From: Viresh Kumar Date: Tue, 2 Jul 2013 11:06:28 +0000 (+0530) Subject: cpufreq: Fix serialization of frequency transitions X-Git-Tag: upstream/snapshot3+hdmi~4715^2~2^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=266c13d767be61a17d8e6f2310b9b7c46278273b;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git 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 Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 6a015ad..0937b8d 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, diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 4d7390b..90d5a15 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -119,7 +119,7 @@ struct cpufreq_policy { struct kobject kobj; struct completion kobj_unregister; - bool transition_ongoing; /* Tracks transition status */ + int transition_ongoing; /* Tracks transition status */ }; #define CPUFREQ_ADJUST (0)