kernel-parameters.txt 66 KB

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  1. Kernel Parameters
  2. ~~~~~~~~~~~~~~~~~
  3. The following is a consolidated list of the kernel parameters as implemented
  4. (mostly) by the __setup() macro and sorted into English Dictionary order
  5. (defined as ignoring all punctuation and sorting digits before letters in a
  6. case insensitive manner), and with descriptions where known.
  7. Module parameters for loadable modules are specified only as the
  8. parameter name with optional '=' and value as appropriate, such as:
  9. modprobe usbcore blinkenlights=1
  10. Module parameters for modules that are built into the kernel image
  11. are specified on the kernel command line with the module name plus
  12. '.' plus parameter name, with '=' and value if appropriate, such as:
  13. usbcore.blinkenlights=1
  14. This document may not be entirely up to date and comprehensive. The command
  15. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  16. module. Loadable modules, after being loaded into the running kernel, also
  17. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  18. parameters may be changed at runtime by the command
  19. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  20. The parameters listed below are only valid if certain kernel build options were
  21. enabled and if respective hardware is present. The text in square brackets at
  22. the beginning of each description states the restrictions within which a
  23. parameter is applicable:
  24. ACPI ACPI support is enabled.
  25. AGP AGP (Accelerated Graphics Port) is enabled.
  26. ALSA ALSA sound support is enabled.
  27. APIC APIC support is enabled.
  28. APM Advanced Power Management support is enabled.
  29. AVR32 AVR32 architecture is enabled.
  30. AX25 Appropriate AX.25 support is enabled.
  31. BLACKFIN Blackfin architecture is enabled.
  32. DRM Direct Rendering Management support is enabled.
  33. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  34. EFI EFI Partitioning (GPT) is enabled
  35. EIDE EIDE/ATAPI support is enabled.
  36. FB The frame buffer device is enabled.
  37. HW Appropriate hardware is enabled.
  38. IA-64 IA-64 architecture is enabled.
  39. IOSCHED More than one I/O scheduler is enabled.
  40. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  41. ISAPNP ISA PnP code is enabled.
  42. ISDN Appropriate ISDN support is enabled.
  43. JOY Appropriate joystick support is enabled.
  44. LIBATA Libata driver is enabled
  45. LP Printer support is enabled.
  46. LOOP Loopback device support is enabled.
  47. M68k M68k architecture is enabled.
  48. These options have more detailed description inside of
  49. Documentation/m68k/kernel-options.txt.
  50. MCA MCA bus support is enabled.
  51. MDA MDA console support is enabled.
  52. MOUSE Appropriate mouse support is enabled.
  53. MSI Message Signaled Interrupts (PCI).
  54. MTD MTD (Memory Technology Device) support is enabled.
  55. NET Appropriate network support is enabled.
  56. NUMA NUMA support is enabled.
  57. GENERIC_TIME The generic timeofday code is enabled.
  58. NFS Appropriate NFS support is enabled.
  59. OSS OSS sound support is enabled.
  60. PV_OPS A paravirtualized kernel is enabled.
  61. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  62. PARISC The PA-RISC architecture is enabled.
  63. PCI PCI bus support is enabled.
  64. PCIE PCI Express support is enabled.
  65. PCMCIA The PCMCIA subsystem is enabled.
  66. PNP Plug & Play support is enabled.
  67. PPC PowerPC architecture is enabled.
  68. PPT Parallel port support is enabled.
  69. PS2 Appropriate PS/2 support is enabled.
  70. RAM RAM disk support is enabled.
  71. ROOTPLUG The example Root Plug LSM is enabled.
  72. S390 S390 architecture is enabled.
  73. SCSI Appropriate SCSI support is enabled.
  74. A lot of drivers has their options described inside of
  75. Documentation/scsi/.
  76. SECURITY Different security models are enabled.
  77. SELINUX SELinux support is enabled.
  78. SERIAL Serial support is enabled.
  79. SH SuperH architecture is enabled.
  80. SMP The kernel is an SMP kernel.
  81. SPARC Sparc architecture is enabled.
  82. SWSUSP Software suspend is enabled.
  83. TS Appropriate touchscreen support is enabled.
  84. USB USB support is enabled.
  85. USBHID USB Human Interface Device support is enabled.
  86. V4L Video For Linux support is enabled.
  87. VGA The VGA console has been enabled.
  88. VT Virtual terminal support is enabled.
  89. WDT Watchdog support is enabled.
  90. XT IBM PC/XT MFM hard disk support is enabled.
  91. X86-32 X86-32, aka i386 architecture is enabled.
  92. X86-64 X86-64 architecture is enabled.
  93. More X86-64 boot options can be found in
  94. Documentation/x86_64/boot-options.txt .
  95. In addition, the following text indicates that the option:
  96. BUGS= Relates to possible processor bugs on the said processor.
  97. KNL Is a kernel start-up parameter.
  98. BOOT Is a boot loader parameter.
  99. Parameters denoted with BOOT are actually interpreted by the boot
  100. loader, and have no meaning to the kernel directly.
  101. Do not modify the syntax of boot loader parameters without extreme
  102. need or coordination with <Documentation/i386/boot.txt>.
  103. There are also arch-specific kernel-parameters not documented here.
  104. See for example <Documentation/x86_64/boot-options.txt>.
  105. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  106. a trailing = on the name of any parameter states that that parameter will
  107. be entered as an environment variable, whereas its absence indicates that
  108. it will appear as a kernel argument readable via /proc/cmdline by programs
  109. running once the system is up.
  110. The number of kernel parameters is not limited, but the length of the
  111. complete command line (parameters including spaces etc.) is limited to
  112. a fixed number of characters. This limit depends on the architecture
  113. and is between 256 and 4096 characters. It is defined in the file
  114. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  115. acpi= [HW,ACPI,X86-64,i386]
  116. Advanced Configuration and Power Interface
  117. Format: { force | off | ht | strict | noirq }
  118. force -- enable ACPI if default was off
  119. off -- disable ACPI if default was on
  120. noirq -- do not use ACPI for IRQ routing
  121. ht -- run only enough ACPI to enable Hyper Threading
  122. strict -- Be less tolerant of platforms that are not
  123. strictly ACPI specification compliant.
  124. See also Documentation/power/pm.txt, pci=noacpi
  125. acpi_apic_instance= [ACPI, IOAPIC]
  126. Format: <int>
  127. 2: use 2nd APIC table, if available
  128. 1,0: use 1st APIC table
  129. default: 0
  130. acpi_sleep= [HW,ACPI] Sleep options
  131. Format: { s3_bios, s3_mode, s3_beep }
  132. See Documentation/power/video.txt for s3_bios and s3_mode.
  133. s3_beep is for debugging; it makes the PC's speaker beep
  134. as soon as the kernel's real-mode entry point is called.
  135. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  136. Format: { level | edge | high | low }
  137. acpi_irq_balance [HW,ACPI]
  138. ACPI will balance active IRQs
  139. default in APIC mode
  140. acpi_irq_nobalance [HW,ACPI]
  141. ACPI will not move active IRQs (default)
  142. default in PIC mode
  143. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  144. use by PCI
  145. Format: <irq>,<irq>...
  146. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  147. Format: <irq>,<irq>...
  148. acpi_new_pts_ordering [HW,ACPI]
  149. Enforce the ACPI 2.0 ordering of the _PTS control
  150. method wrt putting devices into low power states
  151. default: pre ACPI 2.0 ordering of _PTS
  152. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  153. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  154. Format: To spoof as Windows 98: ="Microsoft Windows"
  155. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  156. acpi_osi="string1" # add string1 -- only one string
  157. acpi_osi="!string2" # remove built-in string2
  158. acpi_osi= # disable all strings
  159. acpi_serialize [HW,ACPI] force serialization of AML methods
  160. acpi_skip_timer_override [HW,ACPI]
  161. Recognize and ignore IRQ0/pin2 Interrupt Override.
  162. For broken nForce2 BIOS resulting in XT-PIC timer.
  163. acpi_use_timer_override [HW,ACPI}
  164. Use timer override. For some broken Nvidia NF5 boards
  165. that require a timer override, but don't have
  166. HPET
  167. acpi.debug_layer= [HW,ACPI]
  168. Format: <int>
  169. Each bit of the <int> indicates an ACPI debug layer,
  170. 1: enable, 0: disable. It is useful for boot time
  171. debugging. After system has booted up, it can be set
  172. via /sys/module/acpi/parameters/debug_layer.
  173. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  174. Available bits (add the numbers together) to enable debug output
  175. for specific parts of the ACPI subsystem:
  176. 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
  177. 0x10 namespace 0x20 parser 0x40 dispatcher
  178. 0x80 executer 0x100 resources 0x200 acpica debugger
  179. 0x400 os services 0x800 acpica disassembler.
  180. The number can be in decimal or prefixed with 0x in hex.
  181. Warning: Many of these options can produce a lot of
  182. output and make your system unusable. Be very careful.
