kernel-parameters.txt 54 KB

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  1. Kernel Parameters
  2. ~~~~~~~~~~~~~~~~~
  3. The following is a consolidated list of the kernel parameters as implemented
  4. (mostly) by the __setup() macro and sorted into English Dictionary order
  5. (defined as ignoring all punctuation and sorting digits before letters in a
  6. case insensitive manner), and with descriptions where known.
  7. Module parameters for loadable modules are specified only as the
  8. parameter name with optional '=' and value as appropriate, such as:
  9. modprobe usbcore blinkenlights=1
  10. Module parameters for modules that are built into the kernel image
  11. are specified on the kernel command line with the module name plus
  12. '.' plus parameter name, with '=' and value if appropriate, such as:
  13. usbcore.blinkenlights=1
  14. This document may not be entirely up to date and comprehensive. The command
  15. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  16. module. Loadable modules, after being loaded into the running kernel, also
  17. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  18. parameters may be changed at runtime by the command
  19. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  20. The parameters listed below are only valid if certain kernel build options were
  21. enabled and if respective hardware is present. The text in square brackets at
  22. the beginning of each description states the restrictions within which a
  23. parameter is applicable:
  24. ACPI ACPI support is enabled.
  25. ALSA ALSA sound support is enabled.
  26. APIC APIC support is enabled.
  27. APM Advanced Power Management support is enabled.
  28. AX25 Appropriate AX.25 support is enabled.
  29. CD Appropriate CD support is enabled.
  30. DRM Direct Rendering Management support is enabled.
  31. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  32. EFI EFI Partitioning (GPT) is enabled
  33. EIDE EIDE/ATAPI support is enabled.
  34. FB The frame buffer device is enabled.
  35. HW Appropriate hardware is enabled.
  36. IA-32 IA-32 aka i386 architecture is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LIBATA Libata driver is enabled
  44. LP Printer support is enabled.
  45. LOOP Loopback device support is enabled.
  46. M68k M68k architecture is enabled.
  47. These options have more detailed description inside of
  48. Documentation/m68k/kernel-options.txt.
  49. MCA MCA bus support is enabled.
  50. MDA MDA console support is enabled.
  51. MOUSE Appropriate mouse support is enabled.
  52. MSI Message Signaled Interrupts (PCI).
  53. MTD MTD support is enabled.
  54. NET Appropriate network support is enabled.
  55. NUMA NUMA support is enabled.
  56. GENERIC_TIME The generic timeofday code is enabled.
  57. NFS Appropriate NFS support is enabled.
  58. OSS OSS sound support is enabled.
  59. PARIDE The ParIDE subsystem is enabled.
  60. PARISC The PA-RISC architecture is enabled.
  61. PCI PCI bus support is enabled.
  62. PCMCIA The PCMCIA subsystem is enabled.
  63. PNP Plug & Play support is enabled.
  64. PPC PowerPC architecture is enabled.
  65. PPT Parallel port support is enabled.
  66. PS2 Appropriate PS/2 support is enabled.
  67. RAM RAM disk support is enabled.
  68. S390 S390 architecture is enabled.
  69. SCSI Appropriate SCSI support is enabled.
  70. A lot of drivers has their options described inside of
  71. Documentation/scsi/.
  72. SELINUX SELinux support is enabled.
  73. SERIAL Serial support is enabled.
  74. SMP The kernel is an SMP kernel.
  75. SPARC Sparc architecture is enabled.
  76. SWSUSP Software suspend is enabled.
  77. TS Appropriate touchscreen support is enabled.
  78. USB USB support is enabled.
  79. USBHID USB Human Interface Device support is enabled.
  80. V4L Video For Linux support is enabled.
  81. VGA The VGA console has been enabled.
  82. VT Virtual terminal support is enabled.
  83. WDT Watchdog support is enabled.
  84. XT IBM PC/XT MFM hard disk support is enabled.
  85. X86-64 X86-64 architecture is enabled.
  86. More X86-64 boot options can be found in
  87. Documentation/x86_64/boot-options.txt .
  88. In addition, the following text indicates that the option:
  89. BUGS= Relates to possible processor bugs on the said processor.
  90. KNL Is a kernel start-up parameter.
  91. BOOT Is a boot loader parameter.
  92. Parameters denoted with BOOT are actually interpreted by the boot
  93. loader, and have no meaning to the kernel directly.
  94. Do not modify the syntax of boot loader parameters without extreme
  95. need or coordination with <Documentation/i386/boot.txt>.
  96. There are also arch-specific kernel-parameters not documented here.
  97. See for example <Documentation/x86_64/boot-options.txt>.
  98. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  99. a trailing = on the name of any parameter states that that parameter will
  100. be entered as an environment variable, whereas its absence indicates that
  101. it will appear as a kernel argument readable via /proc/cmdline by programs
  102. running once the system is up.
  103. The number of kernel parameters is not limited, but the length of the
  104. complete command line (parameters including spaces etc.) is limited to
  105. a fixed number of characters. This limit depends on the architecture
  106. and is between 256 and 4096 characters. It is defined in the file
  107. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  108. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  109. See header of drivers/scsi/53c7xx.c.
  110. See also Documentation/scsi/ncr53c7xx.txt.
  111. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  112. Format: { force | off | ht | strict | noirq }
  113. force -- enable ACPI if default was off
  114. off -- disable ACPI if default was on
  115. noirq -- do not use ACPI for IRQ routing
  116. ht -- run only enough ACPI to enable Hyper Threading
  117. strict -- Be less tolerant of platforms that are not
  118. strictly ACPI specification compliant.
  119. See also Documentation/pm.txt, pci=noacpi
  120. acpi_sleep= [HW,ACPI] Sleep options
  121. Format: { s3_bios, s3_mode }
  122. See Documentation/power/video.txt
  123. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  124. Format: { level | edge | high | low }
  125. acpi_irq_balance [HW,ACPI]
  126. ACPI will balance active IRQs
  127. default in APIC mode
  128. acpi_irq_nobalance [HW,ACPI]
  129. ACPI will not move active IRQs (default)
  130. default in PIC mode
  131. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  132. use by PCI
  133. Format: <irq>,<irq>...
  134. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  135. Format: <irq>,<irq>...
  136. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  137. Format: To spoof as Windows 98: ="Microsoft Windows"
  138. acpi_osi= [HW,ACPI] empty param disables _OSI
  139. acpi_serialize [HW,ACPI] force serialization of AML methods
  140. acpi_skip_timer_override [HW,ACPI]
  141. Recognize and ignore IRQ0/pin2 Interrupt Override.
  142. For broken nForce2 BIOS resulting in XT-PIC timer.
  143. acpi_use_timer_override [HW,ACPI}
  144. Use timer override. For some broken Nvidia NF5 boards
  145. that require a timer override, but don't have
  146. HPET
  147. acpi_dbg_layer= [HW,ACPI]
  148. Format: <int>
  149. Each bit of the <int> indicates an ACPI debug layer,
  150. 1: enable, 0: disable. It is useful for boot time
  151. debugging. After system has booted up, it can be set
  152. via /proc/acpi/debug_layer.
  153. acpi_dbg_level= [HW,ACPI]
  154. Format: <int>
  155. Each bit of the <int> indicates an ACPI debug level,
  156. 1: enable, 0: disable. It is useful for boot time
  157. debugging. After system has booted up, it can be set
  158. via /proc/acpi/debug_level.
