cpufreq: Abort cpufreq_update_current_freq() for cpufreq_suspended set

rafaeljw · rafaeljw · commit c9d9c929e674 · 2016-04-18T23:47:42.000+02:00
Since governor operations are generally skipped if cpufreq_suspended is set, cpufreq_start_governor() should do nothing in that case. That function is called in the cpufreq_online() path, and may also be called from cpufreq_offline() in some cases, which are invoked by the nonboot CPUs disabing/enabling code during system suspend to RAM and resume. That happens when all devices have been suspended, so if the cpufreq driver relies on things like I2C to get the current frequency, it may not be ready to do that then. To prevent problems from happening for this reason, make cpufreq_update_current_freq(), which is the only function invoked by cpufreq_start_governor() that doesn't check cpufreq_suspended already, return 0 upfront if cpufreq_suspended is set. Fixes: 3bbf8fe (cpufreq: Always update current frequency before startig governor) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
@@ -1491,6 +1491,9 @@ static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
 {
 	unsigned int new_freq;
 
+	if (cpufreq_suspended)
+		return 0;
+
 	new_freq = cpufreq_driver->get(policy->cpu);
 	if (!new_freq)
 		return 0;

Original file line number	Diff line number	Diff line change
`@@ -1491,6 +1491,9 @@ static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)`
`1491`	`1491`	`{`
`1492`	`1492`	`unsigned int new_freq;`
`1493`	`1493`
	`1494`	`+ if (cpufreq_suspended)`
	`1495`	`+ return 0;`
	`1496`	`+`
`1494`	`1497`	`new_freq = cpufreq_driver->get(policy->cpu);`
`1495`	`1498`	`if (!new_freq)`
`1496`	`1499`	`return 0;`