  183. acpi.debug_level= [HW,ACPI]
  184. Format: <int>
  185. Each bit of the <int> indicates an ACPI debug level,
  186. 1: enable, 0: disable. It is useful for boot time
  187. debugging. After system has booted up, it can be set
  188. via /sys/module/acpi/parameters/debug_level.
  189. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  190. Available bits (add the numbers together) to enable different
  191. debug output levels of the ACPI subsystem:
  192. 0x01 error 0x02 warn 0x04 init 0x08 debug object
  193. 0x10 info 0x20 init names 0x40 parse 0x80 load
  194. 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
  195. 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
  196. 0x10000 resources 0x20000 user requests 0x40000 package.
  197. The number can be in decimal or prefixed with 0x in hex.
  198. Warning: Many of these options can produce a lot of
  199. output and make your system unusable. Be very careful.
  200. acpi_pm_good [X86-32,X86-64]
  201. Override the pmtimer bug detection: force the kernel
  202. to assume that this machine's pmtimer latches its value
  203. and always returns good values.
  204. agp= [AGP]
  205. { off | try_unsupported }
  206. off: disable AGP support
  207. try_unsupported: try to drive unsupported chipsets
  208. (may crash computer or cause data corruption)
  209. enable_timer_pin_1 [i386,x86-64]
  210. Enable PIN 1 of APIC timer
  211. Can be useful to work around chipset bugs
  212. (in particular on some ATI chipsets).
  213. The kernel tries to set a reasonable default.
  214. disable_timer_pin_1 [i386,x86-64]
  215. Disable PIN 1 of APIC timer
  216. Can be useful to work around chipset bugs.
  217. ad1848= [HW,OSS]
  218. Format: <io>,<irq>,<dma>,<dma2>,<type>
  219. advansys= [HW,SCSI]
  220. See header of drivers/scsi/advansys.c.
  221. advwdt= [HW,WDT] Advantech WDT
  222. Format: <iostart>,<iostop>
  223. aedsp16= [HW,OSS] Audio Excel DSP 16
  224. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  225. See also header of sound/oss/aedsp16.c.
  226. aha152x= [HW,SCSI]
  227. See Documentation/scsi/aha152x.txt.
  228. aha1542= [HW,SCSI]
  229. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  230. aic7xxx= [HW,SCSI]
  231. See Documentation/scsi/aic7xxx.txt.
  232. aic79xx= [HW,SCSI]
  233. See Documentation/scsi/aic79xx.txt.
  234. amijoy.map= [HW,JOY] Amiga joystick support
  235. Map of devices attached to JOY0DAT and JOY1DAT
  236. Format: <a>,<b>
  237. See also Documentation/kernel/input/joystick.txt
  238. analog.map= [HW,JOY] Analog joystick and gamepad support
  239. Specifies type or capabilities of an analog joystick
  240. connected to one of 16 gameports
  241. Format: <type1>,<type2>,..<type16>
  242. apc= [HW,SPARC]
  243. Power management functions (SPARCstation-4/5 + deriv.)
  244. Format: noidle
  245. Disable APC CPU standby support. SPARCstation-Fox does
  246. not play well with APC CPU idle - disable it if you have
  247. APC and your system crashes randomly.
  248. apic= [APIC,i386] Advanced Programmable Interrupt Controller
  249. Change the output verbosity whilst booting
  250. Format: { quiet (default) | verbose | debug }
  251. Change the amount of debugging information output
  252. when initialising the APIC and IO-APIC components.
  253. apm= [APM] Advanced Power Management
  254. See header of arch/i386/kernel/apm.c.
  255. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  256. Format: <io>,<irq>,<nodeID>
  257. ataflop= [HW,M68k]
  258. atarimouse= [HW,MOUSE] Atari Mouse
  259. atascsi= [HW,SCSI] Atari SCSI
  260. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  261. EzKey and similar keyboards
  262. atkbd.reset= [HW] Reset keyboard during initialization
  263. atkbd.set= [HW] Select keyboard code set
  264. Format: <int> (2 = AT (default), 3 = PS/2)
  265. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  266. keyboards
  267. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  268. Format: <bool> (0 = real, 1 = synthetic (default))
  269. atkbd.softrepeat= [HW]
  270. Use software keyboard repeat
  271. autotest [IA64]
  272. baycom_epp= [HW,AX25]
  273. Format: <io>,<mode>
  274. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  275. Format: <io>,<mode>
  276. See header of drivers/net/hamradio/baycom_par.c.
  277. baycom_ser_fdx= [HW,AX25]
  278. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  279. Format: <io>,<irq>,<mode>[,<baud>]
  280. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  281. baycom_ser_hdx= [HW,AX25]
  282. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  283. Format: <io>,<irq>,<mode>
  284. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  285. boot_delay= Milliseconds to delay each printk during boot.
  286. Values larger than 10 seconds (10000) are changed to
  287. no delay (0).
  288. Format: integer
  289. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  290. bttv.radio= Most important insmod options are available as
  291. kernel args too.
  292. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  293. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  294. BusLogic= [HW,SCSI]
  295. See drivers/scsi/BusLogic.c, comment before function
  296. BusLogic_ParseDriverOptions().
  297. c101= [NET] Moxa C101 synchronous serial card
  298. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  299. Sometimes CPU hardware bugs make them report the cache
  300. size incorrectly. The kernel will attempt work arounds
  301. to fix known problems, but for some CPUs it is not
  302. possible to determine what the correct size should be.
  303. This option provides an override for these situations.
  304. capability.disable=
  305. [SECURITY] Disable capabilities. This would normally
  306. be used only if an alternative security model is to be
  307. configured. Potentially dangerous and should only be
  308. used if you are entirely sure of the consequences.
  309. ccw_timeout_log [S390]
  310. See Documentation/s390/CommonIO for details.
  311. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  312. Format: { "0" | "1" }
  313. See security/selinux/Kconfig help text.
  314. 0 -- check protection applied by kernel (includes
  315. any implied execute protection).
  316. 1 -- check protection requested by application.
  317. Default value is set via a kernel config option.
  318. Value can be changed at runtime via
  319. /selinux/checkreqprot.
  320. cio_ignore= [S390]
  321. See Documentation/s390/CommonIO for details.
  322. cio_msg= [S390]
  323. See Documentation/s390/CommonIO for details.
  324. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  325. [Deprecated]
  326. Forces specified clocksource (if available) to be used
  327. when calculating gettimeofday(). If specified
  328. clocksource is not available, it defaults to PIT.
  329. Format: { pit | tsc | cyclone | pmtmr }
  330. clocksource= [GENERIC_TIME] Override the default clocksource
  331. Format: <string>
  332. Override the default clocksource and use the clocksource
  333. with the name specified.
  334. Some clocksource names to choose from, depending on
  335. the platform:
  336. [all] jiffies (this is the base, fallback clocksource)
  337. [ACPI] acpi_pm
  338. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  339. pxa_timer,timer3,32k_counter,timer0_1
  340. [AVR32] avr32
  341. [X86-32] pit,hpet,tsc,vmi-timer;
  342. scx200_hrt on Geode; cyclone on IBM x440
  343. [MIPS] MIPS
  344. [PARISC] cr16
  345. [S390] tod
  346. [SH] SuperH
  347. [SPARC64] tick
  348. [X86-64] hpet,tsc
  349. clearcpuid=BITNUM [X86]
  350. Disable CPUID feature X for the kernel. See
  351. include/asm-x86/cpufeature.h for the valid bit numbers.
  352. Note the Linux specific bits are not necessarily
  353. stable over kernel options, but the vendor specific
  354. ones should be.
  355. Also note that user programs calling CPUID directly
  356. or using the feature without checking anything
  357. will still see it. This just prevents it from
  358. being used by the kernel or shown in /proc/cpuinfo.
  359. Also note the kernel might malfunction if you disable
  360. some critical bits.
  361. code_bytes [IA32/X86_64] How many bytes of object code to print
  362. in an oops report.
  363. Range: 0 - 8192
  364. Default: 64
  365. disable_8254_timer
  366. enable_8254_timer
  367. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  368. over the 8254 in addition to over the IO-APIC. The
  369. kernel tries to set a sensible default.
  370. hpet= [X86-32,HPET] option to control HPET usage
  371. Format: { enable (default) | disable | force }
  372. disable: disable HPET and use PIT instead
  373. force: allow force enabled of undocumented chips (ICH4,
  374. VIA, nVidia)
  375. com20020= [HW,NET] ARCnet - COM20020 chipset
  376. Format:
  377. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  378. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  379. Format: <io>[,<irq>]
  380. com90xx= [HW,NET]
  381. ARCnet - COM90xx chipset (memory-mapped buffers)
  382. Format: <io>[,<irq>[,<memstart>]]
  383. condev= [HW,S390] console device
  384. conmode=
  385. console= [KNL] Output console device and options.
  386. tty<n> Use the virtual console device <n>.
  387. ttyS<n>[,options]
  388. ttyUSB0[,options]
  389. Use the specified serial port. The options are of
  390. the form "bbbbpnf", where "bbbb" is the baud rate,
  391. "p" is parity ("n", "o", or "e"), "n" is number of
  392. bits, and "f" is flow control ("r" for RTS or
  393. omit it). Default is "9600n8".