  159. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  160. acpi_generic_hotkey [HW,ACPI]
  161. Allow consolidated generic hotkey driver to
  162. override platform specific driver.
  163. See also Documentation/acpi-hotkey.txt.
  164. acpi_pm_good [IA-32,X86-64]
  165. Override the pmtimer bug detection: force the kernel
  166. to assume that this machine's pmtimer latches its value
  167. and always returns good values.
  168. enable_timer_pin_1 [i386,x86-64]
  169. Enable PIN 1 of APIC timer
  170. Can be useful to work around chipset bugs
  171. (in particular on some ATI chipsets).
  172. The kernel tries to set a reasonable default.
  173. disable_timer_pin_1 [i386,x86-64]
  174. Disable PIN 1 of APIC timer
  175. Can be useful to work around chipset bugs.
  176. ad1816= [HW,OSS]
  177. Format: <io>,<irq>,<dma>,<dma2>
  178. See also Documentation/sound/oss/AD1816.
  179. ad1848= [HW,OSS]
  180. Format: <io>,<irq>,<dma>,<dma2>,<type>
  181. adlib= [HW,OSS]
  182. Format: <io>
  183. advansys= [HW,SCSI]
  184. See header of drivers/scsi/advansys.c.
  185. advwdt= [HW,WDT] Advantech WDT
  186. Format: <iostart>,<iostop>
  187. aedsp16= [HW,OSS] Audio Excel DSP 16
  188. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  189. See also header of sound/oss/aedsp16.c.
  190. aha152x= [HW,SCSI]
  191. See Documentation/scsi/aha152x.txt.
  192. aha1542= [HW,SCSI]
  193. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  194. aic7xxx= [HW,SCSI]
  195. See Documentation/scsi/aic7xxx.txt.
  196. aic79xx= [HW,SCSI]
  197. See Documentation/scsi/aic79xx.txt.
  198. amijoy.map= [HW,JOY] Amiga joystick support
  199. Map of devices attached to JOY0DAT and JOY1DAT
  200. Format: <a>,<b>
  201. See also Documentation/kernel/input/joystick.txt
  202. analog.map= [HW,JOY] Analog joystick and gamepad support
  203. Specifies type or capabilities of an analog joystick
  204. connected to one of 16 gameports
  205. Format: <type1>,<type2>,..<type16>
  206. apc= [HW,SPARC]
  207. Power management functions (SPARCstation-4/5 + deriv.)
  208. Format: noidle
  209. Disable APC CPU standby support. SPARCstation-Fox does
  210. not play well with APC CPU idle - disable it if you have
  211. APC and your system crashes randomly.
  212. apic= [APIC,i386] Change the output verbosity whilst booting
  213. Format: { quiet (default) | verbose | debug }
  214. Change the amount of debugging information output
  215. when initialising the APIC and IO-APIC components.
  216. apm= [APM] Advanced Power Management
  217. See header of arch/i386/kernel/apm.c.
  218. applicom= [HW]
  219. Format: <mem>,<irq>
  220. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  221. Format: <io>,<irq>,<nodeID>
  222. ataflop= [HW,M68k]
  223. atarimouse= [HW,MOUSE] Atari Mouse
  224. atascsi= [HW,SCSI] Atari SCSI
  225. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  226. EzKey and similar keyboards
  227. atkbd.reset= [HW] Reset keyboard during initialization
  228. atkbd.set= [HW] Select keyboard code set
  229. Format: <int> (2 = AT (default), 3 = PS/2)
  230. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  231. keyboards
  232. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  233. Format: <bool> (0 = real, 1 = synthetic (default))
  234. atkbd.softrepeat= [HW]
  235. Use software keyboard repeat
  236. autotest [IA64]
  237. aztcd= [HW,CD] Aztech CD268 CDROM driver
  238. Format: <io>,0x79 (?)
  239. baycom_epp= [HW,AX25]
  240. Format: <io>,<mode>
  241. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  242. Format: <io>,<mode>
  243. See header of drivers/net/hamradio/baycom_par.c.
  244. baycom_ser_fdx= [HW,AX25]
  245. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  246. Format: <io>,<irq>,<mode>[,<baud>]
  247. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  248. baycom_ser_hdx= [HW,AX25]
  249. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  250. Format: <io>,<irq>,<mode>
  251. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  252. blkmtd_device= [HW,MTD]
  253. blkmtd_erasesz=
  254. blkmtd_ro=
  255. blkmtd_bs=
  256. blkmtd_count=
  257. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  258. bttv.radio= Most important insmod options are available as
  259. kernel args too.
  260. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  261. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  262. BusLogic= [HW,SCSI]
  263. See drivers/scsi/BusLogic.c, comment before function
  264. BusLogic_ParseDriverOptions().
  265. c101= [NET] Moxa C101 synchronous serial card
  266. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  267. Sometimes CPU hardware bugs make them report the cache
  268. size incorrectly. The kernel will attempt work arounds
  269. to fix known problems, but for some CPUs it is not
  270. possible to determine what the correct size should be.
  271. This option provides an override for these situations.
  272. cdu31a= [HW,CD]
  273. Format: <io>,<irq>[,PAS]
  274. See header of drivers/cdrom/cdu31a.c.
  275. chandev= [HW,NET] Generic channel device initialisation
  276. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  277. Format: { "0" | "1" }
  278. See security/selinux/Kconfig help text.
  279. 0 -- check protection applied by kernel (includes
  280. any implied execute protection).
  281. 1 -- check protection requested by application.
  282. Default value is set via a kernel config option.
  283. Value can be changed at runtime via
  284. /selinux/checkreqprot.
  285. clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
  286. [Deprecated]
  287. Forces specified clocksource (if available) to be used
  288. when calculating gettimeofday(). If specified
  289. clocksource is not available, it defaults to PIT.
  290. Format: { pit | tsc | cyclone | pmtmr }
  291. code_bytes [IA32] How many bytes of object code to print in an
  292. oops report.
  293. Range: 0 - 8192
  294. Default: 64
  295. disable_8254_timer
  296. enable_8254_timer
  297. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  298. over the 8254 in addition to over the IO-APIC. The
  299. kernel tries to set a sensible default.
  300. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  301. Format: disable
  302. cm206= [HW,CD]
  303. Format: { auto | [<io>,][<irq>] }
  304. com20020= [HW,NET] ARCnet - COM20020 chipset
  305. Format:
  306. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  307. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  308. Format: <io>[,<irq>]
  309. com90xx= [HW,NET]
  310. ARCnet - COM90xx chipset (memory-mapped buffers)
  311. Format: <io>[,<irq>[,<memstart>]]
  312. condev= [HW,S390] console device
  313. conmode=
  314. console= [KNL] Output console device and options.
  315. tty<n> Use the virtual console device <n>.
  316. ttyS<n>[,options]
  317. ttyUSB0[,options]
  318. Use the specified serial port. The options are of
  319. the form "bbbbpnf", where "bbbb" is the baud rate,
  320. "p" is parity ("n", "o", or "e"), "n" is number of
  321. bits, and "f" is flow control ("r" for RTS or
  322. omit it). Default is "9600n8".
  323. See Documentation/serial-console.txt for more
  324. information. See
  325. Documentation/networking/netconsole.txt for an
  326. alternative.
  327. uart,io,<addr>[,options]
  328. uart,mmio,<addr>[,options]
  329. Start an early, polled-mode console on the 8250/16550
  330. UART at the specified I/O port or MMIO address,
  331. switching to the matching ttyS device later. The
  332. options are the same as for ttyS, above.
