Commit a4630c61 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Rafael J. Wysocki
Browse files

PM / Domains: Skip timings during syscore suspend/resume 



The PM Domain code uses ktime_get() to perform various latency
measurements.  However, if ktime_get() is called while timekeeping is
suspended, the following warning is printed:

    WARNING: CPU: 0 PID: 1340 at kernel/time/timekeeping.c:576 ktime_get+0x3

This happens when resuming the PM Domain that contains the clock events
source, which calls pm_genpd_syscore_poweron(). Chain of operations is:

    timekeeping_resume()
    {
	clockevents_resume()
	    sh_cmt_clock_event_resume()
		pm_genpd_syscore_poweron()
		    pm_genpd_sync_poweron()
			genpd_syscore_switch()
			    genpd_power_on()
				ktime_get(), but timekeeping_suspended == 1
	...
	timekeeping_suspended = 0;
    }

Fix this by adding a "timed" parameter to genpd_power_{on,off}() and
pm_genpd_sync_power{off,on}(), to indicate whether latency measurements
are allowed.  This parameter is passed as false in
genpd_syscore_switch() (i.e. during syscore suspend/resume), and true in
all other cases.

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 0f57d867

drivers/base/power/domain.c

+26 −16
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ static void genpd_recalc_cpu_exit_latency(struct generic_pm_domain *genpd) 
	genpd->cpuidle_data->idle_state->exit_latency = usecs64;

}



static int genpd_power_on(struct generic_pm_domain *genpd)

static int genpd_power_on(struct generic_pm_domain *genpd, bool timed)

{

	ktime_t time_start;

	s64 elapsed_ns;
@@ -190,6 +190,9 @@ static int genpd_power_on(struct generic_pm_domain *genpd) 
	if (!genpd->power_on)

		return 0;



	if (!timed)

		return genpd->power_on(genpd);



	time_start = ktime_get();

	ret = genpd->power_on(genpd);

	if (ret)
@@ -208,7 +211,7 @@ static int genpd_power_on(struct generic_pm_domain *genpd) 
	return ret;

}



static int genpd_power_off(struct generic_pm_domain *genpd)

static int genpd_power_off(struct generic_pm_domain *genpd, bool timed)

{

	ktime_t time_start;

	s64 elapsed_ns;
@@ -217,6 +220,9 @@ static int genpd_power_off(struct generic_pm_domain *genpd) 
	if (!genpd->power_off)

		return 0;



	if (!timed)

		return genpd->power_off(genpd);



	time_start = ktime_get();

	ret = genpd->power_off(genpd);

	if (ret == -EBUSY)
@@ -305,7 +311,7 @@ static int __pm_genpd_poweron(struct generic_pm_domain *genpd) 
		}

	}



	ret = genpd_power_on(genpd);

	ret = genpd_power_on(genpd, true);

	if (ret)

		goto err;
@@ -615,7 +621,7 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd) 
		 * the pm_genpd_poweron() restore power for us (this shouldn't

		 * happen very often).

		 */

		ret = genpd_power_off(genpd);

		ret = genpd_power_off(genpd, true);

		if (ret == -EBUSY) {

			genpd_set_active(genpd);

			goto out;
@@ -827,6 +833,7 @@ static bool genpd_dev_active_wakeup(struct generic_pm_domain *genpd, 
/**

 * pm_genpd_sync_poweroff - Synchronously power off a PM domain and its masters.

 * @genpd: PM domain to power off, if possible.

 * @timed: True if latency measurements are allowed.

 *

 * Check if the given PM domain can be powered off (during system suspend or

 * hibernation) and do that if so.  Also, in that case propagate to its masters.
@@ -836,7 +843,8 @@ static bool genpd_dev_active_wakeup(struct generic_pm_domain *genpd, 
 * executed sequentially, so it is guaranteed that it will never run twice in

 * parallel).

 */

static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd)

static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd,

				   bool timed)

{

	struct gpd_link *link;
@@ -847,26 +855,28 @@ static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd) 
	    || atomic_read(&genpd->sd_count) > 0)

		return;



	genpd_power_off(genpd);

	genpd_power_off(genpd, timed);



	genpd->status = GPD_STATE_POWER_OFF;



	list_for_each_entry(link, &genpd->slave_links, slave_node) {

		genpd_sd_counter_dec(link->master);

		pm_genpd_sync_poweroff(link->master);

		pm_genpd_sync_poweroff(link->master, timed);

	}

}



/**

 * pm_genpd_sync_poweron - Synchronously power on a PM domain and its masters.

 * @genpd: PM domain to power on.

 * @timed: True if latency measurements are allowed.

 *

 * This function is only called in "noirq" and "syscore" stages of system power

 * transitions, so it need not acquire locks (all of the "noirq" callbacks are

 * executed sequentially, so it is guaranteed that it will never run twice in

 * parallel).

 */

static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd)

static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd,

				  bool timed)

{

	struct gpd_link *link;
@@ -874,11 +884,11 @@ static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd) 
		return;



	list_for_each_entry(link, &genpd->slave_links, slave_node) {

		pm_genpd_sync_poweron(link->master);

		pm_genpd_sync_poweron(link->master, timed);

		genpd_sd_counter_inc(link->master);

	}



	genpd_power_on(genpd);

	genpd_power_on(genpd, timed);



	genpd->status = GPD_STATE_ACTIVE;

}
@@ -1056,7 +1066,7 @@ static int pm_genpd_suspend_noirq(struct device *dev) 
	 * the same PM domain, so it is not necessary to use locking here.

	 */

	genpd->suspended_count++;

	pm_genpd_sync_poweroff(genpd);

	pm_genpd_sync_poweroff(genpd, true);



	return 0;

}
@@ -1086,7 +1096,7 @@ static int pm_genpd_resume_noirq(struct device *dev) 
	 * guaranteed that this function will never run twice in parallel for

	 * the same PM domain, so it is not necessary to use locking here.

	 */

	pm_genpd_sync_poweron(genpd);

	pm_genpd_sync_poweron(genpd, true);

	genpd->suspended_count--;



	return genpd_start_dev(genpd, dev);
@@ -1300,7 +1310,7 @@ static int pm_genpd_restore_noirq(struct device *dev) 
			 * If the domain was off before the hibernation, make

			 * sure it will be off going forward.

			 */

			genpd_power_off(genpd);

			genpd_power_off(genpd, true);



			return 0;

		}
@@ -1309,7 +1319,7 @@ static int pm_genpd_restore_noirq(struct device *dev) 
	if (genpd->suspend_power_off)

		return 0;



	pm_genpd_sync_poweron(genpd);

	pm_genpd_sync_poweron(genpd, true);



	return genpd_start_dev(genpd, dev);

}
@@ -1367,9 +1377,9 @@ static void genpd_syscore_switch(struct device *dev, bool suspend) 


	if (suspend) {

		genpd->suspended_count++;

		pm_genpd_sync_poweroff(genpd);

		pm_genpd_sync_poweroff(genpd, false);

	} else {

		pm_genpd_sync_poweron(genpd);

		pm_genpd_sync_poweron(genpd, false);

		genpd->suspended_count--;

	}

}

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