kernel-parameters.txt 62 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. ROOTPLUG The example Root Plug LSM is enabled.
  71. S390 S390 architecture is enabled.
  72. SCSI Appropriate SCSI support is enabled.
  73. A lot of drivers has their options described inside of
  74. Documentation/scsi/.
  75. SECURITY Different security models are enabled.
  76. SELINUX SELinux support is enabled.
  77. SERIAL Serial support is enabled.
  78. SH SuperH architecture is enabled.
  79. SMP The kernel is an SMP kernel.
  80. SPARC Sparc architecture is enabled.
  81. SWSUSP Software suspend is enabled.
  82. TS Appropriate touchscreen support is enabled.
  83. USB USB support is enabled.
  84. USBHID USB Human Interface Device support is enabled.
  85. V4L Video For Linux support is enabled.
  86. VGA The VGA console has been enabled.
  87. VT Virtual terminal support is enabled.
  88. WDT Watchdog support is enabled.
  89. XT IBM PC/XT MFM hard disk support is enabled.
  90. X86-32 X86-32, aka i386 architecture is enabled.
  91. X86-64 X86-64 architecture is enabled.
  92. More X86-64 boot options can be found in
  93. Documentation/x86_64/boot-options.txt .
  94. In addition, the following text indicates that the option:
  95. BUGS= Relates to possible processor bugs on the said processor.
  96. KNL Is a kernel start-up parameter.
  97. BOOT Is a boot loader parameter.
  98. Parameters denoted with BOOT are actually interpreted by the boot
  99. loader, and have no meaning to the kernel directly.
  100. Do not modify the syntax of boot loader parameters without extreme
  101. need or coordination with <Documentation/i386/boot.txt>.
  102. There are also arch-specific kernel-parameters not documented here.
  103. See for example <Documentation/x86_64/boot-options.txt>.
  104. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  105. a trailing = on the name of any parameter states that that parameter will
  106. be entered as an environment variable, whereas its absence indicates that
  107. it will appear as a kernel argument readable via /proc/cmdline by programs
  108. running once the system is up.
  109. The number of kernel parameters is not limited, but the length of the
  110. complete command line (parameters including spaces etc.) is limited to
  111. a fixed number of characters. This limit depends on the architecture
  112. and is between 256 and 4096 characters. It is defined in the file
  113. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  114. acpi= [HW,ACPI,X86-64,i386]
  115. Advanced Configuration and Power Interface
  116. Format: { force | off | ht | strict | noirq }
  117. force -- enable ACPI if default was off
  118. off -- disable ACPI if default was on
  119. noirq -- do not use ACPI for IRQ routing
  120. ht -- run only enough ACPI to enable Hyper Threading
  121. strict -- Be less tolerant of platforms that are not
  122. strictly ACPI specification compliant.
  123. See also Documentation/pm.txt, pci=noacpi
  124. acpi_apic_instance= [ACPI, IOAPIC]
  125. Format: <int>
  126. 2: use 2nd APIC table, if available
  127. 1,0: use 1st APIC table
  128. default: 0
  129. acpi_sleep= [HW,ACPI] Sleep options
  130. Format: { s3_bios, s3_mode }
  131. See Documentation/power/video.txt
  132. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  133. Format: { level | edge | high | low }
  134. acpi_irq_balance [HW,ACPI]
  135. ACPI will balance active IRQs
  136. default in APIC mode
  137. acpi_irq_nobalance [HW,ACPI]
  138. ACPI will not move active IRQs (default)
  139. default in PIC mode
  140. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  141. use by PCI
  142. Format: <irq>,<irq>...
  143. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  144. Format: <irq>,<irq>...
  145. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  146. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  147. Format: To spoof as Windows 98: ="Microsoft Windows"
  148. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  149. acpi_osi="string1" # add string1 -- only one string
  150. acpi_osi="!string2" # remove built-in string2
  151. acpi_osi= # disable all strings
  152. acpi_serialize [HW,ACPI] force serialization of AML methods
  153. acpi_skip_timer_override [HW,ACPI]
  154. Recognize and ignore IRQ0/pin2 Interrupt Override.
  155. For broken nForce2 BIOS resulting in XT-PIC timer.
  156. acpi_use_timer_override [HW,ACPI}
  157. Use timer override. For some broken Nvidia NF5 boards
  158. that require a timer override, but don't have
  159. HPET
  160. acpi.debug_layer= [HW,ACPI]
  161. Format: <int>
  162. Each bit of the <int> indicates an ACPI debug layer,
  163. 1: enable, 0: disable. It is useful for boot time
  164. debugging. After system has booted up, it can be set
  165. via /sys/module/acpi/parameters/debug_layer.
  166. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  167. Available bits (add the numbers together) to enable debug output
  168. for specific parts of the ACPI subsystem:
  169. 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
  170. 0x10 namespace 0x20 parser 0x40 dispatcher
  171. 0x80 executer 0x100 resources 0x200 acpica debugger
  172. 0x400 os services 0x800 acpica disassembler.
  173. The number can be in decimal or prefixed with 0x in hex.
  174. Warning: Many of these options can produce a lot of
  175. output and make your system unusable. Be very careful.
  176. acpi.debug_level= [HW,ACPI]
  177. Format: <int>
  178. Each bit of the <int> indicates an ACPI debug level,
  179. 1: enable, 0: disable. It is useful for boot time
  180. debugging. After system has booted up, it can be set
  181. via /sys/module/acpi/parameters/debug_level.
  182. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  183. Available bits (add the numbers together) to enable different
  184. debug output levels of the ACPI subsystem:
  185. 0x01 error 0x02 warn 0x04 init 0x08 debug object
  186. 0x10 info 0x20 init names 0x40 parse 0x80 load
  187. 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
  188. 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
  189. 0x10000 resources 0x20000 user requests 0x40000 package.
  190. The number can be in decimal or prefixed with 0x in hex.
  191. Warning: Many of these options can produce a lot of
  192. output and make your system unusable. Be very careful.
  193. acpi_pm_good [X86-32,X86-64]
  194. Override the pmtimer bug detection: force the kernel
  195. to assume that this machine's pmtimer latches its value
  196. and always returns good values.
  197. agp= [AGP]
  198. { off | try_unsupported }
  199. off: disable AGP support
  200. try_unsupported: try to drive unsupported chipsets
  201. (may crash computer or cause data corruption)
  202. enable_timer_pin_1 [i386,x86-64]
  203. Enable PIN 1 of APIC timer
  204. Can be useful to work around chipset bugs
  205. (in particular on some ATI chipsets).
  206. The kernel tries to set a reasonable default.
  207. disable_timer_pin_1 [i386,x86-64]
  208. Disable PIN 1 of APIC timer
  209. Can be useful to work around chipset bugs.
  210. ad1848= [HW,OSS]
  211. Format: <io>,<irq>,<dma>,<dma2>,<type>
  212. advansys= [HW,SCSI]
  213. See header of drivers/scsi/advansys.c.
  214. advwdt= [HW,WDT] Advantech WDT
  215. Format: <iostart>,<iostop>
  216. aedsp16= [HW,OSS] Audio Excel DSP 16
  217. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  218. See also header of sound/oss/aedsp16.c.
  219. aha152x= [HW,SCSI]
  220. See Documentation/scsi/aha152x.txt.
  221. aha1542= [HW,SCSI]
  222. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  223. aic7xxx= [HW,SCSI]
  224. See Documentation/scsi/aic7xxx.txt.
  225. aic79xx= [HW,SCSI]
  226. See Documentation/scsi/aic79xx.txt.
  227. amijoy.map= [HW,JOY] Amiga joystick support
  228. Map of devices attached to JOY0DAT and JOY1DAT
  229. Format: <a>,<b>
  230. See also Documentation/kernel/input/joystick.txt
  231. analog.map= [HW,JOY] Analog joystick and gamepad support
  232. Specifies type or capabilities of an analog joystick
  233. connected to one of 16 gameports
  234. Format: <type1>,<type2>,..<type16>
  235. apc= [HW,SPARC]
  236. Power management functions (SPARCstation-4/5 + deriv.)
  237. Format: noidle
  238. Disable APC CPU standby support. SPARCstation-Fox does
  239. not play well with APC CPU idle - disable it if you have
  240. APC and your system crashes randomly.
  241. apic= [APIC,i386] Advanced Programmable Interrupt Controller
  242. Change the output verbosity whilst booting
  243. Format: { quiet (default) | verbose | debug }
  244. Change the amount of debugging information output
  245. when initialising the APIC and IO-APIC components.
