Commit Graph

31 Commits

Author SHA1 Message Date
Thomas Renninger
e2f74f355e [ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface
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 <venkatesh.pallipadi@intel.com>
CC: Len Brown <lenb@kernel.org>
CC: davej@codemonkey.org.uk
CC: linux@dominikbrodowski.net

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-11-24 13:33:34 -05:00
Mark Brown
bbe237aafe [CPUFREQ] Document units for transition latency
They're documented in the header but not in Documentation.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-11-24 13:33:34 -05:00
Naga Chumbalkar
da470db16c [CPUFREQ] update Doc for cpuinfo_cur_freq and scaling_cur_freq
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 <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-09-01 12:45:09 -04:00
Chumbalkar Nagananda
51555c0e91 [CPUFREQ] minor correction to cpu-freq documentation
I have been reading the documentation for cpufreq closely. Found a couple of
minor errors in the Documentation.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-06-15 11:49:42 -04:00
Thomas Renninger
4f4d1ad6ee [CPUFREQ] Only set sampling_rate_max deprecated, sampling_rate_min is useful
Update the documentation accordingly.
Cleanup and use printk_once.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-06-15 11:49:41 -04:00
Thomas Renninger
112124ab0a [CPUFREQ] ondemand/conservative: sanitize sampling_rate restrictions
Limit sampling rate to transition_latency * 100 or kernel limits.
If sampling_rate is tried to be set too low, set the lowest allowed value.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-24 22:47:31 -05:00
Thomas Renninger
9411b4ef7f [CPUFREQ] ondemand/conservative: deprecate sampling_rate{min,max}
The same info can be obtained via the transition_latency sysfs file

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-24 22:47:31 -05:00
Thomas Renninger
ed12978453 [CPUFREQ] Introduce /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_transition_latency
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 <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-02-24 22:47:31 -05:00
Thomas Renninger
62663ea822 ACPI: cpufreq: Remove deprecated /proc/acpi/processor/../performance proc entries
They were long enough set deprecated...

Update Documentation/cpu-freq/users-guide.txt:
The deprecated files listed there seen not to exist for some time anymore
already.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2009-02-04 00:12:24 -05:00
Paul Mundt
8a655053ca doc: Update sh cpufreq documentation.
The sh cpufreq driver is no longer limited to just the SH-3 and SH-4,
update the documentation to reflect this fact accordingly.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:44:47 +09:00
Robin Getz
121fe86bdf [CPUFREQ] Documentation: Add Blackfin to list of supported processors
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2008-11-25 13:38:29 -05:00
Németh Márton
8d59225720 [CPUFREQ] correct broken links and email addresses
Replace the no longer working links and email address in the
documentation and in source code.

Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09 13:52:40 -04:00
Matt LaPlante
d91958815d Documentation cleanup: trivial misspelling, punctuation, and grammar corrections.
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:06 -07:00
Dave Jones
da8395be0b [CPUFREQ] Remove documentation of removed ondemand tunable.
sampling_down_factor was removed in ccb2fe209d
back in June 2006.

Signed-off-by: Dave Jones <davej@redhat.com>
2008-05-20 22:13:09 -04:00
Darrick J. Wong
605400a8ab [CPUFREQ] document the currently undocumented parts of the sysfs interface
There is a description of some of the sysfs files.  However, there are some
that are not mentioned in the documentation, so add them to the user's guide.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2008-04-28 16:27:08 -04:00
Russell King
9e2697ff37 [ARM] pxa: add cpufreq support
There have been patches hanging around for ages to add support for
cpufreq to PXA255 processors.  It's about time we applied one.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-01-26 15:07:52 +00:00
Matt LaPlante
a982ac06b0 misc doc and kconfig typos
Fix various typos in kernel docs and Kconfigs, 2.6.21-rc4.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-05-09 08:58:15 +02:00
Dave Jones
c4366889dd Merge ../linus
Conflicts:

	drivers/cpufreq/cpufreq.c
2006-12-12 17:41:41 -05:00
Matt LaPlante
5d3f083d8f Fix typos in /Documentation : Misc
This patch fixes typos in various Documentation txts. The patch addresses some
misc words.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-11-30 05:21:10 +01:00
Dominik Brodowski
eff0df65da [CPUFREQ] Documentation fix
Fix reference to where the code actually is. Noted by Hero Wanders.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-15 19:57:10 -04:00
Matt LaPlante
53cb47268e Fix typos in Documentation/: 'S'
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letter 'S'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03 22:55:17 +02:00
Matt LaPlante
992caacf11 Fix typos in Documentation/: 'N'-'P'
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'N'-'P'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03 22:52:05 +02:00
Matt LaPlante
2fe0ae78c6 Fix typos in Documentation/: 'H'-'M'
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'H'-'M'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03 22:50:39 +02:00
Matt LaPlante
a2ffd27516 Fix typos in Documentation/: 'F'-'G'
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'F'-'G'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-03 22:49:15 +02:00
Mattia Dongili
9c9a43ed27 [CPUFREQ] return error when failing to set minfreq
I just stumbled on this bug/feature, this is how to reproduce it:

# echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
# echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
# cpufreq-info -p
450000 450000 powersave
# echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq ; echo $?
0
# cpufreq-info -p
450000 450000 powersave

Here it is. The kernel refuses to set a min_freq higher than the
max_freq but it allows a max_freq lower than min_freq (lowering min_freq
also).

This behaviour is pretty straightforward (but undocumented) and it
doesn't return an error altough failing to accomplish the requested
action (set min_freq).
The problem (IMO) is basically that userspace is not allowed to set a
full policy atomically while the kernel always does that thus it must
enforce an ordering on operations.

The attached patch returns -EINVAL if trying to increase frequencies
starting from scaling_min_freq and documents the correct ordering of writes.

Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Dominik Brodowski <linux at dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>

--
2006-07-31 18:37:05 -04:00
Erik Mouw
4c41251e31 [CPUFREQ] Update LART site URL
Update LART site URL.

The LART website moved to http://www.lartmaker.nl/. This patch
updates the URL in CpuFreq specific files.

Signed-off-by: Erik Mouw <erik@bitwizard.nl>
Signed-off-by: Dave Jones <davej@redhat.com>
2006-04-03 07:25:54 -05:00
Alexander Clouter
537208c807 [PATCH] cpufreq: documentation for 'ondemand' and 'conservative'
Added a more verbose entry for the 'ondemend' governor and an entry for the
'conservative' governor to the documentation.

Signed-off-by: Alexander Clouter <alex-kernel@digriz.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2005-12-01 01:23:23 -08:00
Tobias Klauser
d533f67185 [PATCH] Spelling fixes for Documentation/
The attached patch fixes the following spelling errors in Documentation/
        - double "the"
        - Several misspellings of function/functionality
        - infomation
        - memeory
        - Recieved
        - wether
and possibly others which I forgot ;-)
Trailing whitespaces on the same line as the typo are also deleted.

Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 10:06:28 -07:00
Nico Golde
594dd2c981 [PATCH] cpufreq: governors documentation fixes
I corrected a small error and enhanced the govenor.txt file with the
ondemand daemon because the kernel configs link to the documentation but
ondemand wasn't documentated.  Feel free to include the patch in the
attachment.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:55 -07:00
Venkatesh Pallipadi
21e3024cbd [PATCH] cpufreq-stats driver documentation
Documentation for cpufreq stats.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2005-05-31 19:04:05 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00