For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force"
are available
- See also Documentation/power/runtime_pm.txt, pci=noacpi
+ See also Documentation/power/runtime_pm.rst, pci=noacpi
acpi_apic_instance= [ACPI, IOAPIC]
Format: <int>
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
+ Documentation/firmware-guide/acpi/debug.rst for more information about
debug layers and levels.
Enable processor driver info messages:
acpi_sleep= [HW,ACPI] Sleep options
Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
old_ordering, nonvs, sci_force_enable, nobl }
- See Documentation/power/video.txt for information on
+ See Documentation/power/video.rst 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.
blkdevparts= Manual partition parsing of block device(s) for
embedded devices based on command line input.
- See Documentation/block/cmdline-partition.txt
+ See Documentation/block/cmdline-partition.rst
boot_delay= Milliseconds to delay each printk during boot.
Values larger than 10 seconds (10000) are changed to
[KNL, x86_64] select a region under 4G first, and
fall back to reserve region above 4G when '@offset'
hasn't been specified.
- See Documentation/kdump/kdump.txt for further details.
+ See Documentation/admin-guide/kdump/kdump.rst for further details.
crashkernel=range1:size1[,range2:size2,...][@offset]
[KNL] Same as above, but depends on the memory
in the running system. The syntax of range is
start-[end] where start and end are both
a memory unit (amount[KMG]). See also
- Documentation/kdump/kdump.txt for an example.
+ Documentation/admin-guide/kdump/kdump.rst for an example.
crashkernel=size[KMG],high
[KNL, x86_64] range could be above 4G. Allow kernel
tracking down these problems.
debug_pagealloc=
- [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
- parameter enables the feature at boot time. In
- default, it is disabled. We can avoid allocating huge
- chunk of memory for debug pagealloc if we don't enable
- it at boot time and the system will work mostly same
- with the kernel built without CONFIG_DEBUG_PAGEALLOC.
+ [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this parameter
+ enables the feature at boot time. By default, it is
+ disabled and the system will work mostly the same as a
+ kernel built without CONFIG_DEBUG_PAGEALLOC.
on: enable the feature
debugpat [X86] Enable PAT debugging
edid/1680x1050.bin, or edid/1920x1080.bin is given
and no file with the same name exists. Details and
instructions how to build your own EDID data are
- available in Documentation/EDID/HOWTO.txt. An EDID
+ available in Documentation/driver-api/edid.rst. An EDID
data set will only be used for a particular connector,
if its name and a colon are prepended to the EDID
name. Each connector may use a unique EDID data
for details.
nompx [X86] Disables Intel Memory Protection Extensions.
- See Documentation/x86/intel_mpx.txt for more
+ See Documentation/x86/intel_mpx.rst for more
information about the feature.
nopku [X86] Disable Memory Protection Keys CPU feature found
that is to be dynamically loaded by Linux. If there are
multiple variables with the same name but with different
vendor GUIDs, all of them will be loaded. See
- Documentation/acpi/ssdt-overlays.txt for details.
+ Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
eisa_irq_edge= [PARISC,HW]
elevator= [IOSCHED]
Format: { "mq-deadline" | "kyber" | "bfq" }
- See Documentation/block/deadline-iosched.txt,
- Documentation/block/kyber-iosched.txt and
- Documentation/block/bfq-iosched.txt for details.
+ See Documentation/block/deadline-iosched.rst,
+ Documentation/block/kyber-iosched.rst and
+ Documentation/block/bfq-iosched.rst for details.
elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
Specifies physical address of start of kernel core
image elf header and optionally the size. Generally
kexec loader will pass this option to capture kernel.
- See Documentation/kdump/kdump.txt for details.
+ See Documentation/admin-guide/kdump/kdump.rst for details.
enable_mtrr_cleanup [X86]
The kernel tries to adjust MTRR layout from continuous
See also Documentation/fault-injection/.
floppy= [HW]
- See Documentation/blockdev/floppy.txt.
+ See Documentation/admin-guide/blockdev/floppy.rst.
force_pal_cache_flush
[IA-64] Avoid check_sal_cache_flush which may hang on
Valid parameters: "on", "off"
Default: "on"
- hisax= [HW,ISDN]
- See Documentation/isdn/README.HiSax.
-
hlt [BUGS=ARM,SH]
hpet= [X86-32,HPET] option to control HPET usage
Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
.vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
.cdrom .chs .ignore_cable are additional options
- See Documentation/ide/ide.txt.
+ See Documentation/ide/ide.rst.
ide-generic.probe-mask= [HW] (E)IDE subsystem
Format: <int>
initrd= [BOOT] Specify the location of the initial ramdisk
+ init_on_alloc= [MM] Fill newly allocated pages and heap objects with
+ zeroes.
+ Format: 0 | 1
+ Default set by CONFIG_INIT_ON_ALLOC_DEFAULT_ON.
