1 Kernel Parameters 2 ~~~~~~~~~~~~~~~~~ 3 4The 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 7case insensitive manner), and with descriptions where known. 8 9Module parameters for loadable modules are specified only as the 10parameter name with optional '=' and value as appropriate, such as: 11 12 modprobe usbcore blinkenlights=1 13 14Module parameters for modules that are built into the kernel image 15are 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 20This document may not be entirely up to date and comprehensive. The command 21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable 22module. Loadable modules, after being loaded into the running kernel, also 23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these 24parameters may be changed at runtime by the command 25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". 26 27The parameters listed below are only valid if certain kernel build options were 28enabled and if respective hardware is present. The text in square brackets at 29the beginning of each description states the restrictions within which a 30parameter is applicable: 31 32 ACPI ACPI support is enabled. 33 ALSA ALSA sound support is enabled. 34 APIC APIC support is enabled. 35 APM Advanced Power Management support is enabled. 36 AX25 Appropriate AX.25 support is enabled. 37 CD Appropriate CD support is enabled. 38 DRM Direct Rendering Management support is enabled. 39 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled 40 EFI EFI Partitioning (GPT) is enabled 41 EIDE EIDE/ATAPI support is enabled. 42 FB The frame buffer device is enabled. 43 HW Appropriate hardware is enabled. 44 IA-32 IA-32 aka i386 architecture is enabled. 45 IA-64 IA-64 architecture is enabled. 46 IOSCHED More than one I/O scheduler is enabled. 47 IP_PNP IP DHCP, BOOTP, or RARP is enabled. 48 ISAPNP ISA PnP code is enabled. 49 ISDN Appropriate ISDN support is enabled. 50 JOY Appropriate joystick support is enabled. 51 LIBATA Libata driver is enabled 52 LP Printer support is enabled. 53 LOOP Loopback device support is enabled. 54 M68k M68k architecture is enabled. 55 These options have more detailed description inside of 56 Documentation/m68k/kernel-options.txt. 57 MCA MCA bus support is enabled. 58 MDA MDA console support is enabled. 59 MOUSE Appropriate mouse support is enabled. 60 MSI Message Signaled Interrupts (PCI). 61 MTD MTD support is enabled. 62 NET Appropriate network support is enabled. 63 NUMA NUMA support is enabled. 64 GENERIC_TIME The generic timeofday code is enabled. 65 NFS Appropriate NFS support is enabled. 66 OSS OSS sound support is enabled. 67 PV_OPS A paravirtualized kernel 68 PARIDE The ParIDE subsystem is enabled. 69 PARISC The PA-RISC architecture is enabled. 70 PCI PCI bus support is enabled. 71 PCMCIA The PCMCIA subsystem is enabled. 72 PNP Plug & Play support is enabled. 73 PPC PowerPC architecture is enabled. 74 PPT Parallel port support is enabled. 75 PS2 Appropriate PS/2 support is enabled. 76 RAM RAM disk support is enabled. 77 S390 S390 architecture is enabled. 78 SCSI Appropriate SCSI support is enabled. 79 A lot of drivers has their options described inside of 80 Documentation/scsi/. 81 SELINUX SELinux support is enabled. 82 SERIAL Serial support is enabled. 83 SH SuperH architecture is enabled. 84 SMP The kernel is an SMP kernel. 85 SPARC Sparc architecture is enabled. 86 SWSUSP Software suspend is enabled. 87 TS Appropriate touchscreen support is enabled. 88 USB USB support is enabled. 89 USBHID USB Human Interface Device support is enabled. 90 V4L Video For Linux support is enabled. 91 VGA The VGA console has been enabled. 92 VT Virtual terminal support is enabled. 93 WDT Watchdog support is enabled. 94 XT IBM PC/XT MFM hard disk support is enabled. 95 X86-64 X86-64 architecture is enabled. 96 More X86-64 boot options can be found in 97 Documentation/x86_64/boot-options.txt . 98 99In addition, the following text indicates that the option: 100 101 BUGS= Relates to possible processor bugs on the said processor. 102 KNL Is a kernel start-up parameter. 103 BOOT Is a boot loader parameter. 104 105Parameters denoted with BOOT are actually interpreted by the boot 106loader, and have no meaning to the kernel directly. 107Do not modify the syntax of boot loader parameters without extreme 108need or coordination with <Documentation/i386/boot.txt>. 109 110There are also arch-specific kernel-parameters not documented here. 111See for example <Documentation/x86_64/boot-options.txt>. 112 113Note that ALL kernel parameters listed below are CASE SENSITIVE, and that 114a trailing = on the name of any parameter states that that parameter will 115be entered as an environment variable, whereas its absence indicates that 116it will appear as a kernel argument readable via /proc/cmdline by programs 117running once the system is up. 118 119The number of kernel parameters is not limited, but the length of the 120complete command line (parameters including spaces etc.) is limited to 121a fixed number of characters. This limit depends on the architecture 122and is between 256 and 4096 characters. It is defined in the file 123./include/asm/setup.h as COMMAND_LINE_SIZE. 124 125 126 53c7xx= [HW,SCSI] Amiga SCSI controllers 127 See header of drivers/scsi/53c7xx.c. 128 See also Documentation/scsi/ncr53c7xx.txt. 129 130 acpi= [HW,ACPI,X86-64,i386] 131 Advanced Configuration and Power Interface 132 Format: { force | off | ht | strict | noirq } 133 force -- enable ACPI if default was off 134 off -- disable ACPI if default was on 135 noirq -- do not use ACPI for IRQ routing 136 ht -- run only enough ACPI to enable Hyper Threading 137 strict -- Be less tolerant of platforms that are not 138 strictly ACPI specification compliant. 139 140 See also Documentation/pm.txt, pci=noacpi 141 142 acpi_apic_instance= [ACPI, IOAPIC] 143 Format: <int> 144 2: use 2nd APIC table, if available 145 1,0: use 1st APIC table 146 default: 0 147 148 acpi_sleep= [HW,ACPI] Sleep options 149 Format: { s3_bios, s3_mode } 150 See Documentation/power/video.txt 151 152 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode 153 Format: { level | edge | high | low } 154 155 acpi_irq_balance [HW,ACPI] 156 ACPI will balance active IRQs 157 default in APIC mode 158 159 acpi_irq_nobalance [HW,ACPI] 160 ACPI will not move active IRQs (default) 161 default in PIC mode 162 163 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for 164 use by PCI 165 Format: <irq>,<irq>... 166 167 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA 168 Format: <irq>,<irq>... 169 170 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS 171 Format: To spoof as Windows 98: ="Microsoft Windows" 172 173 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings 174 acpi_osi="string1" # add string1 -- only one string 175 acpi_osi="!string2" # remove built-in string2 176 acpi_osi= # disable all strings 177 178 acpi_serialize [HW,ACPI] force serialization of AML methods 179 180 acpi_skip_timer_override [HW,ACPI] 181 Recognize and ignore IRQ0/pin2 Interrupt Override. 182 For broken nForce2 BIOS resulting in XT-PIC timer. 183 acpi_use_timer_override [HW,ACPI} 184 Use timer override. For some broken Nvidia NF5 boards 185 that require a timer override, but don't have 186 HPET 187 188 acpi.debug_layer= [HW,ACPI] 189 Format: <int> 190 Each bit of the <int> indicates an ACPI debug layer, 191 1: enable, 0: disable. It is useful for boot time 192 debugging. After system has booted up, it can be set 193 via /sys/module/acpi/parameters/debug_layer. 194 CONFIG_ACPI_DEBUG must be enabled for this to produce any output. 195 Available bits (add the numbers together) to enable debug output 196 for specific parts of the ACPI subsystem: 197 0x01 utilities 0x02 hardware 0x04 events 0x08 tables 198 0x10 namespace 0x20 parser 0x40 dispatcher 199 0x80 executer 0x100 resources 0x200 acpica debugger 200 0x400 os services 0x800 acpica disassembler. 