HW,ALSA]
  1731. snd-es1688= [HW,ALSA]
  1732. snd-es18xx= [HW,ALSA]
  1733. snd-es1938= [HW,ALSA]
  1734. snd-es1968= [HW,ALSA]
  1735. snd-fm801= [HW,ALSA]
  1736. snd-gusclassic= [HW,ALSA]
  1737. snd-gusextreme= [HW,ALSA]
  1738. snd-gusmax= [HW,ALSA]
  1739. snd-hdsp= [HW,ALSA]
  1740. snd-ice1712= [HW,ALSA]
  1741. snd-intel8x0= [HW,ALSA]
  1742. snd-interwave= [HW,ALSA]
  1743. snd-interwave-stb=
  1744. [HW,ALSA]
  1745. snd-korg1212= [HW,ALSA]
  1746. snd-maestro3= [HW,ALSA]
  1747. snd-mpu401= [HW,ALSA]
  1748. snd-mtpav= [HW,ALSA]
  1749. snd-nm256= [HW,ALSA]
  1750. snd-opl3sa2= [HW,ALSA]
  1751. snd-opti92x-ad1848=
  1752. [HW,ALSA]
  1753. snd-opti92x-cs4231=
  1754. [HW,ALSA]
  1755. snd-opti93x= [HW,ALSA]
  1756. snd-pmac= [HW,ALSA]
  1757. snd-rme32= [HW,ALSA]
  1758. snd-rme96= [HW,ALSA]
  1759. snd-rme9652= [HW,ALSA]
  1760. snd-sb8= [HW,ALSA]
  1761. snd-sb16= [HW,ALSA]
  1762. snd-sbawe= [HW,ALSA]
  1763. snd-serial= [HW,ALSA]
  1764. snd-sgalaxy= [HW,ALSA]
  1765. snd-sonicvibes= [HW,ALSA]
  1766. snd-sun-amd7930=
  1767. [HW,ALSA]
  1768. snd-sun-cs4231= [HW,ALSA]
  1769. snd-trident= [HW,ALSA]
  1770. snd-usb-audio= [HW,ALSA,USB]
  1771. snd-via82xx= [HW,ALSA]
  1772. snd-virmidi= [HW,ALSA]
  1773. snd-wavefront= [HW,ALSA]
  1774. snd-ymfpci= [HW,ALSA]
  1775. softlockup_panic=
  1776. [KNL] Should the soft-lockup detector generate panics.
  1777. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1778. See Documentation/sonypi.txt
  1779. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1780. See Documentation/serial/specialix.txt.
  1781. spia_io_base= [HW,MTD]
  1782. spia_fio_base=
  1783. spia_pedr=
  1784. spia_peddr=
  1785. sscape= [HW,OSS]
  1786. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1787. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1788. See Documentation/scsi/st.txt.
  1789. stacktrace [FTRACE]
  1790. Enabled the stack tracer on boot up.
  1791. sti= [PARISC,HW]
  1792. Format: <num>
  1793. Set the STI (builtin display/keyboard on the HP-PARISC
  1794. machines) console (graphic card) which should be used
  1795. as the initial boot-console.
  1796. See also comment in drivers/video/console/sticore.c.
  1797. sti_font= [HW]
  1798. See comment in drivers/video/console/sticore.c.
  1799. stifb= [HW]
  1800. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1801. sunrpc.pool_mode=
  1802. [NFS]
  1803. Control how the NFS server code allocates CPUs to
  1804. service thread pools. Depending on how many NICs
  1805. you have and where their interrupts are bound, this
  1806. option will affect which CPUs will do NFS serving.
  1807. Note: this parameter cannot be changed while the
  1808. NFS server is running.
  1809. auto the server chooses an appropriate mode
  1810. automatically using heuristics
  1811. global a single global pool contains all CPUs
  1812. percpu one pool for each CPU
  1813. pernode one pool for each NUMA node (equivalent
  1814. to global on non-NUMA machines)
  1815. swiotlb= [IA-64] Number of I/O TLB slabs
  1816. switches= [HW,M68k]
  1817. sym53c416= [HW,SCSI]
  1818. See header of drivers/scsi/sym53c416.c.
  1819. sysrq_always_enabled
  1820. [KNL]
  1821. Ignore sysrq setting - this boot parameter will
  1822. neutralize any effect of /proc/sys/kernel/sysrq.
