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Docs: admin/kernel-parameters: edit a few boot options
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Clean up some of admin-guide/kernel-parameters.txt:

a. "smt" should be "smt=" (S390)
b. (dropped)
c. Sparc supports the vdso= boot option
d. make the tp_printk options (2) formatting similar to other options
   by adding spacing
e. add "trace_clock=" with a reference to Documentation/trace/ftrace.rst
f. use [IA-64] as documented instead of [ia64]
g. fix formatting and text for test_suspend=
h. fix formatting for swapaccount=
i. fix formatting and grammar for video.brightness_switch_enabled=

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-ia64@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Randy Dunlap authored and Jonathan Corbet committed Apr 16, 2022
1 parent 8285002 commit 59bdbbd
Showing 1 changed file with 36 additions and 11 deletions.
47 changes: 36 additions & 11 deletions Documentation/admin-guide/kernel-parameters.txt
Original file line number Diff line number Diff line change
Expand Up @@ -2814,7 +2814,7 @@
different yeeloong laptops.
Example: machtype=lemote-yeeloong-2f-7inch

max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater
than or equal to this physical address is ignored.

maxcpus= [SMP] Maximum number of processors that an SMP kernel
Expand Down Expand Up @@ -3057,7 +3057,7 @@

mga= [HW,DRM]

min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
physical address is ignored.

mini2440= [ARM,HW,KNL]
Expand Down Expand Up @@ -5388,7 +5388,7 @@
1: Fast pin select (default)
2: ATC IRMode

smt [KNL,S390] Set the maximum number of threads (logical
smt= [KNL,S390] Set the maximum number of threads (logical
CPUs) to use per physical CPU on systems capable of
symmetric multithreading (SMT). Will be capped to the
actual hardware limit.
Expand Down Expand Up @@ -5743,8 +5743,9 @@
This parameter controls use of the Protected
Execution Facility on pSeries.

swapaccount=[0|1]
[KNL] Enable accounting of swap in memory resource
swapaccount= [KNL]
Format: [0|1]
Enable accounting of swap in memory resource
controller if no parameter or 1 is given or disable
it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst)

Expand Down Expand Up @@ -5790,7 +5791,8 @@

tdfx= [HW,DRM]

test_suspend= [SUSPEND][,N]
test_suspend= [SUSPEND]
Format: { "mem" | "standby" | "freeze" }[,N]
Specify "mem" (for Suspend-to-RAM) or "standby" (for
standby suspend) or "freeze" (for suspend type freeze)
as the system sleep state during system startup with
Expand Down Expand Up @@ -5877,6 +5879,28 @@
trace_buf_size=nn[KMG]
[FTRACE] will set tracing buffer size on each cpu.

trace_clock= [FTRACE] Set the clock used for tracing events
at boot up.
local - Use the per CPU time stamp counter
(converted into nanoseconds). Fast, but
depending on the architecture, may not be
in sync between CPUs.
global - Event time stamps are synchronize across
CPUs. May be slower than the local clock,
but better for some race conditions.
counter - Simple counting of events (1, 2, ..)
note, some counts may be skipped due to the
infrastructure grabbing the clock more than
once per event.
uptime - Use jiffies as the time stamp.
perf - Use the same clock that perf uses.
mono - Use ktime_get_mono_fast_ns() for time stamps.
mono_raw - Use ktime_get_raw_fast_ns() for time
stamps.
boot - Use ktime_get_boot_fast_ns() for time stamps.
Architectures may add more clocks. See
Documentation/trace/ftrace.rst for more details.

trace_event=[event-list]
[FTRACE] Set and start specified trace events in order
to facilitate early boot debugging. The event-list is a
Expand All @@ -5899,7 +5923,7 @@
See also Documentation/trace/ftrace.rst "trace options"
section.

tp_printk[FTRACE]
tp_printk [FTRACE]
Have the tracepoints sent to printk as well as the
tracing ring buffer. This is useful for early boot up
where the system hangs or reboots and does not give the
Expand All @@ -5921,7 +5945,7 @@
frequency tracepoints such as irq or sched, can cause
the system to live lock.

tp_printk_stop_on_boot[FTRACE]
tp_printk_stop_on_boot [FTRACE]
When tp_printk (above) is set, it can cause a lot of noise
on the console. It may be useful to only include the
printing of events during boot up, as user space may
Expand Down Expand Up @@ -6270,7 +6294,7 @@
HIGHMEM regardless of setting
of CONFIG_HIGHPTE.

vdso= [X86,SH]
vdso= [X86,SH,SPARC]
On X86_32, this is an alias for vdso32=. Otherwise:

vdso=1: enable VDSO (the default)
Expand All @@ -6296,11 +6320,12 @@
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.rst.

video.brightness_switch_enabled= [0,1]
video.brightness_switch_enabled= [ACPI]
Format: [0|1]
If set to 1, on receiving an ACPI notify event
generated by hotkey, video driver will adjust brightness
level and then send out the event to user space through
the allocated input device; If set to 0, video driver
the allocated input device. If set to 0, video driver
will only send out the event without touching backlight
brightness level.
default: 1
Expand Down

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