kernel-parameters.txt 61 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. AX25 Appropriate AX.25 support is enabled.
  30. BLACKFIN Blackfin architecture is enabled.
  31. DRM Direct Rendering Management support is enabled.
  32. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  33. EFI EFI Partitioning (GPT) is enabled
  34. EIDE EIDE/ATAPI support is enabled.
  35. FB The frame buffer device is enabled.
  36. HW Appropriate hardware is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LIBATA Libata driver is enabled
  44. LP Printer support is enabled.
  45. LOOP Loopback device support is enabled.
  46. M68k M68k architecture is enabled.
  47. These options have more detailed description inside of
  48. Documentation/m68k/kernel-options.txt.
  49. MCA MCA bus support is enabled.
  50. MDA MDA console support is enabled.
  51. MOUSE Appropriate mouse support is enabled.
  52. MSI Message Signaled Interrupts (PCI).
  53. MTD MTD (Memory Technology Device) support is enabled.
  54. NET Appropriate network support is enabled.
  55. NUMA NUMA support is enabled.
  56. GENERIC_TIME The generic timeofday code is enabled.
  57. NFS Appropriate NFS support is enabled.
  58. OSS OSS sound support is enabled.
  59. PV_OPS A paravirtualized kernel is enabled.
  60. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  61. PARISC The PA-RISC architecture is enabled.
  62. PCI PCI bus support is enabled.
  63. PCIE PCI Express support is enabled.
  64. PCMCIA The PCMCIA subsystem is enabled.
  65. PNP Plug & Play support is enabled.
  66. PPC PowerPC architecture is enabled.
  67. PPT Parallel port support is enabled.
  68. PS2 Appropriate PS/2 support is enabled.
  69. RAM RAM disk support is enabled.
  70. S390 S390 architecture is enabled.
  71. SCSI Appropriate SCSI support is enabled.
  72. A lot of drivers has their options described inside of
  73. Documentation/scsi/.
  74. SELINUX SELinux support is enabled.
  75. SERIAL Serial support is enabled.
  76. SH SuperH architecture is enabled.
  77. SMP The kernel is an SMP kernel.
  78. SPARC Sparc architecture is enabled.
  79. SWSUSP Software suspend is enabled.
  80. TS Appropriate touchscreen support is enabled.
  81. USB USB support is enabled.
  82. USBHID USB Human Interface Device support is enabled.
  83. V4L Video For Linux support is enabled.
  84. VGA The VGA console has been enabled.
  85. VT Virtual terminal support is enabled.
  86. WDT Watchdog support is enabled.
  87. XT IBM PC/XT MFM hard disk support is enabled.
  88. X86-32 X86-32, aka i386 architecture is enabled.
  89. X86-64 X86-64 architecture is enabled.
  90. More X86-64 boot options can be found in
  91. Documentation/x86_64/boot-options.txt .
  92. In addition, the following text indicates that the option:
  93. BUGS= Relates to possible processor bugs on the said processor.
  94. KNL Is a kernel start-up parameter.
  95. BOOT Is a boot loader parameter.
  96. Parameters denoted with BOOT are actually interpreted by the boot
  97. loader, and have no meaning to the kernel directly.
  98. Do not modify the syntax of boot loader parameters without extreme
  99. need or coordination with <Documentation/i386/boot.txt>.
  100. There are also arch-specific kernel-parameters not documented here.
  101. See for example <Documentation/x86_64/boot-options.txt>.
  102. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  103. a trailing = on the name of any parameter states that that parameter will
  104. be entered as an environment variable, whereas its absence indicates that
  105. it will appear as a kernel argument readable via /proc/cmdline by programs
  106. running once the system is up.
  107. The number of kernel parameters is not limited, but the length of the
  108. complete command line (parameters including spaces etc.) is limited to
  109. a fixed number of characters. This limit depends on the architecture
  110. and is between 256 and 4096 characters. It is defined in the file
  111. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  112. acpi= [HW,ACPI,X86-64,i386]
  113. Advanced Configuration and Power Interface
  114. Format: { force | off | ht | strict | noirq }
  115. force -- enable ACPI if default was off
  116. off -- disable ACPI if default was on
  117. noirq -- do not use ACPI for IRQ routing
  118. ht -- run only enough ACPI to enable Hyper Threading
  119. strict -- Be less tolerant of platforms that are not
  120. strictly ACPI specification compliant.
  121. See also Documentation/pm.txt, pci=noacpi
  122. acpi_apic_instance= [ACPI, IOAPIC]
  123. Format: <int>
  124. 2: use 2nd APIC table, if available
  125. 1,0: use 1st APIC table
  126. default: 0
  127. acpi_sleep= [HW,ACPI] Sleep options
  128. Format: { s3_bios, s3_mode }
  129. See Documentation/power/video.txt
  130. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  131. Format: { level | edge | high | low }
  132. acpi_irq_balance [HW,ACPI]
  133. ACPI will balance active IRQs
  134. default in APIC mode
  135. acpi_irq_nobalance [HW,ACPI]
  136. ACPI will not move active IRQs (default)
  137. default in PIC mode
  138. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  139. use by PCI
  140. Format: <irq>,<irq>...
  141. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  142. Format: <irq>,<irq>...
  143. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  144. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  145. Format: To spoof as Windows 98: ="Microsoft Windows"
  146. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  147. acpi_osi="string1" # add string1 -- only one string
  148. acpi_osi="!string2" # remove built-in string2
  149. acpi_osi= # disable all strings
  150. acpi_serialize [HW,ACPI] force serialization of AML methods
  151. acpi_skip_timer_override [HW,ACPI]
  152. Recognize and ignore IRQ0/pin2 Interrupt Override.
  153. For broken nForce2 BIOS resulting in XT-PIC timer.
  154. acpi_use_timer_override [HW,ACPI}
  155. Use timer override. For some broken Nvidia NF5 boards
  156. that require a timer override, but don't have
  157. HPET
  158. acpi.debug_layer= [HW,ACPI]
  159. Format: <int>
  160. Each bit of the <int> indicates an ACPI debug layer,
  161. 1: enable, 0: disable. It is useful for boot time
  162. debugging. After system has booted up, it can be set
  163. via /sys/module/acpi/parameters/debug_layer.
  164. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  165. Available bits (add the numbers together) to enable debug output
  166. for specific parts of the ACPI subsystem:
  167. 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
  168. 0x10 namespace 0x20 parser 0x40 dispatcher
  169. 0x80 executer 0x100 resources 0x200 acpica debugger
  170. 0x400 os services 0x800 acpica disassembler.
  171. The number can be in decimal or prefixed with 0x in hex.
  172. Warning: Many of these options can produce a lot of
  173. output and make your system unusable. Be very careful.
  174. acpi.debug_level= [HW,ACPI]
  175. Format: <int>
  176. Each bit of the <int> indicates an ACPI debug level,
  177. 1: enable, 0: disable. It is useful for boot time
  178. debugging. After system has booted up, it can be set
  179. via /sys/module/acpi/parameters/debug_level.
  180. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  181. Available bits (add the numbers together) to enable different
  182. debug output levels of the ACPI subsystem:
  183. 0x01 error 0x02 warn 0x04 init 0x08 debug object
  184. 0x10 info 0x20 init names 0x40 parse 0x80 load
  185. 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
  186. 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
  187. 0x10000 resources 0x20000 user requests 0x40000 package.
  188. The number can be in decimal or prefixed with 0x in hex.
  189. Warning: Many of these options can produce a lot of
  190. output and make your system unusable. Be very careful.
  191. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  192. acpi_pm_good [X86-32,X86-64]
  193. Override the pmtimer bug detection: force the kernel
  194. to assume that this machine's pmtimer latches its value
  195. and always returns good values.
  196. agp= [AGP]
  197. { off | try_unsupported }
  198. off: disable AGP support
  199. try_unsupported: try to drive unsupported chipsets
  200. (may crash computer or cause data corruption)
  201. enable_timer_pin_1 [i386,x86-64]
  202. Enable PIN 1 of APIC timer
  203. Can be useful to work around chipset bugs
  204. (in particular on some ATI chipsets).
