Commit | Line | Data |
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e53dd083 MCC |
1 | Kernel Parameters |
2 | ~~~~~~~~~~~~~~~~~ | |
1da177e4 LT |
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 | ||
a901ebb9 SR |
20 | This document may not be entirely up to date and comprehensive. The command |
21 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable | |
22 | module. Loadable modules, after being loaded into the running kernel, also | |
23 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these | |
24 | parameters may be changed at runtime by the command | |
25 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". | |
26 | ||
6585fa8a SR |
27 | The parameters listed below are only valid if certain kernel build options were |
28 | enabled and if respective hardware is present. The text in square brackets at | |
29 | the beginning of each description states the restrictions within which a | |
30 | parameter is applicable: | |
1da177e4 LT |
31 | |
32 | ACPI ACPI support is enabled. | |
c99c108a | 33 | AGP AGP (Accelerated Graphics Port) is enabled. |
1da177e4 LT |
34 | ALSA ALSA sound support is enabled. |
35 | APIC APIC support is enabled. | |
36 | APM Advanced Power Management support is enabled. | |
e7ba176b | 37 | AVR32 AVR32 architecture is enabled. |
1da177e4 | 38 | AX25 Appropriate AX.25 support is enabled. |
0ae53640 | 39 | BLACKFIN Blackfin architecture is enabled. |
a9913044 | 40 | DRM Direct Rendering Management support is enabled. |
1da177e4 LT |
41 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled |
42 | EFI EFI Partitioning (GPT) is enabled | |
43 | EIDE EIDE/ATAPI support is enabled. | |
44 | FB The frame buffer device is enabled. | |
45 | HW Appropriate hardware is enabled. | |
1da177e4 | 46 | IA-64 IA-64 architecture is enabled. |
6146f0d5 | 47 | IMA Integrity measurement architecture is enabled. |
1da177e4 | 48 | IOSCHED More than one I/O scheduler is enabled. |
41e2e8be | 49 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. |
1da177e4 LT |
50 | ISAPNP ISA PnP code is enabled. |
51 | ISDN Appropriate ISDN support is enabled. | |
52 | JOY Appropriate joystick support is enabled. | |
b9ce08c0 | 53 | KMEMTRACE kmemtrace is enabled. |
11ef697b | 54 | LIBATA Libata driver is enabled |
1da177e4 LT |
55 | LP Printer support is enabled. |
56 | LOOP Loopback device support is enabled. | |
57 | M68k M68k architecture is enabled. | |
58 | These options have more detailed description inside of | |
59 | Documentation/m68k/kernel-options.txt. | |
60 | MCA MCA bus support is enabled. | |
61 | MDA MDA console support is enabled. | |
62 | MOUSE Appropriate mouse support is enabled. | |
309e57df | 63 | MSI Message Signaled Interrupts (PCI). |
c8facbb6 | 64 | MTD MTD (Memory Technology Device) support is enabled. |
1da177e4 LT |
65 | NET Appropriate network support is enabled. |
66 | NUMA NUMA support is enabled. | |
734efb46 | 67 | GENERIC_TIME The generic timeofday code is enabled. |
1da177e4 LT |
68 | NFS Appropriate NFS support is enabled. |
69 | OSS OSS sound support is enabled. | |
c8facbb6 RD |
70 | PV_OPS A paravirtualized kernel is enabled. |
71 | PARIDE The ParIDE (parallel port IDE) subsystem is enabled. | |
1da177e4 LT |
72 | PARISC The PA-RISC architecture is enabled. |
73 | PCI PCI bus support is enabled. | |
7f785763 | 74 | PCIE PCI Express support is enabled. |
1da177e4 LT |
75 | PCMCIA The PCMCIA subsystem is enabled. |
76 | PNP Plug & Play support is enabled. | |
77 | PPC PowerPC architecture is enabled. | |
78 | PPT Parallel port support is enabled. | |
79 | PS2 Appropriate PS/2 support is enabled. | |
80 | RAM RAM disk support is enabled. | |
20510f2f | 81 | ROOTPLUG The example Root Plug LSM is enabled. |
1da177e4 LT |
82 | S390 S390 architecture is enabled. |
83 | SCSI Appropriate SCSI support is enabled. | |
84 | A lot of drivers has their options described inside of | |
85 | Documentation/scsi/. | |
20510f2f | 86 | SECURITY Different security models are enabled. |
1da177e4 LT |
87 | SELINUX SELinux support is enabled. |
88 | SERIAL Serial support is enabled. | |
e523d93c | 89 | SH SuperH architecture is enabled. |
1da177e4 LT |
90 | SMP The kernel is an SMP kernel. |
91 | SPARC Sparc architecture is enabled. | |
77437fd4 DB |
92 | SWSUSP Software suspend (hibernation) is enabled. |
93 | SUSPEND System suspend states are enabled. | |
f38f1d2a | 94 | FTRACE Function tracing enabled. |
1da177e4 | 95 | TS Appropriate touchscreen support is enabled. |
d4f373e5 | 96 | UMS USB Mass Storage support is enabled. |
1da177e4 LT |
97 | USB USB support is enabled. |
98 | USBHID USB Human Interface Device support is enabled. | |
99 | V4L Video For Linux support is enabled. | |
100 | VGA The VGA console has been enabled. | |
101 | VT Virtual terminal support is enabled. | |
102 | WDT Watchdog support is enabled. | |
103 | XT IBM PC/XT MFM hard disk support is enabled. | |
cd4f0ef7 | 104 | X86-32 X86-32, aka i386 architecture is enabled. |
1da177e4 LT |
105 | X86-64 X86-64 architecture is enabled. |
106 | More X86-64 boot options can be found in | |
71cced6e | 107 | Documentation/x86/x86_64/boot-options.txt . |
c0115606 | 108 | X86 Either 32bit or 64bit x86 (same as X86-32+X86-64) |
1da177e4 LT |
109 | |
110 | In addition, the following text indicates that the option: | |
111 | ||
112 | BUGS= Relates to possible processor bugs on the said processor. | |
113 | KNL Is a kernel start-up parameter. | |
114 | BOOT Is a boot loader parameter. | |
115 | ||
116 | Parameters denoted with BOOT are actually interpreted by the boot | |
117 | loader, and have no meaning to the kernel directly. | |
118 | Do not modify the syntax of boot loader parameters without extreme | |
954a8b81 | 119 | need or coordination with <Documentation/x86/boot.txt>. |
1da177e4 | 120 | |
5558870b | 121 | There are also arch-specific kernel-parameters not documented here. |
71cced6e | 122 | See for example <Documentation/x86/x86_64/boot-options.txt>. |
5558870b | 123 | |
1da177e4 LT |
124 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that |
125 | a trailing = on the name of any parameter states that that parameter will | |
126 | be entered as an environment variable, whereas its absence indicates that | |
127 | it will appear as a kernel argument readable via /proc/cmdline by programs | |
128 | running once the system is up. | |
129 | ||
9c4751fd | 130 | The number of kernel parameters is not limited, but the length of the |
131 | complete command line (parameters including spaces etc.) is limited to | |
132 | a fixed number of characters. This limit depends on the architecture | |
133 | and is between 256 and 4096 characters. It is defined in the file | |
134 | ./include/asm/setup.h as COMMAND_LINE_SIZE. | |
135 | ||
136 | ||
03d926f8 BW |
137 | acpi= [HW,ACPI,X86-64,i386] |
138 | Advanced Configuration and Power Interface | |
af23f573 | 139 | Format: { force | off | ht | strict | noirq | rsdt } |
1da177e4 LT |
140 | force -- enable ACPI if default was off |
141 | off -- disable ACPI if default was on | |
142 | noirq -- do not use ACPI for IRQ routing | |
143 | ht -- run only enough ACPI to enable Hyper Threading | |
a9913044 | 144 | strict -- Be less tolerant of platforms that are not |
1da177e4 | 145 | strictly ACPI specification compliant. |
237889bf | 146 | rsdt -- prefer RSDT over (default) XSDT |
1da177e4 | 147 | |
53471121 | 148 | See also Documentation/power/pm.txt, pci=noacpi |
1da177e4 | 149 | |
a1fdcc0d LB |
150 | acpi_apic_instance= [ACPI, IOAPIC] |
151 | Format: <int> | |
152 | 2: use 2nd APIC table, if available | |
153 | 1,0: use 1st APIC table | |
4e381a4f | 154 | default: 0 |
a1fdcc0d | 155 | |
c3d6de69 TR |
156 | acpi_backlight= [HW,ACPI] |
157 | acpi_backlight=vendor | |
158 | acpi_backlight=video | |
159 | If set to vendor, prefer vendor specific driver | |
160 | (e.g. thinkpad_acpi, sony_acpi, etc.) instead | |
161 | of the ACPI video.ko driver. | |
162 | ||
a0d84a92 BH |
163 | acpi.debug_layer= [HW,ACPI,ACPI_DEBUG] |
164 | acpi.debug_level= [HW,ACPI,ACPI_DEBUG] | |
1da177e4 | 165 | Format: <int> |
a0d84a92 BH |
166 | CONFIG_ACPI_DEBUG must be enabled to produce any ACPI |
167 | debug output. Bits in debug_layer correspond to a | |
168 | _COMPONENT in an ACPI source file, e.g., | |
169 | #define _COMPONENT ACPI_PCI_COMPONENT | |
170 | Bits in debug_level correspond to a level in | |
171 | ACPI_DEBUG_PRINT statements, e.g., | |
172 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, ... | |
e76f4276 BH |
173 | The debug_level mask defaults to "info". See |
174 | Documentation/acpi/debug.txt for more information about | |
175 | debug layers and levels. | |
a0d84a92 | 176 | |
e76f4276 BH |
177 | Enable processor driver info messages: |
178 | acpi.debug_layer=0x20000000 | |
179 | Enable PCI/PCI interrupt routing info messages: | |
180 | acpi.debug_layer=0x400000 | |
a0d84a92 BH |
181 | Enable AML "Debug" output, i.e., stores to the Debug |
182 | object while interpreting AML: | |
183 | acpi.debug_layer=0xffffffff acpi.debug_level=0x2 | |
a0d84a92 BH |
184 | Enable all messages related to ACPI hardware: |
185 | acpi.debug_layer=0x2 acpi.debug_level=0xffffffff | |
186 | ||
187 | Some values produce so much output that the system is | |
188 | unusable. The "log_buf_len" parameter may be useful | |
189 | if you need to capture more output. | |
f989106c | 190 | |
0cb55ad2 RD |
191 | acpi_display_output= [HW,ACPI] |
192 | acpi_display_output=vendor | |
193 | acpi_display_output=video | |
194 | See above. | |
195 | ||
196 | acpi_irq_balance [HW,ACPI] | |
197 | ACPI will balance active IRQs | |
198 | default in APIC mode | |
199 | ||
200 | acpi_irq_nobalance [HW,ACPI] | |
201 | ACPI will not move active IRQs (default) | |
202 | default in PIC mode | |
203 | ||
204 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA | |
205 | Format: <irq>,<irq>... | |
206 | ||
207 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for | |
208 | use by PCI | |
209 | Format: <irq>,<irq>... | |
210 | ||
211 | acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT | |
212 | ||
213 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS | |
214 | Format: To spoof as Windows 98: ="Microsoft Windows" | |
215 | ||
216 | acpi_osi= [HW,ACPI] Modify list of supported OS interface strings | |
217 | acpi_osi="string1" # add string1 -- only one string | |
218 | acpi_osi="!string2" # remove built-in string2 | |
219 | acpi_osi= # disable all strings | |
220 | ||
221 | acpi_pm_good [X86-32,X86-64] | |
222 | Override the pmtimer bug detection: force the kernel | |
223 | to assume that this machine's pmtimer latches its value | |
224 | and always returns good values. | |
225 | ||
f5adfaa3 ZY |
226 | acpi.power_nocheck= [HW,ACPI] |
227 | Format: 1/0 enable/disable the check of power state. | |
228 | On some bogus BIOS the _PSC object/_STA object of | |
229 | power resource can't return the correct device power | |
230 | state. In such case it is unneccessary to check its | |
231 | power state again in power transition. | |
232 | 1 : disable the power state check | |
233 | ||
7e90560c LT |
234 | acpi_enforce_resources= [ACPI] |
235 | { strict | lax | no } | |
236 | Check for resource conflicts between native drivers | |
237 | and ACPI OperationRegions (SystemIO and SystemMemory | |
238 | only). IO ports and memory declared in ACPI might be | |
239 | used by the ACPI subsystem in arbitrary AML code and | |
240 | can interfere with legacy drivers. | |
241 | strict (default): access to resources claimed by ACPI | |
242 | is denied; legacy drivers trying to access reserved | |
243 | resources will fail to bind to device using them. | |
244 | lax: access to resources claimed by ACPI is allowed; | |
245 | legacy drivers trying to access reserved resources | |
246 | will bind successfully but a warning message is logged. | |
247 | no: ACPI OperationRegions are not marked as reserved, | |
248 | no further checks are performed. | |
249 | ||
1da177e4 LT |
250 | ad1848= [HW,OSS] |
251 | Format: <io>,<irq>,<dma>,<dma2>,<type> | |
252 | ||
1da177e4 LT |
253 | advansys= [HW,SCSI] |
254 | See header of drivers/scsi/advansys.c. | |
255 | ||
256 | advwdt= [HW,WDT] Advantech WDT | |
257 | Format: <iostart>,<iostop> | |
258 | ||
259 | aedsp16= [HW,OSS] Audio Excel DSP 16 | |
260 | Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq> | |
261 | See also header of sound/oss/aedsp16.c. | |
a9913044 | 262 | |
0cb55ad2 RD |
263 | agp= [AGP] |
264 | { off | try_unsupported } | |
265 | off: disable AGP support | |
266 | try_unsupported: try to drive unsupported chipsets | |
267 | (may crash computer or cause data corruption) | |
268 | ||
1da177e4 LT |
269 | aha152x= [HW,SCSI] |
270 | See Documentation/scsi/aha152x.txt. | |
271 | ||
272 | aha1542= [HW,SCSI] | |
273 | Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]] | |
274 | ||
275 | aic7xxx= [HW,SCSI] | |
276 | See Documentation/scsi/aic7xxx.txt. | |
277 | ||
278 | aic79xx= [HW,SCSI] | |
279 | See Documentation/scsi/aic79xx.txt. | |
280 | ||
54b4cbd2 JR |
281 | amd_iommu= [HW,X86-84] |
282 | Pass parameters to the AMD IOMMU driver in the system. | |
283 | Possible values are: | |
54b4cbd2 JR |
284 | isolate - enable device isolation (each device, as far |
285 | as possible, will get its own protection | |
3ce1f93c | 286 | domain) [default] |
e5e1f606 JR |
287 | share - put every device behind one IOMMU into the |
288 | same protection domain | |
afa9fdc2 FT |
289 | fullflush - enable flushing of IO/TLB entries when |
290 | they are unmapped. Otherwise they are | |
291 | flushed before they will be reused, which | |
292 | is a lot of faster | |
293 | ||
54b4cbd2 JR |
294 | amd_iommu_size= [HW,X86-64] |