201 The number can be in decimal or prefixed with 0x in hex. 202 Warning: Many of these options can produce a lot of 203 output and make your system unusable. Be very careful. 204 205 acpi.debug_level= [HW,ACPI] 206 Format: <int> 207 Each bit of the <int> indicates an ACPI debug level, 208 1: enable, 0: disable. It is useful for boot time 209 debugging. After system has booted up, it can be set 210 via /sys/module/acpi/parameters/debug_level. 211 CONFIG_ACPI_DEBUG must be enabled for this to produce any output. 212 Available bits (add the numbers together) to enable different 213 debug output levels of the ACPI subsystem: 214 0x01 error 0x02 warn 0x04 init 0x08 debug object 215 0x10 info 0x20 init names 0x40 parse 0x80 load 216 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region 217 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects 218 0x10000 resources 0x20000 user requests 0x40000 package. 219 The number can be in decimal or prefixed with 0x in hex. 220 Warning: Many of these options can produce a lot of 221 output and make your system unusable. Be very careful. 222 223 224 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT 225 226 acpi_pm_good [IA-32,X86-64] 227 Override the pmtimer bug detection: force the kernel 228 to assume that this machine's pmtimer latches its value 229 and always returns good values. 230 231 enable_timer_pin_1 [i386,x86-64] 232 Enable PIN 1 of APIC timer 233 Can be useful to work around chipset bugs 234 (in particular on some ATI chipsets). 235 The kernel tries to set a reasonable default. 236 237 disable_timer_pin_1 [i386,x86-64] 238 Disable PIN 1 of APIC timer 239 Can be useful to work around chipset bugs. 240 241 ad1816= [HW,OSS] 242 Format: <io>,<irq>,<dma>,<dma2> 243 See also Documentation/sound/oss/AD1816. 244 245 ad1848= [HW,OSS] 246 Format: <io>,<irq>,<dma>,<dma2>,<type> 247 248 adlib= [HW,OSS] 249 Format: <io> 250 251 advansys= [HW,SCSI] 252 See header of drivers/scsi/advansys.c. 253 254 advwdt= [HW,WDT] Advantech WDT 255 Format: <iostart>,<iostop> 256 257 aedsp16= [HW,OSS] Audio Excel DSP 16 258 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq> 259 See also header of sound/oss/aedsp16.c. 260 261 aha152x= [HW,SCSI] 262 See Documentation/scsi/aha152x.txt. 263 264 aha1542= [HW,SCSI] 265 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]] 266 267 aic7xxx= [HW,SCSI] 268 See Documentation/scsi/aic7xxx.txt. 269 270 aic79xx= [HW,SCSI] 271 See Documentation/scsi/aic79xx.txt. 272 273 amijoy.map= [HW,JOY] Amiga joystick support 274 Map of devices attached to JOY0DAT and JOY1DAT 275 Format: <a>,<b> 276 See also Documentation/kernel/input/joystick.txt 277 278 analog.map= [HW,JOY] Analog joystick and gamepad support 279 Specifies type or capabilities of an analog joystick 280 connected to one of 16 gameports 281 Format: <type1>,<type2>,..<type16> 282 283 apc= [HW,SPARC] 284 Power management functions (SPARCstation-4/5 + deriv.) 285 Format: noidle 286 Disable APC CPU standby support. SPARCstation-Fox does 287 not play well with APC CPU idle - disable it if you have 288 APC and your system crashes randomly. 289 290 apic= [APIC,i386] Change the output verbosity whilst booting 291 Format: { quiet (default) | verbose | debug } 292 Change the amount of debugging information output 293 when initialising the APIC and IO-APIC components. 294 295 apm= [APM] Advanced Power Management 296 See header of arch/i386/kernel/apm.c. 297 298 applicom= [HW] 299 Format: <mem>,<irq> 300 301 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards 302 Format: <io>,<irq>,<nodeID> 303 304 ataflop= [HW,M68k] 305 306 atarimouse= [HW,MOUSE] Atari Mouse 307 308 atascsi= [HW,SCSI] Atari SCSI 309 310 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, 311 EzKey and similar keyboards 312 313 atkbd.reset= [HW] Reset keyboard during initialization 314 315 atkbd.set= [HW] Select keyboard code set 316 Format: <int> (2 = AT (default), 3 = PS/2) 317 318 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar 319 keyboards 320 321 atkbd.softraw= [HW] Choose between synthetic and real raw mode 322 Format: <bool> (0 = real, 1 = synthetic (default)) 323 324 atkbd.softrepeat= [HW] 325 Use software keyboard repeat 326 327 autotest [IA64] 328 329 aztcd= [HW,CD] Aztech CD268 CDROM driver 330 Format: <io>,0x79 (?) 331 332 baycom_epp= [HW,AX25] 333 Format: <io>,<mode> 334 335 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem 336 Format: <io>,<mode> 337 See header of drivers/net/hamradio/baycom_par.c. 338 339 baycom_ser_fdx= [HW,AX25] 340 BayCom Serial Port AX.25 Modem (Full Duplex Mode) 341 Format: <io>,<irq>,<mode>[,<baud>] 342 See header of drivers/net/hamradio/baycom_ser_fdx.c. 343 344 baycom_ser_hdx= [HW,AX25] 345 BayCom Serial Port AX.25 Modem (Half Duplex Mode) 346 Format: <io>,<irq>,<mode> 347 See header of drivers/net/hamradio/baycom_ser_hdx.c. 348 349 blkmtd_device= [HW,MTD] 350 blkmtd_erasesz= 351 blkmtd_ro= 352 blkmtd_bs= 353 blkmtd_count= 354 355 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) 356 bttv.radio= Most important insmod options are available as 357 kernel args too. 358 bttv.pll= See Documentation/video4linux/bttv/Insmod-options 359 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST 360 361 BusLogic= [HW,SCSI] 362 See drivers/scsi/BusLogic.c, comment before function 363 BusLogic_ParseDriverOptions(). 364 365 c101= [NET] Moxa C101 synchronous serial card 366 367 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection. 368 Sometimes CPU hardware bugs make them report the cache 369 size incorrectly. The kernel will attempt work arounds 370 to fix known problems, but for some CPUs it is not 371 possible to determine what the correct size should be. 372 This option provides an override for these situations. 373 374 cdu31a= [HW,CD] 375 Format: <io>,<irq>[,PAS] 376 See header of drivers/cdrom/cdu31a.c. 377 378 chandev= [HW,NET] Generic channel device initialisation 379 380 checkreqprot [SELINUX] Set initial checkreqprot flag value. 381 Format: { "0" | "1" } 382 See security/selinux/Kconfig help text. 383 0 -- check protection applied by kernel (includes 384 any implied execute protection). 385 1 -- check protection requested by application. 386 Default value is set via a kernel config option. 387 Value can be changed at runtime via 388 /selinux/checkreqprot. 389 390 clock= [BUGS=IA-32, HW] gettimeofday clocksource override. 391 [Deprecated] 392 Forces specified clocksource (if available) to be used 393 when calculating gettimeofday(). If specified 394 clocksource is not available, it defaults to PIT. 395 Format: { pit | tsc | cyclone | pmtmr } 396 397 clocksource= [GENERIC_TIME] Override the default clocksource 398 Format: <string> 399 Override the default clocksource and use the clocksource 400 with the name specified. 401 Some clocksource names to choose from, depending on 402 the platform: 403 [all] jiffies (this is the base, fallback clocksource) 404 [ACPI] acpi_pm 405 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, 406 pxa_timer,timer3,32k_counter,timer0_1 407 [AVR32] avr32 408 [IA-32] pit,hpet,tsc,vmi-timer; 409 scx200_hrt on Geode; cyclone on IBM x440 410 [MIPS] MIPS 411 [PARISC] cr16 412 [S390] tod 413 [SH] SuperH 414 [SPARC64] tick 415 [X86-64] hpet,tsc 416 417 code_bytes [IA32] How many bytes of object code to print in an 418 oops report. 419 Range: 0 - 8192 420 Default: 64 421 422 disable_8254_timer 423 enable_8254_timer 424 [IA32/X86_64] Disable/Enable interrupt 0 timer routing 425 over the 8254 in addition to over the IO-APIC. The 426 kernel tries to set a sensible default. 