Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH] PM / Domains: Do not stop devices after restoring their states | Date | Mon, 28 May 2012 01:58:45 +0200 |
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From: Rafael J. Wysocki <rjw@sisk.pl>
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> --- drivers/base/power/domain.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-)
Index: linux/drivers/base/power/domain.c =================================================================== --- linux.orig/drivers/base/power/domain.c +++ linux/drivers/base/power/domain.c @@ -363,19 +363,16 @@ static void __pm_genpd_restore_device(st { 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; } /** @@ -638,7 +635,7 @@ static int pm_genpd_runtime_resume(struc /* 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); @@ -671,9 +668,6 @@ static int pm_genpd_runtime_resume(struc wake_up_all(&genpd->status_wait_queue); mutex_unlock(&genpd->lock); - out: - genpd_start_dev(genpd, dev); - return 0; }
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