  394. See Documentation/serial-console.txt for more
  395. information. See
  396. Documentation/networking/netconsole.txt for an
  397. alternative.
  398. uart[8250],io,<addr>[,options]
  399. uart[8250],mmio,<addr>[,options]
  400. Start an early, polled-mode console on the 8250/16550
  401. UART at the specified I/O port or MMIO address,
  402. switching to the matching ttyS device later. The
  403. options are the same as for ttyS, above.
  404. earlycon= [KNL] Output early console device and options.
  405. uart[8250],io,<addr>[,options]
  406. uart[8250],mmio,<addr>[,options]
  407. Start an early, polled-mode console on the 8250/16550
  408. UART at the specified I/O port or MMIO address.
  409. The options are the same as for ttyS, above.
  410. no_console_suspend
  411. [HW] Never suspend the console
  412. Disable suspending of consoles during suspend and
  413. hibernate operations. Once disabled, debugging
  414. messages can reach various consoles while the rest
  415. of the system is being put to sleep (ie, while
  416. debugging driver suspend/resume hooks). This may
  417. not work reliably with all consoles, but is known
  418. to work with serial and VGA consoles.
  419. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  420. Format:
  421. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  422. crashkernel=nn[KMG]@ss[KMG]
  423. [KNL] Reserve a chunk of physical memory to
  424. hold a kernel to switch to with kexec on panic.
  425. crashkernel=range1:size1[,range2:size2,...][@offset]
  426. [KNL] Same as above, but depends on the memory
  427. in the running system. The syntax of range is
  428. start-[end] where start and end are both
  429. a memory unit (amount[KMG]). See also
  430. Documentation/kdump/kdump.txt for a example.
  431. cs4232= [HW,OSS]
  432. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  433. cs89x0_dma= [HW,NET]
  434. Format: <dma>
  435. cs89x0_media= [HW,NET]
  436. Format: { rj45 | aui | bnc }
  437. dasd= [HW,NET]
  438. See header of drivers/s390/block/dasd_devmap.c.
  439. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  440. (one device per port)
  441. Format: <port#>,<type>
  442. See also Documentation/input/joystick-parport.txt
  443. debug [KNL] Enable kernel debugging (events log level).
  444. debug_locks_verbose=
  445. [KNL] verbose self-tests
  446. Format=<0|1>
  447. Print debugging info while doing the locking API
  448. self-tests.
  449. We default to 0 (no extra messages), setting it to
  450. 1 will print _a lot_ more information - normally
  451. only useful to kernel developers.
  452. decnet.addr= [HW,NET]
  453. Format: <area>[,<node>]
  454. See also Documentation/networking/decnet.txt.
  455. vt.default_blu= [VT]
  456. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  457. Change the default blue palette of the console.
  458. This is a 16-member array composed of values
  459. ranging from 0-255.
  460. vt.default_grn= [VT]
  461. Format: <green0>,<green1>,<green2>,...,<green15>
  462. Change the default green palette of the console.
  463. This is a 16-member array composed of values
  464. ranging from 0-255.
  465. vt.default_red= [VT]
  466. Format: <red0>,<red1>,<red2>,...,<red15>
  467. Change the default red palette of the console.
  468. This is a 16-member array composed of values
  469. ranging from 0-255.
  470. vt.default_utf8=
  471. [VT]
  472. Format=<0|1>
  473. Set system-wide default UTF-8 mode for all tty's.
  474. Default is 1, i.e. UTF-8 mode is enabled for all
  475. newly opened terminals.
  476. dhash_entries= [KNL]
  477. Set number of hash buckets for dentry cache.
  478. digi= [HW,SERIAL]
  479. IO parameters + enable/disable command.
  480. digiepca= [HW,SERIAL]
  481. See drivers/char/README.epca and
  482. Documentation/digiepca.txt.
  483. disable_mtrr_trim [X86, Intel and AMD only]
  484. By default the kernel will trim any uncacheable
  485. memory out of your available memory pool based on
  486. MTRR settings. This parameter disables that behavior,
  487. possibly causing your machine to run very slowly.
  488. dmasound= [HW,OSS] Sound subsystem buffers
  489. dscc4.setup= [NET]
  490. dtc3181e= [HW,SCSI]
  491. earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
  492. earlyprintk=vga
  493. earlyprintk=serial[,ttySn[,baudrate]]
  494. Append ",keep" to not disable it when the real console
  495. takes over.
  496. Only vga or serial at a time, not both.
  497. Currently only ttyS0 and ttyS1 are supported.
  498. Interaction with the standard serial driver is not
  499. very good.
  500. The VGA output is eventually overwritten by the real
  501. console.
  502. eata= [HW,SCSI]
  503. edd= [EDD]
  504. Format: {"of[f]" | "sk[ipmbr]"}
  505. See comment in arch/i386/boot/edd.S
  506. eisa_irq_edge= [PARISC,HW]
  507. See header of drivers/parisc/eisa.c.
  508. elanfreq= [X86-32]
  509. See comment before function elanfreq_setup() in
  510. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  511. elevator= [IOSCHED]
  512. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  513. See Documentation/block/as-iosched.txt and
  514. Documentation/block/deadline-iosched.txt for details.
  515. elfcorehdr= [X86-32, X86_64]
  516. Specifies physical address of start of kernel core
  517. image elf header. Generally kexec loader will
  518. pass this option to capture kernel.
  519. See Documentation/kdump/kdump.txt for details.
  520. enforcing [SELINUX] Set initial enforcing status.
  521. Format: {"0" | "1"}
  522. See security/selinux/Kconfig help text.
  523. 0 -- permissive (log only, no denials).
  524. 1 -- enforcing (deny and log).
  525. Default value is 0.
  526. Value can be changed at runtime via /selinux/enforce.
  527. es1371= [HW,OSS]
  528. Format: <spdif>,[<nomix>,[<amplifier>]]
  529. See also header of sound/oss/es1371.c.
  530. ether= [HW,NET] Ethernet cards parameters
  531. This option is obsoleted by the "netdev=" option, which
  532. has equivalent usage. See its documentation for details.
  533. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  534. Format: <io>[,<irq>]
  535. failslab=
  536. fail_page_alloc=
  537. fail_make_request=[KNL]
  538. General fault injection mechanism.
  539. Format: <interval>,<probability>,<space>,<times>
  540. See also /Documentation/fault-injection/.
  541. fd_mcs= [HW,SCSI]
  542. See header of drivers/scsi/fd_mcs.c.
  543. fdomain= [HW,SCSI]
  544. See header of drivers/scsi/fdomain.c.
  545. floppy= [HW]
  546. See Documentation/floppy.txt.
  547. gamecon.map[2|3]=
  548. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  549. support via parallel port (up to 5 devices per port)
  550. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  551. See also Documentation/input/joystick-parport.txt
  552. gamma= [HW,DRM]
  553. gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
  554. Format: off | on
  555. default: on
  556. gdth= [HW,SCSI]
  557. See header of drivers/scsi/gdth.c.
  558. gpt [EFI] Forces disk with valid GPT signature but
  559. invalid Protective MBR to be treated as GPT.
  560. gvp11= [HW,SCSI]
  561. hashdist= [KNL,NUMA] Large hashes allocated during boot
  562. are distributed across NUMA nodes. Defaults on
  563. for IA-64, off otherwise.
  564. Format: 0 | 1 (for off | on)
  565. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  566. hd= [EIDE] (E)IDE hard drive subsystem geometry
  567. Format: <cyl>,<head>,<sect>
  568. hd?= [HW] (E)IDE subsystem
  569. hd?lun= See Documentation/ide/ide.txt.
  570. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  571. size of <nn>. This works even on boxes that have no
  572. highmem otherwise. This also works to reduce highmem
  573. size on bigger boxes.
  574. highres= [KNL] Enable/disable high resolution timer mode.
  575. Valid parameters: "on", "off"
  576. Default: "on"
  577. hisax= [HW,ISDN]
  578. See Documentation/isdn/README.HiSax.
  579. hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
  580. hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
  581. i8042.direct [HW] Put keyboard port into non-translated mode
  582. i8042.dumbkbd [HW] Pretend that controller can only read data from
  583. keyboard and cannot control its state
  584. (Don't attempt to blink the leds)
  585. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  586. i8042.nokbd [HW] Don't check/create keyboard port
  587. i8042.nomux [HW] Don't check presence of an active multiplexing
  588. controller
  589. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  590. controllers
  591. i8042.panicblink=
  592. [HW] Frequency with which keyboard LEDs should blink
  593. when kernel panics (default is 0.5 sec)
  594. i8042.reset [HW] Reset the controller during init and cleanup
  595. i8042.unlock [HW] Unlock (ignore) the keylock
  596. i810= [HW,DRM]
  597. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  598. indicates that the driver is running on unsupported
  599. hardware.
  600. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  601. does not match list of supported models.
  602. i8k.power_status
  603. [HW] Report power status in /proc/i8k
  604. (disabled by default)
  605. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  606. capability is set.