427 428 hpet= [IA-32,HPET] option to disable HPET and use PIT. 429 Format: disable 430 431 cm206= [HW,CD] 432 Format: { auto | [<io>,][<irq>] } 433 434 com20020= [HW,NET] ARCnet - COM20020 chipset 435 Format: 436 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] 437 438 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) 439 Format: <io>[,<irq>] 440 441 com90xx= [HW,NET] 442 ARCnet - COM90xx chipset (memory-mapped buffers) 443 Format: <io>[,<irq>[,<memstart>]] 444 445 condev= [HW,S390] console device 446 conmode= 447 448 console= [KNL] Output console device and options. 449 450 tty<n> Use the virtual console device <n>. 451 452 ttyS<n>[,options] 453 ttyUSB0[,options] 454 Use the specified serial port. The options are of 455 the form "bbbbpnf", where "bbbb" is the baud rate, 456 "p" is parity ("n", "o", or "e"), "n" is number of 457 bits, and "f" is flow control ("r" for RTS or 458 omit it). Default is "9600n8". 459 460 See Documentation/serial-console.txt for more 461 information. See 462 Documentation/networking/netconsole.txt for an 463 alternative. 464 465 uart,io,<addr>[,options] 466 uart,mmio,<addr>[,options] 467 Start an early, polled-mode console on the 8250/16550 468 UART at the specified I/O port or MMIO address, 469 switching to the matching ttyS device later. The 470 options are the same as for ttyS, above. 471 472 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver 473 Format: 474 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] 475 476 cpia_pp= [HW,PPT] 477 Format: { parport<nr> | auto | none } 478 479 crashkernel=nn[KMG]@ss[KMG] 480 [KNL] Reserve a chunk of physical memory to 481 hold a kernel to switch to with kexec on panic. 482 483 cs4232= [HW,OSS] 484 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq> 485 486 cs89x0_dma= [HW,NET] 487 Format: <dma> 488 489 cs89x0_media= [HW,NET] 490 Format: { rj45 | aui | bnc } 491 492 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter. 493 494 dasd= [HW,NET] 495 See header of drivers/s390/block/dasd_devmap.c. 496 497 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port 498 (one device per port) 499 Format: <port#>,<type> 500 See also Documentation/input/joystick-parport.txt 501 502 debug [KNL] Enable kernel debugging (events log level). 503 504 debug_locks_verbose= 505 [KNL] verbose self-tests 506 Format=<0|1> 507 Print debugging info while doing the locking API 508 self-tests. 509 We default to 0 (no extra messages), setting it to 510 1 will print _a lot_ more information - normally 511 only useful to kernel developers. 512 513 decnet= [HW,NET] 514 Format: <area>[,<node>] 515 See also Documentation/networking/decnet.txt. 516 517 default_blu= [VT] 518 Format: <blue0>,<blue1>,<blue2>,...,<blue15> 519 Change the default blue palette of the console. 520 This is a 16-member array composed of values 521 ranging from 0-255. 522 523 default_grn= [VT] 524 Format: <green0>,<green1>,<green2>,...,<green15> 525 Change the default green palette of the console. 526 This is a 16-member array composed of values 527 ranging from 0-255. 528 529 default_red= [VT] 530 Format: <red0>,<red1>,<red2>,...,<red15> 531 Change the default red palette of the console. 532 This is a 16-member array composed of values 533 ranging from 0-255. 534 535 default_utf8= [VT] 536 Format=<0|1> 537 Set system-wide default UTF-8 mode for all tty's. 538 Default is 0 and by setting to 1, it enables UTF-8 539 mode for all newly opened or allocated terminals. 540 541 dhash_entries= [KNL] 542 Set number of hash buckets for dentry cache. 543 544 digi= [HW,SERIAL] 545 IO parameters + enable/disable command. 546 547 digiepca= [HW,SERIAL] 548 See drivers/char/README.epca and 549 Documentation/digiepca.txt. 550 551 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA 552 support available. 553 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]] 554 555 dmasound= [HW,OSS] Sound subsystem buffers 556 557 dscc4.setup= [NET] 558 559 dtc3181e= [HW,SCSI] 560 561 earlyprintk= [IA-32,X86-64,SH] 562 earlyprintk=vga 563 earlyprintk=serial[,ttySn[,baudrate]] 564 565 Append ",keep" to not disable it when the real console 566 takes over. 567 568 Only vga or serial at a time, not both. 569 570 Currently only ttyS0 and ttyS1 are supported. 571 572 Interaction with the standard serial driver is not 573 very good. 574 575 The VGA output is eventually overwritten by the real 576 console. 577 578 eata= [HW,SCSI] 579 580 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode 581 Format: <int> 582 0: polling mode 583 non-0: interrupt mode (default) 584 585 eda= [HW,PS2] 586 587 edb= [HW,PS2] 588 589 edd= [EDD] 590 Format: {"of[f]" | "sk[ipmbr]"} 591 See comment in arch/i386/boot/edd.S 592 593 eicon= [HW,ISDN] 594 Format: <id>,<membase>,<irq> 595 596 eisa_irq_edge= [PARISC,HW] 597 See header of drivers/parisc/eisa.c. 598 599 elanfreq= [IA-32] 600 See comment before function elanfreq_setup() in 601 arch/i386/kernel/cpu/cpufreq/elanfreq.c. 602 603 elevator= [IOSCHED] 604 Format: {"anticipatory" | "cfq" | "deadline" | "noop"} 605 See Documentation/block/as-iosched.txt and 606 Documentation/block/deadline-iosched.txt for details. 607 608 elfcorehdr= [IA-32, X86_64] 609 Specifies physical address of start of kernel core 610 image elf header. Generally kexec loader will 611 pass this option to capture kernel. 612 See Documentation/kdump/kdump.txt for details. 613 614 enforcing [SELINUX] Set initial enforcing status. 615 Format: {"0" | "1"} 616 See security/selinux/Kconfig help text. 617 0 -- permissive (log only, no denials). 618 1 -- enforcing (deny and log). 619 Default value is 0. 620 Value can be changed at runtime via /selinux/enforce. 621 622 es1371= [HW,OSS] 623 Format: <spdif>,[<nomix>,[<amplifier>]] 624 See also header of sound/oss/es1371.c. 625 626 ether= [HW,NET] Ethernet cards parameters 627 This option is obsoleted by the "netdev=" option, which 628 has equivalent usage. See its documentation for details. 629 630 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog. 631 Format: <io>[,<irq>] 632 633 failslab= 634 fail_page_alloc= 635 fail_make_request=[KNL] 636 General fault injection mechanism. 637 Format: <interval>,<probability>,<space>,<times> 638 See also /Documentation/fault-injection/. 639 640 fd_mcs= [HW,SCSI] 641 See header of drivers/scsi/fd_mcs.c. 642 643 fdomain= [HW,SCSI] 644 See header of drivers/scsi/fdomain.c. 645 646 floppy= [HW] 647 See Documentation/floppy.txt. 648 649 gamecon.map[2|3]= 650 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad 651 support via parallel port (up to 5 devices per port) 652 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> 653 See also Documentation/input/joystick-parport.txt 654 655 gamma= [HW,DRM] 656 657 gdth= [HW,SCSI] 658 See header of drivers/scsi/gdth.c. 659 660 gpt [EFI] Forces disk with valid GPT signature but 661 invalid Protective MBR to be treated as GPT. 662 663 gscd= [HW,CD] 664 Format: <io> 665 666 gvp11= [HW,SCSI] 667 668 hashdist= [KNL,NUMA] Large hashes allocated during boot 669 are distributed across NUMA nodes. Defaults on 670 for IA-64, off otherwise. 671 Format: 0 | 1 (for off | on) 672 673 hcl= [IA-64] SGI's Hardware Graph compatibility layer 674 675 hd= [EIDE] (E)IDE hard drive subsystem geometry 676 Format: <cyl>,<head>,<sect> 677 678 hd?= [HW] (E)IDE subsystem 679 hd?lun= See Documentation/ide.txt. 680 681 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact 682 size of <nn>. This works even on boxes that have no 683 highmem otherwise. This also works to reduce highmem 684 size on bigger boxes. 685 686 highres= [KNL] Enable/disable high resolution timer mode. 687 Valid parameters: "on", "off" 688 Default: "on" 689 690 hisax= [HW,ISDN] 691 See Documentation/isdn/README.HiSax. 