+
+ init_on_free= [MM] Fill freed pages and heap objects with zeroes.
+ Format: 0 | 1
+ Default set by CONFIG_INIT_ON_FREE_DEFAULT_ON.
+
init_pkru= [x86] Specify the default memory protection keys rights
register contents for all processes. 0x55555554 by
default (disallow access to all but pkey 0). Can
Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
the default is off.
+ kprobe_event=[probe-list]
+ [FTRACE] Add kprobe events and enable at boot time.
+ The probe-list is a semicolon delimited list of probe
+ definitions. Each definition is same as kprobe_events
+ interface, but the parameters are comma delimited.
+ For example, to add a kprobe event on vfs_read with
+ arg1 and arg2, add to the command line;
+
+ kprobe_event=p,vfs_read,$arg1,$arg2
+
+ See also Documentation/trace/kprobetrace.rst "Kernel
+ Boot Parameter" section.
+
kpti= [ARM64] Control page table isolation of user
and kernel address spaces.
Default: enabled on cores which need mitigation.
memblock=debug [KNL] Enable memblock debug messages.
load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/blockdev/ramdisk.txt.
+ See Documentation/admin-guide/blockdev/ramdisk.rst.
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
mce [X86-32] Machine Check Exception
- mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
+ mce=option [X86-64] See Documentation/x86/x86_64/boot-options.rst
md= [HW] RAID subsystems devices and level
See Documentation/admin-guide/md.rst.
set according to the
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config
option.
- See Documentation/memory-hotplug.txt.
+ See Documentation/admin-guide/mm/memory-hotplug.rst.
memmap=exactmap [KNL,X86] Enable setting of an exact
E820 memory map, as specified by the user.
mem_encrypt=on: Activate SME
mem_encrypt=off: Do not activate SME
- Refer to Documentation/x86/amd-memory-encryption.txt
+ Refer to Documentation/virt/kvm/amd-memory-encryption.rst
for details on when memory encryption can be activated.
mem_sleep_default= [SUSPEND] Default system suspend mode:
0 - turn hardlockup detector in nmi_watchdog off
1 - turn hardlockup detector in nmi_watchdog on
When panic is specified, panic when an NMI watchdog
- timeout occurs (or 'nopanic' to override the opposite
- default). To disable both hard and soft lockup detectors,
+ timeout occurs (or 'nopanic' to not panic on an NMI
+ watchdog, if CONFIG_BOOTPARAM_HARDLOCKUP_PANIC is set)
+ To disable both hard and soft lockup detectors,
please see 'nowatchdog'.
This is useful when you use a panic=... timeout and
need the box quickly up again.
/sys/module/printk/parameters/console_suspend) to
turn on/off it dynamically.
+ novmcoredd [KNL,KDUMP]
+ Disable device dump. Device dump allows drivers to
+ append dump data to vmcore so you can collect driver
+ specified debug info. Drivers can append the data
+ without any limit and this data is stored in memory,
+ so this may cause significant memory stress. Disabling
+ device dump can help save memory but the driver debug
+ data will be no longer available. This parameter
+ is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP
+ is set.
+
noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
caches in the slab allocator. Saves per-node memory,
but will impact performance.
register save and restore. The kernel will only save
legacy floating-point registers on task switch.
- nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
+ nohugeiomap [KNL,x86,PPC] Disable kernel huge I/O mappings.
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
'node', 'default' can be specified
This can be set from sysctl after boot.
- See Documentation/sysctl/vm.txt for details.
+ See Documentation/admin-guide/sysctl/vm.rst for details.
ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
See Documentation/debugging-via-ohci1394.txt for more
pcd. [PARIDE]
See header of drivers/block/paride/pcd.c.
- See also Documentation/blockdev/paride.txt.
+ See also Documentation/admin-guide/blockdev/paride.rst.
pci=option[,option...] [PCI] various PCI subsystem options.
needed on a platform with proper driver support.
pd. [PARIDE]
- See Documentation/blockdev/paride.txt.
+ See Documentation/admin-guide/blockdev/paride.rst.
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
boot time.
and performance comparison.
pf. [PARIDE]
- See Documentation/blockdev/paride.txt.
+ See Documentation/admin-guide/blockdev/paride.rst.
pg. [PARIDE]
- See Documentation/blockdev/paride.txt.
+ See Documentation/admin-guide/blockdev/paride.rst.
pirq= [SMP,APIC] Manual mp-table setup
- See Documentation/x86/i386/IO-APIC.txt.
+ See Documentation/x86/i386/IO-APIC.rst.
plip= [PPT,NET] Parallel port network link
Format: { parport<nr> | timid | 0 }
prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
before loading.
- See Documentation/blockdev/ramdisk.txt.
