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/include/linux/cpuidle.h b/include/linux/cpuidle.h
index a8d5bd391a26..c51a436135c4 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -143,6 +143,7 @@ extern void cpuidle_resume(void);
 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 extern int cpuidle_play_dead(void);
+extern void cpuidle_use_deepest_state(bool enable);
 
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 #else
@@ -175,6 +176,7 @@ static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 {return -ENODEV; }
 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 static inline int cpuidle_play_dead(void) {return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable) {}
 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
         struct cpuidle_device *dev) {return NULL; }
 #endif