  1823. Useful for debugging.
  1824. t128= [HW,SCSI]
  1825. See header of drivers/scsi/t128.c.
  1826. tdfx= [HW,DRM]
  1827. test_suspend= [SUSPEND]
  1828. Specify "mem" (for Suspend-to-RAM) or "standby" (for
  1829. standby suspend) as the system sleep state to briefly
  1830. enter during system startup. The system is woken from
  1831. this state using a wakeup-capable RTC alarm.
  1832. thash_entries= [KNL,NET]
  1833. Set number of hash buckets for TCP connection
  1834. thermal.act= [HW,ACPI]
  1835. -1: disable all active trip points in all thermal zones
  1836. <degrees C>: override all lowest active trip points
  1837. thermal.crt= [HW,ACPI]
  1838. -1: disable all critical trip points in all thermal zones
  1839. <degrees C>: override all critical trip points
  1840. thermal.nocrt= [HW,ACPI]
  1841. Set to disable actions on ACPI thermal zone
  1842. critical and hot trip points.
  1843. thermal.off= [HW,ACPI]
  1844. 1: disable ACPI thermal control
  1845. thermal.psv= [HW,ACPI]
  1846. -1: disable all passive trip points
  1847. <degrees C>: override all passive trip points to this
  1848. value
  1849. thermal.tzp= [HW,ACPI]
  1850. Specify global default ACPI thermal zone polling rate
  1851. <deci-seconds>: poll all this frequency
  1852. 0: no polling (default)
  1853. tmscsim= [HW,SCSI]
  1854. See comment before function dc390_setup() in
  1855. drivers/scsi/tmscsim.c.
  1856. topology= [S390]
  1857. Format: {off | on}
  1858. Specify if the kernel should make use of the cpu
  1859. topology informations if the hardware supports these.
  1860. The scheduler will make use of these informations and
  1861. e.g. base its process migration decisions on it.
  1862. Default is off.
  1863. tp720= [HW,PS2]
  1864. trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
  1865. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1866. Format:
  1867. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1868. tsc= Disable clocksource-must-verify flag for TSC.
  1869. Format: <string>
  1870. [x86] reliable: mark tsc clocksource as reliable, this
  1871. disables clocksource verification at runtime.
  1872. Used to enable high-resolution timer mode on older
  1873. hardware, and in virtualized environment.
  1874. turbografx.map[2|3]= [HW,JOY]
  1875. TurboGraFX parallel port interface
  1876. Format:
  1877. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1878. See also Documentation/input/joystick-parport.txt
  1879. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1880. See header of drivers/scsi/u14-34f.c.
  1881. uart401= [HW,OSS]
  1882. Format: <io>,<irq>
  1883. uart6850= [HW,OSS]
  1884. Format: <io>,<irq>
  1885. uhci-hcd.ignore_oc=
  1886. [USB] Ignore overcurrent events (default N).
  1887. Some badly-designed motherboards generate lots of
  1888. bogus events, for ports that aren't wired to
  1889. anything. Set this parameter to avoid log spamming.
  1890. Note that genuine overcurrent events won't be
  1891. reported either.
  1892. unknown_nmi_panic
  1893. [X86]
  1894. Set unknown_nmi_panic=1 early on boot.
  1895. usbcore.autosuspend=
  1896. [USB] The autosuspend time delay (in seconds) used
  1897. for newly-detected USB devices (default 2). This
  1898. is the time required before an idle device will be
  1899. autosuspended. Devices for which the delay is set
  1900. to a negative value won't be autosuspended at all.
  1901. usbcore.usbfs_snoop=
  1902. [USB] Set to log all usbfs traffic (default 0 = off).
  1903. usbcore.blinkenlights=
  1904. [USB] Set to cycle leds on hubs (default 0 = off).
  1905. usbcore.old_scheme_first=
  1906. [USB] Start with the old device initialization
  1907. scheme (default 0 = off).
  1908. usbcore.use_both_schemes=
  1909. [USB] Try the other device initialization scheme
  1910. if the first one fails (default 1 = enabled).
  1911. usbcore.initial_descriptor_timeout=
  1912. [USB] Specifies timeout for the initial 64-byte
  1913. USB_REQ_GET_DESCRIPTOR request in milliseconds
  1914. (default 5000 = 5.0 seconds).
  1915. usbhid.mousepoll=
  1916. [USBHID] The interval which mice are to be polled at.
  1917. usb-storage.delay_use=
  1918. [UMS] The delay in seconds before a new device is
  1919. scanned for Logical Units (default 5).
