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1 | Kernel Parameters |
2 | ~~~~~~~~~~~~~~~~~ |
3 | |
4 | The following is a consolidated list of the kernel parameters as implemented |
5 | (mostly) by the __setup() macro and sorted into English Dictionary order |
6 | (defined as ignoring all punctuation and sorting digits before letters in a |
7 | case insensitive manner), and with descriptions where known. |
8 | |
9 | Module parameters for loadable modules are specified only as the |
10 | parameter name with optional '=' and value as appropriate, such as: |
11 | |
12 | modprobe usbcore blinkenlights=1 |
13 | |
14 | Module parameters for modules that are built into the kernel image |
15 | are specified on the kernel command line with the module name plus |
16 | '.' plus parameter name, with '=' and value if appropriate, such as: |
17 | |
18 | usbcore.blinkenlights=1 |
19 | |
20 | Hyphens (dashes) and underscores are equivalent in parameter names, so |
21 | log_buf_len=1M print-fatal-signals=1 |
22 | can also be entered as |
23 | log-buf-len=1M print_fatal_signals=1 |
24 | |
25 | |
26 | This document may not be entirely up to date and comprehensive. The command |
27 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable |
28 | module. Loadable modules, after being loaded into the running kernel, also |
29 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these |
30 | parameters may be changed at runtime by the command |
31 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". |
32 | |
33 | The parameters listed below are only valid if certain kernel build options were |
34 | enabled and if respective hardware is present. The text in square brackets at |
35 | the beginning of each description states the restrictions within which a |
36 | parameter is applicable: |
37 | |
38 | ACPI ACPI support is enabled. |
39 | AGP AGP (Accelerated Graphics Port) is enabled. |
40 | ALSA ALSA sound support is enabled. |
41 | APIC APIC support is enabled. |
42 | APM Advanced Power Management support is enabled. |
43 | AVR32 AVR32 architecture is enabled. |
44 | AX25 Appropriate AX.25 support is enabled. |
45 | BLACKFIN Blackfin architecture is enabled. |
46 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled |
47 | EFI EFI Partitioning (GPT) is enabled |
48 | EIDE EIDE/ATAPI support is enabled. |
49 | DRM Direct Rendering Management support is enabled. |
50 | DYNAMIC_DEBUG Build in debug messages and enable them at runtime |
51 | FB The frame buffer device is enabled. |
52 | GCOV GCOV profiling is enabled. |
53 | HW Appropriate hardware is enabled. |
54 | IA-64 IA-64 architecture is enabled. |
55 | IMA Integrity measurement architecture is enabled. |
56 | IOSCHED More than one I/O scheduler is enabled. |
57 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. |
58 | IPV6 IPv6 support is enabled. |
59 | ISAPNP ISA PnP code is enabled. |
60 | ISDN Appropriate ISDN support is enabled. |
61 | JOY Appropriate joystick support is enabled. |
62 | KGDB Kernel debugger support is enabled. |
63 | KVM Kernel Virtual Machine support is enabled. |
64 | LIBATA Libata driver is enabled |
65 | LP Printer support is enabled. |
66 | LOOP Loopback device support is enabled. |
67 | M68k M68k architecture is enabled. |
68 | These options have more detailed description inside of |
69 | Documentation/m68k/kernel-options.txt. |
70 | MCA MCA bus support is enabled. |
71 | MDA MDA console support is enabled. |
72 | MOUSE Appropriate mouse support is enabled. |
73 | MSI Message Signaled Interrupts (PCI). |
74 | MTD MTD (Memory Technology Device) support is enabled. |
75 | NET Appropriate network support is enabled. |
76 | NUMA NUMA support is enabled. |
77 | NFS Appropriate NFS support is enabled. |
78 | OSS OSS sound support is enabled. |
79 | PV_OPS A paravirtualized kernel is enabled. |
80 | PARIDE The ParIDE (parallel port IDE) subsystem is enabled. |
81 | PARISC The PA-RISC architecture is enabled. |
82 | PCI PCI bus support is enabled. |
83 | PCIE PCI Express support is enabled. |
84 | PCMCIA The PCMCIA subsystem is enabled. |
85 | PNP Plug & Play support is enabled. |
86 | PPC PowerPC architecture is enabled. |
87 | PPT Parallel port support is enabled. |
88 | PS2 Appropriate PS/2 support is enabled. |
89 | RAM RAM disk support is enabled. |
90 | S390 S390 architecture is enabled. |
91 | SCSI Appropriate SCSI support is enabled. |
92 | A lot of drivers have their options described inside |
93 | the Documentation/scsi/ sub-directory. |
94 | SECURITY Different security models are enabled. |
95 | SELINUX SELinux support is enabled. |
96 | APPARMOR AppArmor support is enabled. |
97 | SERIAL Serial support is enabled. |
98 | SH SuperH architecture is enabled. |
99 | SMP The kernel is an SMP kernel. |
100 | SPARC Sparc architecture is enabled. |
101 | SWSUSP Software suspend (hibernation) is enabled. |
102 | SUSPEND System suspend states are enabled. |
103 | FTRACE Function tracing enabled. |
104 | TPM TPM drivers are enabled. |
105 | TS Appropriate touchscreen support is enabled. |
106 | UMS USB Mass Storage support is enabled. |
107 | USB USB support is enabled. |
108 | USBHID USB Human Interface Device support is enabled. |
109 | V4L Video For Linux support is enabled. |
110 | VGA The VGA console has been enabled. |
111 | VT Virtual terminal support is enabled. |
112 | WDT Watchdog support is enabled. |
113 | XT IBM PC/XT MFM hard disk support is enabled. |
114 | X86-32 X86-32, aka i386 architecture is enabled. |
115 | X86-64 X86-64 architecture is enabled. |
116 | More X86-64 boot options can be found in |
117 | Documentation/x86/x86_64/boot-options.txt . |
118 | X86 Either 32bit or 64bit x86 (same as X86-32+X86-64) |
119 | XEN Xen support is enabled |
120 | |
121 | In addition, the following text indicates that the option: |
122 | |
123 | BUGS= Relates to possible processor bugs on the said processor. |
124 | KNL Is a kernel start-up parameter. |
125 | BOOT Is a boot loader parameter. |
126 | |
127 | Parameters denoted with BOOT are actually interpreted by the boot |
128 | loader, and have no meaning to the kernel directly. |
129 | Do not modify the syntax of boot loader parameters without extreme |
130 | need or coordination with <Documentation/x86/boot.txt>. |
131 | |
132 | There are also arch-specific kernel-parameters not documented here. |
133 | See for example <Documentation/x86/x86_64/boot-options.txt>. |
134 | |
135 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that |
136 | a trailing = on the name of any parameter states that that parameter will |
137 | be entered as an environment variable, whereas its absence indicates that |
138 | it will appear as a kernel argument readable via /proc/cmdline by programs |
139 | running once the system is up. |
140 | |
141 | The number of kernel parameters is not limited, but the length of the |
142 | complete command line (parameters including spaces etc.) is limited to |
143 | a fixed number of characters. This limit depends on the architecture |
144 | and is between 256 and 4096 characters. It is defined in the file |
145 | ./include/asm/setup.h as COMMAND_LINE_SIZE. |
146 | |
147 | |
148 | acpi= [HW,ACPI,X86] |
149 | Advanced Configuration and Power Interface |
150 | Format: { force | off | strict | noirq | rsdt } |
151 | force -- enable ACPI if default was off |
152 | off -- disable ACPI if default was on |
153 | noirq -- do not use ACPI for IRQ routing |
154 | strict -- Be less tolerant of platforms that are not |
155 | strictly ACPI specification compliant. |
156 | rsdt -- prefer RSDT over (default) XSDT |
157 | copy_dsdt -- copy DSDT to memory |
158 | |
159 | See also Documentation/power/pm.txt, pci=noacpi |
160 | |
161 | acpi_apic_instance= [ACPI, IOAPIC] |
162 | Format: <int> |
163 | 2: use 2nd APIC table, if available |
164 | 1,0: use 1st APIC table |
165 | default: 0 |
166 | |
167 | acpi_backlight= [HW,ACPI] |
168 | acpi_backlight=vendor |
169 | acpi_backlight=video |
170 | If set to vendor, prefer vendor specific driver |
171 | (e.g. thinkpad_acpi, sony_acpi, etc.) instead |
172 | of the ACPI video.ko driver. |
173 | |
174 | acpi.debug_layer= [HW,ACPI,ACPI_DEBUG] |
175 | acpi.debug_level= [HW,ACPI,ACPI_DEBUG] |
176 | Format: <int> |
177 | CONFIG_ACPI_DEBUG must be enabled to produce any ACPI |
178 | debug output. Bits in debug_layer correspond to a |
179 | _COMPONENT in an ACPI source file, e.g., |
180 | #define _COMPONENT ACPI_PCI_COMPONENT |
181 | Bits in debug_level correspond to a level in |
182 | ACPI_DEBUG_PRINT statements, e.g., |
183 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, ... |
184 | The debug_level mask defaults to "info". See |
185 | Documentation/acpi/debug.txt for more information about |
186 | debug layers and levels. |
187 | |
188 | Enable processor driver info messages: |
189 | acpi.debug_layer=0x20000000 |
190 | Enable PCI/PCI interrupt routing info messages: |
191 | acpi.debug_layer=0x400000 |
192 | Enable AML "Debug" output, i.e., stores to the Debug |
193 | object while interpreting AML: |
194 | acpi.debug_layer=0xffffffff acpi.debug_level=0x2 |
195 | Enable all messages related to ACPI hardware: |
196 | acpi.debug_layer=0x2 acpi.debug_level=0xffffffff |
197 | |
198 | Some values produce so much output that the system is |
199 | unusable. The "log_buf_len" parameter may be useful |
200 | if you need to capture more output. |
201 | |
202 | acpi_display_output= [HW,ACPI] |
203 | acpi_display_output=vendor |
204 | acpi_display_output=video |
205 | See above. |
206 | |
207 | acpi_irq_balance [HW,ACPI] |
208 | ACPI will balance active IRQs |
209 | default in APIC mode |
210 | |
211 | acpi_irq_nobalance [HW,ACPI] |
212 | ACPI will not move active IRQs (default) |
213 | default in PIC mode |
214 | |
215 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA |
216 | Format: <irq>,<irq>... |
217 | |
218 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for |
219 | use by PCI |
220 | Format: <irq>,<irq>... |
221 | |
222 | acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT |
223 | |
224 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS |
225 | Format: To spoof as Windows 98: ="Microsoft Windows" |
226 | |
227 | acpi_osi= [HW,ACPI] Modify list of supported OS interface strings |
228 | acpi_osi="string1" # add string1 -- only one string |
229 | acpi_osi="!string2" # remove built-in string2 |
230 | acpi_osi= # disable all strings |
231 | |
232 | acpi_pm_good [X86] |
233 | Override the pmtimer bug detection: force the kernel |
234 | to assume that this machine's pmtimer latches its value |
235 | and always returns good values. |
236 | |
237 | acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode |
238 | Format: { level | edge | high | low } |
239 | |
240 | acpi_serialize [HW,ACPI] force serialization of AML methods |
241 | |
242 | acpi_skip_timer_override [HW,ACPI] |
243 | Recognize and ignore IRQ0/pin2 Interrupt Override. |
244 | For broken nForce2 BIOS resulting in XT-PIC timer. |
245 | |
246 | acpi_sleep= [HW,ACPI] Sleep options |
247 | Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, |
248 | old_ordering, s4_nonvs, sci_force_enable } |
249 | See Documentation/power/video.txt for information on |
250 | s3_bios and s3_mode. |
251 | s3_beep is for debugging; it makes the PC's speaker beep |
252 | as soon as the kernel's real-mode entry point is called. |
253 | s4_nohwsig prevents ACPI hardware signature from being |
254 | used during resume from hibernation. |
255 | old_ordering causes the ACPI 1.0 ordering of the _PTS |
256 | control method, with respect to putting devices into |
257 | low power states, to be enforced (the ACPI 2.0 ordering |
258 | of _PTS is used by default). |
259 | nonvs prevents the kernel from saving/restoring the |
260 | ACPI NVS memory during suspend/hibernation and resume. |
261 | sci_force_enable causes the kernel to set SCI_EN directly |
262 | on resume from S1/S3 (which is against the ACPI spec, |
263 | but some broken systems don't work without it). |
264 | |
265 | acpi_use_timer_override [HW,ACPI] |
266 | Use timer override. For some broken Nvidia NF5 boards |
267 | that require a timer override, but don't have HPET |
268 | |
269 | acpi_enforce_resources= [ACPI] |
270 | { strict | lax | no } |
271 | Check for resource conflicts between native drivers |
272 | and ACPI OperationRegions (SystemIO and SystemMemory |
273 | only). IO ports and memory declared in ACPI might be |
274 | used by the ACPI subsystem in arbitrary AML code and |
275 | can interfere with legacy drivers. |
276 | strict (default): access to resources claimed by ACPI |
277 | is denied; legacy drivers trying to access reserved |
278 | resources will fail to bind to device using them. |
279 | lax: access to resources claimed by ACPI is allowed; |
280 | legacy drivers trying to access reserved resources |
281 | will bind successfully but a warning message is logged. |
282 | no: ACPI OperationRegions are not marked as reserved, |
283 | no further checks are performed. |
284 | |
285 | add_efi_memmap [EFI; X86] Include EFI memory map in |
286 | kernel's map of available physical RAM. |
287 | |
288 | agp= [AGP] |
289 | { off | try_unsupported } |
290 | off: disable AGP support |
291 | try_unsupported: try to drive unsupported chipsets |
292 | (may crash computer or cause data corruption) |
293 | |
294 | ALSA [HW,ALSA] |
295 | See Documentation/sound/alsa/alsa-parameters.txt |
296 | |
297 | alignment= [KNL,ARM] |
298 | Allow the default userspace alignment fault handler |
299 | behaviour to be specified. Bit 0 enables warnings, |
300 | bit 1 enables fixups, and bit 2 sends a segfault. |
301 | |
302 | amd_iommu= [HW,X86-84] |
