summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorViresh Kumar <viresh.kumar@linaro.org>2015-07-10 01:36:27 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-10 01:36:27 +0200
commit35afd02e30d6368073df604920c4ea7cddadf5d0 (patch)
treea3ee1383e9cd2d6c1f50650617d155123b718090
parentLinux 4.2-rc1 (diff)
downloadlinux-35afd02e30d6368073df604920c4ea7cddadf5d0.tar.xz
linux-35afd02e30d6368073df604920c4ea7cddadf5d0.zip
cpufreq: Initialize the governor again while restoring policy
When all CPUs of a policy are hot-unplugged, we EXIT the governor but don't mark policy->governor as NULL. This was done in order to keep last used governor's information intact in sysfs, while the CPUs are offline. But we also need to clear policy->governor when restoring the policy. Because policy->governor still points to the last governor while policy is restored, following sequence of event happens: - cpufreq_init_policy() called while restoring policy - find_governor() matches last_governor string for present governors and returns last used governor's pointer, say ondemand. policy->governor already has the same address, unless the governor was removed in between. - cpufreq_set_policy() is called with both old/new policies governor set as ondemand. - Because governors matched, we skip governor initialization and return after calling __cpufreq_governor(CPUFREQ_GOV_LIMITS). Because the governor wasn't initialized for this policy, it returned -EBUSY. - cpufreq_init_policy() exits the policy on this error, but doesn't destroy it properly (should be fixed separately). - And so we enter a scenario where the policy isn't completely initialized but used. Fix this by setting policy->governor to NULL while restoring the policy. Reported-and-tested-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org> Reported-and-tested-by: "Jon Medhurst (Tixy)" <tixy@linaro.org> Reported-and-tested-by: Steven Rostedt <rostedt@goodmis.org> Fixes: 18bf3a124ef8 (cpufreq: Mark policy->governor = NULL for inactive policies) Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/cpufreq/cpufreq.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index b612411655f9..2c22e3902e72 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1132,6 +1132,7 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
down_write(&policy->rwsem);
policy->cpu = cpu;
+ policy->governor = NULL;
up_write(&policy->rwsem);
}