  333. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  334. Format:
  335. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  336. cpia_pp= [HW,PPT]
  337. Format: { parport<nr> | auto | none }
  338. crashkernel=nn[KMG]@ss[KMG]
  339. [KNL] Reserve a chunk of physical memory to
  340. hold a kernel to switch to with kexec on panic.
  341. cs4232= [HW,OSS]
  342. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  343. cs89x0_dma= [HW,NET]
  344. Format: <dma>
  345. cs89x0_media= [HW,NET]
  346. Format: { rj45 | aui | bnc }
  347. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  348. dasd= [HW,NET]
  349. See header of drivers/s390/block/dasd_devmap.c.
  350. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  351. (one device per port)
  352. Format: <port#>,<type>
  353. See also Documentation/input/joystick-parport.txt
  354. debug [KNL] Enable kernel debugging (events log level).
  355. debug_locks_verbose=
  356. [KNL] verbose self-tests
  357. Format=<0|1>
  358. Print debugging info while doing the locking API
  359. self-tests.
  360. We default to 0 (no extra messages), setting it to
  361. 1 will print _a lot_ more information - normally
  362. only useful to kernel developers.
  363. decnet= [HW,NET]
  364. Format: <area>[,<node>]
  365. See also Documentation/networking/decnet.txt.
  366. dhash_entries= [KNL]
  367. Set number of hash buckets for dentry cache.
  368. digi= [HW,SERIAL]
  369. IO parameters + enable/disable command.
  370. digiepca= [HW,SERIAL]
  371. See drivers/char/README.epca and
  372. Documentation/digiepca.txt.
  373. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  374. support available.
  375. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  376. dmasound= [HW,OSS] Sound subsystem buffers
  377. dscc4.setup= [NET]
  378. dtc3181e= [HW,SCSI]
  379. earlyprintk= [IA-32,X86-64]
  380. earlyprintk=vga
  381. earlyprintk=serial[,ttySn[,baudrate]]
  382. Append ",keep" to not disable it when the real console
  383. takes over.
  384. Only vga or serial at a time, not both.
  385. Currently only ttyS0 and ttyS1 are supported.
  386. Interaction with the standard serial driver is not
  387. very good.
  388. The VGA output is eventually overwritten by the real
  389. console.
  390. eata= [HW,SCSI]
  391. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  392. Format: <int>
  393. 0: polling mode
  394. non-0: interrupt mode (default)
  395. eda= [HW,PS2]
  396. edb= [HW,PS2]
  397. edd= [EDD]
  398. Format: {"of[f]" | "sk[ipmbr]"}
  399. See comment in arch/i386/boot/edd.S
  400. eicon= [HW,ISDN]
  401. Format: <id>,<membase>,<irq>
  402. eisa_irq_edge= [PARISC,HW]
  403. See header of drivers/parisc/eisa.c.
  404. elanfreq= [IA-32]
  405. See comment before function elanfreq_setup() in
  406. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  407. elevator= [IOSCHED]
  408. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  409. See Documentation/block/as-iosched.txt and
  410. Documentation/block/deadline-iosched.txt for details.
  411. elfcorehdr= [IA-32, X86_64]
  412. Specifies physical address of start of kernel core
  413. image elf header. Generally kexec loader will
  414. pass this option to capture kernel.
  415. See Documentation/kdump/kdump.txt for details.
  416. enforcing [SELINUX] Set initial enforcing status.
  417. Format: {"0" | "1"}
  418. See security/selinux/Kconfig help text.
  419. 0 -- permissive (log only, no denials).
  420. 1 -- enforcing (deny and log).
  421. Default value is 0.
  422. Value can be changed at runtime via /selinux/enforce.
  423. es1371= [HW,OSS]
  424. Format: <spdif>,[<nomix>,[<amplifier>]]
  425. See also header of sound/oss/es1371.c.
  426. ether= [HW,NET] Ethernet cards parameters
  427. This option is obsoleted by the "netdev=" option, which
  428. has equivalent usage. See its documentation for details.
  429. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  430. Format: <io>[,<irq>]
  431. failslab=
  432. fail_page_alloc=
  433. fail_make_request=[KNL]
  434. General fault injection mechanism.
  435. Format: <interval>,<probability>,<space>,<times>
  436. See also /Documentation/fault-injection/.
  437. fd_mcs= [HW,SCSI]
  438. See header of drivers/scsi/fd_mcs.c.
  439. fdomain= [HW,SCSI]
  440. See header of drivers/scsi/fdomain.c.
  441. floppy= [HW]
  442. See Documentation/floppy.txt.
  443. gamecon.map[2|3]=
  444. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  445. support via parallel port (up to 5 devices per port)
  446. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  447. See also Documentation/input/joystick-parport.txt
  448. gamma= [HW,DRM]
  449. gdth= [HW,SCSI]
  450. See header of drivers/scsi/gdth.c.
  451. gpt [EFI] Forces disk with valid GPT signature but
  452. invalid Protective MBR to be treated as GPT.
  453. gscd= [HW,CD]
  454. Format: <io>
  455. gvp11= [HW,SCSI]
  456. hashdist= [KNL,NUMA] Large hashes allocated during boot
  457. are distributed across NUMA nodes. Defaults on
  458. for IA-64, off otherwise.
  459. Format: 0 | 1 (for off | on)
  460. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  461. hd= [EIDE] (E)IDE hard drive subsystem geometry
  462. Format: <cyl>,<head>,<sect>
  463. hd?= [HW] (E)IDE subsystem
  464. hd?lun= See Documentation/ide.txt.
  465. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  466. size of <nn>. This works even on boxes that have no
  467. highmem otherwise. This also works to reduce highmem
  468. size on bigger boxes.
  469. highres= [KNL] Enable/disable high resolution timer mode.
  470. Valid parameters: "on", "off"
  471. Default: "on"
  472. hisax= [HW,ISDN]
  473. See Documentation/isdn/README.HiSax.
  474. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  475. i8042.direct [HW] Put keyboard port into non-translated mode
  476. i8042.dumbkbd [HW] Pretend that controller can only read data from
  477. keyboard and cannot control its state
  478. (Don't attempt to blink the leds)
  479. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  480. i8042.nokbd [HW] Don't check/create keyboard port
  481. i8042.nomux [HW] Don't check presence of an active multiplexing
  482. controller
  483. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  484. controllers
  485. i8042.panicblink=
  486. [HW] Frequency with which keyboard LEDs should blink
  487. when kernel panics (default is 0.5 sec)
  488. i8042.reset [HW] Reset the controller during init and cleanup
  489. i8042.unlock [HW] Unlock (ignore) the keylock
  490. i810= [HW,DRM]
  491. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  492. indicates that the driver is running on unsupported
  493. hardware.
  494. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  495. does not match list of supported models.
  496. i8k.power_status
  497. [HW] Report power status in /proc/i8k
  498. (disabled by default)
  499. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  500. capability is set.
  501. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  502. See Documentation/mca.txt.
  503. icn= [HW,ISDN]
  504. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  505. ide= [HW] (E)IDE subsystem
  506. Format: ide=nodma or ide=doubler or ide=reverse
  507. See Documentation/ide.txt.
  508. ide?= [HW] (E)IDE subsystem
  509. Format: ide?=noprobe or chipset specific parameters.
  510. See Documentation/ide.txt.
  511. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  512. See Documentation/ide.txt.