303 | Pass parameters to the AMD IOMMU driver in the system. |
304 | Possible values are: |
305 | fullflush - enable flushing of IO/TLB entries when |
306 | they are unmapped. Otherwise they are |
307 | flushed before they will be reused, which |
308 | is a lot of faster |
309 | off - do not initialize any AMD IOMMU found in |
310 | the system |
311 | |
312 | amijoy.map= [HW,JOY] Amiga joystick support |
313 | Map of devices attached to JOY0DAT and JOY1DAT |
314 | Format: <a>,<b> |
315 | See also Documentation/kernel/input/joystick.txt |
316 | |
317 | analog.map= [HW,JOY] Analog joystick and gamepad support |
318 | Specifies type or capabilities of an analog joystick |
319 | connected to one of 16 gameports |
320 | Format: <type1>,<type2>,..<type16> |
321 | |
322 | apc= [HW,SPARC] |
323 | Power management functions (SPARCstation-4/5 + deriv.) |
324 | Format: noidle |
325 | Disable APC CPU standby support. SPARCstation-Fox does |
326 | not play well with APC CPU idle - disable it if you have |
327 | APC and your system crashes randomly. |
328 | |
329 | apic= [APIC,X86-32] Advanced Programmable Interrupt Controller |
330 | Change the output verbosity whilst booting |
331 | Format: { quiet (default) | verbose | debug } |
332 | Change the amount of debugging information output |
333 | when initialising the APIC and IO-APIC components. |
334 | |
335 | autoconf= [IPV6] |
336 | See Documentation/networking/ipv6.txt. |
337 | |
338 | show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller |
339 | Limit apic dumping. The parameter defines the maximal |
340 | number of local apics being dumped. Also it is possible |
341 | to set it to "all" by meaning -- no limit here. |
342 | Format: { 1 (default) | 2 | ... | all }. |
343 | The parameter valid if only apic=debug or |
344 | apic=verbose is specified. |
345 | Example: apic=debug show_lapic=all |
346 | |
347 | apm= [APM] Advanced Power Management |
348 | See header of arch/x86/kernel/apm_32.c. |
349 | |
350 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards |
351 | Format: <io>,<irq>,<nodeID> |
352 | |
353 | ataflop= [HW,M68k] |
354 | |
355 | atarimouse= [HW,MOUSE] Atari Mouse |
356 | |
357 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, |
358 | EzKey and similar keyboards |
359 | |
360 | atkbd.reset= [HW] Reset keyboard during initialization |
361 | |
362 | atkbd.set= [HW] Select keyboard code set |
363 | Format: <int> (2 = AT (default), 3 = PS/2) |
364 | |
365 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar |
366 | keyboards |
367 | |
368 | atkbd.softraw= [HW] Choose between synthetic and real raw mode |
369 | Format: <bool> (0 = real, 1 = synthetic (default)) |
370 | |
371 | atkbd.softrepeat= [HW] |
372 | Use software keyboard repeat |
373 | |
374 | autotest [IA64] |
375 | |
376 | baycom_epp= [HW,AX25] |
377 | Format: <io>,<mode> |
378 | |
379 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem |
380 | Format: <io>,<mode> |
381 | See header of drivers/net/hamradio/baycom_par.c. |
382 | |
383 | baycom_ser_fdx= [HW,AX25] |
384 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) |
385 | Format: <io>,<irq>,<mode>[,<baud>] |
386 | See header of drivers/net/hamradio/baycom_ser_fdx.c. |
387 | |
388 | baycom_ser_hdx= [HW,AX25] |
389 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) |
390 | Format: <io>,<irq>,<mode> |
391 | See header of drivers/net/hamradio/baycom_ser_hdx.c. |
392 | |
393 | boot_delay= Milliseconds to delay each printk during boot. |
394 | Values larger than 10 seconds (10000) are changed to |
395 | no delay (0). |
396 | Format: integer |
397 | |
398 | bootmem_debug [KNL] Enable bootmem allocator debug messages. |
399 | |
400 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) |
401 | bttv.radio= Most important insmod options are available as |
402 | kernel args too. |
403 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options |
404 | bttv.tuner= and Documentation/video4linux/bttv/CARDLIST |
405 | |
406 | c101= [NET] Moxa C101 synchronous serial card |
407 | |
408 | cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection. |
409 | Sometimes CPU hardware bugs make them report the cache |
410 | size incorrectly. The kernel will attempt work arounds |
411 | to fix known problems, but for some CPUs it is not |
412 | possible to determine what the correct size should be. |
413 | This option provides an override for these situations. |
414 | |
415 | capability.disable= |
416 | [SECURITY] Disable capabilities. This would normally |
417 | be used only if an alternative security model is to be |
418 | configured. Potentially dangerous and should only be |
419 | used if you are entirely sure of the consequences. |
420 | |
421 | ccw_timeout_log [S390] |
422 | See Documentation/s390/CommonIO for details. |
423 | |
424 | cgroup_disable= [KNL] Disable a particular controller |
425 | Format: {name of the controller(s) to disable} |
426 | {Currently supported controllers - "memory"} |
427 | |
428 | checkreqprot [SELINUX] Set initial checkreqprot flag value. |
429 | Format: { "0" | "1" } |
430 | See security/selinux/Kconfig help text. |
431 | 0 -- check protection applied by kernel (includes |
432 | any implied execute protection). |
433 | 1 -- check protection requested by application. |
434 | Default value is set via a kernel config option. |
435 | Value can be changed at runtime via |
436 | /selinux/checkreqprot. |
437 | |
438 | cio_ignore= [S390] |
439 | See Documentation/s390/CommonIO for details. |
440 | |
441 | clock= [BUGS=X86-32, HW] gettimeofday clocksource override. |
442 | [Deprecated] |
443 | Forces specified clocksource (if available) to be used |
444 | when calculating gettimeofday(). If specified |
445 | clocksource is not available, it defaults to PIT. |
446 | Format: { pit | tsc | cyclone | pmtmr } |
447 | |
448 | clocksource= Override the default clocksource |
449 | Format: <string> |
450 | Override the default clocksource and use the clocksource |
451 | with the name specified. |
452 | Some clocksource names to choose from, depending on |
453 | the platform: |
454 | [all] jiffies (this is the base, fallback clocksource) |
455 | [ACPI] acpi_pm |
456 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, |
457 | pxa_timer,timer3,32k_counter,timer0_1 |
458 | [AVR32] avr32 |
459 | [X86-32] pit,hpet,tsc; |
460 | scx200_hrt on Geode; cyclone on IBM x440 |
461 | [MIPS] MIPS |
462 | [PARISC] cr16 |
463 | [S390] tod |
464 | [SH] SuperH |
465 | [SPARC64] tick |
466 | [X86-64] hpet,tsc |
467 | |
468 | clearcpuid=BITNUM [X86] |
469 | Disable CPUID feature X for the kernel. See |
470 | arch/x86/include/asm/cpufeature.h for the valid bit |
471 | numbers. Note the Linux specific bits are not necessarily |
472 | stable over kernel options, but the vendor specific |
473 | ones should be. |
474 | Also note that user programs calling CPUID directly |
475 | or using the feature without checking anything |
476 | will still see it. This just prevents it from |
477 | being used by the kernel or shown in /proc/cpuinfo. |
478 | Also note the kernel might malfunction if you disable |
479 | some critical bits. |
480 | |
481 | cmo_free_hint= [PPC] Format: { yes | no } |
482 | Specify whether pages are marked as being inactive |
483 | when they are freed. This is used in CMO environments |
484 | to determine OS memory pressure for page stealing by |
485 | a hypervisor. |
486 | Default: yes |
487 | |
488 | code_bytes [X86] How many bytes of object code to print |
489 | in an oops report. |
490 | Range: 0 - 8192 |
491 | Default: 64 |
492 | |
493 | com20020= [HW,NET] ARCnet - COM20020 chipset |
494 | Format: |
495 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] |
496 | |
497 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) |
498 | Format: <io>[,<irq>] |
499 | |
500 | com90xx= [HW,NET] |
501 | ARCnet - COM90xx chipset (memory-mapped buffers) |
502 | Format: <io>[,<irq>[,<memstart>]] |
503 | |
504 | condev= [HW,S390] console device |
505 | conmode= |
506 | |
507 | console= [KNL] Output console device and options. |
508 | |
509 | tty<n> Use the virtual console device <n>. |
510 | |
511 | ttyS<n>[,options] |
512 | ttyUSB0[,options] |
513 | Use the specified serial port. The options are of |
514 | the form "bbbbpnf", where "bbbb" is the baud rate, |
515 | "p" is parity ("n", "o", or "e"), "n" is number of |
516 | bits, and "f" is flow control ("r" for RTS or |
517 | omit it). Default is "9600n8". |
518 | |
519 | See Documentation/serial-console.txt for more |
520 | information. See |
521 | Documentation/networking/netconsole.txt for an |
522 | alternative. |
523 | |
524 | uart[8250],io,<addr>[,options] |
525 | uart[8250],mmio,<addr>[,options] |
526 | Start an early, polled-mode console on the 8250/16550 |
527 | UART at the specified I/O port or MMIO address, |
528 | switching to the matching ttyS device later. The |
529 | options are the same as for ttyS, above. |
530 | |
531 | If the device connected to the port is not a TTY but a braille |
532 | device, prepend "brl," before the device type, for instance |
533 | console=brl,ttyS0 |
534 | For now, only VisioBraille is supported. |
535 | |
536 | consoleblank= [KNL] The console blank (screen saver) timeout in |
537 | seconds. Defaults to 10*60 = 10mins. A value of 0 |
538 | disables the blank timer. |
539 | |
540 | coredump_filter= |
541 | [KNL] Change the default value for |
542 | /proc/<pid>/coredump_filter. |
543 | See also Documentation/filesystems/proc.txt. |
544 | |
545 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver |
546 | Format: |
547 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] |
548 | |
549 | crashkernel=nn[KMG]@ss[KMG] |
550 | [KNL] Reserve a chunk of physical memory to |
551 | hold a kernel to switch to with kexec on panic. |
552 | |
553 | crashkernel=range1:size1[,range2:size2,...][@offset] |
554 | [KNL] Same as above, but depends on the memory |
555 | in the running system. The syntax of range is |
556 | start-[end] where start and end are both |
557 | a memory unit (amount[KMG]). See also |
558 | Documentation/kdump/kdump.txt for a example. |
559 | |
560 | cs89x0_dma= [HW,NET] |
561 | Format: <dma> |
562 | |
563 | cs89x0_media= [HW,NET] |
564 | Format: { rj45 | aui | bnc } |
565 | |
566 | dasd= [HW,NET] |
567 | See header of drivers/s390/block/dasd_devmap.c. |
568 | |
569 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port |
570 | (one device per port) |
571 | Format: <port#>,<type> |
572 | See also Documentation/input/joystick-parport.txt |
573 | |
574 | ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot |
575 | time. See Documentation/dynamic-debug-howto.txt for |
576 | details. |
577 | |
578 | debug [KNL] Enable kernel debugging (events log level). |
579 | |
580 | debug_locks_verbose= |
581 | [KNL] verbose self-tests |
582 | Format=<0|1> |
583 | Print debugging info while doing the locking API |
584 | self-tests. |
585 | We default to 0 (no extra messages), setting it to |
586 | 1 will print _a lot_ more information - normally |
587 | only useful to kernel developers. |
588 | |
589 | debug_objects [KNL] Enable object debugging |
590 | |
591 | no_debug_objects |
592 | [KNL] Disable object debugging |
593 | |
594 | debugpat [X86] Enable PAT debugging |
595 | |
596 | decnet.addr= [HW,NET] |
597 | Format: <area>[,<node>] |
598 | See also Documentation/networking/decnet.txt. |
599 | |
600 | default_hugepagesz= |
601 | [same as hugepagesz=] The size of the default |
602 | HugeTLB page size. This is the size represented by |
603 | the legacy /proc/ hugepages APIs, used for SHM, and |
604 | default size when mounting hugetlbfs filesystems. |
605 | Defaults to the default architecture's huge page size |
606 | if not specified. |
607 | |
608 | dhash_entries= [KNL] |
609 | Set number of hash buckets for dentry cache. |
610 | |
611 | digi= [HW,SERIAL] |
612 | IO parameters + enable/disable command. |
613 | |
614 | digiepca= [HW,SERIAL] |
615 | See drivers/char/README.epca and |
616 | Documentation/serial/digiepca.txt. |
617 | |
618 | disable= [IPV6] |
619 | See Documentation/networking/ipv6.txt. |
620 | |
621 | disable_ipv6= [IPV6] |
622 | See Documentation/networking/ipv6.txt. |
623 | |
624 | disable_mtrr_cleanup [X86] |
625 | The kernel tries to adjust MTRR layout from continuous |
626 | to discrete, to make X server driver able to add WB |
627 | entry later. This parameter disables that. |
628 | |
629 | disable_mtrr_trim [X86, Intel and AMD only] |
630 | By default the kernel will trim any uncacheable |
631 | memory out of your available memory pool based on |
632 | MTRR settings. This parameter disables that behavior, |
633 | possibly causing your machine to run very slowly. |
634 | |
635 | disable_timer_pin_1 [X86] |
636 | Disable PIN 1 of APIC timer |
637 | Can be useful to work around chipset bugs. |
638 | |
639 | dma_debug=off If the kernel is compiled with DMA_API_DEBUG support, |
640 | this option disables the debugging code at boot. |
641 | |
642 | dma_debug_entries=<number> |
643 | This option allows to tune the number of preallocated |
644 | entries for DMA-API debugging code. One entry is |
645 | required per DMA-API allocation. Use this if the |
646 | DMA-API debugging code disables itself because the |
647 | architectural default is too low. |
648 | |
649 | dma_debug_driver=<driver_name> |
650 | With this option the DMA-API debugging driver |
651 | filter feature can be enabled at boot time. Just |
652 | pass the driver to filter for as the parameter. |
653 | The filter can be disabled or changed to another |
654 | driver later using sysfs. |
655 | |
656 | dscc4.setup= [NET] |
657 | |