  607. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  608. See Documentation/mca.txt.
  609. icn= [HW,ISDN]
  610. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  611. ide= [HW] (E)IDE subsystem
  612. Format: ide=nodma or ide=doubler or ide=reverse
  613. See Documentation/ide/ide.txt.
  614. ide?= [HW] (E)IDE subsystem
  615. Format: ide?=noprobe or chipset specific parameters.
  616. See Documentation/ide/ide.txt.
  617. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  618. See Documentation/ide/ide.txt.
  619. idle= [X86]
  620. Format: idle=poll or idle=mwait
  621. Poll forces a polling idle loop that can slightly improves the performance
  622. of waking up a idle CPU, but will use a lot of power and make the system
  623. run hot. Not recommended.
  624. idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
  625. to not use it because it doesn't save as much power as a normal idle
  626. loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
  627. as idle=poll.
  628. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
  629. Claim all unknown PCI IDE storage controllers.
  630. ignore_loglevel [KNL]
  631. Ignore loglevel setting - this will print /all/
  632. kernel messages to the console. Useful for debugging.
  633. ihash_entries= [KNL]
  634. Set number of hash buckets for inode cache.
  635. in2000= [HW,SCSI]
  636. See header of drivers/scsi/in2000.c.
  637. init= [KNL]
  638. Format: <full_path>
  639. Run specified binary instead of /sbin/init as init
  640. process.
  641. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  642. for working out where the kernel is dying during
  643. startup.
  644. initrd= [BOOT] Specify the location of the initial ramdisk
  645. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  646. Format: <irq>
  647. inttest= [IA64]
  648. intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
  649. off
  650. Disable intel iommu driver.
  651. igfx_off [Default Off]
  652. By default, gfx is mapped as normal device. If a gfx
  653. device has a dedicated DMAR unit, the DMAR unit is
  654. bypassed by not enabling DMAR with this option. In
  655. this case, gfx device will use physical address for
  656. DMA.
  657. forcedac [x86_64]
  658. With this option iommu will not optimize to look
  659. for io virtual address below 32 bit forcing dual
  660. address cycle on pci bus for cards supporting greater
  661. than 32 bit addressing. The default is to look
  662. for translation below 32 bit and if not available
  663. then look in the higher range.
  664. io_delay= [X86-32,X86-64] I/O delay method
  665. 0x80
  666. Standard port 0x80 based delay
  667. 0xed
  668. Alternate port 0xed based delay (needed on some systems)
  669. udelay
  670. Simple two microseconds delay
  671. none
  672. No delay
  673. io7= [HW] IO7 for Marvel based alpha systems
  674. See comment before marvel_specify_io7 in
  675. arch/alpha/kernel/core_marvel.c.
  676. ip= [IP_PNP]
  677. See Documentation/nfsroot.txt.
  678. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  679. See comment before ip2_setup() in
  680. drivers/char/ip2/ip2base.c.
  681. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  682. See header of drivers/scsi/ips.c.
  683. ports= [IP_VS_FTP] IPVS ftp helper module
  684. Default is 21.
  685. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  686. may be specified.
  687. Format: <port>,<port>....
  688. irqfixup [HW]
  689. When an interrupt is not handled search all handlers
  690. for it. Intended to get systems with badly broken
  691. firmware running.
  692. irqpoll [HW]
  693. When an interrupt is not handled search all handlers
  694. for it. Also check all handlers each timer
  695. interrupt. Intended to get systems with badly broken
  696. firmware running.
  697. isapnp= [ISAPNP]
  698. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  699. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  700. Format:
  701. <cpu number>,...,<cpu number>
  702. or
  703. <cpu number>-<cpu number> (must be a positive range in ascending order)
  704. or a mixture
  705. <cpu number>,...,<cpu number>-<cpu number>
  706. This option can be used to specify one or more CPUs
  707. to isolate from the general SMP balancing and scheduling
  708. algorithms. The only way to move a process onto or off
  709. an "isolated" CPU is via the CPU affinity syscalls.
  710. <cpu number> begins at 0 and the maximum value is
  711. "number of CPUs in system - 1".
  712. This option is the preferred way to isolate CPUs. The
  713. alternative -- manually setting the CPU mask of all
  714. tasks in the system -- can cause problems and
  715. suboptimal load balancer performance.
  716. iucv= [HW,NET]
  717. js= [HW,JOY] Analog joystick
  718. See Documentation/input/joystick.txt.
  719. kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  720. specifies the amount of memory usable by the kernel
  721. for non-movable allocations. The requested amount is
  722. spread evenly throughout all nodes in the system. The
  723. remaining memory in each node is used for Movable
  724. pages. In the event, a node is too small to have both
  725. kernelcore and Movable pages, kernelcore pages will
  726. take priority and other nodes will have a larger number
  727. of kernelcore pages. The Movable zone is used for the
  728. allocation of pages that may be reclaimed or moved
  729. by the page migration subsystem. This means that
  730. HugeTLB pages may not be allocated from this zone.
  731. Note that allocations like PTEs-from-HighMem still
  732. use the HighMem zone if it exists, and the Normal
  733. zone if it does not.
  734. movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  735. is similar to kernelcore except it specifies the
  736. amount of memory used for migratable allocations.
  737. If both kernelcore and movablecore is specified,
  738. then kernelcore will be at *least* the specified
  739. value but may be more. If movablecore on its own
  740. is specified, the administrator must be careful
  741. that the amount of memory usable for all allocations
  742. is not too small.
  743. keepinitrd [HW,ARM]
  744. kstack=N [X86-32,X86-64] Print N words from the kernel stack
  745. in oops dumps.
  746. l2cr= [PPC]
  747. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  748. disabled it.
  749. lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
  750. C2 power state.
  751. libata.dma= [LIBATA] DMA control
  752. libata.dma=0 Disable all PATA and SATA DMA
  753. libata.dma=1 PATA and SATA Disk DMA only
  754. libata.dma=2 ATAPI (CDROM) DMA only
  755. libata.dma=4 Compact Flash DMA only
  756. Combinations also work, so libata.dma=3 enables DMA
  757. for disks and CDROMs, but not CFs.
  758. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  759. when set.
  760. Format: <int>
  761. libata.force= [LIBATA] Force configurations. The format is comma
  762. separated list of "[ID:]VAL" where ID is
  763. PORT[:DEVICE]. PORT and DEVICE are decimal numbers
  764. matching port, link or device. Basically, it matches
  765. the ATA ID string printed on console by libata. If
  766. the whole ID part is omitted, the last PORT and DEVICE
  767. values are used. If ID hasn't been specified yet, the
  768. configuration applies to all ports, links and devices.
  769. If only DEVICE is omitted, the parameter applies to
  770. the port and all links and devices behind it. DEVICE
  771. number of 0 either selects the first device or the
  772. first fan-out link behind PMP device. It does not
  773. select the host link. DEVICE number of 15 selects the
  774. host link and device attached to it.
  775. The VAL specifies the configuration to force. As long
  776. as there's no ambiguity shortcut notation is allowed.
  777. For example, both 1.5 and 1.5G would work for 1.5Gbps.
  778. The following configurations can be forced.
  779. * Cable type: 40c, 80c, short40c, unk, ign or sata.
  780. Any ID with matching PORT is used.
  781. * SATA link speed limit: 1.5Gbps or 3.0Gbps.
  782. * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
  783. udma[/][16,25,33,44,66,100,133] notation is also
  784. allowed.
  785. * [no]ncq: Turn on or off NCQ.
  786. If there are multiple matching configurations changing
  787. the same attribute, the last one is used.
  788. load_ramdisk= [RAM] List of ramdisks to load from floppy
  789. See Documentation/ramdisk.txt.
  790. lockd.nlm_grace_period=P [NFS] Assign grace period.
  791. Format: <integer>
  792. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  793. Format: <integer>
  794. lockd.nlm_timeout=T [NFS] Assign timeout value.
  795. Format: <integer>
  796. lockd.nlm_udpport=M [NFS] Assign UDP port.
  797. Format: <integer>
  798. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  799. Format: <irq>
  800. loglevel= All Kernel Messages with a loglevel smaller than the
  801. console loglevel will be printed to the console. It can
  802. also be changed with klogd or other programs. The
  803. loglevels are defined as follows:
  804. 0 (KERN_EMERG) system is unusable
  805. 1 (KERN_ALERT) action must be taken immediately
  806. 2 (KERN_CRIT) critical conditions
  807. 3 (KERN_ERR) error conditions
  808. 4 (KERN_WARNING) warning conditions
  809. 5 (KERN_NOTICE) normal but significant condition
  810. 6 (KERN_INFO) informational
  811. 7 (KERN_DEBUG) debug-level messages
  812. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  813. Format: { n | nk | nM }
  814. n must be a power of two. The default size
  815. is set in the kernel config file.
  816. logo.nologo [FB] Disables display of the built-in Linux logo.
  817. This may be used to provide more screen space for
  818. kernel log messages and is useful when debugging
  819. kernel boot problems.