  246. apm= [APM] Advanced Power Management
  247. See header of arch/i386/kernel/apm.c.
  248. applicom= [HW]
  249. Format: <mem>,<irq>
  250. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  251. Format: <io>,<irq>,<nodeID>
  252. ataflop= [HW,M68k]
  253. atarimouse= [HW,MOUSE] Atari Mouse
  254. atascsi= [HW,SCSI] Atari SCSI
  255. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  256. EzKey and similar keyboards
  257. atkbd.reset= [HW] Reset keyboard during initialization
  258. atkbd.set= [HW] Select keyboard code set
  259. Format: <int> (2 = AT (default), 3 = PS/2)
  260. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  261. keyboards
  262. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  263. Format: <bool> (0 = real, 1 = synthetic (default))
  264. atkbd.softrepeat= [HW]
  265. Use software keyboard repeat
  266. autotest [IA64]
  267. baycom_epp= [HW,AX25]
  268. Format: <io>,<mode>
  269. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  270. Format: <io>,<mode>
  271. See header of drivers/net/hamradio/baycom_par.c.
  272. baycom_ser_fdx= [HW,AX25]
  273. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  274. Format: <io>,<irq>,<mode>[,<baud>]
  275. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  276. baycom_ser_hdx= [HW,AX25]
  277. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  278. Format: <io>,<irq>,<mode>
  279. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  280. blkmtd_device= [HW,MTD]
  281. blkmtd_erasesz=
  282. blkmtd_ro=
  283. blkmtd_bs=
  284. blkmtd_count=
  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. chandev= [HW,NET] Generic channel device initialisation
  310. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  311. Format: { "0" | "1" }
  312. See security/selinux/Kconfig help text.
  313. 0 -- check protection applied by kernel (includes
  314. any implied execute protection).
  315. 1 -- check protection requested by application.
  316. Default value is set via a kernel config option.
  317. Value can be changed at runtime via
  318. /selinux/checkreqprot.
  319. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  320. [Deprecated]
  321. Forces specified clocksource (if available) to be used
  322. when calculating gettimeofday(). If specified
  323. clocksource is not available, it defaults to PIT.
  324. Format: { pit | tsc | cyclone | pmtmr }
  325. clocksource= [GENERIC_TIME] Override the default clocksource
  326. Format: <string>
  327. Override the default clocksource and use the clocksource
  328. with the name specified.
  329. Some clocksource names to choose from, depending on
  330. the platform:
  331. [all] jiffies (this is the base, fallback clocksource)
  332. [ACPI] acpi_pm
  333. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  334. pxa_timer,timer3,32k_counter,timer0_1
  335. [AVR32] avr32
  336. [X86-32] pit,hpet,tsc,vmi-timer;
  337. scx200_hrt on Geode; cyclone on IBM x440
  338. [MIPS] MIPS
  339. [PARISC] cr16
  340. [S390] tod
  341. [SH] SuperH
  342. [SPARC64] tick
  343. [X86-64] hpet,tsc
  344. code_bytes [IA32] How many bytes of object code to print in an
  345. oops report.
  346. Range: 0 - 8192
  347. Default: 64
  348. disable_8254_timer
  349. enable_8254_timer
  350. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  351. over the 8254 in addition to over the IO-APIC. The
  352. kernel tries to set a sensible default.
  353. hpet= [X86-32,HPET] option to disable HPET and use PIT.
  354. Format: disable
  355. com20020= [HW,NET] ARCnet - COM20020 chipset
  356. Format:
  357. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  358. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  359. Format: <io>[,<irq>]
  360. com90xx= [HW,NET]
  361. ARCnet - COM90xx chipset (memory-mapped buffers)
  362. Format: <io>[,<irq>[,<memstart>]]
  363. condev= [HW,S390] console device
  364. conmode=
  365. console= [KNL] Output console device and options.
  366. tty<n> Use the virtual console device <n>.
  367. ttyS<n>[,options]
  368. ttyUSB0[,options]
  369. Use the specified serial port. The options are of
  370. the form "bbbbpnf", where "bbbb" is the baud rate,
  371. "p" is parity ("n", "o", or "e"), "n" is number of
  372. bits, and "f" is flow control ("r" for RTS or
  373. omit it). Default is "9600n8".
  374. See Documentation/serial-console.txt for more
  375. information. See
  376. Documentation/networking/netconsole.txt for an
  377. alternative.
  378. uart[8250],io,<addr>[,options]
  379. uart[8250],mmio,<addr>[,options]
  380. Start an early, polled-mode console on the 8250/16550
  381. UART at the specified I/O port or MMIO address,
  382. switching to the matching ttyS device later. The
  383. options are the same as for ttyS, above.
  384. earlycon= [KNL] Output early console device and options.
  385. uart[8250],io,<addr>[,options]
  386. uart[8250],mmio,<addr>[,options]
  387. Start an early, polled-mode console on the 8250/16550
  388. UART at the specified I/O port or MMIO address.
  389. The options are the same as for ttyS, above.
  390. no_console_suspend
  391. [HW] Never suspend the console
  392. Disable suspending of consoles during suspend and
  393. hibernate operations. Once disabled, debugging
  394. messages can reach various consoles while the rest
  395. of the system is being put to sleep (ie, while
  396. debugging driver suspend/resume hooks). This may
  397. not work reliably with all consoles, but is known
  398. to work with serial and VGA consoles.
  399. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  400. Format:
  401. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  402. crashkernel=nn[KMG]@ss[KMG]
  403. [KNL] Reserve a chunk of physical memory to
  404. hold a kernel to switch to with kexec on panic.
  405. crashkernel=range1:size1[,range2:size2,...][@offset]
  406. [KNL] Same as above, but depends on the memory
  407. in the running system. The syntax of range is
  408. start-[end] where start and end are both
  409. a memory unit (amount[KMG]). See also
  410. Documentation/kdump/kdump.txt for a example.
  411. cs4232= [HW,OSS]
  412. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  413. cs89x0_dma= [HW,NET]
  414. Format: <dma>
  415. cs89x0_media= [HW,NET]
  416. Format: { rj45 | aui | bnc }
  417. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  418. dasd= [HW,NET]
  419. See header of drivers/s390/block/dasd_devmap.c.
  420. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  421. (one device per port)
  422. Format: <port#>,<type>
  423. See also Documentation/input/joystick-parport.txt
  424. debug [KNL] Enable kernel debugging (events log level).
  425. debug_locks_verbose=
  426. [KNL] verbose self-tests
  427. Format=<0|1>
  428. Print debugging info while doing the locking API
  429. self-tests.
  430. We default to 0 (no extra messages), setting it to
  431. 1 will print _a lot_ more information - normally
  432. only useful to kernel developers.
  433. decnet= [HW,NET]
  434. Format: <area>[,<node>]
  435. See also Documentation/networking/decnet.txt.
  436. default_blu= [VT]
  437. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  438. Change the default blue palette of the console.
  439. This is a 16-member array composed of values
  440. ranging from 0-255.
  441. default_grn= [VT]
  442. Format: <green0>,<green1>,<green2>,...,<green15>
  443. Change the default green palette of the console.
  444. This is a 16-member array composed of values
  445. ranging from 0-255.
