[PATCH v4 7/7] drm/bridge_connector: hook drm_atomic_helper_connector_hdmi_update_edid()

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

Extend drm_bridge_connector code to read the EDID and use it to update
connector status if the bridge chain implements HDMI bridge. Performing
it from the generic location minimizes individual bridge's code and
enforces standard behaviour from all corresponding drivers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 67 ++++++++++++++++++++------
 1 file changed, 53 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 12ab9f14cc8a8672478ae2804c9a68d766d88ea5..71ae3b2c9049016d1cc0d39a787f6461633efd53 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -17,6 +17,7 @@
 #include <drm/drm_edid.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/display/drm_hdmi_state_helper.h>
 
@@ -175,17 +176,55 @@ static void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
  * Bridge Connector Functions
  */
 
+static const struct drm_edid *
+drm_bridge_connector_read_edid(struct drm_connector *connector,
+			       enum drm_connector_status status)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	const struct drm_edid *drm_edid;
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_edid;
+	if (!bridge)
+		return NULL;
+
+	if (status != connector_status_connected)
+		return NULL;
+
+	drm_edid = drm_bridge_edid_read(bridge, connector);
+	if (!drm_edid_valid(drm_edid)) {
+		drm_edid_free(drm_edid);
+		return NULL;
+	}
+
+	return drm_edid;
+}
+
 static enum drm_connector_status
 drm_bridge_connector_detect(struct drm_connector *connector, bool force)
 {
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
 	struct drm_bridge *detect = bridge_connector->bridge_detect;
+	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
 	enum drm_connector_status status;
 
 	if (detect) {
 		status = detect->funcs->detect(detect);
 
+		if (hdmi) {
+			const struct drm_edid *drm_edid;
+			int ret;
+
+			drm_edid = drm_bridge_connector_read_edid(connector, status);
+			ret = drm_atomic_helper_connector_hdmi_update_edid(connector, drm_edid);
+			if (ret)
+				drm_warn(connector->dev, "updating EDID failed with %d\n", ret);
+
+			drm_edid_free(drm_edid);
+		}
+
 		drm_bridge_connector_hpd_notify(connector, status);
 	} else {
 		switch (connector->connector_type) {
@@ -246,29 +285,29 @@ static const struct drm_connector_funcs drm_bridge_connector_funcs = {
 static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector,
 					       struct drm_bridge *bridge)
 {
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
 	enum drm_connector_status status;
 	const struct drm_edid *drm_edid;
-	int n;
 
 	status = drm_bridge_connector_detect(connector, false);
 	if (status != connector_status_connected)
-		goto no_edid;
+		return 0;
 
-	drm_edid = drm_bridge_edid_read(bridge, connector);
-	if (!drm_edid_valid(drm_edid)) {
+	/* In HDMI setup the EDID has been read and handled as a part of .detect() */
+	if (!hdmi) {
+		drm_edid = drm_bridge_connector_read_edid(connector, status);
+		if (!drm_edid) {
+			drm_edid_connector_update(connector, NULL);
+			return 0;
+		}
+
+		drm_edid_connector_update(connector, drm_edid);
 		drm_edid_free(drm_edid);
-		goto no_edid;
 	}
 
-	drm_edid_connector_update(connector, drm_edid);
-	n = drm_edid_connector_add_modes(connector);
-
-	drm_edid_free(drm_edid);
-	return n;
-
-no_edid:
-	drm_edid_connector_update(connector, NULL);
-	return 0;
+	return drm_edid_connector_add_modes(connector);
 }
 
 static int drm_bridge_connector_get_modes(struct drm_connector *connector)

-- 
2.39.5