658 | dynamic_printk Enables pr_debug()/dev_dbg() calls if |
659 | CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. |
660 | These can also be switched on/off via |
661 | <debugfs>/dynamic_printk/modules |
662 | |
663 | earlycon= [KNL] Output early console device and options. |
664 | uart[8250],io,<addr>[,options] |
665 | uart[8250],mmio,<addr>[,options] |
666 | uart[8250],mmio32,<addr>[,options] |
667 | Start an early, polled-mode console on the 8250/16550 |
668 | UART at the specified I/O port or MMIO address. |
669 | MMIO inter-register address stride is either 8bit (mmio) |
670 | or 32bit (mmio32). |
671 | The options are the same as for ttyS, above. |
672 | |
673 | earlyprintk= [X86,SH,BLACKFIN] |
674 | earlyprintk=vga |
675 | earlyprintk=serial[,ttySn[,baudrate]] |
676 | earlyprintk=ttySn[,baudrate] |
677 | earlyprintk=dbgp[debugController#] |
678 | |
679 | Append ",keep" to not disable it when the real console |
680 | takes over. |
681 | |
682 | Only vga or serial or usb debug port at a time. |
683 | |
684 | Currently only ttyS0 and ttyS1 are supported. |
685 | |
686 | Interaction with the standard serial driver is not |
687 | very good. |
688 | |
689 | The VGA output is eventually overwritten by the real |
690 | console. |
691 | |
692 | ekgdboc= [X86,KGDB] Allow early kernel console debugging |
693 | ekgdboc=kbd |
694 | |
695 | This is desgined to be used in conjunction with |
696 | the boot argument: earlyprintk=vga |
697 | |
698 | edd= [EDD] |
699 | Format: {"off" | "on" | "skip[mbr]"} |
700 | |
701 | eisa_irq_edge= [PARISC,HW] |
702 | See header of drivers/parisc/eisa.c. |
703 | |
704 | elanfreq= [X86-32] |
705 | See comment before function elanfreq_setup() in |
706 | arch/x86/kernel/cpu/cpufreq/elanfreq.c. |
707 | |
708 | elevator= [IOSCHED] |
709 | Format: {"cfq" | "deadline" | "noop"} |
710 | See Documentation/block/as-iosched.txt and |
711 | Documentation/block/deadline-iosched.txt for details. |
712 | |
713 | elfcorehdr= [IA64,PPC,SH,X86] |
714 | Specifies physical address of start of kernel core |
715 | image elf header. Generally kexec loader will |
716 | pass this option to capture kernel. |
717 | See Documentation/kdump/kdump.txt for details. |
718 | |
719 | enable_mtrr_cleanup [X86] |
720 | The kernel tries to adjust MTRR layout from continuous |
721 | to discrete, to make X server driver able to add WB |
722 | entry later. This parameter enables that. |
723 | |
724 | enable_timer_pin_1 [X86] |
725 | Enable PIN 1 of APIC timer |
726 | Can be useful to work around chipset bugs |
727 | (in particular on some ATI chipsets). |
728 | The kernel tries to set a reasonable default. |
729 | |
730 | enforcing [SELINUX] Set initial enforcing status. |
731 | Format: {"0" | "1"} |
732 | See security/selinux/Kconfig help text. |
733 | 0 -- permissive (log only, no denials). |
734 | 1 -- enforcing (deny and log). |
735 | Default value is 0. |
736 | Value can be changed at runtime via /selinux/enforce. |
737 | |
738 | erst_disable [ACPI] |
739 | Disable Error Record Serialization Table (ERST) |
740 | support. |
741 | |
742 | ether= [HW,NET] Ethernet cards parameters |
743 | This option is obsoleted by the "netdev=" option, which |
744 | has equivalent usage. See its documentation for details. |
745 | |
746 | failslab= |
747 | fail_page_alloc= |
748 | fail_make_request=[KNL] |
749 | General fault injection mechanism. |
750 | Format: <interval>,<probability>,<space>,<times> |
751 | See also /Documentation/fault-injection/. |
752 | |
753 | floppy= [HW] |
754 | See Documentation/blockdev/floppy.txt. |
755 | |
756 | force_pal_cache_flush |
757 | [IA-64] Avoid check_sal_cache_flush which may hang on |
758 | buggy SAL_CACHE_FLUSH implementations. Using this |
759 | parameter will force ia64_sal_cache_flush to call |
760 | ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. |
761 | |
762 | ftrace=[tracer] |
763 | [FTRACE] will set and start the specified tracer |
764 | as early as possible in order to facilitate early |
765 | boot debugging. |
766 | |
767 | ftrace_dump_on_oops[=orig_cpu] |
768 | [FTRACE] will dump the trace buffers on oops. |
769 | If no parameter is passed, ftrace will dump |
770 | buffers of all CPUs, but if you pass orig_cpu, it will |
771 | dump only the buffer of the CPU that triggered the |
772 | oops. |
773 | |
774 | ftrace_filter=[function-list] |
775 | [FTRACE] Limit the functions traced by the function |
776 | tracer at boot up. function-list is a comma separated |
777 | list of functions. This list can be changed at run |
778 | time by the set_ftrace_filter file in the debugfs |
779 | tracing directory. |
780 | |
781 | ftrace_notrace=[function-list] |
782 | [FTRACE] Do not trace the functions specified in |
783 | function-list. This list can be changed at run time |
784 | by the set_ftrace_notrace file in the debugfs |
785 | tracing directory. |
786 | |
787 | ftrace_graph_filter=[function-list] |
788 | [FTRACE] Limit the top level callers functions traced |
789 | by the function graph tracer at boot up. |
790 | function-list is a comma separated list of functions |
791 | that can be changed at run time by the |
792 | set_graph_function file in the debugfs tracing directory. |
793 | |
794 | gamecon.map[2|3]= |
795 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad |
796 | support via parallel port (up to 5 devices per port) |
797 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> |
798 | See also Documentation/input/joystick-parport.txt |
799 | |
800 | gamma= [HW,DRM] |
801 | |
802 | gart_fix_e820= [X86_64] disable the fix e820 for K8 GART |
803 | Format: off | on |
804 | default: on |
805 | |
806 | gcov_persist= [GCOV] When non-zero (default), profiling data for |
807 | kernel modules is saved and remains accessible via |
808 | debugfs, even when the module is unloaded/reloaded. |
809 | When zero, profiling data is discarded and associated |
810 | debugfs files are removed at module unload time. |
811 | |
812 | gpt [EFI] Forces disk with valid GPT signature but |
813 | invalid Protective MBR to be treated as GPT. |
814 | |
815 | hashdist= [KNL,NUMA] Large hashes allocated during boot |
816 | are distributed across NUMA nodes. Defaults on |
817 | for 64bit NUMA, off otherwise. |
818 | Format: 0 | 1 (for off | on) |
819 | |
820 | hcl= [IA-64] SGI's Hardware Graph compatibility layer |
821 | |
822 | hd= [EIDE] (E)IDE hard drive subsystem geometry |
823 | Format: <cyl>,<head>,<sect> |
824 | |
825 | hest_disable [ACPI] |
826 | Disable Hardware Error Source Table (HEST) support; |
827 | corresponding firmware-first mode error processing |
828 | logic will be disabled. |
829 | |
830 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact |
831 | size of <nn>. This works even on boxes that have no |
832 | highmem otherwise. This also works to reduce highmem |
833 | size on bigger boxes. |
834 | |
835 | highres= [KNL] Enable/disable high resolution timer mode. |
836 | Valid parameters: "on", "off" |
837 | Default: "on" |
838 | |
839 | hisax= [HW,ISDN] |
840 | See Documentation/isdn/README.HiSax. |
841 | |
842 | hlt [BUGS=ARM,SH] |
843 | |
844 | hpet= [X86-32,HPET] option to control HPET usage |
845 | Format: { enable (default) | disable | force | |
846 | verbose } |
847 | disable: disable HPET and use PIT instead |
848 | force: allow force enabled of undocumented chips (ICH4, |
849 | VIA, nVidia) |
850 | verbose: show contents of HPET registers during setup |
851 | |
852 | hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. |
853 | hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. |
854 | On x86-64 and powerpc, this option can be specified |
855 | multiple times interleaved with hugepages= to reserve |
856 | huge pages of different sizes. Valid pages sizes on |
857 | x86-64 are 2M (when the CPU supports "pse") and 1G |
858 | (when the CPU supports the "pdpe1gb" cpuinfo flag) |
859 | Note that 1GB pages can only be allocated at boot time |
860 | using hugepages= and not freed afterwards. |
861 | |
862 | hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) |
863 | terminal devices. Valid values: 0..8 |
864 | hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. |
865 | If specified, z/VM IUCV HVC accepts connections |
866 | from listed z/VM user IDs only. |
867 | |
868 | i2c_bus= [HW] Override the default board specific I2C bus speed |
869 | or register an additional I2C bus that is not |
870 | registered from board initialization code. |
871 | Format: |
872 | <bus_id>,<clkrate> |
873 | |
874 | i8042.debug [HW] Toggle i8042 debug mode |
875 | i8042.direct [HW] Put keyboard port into non-translated mode |
876 | i8042.dumbkbd [HW] Pretend that controller can only read data from |
877 | keyboard and cannot control its state |
878 | (Don't attempt to blink the leds) |
879 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port |
880 | i8042.nokbd [HW] Don't check/create keyboard port |
881 | i8042.noloop [HW] Disable the AUX Loopback command while probing |
882 | for the AUX port |
883 | i8042.nomux [HW] Don't check presence of an active multiplexing |
884 | controller |
885 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX |
886 | controllers |
887 | i8042.reset [HW] Reset the controller during init and cleanup |
888 | i8042.unlock [HW] Unlock (ignore) the keylock |
889 | |
890 | i810= [HW,DRM] |
891 | |
892 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data |
893 | indicates that the driver is running on unsupported |
894 | hardware. |
895 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature |
896 | does not match list of supported models. |
897 | i8k.power_status |
898 | [HW] Report power status in /proc/i8k |
899 | (disabled by default) |
900 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN |
901 | capability is set. |
902 | |
903 | icn= [HW,ISDN] |
904 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] |
905 | |
906 | ide-core.nodma= [HW] (E)IDE subsystem |
907 | Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc |
908 | .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr |
909 | .cdrom .chs .ignore_cable are additional options |
910 | See Documentation/ide/ide.txt. |
911 | |
912 | ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem |
913 | Claim all unknown PCI IDE storage controllers. |
914 | |
915 | idle= [X86] |
916 | Format: idle=poll, idle=mwait, idle=halt, idle=nomwait |
917 | Poll forces a polling idle loop that can slightly |
918 | improve the performance of waking up a idle CPU, but |
919 | will use a lot of power and make the system run hot. |
920 | Not recommended. |
921 | idle=mwait: On systems which support MONITOR/MWAIT but |
922 | the kernel chose to not use it because it doesn't save |
923 | as much power as a normal idle loop, use the |
924 | MONITOR/MWAIT idle loop anyways. Performance should be |
925 | the same as idle=poll. |
926 | idle=halt: Halt is forced to be used for CPU idle. |
927 | In such case C2/C3 won't be used again. |
928 | idle=nomwait: Disable mwait for CPU C-states |
929 | |
930 | ignore_loglevel [KNL] |
931 | Ignore loglevel setting - this will print /all/ |
932 | kernel messages to the console. Useful for debugging. |
933 | |
934 | ihash_entries= [KNL] |
935 | Set number of hash buckets for inode cache. |
936 | |
937 | ima_audit= [IMA] |
938 | Format: { "0" | "1" } |
939 | 0 -- integrity auditing messages. (Default) |
940 | 1 -- enable informational integrity auditing messages. |
941 | |
942 | ima_hash= [IMA] |
943 | Format: { "sha1" | "md5" } |
944 | default: "sha1" |
945 | |
946 | ima_tcb [IMA] |
947 | Load a policy which meets the needs of the Trusted |
948 | Computing Base. This means IMA will measure all |
949 | programs exec'd, files mmap'd for exec, and all files |
950 | opened for read by uid=0. |
951 | |
952 | init= [KNL] |
953 | Format: <full_path> |
954 | Run specified binary instead of /sbin/init as init |
955 | process. |
956 | |
957 | initcall_debug [KNL] Trace initcalls as they are executed. Useful |
958 | for working out where the kernel is dying during |
959 | startup. |
960 | |
961 | initrd= [BOOT] Specify the location of the initial ramdisk |
962 | |
963 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver |
964 | Format: <irq> |
965 | |
966 | intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option |
967 | on |
968 | Enable intel iommu driver. |
969 | off |
970 | Disable intel iommu driver. |
971 | igfx_off [Default Off] |
972 | By default, gfx is mapped as normal device. If a gfx |
973 | device has a dedicated DMAR unit, the DMAR unit is |
974 | bypassed by not enabling DMAR with this option. In |
975 | this case, gfx device will use physical address for |
976 | DMA. |
977 | forcedac [x86_64] |
978 | With this option iommu will not optimize to look |
979 | for io virtual address below 32 bit forcing dual |
980 | address cycle on pci bus for cards supporting greater |
981 | than 32 bit addressing. The default is to look |
982 | for translation below 32 bit and if not available |
983 | then look in the higher range. |
984 | strict [Default Off] |
985 | With this option on every unmap_single operation will |
986 | result in a hardware IOTLB flush operation as opposed |
987 | to batching them for performance. |
988 | |
989 | intremap= [X86-64, Intel-IOMMU] |
990 | Format: { on (default) | off | nosid } |
991 | on enable Interrupt Remapping (default) |
992 | off disable Interrupt Remapping |
993 | nosid disable Source ID checking |
994 | |
995 | inttest= [IA64] |
996 | |
997 | iomem= Disable strict checking of access to MMIO memory |
998 | strict regions from userspace. |
999 | relaxed |
1000 | |
1001 | iommu= [x86] |
1002 | off |
1003 | force |
