Commit 87cbde8d authored Sep 28, 2017 by Rafael J. Wysocki

PM / s2idle: Invoke the ->wake() platform callback earlier



The role of the ->wake() platform callback for suspend-to-idle is to
deal with possible spurious wakeups, among other things.  The ACPI
implementation of it, acpi_s2idle_wake(), additionally checks the
conditions for entering the Low Power S0 Idle state by the platform
and reports the ones that have not been met.

However, the ->wake() platform callback is invoked after calling
dpm_noirq_resume_devices(), which means that the power states of some
devices may have changed since s2idle_enter() returned, so some unmet
Low Power S0 Idle conditions may be reported incorrectly as a result
of that.

To avoid these false positives, reorder the invocations of the
dpm_noirq_resume_devices() routine and the ->wake() platform callback
in s2idle_loop().

Fixes: 726fb6b4 (ACPI / PM: Check low power idle constraints for debug only)
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent e19b205b

kernel/power/suspend.c

+11 −7

Original line number	Diff line number	Diff line
		@@ -120,22 +120,26 @@ static void s2idle_loop(void)
		* frozen processes + suspended devices + idle processors.
		* Thus s2idle_enter() should be called right after
		* all devices have been suspended.
		*
		* Wakeups during the noirq suspend of devices may be spurious,
		* so prevent them from terminating the loop right away.
		*/
		error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
		if (!error)
		s2idle_enter();
		else if (error == -EBUSY && pm_wakeup_pending())
		error = 0;

		dpm_noirq_resume_devices(PMSG_RESUME);
		if (error && (error != -EBUSY \|\| !pm_wakeup_pending())) {
		dpm_noirq_end();
		break;
		}

		if (s2idle_ops && s2idle_ops->wake)
		if (!error && s2idle_ops && s2idle_ops->wake)
		s2idle_ops->wake();

		dpm_noirq_resume_devices(PMSG_RESUME);

		dpm_noirq_end();

		if (error)
		break;

		if (s2idle_ops && s2idle_ops->sync)
		s2idle_ops->sync();