kernel/git/stable/linux.git/Documentation/cpu-freq/user-guide.txt, branch master

cpufreq: User/admin documentation update and consolidation

2017-03-13T23:08:42+00:00

The user/admin documentation of cpufreq is badly outdated. It conains stale and/or inaccurate information along with things that are not particularly useful. Also, some of the important pieces are missing from it. For this reason, add a new user/admin document for cpufreq containing current information to admin-guide and drop the old outdated .txt documents it is replacing. Since there will be more PM documents in admin-guide going forward, create a separate directory for them and put the cpufreq document in there right away. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Jonathan Corbet

Merge tag 'docs-4.11' of git://git.lwn.net/linux

2017-02-23T02:51:29+00:00

Pull documentation updates from Jonathan Corbet: "A slightly quieter cycle for documentation this time around. Three more DocBook template files have been converted to RST; only 21 to go. There are various build improvements and the usual array of documentation improvements and fixes" * tag 'docs-4.11' of git://git.lwn.net/linux: (44 commits) docs / driver-api: Fix structure references in device_link.rst PM / docs: Fix structure references in device.rst Add a target to check broken external links in the Documentation Documentation: Fix linux-api list typo Documentation: DocBook/Makefile comment typo Improve sparse documentation Documentation: make Makefile.sphinx no-ops quieter Documentation: DMA-ISA-LPC.txt Documentation: input: fix path to input code definitions docs: Remove the copyright year from conf.py docs: Fix a warning in the Korean HOWTO.rst translation PM / sleep / docs: Convert PM notifiers document to reST PM / core / docs: Convert sleep states API document to reST PM / core: Update kerneldoc comments in pm.h doc-rst: Fix recursive make invocation from macros doc-rst: Delete output of failed dot-SVG conversion doc-rst: Break shell command sequences on failure Documentation/sphinx: make targets independent of Sphinx work for HAVE_SPHINX=0 doc-rst: fixed cleandoc target when used with O=dir Documentation/sphinx: prevent generation of .pyc files in the source tree ...

cpufreq: Documentation: Updates based on current code

2017-02-03T22:59:40+00:00

The cpufreq core has gone though lots of updates in recent times, but on many occasions the documentation wasn't updated along with the code. This patch tries to catchup the documentation with the code. Also add Rafael and Viresh as the contributors to the documentation. Based on a patch from Claudio Scordino. Signed-off-by: Claudio Scordino Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

Note that the POWER[89] processors are supported.

2017-01-04T21:35:34+00:00

Documentation: cpufreq: Update supported powernv processors Signed-off-by: Shilpasri G Bhat Acked-by: Viresh Kumar Signed-off-by: Jonathan Corbet

Documentation: cpufreq: delete duplicate description of sysfs interface 'scaling_driver'

2015-05-05T21:23:25+00:00

The file 'Documentation/cpu-freq/user-guide.txt' has duplicate description of sysfs interface 'scaling_driver'. [first] scaling_driver : this file shows what cpufreq driver is used to set the frequency on this CPU [second] scaling_driver : Hardware driver for cpufreq. Although this does not affect anything, I think we should only have one. so delete the second one because the first one is described in more detail. Signed-off-by: Wang Long Signed-off-by: Rafael J. Wysocki

cpufreq: Update Documentation for cpus and related_cpus

2013-02-01T23:01:16+00:00

Documentation related to cpus and related_cpus is confusing and not very clear. Over that CPUFreq core has seen much changes recently. Lets update documentation and comments for cpus and related_cpus. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

[ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface

2009-11-24T18:33:34+00:00

This interface is mainly intended (and implemented) for ACPI _PPC BIOS frequency limitations, but other cpufreq drivers can also use it for similar use-cases. Why is this needed: Currently it's not obvious why cpufreq got limited. People see cpufreq/scaling_max_freq reduced, but this could have happened by: - any userspace prog writing to scaling_max_freq - thermal limitations - hardware (_PPC in ACPI case) limitiations Therefore export bios_limit (in kHz) to: - Point the user that it's the BIOS (broken or intended) which limits frequency - Export it as a sysfs interface for userspace progs. While this was a rarely used feature on laptops, there will appear more and more server implemenations providing "Green IT" features like allowing the service processor to limit the frequency. People want to know about HW/BIOS frequency limitations. All ACPI P-state driven cpufreq drivers are covered with this patch: - powernow-k8 - powernow-k7 - acpi-cpufreq Tested with a patched DSDT which limits the first two cores (_PPC returns 1) via _PPC, exposed by bios_limit: # echo 2200000 >cpu2/cpufreq/scaling_max_freq # cat cpu*/cpufreq/scaling_max_freq 2600000 2600000 2200000 2200000 # #scaling_max_freq shows general user/thermal/BIOS limitations # cat cpu*/cpufreq/bios_limit 2600000 2600000 2800000 2800000 # #bios_limit only shows the HW/BIOS limitation CC: Pallipadi Venkatesh CC: Len Brown CC: davej@codemonkey.org.uk CC: linux@dominikbrodowski.net Signed-off-by: Thomas Renninger Signed-off-by: Dave Jones

[CPUFREQ] update Doc for cpuinfo_cur_freq and scaling_cur_freq

2009-09-01T16:45:09+00:00

I think the way "cpuinfo_cur_info" and "scaling_cur_info" are defined under ./Documentation/cpu-freq/user-guide.txt can be enhanced. Currently, they are both defined the same way: "Current speed/frequency" of the CPU, in KHz". Below is a patch that distinguishes one from the other. Regards, - naga - ----------------------------------------- Update description for "cpuinfo_cur_freq" and "scaling_cur_freq". Some of the wording is drawn from comments found in ./drivers/cpufreq/cpufreq.c: cpufreq_out_of_sync(): * @old_freq: CPU frequency the kernel thinks the CPU runs at * @new_freq: CPU frequency the CPU actually runs at Signed-off-by: Naga Chumbalkar Signed-off-by: Dave Jones

[CPUFREQ] minor correction to cpu-freq documentation

2009-06-15T15:49:42+00:00

I have been reading the documentation for cpufreq closely. Found a couple of minor errors in the Documentation. Signed-off-by: Naga Chumbalkar Signed-off-by: Dave Jones

[CPUFREQ] Introduce /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_transition_latency

2009-02-25T03:47:31+00:00

It's not only useful for the ondemand and conservative governors, but also for userspace daemons to know about the HW transition latency of the CPU. It is especially useful for userspace to know about this value when the ondemand or conservative governors are run. The sampling rate control value depends on it and for userspace being able to set sane tuning values there it has to know about the transition latency. Signed-off-by: Thomas Renninger Signed-off-by: Dave Jones