drm/radeon: fix multi-head power profile stability on BTC+ asics

vddci needs to track mclk for multi-head.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/radeon/evergreen.c

@@ -403,6 +403,19 @@ void evergreen_pm_misc(struct radeon_device *rdev)
 			rdev->pm.current_vddc = voltage->voltage;
 			DRM_DEBUG("Setting: vddc: %d\n", voltage->voltage);
 		}
+
+		/* starting with BTC, there is one state that is used for both
+		 * MH and SH.  Difference is that we always use the high clock index for
+		 * mclk and vddci.
+		 */
+		if ((rdev->pm.pm_method == PM_METHOD_PROFILE) &&
+		    (rdev->family >= CHIP_BARTS) &&
+		    rdev->pm.active_crtc_count &&
+		    ((rdev->pm.profile_index == PM_PROFILE_MID_MH_IDX) ||
+		     (rdev->pm.profile_index == PM_PROFILE_LOW_MH_IDX)))
+			voltage = &rdev->pm.power_state[req_ps_idx].
+				clock_info[rdev->pm.profiles[PM_PROFILE_HIGH_MH_IDX].dpms_on_cm_idx].voltage;
+
 		/* 0xff01 is a flag rather then an actual voltage */
 		if (voltage->vddci == 0xff01)
 			return;

drivers/gpu/drm/radeon/radeon_pm.c

@@ -169,7 +169,7 @@ static void radeon_set_power_state(struct radeon_device *rdev)
 
 		/* starting with BTC, there is one state that is used for both
 		 * MH and SH.  Difference is that we always use the high clock index for
-		 * mclk.
+		 * mclk and vddci.
 		 */
 		if ((rdev->pm.pm_method == PM_METHOD_PROFILE) &&
 		    (rdev->family >= CHIP_BARTS) &&