  205. The kernel tries to set a reasonable default.
  206. disable_timer_pin_1 [i386,x86-64]
  207. Disable PIN 1 of APIC timer
  208. Can be useful to work around chipset bugs.
  209. ad1848= [HW,OSS]
  210. Format: <io>,<irq>,<dma>,<dma2>,<type>
  211. advansys= [HW,SCSI]
  212. See header of drivers/scsi/advansys.c.
  213. advwdt= [HW,WDT] Advantech WDT
  214. Format: <iostart>,<iostop>
  215. aedsp16= [HW,OSS] Audio Excel DSP 16
  216. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  217. See also header of sound/oss/aedsp16.c.
  218. aha152x= [HW,SCSI]
  219. See Documentation/scsi/aha152x.txt.
  220. aha1542= [HW,SCSI]
  221. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  222. aic7xxx= [HW,SCSI]
  223. See Documentation/scsi/aic7xxx.txt.
  224. aic79xx= [HW,SCSI]
  225. See Documentation/scsi/aic79xx.txt.
  226. amijoy.map= [HW,JOY] Amiga joystick support
  227. Map of devices attached to JOY0DAT and JOY1DAT
  228. Format: <a>,<b>
  229. See also Documentation/kernel/input/joystick.txt
  230. analog.map= [HW,JOY] Analog joystick and gamepad support
  231. Specifies type or capabilities of an analog joystick
  232. connected to one of 16 gameports
  233. Format: <type1>,<type2>,..<type16>
  234. apc= [HW,SPARC]
  235. Power management functions (SPARCstation-4/5 + deriv.)
  236. Format: noidle
  237. Disable APC CPU standby support. SPARCstation-Fox does
  238. not play well with APC CPU idle - disable it if you have
  239. APC and your system crashes randomly.
  240. apic= [APIC,i386] Advanced Programmable Interrupt Controller
  241. Change the output verbosity whilst booting
  242. Format: { quiet (default) | verbose | debug }
  243. Change the amount of debugging information output
  244. when initialising the APIC and IO-APIC components.
  245. apm= [APM] Advanced Power Management
  246. See header of arch/i386/kernel/apm.c.
  247. applicom= [HW]
  248. Format: <mem>,<irq>
  249. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  250. Format: <io>,<irq>,<nodeID>
  251. ataflop= [HW,M68k]
  252. atarimouse= [HW,MOUSE] Atari Mouse
  253. atascsi= [HW,SCSI] Atari SCSI
  254. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  255. EzKey and similar keyboards
  256. atkbd.reset= [HW] Reset keyboard during initialization
  257. atkbd.set= [HW] Select keyboard code set
  258. Format: <int> (2 = AT (default), 3 = PS/2)
  259. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  260. keyboards
  261. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  262. Format: <bool> (0 = real, 1 = synthetic (default))
  263. atkbd.softrepeat= [HW]
  264. Use software keyboard repeat
  265. autotest [IA64]
  266. baycom_epp= [HW,AX25]
  267. Format: <io>,<mode>
  268. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  269. Format: <io>,<mode>
  270. See header of drivers/net/hamradio/baycom_par.c.
  271. baycom_ser_fdx= [HW,AX25]
  272. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  273. Format: <io>,<irq>,<mode>[,<baud>]
  274. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  275. baycom_ser_hdx= [HW,AX25]
  276. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  277. Format: <io>,<irq>,<mode>
  278. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  279. blkmtd_device= [HW,MTD]
  280. blkmtd_erasesz=
  281. blkmtd_ro=
  282. blkmtd_bs=
  283. blkmtd_count=
  284. boot_delay= Milliseconds to delay each printk during boot.
  285. Values larger than 10 seconds (10000) are changed to
  286. no delay (0).
  287. Format: integer
  288. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  289. bttv.radio= Most important insmod options are available as
  290. kernel args too.
  291. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  292. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  293. BusLogic= [HW,SCSI]
  294. See drivers/scsi/BusLogic.c, comment before function
  295. BusLogic_ParseDriverOptions().
  296. c101= [NET] Moxa C101 synchronous serial card
  297. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  298. Sometimes CPU hardware bugs make them report the cache
  299. size incorrectly. The kernel will attempt work arounds
  300. to fix known problems, but for some CPUs it is not
  301. possible to determine what the correct size should be.
  302. This option provides an override for these situations.
  303. chandev= [HW,NET] Generic channel device initialisation
  304. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  305. Format: { "0" | "1" }
  306. See security/selinux/Kconfig help text.
  307. 0 -- check protection applied by kernel (includes
  308. any implied execute protection).
  309. 1 -- check protection requested by application.
  310. Default value is set via a kernel config option.
  311. Value can be changed at runtime via
  312. /selinux/checkreqprot.
  313. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  314. [Deprecated]
  315. Forces specified clocksource (if available) to be used
  316. when calculating gettimeofday(). If specified
  317. clocksource is not available, it defaults to PIT.
  318. Format: { pit | tsc | cyclone | pmtmr }
  319. clocksource= [GENERIC_TIME] Override the default clocksource
  320. Format: <string>
  321. Override the default clocksource and use the clocksource
  322. with the name specified.
  323. Some clocksource names to choose from, depending on
  324. the platform:
  325. [all] jiffies (this is the base, fallback clocksource)
  326. [ACPI] acpi_pm
  327. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  328. pxa_timer,timer3,32k_counter,timer0_1
  329. [AVR32] avr32
  330. [X86-32] pit,hpet,tsc,vmi-timer;
  331. scx200_hrt on Geode; cyclone on IBM x440
  332. [MIPS] MIPS
  333. [PARISC] cr16
  334. [S390] tod
  335. [SH] SuperH
  336. [SPARC64] tick
  337. [X86-64] hpet,tsc
  338. code_bytes [IA32] How many bytes of object code to print in an
  339. oops report.
  340. Range: 0 - 8192
  341. Default: 64
  342. disable_8254_timer
  343. enable_8254_timer
  344. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  345. over the 8254 in addition to over the IO-APIC. The
  346. kernel tries to set a sensible default.
  347. hpet= [X86-32,HPET] option to disable HPET and use PIT.
  348. Format: disable
  349. com20020= [HW,NET] ARCnet - COM20020 chipset
  350. Format:
  351. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  352. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  353. Format: <io>[,<irq>]
  354. com90xx= [HW,NET]
  355. ARCnet - COM90xx chipset (memory-mapped buffers)
  356. Format: <io>[,<irq>[,<memstart>]]
  357. condev= [HW,S390] console device
  358. conmode=
  359. console= [KNL] Output console device and options.
  360. tty<n> Use the virtual console device <n>.
  361. ttyS<n>[,options]
  362. ttyUSB0[,options]
  363. Use the specified serial port. The options are of
  364. the form "bbbbpnf", where "bbbb" is the baud rate,
  365. "p" is parity ("n", "o", or "e"), "n" is number of
  366. bits, and "f" is flow control ("r" for RTS or
  367. omit it). Default is "9600n8".
  368. See Documentation/serial-console.txt for more
  369. information. See
  370. Documentation/networking/netconsole.txt for an
  371. alternative.
  372. uart[8250],io,<addr>[,options]
  373. uart[8250],mmio,<addr>[,options]
  374. Start an early, polled-mode console on the 8250/16550
  375. UART at the specified I/O port or MMIO address,
  376. switching to the matching ttyS device later. The
  377. options are the same as for ttyS, above.
  378. earlycon= [KNL] Output early console device and options.
  379. uart[8250],io,<addr>[,options]
  380. uart[8250],mmio,<addr>[,options]
  381. Start an early, polled-mode console on the 8250/16550
  382. UART at the specified I/O port or MMIO address.
  383. The options are the same as for ttyS, above.
  384. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  385. Format:
  386. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  387. crashkernel=nn[KMG]@ss[KMG]
  388. [KNL] Reserve a chunk of physical memory to
  389. hold a kernel to switch to with kexec on panic.