295 | Define the size of the aperture for the AMD IOMMU | |
296 | driver. Possible values are: | |
297 | '32M', '64M' (default), '128M', '256M', '512M', '1G' | |
298 | ||
1da177e4 LT |
299 | amijoy.map= [HW,JOY] Amiga joystick support |
300 | Map of devices attached to JOY0DAT and JOY1DAT | |
301 | Format: <a>,<b> | |
302 | See also Documentation/kernel/input/joystick.txt | |
303 | ||
304 | analog.map= [HW,JOY] Analog joystick and gamepad support | |
305 | Specifies type or capabilities of an analog joystick | |
306 | connected to one of 16 gameports | |
307 | Format: <type1>,<type2>,..<type16> | |
308 | ||
a9913044 RD |
309 | apc= [HW,SPARC] |
310 | Power management functions (SPARCstation-4/5 + deriv.) | |
1da177e4 LT |
311 | Format: noidle |
312 | Disable APC CPU standby support. SPARCstation-Fox does | |
313 | not play well with APC CPU idle - disable it if you have | |
314 | APC and your system crashes randomly. | |
315 | ||
c8facbb6 RD |
316 | apic= [APIC,i386] Advanced Programmable Interrupt Controller |
317 | Change the output verbosity whilst booting | |
1da177e4 LT |
318 | Format: { quiet (default) | verbose | debug } |
319 | Change the amount of debugging information output | |
320 | when initialising the APIC and IO-APIC components. | |
a9913044 | 321 | |
1da177e4 | 322 | apm= [APM] Advanced Power Management |
71f77055 | 323 | See header of arch/x86/kernel/apm_32.c. |
1da177e4 | 324 | |
1da177e4 LT |
325 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards |
326 | Format: <io>,<irq>,<nodeID> | |
327 | ||
328 | ataflop= [HW,M68k] | |
329 | ||
330 | atarimouse= [HW,MOUSE] Atari Mouse | |
331 | ||
332 | atascsi= [HW,SCSI] Atari SCSI | |
333 | ||
334 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, | |
335 | EzKey and similar keyboards | |
336 | ||
337 | atkbd.reset= [HW] Reset keyboard during initialization | |
338 | ||
a9913044 RD |
339 | atkbd.set= [HW] Select keyboard code set |
340 | Format: <int> (2 = AT (default), 3 = PS/2) | |
1da177e4 LT |
341 | |
342 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar | |
343 | keyboards | |
344 | ||
345 | atkbd.softraw= [HW] Choose between synthetic and real raw mode | |
346 | Format: <bool> (0 = real, 1 = synthetic (default)) | |
a9913044 RD |
347 | |
348 | atkbd.softrepeat= [HW] | |
349 | Use software keyboard repeat | |
1da177e4 LT |
350 | |
351 | autotest [IA64] | |
352 | ||
1da177e4 LT |
353 | baycom_epp= [HW,AX25] |
354 | Format: <io>,<mode> | |
a9913044 | 355 | |
1da177e4 LT |
356 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem |
357 | Format: <io>,<mode> | |
358 | See header of drivers/net/hamradio/baycom_par.c. | |
359 | ||
a9913044 RD |
360 | baycom_ser_fdx= [HW,AX25] |
361 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) | |
1da177e4 LT |
362 | Format: <io>,<irq>,<mode>[,<baud>] |
363 | See header of drivers/net/hamradio/baycom_ser_fdx.c. | |
364 | ||
a9913044 RD |
365 | baycom_ser_hdx= [HW,AX25] |
366 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) | |
1da177e4 LT |
367 | Format: <io>,<irq>,<mode> |
368 | See header of drivers/net/hamradio/baycom_ser_hdx.c. | |
369 | ||
bfe8df3d RD |
370 | boot_delay= Milliseconds to delay each printk during boot. |
371 | Values larger than 10 seconds (10000) are changed to | |
372 | no delay (0). | |
373 | Format: integer | |
374 | ||
35fc908d AH |
375 | bootmem_debug [KNL] Enable bootmem allocator debug messages. |
376 | ||
1da177e4 | 377 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) |
a9913044 RD |
378 | bttv.radio= Most important insmod options are available as |
379 | kernel args too. | |
1da177e4 LT |
380 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options |
381 | bttv.tuner= and Documentation/video4linux/bttv/CARDLIST | |
382 | ||
383 | BusLogic= [HW,SCSI] | |
384 | See drivers/scsi/BusLogic.c, comment before function | |
385 | BusLogic_ParseDriverOptions(). | |
386 | ||
387 | c101= [NET] Moxa C101 synchronous serial card | |
388 | ||
cd4f0ef7 | 389 | cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection. |
1da177e4 LT |
390 | Sometimes CPU hardware bugs make them report the cache |
391 | size incorrectly. The kernel will attempt work arounds | |
392 | to fix known problems, but for some CPUs it is not | |
393 | possible to determine what the correct size should be. | |
394 | This option provides an override for these situations. | |
395 | ||
20510f2f JM |
396 | capability.disable= |
397 | [SECURITY] Disable capabilities. This would normally | |
398 | be used only if an alternative security model is to be | |
399 | configured. Potentially dangerous and should only be | |
400 | used if you are entirely sure of the consequences. | |
401 | ||
14ff56bb SO |
402 | ccw_timeout_log [S390] |
403 | See Documentation/s390/CommonIO for details. | |
1da177e4 | 404 | |
8bab8dde PM |
405 | cgroup_disable= [KNL] Disable a particular controller |
406 | Format: {name of the controller(s) to disable} | |
407 | {Currently supported controllers - "memory"} | |
408 | ||
1da177e4 LT |
409 | checkreqprot [SELINUX] Set initial checkreqprot flag value. |
410 | Format: { "0" | "1" } | |
411 | See security/selinux/Kconfig help text. | |
a9913044 RD |
412 | 0 -- check protection applied by kernel (includes |
413 | any implied execute protection). | |
1da177e4 LT |
414 | 1 -- check protection requested by application. |
415 | Default value is set via a kernel config option. | |
a9913044 RD |
416 | Value can be changed at runtime via |
417 | /selinux/checkreqprot. | |
418 | ||
661ca0da SO |
419 | cio_ignore= [S390] |
420 | See Documentation/s390/CommonIO for details. | |
421 | ||
cd4f0ef7 | 422 | clock= [BUGS=X86-32, HW] gettimeofday clocksource override. |
734efb46 | 423 | [Deprecated] |
3f6dee9b | 424 | Forces specified clocksource (if available) to be used |
734efb46 | 425 | when calculating gettimeofday(). If specified |
3f6dee9b | 426 | clocksource is not available, it defaults to PIT. |
1da177e4 LT |
427 | Format: { pit | tsc | cyclone | pmtmr } |
428 | ||
3d6ac984 RD |
429 | clocksource= [GENERIC_TIME] Override the default clocksource |
430 | Format: <string> | |
431 | Override the default clocksource and use the clocksource | |
432 | with the name specified. | |
433 | Some clocksource names to choose from, depending on | |
434 | the platform: | |
435 | [all] jiffies (this is the base, fallback clocksource) | |
436 | [ACPI] acpi_pm | |
437 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, | |
438 | pxa_timer,timer3,32k_counter,timer0_1 | |
439 | [AVR32] avr32 | |
cd4f0ef7 | 440 | [X86-32] pit,hpet,tsc,vmi-timer; |
3d6ac984 RD |
441 | scx200_hrt on Geode; cyclone on IBM x440 |
442 | [MIPS] MIPS | |
443 | [PARISC] cr16 | |
444 | [S390] tod | |
445 | [SH] SuperH | |
446 | [SPARC64] tick | |
447 | [X86-64] hpet,tsc | |
448 | ||
ac72e788 AK |
449 | clearcpuid=BITNUM [X86] |
450 | Disable CPUID feature X for the kernel. See | |
07983f0e RD |
451 | arch/x86/include/asm/cpufeature.h for the valid bit |
452 | numbers. Note the Linux specific bits are not necessarily | |
ac72e788 AK |
453 | stable over kernel options, but the vendor specific |
454 | ones should be. | |
455 | Also note that user programs calling CPUID directly | |
456 | or using the feature without checking anything | |
457 | will still see it. This just prevents it from | |
458 | being used by the kernel or shown in /proc/cpuinfo. | |
459 | Also note the kernel might malfunction if you disable | |
460 | some critical bits. | |
461 | ||
a25bd949 AV |
462 | code_bytes [IA32/X86_64] How many bytes of object code to print |
463 | in an oops report. | |
86c41837 CE |
464 | Range: 0 - 8192 |
465 | Default: 64 | |
466 | ||
1da177e4 | 467 | com20020= [HW,NET] ARCnet - COM20020 chipset |
a9913044 RD |
468 | Format: |
469 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] | |
1da177e4 LT |
470 | |
471 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) | |
472 | Format: <io>[,<irq>] | |
473 | ||
a9913044 RD |
474 | com90xx= [HW,NET] |
475 | ARCnet - COM90xx chipset (memory-mapped buffers) | |
1da177e4 LT |
476 | Format: <io>[,<irq>[,<memstart>]] |
477 | ||
478 | condev= [HW,S390] console device | |
479 | conmode= | |
a9913044 | 480 | |
1da177e4 LT |
481 | console= [KNL] Output console device and options. |
482 | ||
483 | tty<n> Use the virtual console device <n>. | |
484 | ||
485 | ttyS<n>[,options] | |
f1a1c2dc | 486 | ttyUSB0[,options] |
1da177e4 | 487 | Use the specified serial port. The options are of |
f1a1c2dc RD |
488 | the form "bbbbpnf", where "bbbb" is the baud rate, |
489 | "p" is parity ("n", "o", or "e"), "n" is number of | |
490 | bits, and "f" is flow control ("r" for RTS or | |
491 | omit it). Default is "9600n8". | |
492 | ||
493 | See Documentation/serial-console.txt for more | |
494 | information. See | |
495 | Documentation/networking/netconsole.txt for an | |
496 | alternative. | |
1da177e4 | 497 | |
18a8bd94 YL |
498 | uart[8250],io,<addr>[,options] |
499 | uart[8250],mmio,<addr>[,options] | |
1da177e4 LT |
500 | Start an early, polled-mode console on the 8250/16550 |
501 | UART at the specified I/O port or MMIO address, | |
502 | switching to the matching ttyS device later. The | |
503 | options are the same as for ttyS, above. | |
504 | ||
f7511d5f ST |
505 | If the device connected to the port is not a TTY but a braille |
506 | device, prepend "brl," before the device type, for instance | |
507 | console=brl,ttyS0 | |
508 | For now, only VisioBraille is supported. | |
509 | ||
4cb0e11b HK |
510 | coredump_filter= |
511 | [KNL] Change the default value for | |
512 | /proc/<pid>/coredump_filter. | |
513 | See also Documentation/filesystems/proc.txt. | |
514 | ||
1da177e4 | 515 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver |
a9913044 RD |
516 | Format: |
517 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] | |
1da177e4 | 518 | |
dc009d92 EB |
519 | crashkernel=nn[KMG]@ss[KMG] |
520 | [KNL] Reserve a chunk of physical memory to | |
521 | hold a kernel to switch to with kexec on panic. | |
522 | ||
fb391599 BW |
523 | crashkernel=range1:size1[,range2:size2,...][@offset] |
524 | [KNL] Same as above, but depends on the memory | |
525 | in the running system. The syntax of range is | |
526 | start-[end] where start and end are both | |
527 | a memory unit (amount[KMG]). See also | |
528 | Documentation/kdump/kdump.txt for a example. | |
529 | ||
1da177e4 LT |
530 | cs89x0_dma= [HW,NET] |
531 | Format: <dma> | |
532 | ||
533 | cs89x0_media= [HW,NET] | |
534 | Format: { rj45 | aui | bnc } | |
a9913044 | 535 | |
a9913044 | 536 | dasd= [HW,NET] |
1da177e4 LT |
537 | See header of drivers/s390/block/dasd_devmap.c. |
538 | ||
539 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port | |
540 | (one device per port) | |
541 | Format: <port#>,<type> | |
542 | See also Documentation/input/joystick-parport.txt | |
543 | ||
544 | debug [KNL] Enable kernel debugging (events log level). | |
545 | ||
cae2ed9a IM |
546 | debug_locks_verbose= |
547 | [KNL] verbose self-tests | |
548 | Format=<0|1> | |
549 | Print debugging info while doing the locking API | |
550 | self-tests. | |
551 | We default to 0 (no extra messages), setting it to | |
552 | 1 will print _a lot_ more information - normally | |
553 | only useful to kernel developers. | |
554 | ||
3ac7fe5a TG |
555 | debug_objects [KNL] Enable object debugging |
556 | ||
3e8ebb5c KM |
557 | no_debug_objects |
558 | [KNL] Disable object debugging | |
559 | ||
d3af01f1 TG |
560 | debugpat [X86] Enable PAT debugging |
561 | ||
2d27a966 | 562 | decnet.addr= [HW,NET] |
1da177e4 LT |
563 | Format: <area>[,<node>] |
564 | See also Documentation/networking/decnet.txt. | |
565 | ||
0cb55ad2 RD |
566 | default_hugepagesz= |
567 | [same as hugepagesz=] The size of the default | |
568 | HugeTLB page size. This is the size represented by | |
569 | the legacy /proc/ hugepages APIs, used for SHM, and | |
570 | default size when mounting hugetlbfs filesystems. | |
571 | Defaults to the default architecture's huge page size | |
572 | if not specified. | |
55ff9780 | 573 | |
1da177e4 LT |
574 | dhash_entries= [KNL] |
575 | Set number of hash buckets for dentry cache. | |
a9913044 | 576 | |
1da177e4 LT |
577 | digi= [HW,SERIAL] |
578 | IO parameters + enable/disable command. | |
579 | ||
580 | digiepca= [HW,SERIAL] | |
581 | See drivers/char/README.epca and | |
31c00fc1 | 582 | Documentation/serial/digiepca.txt. |
1da177e4 | 583 | |
95ffa243 | 584 | disable_mtrr_cleanup [X86] |
95ffa243 YL |
585 | The kernel tries to adjust MTRR layout from continuous |
586 | to discrete, to make X server driver able to add WB | |
0cb55ad2 | 587 | entry later. This parameter disables that. |
95ffa243 | 588 | |
093af8d7 | 589 | disable_mtrr_trim [X86, Intel and AMD only] |
99fc8d42 JB |
590 | By default the kernel will trim any uncacheable |
591 | memory out of your available memory pool based on | |
592 | MTRR settings. This parameter disables that behavior, | |
593 | possibly causing your machine to run very slowly. | |
594 | ||
0cb55ad2 RD |
595 | disable_timer_pin_1 [i386,x86-64] |
596 | Disable PIN 1 of APIC timer | |
597 | Can be useful to work around chipset bugs. | |
598 | ||
1da177e4 LT |
599 | dmasound= [HW,OSS] Sound subsystem buffers |
600 | ||
0cb55ad2 RD |
601 | dma_debug=off If the kernel is compiled with DMA_API_DEBUG support, |
602 | this option disables the debugging code at boot. | |
603 | ||
604 | dma_debug_entries=<number> | |
605 | This option allows to tune the number of preallocated | |
606 | entries for DMA-API debugging code. One entry is | |
607 | required per DMA-API allocation. Use this if the | |
608 | DMA-API debugging code disables itself because the | |
609 | architectural default is too low. | |
