cpufreq: Don't call __cpufreq_governor() for drivers without target()

Some cpufreq drivers implement their own governor and so don't need
us to call generic governors interface via __cpufreq_governor(). Few
recent commits haven't obeyed this law well and we saw some
regressions.

This patch is an attempt to fix the above issue.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 3564947ea7ac..a6f65954b0ab 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -858,13 +858,18 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
                                   struct device *dev)
 {
         struct cpufreq_policy *policy;
-        int ret = 0;
+        int ret = 0, has_target = 0;
         unsigned long flags;
 
         policy = cpufreq_cpu_get(sibling);
         WARN_ON(!policy);
 
-        __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+        rcu_read_lock();
+        has_target = !!rcu_dereference(cpufreq_driver)->target;
+        rcu_read_unlock();
+
+        if (has_target)
+                __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
 
         lock_policy_rwsem_write(sibling);
 
@@ -877,8 +882,10 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
 
         unlock_policy_rwsem_write(sibling);
 
-        __cpufreq_governor(policy, CPUFREQ_GOV_START);
-        __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+        if (has_target) {
+                __cpufreq_governor(policy, CPUFREQ_GOV_START);
+                __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+        }
 
         ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
         if (ret) {
@@ -1146,7 +1153,8 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif
 
         /* If cpu is last user of policy, free policy */
         if (cpus == 1) {
-                __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+                if (has_target)
+                        __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
 
                 lock_policy_rwsem_read(cpu);
                 kobj = &data->kobj;