1 files changed, 28 insertions, 6 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 2f6a73c01b71..f7b9d6fce123 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -763,6 +763,8 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
         init_completion(&policy->kobj_unregister);
         INIT_WORK(&policy->update, handle_update);
 
+        /* Set governor before ->init, so that driver could check it */
+        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
         /* call driver. From then on the cpufreq must be able
          * to accept all calls to ->verify and ->setpolicy for this CPU
          */
@@ -1109,12 +1111,7 @@ unsigned int cpufreq_quick_get(unsigned int cpu)
         unsigned int ret_freq = 0;
 
         if (policy) {
-                if (unlikely(lock_policy_rwsem_read(cpu)))
-                        return ret_freq;
-
                 ret_freq = policy->cur;
-
-                unlock_policy_rwsem_read(cpu);
                 cpufreq_cpu_put(policy);
         }
 
@@ -1483,6 +1480,31 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 {
         int ret;
 
+        /* Only must be defined when default governor is known to have latency
+           restrictions, like e.g. conservative or ondemand.
+           That this is the case is already ensured in Kconfig
+        */
+#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
+        struct cpufreq_governor *gov = &cpufreq_gov_performance;
+#else
+        struct cpufreq_governor *gov = NULL;
+#endif
+
+        if (policy->governor->max_transition_latency &&
+            policy->cpuinfo.transition_latency >
+            policy->governor->max_transition_latency) {
+                if (!gov)
+                        return -EINVAL;
+                else {
+                        printk(KERN_WARNING "%s governor failed, too long"
+                               " transition latency of HW, fallback"
+                               " to %s governor\n",
+                               policy->governor->name,
+                               gov->name);
+                        policy->governor = gov;
+                }
+        }
+
         if (!try_module_get(policy->governor->owner))
                 return -EINVAL;
 
@@ -1703,7 +1725,7 @@ int cpufreq_update_policy(unsigned int cpu)
 }
 EXPORT_SYMBOL(cpufreq_update_policy);
 
-static int cpufreq_cpu_callback(struct notifier_block *nfb,
+static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
                                         unsigned long action, void *hcpu)
 {
         unsigned int cpu = (unsigned long)hcpu;