drm/radeon/kms: properly set panel mode for eDP

This should make eDP more reliable.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_dp.c

@@ -553,6 +553,7 @@ static void radeon_dp_set_panel_mode(struct drm_encoder *encoder,
 {
 	struct drm_device *dev = encoder->dev;
 	struct radeon_device *rdev = dev->dev_private;
+	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
 	int panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE;
 
 	if (!ASIC_IS_DCE4(rdev))
@@ -560,10 +561,20 @@ static void radeon_dp_set_panel_mode(struct drm_encoder *encoder,
 
 	if (radeon_connector_encoder_is_dp_bridge(connector))
 		panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE;
+	else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
+		u8 tmp = radeon_read_dpcd_reg(radeon_connector, DP_EDP_CONFIGURATION_CAP);
+		if (tmp & 1)
+			panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
+	}
 
 	atombios_dig_encoder_setup(encoder,
 				   ATOM_ENCODER_CMD_SETUP_PANEL_MODE,
 				   panel_mode);
+
+	if ((connector->connector_type == DRM_MODE_CONNECTOR_eDP) &&
+	    (panel_mode == DP_PANEL_MODE_INTERNAL_DP2_MODE)) {
+		radeon_write_dpcd_reg(radeon_connector, DP_EDP_CONFIGURATION_SET, 1);
+	}
 }
 
 void radeon_dp_set_link_config(struct drm_connector *connector,

include/drm/drm_dp_helper.h

@@ -72,6 +72,7 @@
 
 #define DP_MAIN_LINK_CHANNEL_CODING         0x006
 
+#define DP_EDP_CONFIGURATION_CAP            0x00d
 #define DP_TRAINING_AUX_RD_INTERVAL         0x00e
 
 #define DP_PSR_SUPPORT                      0x070
@@ -159,6 +160,8 @@
 # define DP_CP_IRQ			    (1 << 2)
 # define DP_SINK_SPECIFIC_IRQ		    (1 << 6)
 
+#define DP_EDP_CONFIGURATION_SET            0x10a
+
 #define DP_LANE0_1_STATUS		    0x202
 #define DP_LANE2_3_STATUS		    0x203
 # define DP_LANE_CR_DONE		    (1 << 0)