[PATCH 4.15 026/146] drm/amd/powerplay/smu7: allow mclk switching with no displays

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Deucher <alexander.deucher@xxxxxxx>

commit 51954e17914aaadf18d97b21c2a2cee16fa29513 upstream.

If there are no displays attached, there is no reason to disable
mclk switching.

Fixes mclks getting set to high when there are no displays attached.

Reviewed-by: Eric Huang <JinhuiEric.Huang@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
@@ -2791,10 +2791,13 @@ static int smu7_apply_state_adjust_rules
 				    PHM_PlatformCaps_DisableMclkSwitchingForFrameLock);
 
 
-	disable_mclk_switching = ((1 < info.display_count) ||
-				  disable_mclk_switching_for_frame_lock ||
-				  smu7_vblank_too_short(hwmgr, mode_info.vblank_time_us) ||
-				  (mode_info.refresh_rate > 120));
+	if (info.display_count == 0)
+		disable_mclk_switching = false;
+	else
+		disable_mclk_switching = ((1 < info.display_count) ||
+					  disable_mclk_switching_for_frame_lock ||
+					  smu7_vblank_too_short(hwmgr, mode_info.vblank_time_us) ||
+					  (mode_info.refresh_rate > 120));
 
 	sclk = smu7_ps->performance_levels[0].engine_clock;
 	mclk = smu7_ps->performance_levels[0].memory_clock;