SPARC Sparc architecture is enabled.
SWSUSP Software suspend (hibernation) is enabled.
SUSPEND System suspend states are enabled.
+ FTRACE Function tracing enabled.
TS Appropriate touchscreen support is enabled.
+ UMS USB Mass Storage support is enabled.
USB USB support is enabled.
USBHID USB Human Interface Device support is enabled.
V4L Video For Linux support is enabled.
Parameters denoted with BOOT are actually interpreted by the boot
loader, and have no meaning to the kernel directly.
Do not modify the syntax of boot loader parameters without extreme
-need or coordination with <Documentation/x86/i386/boot.txt>.
+need or coordination with <Documentation/x86/boot.txt>.
There are also arch-specific kernel-parameters not documented here.
See for example <Documentation/x86/x86_64/boot-options.txt>.
acpi= [HW,ACPI,X86-64,i386]
Advanced Configuration and Power Interface
- Format: { force | off | ht | strict | noirq }
+ Format: { force | off | ht | strict | noirq | rsdt }
force -- enable ACPI if default was off
off -- disable ACPI if default was on
noirq -- do not use ACPI for IRQ routing
ht -- run only enough ACPI to enable Hyper Threading
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
+ rsdt -- prefer RSDT over (default) XSDT
See also Documentation/power/pm.txt, pci=noacpi
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
- See Documentation/power/video.txt for s3_bios and s3_mode.
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
+ old_ordering, s4_nonvs }
+ See Documentation/power/video.txt for information on
+ s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
s4_nohwsig prevents ACPI hardware signature from being
used during resume from hibernation.
old_ordering causes the ACPI 1.0 ordering of the _PTS
- control method, wrt putting devices into low power
- states, to be enforced (the ACPI 2.0 ordering of _PTS is
- used by default).
+ control method, with respect to putting devices into
+ low power states, to be enforced (the ACPI 2.0 ordering
+ of _PTS is used by default).
+ s4_nonvs prevents the kernel from saving/restoring the
+ ACPI NVS memory during hibernation.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
acpi_skip_timer_override [HW,ACPI]
Recognize and ignore IRQ0/pin2 Interrupt Override.
For broken nForce2 BIOS resulting in XT-PIC timer.
- acpi_use_timer_override [HW,ACPI}
+ acpi_use_timer_override [HW,ACPI]
Use timer override. For some broken Nvidia NF5 boards
that require a timer override, but don't have
HPET
- acpi.debug_layer= [HW,ACPI]
- Format: <int>
- Each bit of the <int> indicates an ACPI debug layer,
- 1: enable, 0: disable. It is useful for boot time
- debugging. After system has booted up, it can be set
- via /sys/module/acpi/parameters/debug_layer.
- CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
- Available bits (add the numbers together) to enable debug output
- for specific parts of the ACPI subsystem:
- 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
- 0x10 namespace 0x20 parser 0x40 dispatcher
- 0x80 executer 0x100 resources 0x200 acpica debugger
- 0x400 os services 0x800 acpica disassembler.
- The number can be in decimal or prefixed with 0x in hex.
- Warning: Many of these options can produce a lot of
- output and make your system unusable. Be very careful.
-
- acpi.debug_level= [HW,ACPI]
+ acpi_backlight= [HW,ACPI]
+ acpi_backlight=vendor
+ acpi_backlight=video
+ If set to vendor, prefer vendor specific driver
+ (e.g. thinkpad_acpi, sony_acpi, etc.) instead
+ of the ACPI video.ko driver.
+
+ acpi_display_output= [HW,ACPI]
+ acpi_display_output=vendor
+ acpi_display_output=video
+ See above.
+
+ acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
+ acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Format: <int>
- Each bit of the <int> indicates an ACPI debug level,
- which corresponds to the level in an ACPI_DEBUG_PRINT
- statement. After system has booted up, this mask
- can be set via /sys/module/acpi/parameters/debug_level.
-
- CONFIG_ACPI_DEBUG must be enabled for this to produce
- any output. The number can be in decimal or prefixed
- with 0x in hex. Some of these options produce so much
- output that the system is unusable.
-
- The following global components are defined by the
- ACPI CA:
- 0x01 error
- 0x02 warn
- 0x04 init
- 0x08 debug object
- 0x10 info
- 0x20 init names
- 0x40 parse
- 0x80 load
- 0x100 dispatch
- 0x200 execute
- 0x400 names
- 0x800 operation region
- 0x1000 bfield
- 0x2000 tables
- 0x4000 values
- 0x8000 objects
- 0x10000 resources
- 0x20000 user requests
- 0x40000 package
- The number can be in decimal or prefixed with 0x in hex.
- Warning: Many of these options can produce a lot of
- output and make your system unusable. Be very careful.
+ CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
+ debug output. Bits in debug_layer correspond to a
+ _COMPONENT in an ACPI source file, e.g.,
+ #define _COMPONENT ACPI_PCI_COMPONENT
+ Bits in debug_level correspond to a level in
+ ACPI_DEBUG_PRINT statements, e.g.,
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
+ The debug_level mask defaults to "info". See
+ Documentation/acpi/debug.txt for more information about
+ debug layers and levels.
+
+ Enable processor driver info messages:
+ acpi.debug_layer=0x20000000
+ Enable PCI/PCI interrupt routing info messages:
+ acpi.debug_layer=0x400000
+ Enable AML "Debug" output, i.e., stores to the Debug
+ object while interpreting AML:
+ acpi.debug_layer=0xffffffff acpi.debug_level=0x2
+ Enable all messages related to ACPI hardware:
+ acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
+
+ Some values produce so much output that the system is
+ unusable. The "log_buf_len" parameter may be useful
+ if you need to capture more output.
acpi.power_nocheck= [HW,ACPI]
Format: 1/0 enable/disable the check of power state.
Possible values are:
isolate - enable device isolation (each device, as far
as possible, will get its own protection
- domain)
+ domain) [default]
+ share - put every device behind one IOMMU into the
+ same protection domain
fullflush - enable flushing of IO/TLB entries when
they are unmapped. Otherwise they are
flushed before they will be reused, which
clearcpuid=BITNUM [X86]
Disable CPUID feature X for the kernel. See
- include/asm-x86/cpufeature.h for the valid bit numbers.
- Note the Linux specific bits are not necessarily
+ arch/x86/include/asm/cpufeature.h for the valid bit
+ numbers. Note the Linux specific bits are not necessarily
stable over kernel options, but the vendor specific
ones should be.
Also note that user programs calling CPUID directly
not work reliably with all consoles, but is known
to work with serial and VGA consoles.
+ coredump_filter=
+ [KNL] Change the default value for
+ /proc/<pid>/coredump_filter.
+ See also Documentation/filesystems/proc.txt.
+
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for a example.
- cs4232= [HW,OSS]
- Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
-
cs89x0_dma= [HW,NET]
Format: <dma>
digiepca= [HW,SERIAL]
See drivers/char/README.epca and
- Documentation/digiepca.txt.
+ Documentation/serial/digiepca.txt.
disable_mtrr_cleanup [X86]
enable_mtrr_cleanup [X86]
Default value is 0.
Value can be changed at runtime via /selinux/enforce.
- es1371= [HW,OSS]
- Format: <spdif>,[<nomix>,[<amplifier>]]
- See also header of sound/oss/es1371.c.
-
ether= [HW,NET] Ethernet cards parameters
This option is obsoleted by the "netdev=" option, which
has equivalent usage. See its documentation for details.
See header of drivers/scsi/fdomain.c.
floppy= [HW]
- See Documentation/floppy.txt.
+ See Documentation/blockdev/floppy.txt.
force_pal_cache_flush
[IA-64] Avoid check_sal_cache_flush which may hang on
parameter will force ia64_sal_cache_flush to call
ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
+ ftrace=[tracer]
+ [ftrace] will set and start the specified tracer
+ as early as possible in order to facilitate early
+ boot debugging.
+
+ ftrace_dump_on_oops
+ [ftrace] will dump the trace buffers on oops.
+
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
hlt [BUGS=ARM,SH]
+ hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
+ terminal devices. Valid values: 0..8
+
i8042.debug [HW] Toggle i8042 debug mode
i8042.direct [HW] Put keyboard port into non-translated mode
i8042.dumbkbd [HW] Pretend that controller can only read data from
icn= [HW,ISDN]
Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
- ide= [HW] (E)IDE subsystem
- Format: ide=nodma or ide=doubler
+ ide-core.nodma= [HW] (E)IDE subsystem
+ Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
+ .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
+ .chs .ignore_cable are additional options
See Documentation/ide/ide.txt.
idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
See Documentation/ide/ide.txt.
idle= [X86]
- Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
- Poll forces a polling idle loop that can slightly improves the performance
- of waking up a idle CPU, but will use a lot of power and make the system
- run hot. Not recommended.
- idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
- to not use it because it doesn't save as much power as a normal idle
- loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
- as idle=poll.
- idle=halt. Halt is forced to be used for CPU idle.
+ Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
+ Poll forces a polling idle loop that can slightly
+ improve the performance of waking up a idle CPU, but
+ will use a lot of power and make the system run hot.
+ Not recommended.
+ idle=mwait: On systems which support MONITOR/MWAIT but
+ the kernel chose to not use it because it doesn't save
+ as much power as a normal idle loop, use the
+ MONITOR/MWAIT idle loop anyways. Performance should be
+ the same as idle=poll.