1004 | noforce |
1005 | biomerge |
1006 | panic |
1007 | nopanic |
1008 | merge |
1009 | nomerge |
1010 | forcesac |
1011 | soft |
1012 | pt [x86, IA64] |
1013 | |
1014 | io7= [HW] IO7 for Marvel based alpha systems |
1015 | See comment before marvel_specify_io7 in |
1016 | arch/alpha/kernel/core_marvel.c. |
1017 | |
1018 | io_delay= [X86] I/O delay method |
1019 | 0x80 |
1020 | Standard port 0x80 based delay |
1021 | 0xed |
1022 | Alternate port 0xed based delay (needed on some systems) |
1023 | udelay |
1024 | Simple two microseconds delay |
1025 | none |
1026 | No delay |
1027 | |
1028 | ip= [IP_PNP] |
1029 | See Documentation/filesystems/nfs/nfsroot.txt. |
1030 | |
1031 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards |
1032 | See comment before ip2_setup() in |
1033 | drivers/char/ip2/ip2base.c. |
1034 | |
1035 | irqfixup [HW] |
1036 | When an interrupt is not handled search all handlers |
1037 | for it. Intended to get systems with badly broken |
1038 | firmware running. |
1039 | |
1040 | irqpoll [HW] |
1041 | When an interrupt is not handled search all handlers |
1042 | for it. Also check all handlers each timer |
1043 | interrupt. Intended to get systems with badly broken |
1044 | firmware running. |
1045 | |
1046 | isapnp= [ISAPNP] |
1047 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> |
1048 | |
1049 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. |
1050 | Format: |
1051 | <cpu number>,...,<cpu number> |
1052 | or |
1053 | <cpu number>-<cpu number> |
1054 | (must be a positive range in ascending order) |
1055 | or a mixture |
1056 | <cpu number>,...,<cpu number>-<cpu number> |
1057 | |
1058 | This option can be used to specify one or more CPUs |
1059 | to isolate from the general SMP balancing and scheduling |
1060 | algorithms. You can move a process onto or off an |
1061 | "isolated" CPU via the CPU affinity syscalls or cpuset. |
1062 | <cpu number> begins at 0 and the maximum value is |
1063 | "number of CPUs in system - 1". |
1064 | |
1065 | This option is the preferred way to isolate CPUs. The |
1066 | alternative -- manually setting the CPU mask of all |
1067 | tasks in the system -- can cause problems and |
1068 | suboptimal load balancer performance. |
1069 | |
1070 | iucv= [HW,NET] |
1071 | |
1072 | js= [HW,JOY] Analog joystick |
1073 | See Documentation/input/joystick.txt. |
1074 | |
1075 | keepinitrd [HW,ARM] |
1076 | |
1077 | kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter |
1078 | specifies the amount of memory usable by the kernel |
1079 | for non-movable allocations. The requested amount is |
1080 | spread evenly throughout all nodes in the system. The |
1081 | remaining memory in each node is used for Movable |
1082 | pages. In the event, a node is too small to have both |
1083 | kernelcore and Movable pages, kernelcore pages will |
1084 | take priority and other nodes will have a larger number |
1085 | of kernelcore pages. The Movable zone is used for the |
1086 | allocation of pages that may be reclaimed or moved |
1087 | by the page migration subsystem. This means that |
1088 | HugeTLB pages may not be allocated from this zone. |
1089 | Note that allocations like PTEs-from-HighMem still |
1090 | use the HighMem zone if it exists, and the Normal |
1091 | zone if it does not. |
1092 | |
1093 | kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. |
1094 | Format: <Controller#>[,poll interval] |
1095 | The controller # is the number of the ehci usb debug |
1096 | port as it is probed via PCI. The poll interval is |
1097 | optional and is the number seconds in between |
1098 | each poll cycle to the debug port in case you need |
1099 | the functionality for interrupting the kernel with |
1100 | gdb or control-c on the dbgp connection. When |
1101 | not using this parameter you use sysrq-g to break into |
1102 | the kernel debugger. |
1103 | |
1104 | kgdboc= [KGDB,HW] kgdb over consoles. |
1105 | Requires a tty driver that supports console polling, |
1106 | or a supported polling keyboard driver (non-usb). |
1107 | Serial only format: <serial_device>[,baud] |
1108 | keyboard only format: kbd |
1109 | keyboard and serial format: kbd,<serial_device>[,baud] |
1110 | Optional Kernel mode setting: |
1111 | kms, kbd format: kms,kbd |
1112 | kms, kbd and serial format: kms,kbd,<ser_dev>[,baud] |
1113 | |
1114 | kgdbwait [KGDB] Stop kernel execution and enter the |
1115 | kernel debugger at the earliest opportunity. |
1116 | |
1117 | kmac= [MIPS] korina ethernet MAC address. |
1118 | Configure the RouterBoard 532 series on-chip |
1119 | Ethernet adapter MAC address. |
1120 | |
1121 | kmemleak= [KNL] Boot-time kmemleak enable/disable |
1122 | Valid arguments: on, off |
1123 | Default: on |
1124 | |
1125 | kstack=N [X86] Print N words from the kernel stack |
1126 | in oops dumps. |
1127 | |
1128 | kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. |
1129 | Default is 0 (don't ignore, but inject #GP) |
1130 | |
1131 | kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging. |
1132 | Default is 1 (enabled) |
1133 | |
1134 | kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit |
1135 | KVM MMU at runtime. |
1136 | Default is 0 (off) |
1137 | |
1138 | kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. |
1139 | Default is 1 (enabled) |
1140 | |
1141 | kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU) |
1142 | for all guests. |
1143 | Default is 1 (enabled) if in 64bit or 32bit-PAE mode |
1144 | |
1145 | kvm-intel.bypass_guest_pf= |
1146 | [KVM,Intel] Disables bypassing of guest page faults |
1147 | on Intel chips. Default is 1 (enabled) |
1148 | |
1149 | kvm-intel.ept= [KVM,Intel] Disable extended page tables |
1150 | (virtualized MMU) support on capable Intel chips. |
1151 | Default is 1 (enabled) |
1152 | |
1153 | kvm-intel.emulate_invalid_guest_state= |
1154 | [KVM,Intel] Enable emulation of invalid guest states |
1155 | Default is 0 (disabled) |
1156 | |
1157 | kvm-intel.flexpriority= |
1158 | [KVM,Intel] Disable FlexPriority feature (TPR shadow). |
1159 | Default is 1 (enabled) |
1160 | |
1161 | kvm-intel.unrestricted_guest= |
1162 | [KVM,Intel] Disable unrestricted guest feature |
1163 | (virtualized real and unpaged mode) on capable |
1164 | Intel chips. Default is 1 (enabled) |
1165 | |
1166 | kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification |
1167 | feature (tagged TLBs) on capable Intel chips. |
1168 | Default is 1 (enabled) |
1169 | |
1170 | l2cr= [PPC] |
1171 | |
1172 | l3cr= [PPC] |
1173 | |
1174 | lapic [X86-32,APIC] Enable the local APIC even if BIOS |
1175 | disabled it. |
1176 | |
1177 | lapic_timer_c2_ok [X86,APIC] trust the local apic timer |
1178 | in C2 power state. |
1179 | |
1180 | libata.dma= [LIBATA] DMA control |
1181 | libata.dma=0 Disable all PATA and SATA DMA |
1182 | libata.dma=1 PATA and SATA Disk DMA only |
1183 | libata.dma=2 ATAPI (CDROM) DMA only |
1184 | libata.dma=4 Compact Flash DMA only |
1185 | Combinations also work, so libata.dma=3 enables DMA |
1186 | for disks and CDROMs, but not CFs. |
1187 | |
1188 | libata.ignore_hpa= [LIBATA] Ignore HPA limit |
1189 | libata.ignore_hpa=0 keep BIOS limits (default) |
1190 | libata.ignore_hpa=1 ignore limits, using full disk |
1191 | |
1192 | libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume |
1193 | when set. |
1194 | Format: <int> |
1195 | |
1196 | libata.force= [LIBATA] Force configurations. The format is comma |
1197 | separated list of "[ID:]VAL" where ID is |
1198 | PORT[.DEVICE]. PORT and DEVICE are decimal numbers |
1199 | matching port, link or device. Basically, it matches |
1200 | the ATA ID string printed on console by libata. If |
1201 | the whole ID part is omitted, the last PORT and DEVICE |
1202 | values are used. If ID hasn't been specified yet, the |
1203 | configuration applies to all ports, links and devices. |
1204 | |
1205 | If only DEVICE is omitted, the parameter applies to |
1206 | the port and all links and devices behind it. DEVICE |
1207 | number of 0 either selects the first device or the |
1208 | first fan-out link behind PMP device. It does not |
1209 | select the host link. DEVICE number of 15 selects the |
1210 | host link and device attached to it. |
1211 | |
1212 | The VAL specifies the configuration to force. As long |
1213 | as there's no ambiguity shortcut notation is allowed. |
1214 | For example, both 1.5 and 1.5G would work for 1.5Gbps. |
1215 | The following configurations can be forced. |
1216 | |
1217 | * Cable type: 40c, 80c, short40c, unk, ign or sata. |
1218 | Any ID with matching PORT is used. |
1219 | |
1220 | * SATA link speed limit: 1.5Gbps or 3.0Gbps. |
1221 | |
1222 | * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7]. |
1223 | udma[/][16,25,33,44,66,100,133] notation is also |
1224 | allowed. |
1225 | |
1226 | * [no]ncq: Turn on or off NCQ. |
1227 | |
1228 | * nohrst, nosrst, norst: suppress hard, soft |
1229 | and both resets. |
1230 | |
1231 | * dump_id: dump IDENTIFY data. |
1232 | |
1233 | If there are multiple matching configurations changing |
1234 | the same attribute, the last one is used. |
1235 | |
1236 | memblock=debug [KNL] Enable memblock debug messages. |
1237 | |
1238 | load_ramdisk= [RAM] List of ramdisks to load from floppy |
1239 | See Documentation/blockdev/ramdisk.txt. |
1240 | |
1241 | lockd.nlm_grace_period=P [NFS] Assign grace period. |
1242 | Format: <integer> |
1243 | |
1244 | lockd.nlm_tcpport=N [NFS] Assign TCP port. |
1245 | Format: <integer> |
1246 | |
1247 | lockd.nlm_timeout=T [NFS] Assign timeout value. |
1248 | Format: <integer> |
1249 | |
1250 | lockd.nlm_udpport=M [NFS] Assign UDP port. |
1251 | Format: <integer> |
1252 | |
1253 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver |
1254 | Format: <irq> |
1255 | |
1256 | loglevel= All Kernel Messages with a loglevel smaller than the |
1257 | console loglevel will be printed to the console. It can |
1258 | also be changed with klogd or other programs. The |
1259 | loglevels are defined as follows: |
1260 | |
1261 | 0 (KERN_EMERG) system is unusable |
1262 | 1 (KERN_ALERT) action must be taken immediately |
1263 | 2 (KERN_CRIT) critical conditions |
1264 | 3 (KERN_ERR) error conditions |
1265 | 4 (KERN_WARNING) warning conditions |
1266 | 5 (KERN_NOTICE) normal but significant condition |
1267 | 6 (KERN_INFO) informational |
1268 | 7 (KERN_DEBUG) debug-level messages |
1269 | |
1270 | log_buf_len=n Sets the size of the printk ring buffer, in bytes. |
1271 | Format: { n | nk | nM } |
1272 | n must be a power of two. The default size |
1273 | is set in the kernel config file. |
1274 | |
1275 | logo.nologo [FB] Disables display of the built-in Linux logo. |
1276 | This may be used to provide more screen space for |
1277 | kernel log messages and is useful when debugging |
1278 | kernel boot problems. |
1279 | |
1280 | lp=0 [LP] Specify parallel ports to use, e.g, |
1281 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses |
1282 | lp=reset first parallel port). 'lp=0' disables the |
1283 | lp=auto printer driver. 'lp=reset' (which can be |
1284 | specified in addition to the ports) causes |
1285 | attached printers to be reset. Using |
1286 | lp=port1,port2,... specifies the parallel ports |
1287 | to associate lp devices with, starting with |
1288 | lp0. A port specification may be 'none' to skip |
1289 | that lp device, or a parport name such as |
1290 | 'parport0'. Specifying 'lp=auto' instead of a |
1291 | port specification list means that device IDs |
1292 | from each port should be examined, to see if |
1293 | an IEEE 1284-compliant printer is attached; if |
1294 | so, the driver will manage that printer. |
1295 | See also header of drivers/char/lp.c. |
1296 | |
1297 | lpj=n [KNL] |
1298 | Sets loops_per_jiffy to given constant, thus avoiding |
1299 | time-consuming boot-time autodetection (up to 250 ms per |
1300 | CPU). 0 enables autodetection (default). To determine |
1301 | the correct value for your kernel, boot with normal |
1302 | autodetection and see what value is printed. Note that |
1303 | on SMP systems the preset will be applied to all CPUs, |
1304 | which is likely to cause problems if your CPUs need |
1305 | significantly divergent settings. An incorrect value |
1306 | will cause delays in the kernel to be wrong, leading to |
1307 | unpredictable I/O errors and other breakage. Although |
1308 | unlikely, in the extreme case this might damage your |
1309 | hardware. |
1310 | |
1311 | ltpc= [NET] |
1312 | Format: <io>,<irq>,<dma> |
1313 | |
1314 | machvec= [IA64] Force the use of a particular machine-vector |
1315 | (machvec) in a generic kernel. |
1316 | Example: machvec=hpzx1_swiotlb |
1317 | |
1318 | machtype= [Loongson] Share the same kernel image file between different |
1319 | yeeloong laptop. |
1320 | Example: machtype=lemote-yeeloong-2f-7inch |
1321 | |
1322 | max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater |
1323 | than or equal to this physical address is ignored. |
1324 | |
1325 | maxcpus= [SMP] Maximum number of processors that an SMP kernel |
1326 | should make use of. maxcpus=n : n >= 0 limits the |
1327 | kernel to using 'n' processors. n=0 is a special case, |
1328 | it is equivalent to "nosmp", which also disables |
1329 | the IO APIC. |
1330 | |
1331 | max_loop= [LOOP] Maximum number of loopback devices that can |
1332 | be mounted |
1333 | Format: <1-256> |
1334 | |
1335 | mcatest= [IA-64] |
1336 | |
1337 | mce [X86-32] Machine Check Exception |
1338 | |
1339 | mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt |
1340 | |
1341 | md= [HW] RAID subsystems devices and level |
1342 | See Documentation/md.txt. |
1343 | |