  446. default_red= [VT]
  447. Format: <red0>,<red1>,<red2>,...,<red15>
  448. Change the default red palette of the console.
  449. This is a 16-member array composed of values
  450. ranging from 0-255.
  451. default_utf8= [VT]
  452. Format=<0|1>
  453. Set system-wide default UTF-8 mode for all tty's.
  454. Default is 0 and by setting to 1, it enables UTF-8
  455. mode for all newly opened or allocated terminals.
  456. dhash_entries= [KNL]
  457. Set number of hash buckets for dentry cache.
  458. digi= [HW,SERIAL]
  459. IO parameters + enable/disable command.
  460. digiepca= [HW,SERIAL]
  461. See drivers/char/README.epca and
  462. Documentation/digiepca.txt.
  463. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  464. support available.
  465. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  466. dmasound= [HW,OSS] Sound subsystem buffers
  467. dscc4.setup= [NET]
  468. dtc3181e= [HW,SCSI]
  469. earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
  470. earlyprintk=vga
  471. earlyprintk=serial[,ttySn[,baudrate]]
  472. Append ",keep" to not disable it when the real console
  473. takes over.
  474. Only vga or serial at a time, not both.
  475. Currently only ttyS0 and ttyS1 are supported.
  476. Interaction with the standard serial driver is not
  477. very good.
  478. The VGA output is eventually overwritten by the real
  479. console.
  480. eata= [HW,SCSI]
  481. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  482. Format: <int>
  483. 0: polling mode
  484. non-0: interrupt mode (default)
  485. eda= [HW,PS2]
  486. edb= [HW,PS2]
  487. edd= [EDD]
  488. Format: {"of[f]" | "sk[ipmbr]"}
  489. See comment in arch/i386/boot/edd.S
  490. eisa_irq_edge= [PARISC,HW]
  491. See header of drivers/parisc/eisa.c.
  492. elanfreq= [X86-32]
  493. See comment before function elanfreq_setup() in
  494. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  495. elevator= [IOSCHED]
  496. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  497. See Documentation/block/as-iosched.txt and
  498. Documentation/block/deadline-iosched.txt for details.
  499. elfcorehdr= [X86-32, X86_64]
  500. Specifies physical address of start of kernel core
  501. image elf header. Generally kexec loader will
  502. pass this option to capture kernel.
  503. See Documentation/kdump/kdump.txt for details.
  504. enforcing [SELINUX] Set initial enforcing status.
  505. Format: {"0" | "1"}
  506. See security/selinux/Kconfig help text.
  507. 0 -- permissive (log only, no denials).
  508. 1 -- enforcing (deny and log).
  509. Default value is 0.
  510. Value can be changed at runtime via /selinux/enforce.
  511. es1371= [HW,OSS]
  512. Format: <spdif>,[<nomix>,[<amplifier>]]
  513. See also header of sound/oss/es1371.c.
  514. ether= [HW,NET] Ethernet cards parameters
  515. This option is obsoleted by the "netdev=" option, which
  516. has equivalent usage. See its documentation for details.
  517. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  518. Format: <io>[,<irq>]
  519. failslab=
  520. fail_page_alloc=
  521. fail_make_request=[KNL]
  522. General fault injection mechanism.
  523. Format: <interval>,<probability>,<space>,<times>
  524. See also /Documentation/fault-injection/.
  525. fd_mcs= [HW,SCSI]
  526. See header of drivers/scsi/fd_mcs.c.
  527. fdomain= [HW,SCSI]
  528. See header of drivers/scsi/fdomain.c.
  529. floppy= [HW]
  530. See Documentation/floppy.txt.
  531. gamecon.map[2|3]=
  532. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  533. support via parallel port (up to 5 devices per port)
  534. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  535. See also Documentation/input/joystick-parport.txt
  536. gamma= [HW,DRM]
  537. gdth= [HW,SCSI]
  538. See header of drivers/scsi/gdth.c.
  539. gpt [EFI] Forces disk with valid GPT signature but
  540. invalid Protective MBR to be treated as GPT.
  541. gvp11= [HW,SCSI]
  542. hashdist= [KNL,NUMA] Large hashes allocated during boot
  543. are distributed across NUMA nodes. Defaults on
  544. for IA-64, off otherwise.
  545. Format: 0 | 1 (for off | on)
  546. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  547. hd= [EIDE] (E)IDE hard drive subsystem geometry
  548. Format: <cyl>,<head>,<sect>
  549. hd?= [HW] (E)IDE subsystem
  550. hd?lun= See Documentation/ide.txt.
  551. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  552. size of <nn>. This works even on boxes that have no
  553. highmem otherwise. This also works to reduce highmem
  554. size on bigger boxes.
  555. highres= [KNL] Enable/disable high resolution timer mode.
  556. Valid parameters: "on", "off"
  557. Default: "on"
  558. hisax= [HW,ISDN]
  559. See Documentation/isdn/README.HiSax.
  560. hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
  561. i8042.direct [HW] Put keyboard port into non-translated mode
  562. i8042.dumbkbd [HW] Pretend that controller can only read data from
  563. keyboard and cannot control its state
  564. (Don't attempt to blink the leds)
  565. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  566. i8042.nokbd [HW] Don't check/create keyboard port
  567. i8042.nomux [HW] Don't check presence of an active multiplexing
  568. controller
  569. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  570. controllers
  571. i8042.panicblink=
  572. [HW] Frequency with which keyboard LEDs should blink
  573. when kernel panics (default is 0.5 sec)
  574. i8042.reset [HW] Reset the controller during init and cleanup
  575. i8042.unlock [HW] Unlock (ignore) the keylock
  576. i810= [HW,DRM]
  577. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  578. indicates that the driver is running on unsupported
  579. hardware.
  580. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  581. does not match list of supported models.
  582. i8k.power_status
  583. [HW] Report power status in /proc/i8k
  584. (disabled by default)
  585. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  586. capability is set.
  587. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  588. See Documentation/mca.txt.
  589. icn= [HW,ISDN]
  590. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  591. ide= [HW] (E)IDE subsystem
  592. Format: ide=nodma or ide=doubler or ide=reverse
  593. See Documentation/ide.txt.
  594. ide?= [HW] (E)IDE subsystem
  595. Format: ide?=noprobe or chipset specific parameters.
  596. See Documentation/ide.txt.
  597. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  598. See Documentation/ide.txt.
  599. idle= [X86]
  600. Format: idle=poll or idle=mwait
  601. Poll forces a polling idle loop that can slightly improves the performance
  602. of waking up a idle CPU, but will use a lot of power and make the system
  603. run hot. Not recommended.
  604. idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
  605. to not use it because it doesn't save as much power as a normal idle
  606. loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
  607. as idle=poll.
  608. ignore_loglevel [KNL]
  609. Ignore loglevel setting - this will print /all/
  610. kernel messages to the console. Useful for debugging.
  611. ihash_entries= [KNL]
  612. Set number of hash buckets for inode cache.
  613. in2000= [HW,SCSI]
  614. See header of drivers/scsi/in2000.c.
  615. init= [KNL]
  616. Format: <full_path>
  617. Run specified binary instead of /sbin/init as init
  618. process.
  619. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  620. for working out where the kernel is dying during
  621. startup.
  622. initrd= [BOOT] Specify the location of the initial ramdisk
  623. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  624. Format: <irq>
  625. inttest= [IA64]
  626. io7= [HW] IO7 for Marvel based alpha systems
  627. See comment before marvel_specify_io7 in
  628. arch/alpha/kernel/core_marvel.c.
  629. ip= [IP_PNP]
  630. See Documentation/nfsroot.txt.
  631. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  632. See comment before ip2_setup() in
  633. drivers/char/ip2/ip2base.c.
  634. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  635. See header of drivers/scsi/ips.c.
  636. ports= [IP_VS_FTP] IPVS ftp helper module
  637. Default is 21.
  638. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  639. may be specified.