+ idle=halt: Halt is forced to be used for CPU idle.
In such case C2/C3 won't be used again.
- idle=nomwait. Disable mwait for CPU C-states
+ idle=nomwait: Disable mwait for CPU C-states
ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
Claim all unknown PCI IDE storage controllers.
inttest= [IA64]
+ iomem= Disable strict checking of access to MMIO memory
+ strict regions from userspace.
+ relaxed
+
iommu= [x86]
off
force
intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
+ on
+ Enable intel iommu driver.
off
Disable intel iommu driver.
igfx_off [Default Off]
Format:
<cpu number>,...,<cpu number>
or
- <cpu number>-<cpu number> (must be a positive range in ascending order)
+ <cpu number>-<cpu number>
+ (must be a positive range in ascending order)
or a mixture
<cpu number>,...,<cpu number>-<cpu number>
+
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
- algorithms. The only way to move a process onto or off
- an "isolated" CPU is via the CPU affinity syscalls.
+ algorithms. You can move a process onto or off an
+ "isolated" CPU via the CPU affinity syscalls or cpuset.
<cpu number> begins at 0 and the maximum value is
"number of CPUs in system - 1".
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
- lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
- C2 power state.
+ lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer
+ in C2 power state.
libata.dma= [LIBATA] DMA control
libata.dma=0 Disable all PATA and SATA DMA
If there are multiple matching configurations changing
the same attribute, the last one is used.
+ lmb=debug [KNL] Enable lmb debug messages.
+
load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
it is equivalent to "nosmp", which also disables
the IO APIC.
- max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
- equal to this physical address is ignored.
+ max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
+ or equal to this physical address is ignored.
max_luns= [SCSI] Maximum number of LUNs to probe.
Should be between 1 and 2^32-1.
mga= [HW,DRM]
+ min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
+ physical address is ignored.
+
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
parameter allows control of the logging verbosity for
when a NMI is triggered.
Format: [state][,regs][,debounce][,die]
- nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
+ nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
+ Format: [panic,][num]
+ Valid num: 0,1,2
+ 0 - turn nmi_watchdog off
+ 1 - use the IO-APIC timer for the NMI watchdog
+ 2 - use the local APIC for the NMI watchdog using
+ a performance counter. Note: This will use one performance
+ counter and the local APIC's performance vector.
+ When panic is specified panic when an NMI watchdog timeout occurs.
+ This is useful when you use a panic=... timeout and need the box
+ quickly up again.
+ Instead of 1 and 2 it is possible to use the following
+ symbolic names: lapic and ioapic
+ Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
emulation library even if a 387 maths coprocessor
instruction doesn't work correctly and not to
use it.
+ no_file_caps Tells the kernel not to honor file capabilities. The
+ only way then for a file to be executed with privilege
+ is to be setuid root or executed by root.
+
nohalt [IA-64] Tells the kernel not to use the power saving
function PAL_HALT_LIGHT when idle. This increases
power-consumption. On the positive side, it reduces
nosoftlockup [KNL] Disable the soft-lockup detector.
+ noswapaccount [KNL] Disable accounting of swap in memory resource
+ controller. (See Documentation/controllers/memory.txt)
+
nosync [HW,M68K] Disables sync negotiation for all devices.
notsc [BUGS=X86-32] Disable Time Stamp Counter
nr_uarts= [SERIAL] maximum number of UARTs to be registered.
+ ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
+ See Documentation/debugging-via-ohci1394.txt for more
+ info.
+
olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
Rather than timing out after 20 ms if an EC
command is not properly ACKed, override the length
pcd. [PARIDE]
See header of drivers/block/paride/pcd.c.
- See also Documentation/paride.txt.
+ See also Documentation/blockdev/paride.txt.
pci=option[,option...] [PCI] various PCI subsystem options:
off [X86] don't probe for the PCI bus
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
+ noioapicquirk [APIC] Disable all boot interrupt quirks.
+ Safety option to keep boot IRQs enabled. This
+ should never be necessary.
+ ioapicreroute [APIC] Enable rerouting of boot IRQs to the
+ primary IO-APIC for bridges that cannot disable
+ boot IRQs. This fixes a source of spurious IRQs
+ when the system masks IRQs.
+ noioapicreroute [APIC] Disable workaround that uses the
+ boot IRQ equivalent of an IRQ that connects to
+ a chipset where boot IRQs cannot be disabled.
+ The opposite of ioapicreroute.
biosirq [X86-32] Use PCI BIOS calls to get the interrupt
routing table. These calls are known to be buggy
on several machines and they hang the machine
pcmv= [HW,PCMCIA] BadgePAD 4
pd. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
boot time.