692 693 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages. 694 695 i8042.direct [HW] Put keyboard port into non-translated mode 696 i8042.dumbkbd [HW] Pretend that controller can only read data from 697 keyboard and cannot control its state 698 (Don't attempt to blink the leds) 699 i8042.noaux [HW] Don't check for auxiliary (== mouse) port 700 i8042.nokbd [HW] Don't check/create keyboard port 701 i8042.nomux [HW] Don't check presence of an active multiplexing 702 controller 703 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX 704 controllers 705 i8042.panicblink= 706 [HW] Frequency with which keyboard LEDs should blink 707 when kernel panics (default is 0.5 sec) 708 i8042.reset [HW] Reset the controller during init and cleanup 709 i8042.unlock [HW] Unlock (ignore) the keylock 710 711 i810= [HW,DRM] 712 713 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data 714 indicates that the driver is running on unsupported 715 hardware. 716 i8k.force [HW] Activate i8k driver even if SMM BIOS signature 717 does not match list of supported models. 718 i8k.power_status 719 [HW] Report power status in /proc/i8k 720 (disabled by default) 721 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN 722 capability is set. 723 724 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter 725 See Documentation/mca.txt. 726 727 icn= [HW,ISDN] 728 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] 729 730 ide= [HW] (E)IDE subsystem 731 Format: ide=nodma or ide=doubler or ide=reverse 732 See Documentation/ide.txt. 733 734 ide?= [HW] (E)IDE subsystem 735 Format: ide?=noprobe or chipset specific parameters. 736 See Documentation/ide.txt. 737 738 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed 739 See Documentation/ide.txt. 740 741 idle= [X86] 742 Format: idle=poll or idle=mwait 743 Poll forces a polling idle loop that can slightly improves the performance 744 of waking up a idle CPU, but will use a lot of power and make the system 745 run hot. Not recommended. 746 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose 747 to not use it because it doesn't save as much power as a normal idle 748 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same 749 as idle=poll. 750 751 ignore_loglevel [KNL] 752 Ignore loglevel setting - this will print /all/ 753 kernel messages to the console. Useful for debugging. 754 755 ihash_entries= [KNL] 756 Set number of hash buckets for inode cache. 757 758 in2000= [HW,SCSI] 759 See header of drivers/scsi/in2000.c. 760 761 init= [KNL] 762 Format: <full_path> 763 Run specified binary instead of /sbin/init as init 764 process. 765 766 initcall_debug [KNL] Trace initcalls as they are executed. Useful 767 for working out where the kernel is dying during 768 startup. 769 770 initrd= [BOOT] Specify the location of the initial ramdisk 771 772 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver 773 Format: <irq> 774 775 inttest= [IA64] 776 777 io7= [HW] IO7 for Marvel based alpha systems 778 See comment before marvel_specify_io7 in 779 arch/alpha/kernel/core_marvel.c. 780 781 ip= [IP_PNP] 782 See Documentation/nfsroot.txt. 783 784 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards 785 See comment before ip2_setup() in drivers/char/ip2.c. 786 787 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller 788 See header of drivers/scsi/ips.c. 789 790 ports= [IP_VS_FTP] IPVS ftp helper module 791 Default is 21. 792 Up to 8 (IP_VS_APP_MAX_PORTS) ports 793 may be specified. 794 Format: <port>,<port>.... 795 796 irqfixup [HW] 797 When an interrupt is not handled search all handlers 798 for it. Intended to get systems with badly broken 799 firmware running. 800 801 irqpoll [HW] 802 When an interrupt is not handled search all handlers 803 for it. Also check all handlers each timer 804 interrupt. Intended to get systems with badly broken 805 firmware running. 806 807 isapnp= [ISAPNP] 808 Format: <RDP>,<reset>,<pci_scan>,<verbosity> 809 810 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. 811 Format: 812 <cpu number>,...,<cpu number> 813 or 814 <cpu number>-<cpu number> (must be a positive range in ascending order) 815 or a mixture 816 <cpu number>,...,<cpu number>-<cpu number> 817 This option can be used to specify one or more CPUs 818 to isolate from the general SMP balancing and scheduling 819 algorithms. The only way to move a process onto or off 820 an "isolated" CPU is via the CPU affinity syscalls. 821 <cpu number> begins at 0 and the maximum value is 822 "number of CPUs in system - 1". 823 824 This option is the preferred way to isolate CPUs. The 825 alternative -- manually setting the CPU mask of all 826 tasks in the system -- can cause problems and 827 suboptimal load balancer performance. 828 829 isp16= [HW,CD] 830 Format: <io>,<irq>,<dma>,<setup> 831 832 iucv= [HW,NET] 833 834 js= [HW,JOY] Analog joystick 835 See Documentation/input/joystick.txt. 836 837 keepinitrd [HW,ARM] 838 839 kstack=N [IA-32,X86-64] Print N words from the kernel stack 840 in oops dumps. 841 842 l2cr= [PPC] 843 844 lapic [IA-32,APIC] Enable the local APIC even if BIOS 845 disabled it. 846 847 lapic_timer_c2_ok [IA-32,x86-64,APIC] trust the local apic timer in 848 C2 power state. 849 850 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip 851 Format: addr:<io>,irq:<irq> 852 853 legacy_serial.force [HW,IA-32,X86-64] 854 Probe for COM ports at legacy addresses even 855 if PNPBIOS or ACPI should describe them. This 856 is for working around firmware defects. 857 858 llsc*= [IA64] See function print_params() in 859 arch/ia64/sn/kernel/llsc4.c. 860 861 load_ramdisk= [RAM] List of ramdisks to load from floppy 862 See Documentation/ramdisk.txt. 863 864 lockd.nlm_grace_period=P [NFS] Assign grace period. 865 Format: <integer> 866 867 lockd.nlm_tcpport=N [NFS] Assign TCP port. 868 Format: <integer> 869 870 lockd.nlm_timeout=T [NFS] Assign timeout value. 871 Format: <integer> 872 873 lockd.nlm_udpport=M [NFS] Assign UDP port. 874 Format: <integer> 875 876 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver 877 Format: <irq> 878 879 loglevel= All Kernel Messages with a loglevel smaller than the 880 console loglevel will be printed to the console. It can 881 also be changed with klogd or other programs. The 882 loglevels are defined as follows: 883 884 0 (KERN_EMERG) system is unusable 885 1 (KERN_ALERT) action must be taken immediately 886 2 (KERN_CRIT) critical conditions 887 3 (KERN_ERR) error conditions 888 4 (KERN_WARNING) warning conditions 889 5 (KERN_NOTICE) normal but significant condition 890 6 (KERN_INFO) informational 891 7 (KERN_DEBUG) debug-level messages 892 893 log_buf_len=n Sets the size of the printk ring buffer, in bytes. 894 Format: { n | nk | nM } 895 n must be a power of two. The default size 896 is set in the kernel config file. 897 898 lp=0 [LP] Specify parallel ports to use, e.g, 899 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses 900 lp=reset first parallel port). 'lp=0' disables the 901 lp=auto printer driver. 'lp=reset' (which can be 902 specified in addition to the ports) causes 903 attached printers to be reset. Using 904 lp=port1,port2,... specifies the parallel ports 905 to associate lp devices with, starting with 906 lp0. A port specification may be 'none' to skip 907 that lp device, or a parport name such as 908 'parport0'. Specifying 'lp=auto' instead of a 909 port specification list means that device IDs 910 from each port should be examined, to see if 911 an IEEE 1284-compliant printer is attached; if 912 so, the driver will manage that printer. 913 See also header of drivers/char/lp.c. 914 915 lpj=n [KNL] 916 Sets loops_per_jiffy to given constant, thus avoiding 917 time-consuming boot-time autodetection (up to 250 ms per 918 CPU). 0 enables autodetection (default). To determine 919 the correct value for your kernel, boot with normal 920 autodetection and see what value is printed. Note that 921 on SMP systems the preset will be applied to all CPUs, 922 which is likely to cause problems if your CPUs need 923 significantly divergent settings. An incorrect value 924 will cause delays in the kernel to be wrong, leading to 925 unpredictable I/O errors and other breakage. Although 926 unlikely, in the extreme case this might damage your 927 hardware. 