  640. Format: <port>,<port>....
  641. irqfixup [HW]
  642. When an interrupt is not handled search all handlers
  643. for it. Intended to get systems with badly broken
  644. firmware running.
  645. irqpoll [HW]
  646. When an interrupt is not handled search all handlers
  647. for it. Also check all handlers each timer
  648. interrupt. Intended to get systems with badly broken
  649. firmware running.
  650. isapnp= [ISAPNP]
  651. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  652. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  653. Format:
  654. <cpu number>,...,<cpu number>
  655. or
  656. <cpu number>-<cpu number> (must be a positive range in ascending order)
  657. or a mixture
  658. <cpu number>,...,<cpu number>-<cpu number>
  659. This option can be used to specify one or more CPUs
  660. to isolate from the general SMP balancing and scheduling
  661. algorithms. The only way to move a process onto or off
  662. an "isolated" CPU is via the CPU affinity syscalls.
  663. <cpu number> begins at 0 and the maximum value is
  664. "number of CPUs in system - 1".
  665. This option is the preferred way to isolate CPUs. The
  666. alternative -- manually setting the CPU mask of all
  667. tasks in the system -- can cause problems and
  668. suboptimal load balancer performance.
  669. iucv= [HW,NET]
  670. js= [HW,JOY] Analog joystick
  671. See Documentation/input/joystick.txt.
  672. kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  673. specifies the amount of memory usable by the kernel
  674. for non-movable allocations. The requested amount is
  675. spread evenly throughout all nodes in the system. The
  676. remaining memory in each node is used for Movable
  677. pages. In the event, a node is too small to have both
  678. kernelcore and Movable pages, kernelcore pages will
  679. take priority and other nodes will have a larger number
  680. of kernelcore pages. The Movable zone is used for the
  681. allocation of pages that may be reclaimed or moved
  682. by the page migration subsystem. This means that
  683. HugeTLB pages may not be allocated from this zone.
  684. Note that allocations like PTEs-from-HighMem still
  685. use the HighMem zone if it exists, and the Normal
  686. zone if it does not.
  687. movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
  688. is similar to kernelcore except it specifies the
  689. amount of memory used for migratable allocations.
  690. If both kernelcore and movablecore is specified,
  691. then kernelcore will be at *least* the specified
  692. value but may be more. If movablecore on its own
  693. is specified, the administrator must be careful
  694. that the amount of memory usable for all allocations
  695. is not too small.
  696. keepinitrd [HW,ARM]
  697. kstack=N [X86-32,X86-64] Print N words from the kernel stack
  698. in oops dumps.
  699. l2cr= [PPC]
  700. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  701. disabled it.
  702. lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
  703. C2 power state.
  704. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  705. when set.
  706. Format: <int>
  707. load_ramdisk= [RAM] List of ramdisks to load from floppy
  708. See Documentation/ramdisk.txt.
  709. lockd.nlm_grace_period=P [NFS] Assign grace period.
  710. Format: <integer>
  711. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  712. Format: <integer>
  713. lockd.nlm_timeout=T [NFS] Assign timeout value.
  714. Format: <integer>
  715. lockd.nlm_udpport=M [NFS] Assign UDP port.
  716. Format: <integer>
  717. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  718. Format: <irq>
  719. loglevel= All Kernel Messages with a loglevel smaller than the
  720. console loglevel will be printed to the console. It can
  721. also be changed with klogd or other programs. The
  722. loglevels are defined as follows:
  723. 0 (KERN_EMERG) system is unusable
  724. 1 (KERN_ALERT) action must be taken immediately
  725. 2 (KERN_CRIT) critical conditions
  726. 3 (KERN_ERR) error conditions
  727. 4 (KERN_WARNING) warning conditions
  728. 5 (KERN_NOTICE) normal but significant condition
  729. 6 (KERN_INFO) informational
  730. 7 (KERN_DEBUG) debug-level messages
  731. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  732. Format: { n | nk | nM }
  733. n must be a power of two. The default size
  734. is set in the kernel config file.
  735. logo.nologo [FB] Disables display of the built-in Linux logo.
  736. This may be used to provide more screen space for
  737. kernel log messages and is useful when debugging
  738. kernel boot problems.
  739. lp=0 [LP] Specify parallel ports to use, e.g,
  740. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  741. lp=reset first parallel port). 'lp=0' disables the
  742. lp=auto printer driver. 'lp=reset' (which can be
  743. specified in addition to the ports) causes
  744. attached printers to be reset. Using
  745. lp=port1,port2,... specifies the parallel ports
  746. to associate lp devices with, starting with
  747. lp0. A port specification may be 'none' to skip
  748. that lp device, or a parport name such as
  749. 'parport0'. Specifying 'lp=auto' instead of a
  750. port specification list means that device IDs
  751. from each port should be examined, to see if
  752. an IEEE 1284-compliant printer is attached; if
  753. so, the driver will manage that printer.
  754. See also header of drivers/char/lp.c.
  755. lpj=n [KNL]
  756. Sets loops_per_jiffy to given constant, thus avoiding
  757. time-consuming boot-time autodetection (up to 250 ms per
  758. CPU). 0 enables autodetection (default). To determine
  759. the correct value for your kernel, boot with normal
  760. autodetection and see what value is printed. Note that
  761. on SMP systems the preset will be applied to all CPUs,
  762. which is likely to cause problems if your CPUs need
  763. significantly divergent settings. An incorrect value
  764. will cause delays in the kernel to be wrong, leading to
  765. unpredictable I/O errors and other breakage. Although
  766. unlikely, in the extreme case this might damage your
  767. hardware.
  768. ltpc= [NET]
  769. Format: <io>,<irq>,<dma>
  770. mac5380= [HW,SCSI] Format:
  771. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  772. mac53c9x= [HW,SCSI] Format:
  773. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  774. machvec= [IA64] Force the use of a particular machine-vector
  775. (machvec) in a generic kernel.
  776. Example: machvec=hpzx1_swiotlb
  777. max_loop= [LOOP] Maximum number of loopback devices that can
  778. be mounted
  779. Format: <1-256>
  780. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  781. should make use of. maxcpus=n : n >= 0 limits the
  782. kernel to using 'n' processors. n=0 is a special case,
  783. it is equivalent to "nosmp", which also disables
  784. the IO APIC.
  785. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  786. equal to this physical address is ignored.
  787. max_luns= [SCSI] Maximum number of LUNs to probe.
  788. Should be between 1 and 2^32-1.
  789. max_report_luns=
  790. [SCSI] Maximum number of LUNs received.
  791. Should be between 1 and 16384.
  792. mca-pentium [BUGS=X86-32]
  793. mcatest= [IA-64]
  794. mce [X86-32] Machine Check Exception
  795. mce=option [X86-64] See Documentation/x86_64/boot-options.txt
  796. md= [HW] RAID subsystems devices and level
  797. See Documentation/md.txt.
  798. mdacon= [MDA]
  799. Format: <first>,<last>
  800. Specifies range of consoles to be captured by the MDA.
  801. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  802. Amount of memory to be used when the kernel is not able
  803. to see the whole system memory or for test.
  804. [X86-32] Use together with memmap= to avoid physical
  805. address space collisions. Without memmap= PCI devices
  806. could be placed at addresses belonging to unused RAM.
  807. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  808. memory.
  809. memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
  810. E820 memory map, as specified by the user.
  811. Such memmap=exactmap lines can be constructed based on
  812. BIOS output or other requirements. See the memmap=nn@ss
  813. option description.
  814. memmap=nn[KMG]@ss[KMG]
  815. [KNL] Force usage of a specific region of memory
  816. Region of memory to be used, from ss to ss+nn.
  817. memmap=nn[KMG]#ss[KMG]
  818. [KNL,ACPI] Mark specific memory as ACPI data.