1344 | mdacon= [MDA] |
1345 | Format: <first>,<last> |
1346 | Specifies range of consoles to be captured by the MDA. |
1347 | |
1348 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory |
1349 | Amount of memory to be used when the kernel is not able |
1350 | to see the whole system memory or for test. |
1351 | [X86-32] Use together with memmap= to avoid physical |
1352 | address space collisions. Without memmap= PCI devices |
1353 | could be placed at addresses belonging to unused RAM. |
1354 | |
1355 | mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel |
1356 | memory. |
1357 | |
1358 | memchunk=nn[KMG] |
1359 | [KNL,SH] Allow user to override the default size for |
1360 | per-device physically contiguous DMA buffers. |
1361 | |
1362 | memmap=exactmap [KNL,X86] Enable setting of an exact |
1363 | E820 memory map, as specified by the user. |
1364 | Such memmap=exactmap lines can be constructed based on |
1365 | BIOS output or other requirements. See the memmap=nn@ss |
1366 | option description. |
1367 | |
1368 | memmap=nn[KMG]@ss[KMG] |
1369 | [KNL] Force usage of a specific region of memory |
1370 | Region of memory to be used, from ss to ss+nn. |
1371 | |
1372 | memmap=nn[KMG]#ss[KMG] |
1373 | [KNL,ACPI] Mark specific memory as ACPI data. |
1374 | Region of memory to be used, from ss to ss+nn. |
1375 | |
1376 | memmap=nn[KMG]$ss[KMG] |
1377 | [KNL,ACPI] Mark specific memory as reserved. |
1378 | Region of memory to be used, from ss to ss+nn. |
1379 | Example: Exclude memory from 0x18690000-0x1869ffff |
1380 | memmap=64K$0x18690000 |
1381 | or |
1382 | memmap=0x10000$0x18690000 |
1383 | |
1384 | memory_corruption_check=0/1 [X86] |
1385 | Some BIOSes seem to corrupt the first 64k of |
1386 | memory when doing things like suspend/resume. |
1387 | Setting this option will scan the memory |
1388 | looking for corruption. Enabling this will |
1389 | both detect corruption and prevent the kernel |
1390 | from using the memory being corrupted. |
1391 | However, its intended as a diagnostic tool; if |
1392 | repeatable BIOS-originated corruption always |
1393 | affects the same memory, you can use memmap= |
1394 | to prevent the kernel from using that memory. |
1395 | |
1396 | memory_corruption_check_size=size [X86] |
1397 | By default it checks for corruption in the low |
1398 | 64k, making this memory unavailable for normal |
1399 | use. Use this parameter to scan for |
1400 | corruption in more or less memory. |
1401 | |
1402 | memory_corruption_check_period=seconds [X86] |
1403 | By default it checks for corruption every 60 |
1404 | seconds. Use this parameter to check at some |
1405 | other rate. 0 disables periodic checking. |
1406 | |
1407 | memtest= [KNL,X86] Enable memtest |
1408 | Format: <integer> |
1409 | default : 0 <disable> |
1410 | Specifies the number of memtest passes to be |
1411 | performed. Each pass selects another test |
1412 | pattern from a given set of patterns. Memtest |
1413 | fills the memory with this pattern, validates |
1414 | memory contents and reserves bad memory |
1415 | regions that are detected. |
1416 | |
1417 | meye.*= [HW] Set MotionEye Camera parameters |
1418 | See Documentation/video4linux/meye.txt. |
1419 | |
1420 | mfgpt_irq= [IA-32] Specify the IRQ to use for the |
1421 | Multi-Function General Purpose Timers on AMD Geode |
1422 | platforms. |
1423 | |
1424 | mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when |
1425 | the BIOS has incorrectly applied a workaround. TinyBIOS |
1426 | version 0.98 is known to be affected, 0.99 fixes the |
1427 | problem by letting the user disable the workaround. |
1428 | |
1429 | mga= [HW,DRM] |
1430 | |
1431 | min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this |
1432 | physical address is ignored. |
1433 | |
1434 | mini2440= [ARM,HW,KNL] |
1435 | Format:[0..2][b][c][t] |
1436 | Default: "0tb" |
1437 | MINI2440 configuration specification: |
1438 | 0 - The attached screen is the 3.5" TFT |
1439 | 1 - The attached screen is the 7" TFT |
1440 | 2 - The VGA Shield is attached (1024x768) |
1441 | Leaving out the screen size parameter will not load |
1442 | the TFT driver, and the framebuffer will be left |
1443 | unconfigured. |
1444 | b - Enable backlight. The TFT backlight pin will be |
1445 | linked to the kernel VESA blanking code and a GPIO |
1446 | LED. This parameter is not necessary when using the |
1447 | VGA shield. |
1448 | c - Enable the s3c camera interface. |
1449 | t - Reserved for enabling touchscreen support. The |
1450 | touchscreen support is not enabled in the mainstream |
1451 | kernel as of 2.6.30, a preliminary port can be found |
1452 | in the "bleeding edge" mini2440 support kernel at |
1453 | http://repo.or.cz/w/linux-2.6/mini2440.git |
1454 | |
1455 | mminit_loglevel= |
1456 | [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this |
1457 | parameter allows control of the logging verbosity for |
1458 | the additional memory initialisation checks. A value |
1459 | of 0 disables mminit logging and a level of 4 will |
1460 | log everything. Information is printed at KERN_DEBUG |
1461 | so loglevel=8 may also need to be specified. |
1462 | |
1463 | mousedev.tap_time= |
1464 | [MOUSE] Maximum time between finger touching and |
1465 | leaving touchpad surface for touch to be considered |
1466 | a tap and be reported as a left button click (for |
1467 | touchpads working in absolute mode only). |
1468 | Format: <msecs> |
1469 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices |
1470 | reporting absolute coordinates, such as tablets |
1471 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices |
1472 | reporting absolute coordinates, such as tablets |
1473 | |
1474 | movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter |
1475 | is similar to kernelcore except it specifies the |
1476 | amount of memory used for migratable allocations. |
1477 | If both kernelcore and movablecore is specified, |
1478 | then kernelcore will be at *least* the specified |
1479 | value but may be more. If movablecore on its own |
1480 | is specified, the administrator must be careful |
1481 | that the amount of memory usable for all allocations |
1482 | is not too small. |
1483 | |
1484 | MTD_Partition= [MTD] |
1485 | Format: <name>,<region-number>,<size>,<offset> |
1486 | |
1487 | MTD_Region= [MTD] Format: |
1488 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] |
1489 | |
1490 | mtdparts= [MTD] |
1491 | See drivers/mtd/cmdlinepart.c. |
1492 | |
1493 | onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration |
1494 | |
1495 | Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock] |
1496 | |
1497 | boundary - index of last SLC block on Flex-OneNAND. |
1498 | The remaining blocks are configured as MLC blocks. |
1499 | lock - Configure if Flex-OneNAND boundary should be locked. |
1500 | Once locked, the boundary cannot be changed. |
1501 | 1 indicates lock status, 0 indicates unlock status. |
1502 | |
1503 | mtdset= [ARM] |
1504 | ARM/S3C2412 JIVE boot control |
1505 | |
1506 | See arch/arm/mach-s3c2412/mach-jive.c |
1507 | |
1508 | mtouchusb.raw_coordinates= |
1509 | [HW] Make the MicroTouch USB driver use raw coordinates |
1510 | ('y', default) or cooked coordinates ('n') |
1511 | |
1512 | mtrr_chunk_size=nn[KMG] [X86] |
1513 | used for mtrr cleanup. It is largest continuous chunk |
1514 | that could hold holes aka. UC entries. |
1515 | |
1516 | mtrr_gran_size=nn[KMG] [X86] |
1517 | Used for mtrr cleanup. It is granularity of mtrr block. |
1518 | Default is 1. |
1519 | Large value could prevent small alignment from |
1520 | using up MTRRs. |
1521 | |
1522 | mtrr_spare_reg_nr=n [X86] |
1523 | Format: <integer> |
1524 | Range: 0,7 : spare reg number |
1525 | Default : 1 |
1526 | Used for mtrr cleanup. It is spare mtrr entries number. |
1527 | Set to 2 or more if your graphical card needs more. |
1528 | |
1529 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card |
1530 | |
1531 | netdev= [NET] Network devices parameters |
1532 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> |
1533 | Note that mem_start is often overloaded to mean |
1534 | something different and driver-specific. |
1535 | This usage is only documented in each driver source |
1536 | file if at all. |
1537 | |
1538 | nf_conntrack.acct= |
1539 | [NETFILTER] Enable connection tracking flow accounting |
1540 | 0 to disable accounting |
1541 | 1 to enable accounting |
1542 | Default value is 0. |
1543 | |
1544 | nfsaddrs= [NFS] Deprecated. Use ip= instead. |
1545 | See Documentation/filesystems/nfs/nfsroot.txt. |
1546 | |
1547 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. |
1548 | See Documentation/filesystems/nfs/nfsroot.txt. |
1549 | |
1550 | nfsrootdebug [NFS] enable nfsroot debugging messages. |
1551 | See Documentation/filesystems/nfs/nfsroot.txt. |
1552 | |
1553 | nfs.callback_tcpport= |
1554 | [NFS] set the TCP port on which the NFSv4 callback |
1555 | channel should listen. |
1556 | |
1557 | nfs.cache_getent= |
1558 | [NFS] sets the pathname to the program which is used |
1559 | to update the NFS client cache entries. |
1560 | |
1561 | nfs.cache_getent_timeout= |
1562 | [NFS] sets the timeout after which an attempt to |
1563 | update a cache entry is deemed to have failed. |
1564 | |
1565 | nfs.idmap_cache_timeout= |
1566 | [NFS] set the maximum lifetime for idmapper cache |
1567 | entries. |
1568 | |
1569 | nfs.enable_ino64= |
1570 | [NFS] enable 64-bit inode numbers. |
1571 | If zero, the NFS client will fake up a 32-bit inode |
1572 | number for the readdir() and stat() syscalls instead |
1573 | of returning the full 64-bit number. |
1574 | The default is to return 64-bit inode numbers. |
1575 | |
1576 | nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take |
1577 | when a NMI is triggered. |
1578 | Format: [state][,regs][,debounce][,die] |
1579 | |
1580 | nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels |
1581 | Format: [panic,][num] |
1582 | Valid num: 0,1,2 |
1583 | 0 - turn nmi_watchdog off |
1584 | 1 - use the IO-APIC timer for the NMI watchdog |
1585 | 2 - use the local APIC for the NMI watchdog using |
1586 | a performance counter. Note: This will use one |
1587 | performance counter and the local APIC's performance |
1588 | vector. |
1589 | When panic is specified, panic when an NMI watchdog |
1590 | timeout occurs. |
1591 | This is useful when you use a panic=... timeout and |
1592 | need the box quickly up again. |
1593 | Instead of 1 and 2 it is possible to use the following |
1594 | symbolic names: lapic and ioapic |
1595 | Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic |
1596 | |
1597 | netpoll.carrier_timeout= |
1598 | [NET] Specifies amount of time (in seconds) that |
1599 | netpoll should wait for a carrier. By default netpoll |
1600 | waits 4 seconds. |
1601 | |
1602 | no387 [BUGS=X86-32] Tells the kernel to use the 387 maths |
1603 | emulation library even if a 387 maths coprocessor |
1604 | is present. |
1605 | |
1606 | no_console_suspend |
1607 | [HW] Never suspend the console |
1608 | Disable suspending of consoles during suspend and |
1609 | hibernate operations. Once disabled, debugging |
1610 | messages can reach various consoles while the rest |
1611 | of the system is being put to sleep (ie, while |
1612 | debugging driver suspend/resume hooks). This may |
1613 | not work reliably with all consoles, but is known |
1614 | to work with serial and VGA consoles. |
1615 | |
1616 | noaliencache [MM, NUMA, SLAB] Disables the allocation of alien |
1617 | caches in the slab allocator. Saves per-node memory, |
1618 | but will impact performance. |
1619 | |
1620 | noalign [KNL,ARM] |
1621 | |
1622 | noapic [SMP,APIC] Tells the kernel to not make use of any |
1623 | IOAPICs that may be present in the system. |
1624 | |
1625 | nobats [PPC] Do not use BATs for mapping kernel lowmem |
1626 | on "Classic" PPC cores. |
1627 | |
1628 | nocache [ARM] |
1629 | |
1630 | noclflush [BUGS=X86] Don't use the CLFLUSH instruction |
1631 | |
1632 | nodelayacct [KNL] Disable per-task delay accounting |
1633 | |
1634 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. |
1635 | |
1636 | nodsp [SH] Disable hardware DSP at boot time. |
1637 | |
1638 | noefi [X86] Disable EFI runtime services support. |
1639 | |
1640 | noexec [IA-64] |
1641 | |
1642 | noexec [X86] |
1643 | On X86-32 available only on PAE configured kernels. |
1644 | noexec=on: enable non-executable mappings (default) |
1645 | noexec=off: disable non-executable mappings |
1646 | |
1647 | noexec32 [X86-64] |
1648 | This affects only 32-bit executables. |
1649 | noexec32=on: enable non-executable mappings (default) |
1650 | read doesn't imply executable mappings |
1651 | noexec32=off: disable non-executable mappings |
1652 | read implies executable mappings |
1653 | |
1654 | nofpu [SH] Disable hardware FPU at boot time. |
1655 | |
1656 | nofxsr [BUGS=X86-32] Disables x86 floating point extended |
1657 | register save and restore. The kernel will only save |
1658 | legacy floating-point registers on task switch. |
1659 | |
1660 | noxsave [BUGS=X86] Disables x86 extended register state save |
1661 | and restore using xsave. The kernel will fallback to |
1662 | enabling legacy floating-point and sse state. |
1663 | |
1664 | nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or |
1665 | wfi(ARM) instruction doesn't work correctly and not to |
1666 | use it. This is also useful when using JTAG debugger. |
1667 | |
1668 | no-hlt [BUGS=X86-32] Tells the kernel that the hlt |
1669 | instruction doesn't work correctly and not to |
1670 | use it. |
1671 | |
1672 | no_file_caps Tells the kernel not to honor file capabilities. The |