  1920. usb-storage.quirks=
  1921. [UMS] A list of quirks entries to supplement or
  1922. override the built-in unusual_devs list. List
  1923. entries are separated by commas. Each entry has
  1924. the form VID:PID:Flags where VID and PID are Vendor
  1925. and Product ID values (4-digit hex numbers) and
  1926. Flags is a set of characters, each corresponding
  1927. to a common usb-storage quirk flag as follows:
  1928. a = SANE_SENSE (collect more than 18 bytes
  1929. of sense data);
  1930. c = FIX_CAPACITY (decrease the reported
  1931. device capacity by one sector);
  1932. h = CAPACITY_HEURISTICS (decrease the
  1933. reported device capacity by one
  1934. sector if the number is odd);
  1935. i = IGNORE_DEVICE (don't bind to this
  1936. device);
  1937. l = NOT_LOCKABLE (don't try to lock and
  1938. unlock ejectable media);
  1939. m = MAX_SECTORS_64 (don't transfer more
  1940. than 64 sectors = 32 KB at a time);
  1941. o = CAPACITY_OK (accept the capacity
  1942. reported by the device);
  1943. r = IGNORE_RESIDUE (the device reports
  1944. bogus residue values);
  1945. s = SINGLE_LUN (the device has only one
  1946. Logical Unit);
  1947. w = NO_WP_DETECT (don't test whether the
  1948. medium is write-protected).
  1949. Example: quirks=0419:aaf5:rl,0421:0433:rc
  1950. vdso= [X86,SH]
  1951. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1952. vdso=1: enable VDSO (default)
  1953. vdso=0: disable VDSO mapping
  1954. vdso32= [X86]
  1955. vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
  1956. vdso32=1: enable 32-bit VDSO (default)
  1957. vdso32=0: disable 32-bit VDSO mapping
  1958. vector= [IA-64,SMP]
  1959. vector=percpu: enable percpu vector domain
  1960. video= [FB] Frame buffer configuration
  1961. See Documentation/fb/modedb.txt.
  1962. vga= [BOOT,X86-32] Select a particular video mode
  1963. See Documentation/x86/boot.txt and
  1964. Documentation/svga.txt.
  1965. Use vga=ask for menu.
  1966. This is actually a boot loader parameter; the value is
  1967. passed to the kernel using a special protocol.
  1968. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1969. size of <nn>. This can be used to increase the
  1970. minimum size (128MB on x86). It can also be used to
  1971. decrease the size and leave more room for directly
  1972. mapped kernel RAM.
  1973. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1974. Format: <command>
  1975. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1976. Format: <command>
  1977. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1978. Format: <command>
  1979. vt.default_blu= [VT]
  1980. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  1981. Change the default blue palette of the console.
  1982. This is a 16-member array composed of values
  1983. ranging from 0-255.
  1984. vt.default_grn= [VT]
  1985. Format: <green0>,<green1>,<green2>,...,<green15>
  1986. Change the default green palette of the console.
  1987. This is a 16-member array composed of values
  1988. ranging from 0-255.
  1989. vt.default_red= [VT]
  1990. Format: <red0>,<red1>,<red2>,...,<red15>
  1991. Change the default red palette of the console.
  1992. This is a 16-member array composed of values
  1993. ranging from 0-255.
  1994. vt.default_utf8=
  1995. [VT]
  1996. Format=<0|1>
  1997. Set system-wide default UTF-8 mode for all tty's.
  1998. Default is 1, i.e. UTF-8 mode is enabled for all
  1999. newly opened terminals.
  2000. waveartist= [HW,OSS]
  2001. Format: <io>,<irq>,<dma>,<dma2>
  2002. wd33c93= [HW,SCSI]
  2003. See header of drivers/scsi/wd33c93.c.
  2004. wd7000= [HW,SCSI]
  2005. See header of drivers/scsi/wd7000.c.
  2006. wdt= [WDT] Watchdog
  2007. See Documentation/watchdog/wdt.txt.
  2008. x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
  2009. default x2apic cluster mode on platforms
  2010. supporting x2apic.
  2011. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  2012. xd_geo= See header of drivers/block/xd.c.
  2013. xirc2ps_cs= [NET,PCMCIA]
  2014. Format:
  2015. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  2016. ______________________________________________________________________
  2017. TODO:
  2018. Add documentation for ALSA options.
  2019. Add more DRM drivers.