drm/radeon/kms: properly power up/down the eDP panel as needed (v4)

The eDP panel must be powered up for aux transactions, so power it
up for detect and mode probe functions, otherwise power it up or
down based on dpms.

v2:
- only mess with eDP panel on DCE4+
- only mess with eDP panel on eDP connectors, not all DP connectors
v3:
- be extra careful to only mess with eDP panels on eDP connectors
v4:
- avoid possible null derefernce if a connector has not been
assigned to the encoder

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -1008,9 +1008,21 @@ static void radeon_dp_connector_destroy(struct drm_connector *connector)
 static int radeon_dp_get_modes(struct drm_connector *connector)
 {
 	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+	struct radeon_connector_atom_dig *radeon_dig_connector = radeon_connector->con_priv;
 	int ret;
 
+	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
+		if (!radeon_dig_connector->edp_on)
+			atombios_set_edp_panel_power(connector,
+						     ATOM_TRANSMITTER_ACTION_POWER_ON);
+	}
 	ret = radeon_ddc_get_modes(radeon_connector);
+	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
+		if (!radeon_dig_connector->edp_on)
+			atombios_set_edp_panel_power(connector,
+						     ATOM_TRANSMITTER_ACTION_POWER_OFF);
+	}
+
 	return ret;
 }
 
@@ -1029,8 +1041,14 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
 	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
 		/* eDP is always DP */
 		radeon_dig_connector->dp_sink_type = CONNECTOR_OBJECT_ID_DISPLAYPORT;
+		if (!radeon_dig_connector->edp_on)
+			atombios_set_edp_panel_power(connector,
+						     ATOM_TRANSMITTER_ACTION_POWER_ON);
 		if (radeon_dp_getdpcd(radeon_connector))
 			ret = connector_status_connected;
+		if (!radeon_dig_connector->edp_on)
+			atombios_set_edp_panel_power(connector,
+						     ATOM_TRANSMITTER_ACTION_POWER_OFF);
 	} else {
 		radeon_dig_connector->dp_sink_type = radeon_dp_getsinktype(radeon_connector);
 		if (radeon_dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT) {

drivers/gpu/drm/radeon/radeon_encoders.c

@@ -990,6 +990,36 @@ atombios_dig_transmitter_setup(struct drm_encoder *encoder, int action, uint8_t
 	atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
 }
 
+void
+atombios_set_edp_panel_power(struct drm_connector *connector, int action)
+{
+	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+	struct drm_device *dev = radeon_connector->base.dev;
+	struct radeon_device *rdev = dev->dev_private;
+	union dig_transmitter_control args;
+	int index = GetIndexIntoMasterTable(COMMAND, UNIPHYTransmitterControl);
+	uint8_t frev, crev;
+
+	if (connector->connector_type != DRM_MODE_CONNECTOR_eDP)
+		return;
+
+	if (!ASIC_IS_DCE4(rdev))
+		return;
+
+	if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) ||
+	    (action != ATOM_TRANSMITTER_ACTION_POWER_OFF))
+		return;
+
+	if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev, &crev))
+		return;
+
+	memset(&args, 0, sizeof(args));
+
+	args.v1.ucAction = action;
+
+	atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+}
+
 static void
 atombios_yuv_setup(struct drm_encoder *encoder, bool enable)
 {
@@ -1094,6 +1124,15 @@ radeon_atom_encoder_dpms(struct drm_encoder *encoder, int mode)
 			if (atombios_get_encoder_mode(encoder) == ATOM_ENCODER_MODE_DP) {
 				struct drm_connector *connector = radeon_get_connector_for_encoder(encoder);
 
+				if (connector &&
+				    (connector->connector_type == DRM_MODE_CONNECTOR_eDP)) {
+					struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+					struct radeon_connector_atom_dig *radeon_dig_connector =
+						radeon_connector->con_priv;
+					atombios_set_edp_panel_power(connector,
+								     ATOM_TRANSMITTER_ACTION_POWER_ON);
+					radeon_dig_connector->edp_on = true;
+				}
 				dp_link_train(encoder, connector);
 				if (ASIC_IS_DCE4(rdev))
 					atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_ON);
@@ -1106,8 +1145,19 @@ radeon_atom_encoder_dpms(struct drm_encoder *encoder, int mode)
 		case DRM_MODE_DPMS_OFF:
 			atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_DISABLE_OUTPUT, 0, 0);
 			if (atombios_get_encoder_mode(encoder) == ATOM_ENCODER_MODE_DP) {
+				struct drm_connector *connector = radeon_get_connector_for_encoder(encoder);
+
 				if (ASIC_IS_DCE4(rdev))
 					atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_OFF);
+				if (connector &&
+				    (connector->connector_type == DRM_MODE_CONNECTOR_eDP)) {
+					struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+					struct radeon_connector_atom_dig *radeon_dig_connector =
+						radeon_connector->con_priv;
+					atombios_set_edp_panel_power(connector,
+								     ATOM_TRANSMITTER_ACTION_POWER_OFF);
+					radeon_dig_connector->edp_on = false;
+				}
 			}
 			if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT))
 				atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_LCD_BLOFF, 0, 0);

drivers/gpu/drm/radeon/radeon_mode.h

@@ -385,6 +385,7 @@ struct radeon_connector_atom_dig {
 	u8 dp_sink_type;
 	int dp_clock;
 	int dp_lane_count;
+	bool edp_on;
 };
 
 struct radeon_gpio_rec {
@@ -526,6 +527,7 @@ struct drm_encoder *radeon_encoder_legacy_tmds_ext_add(struct drm_device *dev, i
 extern void atombios_external_tmds_setup(struct drm_encoder *encoder, int action);
 extern void atombios_digital_setup(struct drm_encoder *encoder, int action);
 extern int atombios_get_encoder_mode(struct drm_encoder *encoder);
+extern void atombios_set_edp_panel_power(struct drm_connector *connector, int action);
 extern void radeon_encoder_set_active_device(struct drm_encoder *encoder);
 
 extern void radeon_crtc_load_lut(struct drm_crtc *crtc);