  390. cs4232= [HW,OSS]
  391. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  392. cs89x0_dma= [HW,NET]
  393. Format: <dma>
  394. cs89x0_media= [HW,NET]
  395. Format: { rj45 | aui | bnc }
  396. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  397. dasd= [HW,NET]
  398. See header of drivers/s390/block/dasd_devmap.c.
  399. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  400. (one device per port)
  401. Format: <port#>,<type>
  402. See also Documentation/input/joystick-parport.txt
  403. debug [KNL] Enable kernel debugging (events log level).
  404. debug_locks_verbose=
  405. [KNL] verbose self-tests
  406. Format=<0|1>
  407. Print debugging info while doing the locking API
  408. self-tests.
  409. We default to 0 (no extra messages), setting it to
  410. 1 will print _a lot_ more information - normally
  411. only useful to kernel developers.
  412. decnet= [HW,NET]
  413. Format: <area>[,<node>]
  414. See also Documentation/networking/decnet.txt.
  415. default_blu= [VT]
  416. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  417. Change the default blue palette of the console.
  418. This is a 16-member array composed of values
  419. ranging from 0-255.
  420. default_grn= [VT]
  421. Format: <green0>,<green1>,<green2>,...,<green15>
  422. Change the default green palette of the console.
  423. This is a 16-member array composed of values
  424. ranging from 0-255.
  425. default_red= [VT]
  426. Format: <red0>,<red1>,<red2>,...,<red15>
  427. Change the default red palette of the console.
  428. This is a 16-member array composed of values
  429. ranging from 0-255.
  430. default_utf8= [VT]
  431. Format=<0|1>
  432. Set system-wide default UTF-8 mode for all tty's.
  433. Default is 0 and by setting to 1, it enables UTF-8
  434. mode for all newly opened or allocated terminals.
  435. dhash_entries= [KNL]
  436. Set number of hash buckets for dentry cache.
  437. digi= [HW,SERIAL]
  438. IO parameters + enable/disable command.
  439. digiepca= [HW,SERIAL]
  440. See drivers/char/README.epca and
  441. Documentation/digiepca.txt.
  442. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  443. support available.
  444. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  445. dmasound= [HW,OSS] Sound subsystem buffers
  446. dscc4.setup= [NET]
  447. dtc3181e= [HW,SCSI]
  448. earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
  449. earlyprintk=vga
  450. earlyprintk=serial[,ttySn[,baudrate]]
  451. Append ",keep" to not disable it when the real console
  452. takes over.
  453. Only vga or serial at a time, not both.
  454. Currently only ttyS0 and ttyS1 are supported.
  455. Interaction with the standard serial driver is not
  456. very good.
  457. The VGA output is eventually overwritten by the real
  458. console.
  459. eata= [HW,SCSI]
  460. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  461. Format: <int>
  462. 0: polling mode
  463. non-0: interrupt mode (default)
  464. eda= [HW,PS2]
  465. edb= [HW,PS2]
  466. edd= [EDD]
  467. Format: {"of[f]" | "sk[ipmbr]"}
  468. See comment in arch/i386/boot/edd.S
  469. eicon= [HW,ISDN]
  470. Format: <id>,<membase>,<irq>
  471. eisa_irq_edge= [PARISC,HW]
  472. See header of drivers/parisc/eisa.c.
  473. elanfreq= [X86-32]
  474. See comment before function elanfreq_setup() in
  475. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  476. elevator= [IOSCHED]
  477. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  478. See Documentation/block/as-iosched.txt and
  479. Documentation/block/deadline-iosched.txt for details.
  480. elfcorehdr= [X86-32, X86_64]
  481. Specifies physical address of start of kernel core
  482. image elf header. Generally kexec loader will
  483. pass this option to capture kernel.
  484. See Documentation/kdump/kdump.txt for details.
  485. enforcing [SELINUX] Set initial enforcing status.
  486. Format: {"0" | "1"}
  487. See security/selinux/Kconfig help text.
  488. 0 -- permissive (log only, no denials).
  489. 1 -- enforcing (deny and log).
  490. Default value is 0.
  491. Value can be changed at runtime via /selinux/enforce.
  492. es1371= [HW,OSS]
  493. Format: <spdif>,[<nomix>,[<amplifier>]]
  494. See also header of sound/oss/es1371.c.
  495. ether= [HW,NET] Ethernet cards parameters
  496. This option is obsoleted by the "netdev=" option, which
  497. has equivalent usage. See its documentation for details.
  498. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  499. Format: <io>[,<irq>]
  500. failslab=
  501. fail_page_alloc=
  502. fail_make_request=[KNL]
  503. General fault injection mechanism.
  504. Format: <interval>,<probability>,<space>,<times>
  505. See also /Documentation/fault-injection/.
  506. fd_mcs= [HW,SCSI]
  507. See header of drivers/scsi/fd_mcs.c.
  508. fdomain= [HW,SCSI]
  509. See header of drivers/scsi/fdomain.c.
  510. floppy= [HW]
  511. See Documentation/floppy.txt.
  512. gamecon.map[2|3]=
  513. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  514. support via parallel port (up to 5 devices per port)
  515. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  516. See also Documentation/input/joystick-parport.txt
  517. gamma= [HW,DRM]
  518. gdth= [HW,SCSI]
  519. See header of drivers/scsi/gdth.c.
  520. gpt [EFI] Forces disk with valid GPT signature but
  521. invalid Protective MBR to be treated as GPT.
  522. gvp11= [HW,SCSI]
  523. hashdist= [KNL,NUMA] Large hashes allocated during boot
  524. are distributed across NUMA nodes. Defaults on
  525. for IA-64, off otherwise.
  526. Format: 0 | 1 (for off | on)
  527. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  528. hd= [EIDE] (E)IDE hard drive subsystem geometry
  529. Format: <cyl>,<head>,<sect>
  530. hd?= [HW] (E)IDE subsystem
  531. hd?lun= See Documentation/ide.txt.
  532. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  533. size of <nn>. This works even on boxes that have no
  534. highmem otherwise. This also works to reduce highmem
  535. size on bigger boxes.
  536. highres= [KNL] Enable/disable high resolution timer mode.
  537. Valid parameters: "on", "off"
  538. Default: "on"
  539. hisax= [HW,ISDN]
  540. See Documentation/isdn/README.HiSax.
  541. hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
  542. i8042.direct [HW] Put keyboard port into non-translated mode
  543. i8042.dumbkbd [HW] Pretend that controller can only read data from
  544. keyboard and cannot control its state
  545. (Don't attempt to blink the leds)
  546. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  547. i8042.nokbd [HW] Don't check/create keyboard port
  548. i8042.nomux [HW] Don't check presence of an active multiplexing
  549. controller
  550. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  551. controllers
  552. i8042.panicblink=
  553. [HW] Frequency with which keyboard LEDs should blink
  554. when kernel panics (default is 0.5 sec)
  555. i8042.reset [HW] Reset the controller during init and cleanup
  556. i8042.unlock [HW] Unlock (ignore) the keylock
  557. i810= [HW,DRM]
  558. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  559. indicates that the driver is running on unsupported
  560. hardware.
  561. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  562. does not match list of supported models.
  563. i8k.power_status
  564. [HW] Report power status in /proc/i8k
  565. (disabled by default)
  566. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  567. capability is set.
  568. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  569. See Documentation/mca.txt.
  570. icn= [HW,ISDN]
  571. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  572. ide= [HW] (E)IDE subsystem
  573. Format: ide=nodma or ide=doubler or ide=reverse
  574. See Documentation/ide.txt.
  575. ide?= [HW] (E)IDE subsystem
  576. Format: ide?=noprobe or chipset specific parameters.
  577. See Documentation/ide.txt.
  578. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  579. See Documentation/ide.txt.
  580. idle= [X86]
  581. Format: idle=poll or idle=mwait
  582. Poll forces a polling idle loop that can slightly improves the performance
  583. of waking up a idle CPU, but will use a lot of power and make the system
  584. run hot. Not recommended.
  585. idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
  586. to not use it because it doesn't save as much power as a normal idle
  587. loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
  588. as idle=poll.
