[PATCH] cpufreq: use last policy after online

Srinivas Pandruvada
2015-12-02T00:53:24Z

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>
---
drivers/cpufreq/cpufreq.c | 14 ++++++++++----
include/linux/cpufreq.h | 1 +
2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index a83c995..8412ce5 100644
--- 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 ef4c5b1..177c768 100644
--- 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 */
--
1.9.3