[PATCH 1/3 v3] Docs: admin/kernel-parameters: edit a few boot options

From: Randy Dunlap
Date: Sun Apr 03 2022 - 01:48:57 EST

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@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: sparclinux@xxxxxxxxxxxxxxx
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
v3: add trace_clock= specifics (Steven)
v2: drop "smt-enabled" for arch/powerpc/ (Michael)

Documentation/admin-guide/kernel-parameters.txt | 47 ++++++++++----
1 file changed, 36 insertions(+), 11 deletions(-)

--- linux-next-20220331.orig/Documentation/admin-guide/kernel-parameters.txt
+++ linux-next-20220331/Documentation/admin-guide/kernel-parameters.txt
@@ -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
@@ -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]
@@ -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.
@@ -5774,8 +5774,9 @@
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)

@@ -5821,7 +5822,8 @@

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
@@ -5908,6 +5910,28 @@
[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.
[FTRACE] Set and start specified trace events in order
to facilitate early boot debugging. The event-list is a
@@ -5930,7 +5954,7 @@
See also Documentation/trace/ftrace.rst "trace options"

- 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
@@ -5952,7 +5976,7 @@
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
@@ -6301,7 +6325,7 @@
HIGHMEM regardless of setting

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

vdso=1: enable VDSO (the default)
@@ -6327,11 +6351,12 @@
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