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>
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 @@
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 @@
"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,