[PATCH 5/6] PM / domain: Save/restore performance state at runtime suspend/resume

[Viresh Kumar]

With runtime PM, the devices get suspended while the system is up and
running in order to save power. At such times, it is important to
re-evaluate the required performance state of the domain, in order to
choose a lower state if possible.

This patch updates the genpd suspend/resume callbacks to do that.

Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
 drivers/base/power/domain.c | 19 +++++++++++++++++--
 include/linux/pm_domain.h   |  1 +
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index f460be4ca5f7..ef4062927713 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -576,7 +576,8 @@ static int genpd_runtime_suspend(struct device *dev)
 {
        struct generic_pm_domain *genpd;
        bool (*suspend_ok)(struct device *__dev);
-       struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+       struct generic_pm_domain_data *pd_data = dev_gpd_data(dev);
+       struct gpd_timing_data *td = &pd_data->td;
        bool runtime_pm = pm_runtime_enabled(dev);
        ktime_t time_start;
        s64 elapsed_ns;
@@ -633,7 +634,14 @@ static int genpd_runtime_suspend(struct device *dev)
                return 0;
 
        genpd_lock(genpd);
+
+       /* Re-evaluate performance state of the domain */
+       pd_data->cached_performance_state = pd_data->performance_state;
+       pd_data->performance_state = 0;
+       update_domain_performance_state(genpd);
+
        genpd_poweroff(genpd, false);
+
        genpd_unlock(genpd);
 
        return 0;
@@ -650,7 +658,8 @@ static int genpd_runtime_suspend(struct device *dev)
 static int genpd_runtime_resume(struct device *dev)
 {
        struct generic_pm_domain *genpd;
-       struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+       struct generic_pm_domain_data *pd_data = dev_gpd_data(dev);
+       struct gpd_timing_data *td = &pd_data->td;
        bool runtime_pm = pm_runtime_enabled(dev);
        ktime_t time_start;
        s64 elapsed_ns;
@@ -673,7 +682,13 @@ static int genpd_runtime_resume(struct device *dev)
        }
 
        genpd_lock(genpd);
+
        ret = genpd_poweron(genpd, 0);
+
+       /* Re-evaluate performance state of the domain */
+       pd_data->performance_state = pd_data->cached_performance_state;
+       update_domain_performance_state(genpd);
+
        genpd_unlock(genpd);
 
        if (ret)
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index d994ad5ba1c0..69b453d44adb 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -122,6 +122,7 @@ struct generic_pm_domain_data {
        struct notifier_block nb;
        struct notifier_block perf_nb;
        unsigned int performance_state;
+       unsigned int cached_performance_state;
 };
 
 #ifdef CONFIG_PM_GENERIC_DOMAINS
-- 
2.7.1.410.g6faf27b