  820. lp=0 [LP] Specify parallel ports to use, e.g,
  821. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  822. lp=reset first parallel port). 'lp=0' disables the
  823. lp=auto printer driver. 'lp=reset' (which can be
  824. specified in addition to the ports) causes
  825. attached printers to be reset. Using
  826. lp=port1,port2,... specifies the parallel ports
  827. to associate lp devices with, starting with
  828. lp0. A port specification may be 'none' to skip
  829. that lp device, or a parport name such as
  830. 'parport0'. Specifying 'lp=auto' instead of a
  831. port specification list means that device IDs
  832. from each port should be examined, to see if
  833. an IEEE 1284-compliant printer is attached; if
  834. so, the driver will manage that printer.
  835. See also header of drivers/char/lp.c.
  836. lpj=n [KNL]
  837. Sets loops_per_jiffy to given constant, thus avoiding
  838. time-consuming boot-time autodetection (up to 250 ms per
  839. CPU). 0 enables autodetection (default). To determine
  840. the correct value for your kernel, boot with normal
  841. autodetection and see what value is printed. Note that
  842. on SMP systems the preset will be applied to all CPUs,
  843. which is likely to cause problems if your CPUs need
  844. significantly divergent settings. An incorrect value
  845. will cause delays in the kernel to be wrong, leading to
  846. unpredictable I/O errors and other breakage. Although
  847. unlikely, in the extreme case this might damage your
  848. hardware.
  849. ltpc= [NET]
  850. Format: <io>,<irq>,<dma>
  851. mac5380= [HW,SCSI] Format:
  852. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  853. mac53c9x= [HW,SCSI] Format:
  854. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  855. machvec= [IA64] Force the use of a particular machine-vector
  856. (machvec) in a generic kernel.
  857. Example: machvec=hpzx1_swiotlb
  858. max_loop= [LOOP] Maximum number of loopback devices that can
  859. be mounted
  860. Format: <1-256>
  861. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  862. should make use of. maxcpus=n : n >= 0 limits the
  863. kernel to using 'n' processors. n=0 is a special case,
  864. it is equivalent to "nosmp", which also disables
  865. the IO APIC.
  866. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  867. equal to this physical address is ignored.
  868. max_luns= [SCSI] Maximum number of LUNs to probe.
  869. Should be between 1 and 2^32-1.
  870. max_report_luns=
  871. [SCSI] Maximum number of LUNs received.
  872. Should be between 1 and 16384.
  873. mcatest= [IA-64]
  874. mce [X86-32] Machine Check Exception
  875. mce=option [X86-64] See Documentation/x86_64/boot-options.txt
  876. md= [HW] RAID subsystems devices and level
  877. See Documentation/md.txt.
  878. mdacon= [MDA]
  879. Format: <first>,<last>
  880. Specifies range of consoles to be captured by the MDA.
  881. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  882. Amount of memory to be used when the kernel is not able
  883. to see the whole system memory or for test.
  884. [X86-32] Use together with memmap= to avoid physical
  885. address space collisions. Without memmap= PCI devices
  886. could be placed at addresses belonging to unused RAM.
  887. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  888. memory.
  889. memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
  890. E820 memory map, as specified by the user.
  891. Such memmap=exactmap lines can be constructed based on
  892. BIOS output or other requirements. See the memmap=nn@ss
  893. option description.
  894. memmap=nn[KMG]@ss[KMG]
  895. [KNL] Force usage of a specific region of memory
  896. Region of memory to be used, from ss to ss+nn.
  897. memmap=nn[KMG]#ss[KMG]
  898. [KNL,ACPI] Mark specific memory as ACPI data.
  899. Region of memory to be used, from ss to ss+nn.
  900. memmap=nn[KMG]$ss[KMG]
  901. [KNL,ACPI] Mark specific memory as reserved.
  902. Region of memory to be used, from ss to ss+nn.
  903. meye.*= [HW] Set MotionEye Camera parameters
  904. See Documentation/video4linux/meye.txt.
  905. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  906. Multi-Function General Purpose Timers on AMD Geode
  907. platforms.
  908. mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
  909. the BIOS has incorrectly applied a workaround. TinyBIOS
  910. version 0.98 is known to be affected, 0.99 fixes the
  911. problem by letting the user disable the workaround.
  912. mga= [HW,DRM]
  913. mousedev.tap_time=
  914. [MOUSE] Maximum time between finger touching and
  915. leaving touchpad surface for touch to be considered
  916. a tap and be reported as a left button click (for
  917. touchpads working in absolute mode only).
  918. Format: <msecs>
  919. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  920. reporting absolute coordinates, such as tablets
  921. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  922. reporting absolute coordinates, such as tablets
  923. mpu401= [HW,OSS]
  924. Format: <io>,<irq>
  925. MTD_Partition= [MTD]
  926. Format: <name>,<region-number>,<size>,<offset>
  927. MTD_Region= [MTD] Format:
  928. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  929. mtdparts= [MTD]
  930. See drivers/mtd/cmdlinepart.c.
  931. mtouchusb.raw_coordinates=
  932. [HW] Make the MicroTouch USB driver use raw coordinates
  933. ('y', default) or cooked coordinates ('n')
  934. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  935. NCR_D700= [HW,SCSI]
  936. See header of drivers/scsi/NCR_D700.c.
  937. ncr5380= [HW,SCSI]
  938. ncr53c400= [HW,SCSI]
  939. ncr53c400a= [HW,SCSI]
  940. ncr53c406a= [HW,SCSI]
  941. ncr53c8xx= [HW,SCSI]
  942. netdev= [NET] Network devices parameters
  943. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  944. Note that mem_start is often overloaded to mean
  945. something different and driver-specific.
  946. This usage is only documented in each driver source
  947. file if at all.
  948. nfsaddrs= [NFS]
  949. See Documentation/nfsroot.txt.
  950. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  951. See Documentation/nfsroot.txt.
  952. nfs.callback_tcpport=
  953. [NFS] set the TCP port on which the NFSv4 callback
  954. channel should listen.
  955. nfs.idmap_cache_timeout=
  956. [NFS] set the maximum lifetime for idmapper cache
  957. entries.
  958. nfs.enable_ino64=
  959. [NFS] enable 64-bit inode numbers.
  960. If zero, the NFS client will fake up a 32-bit inode
  961. number for the readdir() and stat() syscalls instead
  962. of returning the full 64-bit number.
  963. The default is to return 64-bit inode numbers.
  964. nmi_debug= [KNL,AVR32] Specify one or more actions to take
  965. when a NMI is triggered.
  966. Format: [state][,regs][,debounce][,die]
  967. nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
  968. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  969. emulation library even if a 387 maths coprocessor
  970. is present.
  971. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  972. caches in the slab allocator. Saves per-node memory,
  973. but will impact performance.
  974. noalign [KNL,ARM]
  975. noapic [SMP,APIC] Tells the kernel to not make use of any
  976. IOAPICs that may be present in the system.
  977. nobats [PPC] Do not use BATs for mapping kernel lowmem
  978. on "Classic" PPC cores.
  979. nocache [ARM]
  980. nodelayacct [KNL] Disable per-task delay accounting
  981. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  982. noefi [X86-32,X86-64] Disable EFI runtime services support.
  983. noexec [IA-64]
  984. noexec [X86-32,X86-64]
  985. noexec=on: enable non-executable mappings (default)
  986. noexec=off: disable nn-executable mappings
  987. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  988. register save and restore. The kernel will only save
  989. legacy floating-point registers on task switch.
  990. noclflush [BUGS=X86] Don't use the CLFLUSH instruction
  991. nohlt [BUGS=ARM]
  992. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  993. instruction doesn't work correctly and not to
  994. use it.
  995. nohalt [IA-64] Tells the kernel not to use the power saving
  996. function PAL_HALT_LIGHT when idle. This increases
  997. power-consumption. On the positive side, it reduces
  998. interrupt wake-up latency, which may improve performance
  999. in certain environments such as networked servers or
  1000. real-time systems.
  1001. nohz= [KNL] Boottime enable/disable dynamic ticks
  1002. Valid arguments: on, off
  1003. Default: on
  1004. noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
  1005. noirqdebug [X86-32] Disables the code which attempts to detect and
  1006. disable unhandled interrupt sources.
  1007. no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
  1008. broken timer IRQ sources.
  1009. noisapnp [ISAPNP] Disables ISA PnP code.
  1010. noinitrd [RAM] Tells the kernel not to load any configured
  1011. initial RAM disk.
  1012. nointroute [IA-64]
  1013. nojitter [IA64] Disables jitter checking for ITC timers.
  1014. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  1015. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  1016. noltlbs [PPC] Do not use large page/tlb entries for kernel
  1017. lowmem mapping on PPC40x.
  1018. nomca [IA-64] Disable machine check abort handling
  1019. nomce [X86-32] Machine Check Exception
  1020. nomfgpt [X86-32] Disable Multi-Function General Purpose
  1021. Timer usage (for AMD Geode machines).
  1022. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  1023. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  1024. with UP alternatives
  1025. noresidual [PPC] Don't use residual data on PReP machines.