  513. idle= [HW]
  514. Format: idle=poll or idle=halt
  515. ignore_loglevel [KNL]
  516. Ignore loglevel setting - this will print /all/
  517. kernel messages to the console. Useful for debugging.
  518. ihash_entries= [KNL]
  519. Set number of hash buckets for inode cache.
  520. in2000= [HW,SCSI]
  521. See header of drivers/scsi/in2000.c.
  522. init= [KNL]
  523. Format: <full_path>
  524. Run specified binary instead of /sbin/init as init
  525. process.
  526. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  527. for working out where the kernel is dying during
  528. startup.
  529. initrd= [BOOT] Specify the location of the initial ramdisk
  530. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  531. Format: <irq>
  532. combined_mode= [HW] control which driver uses IDE ports in combined
  533. mode: legacy IDE driver, libata, or both
  534. (in the libata case, libata.atapi_enabled=1 may be
  535. useful as well). Note that using the ide or libata
  536. options may affect your device naming (e.g. by
  537. changing hdc to sdb).
  538. Format: combined (default), ide, or libata
  539. inttest= [IA64]
  540. io7= [HW] IO7 for Marvel based alpha systems
  541. See comment before marvel_specify_io7 in
  542. arch/alpha/kernel/core_marvel.c.
  543. ip= [IP_PNP]
  544. See Documentation/nfsroot.txt.
  545. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  546. See comment before ip2_setup() in drivers/char/ip2.c.
  547. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  548. See header of drivers/scsi/ips.c.
  549. ports= [IP_VS_FTP] IPVS ftp helper module
  550. Default is 21.
  551. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  552. may be specified.
  553. Format: <port>,<port>....
  554. irqfixup [HW]
  555. When an interrupt is not handled search all handlers
  556. for it. Intended to get systems with badly broken
  557. firmware running.
  558. irqpoll [HW]
  559. When an interrupt is not handled search all handlers
  560. for it. Also check all handlers each timer
  561. interrupt. Intended to get systems with badly broken
  562. firmware running.
  563. isapnp= [ISAPNP]
  564. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  565. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  566. Format:
  567. <cpu number>,...,<cpu number>
  568. or
  569. <cpu number>-<cpu number> (must be a positive range in ascending order)
  570. or a mixture
  571. <cpu number>,...,<cpu number>-<cpu number>
  572. This option can be used to specify one or more CPUs
  573. to isolate from the general SMP balancing and scheduling
  574. algorithms. The only way to move a process onto or off
  575. an "isolated" CPU is via the CPU affinity syscalls.
  576. <cpu number> begins at 0 and the maximum value is
  577. "number of CPUs in system - 1".
  578. This option is the preferred way to isolate CPUs. The
  579. alternative -- manually setting the CPU mask of all
  580. tasks in the system -- can cause problems and
  581. suboptimal load balancer performance.
  582. isp16= [HW,CD]
  583. Format: <io>,<irq>,<dma>,<setup>
  584. iucv= [HW,NET]
  585. js= [HW,JOY] Analog joystick
  586. See Documentation/input/joystick.txt.
  587. keepinitrd [HW,ARM]
  588. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  589. in oops dumps.
  590. l2cr= [PPC]
  591. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  592. disabled it.
  593. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  594. Format: addr:<io>,irq:<irq>
  595. llsc*= [IA64] See function print_params() in
  596. arch/ia64/sn/kernel/llsc4.c.
  597. load_ramdisk= [RAM] List of ramdisks to load from floppy
  598. See Documentation/ramdisk.txt.
  599. lockd.nlm_grace_period=P [NFS] Assign grace period.
  600. Format: <integer>
  601. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  602. Format: <integer>
  603. lockd.nlm_timeout=T [NFS] Assign timeout value.
  604. Format: <integer>
  605. lockd.nlm_udpport=M [NFS] Assign UDP port.
  606. Format: <integer>
  607. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  608. Format: <irq>
  609. loglevel= All Kernel Messages with a loglevel smaller than the
  610. console loglevel will be printed to the console. It can
  611. also be changed with klogd or other programs. The
  612. loglevels are defined as follows:
  613. 0 (KERN_EMERG) system is unusable
  614. 1 (KERN_ALERT) action must be taken immediately
  615. 2 (KERN_CRIT) critical conditions
  616. 3 (KERN_ERR) error conditions
  617. 4 (KERN_WARNING) warning conditions
  618. 5 (KERN_NOTICE) normal but significant condition
  619. 6 (KERN_INFO) informational
  620. 7 (KERN_DEBUG) debug-level messages
  621. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  622. Format: { n | nk | nM }
  623. n must be a power of two. The default size
  624. is set in the kernel config file.
  625. lp=0 [LP] Specify parallel ports to use, e.g,
  626. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  627. lp=reset first parallel port). 'lp=0' disables the
  628. lp=auto printer driver. 'lp=reset' (which can be
  629. specified in addition to the ports) causes
  630. attached printers to be reset. Using
  631. lp=port1,port2,... specifies the parallel ports
  632. to associate lp devices with, starting with
  633. lp0. A port specification may be 'none' to skip
  634. that lp device, or a parport name such as
  635. 'parport0'. Specifying 'lp=auto' instead of a
  636. port specification list means that device IDs
  637. from each port should be examined, to see if
  638. an IEEE 1284-compliant printer is attached; if
  639. so, the driver will manage that printer.
  640. See also header of drivers/char/lp.c.
  641. lpj=n [KNL]
  642. Sets loops_per_jiffy to given constant, thus avoiding
  643. time-consuming boot-time autodetection (up to 250 ms per
  644. CPU). 0 enables autodetection (default). To determine
  645. the correct value for your kernel, boot with normal
  646. autodetection and see what value is printed. Note that
  647. on SMP systems the preset will be applied to all CPUs,
  648. which is likely to cause problems if your CPUs need
  649. significantly divergent settings. An incorrect value
  650. will cause delays in the kernel to be wrong, leading to
  651. unpredictable I/O errors and other breakage. Although
  652. unlikely, in the extreme case this might damage your
  653. hardware.
  654. ltpc= [NET]
  655. Format: <io>,<irq>,<dma>
  656. mac5380= [HW,SCSI] Format:
  657. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  658. mac53c9x= [HW,SCSI] Format:
  659. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  660. machvec= [IA64] Force the use of a particular machine-vector
  661. (machvec) in a generic kernel.
  662. Example: machvec=hpzx1_swiotlb
  663. max_loop= [LOOP] Maximum number of loopback devices that can
  664. be mounted
  665. Format: <1-256>
  666. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  667. should make use of.
  668. Using "nosmp" or "maxcpus=0" will disable SMP
  669. entirely (the MPS table probe still happens, though).
  670. A command-line option of "maxcpus=<NUM>", where <NUM>
  671. is an integer greater than 0, limits the maximum number
  672. of CPUs activated in SMP mode to <NUM>.
  673. Using "maxcpus=1" on an SMP kernel is the trivial
  674. case of an SMP kernel with only one CPU.
  675. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  676. equal to this physical address is ignored.
  677. max_luns= [SCSI] Maximum number of LUNs to probe.
  678. Should be between 1 and 2^32-1.
  679. max_report_luns=
  680. [SCSI] Maximum number of LUNs received.
