PM / Domains: Do not stop devices after restoring their states
While resuming a device belonging to a PM domain,
pm_genpd_runtime_resume() calls __pm_genpd_restore_device() to
restore its state, if necessary. The latter starts the device,
using genpd_start_dev(), restores its state, using
genpd_restore_dev(), and then stops it, using genpd_stop_dev().
However, this last operation is not necessary, because the
device is supposed to be operational after pm_genpd_runtime_resume()
has returned and because of it pm_genpd_runtime_resume() has to
call genpd_start_dev() once again for the "restored" device, which
is inefficient.
To make things more efficient, remove the call to genpd_stop_dev()
from __pm_genpd_restore_device() and the direct call to
genpd_start_dev() from pm_genpd_runtime_resume(). [Of course,
genpd_start_dev() still has to be called by it for devices with the
power.irq_safe flag set, because __pm_genpd_restore_device() is not
executed for them.]
This change has been tested on the SH7372 Mackerel board.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 49fdd40..da1d525 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -339,19 +339,16 @@
{
struct generic_pm_domain_data *gpd_data = to_gpd_data(pdd);
struct device *dev = pdd->dev;
+ bool need_restore = gpd_data->need_restore;
- if (!gpd_data->need_restore)
- return;
-
+ gpd_data->need_restore = false;
mutex_unlock(&genpd->lock);
genpd_start_dev(genpd, dev);
- genpd_restore_dev(genpd, dev);
- genpd_stop_dev(genpd, dev);
+ if (need_restore)
+ genpd_restore_dev(genpd, dev);
mutex_lock(&genpd->lock);
-
- gpd_data->need_restore = false;
}
/**
@@ -595,7 +592,7 @@
/* If power.irq_safe, the PM domain is never powered off. */
if (dev->power.irq_safe)
- goto out;
+ return genpd_start_dev(genpd, dev);
mutex_lock(&genpd->lock);
ret = __pm_genpd_poweron(genpd);
@@ -628,9 +625,6 @@
wake_up_all(&genpd->status_wait_queue);
mutex_unlock(&genpd->lock);
- out:
- genpd_start_dev(genpd, dev);
-
return 0;
}