From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
If the :enter_dead() idle state callback fails for a certain state,
there may be still a shallower state for which it will work.
Because the only caller of cpuidle_play_dead(), native_play_dead(),
falls back to hlt_play_dead() if it returns an error, it should
better try all of the idle states for which :enter_dead() is present
before failing, so change it accordingly.
Also notice that the :enter_dead() state callback is not expected
to return on success (the CPU should be "dead" then), so make
cpuidle_play_dead() ignore its return value.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Tested-by: Mario Limonciello <mario.limonciello@xxxxxxx> # 6.12-rc7
---
v1 -> v2:
* Make cpuidle_play_dead() never return 0.
* Add tags from Mario (I have added them because the change of the patch
should not make a practical difference, but if you want them to be
dropped, please let me know).
---
drivers/cpuidle/cpuidle.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
Index: linux-pm/drivers/cpuidle/cpuidle.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/cpuidle.c
+++ linux-pm/drivers/cpuidle/cpuidle.c
@@ -69,11 +69,15 @@ int cpuidle_play_dead(void)
if (!drv)
return -ENODEV;
- /* Find lowest-power state that supports long-term idle */
- for (i = drv->state_count - 1; i >= 0; i--)
+ for (i = drv->state_count - 1; i >= 0; i--) {
if (drv->states[i].enter_dead)
- return drv->states[i].enter_dead(dev, i);
+ drv->states[i].enter_dead(dev, i);
+ }
+ /*
+ * If :enter_dead() is successful, it will never return, so reaching
+ * here means that all of them failed above or were not present.
+ */
return -ENODEV;
}