  1026. noresume [SWSUSP] Disables resume and restores original swap
  1027. space.
  1028. no-scroll [VGA] Disables scrollback.
  1029. This is required for the Braillex ib80-piezo Braille
  1030. reader made by F.H. Papenmeier (Germany).
  1031. nosbagart [IA-64]
  1032. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  1033. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  1034. and disable the IO APIC. legacy for "maxcpus=0".
  1035. nosoftlockup [KNL] Disable the soft-lockup detector.
  1036. nosync [HW,M68K] Disables sync negotiation for all devices.
  1037. notsc [BUGS=X86-32] Disable Time Stamp Counter
  1038. nousb [USB] Disable the USB subsystem
  1039. nowb [ARM]
  1040. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  1041. one of ['zone', 'node', 'default'] can be specified
  1042. This can be set from sysctl after boot.
  1043. See Documentation/sysctl/vm.txt for details.
  1044. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  1045. opl3= [HW,OSS]
  1046. Format: <io>
  1047. oprofile.timer= [HW]
  1048. Use timer interrupt instead of performance counters
  1049. osst= [HW,SCSI] SCSI Tape Driver
  1050. Format: <buffer_size>,<write_threshold>
  1051. See also Documentation/scsi/st.txt.
  1052. panic= [KNL] Kernel behaviour on panic
  1053. Format: <timeout>
  1054. parkbd.port= [HW] Parallel port number the keyboard adapter is
  1055. connected to, default is 0.
  1056. Format: <parport#>
  1057. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  1058. 0 for XT, 1 for AT (default is AT).
  1059. Format: <mode>
  1060. parport= [HW,PPT] Specify parallel ports. 0 disables.
  1061. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  1062. Use 'auto' to force the driver to use any
  1063. IRQ/DMA settings detected (the default is to
  1064. ignore detected IRQ/DMA settings because of
  1065. possible conflicts). You can specify the base
  1066. address, IRQ, and DMA settings; IRQ and DMA
  1067. should be numbers, or 'auto' (for using detected
  1068. settings on that particular port), or 'nofifo'
  1069. (to avoid using a FIFO even if it is detected).
  1070. Parallel ports are assigned in the order they
  1071. are specified on the command line, starting
  1072. with parport0.
  1073. parport_init_mode= [HW,PPT]
  1074. Configure VIA parallel port to operate in
  1075. a specific mode. This is necessary on Pegasos
  1076. computer where firmware has no options for setting
  1077. up parallel port mode and sets it to spp.
  1078. Currently this function knows 686a and 8231 chips.
  1079. Format: [spp|ps2|epp|ecp|ecpepp]
  1080. pas2= [HW,OSS] Format:
  1081. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  1082. pas16= [HW,SCSI]
  1083. See header of drivers/scsi/pas16.c.
  1084. pause_on_oops=
  1085. Halt all CPUs after the first oops has been printed for
  1086. the specified number of seconds. This is to be used if
  1087. your oopses keep scrolling off the screen.
  1088. pcbit= [HW,ISDN]
  1089. pcd. [PARIDE]
  1090. See header of drivers/block/paride/pcd.c.
  1091. See also Documentation/paride.txt.
  1092. pci=option[,option...] [PCI] various PCI subsystem options:
  1093. off [X86-32] don't probe for the PCI bus
  1094. bios [X86-32] force use of PCI BIOS, don't access
  1095. the hardware directly. Use this if your machine
  1096. has a non-standard PCI host bridge.
  1097. nobios [X86-32] disallow use of PCI BIOS, only direct
  1098. hardware access methods are allowed. Use this
  1099. if you experience crashes upon bootup and you
  1100. suspect they are caused by the BIOS.
  1101. conf1 [X86-32] Force use of PCI Configuration
  1102. Mechanism 1.
  1103. conf2 [X86-32] Force use of PCI Configuration
  1104. Mechanism 2.
  1105. noaer [PCIE] If the PCIEAER kernel config parameter is
  1106. enabled, this kernel boot option can be used to
  1107. disable the use of PCIE advanced error reporting.
  1108. nodomains [PCI] Disable support for multiple PCI
  1109. root domains (aka PCI segments, in ACPI-speak).
  1110. nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
  1111. Configuration
  1112. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1113. enabled, this kernel boot option can be used to
  1114. disable the use of MSI interrupts system-wide.
  1115. nosort [X86-32] Don't sort PCI devices according to
  1116. order given by the PCI BIOS. This sorting is
  1117. done to get a device order compatible with
  1118. older kernels.
  1119. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1120. routing table. These calls are known to be buggy
  1121. on several machines and they hang the machine
  1122. when used, but on other computers it's the only
  1123. way to get the interrupt routing table. Try
  1124. this option if the kernel is unable to allocate
  1125. IRQs or discover secondary PCI buses on your
  1126. motherboard.
  1127. rom [X86-32] Assign address space to expansion ROMs.
  1128. Use with caution as certain devices share
  1129. address decoders between ROMs and other
  1130. resources.
  1131. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
  1132. assigned automatically to PCI devices. You can
  1133. make the kernel exclude IRQs of your ISA cards
  1134. this way.
  1135. pirqaddr=0xAAAAA [X86-32] Specify the physical address
  1136. of the PIRQ table (normally generated
  1137. by the BIOS) if it is outside the
  1138. F0000h-100000h range.
  1139. lastbus=N [X86-32] Scan all buses thru bus #N. Can be
  1140. useful if the kernel is unable to find your
  1141. secondary buses and you want to tell it
  1142. explicitly which ones they are.
  1143. assign-busses [X86-32] Always assign all PCI bus
  1144. numbers ourselves, overriding
  1145. whatever the firmware may have done.
  1146. usepirqmask [X86-32] Honor the possible IRQ mask stored
  1147. in the BIOS $PIR table. This is needed on
  1148. some systems with broken BIOSes, notably
  1149. some HP Pavilion N5400 and Omnibook XE3
  1150. notebooks. This will have no effect if ACPI
  1151. IRQ routing is enabled.
  1152. noacpi [X86-32] Do not use ACPI for IRQ routing
  1153. or for PCI scanning.
  1154. use_crs [X86-32] Use _CRS for PCI resource
  1155. allocation.
  1156. routeirq Do IRQ routing for all PCI devices.
  1157. This is normally done in pci_enable_device(),
  1158. so this option is a temporary workaround
  1159. for broken drivers that don't call it.
  1160. firmware [ARM] Do not re-enumerate the bus but instead
  1161. just use the configuration from the
  1162. bootloader. This is currently used on
  1163. IXP2000 systems where the bus has to be
  1164. configured a certain way for adjunct CPUs.
  1165. noearly [X86] Don't do any early type 1 scanning.
  1166. This might help on some broken boards which
  1167. machine check when some devices' config space
  1168. is read. But various workarounds are disabled
  1169. and some IOMMU drivers will not work.
  1170. bfsort Sort PCI devices into breadth-first order.
  1171. This sorting is done to get a device
  1172. order compatible with older (<= 2.4) kernels.
  1173. nobfsort Don't sort PCI devices into breadth-first order.
  1174. cbiosize=nn[KMG] The fixed amount of bus space which is
  1175. reserved for the CardBus bridge's IO window.
  1176. The default value is 256 bytes.
  1177. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1178. reserved for the CardBus bridge's memory
  1179. window. The default value is 64 megabytes.
  1180. pcmv= [HW,PCMCIA] BadgePAD 4
  1181. pd. [PARIDE]
  1182. See Documentation/paride.txt.
  1183. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1184. boot time.
  1185. Format: { 0 | 1 }
  1186. See arch/parisc/kernel/pdc_chassis.c
  1187. pf. [PARIDE]
  1188. See Documentation/paride.txt.
  1189. pg. [PARIDE]
  1190. See Documentation/paride.txt.
  1191. pirq= [SMP,APIC] Manual mp-table setup
  1192. See Documentation/i386/IO-APIC.txt.
  1193. plip= [PPT,NET] Parallel port network link
  1194. Format: { parport<nr> | timid | 0 }
  1195. See also Documentation/parport.txt.
  1196. pnpacpi= [ACPI]
  1197. { off }
  1198. pnpbios= [ISAPNP]
  1199. { on | off | curr | res | no-curr | no-res }
  1200. pnp_reserve_irq=
  1201. [ISAPNP] Exclude IRQs for the autoconfiguration
  1202. pnp_reserve_dma=
  1203. [ISAPNP] Exclude DMAs for the autoconfiguration
  1204. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1205. Ranges are in pairs (I/O port base and size).
  1206. pnp_reserve_mem=
  1207. [ISAPNP] Exclude memory regions for the
  1208. autoconfiguration.
  1209. Ranges are in pairs (memory base and size).
  1210. print-fatal-signals=
  1211. [KNL] debug: print fatal signals
  1212. print-fatal-signals=1: print segfault info to
  1213. the kernel console.
  1214. default: off.
