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authorViresh Kumar <viresh.kumar@linaro.org>2013-07-02 16:36:28 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-07-04 13:12:44 +0200
commit266c13d767be61a17d8e6f2310b9b7c46278273b (patch)
tree924a27434d5846f69b541012494d6ea1f2cb10cf /drivers/cpufreq
parentf991fae5c6d42dfc5029150b05a78cf3f6c18cc9 (diff)
cpufreq: Fix serialization of frequency transitions
Commit 7c30ed ("cpufreq: make sure frequency transitions are serialized") interacts poorly with systems that have a single core freqency for all cores. On such systems we have a single policy for all cores with several CPUs. When we do a frequency transition the governor calls the pre and post change notifiers which causes cpufreq_notify_transition() per CPU. Since the policy is the same for all of them all CPUs after the first and the warnings added are generated by checking a per-policy flag the warnings will be triggered for all cores after the first. Fix this by allowing notifier to be called for n times. Where n is the number of cpus in policy->cpus. Reported-and-tested-by: Mark Brown <broonie@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 6a015ada5285..0937b8d6c2a4 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -312,11 +312,12 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
switch (state) {
case CPUFREQ_PRECHANGE:
- if (WARN(policy->transition_ongoing,
+ if (WARN(policy->transition_ongoing ==
+ cpumask_weight(policy->cpus),
"In middle of another frequency transition\n"))
return;
- policy->transition_ongoing = true;
+ policy->transition_ongoing++;
/* detect if the driver reported a value as "old frequency"
* which is not equal to what the cpufreq core thinks is
@@ -341,7 +342,7 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
"No frequency transition in progress\n"))
return;
- policy->transition_ongoing = false;
+ policy->transition_ongoing--;
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,