928 929 ltpc= [NET] 930 Format: <io>,<irq>,<dma> 931 932 mac5380= [HW,SCSI] Format: 933 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> 934 935 mac53c9x= [HW,SCSI] Format: 936 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> 937 938 machvec= [IA64] Force the use of a particular machine-vector 939 (machvec) in a generic kernel. 940 Example: machvec=hpzx1_swiotlb 941 942 max_loop= [LOOP] Maximum number of loopback devices that can 943 be mounted 944 Format: <1-256> 945 946 maxcpus= [SMP] Maximum number of processors that an SMP kernel 947 should make use of. 948 Using "nosmp" or "maxcpus=0" will disable SMP 949 entirely (the MPS table probe still happens, though). 950 A command-line option of "maxcpus=<NUM>", where <NUM> 951 is an integer greater than 0, limits the maximum number 952 of CPUs activated in SMP mode to <NUM>. 953 Using "maxcpus=1" on an SMP kernel is the trivial 954 case of an SMP kernel with only one CPU. 955 956 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or 957 equal to this physical address is ignored. 958 959 max_luns= [SCSI] Maximum number of LUNs to probe. 960 Should be between 1 and 2^32-1. 961 962 max_report_luns= 963 [SCSI] Maximum number of LUNs received. 964 Should be between 1 and 16384. 965 966 mca-pentium [BUGS=IA-32] 967 968 mcatest= [IA-64] 969 970 mcd= [HW,CD] 971 Format: <port>,<irq>,<mitsumi_bug_93_wait> 972 973 mcdx= [HW,CD] 974 975 mce [IA-32] Machine Check Exception 976 977 md= [HW] RAID subsystems devices and level 978 See Documentation/md.txt. 979 980 mdacon= [MDA] 981 Format: <first>,<last> 982 Specifies range of consoles to be captured by the MDA. 983 984 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory 985 Amount of memory to be used when the kernel is not able 986 to see the whole system memory or for test. 987 [IA-32] Use together with memmap= to avoid physical 988 address space collisions. Without memmap= PCI devices 989 could be placed at addresses belonging to unused RAM. 990 991 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel 992 memory. 993 994 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact 995 E820 memory map, as specified by the user. 996 Such memmap=exactmap lines can be constructed based on 997 BIOS output or other requirements. See the memmap=nn@ss 998 option description. 999 1000 memmap=nn[KMG]@ss[KMG] 1001 [KNL] Force usage of a specific region of memory 1002 Region of memory to be used, from ss to ss+nn. 1003 1004 memmap=nn[KMG]#ss[KMG] 1005 [KNL,ACPI] Mark specific memory as ACPI data. 1006 Region of memory to be used, from ss to ss+nn. 1007 1008 memmap=nn[KMG]$ss[KMG] 1009 [KNL,ACPI] Mark specific memory as reserved. 1010 Region of memory to be used, from ss to ss+nn. 1011 1012 meye.*= [HW] Set MotionEye Camera parameters 1013 See Documentation/video4linux/meye.txt. 1014 1015 mga= [HW,DRM] 1016 1017 mousedev.tap_time= 1018 [MOUSE] Maximum time between finger touching and 1019 leaving touchpad surface for touch to be considered 1020 a tap and be reported as a left button click (for 1021 touchpads working in absolute mode only). 1022 Format: <msecs> 1023 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices 1024 reporting absolute coordinates, such as tablets 1025 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices 1026 reporting absolute coordinates, such as tablets 1027 1028 mpu401= [HW,OSS] 1029 Format: <io>,<irq> 1030 1031 MTD_Partition= [MTD] 1032 Format: <name>,<region-number>,<size>,<offset> 1033 1034 MTD_Region= [MTD] Format: 1035 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] 1036 1037 mtdparts= [MTD] 1038 See drivers/mtd/cmdline.c. 1039 1040 mtouchusb.raw_coordinates= 1041 [HW] Make the MicroTouch USB driver use raw coordinates 1042 ('y', default) or cooked coordinates ('n') 1043 1044 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card 1045 1046 NCR_D700= [HW,SCSI] 1047 See header of drivers/scsi/NCR_D700.c. 1048 1049 ncr5380= [HW,SCSI] 1050 1051 ncr53c400= [HW,SCSI] 1052 1053 ncr53c400a= [HW,SCSI] 1054 1055 ncr53c406a= [HW,SCSI] 1056 1057 ncr53c8xx= [HW,SCSI] 1058 1059 netdev= [NET] Network devices parameters 1060 Format: <irq>,<io>,<mem_start>,<mem_end>,<name> 1061 Note that mem_start is often overloaded to mean 1062 something different and driver-specific. 1063 This usage is only documented in each driver source 1064 file if at all. 1065 1066 nfsaddrs= [NFS] 1067 See Documentation/nfsroot.txt. 1068 1069 nfsroot= [NFS] nfs root filesystem for disk-less boxes. 1070 See Documentation/nfsroot.txt. 1071 1072 nfs.callback_tcpport= 1073 [NFS] set the TCP port on which the NFSv4 callback 1074 channel should listen. 1075 1076 nfs.idmap_cache_timeout= 1077 [NFS] set the maximum lifetime for idmapper cache 1078 entries. 1079 1080 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels 1081 1082 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths 1083 emulation library even if a 387 maths coprocessor 1084 is present. 1085 1086 noacpi [LIBATA] Disables use of ACPI in libata suspend/resume 1087 when set. 1088 Format: <int> 1089 1090 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien 1091 caches in the slab allocator. Saves per-node memory, 1092 but will impact performance. 1093 1094 noalign [KNL,ARM] 1095 1096 noapic [SMP,APIC] Tells the kernel to not make use of any 1097 IOAPICs that may be present in the system. 1098 1099 noasync [HW,M68K] Disables async and sync negotiation for 1100 all devices. 1101 1102 nobats [PPC] Do not use BATs for mapping kernel lowmem 1103 on "Classic" PPC cores. 1104 1105 nocache [ARM] 1106 1107 nodelayacct [KNL] Disable per-task delay accounting 1108 1109 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. 1110 1111 noexec [IA-64] 1112 1113 noexec [IA-32,X86-64] 1114 noexec=on: enable non-executable mappings (default) 1115 noexec=off: disable nn-executable mappings 1116 1117 nofxsr [BUGS=IA-32] Disables x86 floating point extended 1118 register save and restore. The kernel will only save 1119 legacy floating-point registers on task switch. 1120 1121 nohlt [BUGS=ARM] 1122 1123 no-hlt [BUGS=IA-32] Tells the kernel that the hlt 1124 instruction doesn't work correctly and not to 1125 use it. 1126 1127 nohalt [IA-64] Tells the kernel not to use the power saving 1128 function PAL_HALT_LIGHT when idle. This increases 1129 power-consumption. On the positive side, it reduces 1130 interrupt wake-up latency, which may improve performance 1131 in certain environments such as networked servers or 1132 real-time systems. 1133 1134 nohz= [KNL] Boottime enable/disable dynamic ticks 1135 Valid arguments: on, off 1136 Default: on 1137 1138 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing 1139 1140 noirqdebug [IA-32] Disables the code which attempts to detect and 1141 disable unhandled interrupt sources. 1142 1143 no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for 1144 broken timer IRQ sources. 1145 1146 noisapnp [ISAPNP] Disables ISA PnP code. 1147 1148 noinitrd [RAM] Tells the kernel not to load any configured 1149 initial RAM disk. 1150 1151 nointroute [IA-64] 1152 1153 nolapic [IA-32,APIC] Do not enable or use the local APIC. 1154 1155 nolapic_timer [IA-32,APIC] Do not use the local APIC timer. 1156 1157 noltlbs [PPC] Do not use large page/tlb entries for kernel 1158 lowmem mapping on PPC40x. 1159 1160 nomca [IA-64] Disable machine check abort handling 1161 1162 nomce [IA-32] Machine Check Exception 1163 1164 noreplace-paravirt [IA-32,PV_OPS] Don't patch paravirt_ops 1165 1166 noreplace-smp [IA-32,SMP] Don't replace SMP instructions 1167 with UP alternatives 1168 1169 noresidual [PPC] Don't use residual data on PReP machines. 