  819. Region of memory to be used, from ss to ss+nn.
  820. memmap=nn[KMG]$ss[KMG]
  821. [KNL,ACPI] Mark specific memory as reserved.
  822. Region of memory to be used, from ss to ss+nn.
  823. meye.*= [HW] Set MotionEye Camera parameters
  824. See Documentation/video4linux/meye.txt.
  825. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  826. Multi-Function General Purpose Timers on AMD Geode
  827. platforms.
  828. mga= [HW,DRM]
  829. mousedev.tap_time=
  830. [MOUSE] Maximum time between finger touching and
  831. leaving touchpad surface for touch to be considered
  832. a tap and be reported as a left button click (for
  833. touchpads working in absolute mode only).
  834. Format: <msecs>
  835. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  836. reporting absolute coordinates, such as tablets
  837. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  838. reporting absolute coordinates, such as tablets
  839. mpu401= [HW,OSS]
  840. Format: <io>,<irq>
  841. MTD_Partition= [MTD]
  842. Format: <name>,<region-number>,<size>,<offset>
  843. MTD_Region= [MTD] Format:
  844. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  845. mtdparts= [MTD]
  846. See drivers/mtd/cmdlinepart.c.
  847. mtouchusb.raw_coordinates=
  848. [HW] Make the MicroTouch USB driver use raw coordinates
  849. ('y', default) or cooked coordinates ('n')
  850. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  851. NCR_D700= [HW,SCSI]
  852. See header of drivers/scsi/NCR_D700.c.
  853. ncr5380= [HW,SCSI]
  854. ncr53c400= [HW,SCSI]
  855. ncr53c400a= [HW,SCSI]
  856. ncr53c406a= [HW,SCSI]
  857. ncr53c8xx= [HW,SCSI]
  858. netdev= [NET] Network devices parameters
  859. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  860. Note that mem_start is often overloaded to mean
  861. something different and driver-specific.
  862. This usage is only documented in each driver source
  863. file if at all.
  864. nfsaddrs= [NFS]
  865. See Documentation/nfsroot.txt.
  866. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  867. See Documentation/nfsroot.txt.
  868. nfs.callback_tcpport=
  869. [NFS] set the TCP port on which the NFSv4 callback
  870. channel should listen.
  871. nfs.idmap_cache_timeout=
  872. [NFS] set the maximum lifetime for idmapper cache
  873. entries.
  874. nfs.enable_ino64=
  875. [NFS] enable 64-bit inode numbers.
  876. If zero, the NFS client will fake up a 32-bit inode
  877. number for the readdir() and stat() syscalls instead
  878. of returning the full 64-bit number.
  879. The default is to return 64-bit inode numbers.
  880. nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
  881. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  882. emulation library even if a 387 maths coprocessor
  883. is present.
  884. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  885. caches in the slab allocator. Saves per-node memory,
  886. but will impact performance.
  887. noalign [KNL,ARM]
  888. noapic [SMP,APIC] Tells the kernel to not make use of any
  889. IOAPICs that may be present in the system.
  890. noasync [HW,M68K] Disables async and sync negotiation for
  891. all devices.
  892. nobats [PPC] Do not use BATs for mapping kernel lowmem
  893. on "Classic" PPC cores.
  894. nocache [ARM]
  895. nodelayacct [KNL] Disable per-task delay accounting
  896. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  897. noexec [IA-64]
  898. noexec [X86-32,X86-64]
  899. noexec=on: enable non-executable mappings (default)
  900. noexec=off: disable nn-executable mappings
  901. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  902. register save and restore. The kernel will only save
  903. legacy floating-point registers on task switch.
  904. nohlt [BUGS=ARM]
  905. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  906. instruction doesn't work correctly and not to
  907. use it.
  908. nohalt [IA-64] Tells the kernel not to use the power saving
  909. function PAL_HALT_LIGHT when idle. This increases
  910. power-consumption. On the positive side, it reduces
  911. interrupt wake-up latency, which may improve performance
  912. in certain environments such as networked servers or
  913. real-time systems.
  914. nohz= [KNL] Boottime enable/disable dynamic ticks
  915. Valid arguments: on, off
  916. Default: on
  917. noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
  918. noirqdebug [X86-32] Disables the code which attempts to detect and
  919. disable unhandled interrupt sources.
  920. no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
  921. broken timer IRQ sources.
  922. noisapnp [ISAPNP] Disables ISA PnP code.
  923. noinitrd [RAM] Tells the kernel not to load any configured
  924. initial RAM disk.
  925. nointroute [IA-64]
  926. nojitter [IA64] Disables jitter checking for ITC timers.
  927. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  928. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  929. noltlbs [PPC] Do not use large page/tlb entries for kernel
  930. lowmem mapping on PPC40x.
  931. nomca [IA-64] Disable machine check abort handling
  932. nomce [X86-32] Machine Check Exception
  933. nomfgpt [X86-32] Disable Multi-Function General Purpose
  934. Timer usage (for AMD Geode machines).
  935. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  936. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  937. with UP alternatives
  938. noresidual [PPC] Don't use residual data on PReP machines.
  939. noresume [SWSUSP] Disables resume and restores original swap
  940. space.
  941. no-scroll [VGA] Disables scrollback.
  942. This is required for the Braillex ib80-piezo Braille
  943. reader made by F.H. Papenmeier (Germany).
  944. nosbagart [IA-64]
  945. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  946. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  947. and disable the IO APIC. legacy for "maxcpus=0".
  948. nosoftlockup [KNL] Disable the soft-lockup detector.
  949. nosync [HW,M68K] Disables sync negotiation for all devices.
  950. notsc [BUGS=X86-32] Disable Time Stamp Counter
  951. nousb [USB] Disable the USB subsystem
  952. nowb [ARM]
  953. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  954. one of ['zone', 'node', 'default'] can be specified
  955. This can be set from sysctl after boot.
  956. See Documentation/sysctl/vm.txt for details.
  957. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  958. opl3= [HW,OSS]
  959. Format: <io>
  960. oprofile.timer= [HW]
  961. Use timer interrupt instead of performance counters
  962. osst= [HW,SCSI] SCSI Tape Driver
  963. Format: <buffer_size>,<write_threshold>
  964. See also Documentation/scsi/st.txt.
  965. panic= [KNL] Kernel behaviour on panic
  966. Format: <timeout>
  967. parkbd.port= [HW] Parallel port number the keyboard adapter is
  968. connected to, default is 0.
  969. Format: <parport#>
  970. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  971. 0 for XT, 1 for AT (default is AT).
  972. Format: <mode>
  973. parport= [HW,PPT] Specify parallel ports. 0 disables.
  974. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  975. Use 'auto' to force the driver to use any
  976. IRQ/DMA settings detected (the default is to
  977. ignore detected IRQ/DMA settings because of
  978. possible conflicts). You can specify the base
  979. address, IRQ, and DMA settings; IRQ and DMA
  980. should be numbers, or 'auto' (for using detected
  981. settings on that particular port), or 'nofifo'
  982. (to avoid using a FIFO even if it is detected).
  983. Parallel ports are assigned in the order they
  984. are specified on the command line, starting
  985. with parport0.
  986. parport_init_mode= [HW,PPT]
  987. Configure VIA parallel port to operate in
  988. a specific mode. This is necessary on Pegasos
  989. computer where firmware has no options for setting
  990. up parallel port mode and sets it to spp.
  991. Currently this function knows 686a and 8231 chips.
  992. Format: [spp|ps2|epp|ecp|ecpepp]
  993. pas2= [HW,OSS] Format:
  994. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  995. pas16= [HW,SCSI]
  996. See header of drivers/scsi/pas16.c.
  997. pause_on_oops=
  998. Halt all CPUs after the first oops has been printed for
  999. the specified number of seconds. This is to be used if
  1000. your oopses keep scrolling off the screen.