610 | ||
1da177e4 LT |
611 | dscc4.setup= [NET] |
612 | ||
613 | dtc3181e= [HW,SCSI] | |
614 | ||
0cb55ad2 RD |
615 | dynamic_printk Enables pr_debug()/dev_dbg() calls if |
616 | CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. | |
617 | These can also be switched on/off via | |
618 | <debugfs>/dynamic_printk/modules | |
619 | ||
620 | earlycon= [KNL] Output early console device and options. | |
621 | uart[8250],io,<addr>[,options] | |
622 | uart[8250],mmio,<addr>[,options] | |
623 | Start an early, polled-mode console on the 8250/16550 | |
624 | UART at the specified I/O port or MMIO address. | |
625 | The options are the same as for ttyS, above. | |
626 | ||
0ae53640 | 627 | earlyprintk= [X86-32,X86-64,SH,BLACKFIN] |
1da177e4 LT |
628 | earlyprintk=vga |
629 | earlyprintk=serial[,ttySn[,baudrate]] | |
5c05917e | 630 | earlyprintk=dbgp |
1da177e4 | 631 | |
a9913044 | 632 | Append ",keep" to not disable it when the real console |
1da177e4 LT |
633 | takes over. |
634 | ||
5c05917e | 635 | Only vga or serial or usb debug port at a time. |
1da177e4 LT |
636 | |
637 | Currently only ttyS0 and ttyS1 are supported. | |
638 | ||
639 | Interaction with the standard serial driver is not | |
640 | very good. | |
641 | ||
642 | The VGA output is eventually overwritten by the real | |
643 | console. | |
644 | ||
645 | eata= [HW,SCSI] | |
646 | ||
1da177e4 | 647 | edd= [EDD] |
8c4dd606 | 648 | Format: {"off" | "on" | "skip[mbr]"} |
1da177e4 | 649 | |
1da177e4 LT |
650 | eisa_irq_edge= [PARISC,HW] |
651 | See header of drivers/parisc/eisa.c. | |
652 | ||
cd4f0ef7 | 653 | elanfreq= [X86-32] |
1da177e4 | 654 | See comment before function elanfreq_setup() in |
71f77055 | 655 | arch/x86/kernel/cpu/cpufreq/elanfreq.c. |
1da177e4 LT |
656 | |
657 | elevator= [IOSCHED] | |
16ab3adf | 658 | Format: {"anticipatory" | "cfq" | "deadline" | "noop"} |
a9913044 RD |
659 | See Documentation/block/as-iosched.txt and |
660 | Documentation/block/deadline-iosched.txt for details. | |
661 | ||
e515a0d6 | 662 | elfcorehdr= [IA64,PPC,SH,X86-32,X86_64] |
a9913044 | 663 | Specifies physical address of start of kernel core |
aac04b32 VG |
664 | image elf header. Generally kexec loader will |
665 | pass this option to capture kernel. | |
666 | See Documentation/kdump/kdump.txt for details. | |
1da177e4 | 667 | |
0cb55ad2 RD |
668 | enable_mtrr_cleanup [X86] |
669 | The kernel tries to adjust MTRR layout from continuous | |
670 | to discrete, to make X server driver able to add WB | |
671 | entry later. This parameter enables that. | |
672 | ||
673 | enable_timer_pin_1 [i386,x86-64] | |
674 | Enable PIN 1 of APIC timer | |
675 | Can be useful to work around chipset bugs | |
676 | (in particular on some ATI chipsets). | |
677 | The kernel tries to set a reasonable default. | |
678 | ||
1da177e4 LT |
679 | enforcing [SELINUX] Set initial enforcing status. |
680 | Format: {"0" | "1"} | |
681 | See security/selinux/Kconfig help text. | |
682 | 0 -- permissive (log only, no denials). | |
683 | 1 -- enforcing (deny and log). | |
684 | Default value is 0. | |
685 | Value can be changed at runtime via /selinux/enforce. | |
686 | ||
1da177e4 LT |
687 | ether= [HW,NET] Ethernet cards parameters |
688 | This option is obsoleted by the "netdev=" option, which | |
689 | has equivalent usage. See its documentation for details. | |
690 | ||
691 | eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog. | |
692 | Format: <io>[,<irq>] | |
693 | ||
de1ba09b AM |
694 | failslab= |
695 | fail_page_alloc= | |
696 | fail_make_request=[KNL] | |
697 | General fault injection mechanism. | |
698 | Format: <interval>,<probability>,<space>,<times> | |
699 | See also /Documentation/fault-injection/. | |
700 | ||
1da177e4 LT |
701 | fd_mcs= [HW,SCSI] |
702 | See header of drivers/scsi/fd_mcs.c. | |
703 | ||
704 | fdomain= [HW,SCSI] | |
705 | See header of drivers/scsi/fdomain.c. | |
706 | ||
707 | floppy= [HW] | |
31c00fc1 | 708 | See Documentation/blockdev/floppy.txt. |
1da177e4 | 709 | |
f13ae30e AC |
710 | force_pal_cache_flush |
711 | [IA-64] Avoid check_sal_cache_flush which may hang on | |
712 | buggy SAL_CACHE_FLUSH implementations. Using this | |
713 | parameter will force ia64_sal_cache_flush to call | |
714 | ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. | |
715 | ||
d9e54076 PZ |
716 | ftrace=[tracer] |
717 | [ftrace] will set and start the specified tracer | |
718 | as early as possible in order to facilitate early | |
719 | boot debugging. | |
720 | ||
721 | ftrace_dump_on_oops | |
722 | [ftrace] will dump the trace buffers on oops. | |
723 | ||
1da177e4 LT |
724 | gamecon.map[2|3]= |
725 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad | |
726 | support via parallel port (up to 5 devices per port) | |
727 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> | |
728 | See also Documentation/input/joystick-parport.txt | |
729 | ||
730 | gamma= [HW,DRM] | |
731 | ||
aaf23042 YL |
732 | gart_fix_e820= [X86_64] disable the fix e820 for K8 GART |
733 | Format: off | on | |
734 | default: on | |
735 | ||
1da177e4 LT |
736 | gdth= [HW,SCSI] |
737 | See header of drivers/scsi/gdth.c. | |
738 | ||
739 | gpt [EFI] Forces disk with valid GPT signature but | |
740 | invalid Protective MBR to be treated as GPT. | |
741 | ||
1da177e4 LT |
742 | gvp11= [HW,SCSI] |
743 | ||
744 | hashdist= [KNL,NUMA] Large hashes allocated during boot | |
745 | are distributed across NUMA nodes. Defaults on | |
746 | for IA-64, off otherwise. | |
a9913044 | 747 | Format: 0 | 1 (for off | on) |
1da177e4 LT |
748 | |
749 | hcl= [IA-64] SGI's Hardware Graph compatibility layer | |
750 | ||
751 | hd= [EIDE] (E)IDE hard drive subsystem geometry | |
752 | Format: <cyl>,<head>,<sect> | |
753 | ||
1da177e4 LT |
754 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact |
755 | size of <nn>. This works even on boxes that have no | |
756 | highmem otherwise. This also works to reduce highmem | |
757 | size on bigger boxes. | |
758 | ||
54cdfdb4 TG |
759 | highres= [KNL] Enable/disable high resolution timer mode. |
760 | Valid parameters: "on", "off" | |
761 | Default: "on" | |
762 | ||
1da177e4 LT |
763 | hisax= [HW,ISDN] |
764 | See Documentation/isdn/README.HiSax. | |
765 | ||
0cb55ad2 RD |
766 | hlt [BUGS=ARM,SH] |
767 | ||
768 | hpet= [X86-32,HPET] option to control HPET usage | |
769 | Format: { enable (default) | disable | force | | |
770 | verbose } | |
771 | disable: disable HPET and use PIT instead | |
772 | force: allow force enabled of undocumented chips (ICH4, | |
773 | VIA, nVidia) | |
774 | verbose: show contents of HPET registers during setup | |
775 | ||
b4718e62 AK |
776 | hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. |
777 | hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. | |
0d9ea754 JT |
778 | On x86-64 and powerpc, this option can be specified |
779 | multiple times interleaved with hugepages= to reserve | |
780 | huge pages of different sizes. Valid pages sizes on | |
781 | x86-64 are 2M (when the CPU supports "pse") and 1G | |
782 | (when the CPU supports the "pdpe1gb" cpuinfo flag) | |
b4718e62 AK |
783 | Note that 1GB pages can only be allocated at boot time |
784 | using hugepages= and not freed afterwards. | |
6902aa84 | 785 | |
555d61d6 HB |
786 | hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) |
787 | terminal devices. Valid values: 0..8 | |
431429ff HB |
788 | hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. |
789 | If specified, z/VM IUCV HVC accepts connections | |
790 | from listed z/VM user IDs only. | |
cef7125d | 791 | |
3a853fb9 | 792 | i2c_bus= [HW] Override the default board specific I2C bus speed |
7954763b JN |
793 | or register an additional I2C bus that is not |
794 | registered from board initialization code. | |
3a853fb9 JN |
795 | Format: |
796 | <bus_id>,<clkrate> | |
797 | ||
36d95739 | 798 | i8042.debug [HW] Toggle i8042 debug mode |
1da177e4 | 799 | i8042.direct [HW] Put keyboard port into non-translated mode |
84eb8d06 ML |
800 | i8042.dumbkbd [HW] Pretend that controller can only read data from |
801 | keyboard and cannot control its state | |
1da177e4 LT |
802 | (Don't attempt to blink the leds) |
803 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port | |
945ef0d4 | 804 | i8042.nokbd [HW] Don't check/create keyboard port |
75d08c78 JK |
805 | i8042.noloop [HW] Disable the AUX Loopback command while probing |
806 | for the AUX port | |
1da177e4 LT |
807 | i8042.nomux [HW] Don't check presence of an active multiplexing |
808 | controller | |
809 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX | |
810 | controllers | |
811 | i8042.panicblink= | |
812 | [HW] Frequency with which keyboard LEDs should blink | |
813 | when kernel panics (default is 0.5 sec) | |
814 | i8042.reset [HW] Reset the controller during init and cleanup | |
815 | i8042.unlock [HW] Unlock (ignore) the keylock | |
816 | ||
817 | i810= [HW,DRM] | |
818 | ||
e70c9d5e DT |
819 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data |
820 | indicates that the driver is running on unsupported | |
821 | hardware. | |
1da177e4 LT |
822 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature |
823 | does not match list of supported models. | |
824 | i8k.power_status | |
825 | [HW] Report power status in /proc/i8k | |
826 | (disabled by default) | |
827 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN | |
828 | capability is set. | |
829 | ||
830 | ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter | |
831 | See Documentation/mca.txt. | |
832 | ||
833 | icn= [HW,ISDN] | |
834 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] | |
835 | ||
0af80c04 DF |
836 | ide-core.nodma= [HW] (E)IDE subsystem |
837 | Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc | |
838 | .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom | |
839 | .chs .ignore_cable are additional options | |
1c10e938 | 840 | See Documentation/ide/ide.txt. |
1da177e4 | 841 | |
1da177e4 | 842 | idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed |
1c10e938 | 843 | See Documentation/ide/ide.txt. |
1da177e4 | 844 | |
0cb55ad2 RD |
845 | ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem |
846 | Claim all unknown PCI IDE storage controllers. | |
847 | ||
f039b754 | 848 | idle= [X86] |
ada9cfdd RD |
849 | Format: idle=poll, idle=mwait, idle=halt, idle=nomwait |
850 | Poll forces a polling idle loop that can slightly | |
851 | improve the performance of waking up a idle CPU, but | |
852 | will use a lot of power and make the system run hot. | |
853 | Not recommended. | |
854 | idle=mwait: On systems which support MONITOR/MWAIT but | |
855 | the kernel chose to not use it because it doesn't save | |
856 | as much power as a normal idle loop, use the | |
857 | MONITOR/MWAIT idle loop anyways. Performance should be | |
858 | the same as idle=poll. | |
859 | idle=halt: Halt is forced to be used for CPU idle. | |
c1e3b377 | 860 | In such case C2/C3 won't be used again. |
ada9cfdd | 861 | idle=nomwait: Disable mwait for CPU C-states |
a9913044 | 862 | |
79290822 IM |
863 | ignore_loglevel [KNL] |
864 | Ignore loglevel setting - this will print /all/ | |
865 | kernel messages to the console. Useful for debugging. | |
866 | ||
1da177e4 LT |
867 | ihash_entries= [KNL] |
868 | Set number of hash buckets for inode cache. | |
869 | ||
3323eec9 MZ |
870 | ima_audit= [IMA] |
871 | Format: { "0" | "1" } | |
872 | 0 -- integrity auditing messages. (Default) | |
873 | 1 -- enable informational integrity auditing messages. | |
874 | ||
875 | ima_hash= [IMA] | |
876 | Formt: { "sha1" | "md5" } | |
877 | default: "sha1" | |
878 | ||
1da177e4 LT |
879 | in2000= [HW,SCSI] |
880 | See header of drivers/scsi/in2000.c. | |
881 | ||
882 | init= [KNL] | |
883 | Format: <full_path> | |
884 | Run specified binary instead of /sbin/init as init | |
885 | process. | |
886 | ||
887 | initcall_debug [KNL] Trace initcalls as they are executed. Useful | |
888 | for working out where the kernel is dying during | |
889 | startup. | |
890 | ||
891 | initrd= [BOOT] Specify the location of the initial ramdisk | |
892 | ||
893 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver | |
894 | Format: <irq> | |
895 | ||
ba395927 | 896 | intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option |
0cd5c3c8 KM |
897 | on |
898 | Enable intel iommu driver. | |
ba395927 KA |
899 | off |
900 | Disable intel iommu driver. | |
901 | igfx_off [Default Off] | |
902 | By default, gfx is mapped as normal device. If a gfx | |
903 | device has a dedicated DMAR unit, the DMAR unit is | |
904 | bypassed by not enabling DMAR with this option. In | |
905 | this case, gfx device will use physical address for | |
906 | DMA. | |
7d3b03ce KA |
907 | forcedac [x86_64] |
908 | With this option iommu will not optimize to look | |
909 | for io virtual address below 32 bit forcing dual | |
910 | address cycle on pci bus for cards supporting greater | |
911 | than 32 bit addressing. The default is to look | |
912 | for translation below 32 bit and if not available | |
913 | then look in the higher range. | |
5e0d2a6f | 914 | strict [Default Off] |
915 | With this option on every unmap_single operation will | |
916 | result in a hardware IOTLB flush operation as opposed | |
917 | to batching them for performance. | |
ba395927 | 918 | |
0cb55ad2 RD |
919 | inttest= [IA64] |
920 | ||
921 | iomem= Disable strict checking of access to MMIO memory | |
922 | strict regions from userspace. | |
923 | relaxed | |
924 | ||
925 | iommu= [x86] | |
926 | off | |
927 | force | |
928 | noforce | |
929 | biomerge | |
930 | panic | |
931 | nopanic | |
932 | merge | |
933 | nomerge | |
934 | forcesac | |
935 | soft | |
936 | ||