  1215. printk.time= Show timing data prefixed to each printk message line
  1216. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1217. profile= [KNL] Enable kernel profiling via /proc/profile
  1218. Format: [schedule,]<number>
  1219. Param: "schedule" - profile schedule points.
  1220. Param: <number> - step/bucket size as a power of 2 for
  1221. statistical time based profiling.
  1222. Param: "sleep" - profile D-state sleeping (millisecs).
  1223. Requires CONFIG_SCHEDSTATS
  1224. Param: "kvm" - profile VM exits.
  1225. processor.max_cstate= [HW,ACPI]
  1226. Limit processor to maximum C-state
  1227. max_cstate=9 overrides any DMI blacklist limit.
  1228. processor.nocst [HW,ACPI]
  1229. Ignore the _CST method to determine C-states,
  1230. instead using the legacy FADT method
  1231. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1232. before loading.
  1233. See Documentation/ramdisk.txt.
  1234. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1235. probe for; one of (bare|imps|exps|lifebook|any).
  1236. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1237. per second.
  1238. psmouse.resetafter= [HW,MOUSE]
  1239. Try to reset the device after so many bad packets
  1240. (0 = never).
  1241. psmouse.resolution=
  1242. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1243. psmouse.smartscroll=
  1244. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1245. 0 = disabled, 1 = enabled (default).
  1246. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1247. Format:
  1248. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1249. pt. [PARIDE]
  1250. See Documentation/paride.txt.
  1251. pty.legacy_count=
  1252. [KNL] Number of legacy pty's. Overwrites compiled-in
  1253. default number.
  1254. quiet [KNL] Disable most log messages
  1255. r128= [HW,DRM]
  1256. raid= [HW,RAID]
  1257. See Documentation/md.txt.
  1258. ramdisk_blocksize= [RAM]
  1259. See Documentation/ramdisk.txt.
  1260. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1261. See Documentation/ramdisk.txt.
  1262. rcupdate.blimit= [KNL,BOOT]
  1263. Set maximum number of finished RCU callbacks to process
  1264. in one batch.
  1265. rcupdate.qhimark= [KNL,BOOT]
  1266. Set threshold of queued
  1267. RCU callbacks over which batch limiting is disabled.
  1268. rcupdate.qlowmark= [KNL,BOOT]
  1269. Set threshold of queued RCU callbacks below which
  1270. batch limiting is re-enabled.
  1271. rdinit= [KNL]
  1272. Format: <full_path>
  1273. Run specified binary instead of /init from the ramdisk,
  1274. used for early userspace startup. See initrd.
  1275. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1276. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1277. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1278. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1279. reservetop= [X86-32]
  1280. Format: nn[KMG]
  1281. Reserves a hole at the top of the kernel virtual
  1282. address space.
  1283. reset_devices [KNL] Force drivers to reset the underlying device
  1284. during initialization.
  1285. resume= [SWSUSP]
  1286. Specify the partition device for software suspend
  1287. resume_offset= [SWSUSP]
  1288. Specify the offset from the beginning of the partition
  1289. given by "resume=" at which the swap header is located,
  1290. in <PAGE_SIZE> units (needed only for swap files).
  1291. See Documentation/power/swsusp-and-swap-files.txt
  1292. retain_initrd [RAM] Keep initrd memory after extraction
  1293. rhash_entries= [KNL,NET]
  1294. Set number of hash buckets for route cache
  1295. riscom8= [HW,SERIAL]
  1296. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1297. ro [KNL] Mount root device read-only on boot
  1298. root= [KNL] Root filesystem
  1299. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1300. mount the root filesystem
  1301. rootflags= [KNL] Set root filesystem mount option string
  1302. rootfstype= [KNL] Set root filesystem type
  1303. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1304. Useful for devices that are detected asynchronously
  1305. (e.g. USB and MMC devices).
  1306. root_plug.vendor_id=
  1307. [ROOTPLUG] Override the default vendor ID
  1308. root_plug.product_id=
  1309. [ROOTPLUG] Override the default product ID
  1310. root_plug.debug=
  1311. [ROOTPLUG] Enable debugging output
  1312. rw [KNL] Mount root device read-write on boot
  1313. S [KNL] Run init in single mode
  1314. sa1100ir [NET]
  1315. See drivers/net/irda/sa1100_ir.c.
  1316. sbni= [NET] Granch SBNI12 leased line adapter
  1317. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1318. Format: <io>[,<timeout>[,<isapnp>]]
  1319. scsi_debug_*= [SCSI]
  1320. See drivers/scsi/scsi_debug.c.
  1321. scsi_default_dev_flags=
  1322. [SCSI] SCSI default device flags
  1323. Format: <integer>
  1324. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1325. Format: <vendor>:<model>:<flags>
  1326. (flags are integer value)
  1327. scsi_logging_level= [SCSI] a bit mask of logging levels
  1328. See drivers/scsi/scsi_logging.h for bits. Also
  1329. settable via sysctl at dev.scsi.logging_level
  1330. (/proc/sys/dev/scsi/logging_level).
  1331. There is also a nice 'scsi_logging_level' script in the
  1332. S390-tools package, available for download at
  1333. http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
  1334. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1335. discovered. async scans them in kernel threads,
  1336. allowing boot to proceed. none ignores them, expecting
  1337. user space to do the scan.
  1338. selinux [SELINUX] Disable or enable SELinux at boot time.
  1339. Format: { "0" | "1" }
  1340. See security/selinux/Kconfig help text.
  1341. 0 -- disable.
  1342. 1 -- enable.
  1343. Default value is set via kernel config option.
  1344. If enabled at boot time, /selinux/disable can be used
  1345. later to disable prior to initial policy load.
  1346. selinux_compat_net =
  1347. [SELINUX] Set initial selinux_compat_net flag value.
  1348. Format: { "0" | "1" }
  1349. 0 -- use new secmark-based packet controls
  1350. 1 -- use legacy packet controls
  1351. Default value is 0 (preferred).
  1352. Value can be changed at runtime via
  1353. /selinux/compat_net.
  1354. serialnumber [BUGS=X86-32]
  1355. shapers= [NET]
  1356. Maximal number of shapers.
  1357. sim710= [SCSI,HW]
  1358. See header of drivers/scsi/sim710.c.
  1359. simeth= [IA-64]
  1360. simscsi=
  1361. slram= [HW,MTD]
  1362. slub_debug[=options[,slabs]] [MM, SLUB]
  1363. Enabling slub_debug allows one to determine the
  1364. culprit if slab objects become corrupted. Enabling
  1365. slub_debug can create guard zones around objects and
  1366. may poison objects when not in use. Also tracks the
  1367. last alloc / free. For more information see
  1368. Documentation/vm/slub.txt.
  1369. slub_max_order= [MM, SLUB]
  1370. Determines the maximum allowed order for slabs.
  1371. A high setting may cause OOMs due to memory
  1372. fragmentation. For more information see
  1373. Documentation/vm/slub.txt.
  1374. slub_min_objects= [MM, SLUB]
  1375. The minimum number of objects per slab. SLUB will
  1376. increase the slab order up to slub_max_order to
  1377. generate a sufficiently large slab able to contain
  1378. the number of objects indicated. The higher the number
  1379. of objects the smaller the overhead of tracking slabs
  1380. and the less frequently locks need to be acquired.
  1381. For more information see Documentation/vm/slub.txt.
  1382. slub_min_order= [MM, SLUB]
  1383. Determines the mininum page order for slabs. Must be
  1384. lower than slub_max_order.
  1385. For more information see Documentation/vm/slub.txt.
  1386. slub_nomerge [MM, SLUB]
  1387. Disable merging of slabs with similar size. May be
  1388. necessary if there is some reason to distinguish
  1389. allocs to different slabs. Debug options disable
  1390. merging on their own.
  1391. For more information see Documentation/vm/slub.txt.
  1392. smart2= [HW]
  1393. Format: <io1>[,<io2>[,...,<io8>]]
  1394. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1395. attempt to substitute SMP alternatives once at boot.
