This is a note to let you know that I've just added the patch titled
cpufreq: intel_pstate: Fix setting max_perf_pct in performance policy
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpufreq-intel_pstate-fix-setting-max_perf_pct-in-performance-policy.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 36b4bed5cd8f6e17019fa7d380e0836872c7b367 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali.rohar@xxxxxxxxx>
Date: Thu, 16 Oct 2014 01:16:51 +0200
Subject: cpufreq: intel_pstate: Fix setting max_perf_pct in performance policy
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From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali.rohar@xxxxxxxxx>
commit 36b4bed5cd8f6e17019fa7d380e0836872c7b367 upstream.
Code which changes policy to powersave changes also max_policy_pct based on
max_freq. Code which change max_perf_pct has upper limit base on value
max_policy_pct. When policy is changing from powersave back to performance
then max_policy_pct is not changed. Which means that changing max_perf_pct is
not possible to high values if max_freq was too low in powersave policy.
Test case:
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
800000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
3300000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
100
$ echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
$ echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
$ echo 20 > /sys/devices/system/cpu/intel_pstate/max_perf_pct
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
powersave
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
800000
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
20
$ echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
$ echo 3300000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
$ echo 100 > /sys/devices/system/cpu/intel_pstate/max_perf_pct
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
3300000
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
24
And now intel_pstate driver allows to set maximal value for max_perf_pct based
on max_policy_pct which is 24 for previous powersave max_freq 800000.
This patch will set default value for max_policy_pct when setting policy to
performance so it will allow to set also max value for max_perf_pct.
Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
Acked-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -745,6 +745,7 @@ static int intel_pstate_set_policy(struc
if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
limits.min_perf_pct = 100;
limits.min_perf = int_tofp(1);
+ limits.max_policy_pct = 100;
limits.max_perf_pct = 100;
limits.max_perf = int_tofp(1);
limits.no_turbo = 0;
Patches currently in stable-queue which might be from pali.rohar@xxxxxxxxx are
queue-3.17/cpufreq-intel_pstate-fix-setting-max_perf_pct-in-performance-policy.patch
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