937 | io7= [HW] IO7 for Marvel based alpha systems | |
938 | See comment before marvel_specify_io7 in | |
939 | arch/alpha/kernel/core_marvel.c. | |
940 | ||
b02aae9c | 941 | io_delay= [X86-32,X86-64] I/O delay method |
6e7c4025 IM |
942 | 0x80 |
943 | Standard port 0x80 based delay | |
944 | 0xed | |
945 | Alternate port 0xed based delay (needed on some systems) | |
b02aae9c | 946 | udelay |
6e7c4025 IM |
947 | Simple two microseconds delay |
948 | none | |
949 | No delay | |
b02aae9c | 950 | |
1da177e4 | 951 | ip= [IP_PNP] |
6ded55da | 952 | See Documentation/filesystems/nfsroot.txt. |
1da177e4 LT |
953 | |
954 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards | |
c8facbb6 RD |
955 | See comment before ip2_setup() in |
956 | drivers/char/ip2/ip2base.c. | |
1da177e4 LT |
957 | |
958 | ips= [HW,SCSI] Adaptec / IBM ServeRAID controller | |
959 | See header of drivers/scsi/ips.c. | |
960 | ||
200803df AC |
961 | irqfixup [HW] |
962 | When an interrupt is not handled search all handlers | |
963 | for it. Intended to get systems with badly broken | |
964 | firmware running. | |
965 | ||
966 | irqpoll [HW] | |
967 | When an interrupt is not handled search all handlers | |
968 | for it. Also check all handlers each timer | |
969 | interrupt. Intended to get systems with badly broken | |
970 | firmware running. | |
971 | ||
1da177e4 | 972 | isapnp= [ISAPNP] |
a9913044 | 973 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> |
1da177e4 LT |
974 | |
975 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. | |
22f2e280 DF |
976 | Format: |
977 | <cpu number>,...,<cpu number> | |
978 | or | |
b225d44e LZ |
979 | <cpu number>-<cpu number> |
980 | (must be a positive range in ascending order) | |
22f2e280 DF |
981 | or a mixture |
982 | <cpu number>,...,<cpu number>-<cpu number> | |
b225d44e | 983 | |
1da177e4 LT |
984 | This option can be used to specify one or more CPUs |
985 | to isolate from the general SMP balancing and scheduling | |
b225d44e LZ |
986 | algorithms. You can move a process onto or off an |
987 | "isolated" CPU via the CPU affinity syscalls or cpuset. | |
1da177e4 LT |
988 | <cpu number> begins at 0 and the maximum value is |
989 | "number of CPUs in system - 1". | |
990 | ||
991 | This option is the preferred way to isolate CPUs. The | |
a9913044 RD |
992 | alternative -- manually setting the CPU mask of all |
993 | tasks in the system -- can cause problems and | |
994 | suboptimal load balancer performance. | |
1da177e4 | 995 | |
a9913044 | 996 | iucv= [HW,NET] |
1da177e4 LT |
997 | |
998 | js= [HW,JOY] Analog joystick | |
999 | See Documentation/input/joystick.txt. | |
1000 | ||
0cb55ad2 RD |
1001 | keepinitrd [HW,ARM] |
1002 | ||
cd4f0ef7 | 1003 | kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter |
ed7ed365 MG |
1004 | specifies the amount of memory usable by the kernel |
1005 | for non-movable allocations. The requested amount is | |
1006 | spread evenly throughout all nodes in the system. The | |
1007 | remaining memory in each node is used for Movable | |
1008 | pages. In the event, a node is too small to have both | |
1009 | kernelcore and Movable pages, kernelcore pages will | |
1010 | take priority and other nodes will have a larger number | |
1011 | of kernelcore pages. The Movable zone is used for the | |
1012 | allocation of pages that may be reclaimed or moved | |
1013 | by the page migration subsystem. This means that | |
1014 | HugeTLB pages may not be allocated from this zone. | |
1015 | Note that allocations like PTEs-from-HighMem still | |
1016 | use the HighMem zone if it exists, and the Normal | |
1017 | zone if it does not. | |
1018 | ||
b9ce08c0 EGM |
1019 | kmemtrace.enable= [KNL,KMEMTRACE] Format: { yes | no } |
1020 | Controls whether kmemtrace is enabled | |
1021 | at boot-time. | |
1022 | ||
1023 | kmemtrace.subbufs=n [KNL,KMEMTRACE] Overrides the number of | |
1024 | subbufs kmemtrace's relay channel has. Set this | |
1025 | higher than default (KMEMTRACE_N_SUBBUFS in code) if | |
1026 | you experience buffer overruns. | |
1027 | ||
6cdf6e06 JW |
1028 | kgdboc= [HW] kgdb over consoles. |
1029 | Requires a tty driver that supports console polling. | |
1030 | (only serial suported for now) | |
1031 | Format: <serial_device>[,baud] | |
1032 | ||
9bed90c6 FF |
1033 | kmac= [MIPS] korina ethernet MAC address. |
1034 | Configure the RouterBoard 532 series on-chip | |
1035 | Ethernet adapter MAC address. | |
1036 | ||
0cb55ad2 RD |
1037 | kstack=N [X86-32,X86-64] Print N words from the kernel stack |
1038 | in oops dumps. | |
1039 | ||
1da177e4 LT |
1040 | l2cr= [PPC] |
1041 | ||
a78bfbfc RB |
1042 | l3cr= [PPC] |
1043 | ||
cd4f0ef7 | 1044 | lapic [X86-32,APIC] Enable the local APIC even if BIOS |
a9913044 | 1045 | disabled it. |
1da177e4 | 1046 | |
ada9cfdd RD |
1047 | lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer |
1048 | in C2 power state. | |
e585bef8 | 1049 | |
fcb71f6f FC |
1050 | libata.dma= [LIBATA] DMA control |
1051 | libata.dma=0 Disable all PATA and SATA DMA | |
1052 | libata.dma=1 PATA and SATA Disk DMA only | |
1053 | libata.dma=2 ATAPI (CDROM) DMA only | |
1054 | libata.dma=4 Compact Flash DMA only | |
1055 | Combinations also work, so libata.dma=3 enables DMA | |
1056 | for disks and CDROMs, but not CFs. | |
1057 | ||
78e70c23 DJ |
1058 | libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume |
1059 | when set. | |
1060 | Format: <int> | |
1061 | ||
33267325 TH |
1062 | libata.force= [LIBATA] Force configurations. The format is comma |
1063 | separated list of "[ID:]VAL" where ID is | |
1064 | PORT[:DEVICE]. PORT and DEVICE are decimal numbers | |
1065 | matching port, link or device. Basically, it matches | |
1066 | the ATA ID string printed on console by libata. If | |
1067 | the whole ID part is omitted, the last PORT and DEVICE | |
1068 | values are used. If ID hasn't been specified yet, the | |
1069 | configuration applies to all ports, links and devices. | |
1070 | ||
1071 | If only DEVICE is omitted, the parameter applies to | |
1072 | the port and all links and devices behind it. DEVICE | |
1073 | number of 0 either selects the first device or the | |
1074 | first fan-out link behind PMP device. It does not | |
1075 | select the host link. DEVICE number of 15 selects the | |
1076 | host link and device attached to it. | |
1077 | ||
1078 | The VAL specifies the configuration to force. As long | |
1079 | as there's no ambiguity shortcut notation is allowed. | |
1080 | For example, both 1.5 and 1.5G would work for 1.5Gbps. | |
1081 | The following configurations can be forced. | |
1082 | ||
1083 | * Cable type: 40c, 80c, short40c, unk, ign or sata. | |
1084 | Any ID with matching PORT is used. | |
1085 | ||
1086 | * SATA link speed limit: 1.5Gbps or 3.0Gbps. | |
1087 | ||
1088 | * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7]. | |
1089 | udma[/][16,25,33,44,66,100,133] notation is also | |
1090 | allowed. | |
1091 | ||
1092 | * [no]ncq: Turn on or off NCQ. | |
1093 | ||
05944bdf TH |
1094 | * nohrst, nosrst, norst: suppress hard, soft |
1095 | and both resets. | |
1096 | ||
33267325 TH |
1097 | If there are multiple matching configurations changing |
1098 | the same attribute, the last one is used. | |
1099 | ||
7c4be253 RD |
1100 | lmb=debug [KNL] Enable lmb debug messages. |
1101 | ||
1da177e4 | 1102 | load_ramdisk= [RAM] List of ramdisks to load from floppy |
31c00fc1 | 1103 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 1104 | |
a6b25b67 RD |
1105 | lockd.nlm_grace_period=P [NFS] Assign grace period. |
1106 | Format: <integer> | |
1da177e4 | 1107 | |
a6b25b67 RD |
1108 | lockd.nlm_tcpport=N [NFS] Assign TCP port. |
1109 | Format: <integer> | |
1110 | ||
1111 | lockd.nlm_timeout=T [NFS] Assign timeout value. | |
1112 | Format: <integer> | |
1113 | ||
1114 | lockd.nlm_udpport=M [NFS] Assign UDP port. | |
1115 | Format: <integer> | |
1da177e4 LT |
1116 | |
1117 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver | |
1118 | Format: <irq> | |
1119 | ||
1120 | loglevel= All Kernel Messages with a loglevel smaller than the | |
1121 | console loglevel will be printed to the console. It can | |
1122 | also be changed with klogd or other programs. The | |
1123 | loglevels are defined as follows: | |
1124 | ||
1125 | 0 (KERN_EMERG) system is unusable | |
1126 | 1 (KERN_ALERT) action must be taken immediately | |
1127 | 2 (KERN_CRIT) critical conditions | |
1128 | 3 (KERN_ERR) error conditions | |
1129 | 4 (KERN_WARNING) warning conditions | |
1130 | 5 (KERN_NOTICE) normal but significant condition | |
1131 | 6 (KERN_INFO) informational | |
1132 | 7 (KERN_DEBUG) debug-level messages | |
1133 | ||
1134 | log_buf_len=n Sets the size of the printk ring buffer, in bytes. | |
a9913044 RD |
1135 | Format: { n | nk | nM } |
1136 | n must be a power of two. The default size | |
1137 | is set in the kernel config file. | |
1da177e4 | 1138 | |
accaa24c RD |
1139 | logo.nologo [FB] Disables display of the built-in Linux logo. |
1140 | This may be used to provide more screen space for | |
1141 | kernel log messages and is useful when debugging | |
1142 | kernel boot problems. | |
1143 | ||
1da177e4 LT |
1144 | lp=0 [LP] Specify parallel ports to use, e.g, |
1145 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses | |
1146 | lp=reset first parallel port). 'lp=0' disables the | |
1147 | lp=auto printer driver. 'lp=reset' (which can be | |
1148 | specified in addition to the ports) causes | |
1149 | attached printers to be reset. Using | |
1150 | lp=port1,port2,... specifies the parallel ports | |
1151 | to associate lp devices with, starting with | |
1152 | lp0. A port specification may be 'none' to skip | |
1153 | that lp device, or a parport name such as | |
1154 | 'parport0'. Specifying 'lp=auto' instead of a | |
1155 | port specification list means that device IDs | |
1156 | from each port should be examined, to see if | |
1157 | an IEEE 1284-compliant printer is attached; if | |
1158 | so, the driver will manage that printer. | |
1159 | See also header of drivers/char/lp.c. | |
1160 | ||
1161 | lpj=n [KNL] | |
1162 | Sets loops_per_jiffy to given constant, thus avoiding | |
1163 | time-consuming boot-time autodetection (up to 250 ms per | |
1164 | CPU). 0 enables autodetection (default). To determine | |
1165 | the correct value for your kernel, boot with normal | |
1166 | autodetection and see what value is printed. Note that | |
1167 | on SMP systems the preset will be applied to all CPUs, | |
1168 | which is likely to cause problems if your CPUs need | |
1169 | significantly divergent settings. An incorrect value | |
1170 | will cause delays in the kernel to be wrong, leading to | |
1171 | unpredictable I/O errors and other breakage. Although | |
1172 | unlikely, in the extreme case this might damage your | |
1173 | hardware. | |
1174 | ||
1175 | ltpc= [NET] | |
1176 | Format: <io>,<irq>,<dma> | |
1177 | ||
a9913044 RD |
1178 | mac5380= [HW,SCSI] Format: |
1179 | <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 1180 | |
a9913044 RD |
1181 | machvec= [IA64] Force the use of a particular machine-vector |
1182 | (machvec) in a generic kernel. | |
1183 | Example: machvec=hpzx1_swiotlb | |
1da177e4 | 1184 | |
0cb55ad2 RD |
1185 | max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater |
1186 | than or equal to this physical address is ignored. | |
1da177e4 LT |
1187 | |
1188 | maxcpus= [SMP] Maximum number of processors that an SMP kernel | |
61ec7567 LB |
1189 | should make use of. maxcpus=n : n >= 0 limits the |
1190 | kernel to using 'n' processors. n=0 is a special case, | |
1191 | it is equivalent to "nosmp", which also disables | |
1192 | the IO APIC. | |
1da177e4 | 1193 | |
0cb55ad2 RD |
1194 | max_loop= [LOOP] Maximum number of loopback devices that can |
1195 | be mounted | |
1196 | Format: <1-256> | |
2b2c3750 | 1197 | |
a9913044 | 1198 | max_luns= [SCSI] Maximum number of LUNs to probe. |
1da177e4 LT |
1199 | Should be between 1 and 2^32-1. |
1200 | ||
1201 | max_report_luns= | |
a9913044 | 1202 | [SCSI] Maximum number of LUNs received. |
1da177e4 LT |
1203 | Should be between 1 and 16384. |
1204 | ||
1da177e4 LT |
1205 | mcatest= [IA-64] |
1206 | ||
cd4f0ef7 | 1207 | mce [X86-32] Machine Check Exception |
1da177e4 | 1208 | |
71cced6e | 1209 | mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt |
909dd324 | 1210 | |
1da177e4 LT |
1211 | md= [HW] RAID subsystems devices and level |
1212 | See Documentation/md.txt. | |
a9913044 | 1213 | |
1da177e4 LT |
1214 | mdacon= [MDA] |
1215 | Format: <first>,<last> | |
1216 | Specifies range of consoles to be captured by the MDA. | |
a9913044 | 1217 | |
1da177e4 LT |
1218 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory |
1219 | Amount of memory to be used when the kernel is not able | |
1220 | to see the whole system memory or for test. | |
cd4f0ef7 | 1221 | [X86-32] Use together with memmap= to avoid physical |
1da177e4 LT |
1222 | address space collisions. Without memmap= PCI devices |
1223 | could be placed at addresses belonging to unused RAM. | |
1224 | ||
cd4f0ef7 | 1225 | mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel |
1da177e4 LT |
1226 | memory. |
1227 | ||
6902aa84 PM |
1228 | memchunk=nn[KMG] |
1229 | [KNL,SH] Allow user to override the default size for | |
1230 | per-device physically contiguous DMA buffers. | |
1231 | ||
cd4f0ef7 | 1232 | memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact |
1da177e4 LT |
1233 | E820 memory map, as specified by the user. |
1234 | Such memmap=exactmap lines can be constructed based on | |
1235 | BIOS output or other requirements. See the memmap=nn@ss | |
1236 | option description. | |
1237 | ||
1238 | memmap=nn[KMG]@ss[KMG] | |
