PM / suspend: Always use deepest C-state in the "freeze" sleep state

If freeze_enter() is called, we want to bypass the current cpuidle
governor and always use the deepest available (that is, not disabled)
C-state, because we want to save as much energy as reasonably possible
then and runtime latency constraints don't matter at that point, since
the system is in a sleep state anyway.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Aubrey Li <aubrey.li@linux.intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 8233cd4047d7..155721f7f909 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -54,9 +54,11 @@ static void freeze_begin(void)
 
 static void freeze_enter(void)
 {
+        cpuidle_use_deepest_state(true);
         cpuidle_resume();
         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
         cpuidle_pause();
+        cpuidle_use_deepest_state(false);
 }
 
 void freeze_wake(void)