1673 | only way then for a file to be executed with privilege |
1674 | is to be setuid root or executed by root. |
1675 | |
1676 | nohalt [IA-64] Tells the kernel not to use the power saving |
1677 | function PAL_HALT_LIGHT when idle. This increases |
1678 | power-consumption. On the positive side, it reduces |
1679 | interrupt wake-up latency, which may improve performance |
1680 | in certain environments such as networked servers or |
1681 | real-time systems. |
1682 | |
1683 | nohz= [KNL] Boottime enable/disable dynamic ticks |
1684 | Valid arguments: on, off |
1685 | Default: on |
1686 | |
1687 | noiotrap [SH] Disables trapped I/O port accesses. |
1688 | |
1689 | noirqdebug [X86-32] Disables the code which attempts to detect and |
1690 | disable unhandled interrupt sources. |
1691 | |
1692 | no_timer_check [X86,APIC] Disables the code which tests for |
1693 | broken timer IRQ sources. |
1694 | |
1695 | noisapnp [ISAPNP] Disables ISA PnP code. |
1696 | |
1697 | noinitrd [RAM] Tells the kernel not to load any configured |
1698 | initial RAM disk. |
1699 | |
1700 | nointremap [X86-64, Intel-IOMMU] Do not enable interrupt |
1701 | remapping. |
1702 | [Deprecated - use intremap=off] |
1703 | |
1704 | nointroute [IA-64] |
1705 | |
1706 | nojitter [IA64] Disables jitter checking for ITC timers. |
1707 | |
1708 | no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver |
1709 | |
1710 | nolapic [X86-32,APIC] Do not enable or use the local APIC. |
1711 | |
1712 | nolapic_timer [X86-32,APIC] Do not use the local APIC timer. |
1713 | |
1714 | noltlbs [PPC] Do not use large page/tlb entries for kernel |
1715 | lowmem mapping on PPC40x. |
1716 | |
1717 | nomca [IA-64] Disable machine check abort handling |
1718 | |
1719 | nomce [X86-32] Machine Check Exception |
1720 | |
1721 | nomfgpt [X86-32] Disable Multi-Function General Purpose |
1722 | Timer usage (for AMD Geode machines). |
1723 | |
1724 | nopat [X86] Disable PAT (page attribute table extension of |
1725 | pagetables) support. |
1726 | |
1727 | norandmaps Don't use address space randomization. Equivalent to |
1728 | echo 0 > /proc/sys/kernel/randomize_va_space |
1729 | |
1730 | noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops |
1731 | |
1732 | noreplace-smp [X86-32,SMP] Don't replace SMP instructions |
1733 | with UP alternatives |
1734 | |
1735 | noresidual [PPC] Don't use residual data on PReP machines. |
1736 | |
1737 | noresume [SWSUSP] Disables resume and restores original swap |
1738 | space. |
1739 | |
1740 | no-scroll [VGA] Disables scrollback. |
1741 | This is required for the Braillex ib80-piezo Braille |
1742 | reader made by F.H. Papenmeier (Germany). |
1743 | |
1744 | nosbagart [IA-64] |
1745 | |
1746 | nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. |
1747 | |
1748 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel, |
1749 | and disable the IO APIC. legacy for "maxcpus=0". |
1750 | |
1751 | nosoftlockup [KNL] Disable the soft-lockup detector. |
1752 | |
1753 | noswapaccount [KNL] Disable accounting of swap in memory resource |
1754 | controller. (See Documentation/cgroups/memory.txt) |
1755 | |
1756 | nosync [HW,M68K] Disables sync negotiation for all devices. |
1757 | |
1758 | notsc [BUGS=X86-32] Disable Time Stamp Counter |
1759 | |
1760 | nousb [USB] Disable the USB subsystem |
1761 | |
1762 | nowatchdog [KNL] Disable the lockup detector (NMI watchdog). |
1763 | |
1764 | nowb [ARM] |
1765 | |
1766 | nox2apic [X86-64,APIC] Do not enable x2APIC mode. |
1767 | |
1768 | nptcg= [IA64] Override max number of concurrent global TLB |
1769 | purges which is reported from either PAL_VM_SUMMARY or |
1770 | SAL PALO. |
1771 | |
1772 | nr_cpus= [SMP] Maximum number of processors that an SMP kernel |
1773 | could support. nr_cpus=n : n >= 1 limits the kernel to |
1774 | supporting 'n' processors. Later in runtime you can not |
1775 | use hotplug cpu feature to put more cpu back to online. |
1776 | just like you compile the kernel NR_CPUS=n |
1777 | |
1778 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. |
1779 | |
1780 | numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. |
1781 | one of ['zone', 'node', 'default'] can be specified |
1782 | This can be set from sysctl after boot. |
1783 | See Documentation/sysctl/vm.txt for details. |
1784 | |
1785 | ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. |
1786 | See Documentation/debugging-via-ohci1394.txt for more |
1787 | info. |
1788 | |
1789 | olpc_ec_timeout= [OLPC] ms delay when issuing EC commands |
1790 | Rather than timing out after 20 ms if an EC |
1791 | command is not properly ACKed, override the length |
1792 | of the timeout. We have interrupts disabled while |
1793 | waiting for the ACK, so if this is set too high |
1794 | interrupts *may* be lost! |
1795 | |
1796 | omap_mux= [OMAP] Override bootloader pin multiplexing. |
1797 | Format: <mux_mode0.mode_name=value>... |
1798 | For example, to override I2C bus2: |
1799 | omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100 |
1800 | |
1801 | oprofile.timer= [HW] |
1802 | Use timer interrupt instead of performance counters |
1803 | |
1804 | oprofile.cpu_type= Force an oprofile cpu type |
1805 | This might be useful if you have an older oprofile |
1806 | userland or if you want common events. |
1807 | Format: { arch_perfmon } |
1808 | arch_perfmon: [X86] Force use of architectural |
1809 | perfmon on Intel CPUs instead of the |
1810 | CPU specific event set. |
1811 | |
1812 | OSS [HW,OSS] |
1813 | See Documentation/sound/oss/oss-parameters.txt |
1814 | |
1815 | panic= [KNL] Kernel behaviour on panic |
1816 | Format: <timeout> |
1817 | |
1818 | parkbd.port= [HW] Parallel port number the keyboard adapter is |
1819 | connected to, default is 0. |
1820 | Format: <parport#> |
1821 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, |
1822 | 0 for XT, 1 for AT (default is AT). |
1823 | Format: <mode> |
1824 | |
1825 | parport= [HW,PPT] Specify parallel ports. 0 disables. |
1826 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } |
1827 | Use 'auto' to force the driver to use any |
1828 | IRQ/DMA settings detected (the default is to |
1829 | ignore detected IRQ/DMA settings because of |
1830 | possible conflicts). You can specify the base |
1831 | address, IRQ, and DMA settings; IRQ and DMA |
1832 | should be numbers, or 'auto' (for using detected |
1833 | settings on that particular port), or 'nofifo' |
1834 | (to avoid using a FIFO even if it is detected). |
1835 | Parallel ports are assigned in the order they |
1836 | are specified on the command line, starting |
1837 | with parport0. |
1838 | |
1839 | parport_init_mode= [HW,PPT] |
1840 | Configure VIA parallel port to operate in |
1841 | a specific mode. This is necessary on Pegasos |
1842 | computer where firmware has no options for setting |
1843 | up parallel port mode and sets it to spp. |
1844 | Currently this function knows 686a and 8231 chips. |
1845 | Format: [spp|ps2|epp|ecp|ecpepp] |
1846 | |
1847 | pause_on_oops= |
1848 | Halt all CPUs after the first oops has been printed for |
1849 | the specified number of seconds. This is to be used if |
1850 | your oopses keep scrolling off the screen. |
1851 | |
1852 | pcbit= [HW,ISDN] |
1853 | |
1854 | pcd. [PARIDE] |
1855 | See header of drivers/block/paride/pcd.c. |
1856 | See also Documentation/blockdev/paride.txt. |
1857 | |
1858 | pci=option[,option...] [PCI] various PCI subsystem options: |
1859 | earlydump [X86] dump PCI config space before the kernel |
1860 | changes anything |
1861 | off [X86] don't probe for the PCI bus |
1862 | bios [X86-32] force use of PCI BIOS, don't access |
1863 | the hardware directly. Use this if your machine |
1864 | has a non-standard PCI host bridge. |
1865 | nobios [X86-32] disallow use of PCI BIOS, only direct |
1866 | hardware access methods are allowed. Use this |
1867 | if you experience crashes upon bootup and you |
1868 | suspect they are caused by the BIOS. |
1869 | conf1 [X86] Force use of PCI Configuration |
1870 | Mechanism 1. |
1871 | conf2 [X86] Force use of PCI Configuration |
1872 | Mechanism 2. |
1873 | noaer [PCIE] If the PCIEAER kernel config parameter is |
1874 | enabled, this kernel boot option can be used to |
1875 | disable the use of PCIE advanced error reporting. |
1876 | nodomains [PCI] Disable support for multiple PCI |
1877 | root domains (aka PCI segments, in ACPI-speak). |
1878 | nommconf [X86] Disable use of MMCONFIG for PCI |
1879 | Configuration |
1880 | check_enable_amd_mmconf [X86] check for and enable |
1881 | properly configured MMIO access to PCI |
1882 | config space on AMD family 10h CPU |
1883 | nomsi [MSI] If the PCI_MSI kernel config parameter is |
1884 | enabled, this kernel boot option can be used to |
1885 | disable the use of MSI interrupts system-wide. |
1886 | noioapicquirk [APIC] Disable all boot interrupt quirks. |
1887 | Safety option to keep boot IRQs enabled. This |
1888 | should never be necessary. |
1889 | ioapicreroute [APIC] Enable rerouting of boot IRQs to the |
1890 | primary IO-APIC for bridges that cannot disable |
1891 | boot IRQs. This fixes a source of spurious IRQs |
1892 | when the system masks IRQs. |
1893 | noioapicreroute [APIC] Disable workaround that uses the |
1894 | boot IRQ equivalent of an IRQ that connects to |
1895 | a chipset where boot IRQs cannot be disabled. |
1896 | The opposite of ioapicreroute. |
1897 | biosirq [X86-32] Use PCI BIOS calls to get the interrupt |
1898 | routing table. These calls are known to be buggy |
1899 | on several machines and they hang the machine |
1900 | when used, but on other computers it's the only |
1901 | way to get the interrupt routing table. Try |
1902 | this option if the kernel is unable to allocate |
1903 | IRQs or discover secondary PCI buses on your |
1904 | motherboard. |
1905 | rom [X86] Assign address space to expansion ROMs. |
1906 | Use with caution as certain devices share |
1907 | address decoders between ROMs and other |
1908 | resources. |
1909 | norom [X86] Do not assign address space to |
1910 | expansion ROMs that do not already have |
1911 | BIOS assigned address ranges. |
1912 | nobar [X86] Do not assign address space to the |
1913 | BARs that weren't assigned by the BIOS. |
1914 | irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be |
1915 | assigned automatically to PCI devices. You can |
1916 | make the kernel exclude IRQs of your ISA cards |
1917 | this way. |
1918 | pirqaddr=0xAAAAA [X86] Specify the physical address |
1919 | of the PIRQ table (normally generated |
1920 | by the BIOS) if it is outside the |
1921 | F0000h-100000h range. |
1922 | lastbus=N [X86] Scan all buses thru bus #N. Can be |
1923 | useful if the kernel is unable to find your |
1924 | secondary buses and you want to tell it |
1925 | explicitly which ones they are. |
1926 | assign-busses [X86] Always assign all PCI bus |
1927 | numbers ourselves, overriding |
1928 | whatever the firmware may have done. |
1929 | usepirqmask [X86] Honor the possible IRQ mask stored |
1930 | in the BIOS $PIR table. This is needed on |
1931 | some systems with broken BIOSes, notably |
1932 | some HP Pavilion N5400 and Omnibook XE3 |
1933 | notebooks. This will have no effect if ACPI |
1934 | IRQ routing is enabled. |
1935 | noacpi [X86] Do not use ACPI for IRQ routing |
1936 | or for PCI scanning. |
1937 | use_crs [X86] Use PCI host bridge window information |
1938 | from ACPI. On BIOSes from 2008 or later, this |
1939 | is enabled by default. If you need to use this, |
1940 | please report a bug. |
1941 | nocrs [X86] Ignore PCI host bridge windows from ACPI. |
1942 | If you need to use this, please report a bug. |
1943 | routeirq Do IRQ routing for all PCI devices. |
1944 | This is normally done in pci_enable_device(), |
1945 | so this option is a temporary workaround |
1946 | for broken drivers that don't call it. |
1947 | skip_isa_align [X86] do not align io start addr, so can |
1948 | handle more pci cards |
1949 | firmware [ARM] Do not re-enumerate the bus but instead |
1950 | just use the configuration from the |
1951 | bootloader. This is currently used on |
1952 | IXP2000 systems where the bus has to be |
1953 | configured a certain way for adjunct CPUs. |
1954 | noearly [X86] Don't do any early type 1 scanning. |
1955 | This might help on some broken boards which |
1956 | machine check when some devices' config space |
1957 | is read. But various workarounds are disabled |
1958 | and some IOMMU drivers will not work. |
1959 | bfsort Sort PCI devices into breadth-first order. |
1960 | This sorting is done to get a device |
1961 | order compatible with older (<= 2.4) kernels. |
1962 | nobfsort Don't sort PCI devices into breadth-first order. |
1963 | cbiosize=nn[KMG] The fixed amount of bus space which is |
1964 | reserved for the CardBus bridge's IO window. |
1965 | The default value is 256 bytes. |
1966 | cbmemsize=nn[KMG] The fixed amount of bus space which is |
1967 | reserved for the CardBus bridge's memory |
1968 | window. The default value is 64 megabytes. |
1969 | resource_alignment= |
1970 | Format: |
1971 | [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] |
1972 | Specifies alignment and device to reassign |
1973 | aligned memory resources. |
1974 | If <order of align> is not specified, |
1975 | PAGE_SIZE is used as alignment. |
1976 | PCI-PCI bridge can be specified, if resource |
1977 | windows need to be expanded. |
1978 | ecrc= Enable/disable PCIe ECRC (transaction layer |
1979 | end-to-end CRC checking). |
1980 | bios: Use BIOS/firmware settings. This is the |
1981 | the default. |