1239 | [KNL] Force usage of a specific region of memory | |
1240 | Region of memory to be used, from ss to ss+nn. | |
1241 | ||
1242 | memmap=nn[KMG]#ss[KMG] | |
1243 | [KNL,ACPI] Mark specific memory as ACPI data. | |
1244 | Region of memory to be used, from ss to ss+nn. | |
1245 | ||
1246 | memmap=nn[KMG]$ss[KMG] | |
1247 | [KNL,ACPI] Mark specific memory as reserved. | |
1248 | Region of memory to be used, from ss to ss+nn. | |
1312848e PM |
1249 | Example: Exclude memory from 0x18690000-0x1869ffff |
1250 | memmap=64K$0x18690000 | |
1251 | or | |
1252 | memmap=0x10000$0x18690000 | |
1da177e4 | 1253 | |
9f077871 JF |
1254 | memory_corruption_check=0/1 [X86] |
1255 | Some BIOSes seem to corrupt the first 64k of | |
1256 | memory when doing things like suspend/resume. | |
1257 | Setting this option will scan the memory | |
1258 | looking for corruption. Enabling this will | |
1259 | both detect corruption and prevent the kernel | |
1260 | from using the memory being corrupted. | |
1261 | However, its intended as a diagnostic tool; if | |
1262 | repeatable BIOS-originated corruption always | |
1263 | affects the same memory, you can use memmap= | |
1264 | to prevent the kernel from using that memory. | |
1265 | ||
1266 | memory_corruption_check_size=size [X86] | |
1267 | By default it checks for corruption in the low | |
1268 | 64k, making this memory unavailable for normal | |
1269 | use. Use this parameter to scan for | |
1270 | corruption in more or less memory. | |
1271 | ||
1272 | memory_corruption_check_period=seconds [X86] | |
1273 | By default it checks for corruption every 60 | |
1274 | seconds. Use this parameter to check at some | |
1275 | other rate. 0 disables periodic checking. | |
1276 | ||
caadbdce | 1277 | memtest= [KNL,X86] Enable memtest |
c64df707 | 1278 | Format: <integer> |
c64df707 | 1279 | default : 0 <disable> |
9e5f6cf5 AH |
1280 | Specifies the number of memtest passes to be |
1281 | performed. Each pass selects another test | |
1282 | pattern from a given set of patterns. Memtest | |
1283 | fills the memory with this pattern, validates | |
1284 | memory contents and reserves bad memory | |
1285 | regions that are detected. | |
c64df707 | 1286 | |
1da177e4 LT |
1287 | meye.*= [HW] Set MotionEye Camera parameters |
1288 | See Documentation/video4linux/meye.txt. | |
1289 | ||
8f36881b AS |
1290 | mfgpt_irq= [IA-32] Specify the IRQ to use for the |
1291 | Multi-Function General Purpose Timers on AMD Geode | |
1292 | platforms. | |
1293 | ||
e6c4dc6c WT |
1294 | mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when |
1295 | the BIOS has incorrectly applied a workaround. TinyBIOS | |
1296 | version 0.98 is known to be affected, 0.99 fixes the | |
1297 | problem by letting the user disable the workaround. | |
1298 | ||
1da177e4 LT |
1299 | mga= [HW,DRM] |
1300 | ||
1c207f95 RD |
1301 | min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this |
1302 | physical address is ignored. | |
1303 | ||
6b74ab97 MG |
1304 | mminit_loglevel= |
1305 | [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this | |
1306 | parameter allows control of the logging verbosity for | |
1307 | the additional memory initialisation checks. A value | |
1308 | of 0 disables mminit logging and a level of 4 will | |
1309 | log everything. Information is printed at KERN_DEBUG | |
1310 | so loglevel=8 may also need to be specified. | |
1311 | ||
1da177e4 LT |
1312 | mousedev.tap_time= |
1313 | [MOUSE] Maximum time between finger touching and | |
1314 | leaving touchpad surface for touch to be considered | |
1315 | a tap and be reported as a left button click (for | |
1316 | touchpads working in absolute mode only). | |
1317 | Format: <msecs> | |
1318 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices | |
1319 | reporting absolute coordinates, such as tablets | |
1320 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices | |
1321 | reporting absolute coordinates, such as tablets | |
1322 | ||
0cb55ad2 RD |
1323 | movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter |
1324 | is similar to kernelcore except it specifies the | |
1325 | amount of memory used for migratable allocations. | |
1326 | If both kernelcore and movablecore is specified, | |
1327 | then kernelcore will be at *least* the specified | |
1328 | value but may be more. If movablecore on its own | |
1329 | is specified, the administrator must be careful | |
1330 | that the amount of memory usable for all allocations | |
1331 | is not too small. | |
1332 | ||
1da177e4 LT |
1333 | mpu401= [HW,OSS] |
1334 | Format: <io>,<irq> | |
1335 | ||
1336 | MTD_Partition= [MTD] | |
1337 | Format: <name>,<region-number>,<size>,<offset> | |
1338 | ||
a9913044 RD |
1339 | MTD_Region= [MTD] Format: |
1340 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] | |
1da177e4 LT |
1341 | |
1342 | mtdparts= [MTD] | |
c8facbb6 | 1343 | See drivers/mtd/cmdlinepart.c. |
1da177e4 | 1344 | |
9db829f4 BD |
1345 | mtdset= [ARM] |
1346 | ARM/S3C2412 JIVE boot control | |
1347 | ||
1348 | See arch/arm/mach-s3c2412/mach-jive.c | |
1349 | ||
1da177e4 | 1350 | mtouchusb.raw_coordinates= |
a9913044 RD |
1351 | [HW] Make the MicroTouch USB driver use raw coordinates |
1352 | ('y', default) or cooked coordinates ('n') | |
1da177e4 | 1353 | |
0cb55ad2 RD |
1354 | mtrr_chunk_size=nn[KMG] [X86] |
1355 | used for mtrr cleanup. It is largest continous chunk | |
1356 | that could hold holes aka. UC entries. | |
1357 | ||
1358 | mtrr_gran_size=nn[KMG] [X86] | |
1359 | Used for mtrr cleanup. It is granularity of mtrr block. | |
1360 | Default is 1. | |
1361 | Large value could prevent small alignment from | |
1362 | using up MTRRs. | |
1363 | ||
1364 | mtrr_spare_reg_nr=n [X86] | |
1365 | Format: <integer> | |
1366 | Range: 0,7 : spare reg number | |
1367 | Default : 1 | |
1368 | Used for mtrr cleanup. It is spare mtrr entries number. | |
1369 | Set to 2 or more if your graphical card needs more. | |
1370 | ||
1da177e4 LT |
1371 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card |
1372 | ||
1373 | NCR_D700= [HW,SCSI] | |
1374 | See header of drivers/scsi/NCR_D700.c. | |
1375 | ||
1376 | ncr5380= [HW,SCSI] | |
1377 | ||
1378 | ncr53c400= [HW,SCSI] | |
1379 | ||
1380 | ncr53c400a= [HW,SCSI] | |
1381 | ||
1382 | ncr53c406a= [HW,SCSI] | |
1383 | ||
1384 | ncr53c8xx= [HW,SCSI] | |
1385 | ||
1386 | netdev= [NET] Network devices parameters | |
1387 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> | |
1388 | Note that mem_start is often overloaded to mean | |
1389 | something different and driver-specific. | |
a9913044 RD |
1390 | This usage is only documented in each driver source |
1391 | file if at all. | |
1392 | ||
58401572 KPO |
1393 | nf_conntrack.acct= |
1394 | [NETFILTER] Enable connection tracking flow accounting | |
1395 | 0 to disable accounting | |
1396 | 1 to enable accounting | |
1397 | Default value depends on CONFIG_NF_CT_ACCT that is | |
1398 | going to be removed in 2.6.29. | |
1399 | ||
1da177e4 | 1400 | nfsaddrs= [NFS] |
6ded55da | 1401 | See Documentation/filesystems/nfsroot.txt. |
1da177e4 LT |
1402 | |
1403 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. | |
6ded55da | 1404 | See Documentation/filesystems/nfsroot.txt. |
1da177e4 | 1405 | |
a72b4422 TM |
1406 | nfs.callback_tcpport= |
1407 | [NFS] set the TCP port on which the NFSv4 callback | |
1408 | channel should listen. | |
1409 | ||
58df095b TM |
1410 | nfs.idmap_cache_timeout= |
1411 | [NFS] set the maximum lifetime for idmapper cache | |
1412 | entries. | |
1413 | ||
f43bf0be TM |
1414 | nfs.enable_ino64= |
1415 | [NFS] enable 64-bit inode numbers. | |
1416 | If zero, the NFS client will fake up a 32-bit inode | |
1417 | number for the readdir() and stat() syscalls instead | |
1418 | of returning the full 64-bit number. | |
1419 | The default is to return 64-bit inode numbers. | |
1420 | ||
e7ba176b HS |
1421 | nmi_debug= [KNL,AVR32] Specify one or more actions to take |
1422 | when a NMI is triggered. | |
1423 | Format: [state][,regs][,debounce][,die] | |
1424 | ||
5b9a0e14 CG |
1425 | nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels |
1426 | Format: [panic,][num] | |
1427 | Valid num: 0,1,2 | |
1428 | 0 - turn nmi_watchdog off | |
1429 | 1 - use the IO-APIC timer for the NMI watchdog | |
1430 | 2 - use the local APIC for the NMI watchdog using | |
0cb55ad2 RD |
1431 | a performance counter. Note: This will use one |
1432 | performance counter and the local APIC's performance | |
1433 | vector. | |
1434 | When panic is specified, panic when an NMI watchdog | |
1435 | timeout occurs. | |
1436 | This is useful when you use a panic=... timeout and | |
1437 | need the box quickly up again. | |
5b9a0e14 CG |
1438 | Instead of 1 and 2 it is possible to use the following |
1439 | symbolic names: lapic and ioapic | |
1440 | Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic | |
1da177e4 | 1441 | |
cd4f0ef7 | 1442 | no387 [BUGS=X86-32] Tells the kernel to use the 387 maths |
1da177e4 LT |
1443 | emulation library even if a 387 maths coprocessor |
1444 | is present. | |
1445 | ||
0cb55ad2 RD |
1446 | no_console_suspend |
1447 | [HW] Never suspend the console | |
1448 | Disable suspending of consoles during suspend and | |
1449 | hibernate operations. Once disabled, debugging | |
1450 | messages can reach various consoles while the rest | |
1451 | of the system is being put to sleep (ie, while | |
1452 | debugging driver suspend/resume hooks). This may | |
1453 | not work reliably with all consoles, but is known | |
1454 | to work with serial and VGA consoles. | |
1455 | ||
c1aee215 CL |
1456 | noaliencache [MM, NUMA, SLAB] Disables the allocation of alien |
1457 | caches in the slab allocator. Saves per-node memory, | |
1458 | but will impact performance. | |
3395ee05 | 1459 | |
a9913044 RD |
1460 | noalign [KNL,ARM] |
1461 | ||
1da177e4 LT |
1462 | noapic [SMP,APIC] Tells the kernel to not make use of any |
1463 | IOAPICs that may be present in the system. | |
1464 | ||
1da177e4 LT |
1465 | nobats [PPC] Do not use BATs for mapping kernel lowmem |
1466 | on "Classic" PPC cores. | |
1467 | ||
1468 | nocache [ARM] | |
a9913044 | 1469 | |
0cb55ad2 RD |
1470 | noclflush [BUGS=X86] Don't use the CLFLUSH instruction |
1471 | ||
163ecdff SN |
1472 | nodelayacct [KNL] Disable per-task delay accounting |
1473 | ||
1da177e4 LT |
1474 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. |
1475 | ||
6902aa84 PM |
1476 | nodsp [SH] Disable hardware DSP at boot time. |
1477 | ||
8b2cb7a8 HY |
1478 | noefi [X86-32,X86-64] Disable EFI runtime services support. |
1479 | ||
1da177e4 LT |
1480 | noexec [IA-64] |
1481 | ||
cd4f0ef7 | 1482 | noexec [X86-32,X86-64] |
f5a1b191 | 1483 | On X86-32 available only on PAE configured kernels. |
1da177e4 | 1484 | noexec=on: enable non-executable mappings (default) |
f5a1b191 JS |
1485 | noexec=off: disable non-executable mappings |
1486 | ||
1487 | noexec32 [X86-64] | |
1488 | This affects only 32-bit executables. | |
1489 | noexec32=on: enable non-executable mappings (default) | |
1490 | read doesn't imply executable mappings | |
1491 | noexec32=off: disable non-executable mappings | |
1492 | read implies executable mappings | |
1da177e4 | 1493 | |
6902aa84 PM |
1494 | nofpu [SH] Disable hardware FPU at boot time. |
1495 | ||
cd4f0ef7 | 1496 | nofxsr [BUGS=X86-32] Disables x86 floating point extended |
4f886511 CE |
1497 | register save and restore. The kernel will only save |
1498 | legacy floating-point registers on task switch. | |
1da177e4 | 1499 | |
01a24d2b PZ |
1500 | nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or |
1501 | wfi(ARM) instruction doesn't work correctly and not to | |
1502 | use it. This is also useful when using JTAG debugger. | |
a9913044 | 1503 | |
cd4f0ef7 | 1504 | no-hlt [BUGS=X86-32] Tells the kernel that the hlt |
1da177e4 LT |
1505 | instruction doesn't work correctly and not to |
1506 | use it. | |
1507 | ||
1f29fae2 SH |
1508 | no_file_caps Tells the kernel not to honor file capabilities. The |
1509 | only way then for a file to be executed with privilege | |
1510 | is to be setuid root or executed by root. | |
1511 | ||
1da177e4 LT |
1512 | nohalt [IA-64] Tells the kernel not to use the power saving |
1513 | function PAL_HALT_LIGHT when idle. This increases | |
1514 | power-consumption. On the positive side, it reduces | |
1515 | interrupt wake-up latency, which may improve performance | |
1516 | in certain environments such as networked servers or | |
1517 | real-time systems. | |
1518 | ||
79bf2bb3 TG |
1519 | nohz= [KNL] Boottime enable/disable dynamic ticks |
1520 | Valid arguments: on, off | |
1521 | Default: on | |
1522 | ||
eeee7853 PM |
1523 | noiotrap [SH] Disables trapped I/O port accesses. |
1524 | ||
cd4f0ef7 | 1525 | noirqdebug [X86-32] Disables the code which attempts to detect and |
1da177e4 LT |
1526 | disable unhandled interrupt sources. |
1527 | ||
cd4f0ef7 | 1528 | no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for |
8542b200 ZA |
1529 | broken timer IRQ sources. |
1530 | ||
1da177e4 LT |
1531 | noisapnp [ISAPNP] Disables ISA PnP code. |
1532 | ||
1533 | noinitrd [RAM] Tells the kernel not to load any configured | |
1534 | initial RAM disk. | |
1535 | ||
1536 | nointroute [IA-64] | |
1537 | ||
0aa366f3 TL |
1538 | nojitter [IA64] Disables jitter checking for ITC timers. |
1539 | ||
cd4f0ef7 | 1540 | nolapic [X86-32,APIC] Do not enable or use the local APIC. |
1da177e4 | 1541 | |
cd4f0ef7 | 1542 | nolapic_timer [X86-32,APIC] Do not use the local APIC timer. |
ad62ca2b | 1543 | |
1da177e4 LT |
1544 | noltlbs [PPC] Do not use large page/tlb entries for kernel |
1545 | lowmem mapping on PPC40x. | |
1546 | ||
312f1f01 H |