1170 1171 noresume [SWSUSP] Disables resume and restores original swap 1172 space. 1173 1174 no-scroll [VGA] Disables scrollback. 1175 This is required for the Braillex ib80-piezo Braille 1176 reader made by F.H. Papenmeier (Germany). 1177 1178 nosbagart [IA-64] 1179 1180 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support. 1181 1182 nosmp [SMP] Tells an SMP kernel to act as a UP kernel. 1183 1184 nosync [HW,M68K] Disables sync negotiation for all devices. 1185 1186 notsc [BUGS=IA-32] Disable Time Stamp Counter 1187 1188 nousb [USB] Disable the USB subsystem 1189 1190 nowb [ARM] 1191 1192 nr_uarts= [SERIAL] maximum number of UARTs to be registered. 1193 1194 opl3= [HW,OSS] 1195 Format: <io> 1196 1197 opl3sa2= [HW,OSS] Format: 1198 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple] 1199 1200 oprofile.timer= [HW] 1201 Use timer interrupt instead of performance counters 1202 1203 optcd= [HW,CD] 1204 Format: <io> 1205 1206 osst= [HW,SCSI] SCSI Tape Driver 1207 Format: <buffer_size>,<write_threshold> 1208 See also Documentation/scsi/st.txt. 1209 1210 panic= [KNL] Kernel behaviour on panic 1211 Format: <timeout> 1212 1213 parkbd.port= [HW] Parallel port number the keyboard adapter is 1214 connected to, default is 0. 1215 Format: <parport#> 1216 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, 1217 0 for XT, 1 for AT (default is AT). 1218 Format: <mode> 1219 1220 parport= [HW,PPT] Specify parallel ports. 0 disables. 1221 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } 1222 Use 'auto' to force the driver to use any 1223 IRQ/DMA settings detected (the default is to 1224 ignore detected IRQ/DMA settings because of 1225 possible conflicts). You can specify the base 1226 address, IRQ, and DMA settings; IRQ and DMA 1227 should be numbers, or 'auto' (for using detected 1228 settings on that particular port), or 'nofifo' 1229 (to avoid using a FIFO even if it is detected). 1230 Parallel ports are assigned in the order they 1231 are specified on the command line, starting 1232 with parport0. 1233 1234 parport_init_mode= [HW,PPT] 1235 Configure VIA parallel port to operate in 1236 a specific mode. This is necessary on Pegasos 1237 computer where firmware has no options for setting 1238 up parallel port mode and sets it to spp. 1239 Currently this function knows 686a and 8231 chips. 1240 Format: [spp|ps2|epp|ecp|ecpepp] 1241 1242 pas2= [HW,OSS] Format: 1243 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16> 1244 1245 pas16= [HW,SCSI] 1246 See header of drivers/scsi/pas16.c. 1247 1248 pause_on_oops= 1249 Halt all CPUs after the first oops has been printed for 1250 the specified number of seconds. This is to be used if 1251 your oopses keep scrolling off the screen. 1252 1253 pcbit= [HW,ISDN] 1254 1255 pcd. [PARIDE] 1256 See header of drivers/block/paride/pcd.c. 1257 See also Documentation/paride.txt. 1258 1259 pci=option[,option...] [PCI] various PCI subsystem options: 1260 off [IA-32] don't probe for the PCI bus 1261 bios [IA-32] force use of PCI BIOS, don't access 1262 the hardware directly. Use this if your machine 1263 has a non-standard PCI host bridge. 1264 nobios [IA-32] disallow use of PCI BIOS, only direct 1265 hardware access methods are allowed. Use this 1266 if you experience crashes upon bootup and you 1267 suspect they are caused by the BIOS. 1268 conf1 [IA-32] Force use of PCI Configuration 1269 Mechanism 1. 1270 conf2 [IA-32] Force use of PCI Configuration 1271 Mechanism 2. 1272 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI 1273 Configuration 1274 nomsi [MSI] If the PCI_MSI kernel config parameter is 1275 enabled, this kernel boot option can be used to 1276 disable the use of MSI interrupts system-wide. 1277 nosort [IA-32] Don't sort PCI devices according to 1278 order given by the PCI BIOS. This sorting is 1279 done to get a device order compatible with 1280 older kernels. 1281 biosirq [IA-32] Use PCI BIOS calls to get the interrupt 1282 routing table. These calls are known to be buggy 1283 on several machines and they hang the machine 1284 when used, but on other computers it's the only 1285 way to get the interrupt routing table. Try 1286 this option if the kernel is unable to allocate 1287 IRQs or discover secondary PCI buses on your 1288 motherboard. 1289 rom [IA-32] Assign address space to expansion ROMs. 1290 Use with caution as certain devices share 1291 address decoders between ROMs and other 1292 resources. 1293 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be 1294 assigned automatically to PCI devices. You can 1295 make the kernel exclude IRQs of your ISA cards 1296 this way. 1297 pirqaddr=0xAAAAA [IA-32] Specify the physical address 1298 of the PIRQ table (normally generated 1299 by the BIOS) if it is outside the 1300 F0000h-100000h range. 1301 lastbus=N [IA-32] Scan all buses thru bus #N. Can be 1302 useful if the kernel is unable to find your 1303 secondary buses and you want to tell it 1304 explicitly which ones they are. 1305 assign-busses [IA-32] Always assign all PCI bus 1306 numbers ourselves, overriding 1307 whatever the firmware may have done. 1308 usepirqmask [IA-32] Honor the possible IRQ mask stored 1309 in the BIOS $PIR table. This is needed on 1310 some systems with broken BIOSes, notably 1311 some HP Pavilion N5400 and Omnibook XE3 1312 notebooks. This will have no effect if ACPI 1313 IRQ routing is enabled. 1314 noacpi [IA-32] Do not use ACPI for IRQ routing 1315 or for PCI scanning. 1316 routeirq Do IRQ routing for all PCI devices. 1317 This is normally done in pci_enable_device(), 1318 so this option is a temporary workaround 1319 for broken drivers that don't call it. 1320 firmware [ARM] Do not re-enumerate the bus but instead 1321 just use the configuration from the 1322 bootloader. This is currently used on 1323 IXP2000 systems where the bus has to be 1324 configured a certain way for adjunct CPUs. 1325 noearly [X86] Don't do any early type 1 scanning. 1326 This might help on some broken boards which 1327 machine check when some devices' config space 1328 is read. But various workarounds are disabled 1329 and some IOMMU drivers will not work. 1330 bfsort Sort PCI devices into breadth-first order. 1331 This sorting is done to get a device 1332 order compatible with older (<= 2.4) kernels. 1333 nobfsort Don't sort PCI devices into breadth-first order. 1334 cbiosize=nn[KMG] The fixed amount of bus space which is 1335 reserved for the CardBus bridge's IO window. 1336 The default value is 256 bytes. 1337 cbmemsize=nn[KMG] The fixed amount of bus space which is 1338 reserved for the CardBus bridge's memory 1339 window. The default value is 64 megabytes. 1340 1341 pcmv= [HW,PCMCIA] BadgePAD 4 1342 1343 pd. [PARIDE] 1344 See Documentation/paride.txt. 1345 1346 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at 1347 boot time. 1348 Format: { 0 | 1 } 1349 See arch/parisc/kernel/pdc_chassis.c 1350 1351 pf. [PARIDE] 1352 See Documentation/paride.txt. 1353 1354 pg. [PARIDE] 1355 See Documentation/paride.txt. 1356 1357 pirq= [SMP,APIC] Manual mp-table setup 1358 See Documentation/i386/IO-APIC.txt. 1359 1360 plip= [PPT,NET] Parallel port network link 1361 Format: { parport<nr> | timid | 0 } 1362 See also Documentation/parport.txt. 1363 1364 pnpacpi= [ACPI] 1365 { off } 1366 1367 pnpbios= [ISAPNP] 1368 { on | off | curr | res | no-curr | no-res } 1369 1370 pnp_reserve_irq= 1371 [ISAPNP] Exclude IRQs for the autoconfiguration 1372 1373 pnp_reserve_dma= 1374 [ISAPNP] Exclude DMAs for the autoconfiguration 1375 1376 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration 1377 Ranges are in pairs (I/O port base and size). 1378 1379 pnp_reserve_mem= 1380 [ISAPNP] Exclude memory regions for the 1381 autoconfiguration. 1382 Ranges are in pairs (memory base and size). 