drm/radeon: Properly handle DDC probe for DP bridges

commit 0a9069d34918659bc8a89e21e69e60b2b83291a3 upstream.

DDC information can be accessed using AUX CH

Fixes failure to probe monitors on some systems with
DP bridge chips.

agd5f: minor fixes

Signed-off-by: Niels Ole Salscheider <niels_ole@salscheider-online.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

4 files changed, 24 insertions, 11 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 87d494d9f7d1..6fd53b644dfc 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -689,7 +689,7 @@ radeon_vga_detect(struct drm_connector *connector, bool force)
 		ret = connector_status_disconnected;
 
 	if (radeon_connector->ddc_bus)
-		dret = radeon_ddc_probe(radeon_connector);
+		dret = radeon_ddc_probe(radeon_connector, false);
 	if (dret) {
 		radeon_connector->detected_by_load = false;
 		if (radeon_connector->edid) {
@@ -871,7 +871,7 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
 	bool dret = false;
 
 	if (radeon_connector->ddc_bus)
-		dret = radeon_ddc_probe(radeon_connector);
+		dret = radeon_ddc_probe(radeon_connector, false);
 	if (dret) {
 		radeon_connector->detected_by_load = false;
 		if (radeon_connector->edid) {
@@ -1299,7 +1299,8 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
 		if (encoder) {
 			/* setup ddc on the bridge */
 			radeon_atom_ext_encoder_setup_ddc(encoder);
-			if (radeon_ddc_probe(radeon_connector)) /* try DDC */
+			/* bridge chips are always aux */
+			if (radeon_ddc_probe(radeon_connector, true)) /* try DDC */
 				ret = connector_status_connected;
 			else if (radeon_connector->dac_load_detect) { /* try load detection */
 				struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
@@ -1317,7 +1318,8 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
 				if (radeon_dp_getdpcd(radeon_connector))
 					ret = connector_status_connected;
 			} else {
-				if (radeon_ddc_probe(radeon_connector))
+				/* try non-aux ddc (DP to DVI/HMDI/etc. adapter) */
+				if (radeon_ddc_probe(radeon_connector, false))
 					ret = connector_status_connected;
 			}
 		}
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index a22d6e6a49a2..aec8e0c04854 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -701,10 +701,15 @@ int radeon_ddc_get_modes(struct radeon_connector *radeon_connector)
 	if (radeon_connector->router.ddc_valid)
 		radeon_router_select_ddc_port(radeon_connector);
 
-	if ((radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_DisplayPort) ||
-	    (radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_eDP) ||
-	    (radeon_connector_encoder_get_dp_bridge_encoder_id(&radeon_connector->base) !=
-	     ENCODER_OBJECT_ID_NONE)) {
+	if (radeon_connector_encoder_get_dp_bridge_encoder_id(&radeon_connector->base) !=
+	    ENCODER_OBJECT_ID_NONE) {
+		struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
+
+		if (dig->dp_i2c_bus)
+			radeon_connector->edid = drm_get_edid(&radeon_connector->base,
+							      &dig->dp_i2c_bus->adapter);
+	} else if ((radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_DisplayPort) ||
+		   (radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_eDP)) {
 		struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
 
 		if ((dig->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT ||
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 1441b00ad687..cf203510b16b 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -34,7 +34,7 @@
  * radeon_ddc_probe
  *
  */
-bool radeon_ddc_probe(struct radeon_connector *radeon_connector)
+bool radeon_ddc_probe(struct radeon_connector *radeon_connector, bool use_aux)
 {
 	u8 out = 0x0;
 	u8 buf[8];
@@ -58,7 +58,13 @@ bool radeon_ddc_probe(struct radeon_connector *radeon_connector)
 	if (radeon_connector->router.ddc_valid)
 		radeon_router_select_ddc_port(radeon_connector);
 
-	ret = i2c_transfer(&radeon_connector->ddc_bus->adapter, msgs, 2);
+	if (use_aux) {
+		struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
+		ret = i2c_transfer(&dig->dp_i2c_bus->adapter, msgs, 2);
+	} else {
+		ret = i2c_transfer(&radeon_connector->ddc_bus->adapter, msgs, 2);
+	}
+
 	if (ret != 2)
 		/* Couldn't find an accessible DDC on this connector */
 		return false;
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index bbb372ecb6b4..bb42df4df1c8 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -523,7 +523,7 @@ extern void radeon_i2c_put_byte(struct radeon_i2c_chan *i2c,
 				u8 val);
 extern void radeon_router_select_ddc_port(struct radeon_connector *radeon_connector);
 extern void radeon_router_select_cd_port(struct radeon_connector *radeon_connector);
-extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector);
+extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector, bool use_aux);
 extern int radeon_ddc_get_modes(struct radeon_connector *radeon_connector);
 
 extern struct drm_encoder *radeon_best_encoder(struct drm_connector *connector);