  681. Should be between 1 and 16384.
  682. mca-pentium [BUGS=IA-32]
  683. mcatest= [IA-64]
  684. mcd= [HW,CD]
  685. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  686. mcdx= [HW,CD]
  687. mce [IA-32] Machine Check Exception
  688. md= [HW] RAID subsystems devices and level
  689. See Documentation/md.txt.
  690. mdacon= [MDA]
  691. Format: <first>,<last>
  692. Specifies range of consoles to be captured by the MDA.
  693. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  694. Amount of memory to be used when the kernel is not able
  695. to see the whole system memory or for test.
  696. [IA-32] Use together with memmap= to avoid physical
  697. address space collisions. Without memmap= PCI devices
  698. could be placed at addresses belonging to unused RAM.
  699. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  700. memory.
  701. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  702. E820 memory map, as specified by the user.
  703. Such memmap=exactmap lines can be constructed based on
  704. BIOS output or other requirements. See the memmap=nn@ss
  705. option description.
  706. memmap=nn[KMG]@ss[KMG]
  707. [KNL] Force usage of a specific region of memory
  708. Region of memory to be used, from ss to ss+nn.
  709. memmap=nn[KMG]#ss[KMG]
  710. [KNL,ACPI] Mark specific memory as ACPI data.
  711. Region of memory to be used, from ss to ss+nn.
  712. memmap=nn[KMG]$ss[KMG]
  713. [KNL,ACPI] Mark specific memory as reserved.
  714. Region of memory to be used, from ss to ss+nn.
  715. meye.*= [HW] Set MotionEye Camera parameters
  716. See Documentation/video4linux/meye.txt.
  717. mga= [HW,DRM]
  718. migration_cost=
  719. [KNL,SMP] debug: override scheduler migration costs
  720. Format: <level-1-usecs>,<level-2-usecs>,...
  721. This debugging option can be used to override the
  722. default scheduler migration cost matrix. The numbers
  723. are indexed by 'CPU domain distance'.
  724. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  725. box will set up an intra-core migration cost of
  726. 1 msec, an inter-core migration cost of 2 msecs,
  727. and an inter-node migration cost of 3 msecs.
  728. WARNING: using the wrong values here can break
  729. scheduler performance, so it's only for scheduler
  730. development purposes, not production environments.
  731. migration_debug=
  732. [KNL,SMP] migration cost auto-detect verbosity
  733. Format=<0|1|2>
  734. If a system's migration matrix reported at bootup
  735. seems erroneous then this option can be used to
  736. increase verbosity of the detection process.
  737. We default to 0 (no extra messages), 1 will print
  738. some more information, and 2 will be really
  739. verbose (probably only useful if you also have a
  740. serial console attached to the system).
  741. migration_factor=
  742. [KNL,SMP] multiply/divide migration costs by a factor
  743. Format=<percent>
  744. This debug option can be used to proportionally
  745. increase or decrease the auto-detected migration
  746. costs for all entries of the migration matrix.
  747. E.g. migration_factor=150 will increase migration
  748. costs by 50%. (and thus the scheduler will be less
  749. eager migrating cache-hot tasks)
  750. migration_factor=80 will decrease migration costs
  751. by 20%. (thus the scheduler will be more eager to
  752. migrate tasks)
  753. WARNING: using the wrong values here can break
  754. scheduler performance, so it's only for scheduler
  755. development purposes, not production environments.
  756. mousedev.tap_time=
  757. [MOUSE] Maximum time between finger touching and
  758. leaving touchpad surface for touch to be considered
  759. a tap and be reported as a left button click (for
  760. touchpads working in absolute mode only).
  761. Format: <msecs>
  762. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  763. reporting absolute coordinates, such as tablets
  764. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  765. reporting absolute coordinates, such as tablets
  766. mpu401= [HW,OSS]
  767. Format: <io>,<irq>
  768. MTD_Partition= [MTD]
  769. Format: <name>,<region-number>,<size>,<offset>
  770. MTD_Region= [MTD] Format:
  771. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  772. mtdparts= [MTD]
  773. See drivers/mtd/cmdline.c.
  774. mtouchusb.raw_coordinates=
  775. [HW] Make the MicroTouch USB driver use raw coordinates
  776. ('y', default) or cooked coordinates ('n')
  777. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  778. NCR_D700= [HW,SCSI]
  779. See header of drivers/scsi/NCR_D700.c.
  780. ncr5380= [HW,SCSI]
  781. ncr53c400= [HW,SCSI]
  782. ncr53c400a= [HW,SCSI]
  783. ncr53c406a= [HW,SCSI]
  784. ncr53c8xx= [HW,SCSI]
  785. netdev= [NET] Network devices parameters
  786. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  787. Note that mem_start is often overloaded to mean
  788. something different and driver-specific.
  789. This usage is only documented in each driver source
  790. file if at all.
  791. nfsaddrs= [NFS]
  792. See Documentation/nfsroot.txt.
  793. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  794. See Documentation/nfsroot.txt.
  795. nfs.callback_tcpport=
  796. [NFS] set the TCP port on which the NFSv4 callback
  797. channel should listen.
  798. nfs.idmap_cache_timeout=
  799. [NFS] set the maximum lifetime for idmapper cache
  800. entries.
  801. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  802. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  803. emulation library even if a 387 maths coprocessor
  804. is present.
  805. noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  806. when set.
  807. Format: <int>
  808. noaliencache [MM, NUMA] Disables the allcoation of alien caches in
  809. the slab allocator. Saves per-node memory, but will
  810. impact performance on real NUMA hardware.
  811. noalign [KNL,ARM]
  812. noapic [SMP,APIC] Tells the kernel to not make use of any
  813. IOAPICs that may be present in the system.
  814. noasync [HW,M68K] Disables async and sync negotiation for
  815. all devices.
  816. nobats [PPC] Do not use BATs for mapping kernel lowmem
  817. on "Classic" PPC cores.
  818. nocache [ARM]
  819. nodelayacct [KNL] Disable per-task delay accounting
  820. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  821. noexec [IA-64]
  822. noexec [IA-32,X86-64]
  823. noexec=on: enable non-executable mappings (default)
  824. noexec=off: disable nn-executable mappings
  825. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  826. register save and restore. The kernel will only save
  827. legacy floating-point registers on task switch.
  828. nohlt [BUGS=ARM]
  829. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  830. instruction doesn't work correctly and not to
  831. use it.
  832. nohalt [IA-64] Tells the kernel not to use the power saving
  833. function PAL_HALT_LIGHT when idle. This increases
  834. power-consumption. On the positive side, it reduces
  835. interrupt wake-up latency, which may improve performance
  836. in certain environments such as networked servers or
  837. real-time systems.
  838. nohz= [KNL] Boottime enable/disable dynamic ticks
  839. Valid arguments: on, off
  840. Default: on
  841. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  842. noirqdebug [IA-32] Disables the code which attempts to detect and
  843. disable unhandled interrupt sources.
  844. no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
  845. broken timer IRQ sources.
  846. noisapnp [ISAPNP] Disables ISA PnP code.
  847. noinitrd [RAM] Tells the kernel not to load any configured
  848. initial RAM disk.
  849. nointroute [IA-64]
  850. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  851. noltlbs [PPC] Do not use large page/tlb entries for kernel
  852. lowmem mapping on PPC40x.
  853. nomca [IA-64] Disable machine check abort handling
  854. nomce [IA-32] Machine Check Exception
  855. noresidual [PPC] Don't use residual data on PReP machines.
  856. noresume [SWSUSP] Disables resume and restores original swap
  857. space.
