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-rw-r--r--Documentation/kernel-parameters.txt177
1 files changed, 98 insertions, 79 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 343e0f0f84b..d5418d52891 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -100,7 +100,7 @@ parameter is applicable:
X86-32 X86-32, aka i386 architecture is enabled.
X86-64 X86-64 architecture is enabled.
More X86-64 boot options can be found in
- Documentation/x86_64/boot-options.txt .
+ Documentation/x86/x86_64/boot-options.txt .
X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
In addition, the following text indicates that the option:
@@ -112,10 +112,10 @@ In addition, the following text indicates that the option:
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/i386/boot.txt>.
+need or coordination with <Documentation/x86/i386/boot.txt>.
There are also arch-specific kernel-parameters not documented here.
-See for example <Documentation/x86_64/boot-options.txt>.
+See for example <Documentation/x86/x86_64/boot-options.txt>.
Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
@@ -198,59 +198,42 @@ and is between 256 and 4096 characters. It is defined in the file
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, ...
+ See Documentation/acpi/debug.txt for more information
+ about debug layers and levels.
+
+ Enable AML "Debug" output, i.e., stores to the Debug
+ object while interpreting AML:
+ acpi.debug_layer=0xffffffff acpi.debug_level=0x2
+ Enable PCI/PCI interrupt routing info messages:
+ acpi.debug_layer=0x400000 acpi.debug_level=0x4
+ 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.
@@ -311,7 +294,9 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -646,7 +631,7 @@ and is between 256 and 4096 characters. It is defined in the file
digiepca= [HW,SERIAL]
See drivers/char/README.epca and
- Documentation/digiepca.txt.
+ Documentation/serial/digiepca.txt.
disable_mtrr_cleanup [X86]
enable_mtrr_cleanup [X86]
@@ -757,7 +742,7 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -995,13 +980,15 @@ and is between 256 and 4096 characters. It is defined in the file
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".
@@ -1116,7 +1103,7 @@ and is between 256 and 4096 characters. It is defined in the file
the same attribute, the last one is used.
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>
@@ -1208,8 +1195,8 @@ and is between 256 and 4096 characters. It is defined in the file
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.
@@ -1222,7 +1209,7 @@ and is between 256 and 4096 characters. It is defined in the file
mce [X86-32] Machine Check Exception
- mce=option [X86-64] See Documentation/x86_64/boot-options.txt
+ mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
md= [HW] RAID subsystems devices and level
See Documentation/md.txt.
@@ -1309,6 +1296,9 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -1403,7 +1393,20 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -1470,8 +1473,6 @@ and is between 256 and 4096 characters. It is defined in the file
Valid arguments: on, off
Default: on
- noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
-
noirqdebug [X86-32] Disables the code which attempts to detect and
disable unhandled interrupt sources.
@@ -1613,7 +1614,7 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -1638,6 +1639,17 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -1714,7 +1726,7 @@ and is between 256 and 4096 characters. It is defined in the file
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.
@@ -1722,13 +1734,13 @@ and is between 256 and 4096 characters. It is defined in the file
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/i386/IO-APIC.txt.
+ See Documentation/x86/i386/IO-APIC.txt.
plip= [PPT,NET] Parallel port network link
Format: { parport<nr> | timid | 0 }
@@ -1795,7 +1807,7 @@ and is between 256 and 4096 characters. It is defined in the file
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).
@@ -1815,7 +1827,7 @@ and is between 256 and 4096 characters. It is defined in the file
<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
@@ -1829,10 +1841,10 @@ and is between 256 and 4096 characters. It is defined in the file
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
@@ -2164,7 +2176,7 @@ and is between 256 and 4096 characters. It is defined in the file
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=
@@ -2267,6 +2279,13 @@ and is between 256 and 4096 characters. It is defined in the file
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:
@@ -2343,7 +2362,7 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/fb/modedb.txt.
vga= [BOOT,X86-32] Select a particular video mode
- See Documentation/i386/boot.txt and
+ See Documentation/x86/i386/boot.txt and
Documentation/svga.txt.
Use vga=ask for menu.
This is actually a boot loader parameter; the value is
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-28 00:57:57 +0000