See arch/parisc/kernel/pdc_chassis.c
pf. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pg. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pirq= [SMP,APIC] Manual mp-table setup
See Documentation/x86/i386/IO-APIC.txt.
autoconfiguration.
Ranges are in pairs (memory base and size).
- dynamic_printk
- Enables pr_debug()/dev_dbg() calls if
- CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
- be switched on/off via <debugfs>/dynamic_printk/modules
+ dynamic_printk Enables pr_debug()/dev_dbg() calls if
+ CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
+ These can also be switched on/off via
+ <debugfs>/dynamic_printk/modules
print-fatal-signals=
[KNL] debug: print fatal signals
prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
before loading.
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
probe for; one of (bare|imps|exps|lifebook|any).
<io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
pt. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pty.legacy_count=
[KNL] Number of legacy pty's. Overwrites compiled-in
See Documentation/md.txt.
ramdisk_blocksize= [RAM]
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
rcupdate.blimit= [KNL,BOOT]
Set maximum number of finished RCU callbacks to process
reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Format: <reboot_mode>[,<reboot_mode2>[,...]]
- See arch/*/kernel/reboot.c or arch/*/kernel/process.c
+ See arch/*/kernel/reboot.c or arch/*/kernel/process.c
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
See Documentation/sonypi.txt
specialix= [HW,SERIAL] Specialix multi-serial port adapter
- See Documentation/specialix.txt.
+ See Documentation/serial/specialix.txt.
spia_io_base= [HW,MTD]
spia_fio_base=
st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
See Documentation/scsi/st.txt.
+ stacktrace [FTRACE]
+ Enabled the stack tracer on boot up.
+
sti= [PARISC,HW]
Format: <num>
Set the STI (builtin display/keyboard on the HP-PARISC
thermal.psv= [HW,ACPI]
-1: disable all passive trip points
- <degrees C>: override all passive trip points to this value
+ <degrees C>: override all passive trip points to this
+ value
thermal.tzp= [HW,ACPI]
Specify global default ACPI thermal zone polling rate
See comment before function dc390_setup() in
drivers/scsi/tmscsim.c.
+ topology= [S390]
+ Format: {off | on}
+ Specify if the kernel should make use of the cpu
+ topology informations if the hardware supports these.
+ The scheduler will make use of these informations and
+ e.g. base its process migration decisions on it.
+ Default is off.
+
tp720= [HW,PS2]
trix= [HW,OSS] MediaTrix AudioTrix Pro
Format:
<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
+ tsc= Disable clocksource-must-verify flag for TSC.
+ Format: <string>
+ [x86] reliable: mark tsc clocksource as reliable, this
+ disables clocksource verification at runtime.
+ Used to enable high-resolution timer mode on older
+ hardware, and in virtualized environment.
+
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
Format:
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
+ usb-storage.delay_use=
+ [UMS] The delay in seconds before a new device is
+ scanned for Logical Units (default 5).
+
+ usb-storage.quirks=
+ [UMS] A list of quirks entries to supplement or
+ override the built-in unusual_devs list. List
+ entries are separated by commas. Each entry has
+ the form VID:PID:Flags where VID and PID are Vendor
+ and Product ID values (4-digit hex numbers) and
+ Flags is a set of characters, each corresponding
+ to a common usb-storage quirk flag as follows:
+ a = SANE_SENSE (collect more than 18 bytes
+ of sense data);
+ c = FIX_CAPACITY (decrease the reported
+ device capacity by one sector);
+ h = CAPACITY_HEURISTICS (decrease the
+ reported device capacity by one
+ sector if the number is odd);
+ i = IGNORE_DEVICE (don't bind to this
+ device);
+ l = NOT_LOCKABLE (don't try to lock and
+ unlock ejectable media);
+ m = MAX_SECTORS_64 (don't transfer more
+ than 64 sectors = 32 KB at a time);
+ o = CAPACITY_OK (accept the capacity
+ reported by the device);
+ r = IGNORE_RESIDUE (the device reports
+ bogus residue values);
+ s = SINGLE_LUN (the device has only one
+ Logical Unit);
+ w = NO_WP_DETECT (don't test whether the
+ medium is write-protected).
+ Example: quirks=0419:aaf5:rl,0421:0433:rc
+
add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
kernel's map of available physical RAM.
See Documentation/fb/modedb.txt.
vga= [BOOT,X86-32] Select a particular video mode
- See Documentation/x86/i386/boot.txt and
+ See Documentation/x86/boot.txt and
Documentation/svga.txt.
Use vga=ask for menu.
This is actually a boot loader parameter; the value is
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
- norandmaps Don't use address space randomization
- Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
+ norandmaps Don't use address space randomization. Equivalent to
+ echo 0 > /proc/sys/kernel/randomize_va_space
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