  858. no-scroll [VGA] Disables scrollback.
  859. This is required for the Braillex ib80-piezo Braille
  860. reader made by F.H. Papenmeier (Germany).
  861. nosbagart [IA-64]
  862. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  863. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  864. nosync [HW,M68K] Disables sync negotiation for all devices.
  865. notsc [BUGS=IA-32] Disable Time Stamp Counter
  866. nousb [USB] Disable the USB subsystem
  867. nowb [ARM]
  868. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  869. opl3= [HW,OSS]
  870. Format: <io>
  871. opl3sa2= [HW,OSS] Format:
  872. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  873. oprofile.timer= [HW]
  874. Use timer interrupt instead of performance counters
  875. optcd= [HW,CD]
  876. Format: <io>
  877. osst= [HW,SCSI] SCSI Tape Driver
  878. Format: <buffer_size>,<write_threshold>
  879. See also Documentation/scsi/st.txt.
  880. panic= [KNL] Kernel behaviour on panic
  881. Format: <timeout>
  882. parkbd.port= [HW] Parallel port number the keyboard adapter is
  883. connected to, default is 0.
  884. Format: <parport#>
  885. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  886. 0 for XT, 1 for AT (default is AT).
  887. Format: <mode>
  888. parport= [HW,PPT] Specify parallel ports. 0 disables.
  889. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  890. Use 'auto' to force the driver to use any
  891. IRQ/DMA settings detected (the default is to
  892. ignore detected IRQ/DMA settings because of
  893. possible conflicts). You can specify the base
  894. address, IRQ, and DMA settings; IRQ and DMA
  895. should be numbers, or 'auto' (for using detected
  896. settings on that particular port), or 'nofifo'
  897. (to avoid using a FIFO even if it is detected).
  898. Parallel ports are assigned in the order they
  899. are specified on the command line, starting
  900. with parport0.
  901. parport_init_mode= [HW,PPT]
  902. Configure VIA parallel port to operate in
  903. a specific mode. This is necessary on Pegasos
  904. computer where firmware has no options for setting
  905. up parallel port mode and sets it to spp.
  906. Currently this function knows 686a and 8231 chips.
  907. Format: [spp|ps2|epp|ecp|ecpepp]
  908. pas2= [HW,OSS] Format:
  909. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  910. pas16= [HW,SCSI]
  911. See header of drivers/scsi/pas16.c.
  912. pause_on_oops=
  913. Halt all CPUs after the first oops has been printed for
  914. the specified number of seconds. This is to be used if
  915. your oopses keep scrolling off the screen.
  916. pcbit= [HW,ISDN]
  917. pcd. [PARIDE]
  918. See header of drivers/block/paride/pcd.c.
  919. See also Documentation/paride.txt.
  920. pci=option[,option...] [PCI] various PCI subsystem options:
  921. off [IA-32] don't probe for the PCI bus
  922. bios [IA-32] force use of PCI BIOS, don't access
  923. the hardware directly. Use this if your machine
  924. has a non-standard PCI host bridge.
  925. nobios [IA-32] disallow use of PCI BIOS, only direct
  926. hardware access methods are allowed. Use this
  927. if you experience crashes upon bootup and you
  928. suspect they are caused by the BIOS.
  929. conf1 [IA-32] Force use of PCI Configuration
  930. Mechanism 1.
  931. conf2 [IA-32] Force use of PCI Configuration
  932. Mechanism 2.
  933. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  934. Configuration
  935. nomsi [MSI] If the PCI_MSI kernel config parameter is
  936. enabled, this kernel boot option can be used to
  937. disable the use of MSI interrupts system-wide.
  938. nosort [IA-32] Don't sort PCI devices according to
  939. order given by the PCI BIOS. This sorting is
  940. done to get a device order compatible with
  941. older kernels.
  942. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  943. routing table. These calls are known to be buggy
  944. on several machines and they hang the machine
  945. when used, but on other computers it's the only
  946. way to get the interrupt routing table. Try
  947. this option if the kernel is unable to allocate
  948. IRQs or discover secondary PCI buses on your
  949. motherboard.
  950. rom [IA-32] Assign address space to expansion ROMs.
  951. Use with caution as certain devices share
  952. address decoders between ROMs and other
  953. resources.
  954. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  955. assigned automatically to PCI devices. You can
  956. make the kernel exclude IRQs of your ISA cards
  957. this way.
  958. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  959. of the PIRQ table (normally generated
  960. by the BIOS) if it is outside the
  961. F0000h-100000h range.
  962. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  963. useful if the kernel is unable to find your
  964. secondary buses and you want to tell it
  965. explicitly which ones they are.
  966. assign-busses [IA-32] Always assign all PCI bus
  967. numbers ourselves, overriding
  968. whatever the firmware may have done.
  969. usepirqmask [IA-32] Honor the possible IRQ mask stored
  970. in the BIOS $PIR table. This is needed on
  971. some systems with broken BIOSes, notably
  972. some HP Pavilion N5400 and Omnibook XE3
  973. notebooks. This will have no effect if ACPI
  974. IRQ routing is enabled.
  975. noacpi [IA-32] Do not use ACPI for IRQ routing
  976. or for PCI scanning.
  977. routeirq Do IRQ routing for all PCI devices.
  978. This is normally done in pci_enable_device(),
  979. so this option is a temporary workaround
  980. for broken drivers that don't call it.
  981. firmware [ARM] Do not re-enumerate the bus but instead
  982. just use the configuration from the
  983. bootloader. This is currently used on
  984. IXP2000 systems where the bus has to be
  985. configured a certain way for adjunct CPUs.
  986. noearly [X86] Don't do any early type 1 scanning.
  987. This might help on some broken boards which
  988. machine check when some devices' config space
  989. is read. But various workarounds are disabled
  990. and some IOMMU drivers will not work.
  991. bfsort Sort PCI devices into breadth-first order.
  992. This sorting is done to get a device
  993. order compatible with older (<= 2.4) kernels.
  994. nobfsort Don't sort PCI devices into breadth-first order.
  995. cbiosize=nn[KMG] The fixed amount of bus space which is
  996. reserved for the CardBus bridge's IO window.
  997. The default value is 256 bytes.
  998. cbmemsize=nn[KMG] The fixed amount of bus space which is
  999. reserved for the CardBus bridge's memory
  1000. window. The default value is 64 megabytes.
  1001. pcmv= [HW,PCMCIA] BadgePAD 4
  1002. pd. [PARIDE]
  1003. See Documentation/paride.txt.
  1004. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1005. boot time.
  1006. Format: { 0 | 1 }
  1007. See arch/parisc/kernel/pdc_chassis.c
  1008. pf. [PARIDE]
  1009. See Documentation/paride.txt.
  1010. pg. [PARIDE]
  1011. See Documentation/paride.txt.
  1012. pirq= [SMP,APIC] Manual mp-table setup
  1013. See Documentation/i386/IO-APIC.txt.
  1014. plip= [PPT,NET] Parallel port network link
  1015. Format: { parport<nr> | timid | 0 }
  1016. See also Documentation/parport.txt.
  1017. pnpacpi= [ACPI]
  1018. { off }
  1019. pnpbios= [ISAPNP]
  1020. { on | off | curr | res | no-curr | no-res }
  1021. pnp_reserve_irq=
  1022. [ISAPNP] Exclude IRQs for the autoconfiguration
  1023. pnp_reserve_dma=
  1024. [ISAPNP] Exclude DMAs for the autoconfiguration
  1025. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1026. Ranges are in pairs (I/O port base and size).