1547 | nomca [IA-64] Disable machine check abort handling |
1548 | ||
cd4f0ef7 | 1549 | nomce [X86-32] Machine Check Exception |
abe37e5a | 1550 | |
83d7384f AS |
1551 | nomfgpt [X86-32] Disable Multi-Function General Purpose |
1552 | Timer usage (for AMD Geode machines). | |
1553 | ||
0cb55ad2 RD |
1554 | norandmaps Don't use address space randomization. Equivalent to |
1555 | echo 0 > /proc/sys/kernel/randomize_va_space | |
1556 | ||
cd4f0ef7 | 1557 | noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops |
959b4fdf | 1558 | |
cd4f0ef7 | 1559 | noreplace-smp [X86-32,SMP] Don't replace SMP instructions |
b7fb4af0 JF |
1560 | with UP alternatives |
1561 | ||
1da177e4 LT |
1562 | noresidual [PPC] Don't use residual data on PReP machines. |
1563 | ||
a9913044 RD |
1564 | noresume [SWSUSP] Disables resume and restores original swap |
1565 | space. | |
1566 | ||
1da177e4 LT |
1567 | no-scroll [VGA] Disables scrollback. |
1568 | This is required for the Braillex ib80-piezo Braille | |
1569 | reader made by F.H. Papenmeier (Germany). | |
1570 | ||
1571 | nosbagart [IA-64] | |
1572 | ||
cd4f0ef7 | 1573 | nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. |
4f886511 | 1574 | |
61ec7567 LB |
1575 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel, |
1576 | and disable the IO APIC. legacy for "maxcpus=0". | |
1da177e4 | 1577 | |
97842216 DJ |
1578 | nosoftlockup [KNL] Disable the soft-lockup detector. |
1579 | ||
c077719b | 1580 | noswapaccount [KNL] Disable accounting of swap in memory resource |
21acb9ca | 1581 | controller. (See Documentation/cgroups/memory.txt) |
c077719b | 1582 | |
1da177e4 LT |
1583 | nosync [HW,M68K] Disables sync negotiation for all devices. |
1584 | ||
cd4f0ef7 | 1585 | notsc [BUGS=X86-32] Disable Time Stamp Counter |
1da177e4 LT |
1586 | |
1587 | nousb [USB] Disable the USB subsystem | |
1588 | ||
1589 | nowb [ARM] | |
a9913044 | 1590 | |
a6c75b86 FY |
1591 | nptcg= [IA64] Override max number of concurrent global TLB |
1592 | purges which is reported from either PAL_VM_SUMMARY or | |
1593 | SAL PALO. | |
1594 | ||
0cb55ad2 RD |
1595 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. |
1596 | ||
f0c0b2b8 KH |
1597 | numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. |
1598 | one of ['zone', 'node', 'default'] can be specified | |
1599 | This can be set from sysctl after boot. | |
1600 | See Documentation/sysctl/vm.txt for details. | |
1601 | ||
7c4be253 RD |
1602 | ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. |
1603 | See Documentation/debugging-via-ohci1394.txt for more | |
1604 | info. | |
1605 | ||
3ef0e1f8 AS |
1606 | olpc_ec_timeout= [OLPC] ms delay when issuing EC commands |
1607 | Rather than timing out after 20 ms if an EC | |
1608 | command is not properly ACKed, override the length | |
1609 | of the timeout. We have interrupts disabled while | |
1610 | waiting for the ACK, so if this is set too high | |
1611 | interrupts *may* be lost! | |
1612 | ||
1da177e4 LT |
1613 | opl3= [HW,OSS] |
1614 | Format: <io> | |
1615 | ||
1da177e4 LT |
1616 | oprofile.timer= [HW] |
1617 | Use timer interrupt instead of performance counters | |
1618 | ||
1da177e4 LT |
1619 | osst= [HW,SCSI] SCSI Tape Driver |
1620 | Format: <buffer_size>,<write_threshold> | |
1621 | See also Documentation/scsi/st.txt. | |
1622 | ||
1623 | panic= [KNL] Kernel behaviour on panic | |
1624 | Format: <timeout> | |
1625 | ||
1626 | parkbd.port= [HW] Parallel port number the keyboard adapter is | |
1627 | connected to, default is 0. | |
1628 | Format: <parport#> | |
1629 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, | |
1630 | 0 for XT, 1 for AT (default is AT). | |
a9913044 RD |
1631 | Format: <mode> |
1632 | ||
1633 | parport= [HW,PPT] Specify parallel ports. 0 disables. | |
1634 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } | |
1635 | Use 'auto' to force the driver to use any | |
1636 | IRQ/DMA settings detected (the default is to | |
1637 | ignore detected IRQ/DMA settings because of | |
1638 | possible conflicts). You can specify the base | |
1639 | address, IRQ, and DMA settings; IRQ and DMA | |
1640 | should be numbers, or 'auto' (for using detected | |
1641 | settings on that particular port), or 'nofifo' | |
1642 | (to avoid using a FIFO even if it is detected). | |
1643 | Parallel ports are assigned in the order they | |
1644 | are specified on the command line, starting | |
1645 | with parport0. | |
1646 | ||
1647 | parport_init_mode= [HW,PPT] | |
1648 | Configure VIA parallel port to operate in | |
1649 | a specific mode. This is necessary on Pegasos | |
1650 | computer where firmware has no options for setting | |
1651 | up parallel port mode and sets it to spp. | |
1652 | Currently this function knows 686a and 8231 chips. | |
1da177e4 LT |
1653 | Format: [spp|ps2|epp|ecp|ecpepp] |
1654 | ||
a9913044 RD |
1655 | pas2= [HW,OSS] Format: |
1656 | <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16> | |
1657 | ||
1da177e4 LT |
1658 | pas16= [HW,SCSI] |
1659 | See header of drivers/scsi/pas16.c. | |
1660 | ||
dd287796 AM |
1661 | pause_on_oops= |
1662 | Halt all CPUs after the first oops has been printed for | |
1663 | the specified number of seconds. This is to be used if | |
1664 | your oopses keep scrolling off the screen. | |
1665 | ||
1da177e4 LT |
1666 | pcbit= [HW,ISDN] |
1667 | ||
1668 | pcd. [PARIDE] | |
1669 | See header of drivers/block/paride/pcd.c. | |
31c00fc1 | 1670 | See also Documentation/blockdev/paride.txt. |
1da177e4 | 1671 | |
a9913044 | 1672 | pci=option[,option...] [PCI] various PCI subsystem options: |
1cc0ca26 BH |
1673 | earlydump [X86] dump PCI config space before the kernel |
1674 | changes anything | |
c0115606 | 1675 | off [X86] don't probe for the PCI bus |
cd4f0ef7 | 1676 | bios [X86-32] force use of PCI BIOS, don't access |
a9913044 RD |
1677 | the hardware directly. Use this if your machine |
1678 | has a non-standard PCI host bridge. | |
cd4f0ef7 | 1679 | nobios [X86-32] disallow use of PCI BIOS, only direct |
a9913044 RD |
1680 | hardware access methods are allowed. Use this |
1681 | if you experience crashes upon bootup and you | |
1682 | suspect they are caused by the BIOS. | |
c0115606 | 1683 | conf1 [X86] Force use of PCI Configuration |
a9913044 | 1684 | Mechanism 1. |
c0115606 | 1685 | conf2 [X86] Force use of PCI Configuration |
a9913044 | 1686 | Mechanism 2. |
7f785763 RD |
1687 | noaer [PCIE] If the PCIEAER kernel config parameter is |
1688 | enabled, this kernel boot option can be used to | |
1689 | disable the use of PCIE advanced error reporting. | |
32a2eea7 JG |
1690 | nodomains [PCI] Disable support for multiple PCI |
1691 | root domains (aka PCI segments, in ACPI-speak). | |
cd4f0ef7 | 1692 | nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI |
61be6d66 | 1693 | Configuration |
309e57df MW |
1694 | nomsi [MSI] If the PCI_MSI kernel config parameter is |
1695 | enabled, this kernel boot option can be used to | |
1696 | disable the use of MSI interrupts system-wide. | |
a9322f64 SA |
1697 | noioapicquirk [APIC] Disable all boot interrupt quirks. |
1698 | Safety option to keep boot IRQs enabled. This | |
1699 | should never be necessary. | |
9197979b SA |
1700 | ioapicreroute [APIC] Enable rerouting of boot IRQs to the |
1701 | primary IO-APIC for bridges that cannot disable | |
1702 | boot IRQs. This fixes a source of spurious IRQs | |
1703 | when the system masks IRQs. | |
41b9eb26 SA |
1704 | noioapicreroute [APIC] Disable workaround that uses the |
1705 | boot IRQ equivalent of an IRQ that connects to | |
1706 | a chipset where boot IRQs cannot be disabled. | |
1707 | The opposite of ioapicreroute. | |
cd4f0ef7 | 1708 | biosirq [X86-32] Use PCI BIOS calls to get the interrupt |
a9913044 RD |
1709 | routing table. These calls are known to be buggy |
1710 | on several machines and they hang the machine | |
1711 | when used, but on other computers it's the only | |
1712 | way to get the interrupt routing table. Try | |
1713 | this option if the kernel is unable to allocate | |
1714 | IRQs or discover secondary PCI buses on your | |
1715 | motherboard. | |
c0115606 | 1716 | rom [X86] Assign address space to expansion ROMs. |
a9913044 RD |
1717 | Use with caution as certain devices share |
1718 | address decoders between ROMs and other | |
1719 | resources. | |
c0115606 | 1720 | norom [X86] Do not assign address space to |
bb71ad88 GH |
1721 | expansion ROMs that do not already have |
1722 | BIOS assigned address ranges. | |
c0115606 | 1723 | irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be |
a9913044 RD |
1724 | assigned automatically to PCI devices. You can |
1725 | make the kernel exclude IRQs of your ISA cards | |
1726 | this way. | |
c0115606 | 1727 | pirqaddr=0xAAAAA [X86] Specify the physical address |
a9913044 RD |
1728 | of the PIRQ table (normally generated |
1729 | by the BIOS) if it is outside the | |
1730 | F0000h-100000h range. | |
c0115606 | 1731 | lastbus=N [X86] Scan all buses thru bus #N. Can be |
a9913044 RD |
1732 | useful if the kernel is unable to find your |
1733 | secondary buses and you want to tell it | |
1734 | explicitly which ones they are. | |
c0115606 | 1735 | assign-busses [X86] Always assign all PCI bus |
a9913044 RD |
1736 | numbers ourselves, overriding |
1737 | whatever the firmware may have done. | |
c0115606 | 1738 | usepirqmask [X86] Honor the possible IRQ mask stored |
a9913044 RD |
1739 | in the BIOS $PIR table. This is needed on |
1740 | some systems with broken BIOSes, notably | |
1741 | some HP Pavilion N5400 and Omnibook XE3 | |
1742 | notebooks. This will have no effect if ACPI | |
1743 | IRQ routing is enabled. | |
c0115606 | 1744 | noacpi [X86] Do not use ACPI for IRQ routing |
a9913044 | 1745 | or for PCI scanning. |
c0115606 | 1746 | use_crs [X86] Use _CRS for PCI resource |
62f420f8 | 1747 | allocation. |
a9913044 RD |
1748 | routeirq Do IRQ routing for all PCI devices. |
1749 | This is normally done in pci_enable_device(), | |
1750 | so this option is a temporary workaround | |
1751 | for broken drivers that don't call it. | |
13a6ddb0 YL |
1752 | skip_isa_align [X86] do not align io start addr, so can |
1753 | handle more pci cards | |
a9913044 RD |
1754 | firmware [ARM] Do not re-enumerate the bus but instead |
1755 | just use the configuration from the | |
1756 | bootloader. This is currently used on | |
1757 | IXP2000 systems where the bus has to be | |
1758 | configured a certain way for adjunct CPUs. | |
0637a70a AK |
1759 | noearly [X86] Don't do any early type 1 scanning. |
1760 | This might help on some broken boards which | |
1761 | machine check when some devices' config space | |
1762 | is read. But various workarounds are disabled | |
1763 | and some IOMMU drivers will not work. | |
6b4b78fe MD |
1764 | bfsort Sort PCI devices into breadth-first order. |
1765 | This sorting is done to get a device | |
1766 | order compatible with older (<= 2.4) kernels. | |
1767 | nobfsort Don't sort PCI devices into breadth-first order. | |
4516a618 AN |
1768 | cbiosize=nn[KMG] The fixed amount of bus space which is |
1769 | reserved for the CardBus bridge's IO window. | |
1770 | The default value is 256 bytes. | |
1771 | cbmemsize=nn[KMG] The fixed amount of bus space which is | |
1772 | reserved for the CardBus bridge's memory | |
1773 | window. The default value is 64 megabytes. | |
32a9a682 YS |
1774 | resource_alignment= |
1775 | Format: | |
1776 | [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] | |
1777 | Specifies alignment and device to reassign | |
1778 | aligned memory resources. | |
1779 | If <order of align> is not specified, | |
1780 | PAGE_SIZE is used as alignment. | |
1781 | PCI-PCI bridge can be specified, if resource | |
1782 | windows need to be expanded. | |
6b4b78fe | 1783 | |
e5665a45 CE |
1784 | pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power |
1785 | Management. | |
1786 | off Disable ASPM. | |
1787 | force Enable ASPM even on devices that claim not to support it. | |
1788 | WARNING: Forcing ASPM on may cause system lockups. | |
1789 | ||
1da177e4 LT |
1790 | pcmv= [HW,PCMCIA] BadgePAD 4 |
1791 | ||
1792 | pd. [PARIDE] | |
31c00fc1 | 1793 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
1794 | |
1795 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at | |
1796 | boot time. | |
1797 | Format: { 0 | 1 } | |
1798 | See arch/parisc/kernel/pdc_chassis.c | |
1799 | ||
1800 | pf. [PARIDE] | |
31c00fc1 | 1801 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
1802 | |
1803 | pg. [PARIDE] | |
31c00fc1 | 1804 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
1805 | |
1806 | pirq= [SMP,APIC] Manual mp-table setup | |
71cced6e | 1807 | See Documentation/x86/i386/IO-APIC.txt. |
1da177e4 LT |
1808 | |
1809 | plip= [PPT,NET] Parallel port network link | |
1810 | Format: { parport<nr> | timid | 0 } | |
1811 | See also Documentation/parport.txt. | |
1812 | ||
de32a243 TG |
1813 | pmtmr= [X86] Manual setup of pmtmr I/O Port. |
1814 | Override pmtimer IOPort with a hex value. | |
1815 | e.g. pmtmr=0x508 | |
1816 | ||
97ef062b BH |
1817 | pnp.debug [PNP] |
1818 | Enable PNP debug messages. This depends on the | |
1819 | CONFIG_PNP_DEBUG_MESSAGES option. | |
1820 | ||
1da177e4 LT |
1821 | pnpacpi= [ACPI] |
1822 | { off } | |
1823 | ||
1824 | pnpbios= [ISAPNP] | |
1825 | { on | off | curr | res | no-curr | no-res } | |
1826 | ||
1827 | pnp_reserve_irq= | |
1828 | [ISAPNP] Exclude IRQs for the autoconfiguration | |
1829 | ||
1830 | pnp_reserve_dma= | |
1831 | [ISAPNP] Exclude DMAs for the autoconfiguration | |
1832 | ||
1833 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration | |
a9913044 | 1834 | Ranges are in pairs (I/O port base and size). |
1da177e4 LT |
1835 | |