  1001. pcbit= [HW,ISDN]
  1002. pcd. [PARIDE]
  1003. See header of drivers/block/paride/pcd.c.
  1004. See also Documentation/paride.txt.
  1005. pci=option[,option...] [PCI] various PCI subsystem options:
  1006. off [X86-32] don't probe for the PCI bus
  1007. bios [X86-32] force use of PCI BIOS, don't access
  1008. the hardware directly. Use this if your machine
  1009. has a non-standard PCI host bridge.
  1010. nobios [X86-32] disallow use of PCI BIOS, only direct
  1011. hardware access methods are allowed. Use this
  1012. if you experience crashes upon bootup and you
  1013. suspect they are caused by the BIOS.
  1014. conf1 [X86-32] Force use of PCI Configuration
  1015. Mechanism 1.
  1016. conf2 [X86-32] Force use of PCI Configuration
  1017. Mechanism 2.
  1018. noaer [PCIE] If the PCIEAER kernel config parameter is
  1019. enabled, this kernel boot option can be used to
  1020. disable the use of PCIE advanced error reporting.
  1021. nodomains [PCI] Disable support for multiple PCI
  1022. root domains (aka PCI segments, in ACPI-speak).
  1023. nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
  1024. Configuration
  1025. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1026. enabled, this kernel boot option can be used to
  1027. disable the use of MSI interrupts system-wide.
  1028. nosort [X86-32] Don't sort PCI devices according to
  1029. order given by the PCI BIOS. This sorting is
  1030. done to get a device order compatible with
  1031. older kernels.
  1032. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1033. routing table. These calls are known to be buggy
  1034. on several machines and they hang the machine
  1035. when used, but on other computers it's the only
  1036. way to get the interrupt routing table. Try
  1037. this option if the kernel is unable to allocate
  1038. IRQs or discover secondary PCI buses on your
  1039. motherboard.
  1040. rom [X86-32] Assign address space to expansion ROMs.
  1041. Use with caution as certain devices share
  1042. address decoders between ROMs and other
  1043. resources.
  1044. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
  1045. assigned automatically to PCI devices. You can
  1046. make the kernel exclude IRQs of your ISA cards
  1047. this way.
  1048. pirqaddr=0xAAAAA [X86-32] Specify the physical address
  1049. of the PIRQ table (normally generated
  1050. by the BIOS) if it is outside the
  1051. F0000h-100000h range.
  1052. lastbus=N [X86-32] Scan all buses thru bus #N. Can be
  1053. useful if the kernel is unable to find your
  1054. secondary buses and you want to tell it
  1055. explicitly which ones they are.
  1056. assign-busses [X86-32] Always assign all PCI bus
  1057. numbers ourselves, overriding
  1058. whatever the firmware may have done.
  1059. usepirqmask [X86-32] Honor the possible IRQ mask stored
  1060. in the BIOS $PIR table. This is needed on
  1061. some systems with broken BIOSes, notably
  1062. some HP Pavilion N5400 and Omnibook XE3
  1063. notebooks. This will have no effect if ACPI
  1064. IRQ routing is enabled.
  1065. noacpi [X86-32] Do not use ACPI for IRQ routing
  1066. or for PCI scanning.
  1067. use_crs [X86-32] Use _CRS for PCI resource
  1068. allocation.
  1069. routeirq Do IRQ routing for all PCI devices.
  1070. This is normally done in pci_enable_device(),
  1071. so this option is a temporary workaround
  1072. for broken drivers that don't call it.
  1073. firmware [ARM] Do not re-enumerate the bus but instead
  1074. just use the configuration from the
  1075. bootloader. This is currently used on
  1076. IXP2000 systems where the bus has to be
  1077. configured a certain way for adjunct CPUs.
  1078. noearly [X86] Don't do any early type 1 scanning.
  1079. This might help on some broken boards which
  1080. machine check when some devices' config space
  1081. is read. But various workarounds are disabled
  1082. and some IOMMU drivers will not work.
  1083. bfsort Sort PCI devices into breadth-first order.
  1084. This sorting is done to get a device
  1085. order compatible with older (<= 2.4) kernels.
  1086. nobfsort Don't sort PCI devices into breadth-first order.
  1087. cbiosize=nn[KMG] The fixed amount of bus space which is
  1088. reserved for the CardBus bridge's IO window.
  1089. The default value is 256 bytes.
  1090. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1091. reserved for the CardBus bridge's memory
  1092. window. The default value is 64 megabytes.
  1093. pcmv= [HW,PCMCIA] BadgePAD 4
  1094. pd. [PARIDE]
  1095. See Documentation/paride.txt.
  1096. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1097. boot time.
  1098. Format: { 0 | 1 }
  1099. See arch/parisc/kernel/pdc_chassis.c
  1100. pf. [PARIDE]
  1101. See Documentation/paride.txt.
  1102. pg. [PARIDE]
  1103. See Documentation/paride.txt.
  1104. pirq= [SMP,APIC] Manual mp-table setup
  1105. See Documentation/i386/IO-APIC.txt.
  1106. plip= [PPT,NET] Parallel port network link
  1107. Format: { parport<nr> | timid | 0 }
  1108. See also Documentation/parport.txt.
  1109. pnpacpi= [ACPI]
  1110. { off }
  1111. pnpbios= [ISAPNP]
  1112. { on | off | curr | res | no-curr | no-res }
  1113. pnp_reserve_irq=
  1114. [ISAPNP] Exclude IRQs for the autoconfiguration
  1115. pnp_reserve_dma=
  1116. [ISAPNP] Exclude DMAs for the autoconfiguration
  1117. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1118. Ranges are in pairs (I/O port base and size).
  1119. pnp_reserve_mem=
  1120. [ISAPNP] Exclude memory regions for the
  1121. autoconfiguration.
  1122. Ranges are in pairs (memory base and size).
  1123. print-fatal-signals=
  1124. [KNL] debug: print fatal signals
  1125. print-fatal-signals=1: print segfault info to
  1126. the kernel console.
  1127. default: off.
  1128. printk.time= Show timing data prefixed to each printk message line
  1129. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1130. profile= [KNL] Enable kernel profiling via /proc/profile
  1131. Format: [schedule,]<number>
  1132. Param: "schedule" - profile schedule points.
  1133. Param: <number> - step/bucket size as a power of 2 for
  1134. statistical time based profiling.
  1135. Param: "sleep" - profile D-state sleeping (millisecs)
  1136. processor.max_cstate= [HW,ACPI]
  1137. Limit processor to maximum C-state
  1138. max_cstate=9 overrides any DMI blacklist limit.
  1139. processor.nocst [HW,ACPI]
  1140. Ignore the _CST method to determine C-states,
  1141. instead using the legacy FADT method
  1142. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1143. before loading.
  1144. See Documentation/ramdisk.txt.
  1145. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1146. probe for; one of (bare|imps|exps|lifebook|any).
  1147. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1148. per second.
  1149. psmouse.resetafter= [HW,MOUSE]
  1150. Try to reset the device after so many bad packets
  1151. (0 = never).
  1152. psmouse.resolution=
  1153. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1154. psmouse.smartscroll=
  1155. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1156. 0 = disabled, 1 = enabled (default).
  1157. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1158. Format:
  1159. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1160. pt. [PARIDE]
  1161. See Documentation/paride.txt.
  1162. pty.legacy_count=
  1163. [KNL] Number of legacy pty's. Overwrites compiled-in
  1164. default number.
  1165. quiet [KNL] Disable most log messages
  1166. r128= [HW,DRM]
  1167. raid= [HW,RAID]
  1168. See Documentation/md.txt.
  1169. ramdisk_blocksize= [RAM]
  1170. See Documentation/ramdisk.txt.
  1171. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1172. See Documentation/ramdisk.txt.
  1173. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1174. RCU callbacks to process in one batch.
  1175. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1176. RCU callbacks over which batch limiting is disabled.
  1177. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1178. RCU callbacks below which batch limiting is re-enabled.
