PM / Domains: Don't measure ->start|stop() latency in system PM callbacks

Measure latency does by itself contribute to an increased latency, thus we
should avoid it when it isn't needed.

Genpd measures latencies in the system PM phase for the ->start|stop()
callbacks and is thus affecting the system PM suspend/resume time.
Moreover these latencies are validated only at runtime PM suspend/resume.

To this reasoning, let's decide to leave these measurements out of the
system PM phase. There should be plenty of occasions during runtime PM to
perform these measurements anyway.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -90,8 +90,12 @@ static struct generic_pm_domain *dev_to_genpd(struct device *dev)
 	return pd_to_genpd(dev->pm_domain);
 }
 
-static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
+static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev,
+			bool timed)
 {
+	if (!timed)
+		return GENPD_DEV_CALLBACK(genpd, int, stop, dev);
+
 	return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
 					stop_latency_ns, "stop");
 }
@@ -434,7 +438,7 @@ static int pm_genpd_runtime_suspend(struct device *dev)
 	if (ret)
 		return ret;
 
-	ret = genpd_stop_dev(genpd, dev);
+	ret = genpd_stop_dev(genpd, dev, true);
 	if (ret) {
 		genpd_restore_dev(genpd, dev, true);
 		return ret;
@@ -779,7 +783,7 @@ static int pm_genpd_suspend_noirq(struct device *dev)
 	    || (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev)))
 		return 0;
 
-	genpd_stop_dev(genpd, dev);
+	genpd_stop_dev(genpd, dev, false);
 
 	/*
 	 * Since all of the "noirq" callbacks are executed sequentially, it is
@@ -820,7 +824,7 @@ static int pm_genpd_resume_noirq(struct device *dev)
 	pm_genpd_sync_poweron(genpd, true);
 	genpd->suspended_count--;
 
-	return genpd_start_dev(genpd, dev, true);
+	return genpd_start_dev(genpd, dev, false);
 }
 
 /**
@@ -928,7 +932,7 @@ static int pm_genpd_freeze_noirq(struct device *dev)
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	return genpd->suspend_power_off ? 0 : genpd_stop_dev(genpd, dev);
+	return genpd->suspend_power_off ? 0 : genpd_stop_dev(genpd, dev, false);
 }
 
 /**
@@ -948,7 +952,8 @@ static int pm_genpd_thaw_noirq(struct device *dev)
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	return genpd->suspend_power_off ? 0 : genpd_start_dev(genpd, dev, true);
+	return genpd->suspend_power_off ?
+		0 : genpd_start_dev(genpd, dev, false);
 }
 
 /**
@@ -1042,7 +1047,7 @@ static int pm_genpd_restore_noirq(struct device *dev)
 
 	pm_genpd_sync_poweron(genpd, true);
 
-	return genpd_start_dev(genpd, dev, true);
+	return genpd_start_dev(genpd, dev, false);
 }
 
 /**