1836 | pnp_reserve_mem= | |
a9913044 RD |
1837 | [ISAPNP] Exclude memory regions for the |
1838 | autoconfiguration. | |
1da177e4 LT |
1839 | Ranges are in pairs (memory base and size). |
1840 | ||
45807a1d IM |
1841 | print-fatal-signals= |
1842 | [KNL] debug: print fatal signals | |
1843 | print-fatal-signals=1: print segfault info to | |
1844 | the kernel console. | |
1845 | default: off. | |
1846 | ||
e84845c4 RD |
1847 | printk.time= Show timing data prefixed to each printk message line |
1848 | Format: <bool> (1/Y/y=enable, 0/N/n=disable) | |
1849 | ||
0cb55ad2 RD |
1850 | processor.max_cstate= [HW,ACPI] |
1851 | Limit processor to maximum C-state | |
1852 | max_cstate=9 overrides any DMI blacklist limit. | |
1853 | ||
1854 | processor.nocst [HW,ACPI] | |
1855 | Ignore the _CST method to determine C-states, | |
1856 | instead using the legacy FADT method | |
1857 | ||
1da177e4 | 1858 | profile= [KNL] Enable kernel profiling via /proc/profile |
a9913044 RD |
1859 | Format: [schedule,]<number> |
1860 | Param: "schedule" - profile schedule points. | |
1861 | Param: <number> - step/bucket size as a power of 2 for | |
1862 | statistical time based profiling. | |
b3da2a73 MG |
1863 | Param: "sleep" - profile D-state sleeping (millisecs). |
1864 | Requires CONFIG_SCHEDSTATS | |
c0fe2e69 | 1865 | Param: "kvm" - profile VM exits. |
1da177e4 | 1866 | |
1da177e4 LT |
1867 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk |
1868 | before loading. | |
31c00fc1 | 1869 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 1870 | |
a9913044 RD |
1871 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to |
1872 | probe for; one of (bare|imps|exps|lifebook|any). | |
1da177e4 LT |
1873 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports |
1874 | per second. | |
a9913044 RD |
1875 | psmouse.resetafter= [HW,MOUSE] |
1876 | Try to reset the device after so many bad packets | |
1da177e4 LT |
1877 | (0 = never). |
1878 | psmouse.resolution= | |
1879 | [HW,MOUSE] Set desired mouse resolution, in dpi. | |
1880 | psmouse.smartscroll= | |
a9913044 | 1881 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. |
1da177e4 LT |
1882 | 0 = disabled, 1 = enabled (default). |
1883 | ||
1884 | pss= [HW,OSS] Personal Sound System (ECHO ESC614) | |
a9913044 RD |
1885 | Format: |
1886 | <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> | |
1da177e4 LT |
1887 | |
1888 | pt. [PARIDE] | |
31c00fc1 | 1889 | See Documentation/blockdev/paride.txt. |
1da177e4 | 1890 | |
dc8c8587 KS |
1891 | pty.legacy_count= |
1892 | [KNL] Number of legacy pty's. Overwrites compiled-in | |
1893 | default number. | |
1894 | ||
7d2c502f | 1895 | quiet [KNL] Disable most log messages |
a9913044 | 1896 | |
1da177e4 LT |
1897 | r128= [HW,DRM] |
1898 | ||
1899 | raid= [HW,RAID] | |
1900 | See Documentation/md.txt. | |
1901 | ||
a9913044 | 1902 | ramdisk_blocksize= [RAM] |
31c00fc1 | 1903 | See Documentation/blockdev/ramdisk.txt. |
a9913044 | 1904 | |
1da177e4 | 1905 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
31c00fc1 | 1906 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 1907 | |
24aaef8d RD |
1908 | rcupdate.blimit= [KNL,BOOT] |
1909 | Set maximum number of finished RCU callbacks to process | |
1910 | in one batch. | |
21a1ea9e | 1911 | |
24aaef8d RD |
1912 | rcupdate.qhimark= [KNL,BOOT] |
1913 | Set threshold of queued | |
21a1ea9e DS |
1914 | RCU callbacks over which batch limiting is disabled. |
1915 | ||
24aaef8d RD |
1916 | rcupdate.qlowmark= [KNL,BOOT] |
1917 | Set threshold of queued RCU callbacks below which | |
1918 | batch limiting is re-enabled. | |
21a1ea9e | 1919 | |
ffdfc409 OJ |
1920 | rdinit= [KNL] |
1921 | Format: <full_path> | |
1922 | Run specified binary instead of /init from the ramdisk, | |
1923 | used for early userspace startup. See initrd. | |
1924 | ||
cd4f0ef7 | 1925 | reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode |
1da177e4 | 1926 | Format: <reboot_mode>[,<reboot_mode2>[,...]] |
ecb08d81 | 1927 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c |
1da177e4 | 1928 | |
46b6d94e PJ |
1929 | relax_domain_level= |
1930 | [KNL, SMP] Set scheduler's default relax_domain_level. | |
21acb9ca | 1931 | See Documentation/cgroups/cpusets.txt. |
46b6d94e | 1932 | |
1da177e4 LT |
1933 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area |
1934 | ||
cd4f0ef7 | 1935 | reservetop= [X86-32] |
461a9aff ZA |
1936 | Format: nn[KMG] |
1937 | Reserves a hole at the top of the kernel virtual | |
1938 | address space. | |
1939 | ||
7e96287d VG |
1940 | reset_devices [KNL] Force drivers to reset the underlying device |
1941 | during initialization. | |
1942 | ||
a9913044 RD |
1943 | resume= [SWSUSP] |
1944 | Specify the partition device for software suspend | |
1da177e4 | 1945 | |
ecbd0da1 RW |
1946 | resume_offset= [SWSUSP] |
1947 | Specify the offset from the beginning of the partition | |
1948 | given by "resume=" at which the swap header is located, | |
1949 | in <PAGE_SIZE> units (needed only for swap files). | |
1950 | See Documentation/power/swsusp-and-swap-files.txt | |
1951 | ||
0a7b35cb MN |
1952 | retain_initrd [RAM] Keep initrd memory after extraction |
1953 | ||
1da177e4 LT |
1954 | rhash_entries= [KNL,NET] |
1955 | Set number of hash buckets for route cache | |
1956 | ||
1957 | riscom8= [HW,SERIAL] | |
1958 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] | |
1959 | ||
1960 | ro [KNL] Mount root device read-only on boot | |
1961 | ||
1962 | root= [KNL] Root filesystem | |
1963 | ||
1964 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to | |
1965 | mount the root filesystem | |
1966 | ||
1967 | rootflags= [KNL] Set root filesystem mount option string | |
1968 | ||
1969 | rootfstype= [KNL] Set root filesystem type | |
1970 | ||
cc1ed754 PO |
1971 | rootwait [KNL] Wait (indefinitely) for root device to show up. |
1972 | Useful for devices that are detected asynchronously | |
1973 | (e.g. USB and MMC devices). | |
1974 | ||
20510f2f JM |
1975 | root_plug.vendor_id= |
1976 | [ROOTPLUG] Override the default vendor ID | |
1977 | ||
1978 | root_plug.product_id= | |
1979 | [ROOTPLUG] Override the default product ID | |
1980 | ||
1981 | root_plug.debug= | |
1982 | [ROOTPLUG] Enable debugging output | |
1983 | ||
1da177e4 LT |
1984 | rw [KNL] Mount root device read-write on boot |
1985 | ||
1986 | S [KNL] Run init in single mode | |
1987 | ||
1988 | sa1100ir [NET] | |
1989 | See drivers/net/irda/sa1100_ir.c. | |
1990 | ||
1da177e4 | 1991 | sbni= [NET] Granch SBNI12 leased line adapter |
a9913044 | 1992 | |
1da177e4 LT |
1993 | sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver |
1994 | Format: <io>[,<timeout>[,<isapnp>]] | |
1995 | ||
1996 | scsi_debug_*= [SCSI] | |
1997 | See drivers/scsi/scsi_debug.c. | |
1998 | ||
1999 | scsi_default_dev_flags= | |
2000 | [SCSI] SCSI default device flags | |
2001 | Format: <integer> | |
2002 | ||
2003 | scsi_dev_flags= [SCSI] Black/white list entry for vendor and model | |
2004 | Format: <vendor>:<model>:<flags> | |
2005 | (flags are integer value) | |
2006 | ||
6af6632a RD |
2007 | scsi_logging_level= [SCSI] a bit mask of logging levels |
2008 | See drivers/scsi/scsi_logging.h for bits. Also | |
2009 | settable via sysctl at dev.scsi.logging_level | |
2010 | (/proc/sys/dev/scsi/logging_level). | |
2011 | There is also a nice 'scsi_logging_level' script in the | |
2012 | S390-tools package, available for download at | |
2013 | http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html | |
1da177e4 | 2014 | |
3e082a91 MW |
2015 | scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are |
2016 | discovered. async scans them in kernel threads, | |
2017 | allowing boot to proceed. none ignores them, expecting | |
2018 | user space to do the scan. | |
2019 | ||
0cb55ad2 RD |
2020 | security= [SECURITY] Choose a security module to enable at boot. |
2021 | If this boot parameter is not specified, only the first | |
2022 | security module asking for security registration will be | |
2023 | loaded. An invalid security module name will be treated | |
2024 | as if no module has been chosen. | |
2025 | ||
2026 | selinux= [SELINUX] Disable or enable SELinux at boot time. | |
1da177e4 LT |
2027 | Format: { "0" | "1" } |
2028 | See security/selinux/Kconfig help text. | |
2029 | 0 -- disable. | |
2030 | 1 -- enable. | |
2031 | Default value is set via kernel config option. | |
2032 | If enabled at boot time, /selinux/disable can be used | |
2033 | later to disable prior to initial policy load. | |
2034 | ||
cd4f0ef7 | 2035 | serialnumber [BUGS=X86-32] |
1da177e4 | 2036 | |
1da177e4 LT |
2037 | shapers= [NET] |
2038 | Maximal number of shapers. | |
a9913044 | 2039 | |
b05f78f5 YL |
2040 | show_msr= [x86] show boot-time MSR settings |
2041 | Format: { <integer> } | |
2042 | Show boot-time (BIOS-initialized) MSR settings. | |
2043 | The parameter means the number of CPUs to show, | |
2044 | for example 1 means boot CPU only. | |
2045 | ||
1da177e4 LT |
2046 | sim710= [SCSI,HW] |
2047 | See header of drivers/scsi/sim710.c. | |
2048 | ||
2049 | simeth= [IA-64] | |
2050 | simscsi= | |
a9913044 | 2051 | |
1da177e4 LT |
2052 | slram= [HW,MTD] |
2053 | ||
f0630fff CL |
2054 | slub_debug[=options[,slabs]] [MM, SLUB] |
2055 | Enabling slub_debug allows one to determine the | |
2056 | culprit if slab objects become corrupted. Enabling | |
2057 | slub_debug can create guard zones around objects and | |
2058 | may poison objects when not in use. Also tracks the | |
2059 | last alloc / free. For more information see | |
2060 | Documentation/vm/slub.txt. | |
c1aee215 CL |
2061 | |
2062 | slub_max_order= [MM, SLUB] | |
f0630fff CL |
2063 | Determines the maximum allowed order for slabs. |
2064 | A high setting may cause OOMs due to memory | |
2065 | fragmentation. For more information see | |
2066 | Documentation/vm/slub.txt. | |
c1aee215 CL |
2067 | |
2068 | slub_min_objects= [MM, SLUB] | |
f0630fff CL |
2069 | The minimum number of objects per slab. SLUB will |
2070 | increase the slab order up to slub_max_order to | |
2071 | generate a sufficiently large slab able to contain | |
2072 | the number of objects indicated. The higher the number | |
2073 | of objects the smaller the overhead of tracking slabs | |
2074 | and the less frequently locks need to be acquired. | |
c1aee215 CL |
2075 | For more information see Documentation/vm/slub.txt. |
2076 | ||
2077 | slub_min_order= [MM, SLUB] | |
2078 | Determines the mininum page order for slabs. Must be | |
f0630fff | 2079 | lower than slub_max_order. |
c1aee215 CL |
2080 | For more information see Documentation/vm/slub.txt. |
2081 | ||
2082 | slub_nomerge [MM, SLUB] | |
f0630fff | 2083 | Disable merging of slabs with similar size. May be |
c1aee215 | 2084 | necessary if there is some reason to distinguish |
f0630fff CL |
2085 | allocs to different slabs. Debug options disable |
2086 | merging on their own. | |
c1aee215 CL |
2087 | For more information see Documentation/vm/slub.txt. |
2088 | ||
1da177e4 LT |
2089 | smart2= [HW] |
2090 | Format: <io1>[,<io2>[,...,<io8>]] | |
2091 | ||
cd4f0ef7 | 2092 | smp-alt-once [X86-32,SMP] On a hotplug CPU system, only |
b7fb4af0 JF |
2093 | attempt to substitute SMP alternatives once at boot. |
2094 | ||
d0d4f69b BH |
2095 | smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices |
2096 | smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port | |
2097 | smsc-ircc2.ircc_sir= [HW] SIR base I/O port | |
2098 | smsc-ircc2.ircc_fir= [HW] FIR base I/O port | |
2099 | smsc-ircc2.ircc_irq= [HW] IRQ line | |
2100 | smsc-ircc2.ircc_dma= [HW] DMA channel | |
2101 | smsc-ircc2.ircc_transceiver= [HW] Transceiver type: | |
2102 | 0: Toshiba Satellite 1800 (GP data pin select) | |
2103 | 1: Fast pin select (default) | |
2104 | 2: ATC IRMode | |
2105 | ||
1da177e4 LT |
2106 | snd-ad1816a= [HW,ALSA] |
2107 | ||
2108 | snd-ad1848= [HW,ALSA] | |
2109 | ||
2110 | snd-ali5451= [HW,ALSA] | |
2111 | ||
2112 | snd-als100= [HW,ALSA] | |
2113 | ||
2114 | snd-als4000= [HW,ALSA] | |
2115 | ||
2116 | snd-azt2320= [HW,ALSA] | |
2117 | ||
2118 | snd-cmi8330= [HW,ALSA] | |
2119 | ||
2120 | snd-cmipci= [HW,ALSA] | |
2121 | ||
2122 | snd-cs4231= [HW,ALSA] | |
2123 | ||
2124 | snd-cs4232= [HW,ALSA] | |
2125 | ||
2126 | snd-cs4236= [HW,ALSA] | |
2127 | ||
2128 | snd-cs4281= [HW,ALSA] | |
2129 | ||
2130 | snd-cs46xx= [HW,ALSA] | |
2131 | ||
2132 | snd-dt019x= [HW,ALSA] | |
2133 | ||
2134 | snd-dummy= [HW,ALSA] | |
2135 | ||
2136 | snd-emu10k1= [HW,ALSA] | |
2137 | ||
2138 | snd-ens1370= [HW,ALSA] | |
2139 | ||
2140 | snd-ens1371= [HW,ALSA] | |
2141 | ||
2142 | snd-es968= [HW,ALSA] | |
2143 | ||
2144 | snd-es1688= [HW,ALSA] | |
2145 | ||
2146 | snd-es18xx= [HW,ALSA] | |
2147 | ||
2148 | snd-es1938= [HW,ALSA] | |
2149 | ||
2150 | snd-es1968= [HW,ALSA] | |
2151 | ||
2152 | snd-fm801= [HW,ALSA] | |
2153 | ||
2154 | snd-gusclassic= [HW,ALSA] | |
2155 | ||
2156 | snd-gusextreme= [HW,ALSA] | |
2157 | ||
2158 | snd-gusmax= [HW,ALSA] | |
2159 | ||
2160 | snd-hdsp= [HW,ALSA] | |
2161 | ||
2162 | snd-ice1712= [HW,ALSA] | |
2163 | ||
2164 | snd-intel8x0= [HW,ALSA] | |
2165 | ||
2166 | snd-interwave= [HW,ALSA] | |
2167 | ||
2168 | snd-interwave-stb= | |
2169 | [HW,ALSA] | |
2170 | ||
2171 | snd-korg1212= [HW,ALSA] | |
2172 | ||
2173 | snd-maestro3= [HW,ALSA] | |
2174 | ||
2175 | snd-mpu401= [HW,ALSA] | |
2176 | ||
2177 | snd-mtpav= [HW,ALSA] | |
2178 | ||
2179 | snd-nm256= [HW,ALSA] | |
2180 | ||
2181 | snd-opl3sa2= [HW,ALSA] | |
2182 | ||
2183 | snd-opti92x-ad1848= | |
2184 | [HW,ALSA] | |
2185 | ||
2186 | snd-opti92x-cs4231= | |
2187 | [HW,ALSA] | |
2188 | ||
2189 | snd-opti93x= [HW,ALSA] | |
2190 | ||
2191 | snd-pmac= [HW,ALSA] | |
2192 | ||
2193 | snd-rme32= [HW,ALSA] | |