1383 1384 profile= [KNL] Enable kernel profiling via /proc/profile 1385 Format: [schedule,]<number> 1386 Param: "schedule" - profile schedule points. 1387 Param: <number> - step/bucket size as a power of 2 for 1388 statistical time based profiling. 1389 Param: "sleep" - profile D-state sleeping (millisecs) 1390 1391 processor.max_cstate= [HW,ACPI] 1392 Limit processor to maximum C-state 1393 max_cstate=9 overrides any DMI blacklist limit. 1394 1395 processor.nocst [HW,ACPI] 1396 Ignore the _CST method to determine C-states, 1397 instead using the legacy FADT method 1398 1399 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk 1400 before loading. 1401 See Documentation/ramdisk.txt. 1402 1403 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to 1404 probe for; one of (bare|imps|exps|lifebook|any). 1405 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports 1406 per second. 1407 psmouse.resetafter= [HW,MOUSE] 1408 Try to reset the device after so many bad packets 1409 (0 = never). 1410 psmouse.resolution= 1411 [HW,MOUSE] Set desired mouse resolution, in dpi. 1412 psmouse.smartscroll= 1413 [HW,MOUSE] Controls Logitech smartscroll autorepeat. 1414 0 = disabled, 1 = enabled (default). 1415 1416 pss= [HW,OSS] Personal Sound System (ECHO ESC614) 1417 Format: 1418 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> 1419 1420 pt. [PARIDE] 1421 See Documentation/paride.txt. 1422 1423 quiet [KNL] Disable most log messages 1424 1425 r128= [HW,DRM] 1426 1427 raid= [HW,RAID] 1428 See Documentation/md.txt. 1429 1430 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated] 1431 See Documentation/ramdisk.txt. 1432 1433 ramdisk_blocksize= [RAM] 1434 See Documentation/ramdisk.txt. 1435 1436 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes 1437 New name for the ramdisk parameter. 1438 See Documentation/ramdisk.txt. 1439 1440 rcu.blimit= [KNL,BOOT] Set maximum number of finished 1441 RCU callbacks to process in one batch. 1442 1443 rcu.qhimark= [KNL,BOOT] Set threshold of queued 1444 RCU callbacks over which batch limiting is disabled. 1445 1446 rcu.qlowmark= [KNL,BOOT] Set threshold of queued 1447 RCU callbacks below which batch limiting is re-enabled. 1448 1449 rdinit= [KNL] 1450 Format: <full_path> 1451 Run specified binary instead of /init from the ramdisk, 1452 used for early userspace startup. See initrd. 1453 1454 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode 1455 Format: <reboot_mode>[,<reboot_mode2>[,...]] 1456 See arch/*/kernel/reboot.c or arch/*/kernel/process.c 1457 1458 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area 1459 1460 reservetop= [IA-32] 1461 Format: nn[KMG] 1462 Reserves a hole at the top of the kernel virtual 1463 address space. 1464 1465 reset_devices [KNL] Force drivers to reset the underlying device 1466 during initialization. 1467 1468 resume= [SWSUSP] 1469 Specify the partition device for software suspend 1470 1471 resume_offset= [SWSUSP] 1472 Specify the offset from the beginning of the partition 1473 given by "resume=" at which the swap header is located, 1474 in <PAGE_SIZE> units (needed only for swap files). 1475 See Documentation/power/swsusp-and-swap-files.txt 1476 1477 retain_initrd [RAM] Keep initrd memory after extraction 1478 1479 rhash_entries= [KNL,NET] 1480 Set number of hash buckets for route cache 1481 1482 riscom8= [HW,SERIAL] 1483 Format: <io_board1>[,<io_board2>[,...<io_boardN>]] 1484 1485 ro [KNL] Mount root device read-only on boot 1486 1487 root= [KNL] Root filesystem 1488 1489 rootdelay= [KNL] Delay (in seconds) to pause before attempting to 1490 mount the root filesystem 1491 1492 rootflags= [KNL] Set root filesystem mount option string 1493 1494 rootfstype= [KNL] Set root filesystem type 1495 1496 rw [KNL] Mount root device read-write on boot 1497 1498 S [KNL] Run init in single mode 1499 1500 sa1100ir [NET] 1501 See drivers/net/irda/sa1100_ir.c. 1502 1503 sb= [HW,OSS] 1504 Format: <io>,<irq>,<dma>,<dma2> 1505 1506 sbni= [NET] Granch SBNI12 leased line adapter 1507 1508 sbpcd= [HW,CD] Soundblaster CD adapter 1509 Format: <io>,<type> 1510 See a comment before function sbpcd_setup() in 1511 drivers/cdrom/sbpcd.c. 1512 1513 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver 1514 Format: <io>[,<timeout>[,<isapnp>]] 1515 1516 scsi_debug_*= [SCSI] 1517 See drivers/scsi/scsi_debug.c. 1518 1519 scsi_default_dev_flags= 1520 [SCSI] SCSI default device flags 1521 Format: <integer> 1522 1523 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model 1524 Format: <vendor>:<model>:<flags> 1525 (flags are integer value) 1526 1527 scsi_logging= [SCSI] 1528 1529 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are 1530 discovered. async scans them in kernel threads, 1531 allowing boot to proceed. none ignores them, expecting 1532 user space to do the scan. 1533 1534 selinux [SELINUX] Disable or enable SELinux at boot time. 1535 Format: { "0" | "1" } 1536 See security/selinux/Kconfig help text. 1537 0 -- disable. 1538 1 -- enable. 1539 Default value is set via kernel config option. 1540 If enabled at boot time, /selinux/disable can be used 1541 later to disable prior to initial policy load. 1542 1543 selinux_compat_net = 1544 [SELINUX] Set initial selinux_compat_net flag value. 1545 Format: { "0" | "1" } 1546 0 -- use new secmark-based packet controls 1547 1 -- use legacy packet controls 1548 Default value is 0 (preferred). 1549 Value can be changed at runtime via 1550 /selinux/compat_net. 1551 1552 serialnumber [BUGS=IA-32] 1553 1554 sg_def_reserved_size= [SCSI] 1555 1556 shapers= [NET] 1557 Maximal number of shapers. 1558 1559 sim710= [SCSI,HW] 1560 See header of drivers/scsi/sim710.c. 1561 1562 simeth= [IA-64] 1563 simscsi= 1564 1565 sjcd= [HW,CD] 1566 Format: <io>,<irq>,<dma> 1567 See header of drivers/cdrom/sjcd.c. 1568 1569 slram= [HW,MTD] 1570 1571 slub_debug [MM, SLUB] 1572 Enabling slub_debug allows one to determine the culprit 1573 if slab objects become corrupted. Enabling slub_debug 1574 creates guard zones around objects and poisons objects 1575 when not in use. Also tracks the last alloc / free. 1576 For more information see Documentation/vm/slub.txt. 1577 1578 slub_max_order= [MM, SLUB] 1579 Determines the maximum allowed order for slabs. Setting 1580 this too high may cause fragmentation. 1581 For more information see Documentation/vm/slub.txt. 1582 1583 slub_min_objects= [MM, SLUB] 1584 The minimum objects per slab. SLUB will increase the 1585 slab order up to slub_max_order to generate a 1586 sufficiently big slab to satisfy the number of objects. 1587 The higher the number of objects the smaller the overhead 1588 of tracking slabs. 1589 For more information see Documentation/vm/slub.txt. 1590 1591 slub_min_order= [MM, SLUB] 1592 Determines the mininum page order for slabs. Must be 1593 lower than slub_max_order 1594 For more information see Documentation/vm/slub.txt. 1595 1596 slub_nomerge [MM, SLUB] 1597 Disable merging of slabs of similar size. May be 1598 necessary if there is some reason to distinguish 1599 allocs to different slabs. 