diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index f8c28607ccd6..43cf60832468 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -49,6 +49,7 @@ static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); #endif static DEFINE_RWLOCK(cpufreq_driver_lock); +static DEFINE_MUTEX(cpufreq_governor_lock); /* * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure @@ -1635,6 +1636,21 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, pr_debug("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event); + + mutex_lock(&cpufreq_governor_lock); + if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) || + (policy->governor_enabled && (event == CPUFREQ_GOV_START))) { + mutex_unlock(&cpufreq_governor_lock); + return -EBUSY; + } + + if (event == CPUFREQ_GOV_STOP) + policy->governor_enabled = false; + else if (event == CPUFREQ_GOV_START) + policy->governor_enabled = true; + + mutex_unlock(&cpufreq_governor_lock); + ret = policy->governor->governor(policy, event); if (!ret) { @@ -1642,6 +1658,14 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->governor->initialized++; else if (event == CPUFREQ_GOV_POLICY_EXIT) policy->governor->initialized--; + } else { + /* Restore original values */ + mutex_lock(&cpufreq_governor_lock); + if (event == CPUFREQ_GOV_STOP) + policy->governor_enabled = true; + else if (event == CPUFREQ_GOV_START) + policy->governor_enabled = false; + mutex_unlock(&cpufreq_governor_lock); } /* we keep one module reference alive for |