drm/radeon/pm: autoswitch power state when in balanced mode

The current default of always using the performance power state leads
to increased power consumption of mobile devices, which have a dedicated
battery power state. Switch between the performance and battery power
state automatically, dpending on the current AC power status, when the
user asked for the balanced power state.

The user can still override this logic by asking for the performance
or battery power state explicitly.
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_pm.c

@@ -47,6 +47,7 @@ static bool radeon_pm_in_vbl(struct radeon_device *rdev);
 static bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish);
 static void radeon_pm_update_profile(struct radeon_device *rdev);
 static void radeon_pm_set_clocks(struct radeon_device *rdev);
+static void radeon_pm_compute_clocks_dpm(struct radeon_device *rdev);
 
 int radeon_pm_get_type_index(struct radeon_device *rdev,
 			     enum radeon_pm_state_type ps_type,
@@ -79,6 +80,8 @@ void radeon_pm_acpi_event_handler(struct radeon_device *rdev)
 				radeon_dpm_enable_bapm(rdev, rdev->pm.dpm.ac_power);
 		}
 		mutex_unlock(&rdev->pm.mutex);
+		/* allow new DPM state to be picked */
+		radeon_pm_compute_clocks_dpm(rdev);
 	} else if (rdev->pm.pm_method == PM_METHOD_PROFILE) {
 		if (rdev->pm.profile == PM_PROFILE_AUTO) {
 			mutex_lock(&rdev->pm.mutex);
@@ -882,7 +885,8 @@ static struct radeon_ps *radeon_dpm_pick_power_state(struct radeon_device *rdev,
 		dpm_state = POWER_STATE_TYPE_INTERNAL_3DPERF;
 	/* balanced states don't exist at the moment */
 	if (dpm_state == POWER_STATE_TYPE_BALANCED)
-		dpm_state = POWER_STATE_TYPE_PERFORMANCE;
+		dpm_state = rdev->pm.dpm.ac_power ?
+			POWER_STATE_TYPE_PERFORMANCE : POWER_STATE_TYPE_BATTERY;
 
 restart_search:
 	/* Pick the best power state based on current conditions */