+ See Documentation/admin-guide/blockdev/ramdisk.rst.
psi= [KNL] Enable or disable pressure stall information
tracking.
pstore.backend= Specify the name of the pstore backend to use
pt. [PARIDE]
- See Documentation/blockdev/paride.txt.
+ See Documentation/admin-guide/blockdev/paride.rst.
pti= [X86_64] Control Page Table Isolation of user and
kernel address spaces. Disabling this feature
See Documentation/admin-guide/md.rst.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
- See Documentation/blockdev/ramdisk.txt.
+ See Documentation/admin-guide/blockdev/ramdisk.rst.
random.trust_cpu={on,off}
[KNL] Enable or disable trusting the use of the
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
- See Documentation/cgroup-v1/cpusets.txt.
+ See Documentation/admin-guide/cgroup-v1/cpusets.rst.
reserve= [KNL,BUGS] Force kernel to ignore I/O ports or memory
Format: <base1>,<size1>[,<base2>,<size2>,...]
Specify the offset from the beginning of the partition
given by "resume=" at which the swap header is located,
in <PAGE_SIZE> units (needed only for swap files).
- See Documentation/power/swsusp-and-swap-files.txt
+ See Documentation/power/swsusp-and-swap-files.rst
resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
read the resume files
Format: <integer>
sonypi.*= [HW] Sony Programmable I/O Control Device driver
- See Documentation/laptops/sonypi.txt
+ See Documentation/admin-guide/laptops/sonypi.rst
spectre_v2= [X86] Control mitigation of Spectre variant 2
(indirect branch speculation) vulnerability.
swapaccount=[0|1]
[KNL] Enable accounting of swap in memory resource
controller if no parameter or 1 is given or disable
- it if 0 is given (See Documentation/cgroup-v1/memory.txt)
+ it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst)
swiotlb= [ARM,IA-64,PPC,MIPS,X86]
Format: { <int> | force | noforce }
Force threading of all interrupt handlers except those
marked explicitly IRQF_NO_THREAD.
- tmem [KNL,XEN]
- Enable the Transcendent memory driver if built-in.
-
- tmem.cleancache=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the cleancache
- API to send anonymous pages to the hypervisor.
-
- tmem.frontswap=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the frontswap
- API to send swap pages to the hypervisor. If disabled
- the selfballooning and selfshrinking are force disabled.
-
- tmem.selfballooning=0|1 [KNL, XEN]
- Default is on (1). Disable the driving of swap pages
- to the hypervisor.
-
- tmem.selfshrinking=0|1 [KNL, XEN]
- Default is on (1). Partial swapoff that immediately
- transfers pages from Xen hypervisor back to the
- kernel based on different criteria.
-
topology= [S390]
Format: {off | on}
Specify if the kernel should make use of the cpu
vector=percpu: enable percpu vector domain
video= [FB] Frame buffer configuration
- See Documentation/fb/modedb.txt.
+ See Documentation/fb/modedb.rst.
video.brightness_switch_enabled= [0,1]
If set to 1, on receiving an ACPI notify event
Can be used multiple times for multiple devices.
vga= [BOOT,X86-32] Select a particular video mode
- See Documentation/x86/boot.txt and
- Documentation/svga.txt.
+ See Documentation/x86/boot.rst and
+ Documentation/admin-guide/svga.rst.
Use vga=ask for menu.
This is actually a boot loader parameter; the value is
passed to the kernel using a special protocol.
Default: 3 = cyan.
watchdog timers [HW,WDT] For information on watchdog timers,
- see Documentation/watchdog/watchdog-parameters.txt
+ see Documentation/watchdog/watchdog-parameters.rst
or other driver-specific files in the
Documentation/watchdog/ directory.
xen_nopv [X86]
Disables the PV optimizations forcing the HVM guest to
run as generic HVM guest with no PV drivers.
+ This option is obsoleted by the "nopv" option, which
+ has equivalent effect for XEN platform.
xen_scrub_pages= [XEN]
Boolean option to control scrubbing pages before giving them back
improve timer resolution at the expense of processing
more timer interrupts.
+ nopv= [X86,XEN,KVM,HYPER_V,VMWARE]
+ Disables the PV optimizations forcing the guest to run
+ as generic guest with no PV drivers. Currently support
+ XEN HVM, KVM, HYPER_V and VMWARE guest.
+
xirc2ps_cs= [NET,PCMCIA]
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
+ xive= [PPC]
+ By default on POWER9 and above, the kernel will
+ natively use the XIVE interrupt controller. This option
+ allows the fallback firmware mode to be used:
+
+ off Fallback to firmware control of XIVE interrupt
+ controller on both pseries and powernv
+ platforms. Only useful on POWER9 and above.
+
xhci-hcd.quirks [USB,KNL]
A hex value specifying bitmask with supplemental xhci
host controller quirks. Meaning of each bit can be
git.samba.org / sfrench / cifs-2.6.git / blobdiff