1982 | off: Turn ECRC off |
1983 | on: Turn ECRC on. |
1984 | |
1985 | pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power |
1986 | Management. |
1987 | off Disable ASPM. |
1988 | force Enable ASPM even on devices that claim not to support it. |
1989 | WARNING: Forcing ASPM on may cause system lockups. |
1990 | |
1991 | pcie_ports= [PCIE] PCIe ports handling: |
1992 | auto Ask the BIOS whether or not to use native PCIe services |
1993 | associated with PCIe ports (PME, hot-plug, AER). Use |
1994 | them only if that is allowed by the BIOS. |
1995 | native Use native PCIe services associated with PCIe ports |
1996 | unconditionally. |
1997 | compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe |
1998 | ports driver. |
1999 | |
2000 | pcie_pme= [PCIE,PM] Native PCIe PME signaling options: |
2001 | nomsi Do not use MSI for native PCIe PME signaling (this makes |
2002 | all PCIe root ports use INTx for all services). |
2003 | |
2004 | pcmv= [HW,PCMCIA] BadgePAD 4 |
2005 | |
2006 | pd. [PARIDE] |
2007 | See Documentation/blockdev/paride.txt. |
2008 | |
2009 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at |
2010 | boot time. |
2011 | Format: { 0 | 1 } |
2012 | See arch/parisc/kernel/pdc_chassis.c |
2013 | |
2014 | percpu_alloc= Select which percpu first chunk allocator to use. |
2015 | Currently supported values are "embed" and "page". |
2016 | Archs may support subset or none of the selections. |
2017 | See comments in mm/percpu.c for details on each |
2018 | allocator. This parameter is primarily for debugging |
2019 | and performance comparison. |
2020 | |
2021 | pf. [PARIDE] |
2022 | See Documentation/blockdev/paride.txt. |
2023 | |
2024 | pg. [PARIDE] |
2025 | See Documentation/blockdev/paride.txt. |
2026 | |
2027 | pirq= [SMP,APIC] Manual mp-table setup |
2028 | See Documentation/x86/i386/IO-APIC.txt. |
2029 | |
2030 | plip= [PPT,NET] Parallel port network link |
2031 | Format: { parport<nr> | timid | 0 } |
2032 | See also Documentation/parport.txt. |
2033 | |
2034 | pmtmr= [X86] Manual setup of pmtmr I/O Port. |
2035 | Override pmtimer IOPort with a hex value. |
2036 | e.g. pmtmr=0x508 |
2037 | |
2038 | pnp.debug [PNP] |
2039 | Enable PNP debug messages. This depends on the |
2040 | CONFIG_PNP_DEBUG_MESSAGES option. |
2041 | |
2042 | pnpacpi= [ACPI] |
2043 | { off } |
2044 | |
2045 | pnpbios= [ISAPNP] |
2046 | { on | off | curr | res | no-curr | no-res } |
2047 | |
2048 | pnp_reserve_irq= |
2049 | [ISAPNP] Exclude IRQs for the autoconfiguration |
2050 | |
2051 | pnp_reserve_dma= |
2052 | [ISAPNP] Exclude DMAs for the autoconfiguration |
2053 | |
2054 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration |
2055 | Ranges are in pairs (I/O port base and size). |
2056 | |
2057 | pnp_reserve_mem= |
2058 | [ISAPNP] Exclude memory regions for the |
2059 | autoconfiguration. |
2060 | Ranges are in pairs (memory base and size). |
2061 | |
2062 | ports= [IP_VS_FTP] IPVS ftp helper module |
2063 | Default is 21. |
2064 | Up to 8 (IP_VS_APP_MAX_PORTS) ports |
2065 | may be specified. |
2066 | Format: <port>,<port>.... |
2067 | |
2068 | print-fatal-signals= |
2069 | [KNL] debug: print fatal signals |
2070 | |
2071 | If enabled, warn about various signal handling |
2072 | related application anomalies: too many signals, |
2073 | too many POSIX.1 timers, fatal signals causing a |
2074 | coredump - etc. |
2075 | |
2076 | If you hit the warning due to signal overflow, |
2077 | you might want to try "ulimit -i unlimited". |
2078 | |
2079 | default: off. |
2080 | |
2081 | printk.time= Show timing data prefixed to each printk message line |
2082 | Format: <bool> (1/Y/y=enable, 0/N/n=disable) |
2083 | |
2084 | processor.max_cstate= [HW,ACPI] |
2085 | Limit processor to maximum C-state |
2086 | max_cstate=9 overrides any DMI blacklist limit. |
2087 | |
2088 | processor.nocst [HW,ACPI] |
2089 | Ignore the _CST method to determine C-states, |
2090 | instead using the legacy FADT method |
2091 | |
2092 | profile= [KNL] Enable kernel profiling via /proc/profile |
2093 | Format: [schedule,]<number> |
2094 | Param: "schedule" - profile schedule points. |
2095 | Param: <number> - step/bucket size as a power of 2 for |
2096 | statistical time based profiling. |
2097 | Param: "sleep" - profile D-state sleeping (millisecs). |
2098 | Requires CONFIG_SCHEDSTATS |
2099 | Param: "kvm" - profile VM exits. |
2100 | |
2101 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk |
2102 | before loading. |
2103 | See Documentation/blockdev/ramdisk.txt. |
2104 | |
2105 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to |
2106 | probe for; one of (bare|imps|exps|lifebook|any). |
2107 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports |
2108 | per second. |
2109 | psmouse.resetafter= [HW,MOUSE] |
2110 | Try to reset the device after so many bad packets |
2111 | (0 = never). |
2112 | psmouse.resolution= |
2113 | [HW,MOUSE] Set desired mouse resolution, in dpi. |
2114 | psmouse.smartscroll= |
2115 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. |
2116 | 0 = disabled, 1 = enabled (default). |
2117 | |
2118 | pt. [PARIDE] |
2119 | See Documentation/blockdev/paride.txt. |
2120 | |
2121 | pty.legacy_count= |
2122 | [KNL] Number of legacy pty's. Overwrites compiled-in |
2123 | default number. |
2124 | |
2125 | quiet [KNL] Disable most log messages |
2126 | |
2127 | r128= [HW,DRM] |
2128 | |
2129 | raid= [HW,RAID] |
2130 | See Documentation/md.txt. |
2131 | |
2132 | ramdisk_blocksize= [RAM] |
2133 | See Documentation/blockdev/ramdisk.txt. |
2134 | |
2135 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
2136 | See Documentation/blockdev/ramdisk.txt. |
2137 | |
2138 | rcupdate.blimit= [KNL,BOOT] |
2139 | Set maximum number of finished RCU callbacks to process |
2140 | in one batch. |
2141 | |
2142 | rcupdate.qhimark= [KNL,BOOT] |
2143 | Set threshold of queued |
2144 | RCU callbacks over which batch limiting is disabled. |
2145 | |
2146 | rcupdate.qlowmark= [KNL,BOOT] |
2147 | Set threshold of queued RCU callbacks below which |
2148 | batch limiting is re-enabled. |
2149 | |
2150 | rdinit= [KNL] |
2151 | Format: <full_path> |
2152 | Run specified binary instead of /init from the ramdisk, |
2153 | used for early userspace startup. See initrd. |
2154 | |
2155 | reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode |
2156 | Format: <reboot_mode>[,<reboot_mode2>[,...]] |
2157 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c |
2158 | |
2159 | relax_domain_level= |
2160 | [KNL, SMP] Set scheduler's default relax_domain_level. |
2161 | See Documentation/cgroups/cpusets.txt. |
2162 | |
2163 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area |
2164 | |
2165 | reservetop= [X86-32] |
2166 | Format: nn[KMG] |
2167 | Reserves a hole at the top of the kernel virtual |
2168 | address space. |
2169 | |
2170 | reservelow= [X86] |
2171 | Format: nn[K] |
2172 | Set the amount of memory to reserve for BIOS at |
2173 | the bottom of the address space. |
2174 | |
2175 | reset_devices [KNL] Force drivers to reset the underlying device |
2176 | during initialization. |
2177 | |
2178 | resume= [SWSUSP] |
2179 | Specify the partition device for software suspend |
2180 | |
2181 | resume_offset= [SWSUSP] |
2182 | Specify the offset from the beginning of the partition |
2183 | given by "resume=" at which the swap header is located, |
2184 | in <PAGE_SIZE> units (needed only for swap files). |
2185 | See Documentation/power/swsusp-and-swap-files.txt |
2186 | |
2187 | hibernate= [HIBERNATION] |
2188 | noresume Don't check if there's a hibernation image |
2189 | present during boot. |
2190 | nocompress Don't compress/decompress hibernation images. |
2191 | |
2192 | retain_initrd [RAM] Keep initrd memory after extraction |
2193 | |
2194 | rhash_entries= [KNL,NET] |
2195 | Set number of hash buckets for route cache |
2196 | |
2197 | riscom8= [HW,SERIAL] |
2198 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] |
2199 | |
2200 | ro [KNL] Mount root device read-only on boot |
2201 | |
2202 | root= [KNL] Root filesystem |
2203 | |
2204 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to |
2205 | mount the root filesystem |
2206 | |
2207 | rootflags= [KNL] Set root filesystem mount option string |
2208 | |
2209 | rootfstype= [KNL] Set root filesystem type |
2210 | |
2211 | rootwait [KNL] Wait (indefinitely) for root device to show up. |
2212 | Useful for devices that are detected asynchronously |
2213 | (e.g. USB and MMC devices). |
2214 | |
2215 | rw [KNL] Mount root device read-write on boot |
2216 | |
2217 | S [KNL] Run init in single mode |
2218 | |
2219 | sa1100ir [NET] |
2220 | See drivers/net/irda/sa1100_ir.c. |
2221 | |
2222 | sbni= [NET] Granch SBNI12 leased line adapter |
2223 | |
2224 | sched_debug [KNL] Enables verbose scheduler debug messages. |
2225 | |
2226 | security= [SECURITY] Choose a security module to enable at boot. |
2227 | If this boot parameter is not specified, only the first |
2228 | security module asking for security registration will be |
2229 | loaded. An invalid security module name will be treated |
2230 | as if no module has been chosen. |
2231 | |
2232 | selinux= [SELINUX] Disable or enable SELinux at boot time. |
2233 | Format: { "0" | "1" } |
2234 | See security/selinux/Kconfig help text. |
2235 | 0 -- disable. |
2236 | 1 -- enable. |
2237 | Default value is set via kernel config option. |
2238 | If enabled at boot time, /selinux/disable can be used |
2239 | later to disable prior to initial policy load. |
2240 | |
2241 | apparmor= [APPARMOR] Disable or enable AppArmor at boot time |
2242 | Format: { "0" | "1" } |
2243 | See security/apparmor/Kconfig help text |
2244 | 0 -- disable. |
2245 | 1 -- enable. |
2246 | Default value is set via kernel config option. |
2247 | |
2248 | serialnumber [BUGS=X86-32] |
2249 | |
2250 | shapers= [NET] |
2251 | Maximal number of shapers. |
2252 | |
2253 | show_msr= [x86] show boot-time MSR settings |
2254 | Format: { <integer> } |
2255 | Show boot-time (BIOS-initialized) MSR settings. |
2256 | The parameter means the number of CPUs to show, |
2257 | for example 1 means boot CPU only. |
2258 | |
2259 | simeth= [IA-64] |
2260 | simscsi= |
2261 | |
2262 | slram= [HW,MTD] |
2263 | |
2264 | slub_debug[=options[,slabs]] [MM, SLUB] |
2265 | Enabling slub_debug allows one to determine the |
2266 | culprit if slab objects become corrupted. Enabling |
2267 | slub_debug can create guard zones around objects and |
2268 | may poison objects when not in use. Also tracks the |
2269 | last alloc / free. For more information see |
2270 | Documentation/vm/slub.txt. |
2271 | |
2272 | slub_max_order= [MM, SLUB] |
2273 | Determines the maximum allowed order for slabs. |
2274 | A high setting may cause OOMs due to memory |
2275 | fragmentation. For more information see |
2276 | Documentation/vm/slub.txt. |
2277 | |
2278 | slub_min_objects= [MM, SLUB] |
2279 | The minimum number of objects per slab. SLUB will |
2280 | increase the slab order up to slub_max_order to |
2281 | generate a sufficiently large slab able to contain |
2282 | the number of objects indicated. The higher the number |
2283 | of objects the smaller the overhead of tracking slabs |
2284 | and the less frequently locks need to be acquired. |
2285 | For more information see Documentation/vm/slub.txt. |
2286 | |
2287 | slub_min_order= [MM, SLUB] |
2288 | Determines the mininum page order for slabs. Must be |
2289 | lower than slub_max_order. |
2290 | For more information see Documentation/vm/slub.txt. |
2291 | |
2292 | slub_nomerge [MM, SLUB] |
2293 | Disable merging of slabs with similar size. May be |
2294 | necessary if there is some reason to distinguish |
2295 | allocs to different slabs. Debug options disable |
2296 | merging on their own. |
2297 | For more information see Documentation/vm/slub.txt. |
2298 | |
2299 | smart2= [HW] |
2300 | Format: <io1>[,<io2>[,...,<io8>]] |
2301 | |
2302 | smp-alt-once [X86-32,SMP] On a hotplug CPU system, only |
2303 | attempt to substitute SMP alternatives once at boot. |
2304 | |
2305 | smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices |
2306 | smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port |
2307 | smsc-ircc2.ircc_sir= [HW] SIR base I/O port |
2308 | smsc-ircc2.ircc_fir= [HW] FIR base I/O port |
2309 | smsc-ircc2.ircc_irq= [HW] IRQ line |
2310 | smsc-ircc2.ircc_dma= [HW] DMA channel |
2311 | smsc-ircc2.ircc_transceiver= [HW] Transceiver type: |
2312 | 0: Toshiba Satellite 1800 (GP data pin select) |
2313 | 1: Fast pin select (default) |
2314 | 2: ATC IRMode |
2315 | |
2316 | softlockup_panic= |
2317 | [KNL] Should the soft-lockup detector generate panics. |
2318 | |
2319 | sonypi.*= [HW] Sony Programmable I/O Control Device driver |
2320 | See Documentation/sonypi.txt |
2321 | |
2322 | specialix= [HW,SERIAL] Specialix multi-serial port adapter |
2323 | See Documentation/serial/specialix.txt. |
2324 | |
2325 | spia_io_base= [HW,MTD] |
2326 | spia_fio_base= |
2327 | spia_pedr= |
2328 | spia_peddr= |
2329 | |
2330 | stacktrace [FTRACE] |
2331 | Enabled the stack tracer on boot up. |
2332 | |
2333 | sti= [PARISC,HW] |
2334 | Format: <num> |
2335 | Set the STI (builtin display/keyboard on the HP-PARISC |
2336 | machines) console (graphic card) which should be used |
2337 | as the initial boot-console. |
2338 | See also comment in drivers/video/console/sticore.c. |
2339 | |
2340 | sti_font= [HW] |
2341 | See comment in drivers/video/console/sticore.c. |
2342 | |
2343 | stifb= [HW] |
2344 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] |
2345 | |
2346 | sunrpc.min_resvport= |
2347 | sunrpc.max_resvport= |
2348 | [NFS,SUNRPC] |