  589. ignore_loglevel [KNL]
  590. Ignore loglevel setting - this will print /all/
  591. kernel messages to the console. Useful for debugging.
  592. ihash_entries= [KNL]
  593. Set number of hash buckets for inode cache.
  594. in2000= [HW,SCSI]
  595. See header of drivers/scsi/in2000.c.
  596. init= [KNL]
  597. Format: <full_path>
  598. Run specified binary instead of /sbin/init as init
  599. process.
  600. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  601. for working out where the kernel is dying during
  602. startup.
  603. initrd= [BOOT] Specify the location of the initial ramdisk
  604. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  605. Format: <irq>
  606. inttest= [IA64]
  607. io7= [HW] IO7 for Marvel based alpha systems
  608. See comment before marvel_specify_io7 in
  609. arch/alpha/kernel/core_marvel.c.
  610. ip= [IP_PNP]
  611. See Documentation/nfsroot.txt.
  612. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  613. See comment before ip2_setup() in
  614. drivers/char/ip2/ip2base.c.
  615. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  616. See header of drivers/scsi/ips.c.
  617. ports= [IP_VS_FTP] IPVS ftp helper module
  618. Default is 21.
  619. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  620. may be specified.
  621. Format: <port>,<port>....
  622. irqfixup [HW]
  623. When an interrupt is not handled search all handlers
  624. for it. Intended to get systems with badly broken
  625. firmware running.
  626. irqpoll [HW]
  627. When an interrupt is not handled search all handlers
  628. for it. Also check all handlers each timer
  629. interrupt. Intended to get systems with badly broken
  630. firmware running.
  631. isapnp= [ISAPNP]
  632. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  633. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  634. Format:
  635. <cpu number>,...,<cpu number>
  636. or
  637. <cpu number>-<cpu number> (must be a positive range in ascending order)
  638. or a mixture
  639. <cpu number>,...,<cpu number>-<cpu number>
  640. This option can be used to specify one or more CPUs
  641. to isolate from the general SMP balancing and scheduling
  642. algorithms. The only way to move a process onto or off
  643. an "isolated" CPU is via the CPU affinity syscalls.
  644. <cpu number> begins at 0 and the maximum value is
  645. "number of CPUs in system - 1".
  646. This option is the preferred way to isolate CPUs. The
  647. alternative -- manually setting the CPU mask of all
  648. tasks in the system -- can cause problems and
  649. suboptimal load balancer performance.
  650. iucv= [HW,NET]
  651. js= [HW,JOY] Analog joystick
  652. See Documentation/input/joystick.txt.
  653. kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  654. specifies the amount of memory usable by the kernel
  655. for non-movable allocations. The requested amount is
  656. spread evenly throughout all nodes in the system. The
  657. remaining memory in each node is used for Movable
  658. pages. In the event, a node is too small to have both
  659. kernelcore and Movable pages, kernelcore pages will
  660. take priority and other nodes will have a larger number
  661. of kernelcore pages. The Movable zone is used for the
  662. allocation of pages that may be reclaimed or moved
  663. by the page migration subsystem. This means that
  664. HugeTLB pages may not be allocated from this zone.
  665. Note that allocations like PTEs-from-HighMem still
  666. use the HighMem zone if it exists, and the Normal
  667. zone if it does not.
  668. movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  669. is similar to kernelcore except it specifies the
  670. amount of memory used for migratable allocations.
  671. If both kernelcore and movablecore is specified,
  672. then kernelcore will be at *least* the specified
  673. value but may be more. If movablecore on its own
  674. is specified, the administrator must be careful
  675. that the amount of memory usable for all allocations
  676. is not too small.
  677. keepinitrd [HW,ARM]
  678. kstack=N [X86-32,X86-64] Print N words from the kernel stack
  679. in oops dumps.
  680. l2cr= [PPC]
  681. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  682. disabled it.
  683. lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
  684. C2 power state.
  685. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  686. Format: addr:<io>,irq:<irq>
  687. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  688. when set.
  689. Format: <int>
  690. load_ramdisk= [RAM] List of ramdisks to load from floppy
  691. See Documentation/ramdisk.txt.
  692. lockd.nlm_grace_period=P [NFS] Assign grace period.
  693. Format: <integer>
  694. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  695. Format: <integer>
  696. lockd.nlm_timeout=T [NFS] Assign timeout value.
  697. Format: <integer>
  698. lockd.nlm_udpport=M [NFS] Assign UDP port.
  699. Format: <integer>
  700. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  701. Format: <irq>
  702. loglevel= All Kernel Messages with a loglevel smaller than the
  703. console loglevel will be printed to the console. It can
  704. also be changed with klogd or other programs. The
  705. loglevels are defined as follows:
  706. 0 (KERN_EMERG) system is unusable
  707. 1 (KERN_ALERT) action must be taken immediately
  708. 2 (KERN_CRIT) critical conditions
  709. 3 (KERN_ERR) error conditions
  710. 4 (KERN_WARNING) warning conditions
  711. 5 (KERN_NOTICE) normal but significant condition
  712. 6 (KERN_INFO) informational
  713. 7 (KERN_DEBUG) debug-level messages
  714. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  715. Format: { n | nk | nM }
  716. n must be a power of two. The default size
  717. is set in the kernel config file.
  718. logo.nologo [FB] Disables display of the built-in Linux logo.
  719. This may be used to provide more screen space for
  720. kernel log messages and is useful when debugging
  721. kernel boot problems.
  722. lp=0 [LP] Specify parallel ports to use, e.g,
  723. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  724. lp=reset first parallel port). 'lp=0' disables the
  725. lp=auto printer driver. 'lp=reset' (which can be
  726. specified in addition to the ports) causes
  727. attached printers to be reset. Using
  728. lp=port1,port2,... specifies the parallel ports
  729. to associate lp devices with, starting with
  730. lp0. A port specification may be 'none' to skip
  731. that lp device, or a parport name such as
  732. 'parport0'. Specifying 'lp=auto' instead of a
  733. port specification list means that device IDs
  734. from each port should be examined, to see if
  735. an IEEE 1284-compliant printer is attached; if
  736. so, the driver will manage that printer.
  737. See also header of drivers/char/lp.c.
  738. lpj=n [KNL]
  739. Sets loops_per_jiffy to given constant, thus avoiding
  740. time-consuming boot-time autodetection (up to 250 ms per
  741. CPU). 0 enables autodetection (default). To determine
  742. the correct value for your kernel, boot with normal
  743. autodetection and see what value is printed. Note that
  744. on SMP systems the preset will be applied to all CPUs,
  745. which is likely to cause problems if your CPUs need
  746. significantly divergent settings. An incorrect value
  747. will cause delays in the kernel to be wrong, leading to
  748. unpredictable I/O errors and other breakage. Although
  749. unlikely, in the extreme case this might damage your
  750. hardware.
  751. ltpc= [NET]
  752. Format: <io>,<irq>,<dma>
  753. mac5380= [HW,SCSI] Format:
  754. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  755. mac53c9x= [HW,SCSI] Format:
  756. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  757. machvec= [IA64] Force the use of a particular machine-vector
  758. (machvec) in a generic kernel.
  759. Example: machvec=hpzx1_swiotlb
  760. max_loop= [LOOP] Maximum number of loopback devices that can
  761. be mounted
  762. Format: <1-256>
  763. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  764. should make use of. maxcpus=n : n >= 0 limits the
  765. kernel to using 'n' processors. n=0 is a special case,
  766. it is equivalent to "nosmp", which also disables
  767. the IO APIC.
  768. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  769. equal to this physical address is ignored.
  770. max_luns= [SCSI] Maximum number of LUNs to probe.
  771. Should be between 1 and 2^32-1.
  772. max_report_luns=
  773. [SCSI] Maximum number of LUNs received.
  774. Should be between 1 and 16384.
  775. mca-pentium [BUGS=X86-32]
  776. mcatest= [IA-64]
  777. mce [X86-32] Machine Check Exception
  778. md= [HW] RAID subsystems devices and level
  779. See Documentation/md.txt.
  780. mdacon= [MDA]
  781. Format: <first>,<last>
  782. Specifies range of consoles to be captured by the MDA.
  783. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  784. Amount of memory to be used when the kernel is not able
  785. to see the whole system memory or for test.