  1027. pnp_reserve_mem=
  1028. [ISAPNP] Exclude memory regions for the
  1029. autoconfiguration.
  1030. Ranges are in pairs (memory base and size).
  1031. profile= [KNL] Enable kernel profiling via /proc/profile
  1032. Format: [schedule,]<number>
  1033. Param: "schedule" - profile schedule points.
  1034. Param: <number> - step/bucket size as a power of 2 for
  1035. statistical time based profiling.
  1036. Param: "sleep" - profile D-state sleeping (millisecs)
  1037. processor.max_cstate= [HW,ACPI]
  1038. Limit processor to maximum C-state
  1039. max_cstate=9 overrides any DMI blacklist limit.
  1040. processor.nocst [HW,ACPI]
  1041. Ignore the _CST method to determine C-states,
  1042. instead using the legacy FADT method
  1043. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1044. before loading.
  1045. See Documentation/ramdisk.txt.
  1046. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1047. probe for; one of (bare|imps|exps|lifebook|any).
  1048. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1049. per second.
  1050. psmouse.resetafter= [HW,MOUSE]
  1051. Try to reset the device after so many bad packets
  1052. (0 = never).
  1053. psmouse.resolution=
  1054. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1055. psmouse.smartscroll=
  1056. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1057. 0 = disabled, 1 = enabled (default).
  1058. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1059. Format:
  1060. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1061. pt. [PARIDE]
  1062. See Documentation/paride.txt.
  1063. quiet [KNL] Disable most log messages
  1064. r128= [HW,DRM]
  1065. raid= [HW,RAID]
  1066. See Documentation/md.txt.
  1067. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1068. See Documentation/ramdisk.txt.
  1069. ramdisk_blocksize= [RAM]
  1070. See Documentation/ramdisk.txt.
  1071. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1072. New name for the ramdisk parameter.
  1073. See Documentation/ramdisk.txt.
  1074. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1075. RCU callbacks to process in one batch.
  1076. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1077. RCU callbacks over which batch limiting is disabled.
  1078. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1079. RCU callbacks below which batch limiting is re-enabled.
  1080. rdinit= [KNL]
  1081. Format: <full_path>
  1082. Run specified binary instead of /init from the ramdisk,
  1083. used for early userspace startup. See initrd.
  1084. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1085. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1086. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1087. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1088. reservetop= [IA-32]
  1089. Format: nn[KMG]
  1090. Reserves a hole at the top of the kernel virtual
  1091. address space.
  1092. reset_devices [KNL] Force drivers to reset the underlying device
  1093. during initialization.
  1094. resume= [SWSUSP]
  1095. Specify the partition device for software suspend
  1096. resume_offset= [SWSUSP]
  1097. Specify the offset from the beginning of the partition
  1098. given by "resume=" at which the swap header is located,
  1099. in <PAGE_SIZE> units (needed only for swap files).
  1100. See Documentation/power/swsusp-and-swap-files.txt
  1101. retain_initrd [RAM] Keep initrd memory after extraction
  1102. rhash_entries= [KNL,NET]
  1103. Set number of hash buckets for route cache
  1104. riscom8= [HW,SERIAL]
  1105. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1106. ro [KNL] Mount root device read-only on boot
  1107. root= [KNL] Root filesystem
  1108. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1109. mount the root filesystem
  1110. rootflags= [KNL] Set root filesystem mount option string
  1111. rootfstype= [KNL] Set root filesystem type
  1112. rw [KNL] Mount root device read-write on boot
  1113. S [KNL] Run init in single mode
  1114. sa1100ir [NET]
  1115. See drivers/net/irda/sa1100_ir.c.
  1116. sb= [HW,OSS]
  1117. Format: <io>,<irq>,<dma>,<dma2>
  1118. sbni= [NET] Granch SBNI12 leased line adapter
  1119. sbpcd= [HW,CD] Soundblaster CD adapter
  1120. Format: <io>,<type>
  1121. See a comment before function sbpcd_setup() in
  1122. drivers/cdrom/sbpcd.c.
  1123. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1124. Format: <io>[,<timeout>[,<isapnp>]]
  1125. scsi_debug_*= [SCSI]
  1126. See drivers/scsi/scsi_debug.c.
  1127. scsi_default_dev_flags=
  1128. [SCSI] SCSI default device flags
  1129. Format: <integer>
  1130. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1131. Format: <vendor>:<model>:<flags>
  1132. (flags are integer value)
  1133. scsi_logging= [SCSI]
  1134. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1135. discovered. async scans them in kernel threads,
  1136. allowing boot to proceed. none ignores them, expecting
  1137. user space to do the scan.
  1138. selinux [SELINUX] Disable or enable SELinux at boot time.
  1139. Format: { "0" | "1" }
  1140. See security/selinux/Kconfig help text.
  1141. 0 -- disable.
  1142. 1 -- enable.
  1143. Default value is set via kernel config option.
  1144. If enabled at boot time, /selinux/disable can be used
  1145. later to disable prior to initial policy load.
  1146. selinux_compat_net =
  1147. [SELINUX] Set initial selinux_compat_net flag value.
  1148. Format: { "0" | "1" }
  1149. 0 -- use new secmark-based packet controls
  1150. 1 -- use legacy packet controls
  1151. Default value is 0 (preferred).
  1152. Value can be changed at runtime via
  1153. /selinux/compat_net.
  1154. serialnumber [BUGS=IA-32]
  1155. sg_def_reserved_size= [SCSI]
  1156. shapers= [NET]
  1157. Maximal number of shapers.
  1158. sim710= [SCSI,HW]
  1159. See header of drivers/scsi/sim710.c.
  1160. simeth= [IA-64]
  1161. simscsi=
  1162. sjcd= [HW,CD]