2349 | SunRPC servers often require that client requests |
2350 | originate from a privileged port (i.e. a port in the |
2351 | range 0 < portnr < 1024). |
2352 | An administrator who wishes to reserve some of these |
2353 | ports for other uses may adjust the range that the |
2354 | kernel's sunrpc client considers to be privileged |
2355 | using these two parameters to set the minimum and |
2356 | maximum port values. |
2357 | |
2358 | sunrpc.pool_mode= |
2359 | [NFS] |
2360 | Control how the NFS server code allocates CPUs to |
2361 | service thread pools. Depending on how many NICs |
2362 | you have and where their interrupts are bound, this |
2363 | option will affect which CPUs will do NFS serving. |
2364 | Note: this parameter cannot be changed while the |
2365 | NFS server is running. |
2366 | |
2367 | auto the server chooses an appropriate mode |
2368 | automatically using heuristics |
2369 | global a single global pool contains all CPUs |
2370 | percpu one pool for each CPU |
2371 | pernode one pool for each NUMA node (equivalent |
2372 | to global on non-NUMA machines) |
2373 | |
2374 | sunrpc.tcp_slot_table_entries= |
2375 | sunrpc.udp_slot_table_entries= |
2376 | [NFS,SUNRPC] |
2377 | Sets the upper limit on the number of simultaneous |
2378 | RPC calls that can be sent from the client to a |
2379 | server. Increasing these values may allow you to |
2380 | improve throughput, but will also increase the |
2381 | amount of memory reserved for use by the client. |
2382 | |
2383 | swapaccount[=0|1] |
2384 | [KNL] Enable accounting of swap in memory resource |
2385 | controller if no parameter or 1 is given or disable |
2386 | it if 0 is given (See Documentation/cgroups/memory.txt) |
2387 | |
2388 | swiotlb= [IA-64] Number of I/O TLB slabs |
2389 | |
2390 | switches= [HW,M68k] |
2391 | |
2392 | sysfs.deprecated=0|1 [KNL] |
2393 | Enable/disable old style sysfs layout for old udev |
2394 | on older distributions. When this option is enabled |
2395 | very new udev will not work anymore. When this option |
2396 | is disabled (or CONFIG_SYSFS_DEPRECATED not compiled) |
2397 | in older udev will not work anymore. |
2398 | Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in |
2399 | the kernel configuration. |
2400 | |
2401 | sysrq_always_enabled |
2402 | [KNL] |
2403 | Ignore sysrq setting - this boot parameter will |
2404 | neutralize any effect of /proc/sys/kernel/sysrq. |
2405 | Useful for debugging. |
2406 | |
2407 | tdfx= [HW,DRM] |
2408 | |
2409 | test_suspend= [SUSPEND] |
2410 | Specify "mem" (for Suspend-to-RAM) or "standby" (for |
2411 | standby suspend) as the system sleep state to briefly |
2412 | enter during system startup. The system is woken from |
2413 | this state using a wakeup-capable RTC alarm. |
2414 | |
2415 | thash_entries= [KNL,NET] |
2416 | Set number of hash buckets for TCP connection |
2417 | |
2418 | thermal.act= [HW,ACPI] |
2419 | -1: disable all active trip points in all thermal zones |
2420 | <degrees C>: override all lowest active trip points |
2421 | |
2422 | thermal.crt= [HW,ACPI] |
2423 | -1: disable all critical trip points in all thermal zones |
2424 | <degrees C>: override all critical trip points |
2425 | |
2426 | thermal.nocrt= [HW,ACPI] |
2427 | Set to disable actions on ACPI thermal zone |
2428 | critical and hot trip points. |
2429 | |
2430 | thermal.off= [HW,ACPI] |
2431 | 1: disable ACPI thermal control |
2432 | |
2433 | thermal.psv= [HW,ACPI] |
2434 | -1: disable all passive trip points |
2435 | <degrees C>: override all passive trip points to this |
2436 | value |
2437 | |
2438 | thermal.tzp= [HW,ACPI] |
2439 | Specify global default ACPI thermal zone polling rate |
2440 | <deci-seconds>: poll all this frequency |
2441 | 0: no polling (default) |
2442 | |
2443 | topology= [S390] |
2444 | Format: {off | on} |
2445 | Specify if the kernel should make use of the cpu |
2446 | topology informations if the hardware supports these. |
2447 | The scheduler will make use of these informations and |
2448 | e.g. base its process migration decisions on it. |
2449 | Default is on. |
2450 | |
2451 | tp720= [HW,PS2] |
2452 | |
2453 | tpm_suspend_pcr=[HW,TPM] |
2454 | Format: integer pcr id |
2455 | Specify that at suspend time, the tpm driver |
2456 | should extend the specified pcr with zeros, |
2457 | as a workaround for some chips which fail to |
2458 | flush the last written pcr on TPM_SaveState. |
2459 | This will guarantee that all the other pcrs |
2460 | are saved. |
2461 | |
2462 | trace_buf_size=nn[KMG] |
2463 | [FTRACE] will set tracing buffer size. |
2464 | |
2465 | trace_event=[event-list] |
2466 | [FTRACE] Set and start specified trace events in order |
2467 | to facilitate early boot debugging. |
2468 | See also Documentation/trace/events.txt |
2469 | |
2470 | tsc= Disable clocksource-must-verify flag for TSC. |
2471 | Format: <string> |
2472 | [x86] reliable: mark tsc clocksource as reliable, this |
2473 | disables clocksource verification at runtime. |
2474 | Used to enable high-resolution timer mode on older |
2475 | hardware, and in virtualized environment. |
2476 | [x86] noirqtime: Do not use TSC to do irq accounting. |
2477 | Used to run time disable IRQ_TIME_ACCOUNTING on any |
2478 | platforms where RDTSC is slow and this accounting |
2479 | can add overhead. |
2480 | |
2481 | turbografx.map[2|3]= [HW,JOY] |
2482 | TurboGraFX parallel port interface |
2483 | Format: |
2484 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> |
2485 | See also Documentation/input/joystick-parport.txt |
2486 | |
2487 | uhash_entries= [KNL,NET] |
2488 | Set number of hash buckets for UDP/UDP-Lite connections |
2489 | |
2490 | uhci-hcd.ignore_oc= |
2491 | [USB] Ignore overcurrent events (default N). |
2492 | Some badly-designed motherboards generate lots of |
2493 | bogus events, for ports that aren't wired to |
2494 | anything. Set this parameter to avoid log spamming. |
2495 | Note that genuine overcurrent events won't be |
2496 | reported either. |
2497 | |
2498 | unknown_nmi_panic |
2499 | [X86] |
2500 | Set unknown_nmi_panic=1 early on boot. |
2501 | |
2502 | usbcore.autosuspend= |
2503 | [USB] The autosuspend time delay (in seconds) used |
2504 | for newly-detected USB devices (default 2). This |
2505 | is the time required before an idle device will be |
2506 | autosuspended. Devices for which the delay is set |
2507 | to a negative value won't be autosuspended at all. |
2508 | |
2509 | usbcore.usbfs_snoop= |
2510 | [USB] Set to log all usbfs traffic (default 0 = off). |
2511 | |
2512 | usbcore.blinkenlights= |
2513 | [USB] Set to cycle leds on hubs (default 0 = off). |
2514 | |
2515 | usbcore.old_scheme_first= |
2516 | [USB] Start with the old device initialization |
2517 | scheme (default 0 = off). |
2518 | |
2519 | usbcore.use_both_schemes= |
2520 | [USB] Try the other device initialization scheme |
2521 | if the first one fails (default 1 = enabled). |
2522 | |
2523 | usbcore.initial_descriptor_timeout= |
2524 | [USB] Specifies timeout for the initial 64-byte |
2525 | USB_REQ_GET_DESCRIPTOR request in milliseconds |
2526 | (default 5000 = 5.0 seconds). |
2527 | |
2528 | usbhid.mousepoll= |
2529 | [USBHID] The interval which mice are to be polled at. |
2530 | |
2531 | usb-storage.delay_use= |
2532 | [UMS] The delay in seconds before a new device is |
2533 | scanned for Logical Units (default 5). |
2534 | |
2535 | usb-storage.quirks= |
2536 | [UMS] A list of quirks entries to supplement or |
2537 | override the built-in unusual_devs list. List |
2538 | entries are separated by commas. Each entry has |
2539 | the form VID:PID:Flags where VID and PID are Vendor |
2540 | and Product ID values (4-digit hex numbers) and |
2541 | Flags is a set of characters, each corresponding |
2542 | to a common usb-storage quirk flag as follows: |
2543 | a = SANE_SENSE (collect more than 18 bytes |
2544 | of sense data); |
2545 | b = BAD_SENSE (don't collect more than 18 |
2546 | bytes of sense data); |
2547 | c = FIX_CAPACITY (decrease the reported |
2548 | device capacity by one sector); |
2549 | h = CAPACITY_HEURISTICS (decrease the |
2550 | reported device capacity by one |
2551 | sector if the number is odd); |
2552 | i = IGNORE_DEVICE (don't bind to this |
2553 | device); |
2554 | l = NOT_LOCKABLE (don't try to lock and |
2555 | unlock ejectable media); |
2556 | m = MAX_SECTORS_64 (don't transfer more |
2557 | than 64 sectors = 32 KB at a time); |
2558 | o = CAPACITY_OK (accept the capacity |
2559 | reported by the device); |
2560 | r = IGNORE_RESIDUE (the device reports |
2561 | bogus residue values); |
2562 | s = SINGLE_LUN (the device has only one |
2563 | Logical Unit); |
2564 | w = NO_WP_DETECT (don't test whether the |
2565 | medium is write-protected). |
2566 | Example: quirks=0419:aaf5:rl,0421:0433:rc |
2567 | |
2568 | userpte= |
2569 | [X86] Flags controlling user PTE allocations. |
2570 | |
2571 | nohigh = do not allocate PTE pages in |
2572 | HIGHMEM regardless of setting |
2573 | of CONFIG_HIGHPTE. |
2574 | |
2575 | vdso= [X86,SH] |
2576 | vdso=2: enable compat VDSO (default with COMPAT_VDSO) |
2577 | vdso=1: enable VDSO (default) |
2578 | vdso=0: disable VDSO mapping |
2579 | |
2580 | vdso32= [X86] |
2581 | vdso32=2: enable compat VDSO (default with COMPAT_VDSO) |
2582 | vdso32=1: enable 32-bit VDSO (default) |
2583 | vdso32=0: disable 32-bit VDSO mapping |
2584 | |
2585 | vector= [IA-64,SMP] |
2586 | vector=percpu: enable percpu vector domain |
2587 | |
2588 | video= [FB] Frame buffer configuration |
2589 | See Documentation/fb/modedb.txt. |
2590 | |
2591 | vga= [BOOT,X86-32] Select a particular video mode |
2592 | See Documentation/x86/boot.txt and |
2593 | Documentation/svga.txt. |
2594 | Use vga=ask for menu. |
2595 | This is actually a boot loader parameter; the value is |
2596 | passed to the kernel using a special protocol. |
2597 | |
2598 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact |
2599 | size of <nn>. This can be used to increase the |
2600 | minimum size (128MB on x86). It can also be used to |
2601 | decrease the size and leave more room for directly |
2602 | mapped kernel RAM. |
2603 | |
2604 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. |
2605 | Format: <command> |
2606 | |
2607 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. |
2608 | Format: <command> |
2609 | |
2610 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. |
2611 | Format: <command> |
2612 | |
2613 | vt.cur_default= [VT] Default cursor shape. |
2614 | Format: 0xCCBBAA, where AA, BB, and CC are the same as |
2615 | the parameters of the <Esc>[?A;B;Cc escape sequence; |
2616 | see VGA-softcursor.txt. Default: 2 = underline. |
2617 | |
2618 | vt.default_blu= [VT] |
2619 | Format: <blue0>,<blue1>,<blue2>,...,<blue15> |
2620 | Change the default blue palette of the console. |
2621 | This is a 16-member array composed of values |
2622 | ranging from 0-255. |
2623 | |
2624 | vt.default_grn= [VT] |
2625 | Format: <green0>,<green1>,<green2>,...,<green15> |
2626 | Change the default green palette of the console. |
2627 | This is a 16-member array composed of values |
2628 | ranging from 0-255. |
2629 | |
2630 | vt.default_red= [VT] |
2631 | Format: <red0>,<red1>,<red2>,...,<red15> |
2632 | Change the default red palette of the console. |
2633 | This is a 16-member array composed of values |
2634 | ranging from 0-255. |
2635 | |
2636 | vt.default_utf8= |
2637 | [VT] |
2638 | Format=<0|1> |
2639 | Set system-wide default UTF-8 mode for all tty's. |
2640 | Default is 1, i.e. UTF-8 mode is enabled for all |
2641 | newly opened terminals. |
2642 | |
2643 | vt.global_cursor_default= |
2644 | [VT] |
2645 | Format=<-1|0|1> |
2646 | Set system-wide default for whether a cursor |
2647 | is shown on new VTs. Default is -1, |
2648 | i.e. cursors will be created by default unless |
2649 | overridden by individual drivers. 0 will hide |
2650 | cursors, 1 will display them. |
2651 | |
2652 | watchdog timers [HW,WDT] For information on watchdog timers, |
2653 | see Documentation/watchdog/watchdog-parameters.txt |
2654 | or other driver-specific files in the |
2655 | Documentation/watchdog/ directory. |
2656 | |
2657 | x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of |
2658 | default x2apic cluster mode on platforms |
2659 | supporting x2apic. |
2660 | |
2661 | x86_mrst_timer= [X86-32,APBT] |
2662 | Choose timer option for x86 Moorestown MID platform. |
2663 | Two valid options are apbt timer only and lapic timer |
2664 | plus one apbt timer for broadcast timer. |
2665 | x86_mrst_timer=apbt_only | lapic_and_apbt |
2666 | |
2667 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. |
2668 | xd_geo= See header of drivers/block/xd.c. |
2669 | |
2670 | xen_emul_unplug= [HW,X86,XEN] |
2671 | Unplug Xen emulated devices |
2672 | Format: [unplug0,][unplug1] |
2673 | ide-disks -- unplug primary master IDE devices |
2674 | aux-ide-disks -- unplug non-primary-master IDE devices |
2675 | nics -- unplug network devices |
2676 | all -- unplug all emulated devices (NICs and IDE disks) |
2677 | unnecessary -- unplugging emulated devices is |
2678 | unnecessary even if the host did not respond to |
2679 | the unplug protocol |
2680 | never -- do not unplug even if version check succeeds |
2681 | |
2682 | xirc2ps_cs= [NET,PCMCIA] |
2683 | Format: |
2684 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] |
2685 | |
2686 | ______________________________________________________________________ |
2687 | |
2688 | TODO: |
2689 | |
2690 | Add more DRM drivers. |
2691 |
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Tags:
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