  1179. rdinit= [KNL]
  1180. Format: <full_path>
  1181. Run specified binary instead of /init from the ramdisk,
  1182. used for early userspace startup. See initrd.
  1183. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1184. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1185. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1186. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1187. reservetop= [X86-32]
  1188. Format: nn[KMG]
  1189. Reserves a hole at the top of the kernel virtual
  1190. address space.
  1191. reset_devices [KNL] Force drivers to reset the underlying device
  1192. during initialization.
  1193. resume= [SWSUSP]
  1194. Specify the partition device for software suspend
  1195. resume_offset= [SWSUSP]
  1196. Specify the offset from the beginning of the partition
  1197. given by "resume=" at which the swap header is located,
  1198. in <PAGE_SIZE> units (needed only for swap files).
  1199. See Documentation/power/swsusp-and-swap-files.txt
  1200. retain_initrd [RAM] Keep initrd memory after extraction
  1201. rhash_entries= [KNL,NET]
  1202. Set number of hash buckets for route cache
  1203. riscom8= [HW,SERIAL]
  1204. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1205. ro [KNL] Mount root device read-only on boot
  1206. root= [KNL] Root filesystem
  1207. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1208. mount the root filesystem
  1209. rootflags= [KNL] Set root filesystem mount option string
  1210. rootfstype= [KNL] Set root filesystem type
  1211. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1212. Useful for devices that are detected asynchronously
  1213. (e.g. USB and MMC devices).
  1214. root_plug.vendor_id=
  1215. [ROOTPLUG] Override the default vendor ID
  1216. root_plug.product_id=
  1217. [ROOTPLUG] Override the default product ID
  1218. root_plug.debug=
  1219. [ROOTPLUG] Enable debugging output
  1220. rw [KNL] Mount root device read-write on boot
  1221. S [KNL] Run init in single mode
  1222. sa1100ir [NET]
  1223. See drivers/net/irda/sa1100_ir.c.
  1224. sbni= [NET] Granch SBNI12 leased line adapter
  1225. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1226. Format: <io>[,<timeout>[,<isapnp>]]
  1227. scsi_debug_*= [SCSI]
  1228. See drivers/scsi/scsi_debug.c.
  1229. scsi_default_dev_flags=
  1230. [SCSI] SCSI default device flags
  1231. Format: <integer>
  1232. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1233. Format: <vendor>:<model>:<flags>
  1234. (flags are integer value)
  1235. scsi_logging= [SCSI]
  1236. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1237. discovered. async scans them in kernel threads,
  1238. allowing boot to proceed. none ignores them, expecting
  1239. user space to do the scan.
  1240. selinux [SELINUX] Disable or enable SELinux at boot time.
  1241. Format: { "0" | "1" }
  1242. See security/selinux/Kconfig help text.
  1243. 0 -- disable.
  1244. 1 -- enable.
  1245. Default value is set via kernel config option.
  1246. If enabled at boot time, /selinux/disable can be used
  1247. later to disable prior to initial policy load.
  1248. selinux_compat_net =
  1249. [SELINUX] Set initial selinux_compat_net flag value.
  1250. Format: { "0" | "1" }
  1251. 0 -- use new secmark-based packet controls
  1252. 1 -- use legacy packet controls
  1253. Default value is 0 (preferred).
  1254. Value can be changed at runtime via
  1255. /selinux/compat_net.
  1256. serialnumber [BUGS=X86-32]
  1257. shapers= [NET]
  1258. Maximal number of shapers.
  1259. sim710= [SCSI,HW]
  1260. See header of drivers/scsi/sim710.c.
  1261. simeth= [IA-64]
  1262. simscsi=
  1263. slram= [HW,MTD]
  1264. slub_debug[=options[,slabs]] [MM, SLUB]
  1265. Enabling slub_debug allows one to determine the
  1266. culprit if slab objects become corrupted. Enabling
  1267. slub_debug can create guard zones around objects and
  1268. may poison objects when not in use. Also tracks the
  1269. last alloc / free. For more information see
  1270. Documentation/vm/slub.txt.
  1271. slub_max_order= [MM, SLUB]
  1272. Determines the maximum allowed order for slabs.
  1273. A high setting may cause OOMs due to memory
  1274. fragmentation. For more information see
  1275. Documentation/vm/slub.txt.
  1276. slub_min_objects= [MM, SLUB]
  1277. The minimum number of objects per slab. SLUB will
  1278. increase the slab order up to slub_max_order to
  1279. generate a sufficiently large slab able to contain
  1280. the number of objects indicated. The higher the number
  1281. of objects the smaller the overhead of tracking slabs
  1282. and the less frequently locks need to be acquired.
  1283. For more information see Documentation/vm/slub.txt.
  1284. slub_min_order= [MM, SLUB]
  1285. Determines the mininum page order for slabs. Must be
  1286. lower than slub_max_order.
  1287. For more information see Documentation/vm/slub.txt.
  1288. slub_nomerge [MM, SLUB]
  1289. Disable merging of slabs with similar size. May be
  1290. necessary if there is some reason to distinguish
  1291. allocs to different slabs. Debug options disable
  1292. merging on their own.
  1293. For more information see Documentation/vm/slub.txt.
  1294. smart2= [HW]
  1295. Format: <io1>[,<io2>[,...,<io8>]]
  1296. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1297. attempt to substitute SMP alternatives once at boot.
  1298. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1299. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1300. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1301. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1302. smsc-ircc2.ircc_irq= [HW] IRQ line
  1303. smsc-ircc2.ircc_dma= [HW] DMA channel
  1304. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1305. 0: Toshiba Satellite 1800 (GP data pin select)
  1306. 1: Fast pin select (default)
  1307. 2: ATC IRMode
  1308. snd-ad1816a= [HW,ALSA]
  1309. snd-ad1848= [HW,ALSA]
  1310. snd-ali5451= [HW,ALSA]
  1311. snd-als100= [HW,ALSA]
  1312. snd-als4000= [HW,ALSA]
  1313. snd-azt2320= [HW,ALSA]
  1314. snd-cmi8330= [HW,ALSA]
  1315. snd-cmipci= [HW,ALSA]
  1316. snd-cs4231= [HW,ALSA]
  1317. snd-cs4232= [HW,ALSA]
  1318. snd-cs4236= [HW,ALSA]
  1319. snd-cs4281= [HW,ALSA]
  1320. snd-cs46xx= [HW,ALSA]
  1321. snd-dt019x= [HW,ALSA]
  1322. snd-dummy= [HW,ALSA]
  1323. snd-emu10k1= [HW,ALSA]
  1324. snd-ens1370= [HW,ALSA]
  1325. snd-ens1371= [HW,ALSA]
  1326. snd-es968= [HW,ALSA]
  1327. snd-es1688= [HW,ALSA]
  1328. snd-es18xx= [HW,ALSA]
  1329. snd-es1938= [HW,ALSA]
  1330. snd-es1968= [HW,ALSA]
  1331. snd-fm801= [HW,ALSA]
  1332. snd-gusclassic= [HW,ALSA]
  1333. snd-gusextreme= [HW,ALSA]
  1334. snd-gusmax= [HW,ALSA]
  1335. snd-hdsp= [HW,ALSA]
  1336. snd-ice1712= [HW,ALSA]
  1337. snd-intel8x0= [HW,ALSA]
  1338. snd-interwave= [HW,ALSA]
  1339. snd-interwave-stb=
  1340. [HW,ALSA]
  1341. snd-korg1212= [HW,ALSA]
  1342. snd-maestro3= [HW,ALSA]
  1343. snd-mpu401= [HW,ALSA]
  1344. snd-mtpav= [HW,ALSA]
  1345. snd-nm256= [HW,ALSA]
  1346. snd-opl3sa2= [HW,ALSA]
  1347. snd-opti92x-ad1848=
  1348. [HW,ALSA]
  1349. snd-opti92x-cs4231=
  1350. [HW,ALSA]
  1351. snd-opti93x= [HW,ALSA]
  1352. snd-pmac= [HW,ALSA]
  1353. snd-rme32= [HW,ALSA]
  1354. snd-rme96= [HW,ALSA]
  1355. snd-rme9652= [HW,ALSA]
  1356. snd-sb8= [HW,ALSA]
  1357. snd-sb16= [HW,ALSA]
  1358. snd-sbawe= [HW,ALSA]
  1359. snd-serial= [HW,ALSA]
  1360. snd-sgalaxy= [HW,ALSA]
  1361. snd-sonicvibes= [HW,ALSA]
  1362. snd-sun-amd7930=
  1363. [HW,ALSA]
  1364. snd-sun-cs4231= [HW,ALSA]
  1365. snd-trident= [HW,ALSA]
  1366. snd-usb-audio= [HW,ALSA,USB]
  1367. snd-via82xx= [HW,ALSA]
  1368. snd-virmidi= [HW,ALSA]
  1369. snd-wavefront= [HW,ALSA]
  1370. snd-ymfpci= [HW,ALSA]
  1371. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1372. See Documentation/sonypi.txt
  1373. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1374. See Documentation/specialix.txt.