  786. [X86-32] Use together with memmap= to avoid physical
  787. address space collisions. Without memmap= PCI devices
  788. could be placed at addresses belonging to unused RAM.
  789. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  790. memory.
  791. memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
  792. E820 memory map, as specified by the user.
  793. Such memmap=exactmap lines can be constructed based on
  794. BIOS output or other requirements. See the memmap=nn@ss
  795. option description.
  796. memmap=nn[KMG]@ss[KMG]
  797. [KNL] Force usage of a specific region of memory
  798. Region of memory to be used, from ss to ss+nn.
  799. memmap=nn[KMG]#ss[KMG]
  800. [KNL,ACPI] Mark specific memory as ACPI data.
  801. Region of memory to be used, from ss to ss+nn.
  802. memmap=nn[KMG]$ss[KMG]
  803. [KNL,ACPI] Mark specific memory as reserved.
  804. Region of memory to be used, from ss to ss+nn.
  805. meye.*= [HW] Set MotionEye Camera parameters
  806. See Documentation/video4linux/meye.txt.
  807. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  808. Multi-Function General Purpose Timers on AMD Geode
  809. platforms.
  810. mga= [HW,DRM]
  811. mousedev.tap_time=
  812. [MOUSE] Maximum time between finger touching and
  813. leaving touchpad surface for touch to be considered
  814. a tap and be reported as a left button click (for
  815. touchpads working in absolute mode only).
  816. Format: <msecs>
  817. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  818. reporting absolute coordinates, such as tablets
  819. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  820. reporting absolute coordinates, such as tablets
  821. mpu401= [HW,OSS]
  822. Format: <io>,<irq>
  823. MTD_Partition= [MTD]
  824. Format: <name>,<region-number>,<size>,<offset>
  825. MTD_Region= [MTD] Format:
  826. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  827. mtdparts= [MTD]
  828. See drivers/mtd/cmdlinepart.c.
  829. mtouchusb.raw_coordinates=
  830. [HW] Make the MicroTouch USB driver use raw coordinates
  831. ('y', default) or cooked coordinates ('n')
  832. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  833. NCR_D700= [HW,SCSI]
  834. See header of drivers/scsi/NCR_D700.c.
  835. ncr5380= [HW,SCSI]
  836. ncr53c400= [HW,SCSI]
  837. ncr53c400a= [HW,SCSI]
  838. ncr53c406a= [HW,SCSI]
  839. ncr53c8xx= [HW,SCSI]
  840. netdev= [NET] Network devices parameters
  841. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  842. Note that mem_start is often overloaded to mean
  843. something different and driver-specific.
  844. This usage is only documented in each driver source
  845. file if at all.
  846. nfsaddrs= [NFS]
  847. See Documentation/nfsroot.txt.
  848. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  849. See Documentation/nfsroot.txt.
  850. nfs.callback_tcpport=
  851. [NFS] set the TCP port on which the NFSv4 callback
  852. channel should listen.
  853. nfs.idmap_cache_timeout=
  854. [NFS] set the maximum lifetime for idmapper cache
  855. entries.
  856. nfs.enable_ino64=
  857. [NFS] enable 64-bit inode numbers.
  858. If zero, the NFS client will fake up a 32-bit inode
  859. number for the readdir() and stat() syscalls instead
  860. of returning the full 64-bit number.
  861. The default is to return 64-bit inode numbers.
  862. nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
  863. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  864. emulation library even if a 387 maths coprocessor
  865. is present.
  866. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  867. caches in the slab allocator. Saves per-node memory,
  868. but will impact performance.
  869. noalign [KNL,ARM]
  870. noapic [SMP,APIC] Tells the kernel to not make use of any
  871. IOAPICs that may be present in the system.
  872. noasync [HW,M68K] Disables async and sync negotiation for
  873. all devices.
  874. nobats [PPC] Do not use BATs for mapping kernel lowmem
  875. on "Classic" PPC cores.
  876. nocache [ARM]
  877. nodelayacct [KNL] Disable per-task delay accounting
  878. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  879. noexec [IA-64]
  880. noexec [X86-32,X86-64]
  881. noexec=on: enable non-executable mappings (default)
  882. noexec=off: disable nn-executable mappings
  883. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  884. register save and restore. The kernel will only save
  885. legacy floating-point registers on task switch.
  886. nohlt [BUGS=ARM]
  887. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  888. instruction doesn't work correctly and not to
  889. use it.
  890. nohalt [IA-64] Tells the kernel not to use the power saving
  891. function PAL_HALT_LIGHT when idle. This increases
  892. power-consumption. On the positive side, it reduces
  893. interrupt wake-up latency, which may improve performance
  894. in certain environments such as networked servers or
  895. real-time systems.
  896. nohz= [KNL] Boottime enable/disable dynamic ticks
  897. Valid arguments: on, off
  898. Default: on
  899. noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
  900. noirqdebug [X86-32] Disables the code which attempts to detect and
  901. disable unhandled interrupt sources.
  902. no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
  903. broken timer IRQ sources.
  904. noisapnp [ISAPNP] Disables ISA PnP code.
  905. noinitrd [RAM] Tells the kernel not to load any configured
  906. initial RAM disk.
  907. nointroute [IA-64]
  908. nojitter [IA64] Disables jitter checking for ITC timers.
  909. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  910. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  911. noltlbs [PPC] Do not use large page/tlb entries for kernel
  912. lowmem mapping on PPC40x.
  913. nomca [IA-64] Disable machine check abort handling
  914. nomce [X86-32] Machine Check Exception
  915. nomfgpt [X86-32] Disable Multi-Function General Purpose
  916. Timer usage (for AMD Geode machines).
  917. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  918. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  919. with UP alternatives
  920. noresidual [PPC] Don't use residual data on PReP machines.
  921. noresume [SWSUSP] Disables resume and restores original swap
  922. space.
  923. no-scroll [VGA] Disables scrollback.
  924. This is required for the Braillex ib80-piezo Braille
  925. reader made by F.H. Papenmeier (Germany).
  926. nosbagart [IA-64]
  927. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  928. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  929. and disable the IO APIC. legacy for "maxcpus=0".
  930. nosoftlockup [KNL] Disable the soft-lockup detector.
  931. nosync [HW,M68K] Disables sync negotiation for all devices.
  932. notsc [BUGS=X86-32] Disable Time Stamp Counter
  933. nousb [USB] Disable the USB subsystem
  934. nowb [ARM]
  935. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  936. one of ['zone', 'node', 'default'] can be specified
  937. This can be set from sysctl after boot.
  938. See Documentation/sysctl/vm.txt for details.
  939. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  940. opl3= [HW,OSS]
  941. Format: <io>
  942. oprofile.timer= [HW]
  943. Use timer interrupt instead of performance counters
  944. osst= [HW,SCSI] SCSI Tape Driver
  945. Format: <buffer_size>,<write_threshold>
  946. See also Documentation/scsi/st.txt.
  947. panic= [KNL] Kernel behaviour on panic
  948. Format: <timeout>
  949. parkbd.port= [HW] Parallel port number the keyboard adapter is
  950. connected to, default is 0.
  951. Format: <parport#>
  952. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  953. 0 for XT, 1 for AT (default is AT).
  954. Format: <mode>
  955. parport= [HW,PPT] Specify parallel ports. 0 disables.
  956. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  957. Use 'auto' to force the driver to use any
  958. IRQ/DMA settings detected (the default is to
  959. ignore detected IRQ/DMA settings because of
  960. possible conflicts). You can specify the base
  961. address, IRQ, and DMA settings; IRQ and DMA
  962. should be numbers, or 'auto' (for using detected
  963. settings on that particular port), or 'nofifo'
  964. (to avoid using a FIFO even if it is detected).
  965. Parallel ports are assigned in the order they
  966. are specified on the command line, starting
  967. with parport0.
