drm/amd/display: Fix eDP panel light-up

 Power-down panel on disale only if sink exists
 otherwise it fails edid read during init sequence

Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
index aac2420..5bdcd50 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
@@ -114,7 +114,9 @@ void dp_disable_link_phy(struct dc_link *link, enum signal_type signal)
 
        if (signal == SIGNAL_TYPE_EDP) {
                link->link_enc->funcs->backlight_control(link->link_enc, false);
-               link->link_enc->funcs->power_control(link->link_enc, false);
+               if (link->dpcd_sink_count)
+                       link->link_enc->funcs->power_control(link->link_enc,
+                                                                       false);
        }
 
        link->link_enc->funcs->disable_output(link->link_enc, signal);