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

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Commit 51164251f5 "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: 51164251f5 "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>
This commit is contained in:
Sudeep Holla 2016-01-21 11:19:29 +00:00 committed by Rafael J. Wysocki
parent 5bb1729cbd
commit 6f16886b7c
2 changed files with 2 additions and 2 deletions
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2
drivers/cpuidle/cpuidle.c
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@ -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;

2
kernel/sched/idle.c
View file

@ -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;
}