  968. parport_init_mode= [HW,PPT]
  969. Configure VIA parallel port to operate in
  970. a specific mode. This is necessary on Pegasos
  971. computer where firmware has no options for setting
  972. up parallel port mode and sets it to spp.
  973. Currently this function knows 686a and 8231 chips.
  974. Format: [spp|ps2|epp|ecp|ecpepp]
  975. pas2= [HW,OSS] Format:
  976. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  977. pas16= [HW,SCSI]
  978. See header of drivers/scsi/pas16.c.
  979. pause_on_oops=
  980. Halt all CPUs after the first oops has been printed for
  981. the specified number of seconds. This is to be used if
  982. your oopses keep scrolling off the screen.
  983. pcbit= [HW,ISDN]
  984. pcd. [PARIDE]
  985. See header of drivers/block/paride/pcd.c.
  986. See also Documentation/paride.txt.
  987. pci=option[,option...] [PCI] various PCI subsystem options:
  988. off [X86-32] don't probe for the PCI bus
  989. bios [X86-32] force use of PCI BIOS, don't access
  990. the hardware directly. Use this if your machine
  991. has a non-standard PCI host bridge.
  992. nobios [X86-32] disallow use of PCI BIOS, only direct
  993. hardware access methods are allowed. Use this
  994. if you experience crashes upon bootup and you
  995. suspect they are caused by the BIOS.
  996. conf1 [X86-32] Force use of PCI Configuration
  997. Mechanism 1.
  998. conf2 [X86-32] Force use of PCI Configuration
  999. Mechanism 2.
  1000. noaer [PCIE] If the PCIEAER kernel config parameter is
  1001. enabled, this kernel boot option can be used to
  1002. disable the use of PCIE advanced error reporting.
  1003. nodomains [PCI] Disable support for multiple PCI
  1004. root domains (aka PCI segments, in ACPI-speak).
  1005. nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
  1006. Configuration
  1007. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1008. enabled, this kernel boot option can be used to
  1009. disable the use of MSI interrupts system-wide.
  1010. nosort [X86-32] Don't sort PCI devices according to
  1011. order given by the PCI BIOS. This sorting is
  1012. done to get a device order compatible with
  1013. older kernels.
  1014. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1015. routing table. These calls are known to be buggy
  1016. on several machines and they hang the machine
  1017. when used, but on other computers it's the only
  1018. way to get the interrupt routing table. Try
  1019. this option if the kernel is unable to allocate
  1020. IRQs or discover secondary PCI buses on your
  1021. motherboard.
  1022. rom [X86-32] Assign address space to expansion ROMs.
  1023. Use with caution as certain devices share
  1024. address decoders between ROMs and other
  1025. resources.
  1026. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
  1027. assigned automatically to PCI devices. You can
  1028. make the kernel exclude IRQs of your ISA cards
  1029. this way.
  1030. pirqaddr=0xAAAAA [X86-32] Specify the physical address
  1031. of the PIRQ table (normally generated
  1032. by the BIOS) if it is outside the
  1033. F0000h-100000h range.
  1034. lastbus=N [X86-32] Scan all buses thru bus #N. Can be
  1035. useful if the kernel is unable to find your
  1036. secondary buses and you want to tell it
  1037. explicitly which ones they are.
  1038. assign-busses [X86-32] Always assign all PCI bus
  1039. numbers ourselves, overriding
  1040. whatever the firmware may have done.
  1041. usepirqmask [X86-32] Honor the possible IRQ mask stored
  1042. in the BIOS $PIR table. This is needed on
  1043. some systems with broken BIOSes, notably
  1044. some HP Pavilion N5400 and Omnibook XE3
  1045. notebooks. This will have no effect if ACPI
  1046. IRQ routing is enabled.
  1047. noacpi [X86-32] Do not use ACPI for IRQ routing
  1048. or for PCI scanning.
  1049. use_crs [X86-32] Use _CRS for PCI resource
  1050. allocation.
  1051. routeirq Do IRQ routing for all PCI devices.
  1052. This is normally done in pci_enable_device(),
  1053. so this option is a temporary workaround
  1054. for broken drivers that don't call it.
  1055. firmware [ARM] Do not re-enumerate the bus but instead
  1056. just use the configuration from the
  1057. bootloader. This is currently used on
  1058. IXP2000 systems where the bus has to be
  1059. configured a certain way for adjunct CPUs.
  1060. noearly [X86] Don't do any early type 1 scanning.
  1061. This might help on some broken boards which
  1062. machine check when some devices' config space
  1063. is read. But various workarounds are disabled
  1064. and some IOMMU drivers will not work.
  1065. bfsort Sort PCI devices into breadth-first order.
  1066. This sorting is done to get a device
  1067. order compatible with older (<= 2.4) kernels.
  1068. nobfsort Don't sort PCI devices into breadth-first order.
  1069. cbiosize=nn[KMG] The fixed amount of bus space which is
  1070. reserved for the CardBus bridge's IO window.
  1071. The default value is 256 bytes.
  1072. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1073. reserved for the CardBus bridge's memory
  1074. window. The default value is 64 megabytes.
  1075. pcmv= [HW,PCMCIA] BadgePAD 4
  1076. pd. [PARIDE]
  1077. See Documentation/paride.txt.
  1078. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1079. boot time.
  1080. Format: { 0 | 1 }
  1081. See arch/parisc/kernel/pdc_chassis.c
  1082. pf. [PARIDE]
  1083. See Documentation/paride.txt.
  1084. pg. [PARIDE]
  1085. See Documentation/paride.txt.
  1086. pirq= [SMP,APIC] Manual mp-table setup
  1087. See Documentation/i386/IO-APIC.txt.
  1088. plip= [PPT,NET] Parallel port network link
  1089. Format: { parport<nr> | timid | 0 }
  1090. See also Documentation/parport.txt.
  1091. pnpacpi= [ACPI]
  1092. { off }
  1093. pnpbios= [ISAPNP]
  1094. { on | off | curr | res | no-curr | no-res }
  1095. pnp_reserve_irq=
  1096. [ISAPNP] Exclude IRQs for the autoconfiguration
  1097. pnp_reserve_dma=
  1098. [ISAPNP] Exclude DMAs for the autoconfiguration
  1099. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1100. Ranges are in pairs (I/O port base and size).
  1101. pnp_reserve_mem=
  1102. [ISAPNP] Exclude memory regions for the
  1103. autoconfiguration.
  1104. Ranges are in pairs (memory base and size).
  1105. print-fatal-signals=
  1106. [KNL] debug: print fatal signals
  1107. print-fatal-signals=1: print segfault info to
  1108. the kernel console.
  1109. default: off.
  1110. printk.time= Show timing data prefixed to each printk message line
  1111. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1112. profile= [KNL] Enable kernel profiling via /proc/profile
  1113. Format: [schedule,]<number>
  1114. Param: "schedule" - profile schedule points.
  1115. Param: <number> - step/bucket size as a power of 2 for
  1116. statistical time based profiling.
  1117. Param: "sleep" - profile D-state sleeping (millisecs)
  1118. processor.max_cstate= [HW,ACPI]
  1119. Limit processor to maximum C-state
  1120. max_cstate=9 overrides any DMI blacklist limit.
  1121. processor.nocst [HW,ACPI]
  1122. Ignore the _CST method to determine C-states,
  1123. instead using the legacy FADT method
  1124. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1125. before loading.
  1126. See Documentation/ramdisk.txt.
  1127. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1128. probe for; one of (bare|imps|exps|lifebook|any).
  1129. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1130. per second.
  1131. psmouse.resetafter= [HW,MOUSE]
  1132. Try to reset the device after so many bad packets
  1133. (0 = never).
  1134. psmouse.resolution=
  1135. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1136. psmouse.smartscroll=
  1137. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1138. 0 = disabled, 1 = enabled (default).
  1139. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1140. Format:
  1141. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1142. pt. [PARIDE]
  1143. See Documentation/paride.txt.
  1144. pty.legacy_count=
  1145. [KNL] Number of legacy pty's. Overwrites compiled-in
  1146. default number.