  1396. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1397. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1398. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1399. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1400. smsc-ircc2.ircc_irq= [HW] IRQ line
  1401. smsc-ircc2.ircc_dma= [HW] DMA channel
  1402. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1403. 0: Toshiba Satellite 1800 (GP data pin select)
  1404. 1: Fast pin select (default)
  1405. 2: ATC IRMode
  1406. snd-ad1816a= [HW,ALSA]
  1407. snd-ad1848= [HW,ALSA]
  1408. snd-ali5451= [HW,ALSA]
  1409. snd-als100= [HW,ALSA]
  1410. snd-als4000= [HW,ALSA]
  1411. snd-azt2320= [HW,ALSA]
  1412. snd-cmi8330= [HW,ALSA]
  1413. snd-cmipci= [HW,ALSA]
  1414. snd-cs4231= [HW,ALSA]
  1415. snd-cs4232= [HW,ALSA]
  1416. snd-cs4236= [HW,ALSA]
  1417. snd-cs4281= [HW,ALSA]
  1418. snd-cs46xx= [HW,ALSA]
  1419. snd-dt019x= [HW,ALSA]
  1420. snd-dummy= [HW,ALSA]
  1421. snd-emu10k1= [HW,ALSA]
  1422. snd-ens1370= [HW,ALSA]
  1423. snd-ens1371= [HW,ALSA]
  1424. snd-es968= [HW,ALSA]
  1425. snd-es1688= [HW,ALSA]
  1426. snd-es18xx= [HW,ALSA]
  1427. snd-es1938= [HW,ALSA]
  1428. snd-es1968= [HW,ALSA]
  1429. snd-fm801= [HW,ALSA]
  1430. snd-gusclassic= [HW,ALSA]
  1431. snd-gusextreme= [HW,ALSA]
  1432. snd-gusmax= [HW,ALSA]
  1433. snd-hdsp= [HW,ALSA]
  1434. snd-ice1712= [HW,ALSA]
  1435. snd-intel8x0= [HW,ALSA]
  1436. snd-interwave= [HW,ALSA]
  1437. snd-interwave-stb=
  1438. [HW,ALSA]
  1439. snd-korg1212= [HW,ALSA]
  1440. snd-maestro3= [HW,ALSA]
  1441. snd-mpu401= [HW,ALSA]
  1442. snd-mtpav= [HW,ALSA]
  1443. snd-nm256= [HW,ALSA]
  1444. snd-opl3sa2= [HW,ALSA]
  1445. snd-opti92x-ad1848=
  1446. [HW,ALSA]
  1447. snd-opti92x-cs4231=
  1448. [HW,ALSA]
  1449. snd-opti93x= [HW,ALSA]
  1450. snd-pmac= [HW,ALSA]
  1451. snd-rme32= [HW,ALSA]
  1452. snd-rme96= [HW,ALSA]
  1453. snd-rme9652= [HW,ALSA]
  1454. snd-sb8= [HW,ALSA]
  1455. snd-sb16= [HW,ALSA]
  1456. snd-sbawe= [HW,ALSA]
  1457. snd-serial= [HW,ALSA]
  1458. snd-sgalaxy= [HW,ALSA]
  1459. snd-sonicvibes= [HW,ALSA]
  1460. snd-sun-amd7930=
  1461. [HW,ALSA]
  1462. snd-sun-cs4231= [HW,ALSA]
  1463. snd-trident= [HW,ALSA]
  1464. snd-usb-audio= [HW,ALSA,USB]
  1465. snd-via82xx= [HW,ALSA]
  1466. snd-virmidi= [HW,ALSA]
  1467. snd-wavefront= [HW,ALSA]
  1468. snd-ymfpci= [HW,ALSA]
  1469. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1470. See Documentation/sonypi.txt
  1471. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1472. See Documentation/specialix.txt.
  1473. spia_io_base= [HW,MTD]
  1474. spia_fio_base=
  1475. spia_pedr=
  1476. spia_peddr=
  1477. sscape= [HW,OSS]
  1478. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1479. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1480. See Documentation/scsi/st.txt.
  1481. sti= [PARISC,HW]
  1482. Format: <num>
  1483. Set the STI (builtin display/keyboard on the HP-PARISC
  1484. machines) console (graphic card) which should be used
  1485. as the initial boot-console.
  1486. See also comment in drivers/video/console/sticore.c.
  1487. sti_font= [HW]
  1488. See comment in drivers/video/console/sticore.c.
  1489. stifb= [HW]
  1490. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1491. sunrpc.pool_mode=
  1492. [NFS]
  1493. Control how the NFS server code allocates CPUs to
  1494. service thread pools. Depending on how many NICs
  1495. you have and where their interrupts are bound, this
  1496. option will affect which CPUs will do NFS serving.
  1497. Note: this parameter cannot be changed while the
  1498. NFS server is running.
  1499. auto the server chooses an appropriate mode
  1500. automatically using heuristics
  1501. global a single global pool contains all CPUs
  1502. percpu one pool for each CPU
  1503. pernode one pool for each NUMA node (equivalent
  1504. to global on non-NUMA machines)
  1505. swiotlb= [IA-64] Number of I/O TLB slabs
  1506. switches= [HW,M68k]
  1507. sym53c416= [HW,SCSI]
  1508. See header of drivers/scsi/sym53c416.c.
  1509. sysrq_always_enabled
  1510. [KNL]
  1511. Ignore sysrq setting - this boot parameter will
  1512. neutralize any effect of /proc/sys/kernel/sysrq.
  1513. Useful for debugging.
  1514. t128= [HW,SCSI]
  1515. See header of drivers/scsi/t128.c.
  1516. tdfx= [HW,DRM]
  1517. thash_entries= [KNL,NET]
  1518. Set number of hash buckets for TCP connection
  1519. thermal.act= [HW,ACPI]
  1520. -1: disable all active trip points in all thermal zones
  1521. <degrees C>: override all lowest active trip points
  1522. thermal.crt= [HW,ACPI]
  1523. -1: disable all critical trip points in all thermal zones
  1524. <degrees C>: lower all critical trip points
  1525. thermal.nocrt= [HW,ACPI]
  1526. Set to disable actions on ACPI thermal zone
  1527. critical and hot trip points.
  1528. thermal.off= [HW,ACPI]
  1529. 1: disable ACPI thermal control
  1530. thermal.psv= [HW,ACPI]
  1531. -1: disable all passive trip points
  1532. <degrees C>: override all passive trip points to this value
  1533. thermal.tzp= [HW,ACPI]
  1534. Specify global default ACPI thermal zone polling rate
  1535. <deci-seconds>: poll all this frequency
  1536. 0: no polling (default)
  1537. tipar.timeout= [HW,PPT]
  1538. Set communications timeout in tenths of a second
  1539. (default 15).
  1540. tipar.delay= [HW,PPT]
  1541. Set inter-bit delay in microseconds (default 10).
  1542. tmscsim= [HW,SCSI]
  1543. See comment before function dc390_setup() in
  1544. drivers/scsi/tmscsim.c.
  1545. tp720= [HW,PS2]
  1546. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1547. Format:
  1548. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1549. turbografx.map[2|3]= [HW,JOY]
  1550. TurboGraFX parallel port interface
  1551. Format:
  1552. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1553. See also Documentation/input/joystick-parport.txt
  1554. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1555. See header of drivers/scsi/u14-34f.c.
  1556. uart401= [HW,OSS]
  1557. Format: <io>,<irq>
  1558. uart6850= [HW,OSS]
  1559. Format: <io>,<irq>
  1560. uhci-hcd.ignore_oc=
  1561. [USB] Ignore overcurrent events (default N).
  1562. Some badly-designed motherboards generate lots of
  1563. bogus events, for ports that aren't wired to
  1564. anything. Set this parameter to avoid log spamming.
  1565. Note that genuine overcurrent events won't be
  1566. reported either.
  1567. usbcore.autosuspend=
  1568. [USB] The autosuspend time delay (in seconds) used
  1569. for newly-detected USB devices (default 2). This
  1570. is the time required before an idle device will be
  1571. autosuspended. Devices for which the delay is set
  1572. to a negative value won't be autosuspended at all.
  1573. usbhid.mousepoll=
  1574. [USBHID] The interval which mice are to be polled at.
  1575. vdso= [X86-32,SH,x86-64]
  1576. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1577. vdso=1: enable VDSO (default)
  1578. vdso=0: disable VDSO mapping
  1579. vdso32= [X86-32,X86-64]
  1580. vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
  1581. vdso32=1: enable 32-bit VDSO (default)
  1582. vdso32=0: disable 32-bit VDSO mapping
  1583. vector= [IA-64,SMP]
  1584. vector=percpu: enable percpu vector domain
  1585. video= [FB] Frame buffer configuration
  1586. See Documentation/fb/modedb.txt.
  1587. vga= [BOOT,X86-32] Select a particular video mode
  1588. See Documentation/i386/boot.txt and
  1589. Documentation/svga.txt.
  1590. Use vga=ask for menu.
  1591. This is actually a boot loader parameter; the value is
  1592. passed to the kernel using a special protocol.
  1593. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1594. size of <nn>. This can be used to increase the
  1595. minimum size (128MB on x86). It can also be used to
  1596. decrease the size and leave more room for directly
  1597. mapped kernel RAM.
  1598. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1599. Format: <command>
  1600. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1601. Format: <command>
  1602. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1603. Format: <command>
  1604. waveartist= [HW,OSS]
  1605. Format: <io>,<irq>,<dma>,<dma2>
  1606. wd33c93= [HW,SCSI]
  1607. See header of drivers/scsi/wd33c93.c.
  1608. wd7000= [HW,SCSI]
  1609. See header of drivers/scsi/wd7000.c.
  1610. wdt= [WDT] Watchdog
  1611. See Documentation/watchdog/wdt.txt.
  1612. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1613. xd_geo= See header of drivers/block/xd.c.
  1614. xirc2ps_cs= [NET,PCMCIA]
  1615. Format:
  1616. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1617. norandmaps Don't use address space randomization
  1618. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1619. ______________________________________________________________________
  1620. TODO:
  1621. Add documentation for ALSA options.
  1622. Add more DRM drivers.