  1163. Format: <io>,<irq>,<dma>
  1164. See header of drivers/cdrom/sjcd.c.
  1165. slram= [HW,MTD]
  1166. smart2= [HW]
  1167. Format: <io1>[,<io2>[,...,<io8>]]
  1168. snd-ad1816a= [HW,ALSA]
  1169. snd-ad1848= [HW,ALSA]
  1170. snd-ali5451= [HW,ALSA]
  1171. snd-als100= [HW,ALSA]
  1172. snd-als4000= [HW,ALSA]
  1173. snd-azt2320= [HW,ALSA]
  1174. snd-cmi8330= [HW,ALSA]
  1175. snd-cmipci= [HW,ALSA]
  1176. snd-cs4231= [HW,ALSA]
  1177. snd-cs4232= [HW,ALSA]
  1178. snd-cs4236= [HW,ALSA]
  1179. snd-cs4281= [HW,ALSA]
  1180. snd-cs46xx= [HW,ALSA]
  1181. snd-dt019x= [HW,ALSA]
  1182. snd-dummy= [HW,ALSA]
  1183. snd-emu10k1= [HW,ALSA]
  1184. snd-ens1370= [HW,ALSA]
  1185. snd-ens1371= [HW,ALSA]
  1186. snd-es968= [HW,ALSA]
  1187. snd-es1688= [HW,ALSA]
  1188. snd-es18xx= [HW,ALSA]
  1189. snd-es1938= [HW,ALSA]
  1190. snd-es1968= [HW,ALSA]
  1191. snd-fm801= [HW,ALSA]
  1192. snd-gusclassic= [HW,ALSA]
  1193. snd-gusextreme= [HW,ALSA]
  1194. snd-gusmax= [HW,ALSA]
  1195. snd-hdsp= [HW,ALSA]
  1196. snd-ice1712= [HW,ALSA]
  1197. snd-intel8x0= [HW,ALSA]
  1198. snd-interwave= [HW,ALSA]
  1199. snd-interwave-stb=
  1200. [HW,ALSA]
  1201. snd-korg1212= [HW,ALSA]
  1202. snd-maestro3= [HW,ALSA]
  1203. snd-mpu401= [HW,ALSA]
  1204. snd-mtpav= [HW,ALSA]
  1205. snd-nm256= [HW,ALSA]
  1206. snd-opl3sa2= [HW,ALSA]
  1207. snd-opti92x-ad1848=
  1208. [HW,ALSA]
  1209. snd-opti92x-cs4231=
  1210. [HW,ALSA]
  1211. snd-opti93x= [HW,ALSA]
  1212. snd-pmac= [HW,ALSA]
  1213. snd-rme32= [HW,ALSA]
  1214. snd-rme96= [HW,ALSA]
  1215. snd-rme9652= [HW,ALSA]
  1216. snd-sb8= [HW,ALSA]
  1217. snd-sb16= [HW,ALSA]
  1218. snd-sbawe= [HW,ALSA]
  1219. snd-serial= [HW,ALSA]
  1220. snd-sgalaxy= [HW,ALSA]
  1221. snd-sonicvibes= [HW,ALSA]
  1222. snd-sun-amd7930=
  1223. [HW,ALSA]
  1224. snd-sun-cs4231= [HW,ALSA]
  1225. snd-trident= [HW,ALSA]
  1226. snd-usb-audio= [HW,ALSA,USB]
  1227. snd-via82xx= [HW,ALSA]
  1228. snd-virmidi= [HW,ALSA]
  1229. snd-wavefront= [HW,ALSA]
  1230. snd-ymfpci= [HW,ALSA]
  1231. sonycd535= [HW,CD]
  1232. Format: <io>[,<irq>]
  1233. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1234. See Documentation/sonypi.txt
  1235. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1236. See Documentation/specialix.txt.
  1237. spia_io_base= [HW,MTD]
  1238. spia_fio_base=
  1239. spia_pedr=
  1240. spia_peddr=
  1241. sscape= [HW,OSS]
  1242. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1243. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1244. See Documentation/scsi/st.txt.
  1245. st0x= [HW,SCSI]
  1246. See header of drivers/scsi/seagate.c.
  1247. sti= [PARISC,HW]
  1248. Format: <num>
  1249. Set the STI (builtin display/keyboard on the HP-PARISC
  1250. machines) console (graphic card) which should be used
  1251. as the initial boot-console.
  1252. See also comment in drivers/video/console/sticore.c.
  1253. sti_font= [HW]
  1254. See comment in drivers/video/console/sticore.c.
  1255. stifb= [HW]
  1256. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1257. swiotlb= [IA-64] Number of I/O TLB slabs
  1258. switches= [HW,M68k]
  1259. sym53c416= [HW,SCSI]
  1260. See header of drivers/scsi/sym53c416.c.
  1261. sysrq_always_enabled
  1262. [KNL]
  1263. Ignore sysrq setting - this boot parameter will
  1264. neutralize any effect of /proc/sys/kernel/sysrq.
  1265. Useful for debugging.
  1266. t128= [HW,SCSI]
  1267. See header of drivers/scsi/t128.c.
  1268. tdfx= [HW,DRM]
  1269. thash_entries= [KNL,NET]
  1270. Set number of hash buckets for TCP connection
  1271. time Show timing data prefixed to each printk message line
  1272. clocksource= [GENERIC_TIME] Override the default clocksource
  1273. Override the default clocksource and use the clocksource
  1274. with the name specified.
  1275. tipar.timeout= [HW,PPT]
  1276. Set communications timeout in tenths of a second
  1277. (default 15).
  1278. tipar.delay= [HW,PPT]
  1279. Set inter-bit delay in microseconds (default 10).
  1280. tmc8xx= [HW,SCSI]
  1281. See header of drivers/scsi/seagate.c.
  1282. tmscsim= [HW,SCSI]
  1283. See comment before function dc390_setup() in
  1284. drivers/scsi/tmscsim.c.
  1285. tp720= [HW,PS2]
  1286. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1287. Format:
  1288. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1289. tsdev.xres= [TS] Horizontal screen resolution.
  1290. tsdev.yres= [TS] Vertical screen resolution.
  1291. turbografx.map[2|3]= [HW,JOY]
  1292. TurboGraFX parallel port interface
  1293. Format:
  1294. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1295. See also Documentation/input/joystick-parport.txt
  1296. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1297. See header of drivers/scsi/u14-34f.c.
  1298. uart401= [HW,OSS]
  1299. Format: <io>,<irq>
  1300. uart6850= [HW,OSS]
  1301. Format: <io>,<irq>
  1302. uhci-hcd.ignore_oc=
  1303. [USB] Ignore overcurrent events (default N).
  1304. Some badly-designed motherboards generate lots of
  1305. bogus events, for ports that aren't wired to
  1306. anything. Set this parameter to avoid log spamming.
  1307. Note that genuine overcurrent events won't be
  1308. reported either.
  1309. usbcore.autosuspend=
  1310. [USB] The autosuspend time delay (in seconds) used
  1311. for newly-detected USB devices (default 2). This
  1312. is the time required before an idle device will be
  1313. autosuspended. Devices for which the delay is set
  1314. to 0 won't be autosuspended at all.
  1315. usbhid.mousepoll=
  1316. [USBHID] The interval which mice are to be polled at.
  1317. vdso= [IA-32]
  1318. vdso=1: enable VDSO (default)
  1319. vdso=0: disable VDSO mapping
  1320. video= [FB] Frame buffer configuration
  1321. See Documentation/fb/modedb.txt.
  1322. vga= [BOOT,IA-32] Select a particular video mode
  1323. See Documentation/i386/boot.txt and
  1324. Documentation/svga.txt.
  1325. Use vga=ask for menu.
  1326. This is actually a boot loader parameter; the value is
  1327. passed to the kernel using a special protocol.
  1328. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1329. size of <nn>. This can be used to increase the
  1330. minimum size (128MB on x86). It can also be used to
  1331. decrease the size and leave more room for directly
  1332. mapped kernel RAM.
  1333. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1334. Format: <command>
  1335. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1336. Format: <command>
  1337. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1338. Format: <command>
  1339. waveartist= [HW,OSS]
  1340. Format: <io>,<irq>,<dma>,<dma2>
  1341. wd33c93= [HW,SCSI]
  1342. See header of drivers/scsi/wd33c93.c.
  1343. wd7000= [HW,SCSI]
  1344. See header of drivers/scsi/wd7000.c.
  1345. wdt= [WDT] Watchdog
  1346. See Documentation/watchdog/watchdog.txt.
  1347. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1348. xd_geo= See header of drivers/block/xd.c.
  1349. xirc2ps_cs= [NET,PCMCIA]
  1350. Format:
  1351. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1352. norandmaps Don't use address space randomization
  1353. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1354. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1355. This is useful to get more information why
  1356. you got a "dwarf2 unwinder stuck"
  1357. ______________________________________________________________________
  1358. TODO:
  1359. Add documentation for ALSA options.
  1360. Add more DRM drivers.