  1375. spia_io_base= [HW,MTD]
  1376. spia_fio_base=
  1377. spia_pedr=
  1378. spia_peddr=
  1379. sscape= [HW,OSS]
  1380. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1381. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1382. See Documentation/scsi/st.txt.
  1383. st0x= [HW,SCSI]
  1384. See header of drivers/scsi/seagate.c.
  1385. sti= [PARISC,HW]
  1386. Format: <num>
  1387. Set the STI (builtin display/keyboard on the HP-PARISC
  1388. machines) console (graphic card) which should be used
  1389. as the initial boot-console.
  1390. See also comment in drivers/video/console/sticore.c.
  1391. sti_font= [HW]
  1392. See comment in drivers/video/console/sticore.c.
  1393. stifb= [HW]
  1394. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1395. sunrpc.pool_mode=
  1396. [NFS]
  1397. Control how the NFS server code allocates CPUs to
  1398. service thread pools. Depending on how many NICs
  1399. you have and where their interrupts are bound, this
  1400. option will affect which CPUs will do NFS serving.
  1401. Note: this parameter cannot be changed while the
  1402. NFS server is running.
  1403. auto the server chooses an appropriate mode
  1404. automatically using heuristics
  1405. global a single global pool contains all CPUs
  1406. percpu one pool for each CPU
  1407. pernode one pool for each NUMA node (equivalent
  1408. to global on non-NUMA machines)
  1409. swiotlb= [IA-64] Number of I/O TLB slabs
  1410. switches= [HW,M68k]
  1411. sym53c416= [HW,SCSI]
  1412. See header of drivers/scsi/sym53c416.c.
  1413. sysrq_always_enabled
  1414. [KNL]
  1415. Ignore sysrq setting - this boot parameter will
  1416. neutralize any effect of /proc/sys/kernel/sysrq.
  1417. Useful for debugging.
  1418. t128= [HW,SCSI]
  1419. See header of drivers/scsi/t128.c.
  1420. tdfx= [HW,DRM]
  1421. thash_entries= [KNL,NET]
  1422. Set number of hash buckets for TCP connection
  1423. thermal.act= [HW,ACPI]
  1424. -1: disable all active trip points in all thermal zones
  1425. <degrees C>: override all lowest active trip points
  1426. thermal.crt= [HW,ACPI]
  1427. -1: disable all critical trip points in all thermal zones
  1428. <degrees C>: lower all critical trip points
  1429. thermal.nocrt= [HW,ACPI]
  1430. Set to disable actions on ACPI thermal zone
  1431. critical and hot trip points.
  1432. thermal.off= [HW,ACPI]
  1433. 1: disable ACPI thermal control
  1434. thermal.psv= [HW,ACPI]
  1435. -1: disable all passive trip points
  1436. <degrees C>: override all passive trip points to this value
  1437. thermal.tzp= [HW,ACPI]
  1438. Specify global default ACPI thermal zone polling rate
  1439. <deci-seconds>: poll all this frequency
  1440. 0: no polling (default)
  1441. time Show timing data prefixed to each printk message line
  1442. [deprecated, see 'printk.time']
  1443. tipar.timeout= [HW,PPT]
  1444. Set communications timeout in tenths of a second
  1445. (default 15).
  1446. tipar.delay= [HW,PPT]
  1447. Set inter-bit delay in microseconds (default 10).
  1448. tmc8xx= [HW,SCSI]
  1449. See header of drivers/scsi/seagate.c.
  1450. tmscsim= [HW,SCSI]
  1451. See comment before function dc390_setup() in
  1452. drivers/scsi/tmscsim.c.
  1453. tp720= [HW,PS2]
  1454. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1455. Format:
  1456. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1457. turbografx.map[2|3]= [HW,JOY]
  1458. TurboGraFX parallel port interface
  1459. Format:
  1460. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1461. See also Documentation/input/joystick-parport.txt
  1462. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1463. See header of drivers/scsi/u14-34f.c.
  1464. uart401= [HW,OSS]
  1465. Format: <io>,<irq>
  1466. uart6850= [HW,OSS]
  1467. Format: <io>,<irq>
  1468. uhci-hcd.ignore_oc=
  1469. [USB] Ignore overcurrent events (default N).
  1470. Some badly-designed motherboards generate lots of
  1471. bogus events, for ports that aren't wired to
  1472. anything. Set this parameter to avoid log spamming.
  1473. Note that genuine overcurrent events won't be
  1474. reported either.
  1475. usbcore.autosuspend=
  1476. [USB] The autosuspend time delay (in seconds) used
  1477. for newly-detected USB devices (default 2). This
  1478. is the time required before an idle device will be
  1479. autosuspended. Devices for which the delay is set
  1480. to a negative value won't be autosuspended at all.
  1481. usbhid.mousepoll=
  1482. [USBHID] The interval which mice are to be polled at.
  1483. vdso= [X86-32,SH,x86-64]
  1484. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1485. vdso=1: enable VDSO (default)
  1486. vdso=0: disable VDSO mapping
  1487. vector= [IA-64,SMP]
  1488. vector=percpu: enable percpu vector domain
  1489. video= [FB] Frame buffer configuration
  1490. See Documentation/fb/modedb.txt.
  1491. vga= [BOOT,X86-32] Select a particular video mode
  1492. See Documentation/i386/boot.txt and
  1493. Documentation/svga.txt.
  1494. Use vga=ask for menu.
  1495. This is actually a boot loader parameter; the value is
  1496. passed to the kernel using a special protocol.
  1497. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1498. size of <nn>. This can be used to increase the
  1499. minimum size (128MB on x86). It can also be used to
  1500. decrease the size and leave more room for directly
  1501. mapped kernel RAM.
  1502. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1503. Format: <command>
  1504. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1505. Format: <command>
  1506. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1507. Format: <command>
  1508. waveartist= [HW,OSS]
  1509. Format: <io>,<irq>,<dma>,<dma2>
  1510. wd33c93= [HW,SCSI]
  1511. See header of drivers/scsi/wd33c93.c.
  1512. wd7000= [HW,SCSI]
  1513. See header of drivers/scsi/wd7000.c.
  1514. wdt= [WDT] Watchdog
  1515. See Documentation/watchdog/wdt.txt.
  1516. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1517. xd_geo= See header of drivers/block/xd.c.
  1518. xirc2ps_cs= [NET,PCMCIA]
  1519. Format:
  1520. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1521. norandmaps Don't use address space randomization
  1522. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1523. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1524. This is useful to get more information why
  1525. you got a "dwarf2 unwinder stuck"
  1526. ______________________________________________________________________
  1527. TODO:
  1528. Add documentation for ALSA options.
  1529. Add more DRM drivers.