  1147. quiet [KNL] Disable most log messages
  1148. r128= [HW,DRM]
  1149. raid= [HW,RAID]
  1150. See Documentation/md.txt.
  1151. ramdisk_blocksize= [RAM]
  1152. See Documentation/ramdisk.txt.
  1153. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1154. See Documentation/ramdisk.txt.
  1155. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1156. RCU callbacks to process in one batch.
  1157. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1158. RCU callbacks over which batch limiting is disabled.
  1159. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1160. RCU callbacks below which batch limiting is re-enabled.
  1161. rdinit= [KNL]
  1162. Format: <full_path>
  1163. Run specified binary instead of /init from the ramdisk,
  1164. used for early userspace startup. See initrd.
  1165. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1166. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1167. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1168. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1169. reservetop= [X86-32]
  1170. Format: nn[KMG]
  1171. Reserves a hole at the top of the kernel virtual
  1172. address space.
  1173. reset_devices [KNL] Force drivers to reset the underlying device
  1174. during initialization.
  1175. resume= [SWSUSP]
  1176. Specify the partition device for software suspend
  1177. resume_offset= [SWSUSP]
  1178. Specify the offset from the beginning of the partition
  1179. given by "resume=" at which the swap header is located,
  1180. in <PAGE_SIZE> units (needed only for swap files).
  1181. See Documentation/power/swsusp-and-swap-files.txt
  1182. retain_initrd [RAM] Keep initrd memory after extraction
  1183. rhash_entries= [KNL,NET]
  1184. Set number of hash buckets for route cache
  1185. riscom8= [HW,SERIAL]
  1186. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1187. ro [KNL] Mount root device read-only on boot
  1188. root= [KNL] Root filesystem
  1189. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1190. mount the root filesystem
  1191. rootflags= [KNL] Set root filesystem mount option string
  1192. rootfstype= [KNL] Set root filesystem type
  1193. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1194. Useful for devices that are detected asynchronously
  1195. (e.g. USB and MMC devices).
  1196. rw [KNL] Mount root device read-write on boot
  1197. S [KNL] Run init in single mode
  1198. sa1100ir [NET]
  1199. See drivers/net/irda/sa1100_ir.c.
  1200. sb= [HW,OSS]
  1201. Format: <io>,<irq>,<dma>,<dma2>
  1202. sbni= [NET] Granch SBNI12 leased line adapter
  1203. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1204. Format: <io>[,<timeout>[,<isapnp>]]
  1205. scsi_debug_*= [SCSI]
  1206. See drivers/scsi/scsi_debug.c.
  1207. scsi_default_dev_flags=
  1208. [SCSI] SCSI default device flags
  1209. Format: <integer>
  1210. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1211. Format: <vendor>:<model>:<flags>
  1212. (flags are integer value)
  1213. scsi_logging= [SCSI]
  1214. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1215. discovered. async scans them in kernel threads,
  1216. allowing boot to proceed. none ignores them, expecting
  1217. user space to do the scan.
  1218. selinux [SELINUX] Disable or enable SELinux at boot time.
  1219. Format: { "0" | "1" }
  1220. See security/selinux/Kconfig help text.
  1221. 0 -- disable.
  1222. 1 -- enable.
  1223. Default value is set via kernel config option.
  1224. If enabled at boot time, /selinux/disable can be used
  1225. later to disable prior to initial policy load.
  1226. selinux_compat_net =
  1227. [SELINUX] Set initial selinux_compat_net flag value.
  1228. Format: { "0" | "1" }
  1229. 0 -- use new secmark-based packet controls
  1230. 1 -- use legacy packet controls
  1231. Default value is 0 (preferred).
  1232. Value can be changed at runtime via
  1233. /selinux/compat_net.
  1234. serialnumber [BUGS=X86-32]
  1235. sg_def_reserved_size= [SCSI]
  1236. shapers= [NET]
  1237. Maximal number of shapers.
  1238. sim710= [SCSI,HW]
  1239. See header of drivers/scsi/sim710.c.
  1240. simeth= [IA-64]
  1241. simscsi=
  1242. slram= [HW,MTD]
  1243. slub_debug[=options[,slabs]] [MM, SLUB]
  1244. Enabling slub_debug allows one to determine the
  1245. culprit if slab objects become corrupted. Enabling
  1246. slub_debug can create guard zones around objects and
  1247. may poison objects when not in use. Also tracks the
  1248. last alloc / free. For more information see
  1249. Documentation/vm/slub.txt.
  1250. slub_max_order= [MM, SLUB]
  1251. Determines the maximum allowed order for slabs.
  1252. A high setting may cause OOMs due to memory
  1253. fragmentation. For more information see
  1254. Documentation/vm/slub.txt.
  1255. slub_min_objects= [MM, SLUB]
  1256. The minimum number of objects per slab. SLUB will
  1257. increase the slab order up to slub_max_order to
  1258. generate a sufficiently large slab able to contain
  1259. the number of objects indicated. The higher the number
  1260. of objects the smaller the overhead of tracking slabs
  1261. and the less frequently locks need to be acquired.
  1262. For more information see Documentation/vm/slub.txt.
  1263. slub_min_order= [MM, SLUB]
  1264. Determines the mininum page order for slabs. Must be
  1265. lower than slub_max_order.
  1266. For more information see Documentation/vm/slub.txt.
  1267. slub_nomerge [MM, SLUB]
  1268. Disable merging of slabs with similar size. May be
  1269. necessary if there is some reason to distinguish
  1270. allocs to different slabs. Debug options disable
  1271. merging on their own.
  1272. For more information see Documentation/vm/slub.txt.
  1273. smart2= [HW]
  1274. Format: <io1>[,<io2>[,...,<io8>]]
  1275. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1276. attempt to substitute SMP alternatives once at boot.
  1277. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1278. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1279. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1280. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1281. smsc-ircc2.ircc_irq= [HW] IRQ line
  1282. smsc-ircc2.ircc_dma= [HW] DMA channel
  1283. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1284. 0: Toshiba Satellite 1800 (GP data pin select)
  1285. 1: Fast pin select (default)
  1286. 2: ATC IRMode
  1287. snd-ad1816a= [HW,ALSA]
  1288. snd-ad1848= [HW,ALSA]
  1289. snd-ali5451= [HW,ALSA]
  1290. snd-als100= [HW,ALSA]
  1291. snd-als4000= [HW,ALSA]
  1292. snd-azt2320= [HW,ALSA]
  1293. snd-cmi8330= [HW,ALSA]
  1294. snd-cmipci= [HW,ALSA]
  1295. snd-cs4231= [HW,ALSA]
  1296. snd-cs4232= [HW,ALSA]
  1297. snd-cs4236= [HW,ALSA]
  1298. snd-cs4281= [HW,ALSA]
  1299. snd-cs46xx= [HW,ALSA]
  1300. snd-dt019x= [HW,ALSA]
  1301. snd-dummy= [HW,ALSA]
  1302. snd-emu10k1= [HW,ALSA]
  1303. snd-ens1370= [HW,ALSA]
  1304. snd-ens1371= [HW,ALSA]
  1305. snd-es968= [HW,ALSA]
  1306. snd-es1688= [HW,ALSA]
  1307. snd-es18xx= [HW,ALSA]
  1308. snd-es1938= [HW,ALSA]
  1309. snd-es1968= [HW,ALSA]
  1310. snd-fm801= [HW,ALSA]
  1311. snd-gusclassic= [HW,ALSA]
  1312. snd-gusextreme= [HW,ALSA]
  1313. snd-gusmax= [HW,ALSA]
  1314. snd-hdsp= [HW,ALSA]
  1315. snd-ice1712= [HW,ALSA]
  1316. snd-intel8x0= [HW,ALSA]
  1317. snd-interwave= [HW,ALSA]
  1318. snd-interwave-stb=
  1319. [HW,ALSA]
  1320. snd-korg1212= [HW,ALSA]
  1321. snd-maestro3= [HW,ALSA]
  1322. snd-mpu401= [HW,ALSA]
  1323. snd-mtpav= [HW,ALSA]
  1324. snd-nm256= [HW,ALSA]
  1325. snd-opl3sa2= [HW,ALSA]
  1326. snd-opti92x-ad1848=
  1327. [HW,ALSA]
  1328. snd-opti92x-cs4231=
  1329. [HW,ALSA]
  1330. snd-opti93x= [HW,ALSA]
  1331. snd-pmac= [HW,ALSA]
  1332. snd-rme32= [HW,ALSA]
  1333. snd-rme96= [HW,ALSA]
  1334. snd-rme9652= [HW,ALSA]
  1335. snd-sb8= [HW,ALSA]
  1336. snd-sb16= [HW,ALSA]
  1337. snd-sbawe= [HW,ALSA]
  1338. snd-serial= [HW,ALSA]
  1339. snd-sgalaxy= [HW,ALSA]
  1340. snd-sonicvibes= [HW,ALSA]
  1341. snd-sun-amd7930=
  1342. [HW,ALSA]
  1343. snd-sun-cs4231= [HW,ALSA]
  1344. snd-trident= [HW,ALSA]
  1345. snd-usb-audio= [HW,ALSA,USB]
  1346. snd-via82xx= [HW,ALSA]
  1347. snd-virmidi= [HW,ALSA]
  1348. snd-wavefront= [HW,ALSA]
  1349. snd-ymfpci= [HW,ALSA]
  1350. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1351. See Documentation/sonypi.txt
  1352. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1353. See Documentation/specialix.txt.
