Commit 6f16886b authored Jan 21, 2016 by Sudeep Holla Committed by Rafael J. Wysocki Jan 22, 2016

cpuidle: fix fallback mechanism for suspend to idle in absence of enter_freeze

Commit 51164251 "sched / idle: Drop default_idle_call() fallback
from call_cpuidle()" made find_deepest_state() return non-negative
value and check all the states with index > 0. Also as a result,
find_deepest_state() returns 0 even when enter_freeze callbacks are not
implemented and enter_freeze_proper() is called which ends up crashing
the kernel.

This patch updates the check for index > 0 in cpuidle_enter_freeze and
cpuidle_idle_call(when idle_should_freeze is true) to restore the
suspend-to-idle functionality in absence of enter_freeze callback.

Fixes: 51164251 "sched / idle: Drop default_idle_call() fallback from call_cpuidle()"
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 5bb1729c

drivers/cpuidle/cpuidle.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -153,7 +153,7 @@ int cpuidle_enter_freeze(struct cpuidle_driver drv, struct cpuidle_device dev)
		* be frozen safely.
		*/
		index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
		if (index >= 0)
		if (index > 0)
		enter_freeze_proper(drv, dev, index);

		return index;

kernel/sched/idle.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -162,7 +162,7 @@ static void cpuidle_idle_call(void)
		*/
		if (idle_should_freeze()) {
		entered_state = cpuidle_enter_freeze(drv, dev);
		if (entered_state >= 0) {
		if (entered_state > 0) {
		local_irq_enable();
		goto exit_idle;
		}