1600 For more information see Documentation/vm/slub.txt. 1601 1602 smart2= [HW] 1603 Format: <io1>[,<io2>[,...,<io8>]] 1604 1605 smp-alt-once [IA-32,SMP] On a hotplug CPU system, only 1606 attempt to substitute SMP alternatives once at boot. 1607 1608 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices 1609 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port 1610 smsc-ircc2.ircc_sir= [HW] SIR base I/O port 1611 smsc-ircc2.ircc_fir= [HW] FIR base I/O port 1612 smsc-ircc2.ircc_irq= [HW] IRQ line 1613 smsc-ircc2.ircc_dma= [HW] DMA channel 1614 smsc-ircc2.ircc_transceiver= [HW] Transceiver type: 1615 0: Toshiba Satellite 1800 (GP data pin select) 1616 1: Fast pin select (default) 1617 2: ATC IRMode 1618 1619 snd-ad1816a= [HW,ALSA] 1620 1621 snd-ad1848= [HW,ALSA] 1622 1623 snd-ali5451= [HW,ALSA] 1624 1625 snd-als100= [HW,ALSA] 1626 1627 snd-als4000= [HW,ALSA] 1628 1629 snd-azt2320= [HW,ALSA] 1630 1631 snd-cmi8330= [HW,ALSA] 1632 1633 snd-cmipci= [HW,ALSA] 1634 1635 snd-cs4231= [HW,ALSA] 1636 1637 snd-cs4232= [HW,ALSA] 1638 1639 snd-cs4236= [HW,ALSA] 1640 1641 snd-cs4281= [HW,ALSA] 1642 1643 snd-cs46xx= [HW,ALSA] 1644 1645 snd-dt019x= [HW,ALSA] 1646 1647 snd-dummy= [HW,ALSA] 1648 1649 snd-emu10k1= [HW,ALSA] 1650 1651 snd-ens1370= [HW,ALSA] 1652 1653 snd-ens1371= [HW,ALSA] 1654 1655 snd-es968= [HW,ALSA] 1656 1657 snd-es1688= [HW,ALSA] 1658 1659 snd-es18xx= [HW,ALSA] 1660 1661 snd-es1938= [HW,ALSA] 1662 1663 snd-es1968= [HW,ALSA] 1664 1665 snd-fm801= [HW,ALSA] 1666 1667 snd-gusclassic= [HW,ALSA] 1668 1669 snd-gusextreme= [HW,ALSA] 1670 1671 snd-gusmax= [HW,ALSA] 1672 1673 snd-hdsp= [HW,ALSA] 1674 1675 snd-ice1712= [HW,ALSA] 1676 1677 snd-intel8x0= [HW,ALSA] 1678 1679 snd-interwave= [HW,ALSA] 1680 1681 snd-interwave-stb= 1682 [HW,ALSA] 1683 1684 snd-korg1212= [HW,ALSA] 1685 1686 snd-maestro3= [HW,ALSA] 1687 1688 snd-mpu401= [HW,ALSA] 1689 1690 snd-mtpav= [HW,ALSA] 1691 1692 snd-nm256= [HW,ALSA] 1693 1694 snd-opl3sa2= [HW,ALSA] 1695 1696 snd-opti92x-ad1848= 1697 [HW,ALSA] 1698 1699 snd-opti92x-cs4231= 1700 [HW,ALSA] 1701 1702 snd-opti93x= [HW,ALSA] 1703 1704 snd-pmac= [HW,ALSA] 1705 1706 snd-rme32= [HW,ALSA] 1707 1708 snd-rme96= [HW,ALSA] 1709 1710 snd-rme9652= [HW,ALSA] 1711 1712 snd-sb8= [HW,ALSA] 1713 1714 snd-sb16= [HW,ALSA] 1715 1716 snd-sbawe= [HW,ALSA] 1717 1718 snd-serial= [HW,ALSA] 1719 1720 snd-sgalaxy= [HW,ALSA] 1721 1722 snd-sonicvibes= [HW,ALSA] 1723 1724 snd-sun-amd7930= 1725 [HW,ALSA] 1726 1727 snd-sun-cs4231= [HW,ALSA] 1728 1729 snd-trident= [HW,ALSA] 1730 1731 snd-usb-audio= [HW,ALSA,USB] 1732 1733 snd-via82xx= [HW,ALSA] 1734 1735 snd-virmidi= [HW,ALSA] 1736 1737 snd-wavefront= [HW,ALSA] 1738 1739 snd-ymfpci= [HW,ALSA] 1740 1741 sonycd535= [HW,CD] 1742 Format: <io>[,<irq>] 1743 1744 sonypi.*= [HW] Sony Programmable I/O Control Device driver 1745 See Documentation/sonypi.txt 1746 1747 specialix= [HW,SERIAL] Specialix multi-serial port adapter 1748 See Documentation/specialix.txt. 1749 1750 spia_io_base= [HW,MTD] 1751 spia_fio_base= 1752 spia_pedr= 1753 spia_peddr= 1754 1755 sscape= [HW,OSS] 1756 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq> 1757 1758 st= [HW,SCSI] SCSI tape parameters (buffers, etc.) 1759 See Documentation/scsi/st.txt. 1760 1761 st0x= [HW,SCSI] 1762 See header of drivers/scsi/seagate.c. 1763 1764 sti= [PARISC,HW] 1765 Format: <num> 1766 Set the STI (builtin display/keyboard on the HP-PARISC 1767 machines) console (graphic card) which should be used 1768 as the initial boot-console. 1769 See also comment in drivers/video/console/sticore.c. 1770 1771 sti_font= [HW] 1772 See comment in drivers/video/console/sticore.c. 1773 1774 stifb= [HW] 1775 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] 1776 1777 sunrpc.pool_mode= 1778 [NFS] 1779 Control how the NFS server code allocates CPUs to 1780 service thread pools. Depending on how many NICs 1781 you have and where their interrupts are bound, this 1782 option will affect which CPUs will do NFS serving. 1783 Note: this parameter cannot be changed while the 1784 NFS server is running. 1785 1786 auto the server chooses an appropriate mode 1787 automatically using heuristics 1788 global a single global pool contains all CPUs 1789 percpu one pool for each CPU 1790 pernode one pool for each NUMA node (equivalent 1791 to global on non-NUMA machines) 1792 1793 swiotlb= [IA-64] Number of I/O TLB slabs 1794 1795 switches= [HW,M68k] 1796 1797 sym53c416= [HW,SCSI] 1798 See header of drivers/scsi/sym53c416.c. 1799 1800 sysrq_always_enabled 1801 [KNL] 1802 Ignore sysrq setting - this boot parameter will 1803 neutralize any effect of /proc/sys/kernel/sysrq. 1804 Useful for debugging. 1805 1806 t128= [HW,SCSI] 1807 See header of drivers/scsi/t128.c. 1808 1809 tdfx= [HW,DRM] 1810 1811 thash_entries= [KNL,NET] 1812 Set number of hash buckets for TCP connection 1813 1814 time Show timing data prefixed to each printk message line 1815 1816 tipar.timeout= [HW,PPT] 1817 Set communications timeout in tenths of a second 1818 (default 15). 1819 1820 tipar.delay= [HW,PPT] 1821 Set inter-bit delay in microseconds (default 10). 1822 1823 tmc8xx= [HW,SCSI] 1824 See header of drivers/scsi/seagate.c. 1825 1826 tmscsim= [HW,SCSI] 1827 See comment before function dc390_setup() in 1828 drivers/scsi/tmscsim.c. 1829 1830 tp720= [HW,PS2] 1831 1832 trix= [HW,OSS] MediaTrix AudioTrix Pro 1833 Format: 1834 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> 1835 1836 tsdev.xres= [TS] Horizontal screen resolution. 1837 tsdev.yres= [TS] Vertical screen resolution. 1838 1839 turbografx.map[2|3]= [HW,JOY] 1840 TurboGraFX parallel port interface 1841 Format: 1842 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> 1843 See also Documentation/input/joystick-parport.txt 1844 1845 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter 1846 See header of drivers/scsi/u14-34f.c. 1847 1848 uart401= [HW,OSS] 1849 Format: <io>,<irq> 1850 1851 uart6850= [HW,OSS] 1852 Format: <io>,<irq> 1853 1854 uhci-hcd.ignore_oc= 1855 [USB] Ignore overcurrent events (default N). 1856 Some badly-designed motherboards generate lots of 1857 bogus events, for ports that aren't wired to 1858 anything. Set this parameter to avoid log spamming. 1859 Note that genuine overcurrent events won't be 1860 reported either. 1861 1862 usbcore.autosuspend= 1863 [USB] The autosuspend time delay (in seconds) used 1864 for newly-detected USB devices (default 2). This 1865 is the time required before an idle device will be 1866 autosuspended. Devices for which the delay is set 1867 to a negative value won't be autosuspended at all. 1868 1869 usbhid.mousepoll= 1870 [USBHID] The interval which mice are to be polled at. 1871 1872 vdso= [IA-32,SH] 1873 vdso=2: enable compat VDSO (default with COMPAT_VDSO) 1874 vdso=1: enable VDSO (default) 1875 vdso=0: disable VDSO mapping 1876 1877 video= [FB] Frame buffer configuration 1878 See Documentation/fb/modedb.txt. 1879 1880 vga= [BOOT,IA-32] Select a particular video mode 1881 See Documentation/i386/boot.txt and 1882 Documentation/svga.txt. 1883 Use vga=ask for menu. 1884 This is actually a boot loader parameter; the value is 1885 passed to the kernel using a special protocol. 1886 1887 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact 1888 size of <nn>. This can be used to increase the 1889 minimum size (128MB on x86). It can also be used to 1890 decrease the size and leave more room for directly 1891 mapped kernel RAM. 1892 1893 vmhalt= [KNL,S390] Perform z/VM CP command after system halt. 1894 Format: <command> 1895 1896 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. 1897 Format: <command> 1898 1899 vmpoff= [KNL,S390] Perform z/VM CP command after power off. 1900 Format: <command> 1901 1902 waveartist= [HW,OSS] 1903 Format: <io>,<irq>,<dma>,<dma2> 1904 1905 wd33c93= [HW,SCSI] 1906 See header of drivers/scsi/wd33c93.c. 1907 1908 wd7000= [HW,SCSI] 1909 See header of drivers/scsi/wd7000.c. 1910 1911 wdt= [WDT] Watchdog 1912 See Documentation/watchdog/watchdog.txt. 1913 1914 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. 1915 xd_geo= See header of drivers/block/xd.c. 1916 1917 xirc2ps_cs= [NET,PCMCIA] 1918 Format: 1919 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] 1920 1921 norandmaps Don't use address space randomization 1922 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space 1923 1924 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging 1925 This is useful to get more information why 1926 you got a "dwarf2 unwinder stuck" 1927 1928______________________________________________________________________ 1929 1930TODO: 1931 1932 Add documentation for ALSA options. 1933 Add more DRM drivers. 1934