  1354. spia_io_base= [HW,MTD]
  1355. spia_fio_base=
  1356. spia_pedr=
  1357. spia_peddr=
  1358. sscape= [HW,OSS]
  1359. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1360. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1361. See Documentation/scsi/st.txt.
  1362. st0x= [HW,SCSI]
  1363. See header of drivers/scsi/seagate.c.
  1364. sti= [PARISC,HW]
  1365. Format: <num>
  1366. Set the STI (builtin display/keyboard on the HP-PARISC
  1367. machines) console (graphic card) which should be used
  1368. as the initial boot-console.
  1369. See also comment in drivers/video/console/sticore.c.
  1370. sti_font= [HW]
  1371. See comment in drivers/video/console/sticore.c.
  1372. stifb= [HW]
  1373. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1374. sunrpc.pool_mode=
  1375. [NFS]
  1376. Control how the NFS server code allocates CPUs to
  1377. service thread pools. Depending on how many NICs
  1378. you have and where their interrupts are bound, this
  1379. option will affect which CPUs will do NFS serving.
  1380. Note: this parameter cannot be changed while the
  1381. NFS server is running.
  1382. auto the server chooses an appropriate mode
  1383. automatically using heuristics
  1384. global a single global pool contains all CPUs
  1385. percpu one pool for each CPU
  1386. pernode one pool for each NUMA node (equivalent
  1387. to global on non-NUMA machines)
  1388. swiotlb= [IA-64] Number of I/O TLB slabs
  1389. switches= [HW,M68k]
  1390. sym53c416= [HW,SCSI]
  1391. See header of drivers/scsi/sym53c416.c.
  1392. sysrq_always_enabled
  1393. [KNL]
  1394. Ignore sysrq setting - this boot parameter will
  1395. neutralize any effect of /proc/sys/kernel/sysrq.
  1396. Useful for debugging.
  1397. t128= [HW,SCSI]
  1398. See header of drivers/scsi/t128.c.
  1399. tdfx= [HW,DRM]
  1400. thash_entries= [KNL,NET]
  1401. Set number of hash buckets for TCP connection
  1402. thermal.act= [HW,ACPI]
  1403. -1: disable all active trip points in all thermal zones
  1404. <degrees C>: override all lowest active trip points
  1405. thermal.crt= [HW,ACPI]
  1406. -1: disable all critical trip points in all thermal zones
  1407. <degrees C>: lower all critical trip points
  1408. thermal.nocrt= [HW,ACPI]
  1409. Set to disable actions on ACPI thermal zone
  1410. critical and hot trip points.
  1411. thermal.off= [HW,ACPI]
  1412. 1: disable ACPI thermal control
  1413. thermal.psv= [HW,ACPI]
  1414. -1: disable all passive trip points
  1415. <degrees C>: override all passive trip points to this value
  1416. thermal.tzp= [HW,ACPI]
  1417. Specify global default ACPI thermal zone polling rate
  1418. <deci-seconds>: poll all this frequency
  1419. 0: no polling (default)
  1420. time Show timing data prefixed to each printk message line
  1421. [deprecated, see 'printk.time']
  1422. tipar.timeout= [HW,PPT]
  1423. Set communications timeout in tenths of a second
  1424. (default 15).
  1425. tipar.delay= [HW,PPT]
  1426. Set inter-bit delay in microseconds (default 10).
  1427. tmc8xx= [HW,SCSI]
  1428. See header of drivers/scsi/seagate.c.
  1429. tmscsim= [HW,SCSI]
  1430. See comment before function dc390_setup() in
  1431. drivers/scsi/tmscsim.c.
  1432. tp720= [HW,PS2]
  1433. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1434. Format:
  1435. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1436. turbografx.map[2|3]= [HW,JOY]
  1437. TurboGraFX parallel port interface
  1438. Format:
  1439. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1440. See also Documentation/input/joystick-parport.txt
  1441. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1442. See header of drivers/scsi/u14-34f.c.
  1443. uart401= [HW,OSS]
  1444. Format: <io>,<irq>
  1445. uart6850= [HW,OSS]
  1446. Format: <io>,<irq>
  1447. uhci-hcd.ignore_oc=
  1448. [USB] Ignore overcurrent events (default N).
  1449. Some badly-designed motherboards generate lots of
  1450. bogus events, for ports that aren't wired to
  1451. anything. Set this parameter to avoid log spamming.
  1452. Note that genuine overcurrent events won't be
  1453. reported either.
  1454. usbcore.autosuspend=
  1455. [USB] The autosuspend time delay (in seconds) used
  1456. for newly-detected USB devices (default 2). This
  1457. is the time required before an idle device will be
  1458. autosuspended. Devices for which the delay is set
  1459. to a negative value won't be autosuspended at all.
  1460. usbhid.mousepoll=
  1461. [USBHID] The interval which mice are to be polled at.
  1462. vdso= [X86-32,SH,x86-64]
  1463. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1464. vdso=1: enable VDSO (default)
  1465. vdso=0: disable VDSO mapping
  1466. vector= [IA-64,SMP]
  1467. vector=percpu: enable percpu vector domain
  1468. video= [FB] Frame buffer configuration
  1469. See Documentation/fb/modedb.txt.
  1470. vga= [BOOT,X86-32] Select a particular video mode
  1471. See Documentation/i386/boot.txt and
  1472. Documentation/svga.txt.
  1473. Use vga=ask for menu.
  1474. This is actually a boot loader parameter; the value is
  1475. passed to the kernel using a special protocol.
  1476. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1477. size of <nn>. This can be used to increase the
  1478. minimum size (128MB on x86). It can also be used to
  1479. decrease the size and leave more room for directly
  1480. mapped kernel RAM.
  1481. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1482. Format: <command>
  1483. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1484. Format: <command>
  1485. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1486. Format: <command>
  1487. waveartist= [HW,OSS]
  1488. Format: <io>,<irq>,<dma>,<dma2>
  1489. wd33c93= [HW,SCSI]
  1490. See header of drivers/scsi/wd33c93.c.
  1491. wd7000= [HW,SCSI]
  1492. See header of drivers/scsi/wd7000.c.
  1493. wdt= [WDT] Watchdog
  1494. See Documentation/watchdog/wdt.txt.
  1495. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1496. xd_geo= See header of drivers/block/xd.c.
  1497. xirc2ps_cs= [NET,PCMCIA]
  1498. Format:
  1499. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1500. norandmaps Don't use address space randomization
  1501. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1502. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1503. This is useful to get more information why
  1504. you got a "dwarf2 unwinder stuck"
  1505. ______________________________________________________________________
  1506. TODO:
  1507. Add documentation for ALSA options.
  1508. Add more DRM drivers.