drm/radeon/dpm: fix 120hz handling harder

commit 3899ca84 upstream.

Need to expand the check to handle short circuiting
if the selected state is the same as current state.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=87796Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/gpu/drm/radeon/radeon.h

@@ -1512,6 +1512,7 @@ struct radeon_dpm {
 	int			new_active_crtc_count;
 	u32			current_active_crtcs;
 	int			current_active_crtc_count;
+	bool single_display;
 	struct radeon_dpm_dynamic_state dyn_state;
 	struct radeon_dpm_fan fan;
 	u32 tdp_limit;

drivers/gpu/drm/radeon/radeon_pm.c

@@ -704,12 +704,8 @@ static void radeon_dpm_thermal_work_handler(struct work_struct *work)
 	radeon_pm_compute_clocks(rdev);
 }
 
-static struct radeon_ps *radeon_dpm_pick_power_state(struct radeon_device *rdev,
-						     enum radeon_pm_state_type dpm_state)
+static bool radeon_dpm_single_display(struct radeon_device *rdev)
 {
-	int i;
-	struct radeon_ps *ps;
-	u32 ui_class;
 	bool single_display = (rdev->pm.dpm.new_active_crtc_count < 2) ?
 		true : false;
 
@@ -719,6 +715,17 @@ static struct radeon_ps *radeon_dpm_pick_power_state(struct radeon_device *rdev,
 			single_display = false;
 	}
 
+	return single_display;
+}
+
+static struct radeon_ps *radeon_dpm_pick_power_state(struct radeon_device *rdev,
+						     enum radeon_pm_state_type dpm_state)
+{
+	int i;
+	struct radeon_ps *ps;
+	u32 ui_class;
+	bool single_display = radeon_dpm_single_display(rdev);
+
 	/* certain older asics have a separare 3D performance state,
 	 * so try that first if the user selected performance
 	 */
@@ -844,6 +851,7 @@ static void radeon_dpm_change_power_state_locked(struct radeon_device *rdev)
 	struct radeon_ps *ps;
 	enum radeon_pm_state_type dpm_state;
 	int ret;
+	bool single_display = radeon_dpm_single_display(rdev);
 
 	/* if dpm init failed */
 	if (!rdev->pm.dpm_enabled)
@@ -868,6 +876,9 @@ static void radeon_dpm_change_power_state_locked(struct radeon_device *rdev)
 		/* vce just modifies an existing state so force a change */
 		if (ps->vce_active != rdev->pm.dpm.vce_active)
 			goto force;
+		/* user has made a display change (such as timing) */
+		if (rdev->pm.dpm.single_display != single_display)
+			goto force;
 		if ((rdev->family < CHIP_BARTS) || (rdev->flags & RADEON_IS_IGP)) {
 			/* for pre-BTC and APUs if the num crtcs changed but state is the same,
 			 * all we need to do is update the display configuration.
@@ -930,6 +941,7 @@ static void radeon_dpm_change_power_state_locked(struct radeon_device *rdev)
 
 	rdev->pm.dpm.current_active_crtcs = rdev->pm.dpm.new_active_crtcs;
 	rdev->pm.dpm.current_active_crtc_count = rdev->pm.dpm.new_active_crtc_count;
+	rdev->pm.dpm.single_display = single_display;
 
 	/* wait for the rings to drain */
 	for (i = 0; i < RADEON_NUM_RINGS; i++) {