cpufreq: use last policy after online for drivers with ->setpolicy

For cpufreq drivers which use setpolicy interface, after offline->online
the policy is set to default. This can be reproduced by setting the
default policy of intel_pstate or longrun to ondemand and then change to
"performance". After offline and online, the setpolicy will be called with
the policy=ondemand.

For drivers using governors this condition is handled by storing
last_governor, during offline and restoring during online. The same should
be done for drivers using setpolicy interface. Storing last_policy during
offline and restoring during online.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index a83c995a62dfed9173823289d4cc3bbd3199cf12..8412ce5f93a712a03bfa81df25bee238a299d242 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -976,10 +976,14 @@ static int cpufreq_init_policy(struct cpufreq_policy *policy)
 
        new_policy.governor = gov;
 
-       /* Use the default policy if its valid. */
-       if (cpufreq_driver->setpolicy)
-               cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
-
+       /* Use the default policy if there is no last_policy. */
+       if (cpufreq_driver->setpolicy) {
+               if (policy->last_policy)
+                       new_policy.policy = policy->last_policy;
+               else
+                       cpufreq_parse_governor(gov->name, &new_policy.policy,
+                                              NULL);
+       }
        /* set default policy */
        return cpufreq_set_policy(policy, &new_policy);
 }
@@ -1330,6 +1334,8 @@ static void cpufreq_offline_prepare(unsigned int cpu)
                if (has_target())
                        strncpy(policy->last_governor, policy->governor->name,
                                CPUFREQ_NAME_LEN);
+               else
+                       policy->last_policy = policy->policy;
        } else if (cpu == policy->cpu) {
                /* Nominate new CPU */
                policy->cpu = cpumask_any(policy->cpus);

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ef4c5b1a860f5c610c0ee4646aa2b729aa81f71a..177c7680c1a8a81bcc942497ee228c148fbf5a0b 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -77,6 +77,7 @@ struct cpufreq_policy {
        unsigned int            suspend_freq; /* freq to set during suspend */
 
        unsigned int            policy; /* see above */
+       unsigned int            last_policy; /* policy before unplug */
        struct cpufreq_governor *governor; /* see below */
        void                    *governor_data;
        bool                    governor_enabled; /* governor start/stop flag */