2194 | ||
2195 | snd-rme96= [HW,ALSA] | |
2196 | ||
2197 | snd-rme9652= [HW,ALSA] | |
2198 | ||
2199 | snd-sb8= [HW,ALSA] | |
2200 | ||
2201 | snd-sb16= [HW,ALSA] | |
2202 | ||
2203 | snd-sbawe= [HW,ALSA] | |
2204 | ||
2205 | snd-serial= [HW,ALSA] | |
2206 | ||
2207 | snd-sgalaxy= [HW,ALSA] | |
2208 | ||
2209 | snd-sonicvibes= [HW,ALSA] | |
2210 | ||
2211 | snd-sun-amd7930= | |
2212 | [HW,ALSA] | |
2213 | ||
2214 | snd-sun-cs4231= [HW,ALSA] | |
2215 | ||
2216 | snd-trident= [HW,ALSA] | |
2217 | ||
2218 | snd-usb-audio= [HW,ALSA,USB] | |
2219 | ||
2220 | snd-via82xx= [HW,ALSA] | |
2221 | ||
2222 | snd-virmidi= [HW,ALSA] | |
2223 | ||
2224 | snd-wavefront= [HW,ALSA] | |
2225 | ||
2226 | snd-ymfpci= [HW,ALSA] | |
a9913044 | 2227 | |
9c44bc03 IM |
2228 | softlockup_panic= |
2229 | [KNL] Should the soft-lockup detector generate panics. | |
2230 | ||
1da177e4 LT |
2231 | sonypi.*= [HW] Sony Programmable I/O Control Device driver |
2232 | See Documentation/sonypi.txt | |
2233 | ||
2234 | specialix= [HW,SERIAL] Specialix multi-serial port adapter | |
31c00fc1 | 2235 | See Documentation/serial/specialix.txt. |
1da177e4 LT |
2236 | |
2237 | spia_io_base= [HW,MTD] | |
2238 | spia_fio_base= | |
2239 | spia_pedr= | |
2240 | spia_peddr= | |
2241 | ||
2242 | sscape= [HW,OSS] | |
2243 | Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq> | |
a9913044 | 2244 | |
1da177e4 LT |
2245 | st= [HW,SCSI] SCSI tape parameters (buffers, etc.) |
2246 | See Documentation/scsi/st.txt. | |
2247 | ||
f38f1d2a SR |
2248 | stacktrace [FTRACE] |
2249 | Enabled the stack tracer on boot up. | |
2250 | ||
1da177e4 LT |
2251 | sti= [PARISC,HW] |
2252 | Format: <num> | |
2253 | Set the STI (builtin display/keyboard on the HP-PARISC | |
2254 | machines) console (graphic card) which should be used | |
2255 | as the initial boot-console. | |
2256 | See also comment in drivers/video/console/sticore.c. | |
2257 | ||
2258 | sti_font= [HW] | |
2259 | See comment in drivers/video/console/sticore.c. | |
2260 | ||
2261 | stifb= [HW] | |
2262 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] | |
2263 | ||
42a7fc4a GB |
2264 | sunrpc.pool_mode= |
2265 | [NFS] | |
2266 | Control how the NFS server code allocates CPUs to | |
2267 | service thread pools. Depending on how many NICs | |
2268 | you have and where their interrupts are bound, this | |
2269 | option will affect which CPUs will do NFS serving. | |
2270 | Note: this parameter cannot be changed while the | |
2271 | NFS server is running. | |
2272 | ||
2273 | auto the server chooses an appropriate mode | |
2274 | automatically using heuristics | |
2275 | global a single global pool contains all CPUs | |
2276 | percpu one pool for each CPU | |
2277 | pernode one pool for each NUMA node (equivalent | |
2278 | to global on non-NUMA machines) | |
2279 | ||
1da177e4 | 2280 | swiotlb= [IA-64] Number of I/O TLB slabs |
a9913044 | 2281 | |
1da177e4 LT |
2282 | switches= [HW,M68k] |
2283 | ||
2284 | sym53c416= [HW,SCSI] | |
2285 | See header of drivers/scsi/sym53c416.c. | |
2286 | ||
5d6f647f IM |
2287 | sysrq_always_enabled |
2288 | [KNL] | |
2289 | Ignore sysrq setting - this boot parameter will | |
2290 | neutralize any effect of /proc/sys/kernel/sysrq. | |
2291 | Useful for debugging. | |
2292 | ||
1da177e4 LT |
2293 | t128= [HW,SCSI] |
2294 | See header of drivers/scsi/t128.c. | |
2295 | ||
2296 | tdfx= [HW,DRM] | |
2297 | ||
77437fd4 DB |
2298 | test_suspend= [SUSPEND] |
2299 | Specify "mem" (for Suspend-to-RAM) or "standby" (for | |
2300 | standby suspend) as the system sleep state to briefly | |
2301 | enter during system startup. The system is woken from | |
2302 | this state using a wakeup-capable RTC alarm. | |
2303 | ||
1da177e4 LT |
2304 | thash_entries= [KNL,NET] |
2305 | Set number of hash buckets for TCP connection | |
2306 | ||
f8707ec9 LB |
2307 | thermal.act= [HW,ACPI] |
2308 | -1: disable all active trip points in all thermal zones | |
2309 | <degrees C>: override all lowest active trip points | |
2310 | ||
c52a7419 LB |
2311 | thermal.crt= [HW,ACPI] |
2312 | -1: disable all critical trip points in all thermal zones | |
22a94d79 | 2313 | <degrees C>: override all critical trip points |
c52a7419 | 2314 | |
f5487145 LB |
2315 | thermal.nocrt= [HW,ACPI] |
2316 | Set to disable actions on ACPI thermal zone | |
2317 | critical and hot trip points. | |
2318 | ||
72b33ef8 LB |
2319 | thermal.off= [HW,ACPI] |
2320 | 1: disable ACPI thermal control | |
2321 | ||
a70cdc52 LB |
2322 | thermal.psv= [HW,ACPI] |
2323 | -1: disable all passive trip points | |
ada9cfdd RD |
2324 | <degrees C>: override all passive trip points to this |
2325 | value | |
a70cdc52 | 2326 | |
730ff34d LB |
2327 | thermal.tzp= [HW,ACPI] |
2328 | Specify global default ACPI thermal zone polling rate | |
2329 | <deci-seconds>: poll all this frequency | |
2330 | 0: no polling (default) | |
2331 | ||
1da177e4 LT |
2332 | tmscsim= [HW,SCSI] |
2333 | See comment before function dc390_setup() in | |
2334 | drivers/scsi/tmscsim.c. | |
2335 | ||
2b1a61f0 HC |
2336 | topology= [S390] |
2337 | Format: {off | on} | |
2338 | Specify if the kernel should make use of the cpu | |
2339 | topology informations if the hardware supports these. | |
2340 | The scheduler will make use of these informations and | |
2341 | e.g. base its process migration decisions on it. | |
2342 | Default is off. | |
2343 | ||
1da177e4 LT |
2344 | tp720= [HW,PS2] |
2345 | ||
631595fb KM |
2346 | trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size. |
2347 | ||
1da177e4 | 2348 | trix= [HW,OSS] MediaTrix AudioTrix Pro |
a9913044 RD |
2349 | Format: |
2350 | <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> | |
2351 | ||
395628ef AK |
2352 | tsc= Disable clocksource-must-verify flag for TSC. |
2353 | Format: <string> | |
2354 | [x86] reliable: mark tsc clocksource as reliable, this | |
2355 | disables clocksource verification at runtime. | |
2356 | Used to enable high-resolution timer mode on older | |
2357 | hardware, and in virtualized environment. | |
2358 | ||
a9913044 RD |
2359 | turbografx.map[2|3]= [HW,JOY] |
2360 | TurboGraFX parallel port interface | |
2361 | Format: | |
2362 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> | |
1da177e4 LT |
2363 | See also Documentation/input/joystick-parport.txt |
2364 | ||
2365 | u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter | |
2366 | See header of drivers/scsi/u14-34f.c. | |
2367 | ||
2368 | uart401= [HW,OSS] | |
2369 | Format: <io>,<irq> | |
2370 | ||
2371 | uart6850= [HW,OSS] | |
2372 | Format: <io>,<irq> | |
2373 | ||
5f8364b7 AS |
2374 | uhci-hcd.ignore_oc= |
2375 | [USB] Ignore overcurrent events (default N). | |
2376 | Some badly-designed motherboards generate lots of | |
2377 | bogus events, for ports that aren't wired to | |
2378 | anything. Set this parameter to avoid log spamming. | |
2379 | Note that genuine overcurrent events won't be | |
2380 | reported either. | |
2381 | ||
e3a61b0a SA |
2382 | unknown_nmi_panic |
2383 | [X86-32,X86-64] | |
2384 | Set unknown_nmi_panic=1 early on boot. | |
2385 | ||
b5e795f8 AS |
2386 | usbcore.autosuspend= |
2387 | [USB] The autosuspend time delay (in seconds) used | |
2388 | for newly-detected USB devices (default 2). This | |
2389 | is the time required before an idle device will be | |
2390 | autosuspended. Devices for which the delay is set | |
eaafbc3a | 2391 | to a negative value won't be autosuspended at all. |
b5e795f8 | 2392 | |
fd7c519d JK |
2393 | usbcore.usbfs_snoop= |
2394 | [USB] Set to log all usbfs traffic (default 0 = off). | |
2395 | ||
2396 | usbcore.blinkenlights= | |
2397 | [USB] Set to cycle leds on hubs (default 0 = off). | |
2398 | ||
2399 | usbcore.old_scheme_first= | |
2400 | [USB] Start with the old device initialization | |
2401 | scheme (default 0 = off). | |
2402 | ||
2403 | usbcore.use_both_schemes= | |
2404 | [USB] Try the other device initialization scheme | |
2405 | if the first one fails (default 1 = enabled). | |
2406 | ||
2407 | usbcore.initial_descriptor_timeout= | |
2408 | [USB] Specifies timeout for the initial 64-byte | |
2409 | USB_REQ_GET_DESCRIPTOR request in milliseconds | |
2410 | (default 5000 = 5.0 seconds). | |
2411 | ||
1da177e4 LT |
2412 | usbhid.mousepoll= |
2413 | [USBHID] The interval which mice are to be polled at. | |
a9913044 | 2414 | |
d4f373e5 AS |
2415 | usb-storage.delay_use= |
2416 | [UMS] The delay in seconds before a new device is | |
2417 | scanned for Logical Units (default 5). | |
2418 | ||
2419 | usb-storage.quirks= | |
2420 | [UMS] A list of quirks entries to supplement or | |
2421 | override the built-in unusual_devs list. List | |
2422 | entries are separated by commas. Each entry has | |
2423 | the form VID:PID:Flags where VID and PID are Vendor | |
2424 | and Product ID values (4-digit hex numbers) and | |
2425 | Flags is a set of characters, each corresponding | |
2426 | to a common usb-storage quirk flag as follows: | |
c838ea46 AS |
2427 | a = SANE_SENSE (collect more than 18 bytes |
2428 | of sense data); | |
d4f373e5 AS |
2429 | c = FIX_CAPACITY (decrease the reported |
2430 | device capacity by one sector); | |
c838ea46 AS |
2431 | h = CAPACITY_HEURISTICS (decrease the |
2432 | reported device capacity by one | |
2433 | sector if the number is odd); | |
d4f373e5 AS |
2434 | i = IGNORE_DEVICE (don't bind to this |
2435 | device); | |
2436 | l = NOT_LOCKABLE (don't try to lock and | |
2437 | unlock ejectable media); | |
2438 | m = MAX_SECTORS_64 (don't transfer more | |
2439 | than 64 sectors = 32 KB at a time); | |
c838ea46 AS |
2440 | o = CAPACITY_OK (accept the capacity |
2441 | reported by the device); | |
d4f373e5 AS |
2442 | r = IGNORE_RESIDUE (the device reports |
2443 | bogus residue values); | |
2444 | s = SINGLE_LUN (the device has only one | |
2445 | Logical Unit); | |
2446 | w = NO_WP_DETECT (don't test whether the | |
2447 | medium is write-protected). | |
2448 | Example: quirks=0419:aaf5:rl,0421:0433:rc | |
2449 | ||
cd4f0ef7 | 2450 | vdso= [X86-32,SH,x86-64] |
1dbf527c | 2451 | vdso=2: enable compat VDSO (default with COMPAT_VDSO) |
e6e5494c IM |
2452 | vdso=1: enable VDSO (default) |
2453 | vdso=0: disable VDSO mapping | |
2454 | ||
af65d648 RM |
2455 | vdso32= [X86-32,X86-64] |
2456 | vdso32=2: enable compat VDSO (default with COMPAT_VDSO) | |
2457 | vdso32=1: enable 32-bit VDSO (default) | |
2458 | vdso32=0: disable 32-bit VDSO mapping | |
2459 | ||
d080d397 YI |
2460 | vector= [IA-64,SMP] |
2461 | vector=percpu: enable percpu vector domain | |
2462 | ||
1da177e4 LT |
2463 | video= [FB] Frame buffer configuration |
2464 | See Documentation/fb/modedb.txt. | |
2465 | ||
cd4f0ef7 | 2466 | vga= [BOOT,X86-32] Select a particular video mode |
954a8b81 | 2467 | See Documentation/x86/boot.txt and |
a9913044 | 2468 | Documentation/svga.txt. |
1da177e4 LT |
2469 | Use vga=ask for menu. |
2470 | This is actually a boot loader parameter; the value is | |
2471 | passed to the kernel using a special protocol. | |
2472 | ||
a9913044 | 2473 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact |
1da177e4 LT |
2474 | size of <nn>. This can be used to increase the |
2475 | minimum size (128MB on x86). It can also be used to | |
2476 | decrease the size and leave more room for directly | |
2477 | mapped kernel RAM. | |
2478 | ||
585c3047 PO |
2479 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. |
2480 | Format: <command> | |
1da177e4 | 2481 | |
585c3047 PO |
2482 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. |
2483 | Format: <command> | |
2484 | ||
2485 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. | |
2486 | Format: <command> | |
a9913044 | 2487 | |
0cb55ad2 RD |
2488 | vt.default_blu= [VT] |
2489 | Format: <blue0>,<blue1>,<blue2>,...,<blue15> | |
2490 | Change the default blue palette of the console. | |
2491 | This is a 16-member array composed of values | |
2492 | ranging from 0-255. | |
2493 | ||
2494 | vt.default_grn= [VT] | |
2495 | Format: <green0>,<green1>,<green2>,...,<green15> | |
2496 | Change the default green palette of the console. | |
2497 | This is a 16-member array composed of values | |
2498 | ranging from 0-255. | |
2499 | ||
2500 | vt.default_red= [VT] | |
2501 | Format: <red0>,<red1>,<red2>,...,<red15> | |
2502 | Change the default red palette of the console. | |
2503 | This is a 16-member array composed of values | |
2504 | ranging from 0-255. | |
2505 | ||
2506 | vt.default_utf8= | |
2507 | [VT] | |
2508 | Format=<0|1> | |
2509 | Set system-wide default UTF-8 mode for all tty's. | |
2510 | Default is 1, i.e. UTF-8 mode is enabled for all | |
2511 | newly opened terminals. | |
2512 | ||
1da177e4 LT |
2513 | waveartist= [HW,OSS] |
2514 | Format: <io>,<irq>,<dma>,<dma2> | |
a9913044 | 2515 | |
1da177e4 LT |
2516 | wd33c93= [HW,SCSI] |
2517 | See header of drivers/scsi/wd33c93.c. | |
2518 | ||
2519 | wd7000= [HW,SCSI] | |
2520 | See header of drivers/scsi/wd7000.c. | |
2521 | ||
2522 | wdt= [WDT] Watchdog | |
8dfe9c21 | 2523 | See Documentation/watchdog/wdt.txt. |
1da177e4 | 2524 | |
0cb55ad2 RD |
2525 | x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of |
2526 | default x2apic cluster mode on platforms | |
2527 | supporting x2apic. | |
2528 | ||
1da177e4 LT |
2529 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. |
2530 | xd_geo= See header of drivers/block/xd.c. | |
2531 | ||
2532 | xirc2ps_cs= [NET,PCMCIA] | |
a9913044 RD |
2533 | Format: |
2534 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] | |
1da177e4 | 2535 | |
a9913044 | 2536 | ______________________________________________________________________ |
1da177e4 LT |
2537 | |
2538 | TODO: | |
2539 | ||
2540 | Add documentation for ALSA options. | |
2541 | Add more DRM drivers. |