Hdmi: Add check edid function to avoid drm panic

Change-Id: Id53fea6076d5e7425e0a18cf824b2f0bce61c757

Author: gary_gen

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -2750,6 +2750,24 @@ static void dw_hdmi_connector_force(struct drm_connector *connector)
 	mutex_unlock(&hdmi->mutex);
 }
 
+static bool dw_hdmi_connector_check_edid(struct drm_connector *connector)
+{
+	struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi,
+					     connector);
+	struct edid *edid;
+
+	if (!hdmi->ddc)
+	    return false;
+
+	edid = drm_get_edid(connector, hdmi->ddc);
+	if (edid) {
+	    kfree(edid);
+	    return true;
+	} else {
+	    return false;
+	}
+}
+
 static const struct drm_connector_funcs dw_hdmi_connector_funcs = {
 	.dpms = drm_helper_connector_dpms,
 	.fill_modes = drm_helper_probe_single_connector_modes,
@@ -2778,6 +2796,7 @@ static const struct drm_connector_helper_funcs dw_hdmi_connector_helper_funcs =
 	.best_encoder = dw_hdmi_connector_best_encoder,
 	.atomic_begin = dw_hdmi_connector_atomic_begin,
 	.atomic_flush = dw_hdmi_connector_atomic_flush,
+	.check_edid = dw_hdmi_connector_check_edid,
 };
 
 static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = {

drivers/gpu/drm/drm_probe_helper.c

@@ -265,10 +265,12 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
 			connector->name);
 
 	if (!strcmp(connector->name, "HDMI-A-1")) {
-		edid_manufacturer = (struct edid *) connector->edid_blob_ptr->data;
-		drm_iex_monitor = drm_dect_iex_edid(edid_manufacturer);
-		drm_acer_kg221q_monitor = drm_dect_acer_kg221q_edid(edid_manufacturer);
-		drm_asus_vz229h_monitor = drm_dect_asus_vz229h_edid(edid_manufacturer);
+		if( (*connector_funcs->check_edid)(connector) ) {
+			edid_manufacturer = (struct edid *) connector->edid_blob_ptr->data;
+			drm_iex_monitor = drm_dect_iex_edid(edid_manufacturer);
+			drm_acer_kg221q_monitor = drm_dect_acer_kg221q_edid(edid_manufacturer);
+			drm_asus_vz229h_monitor = drm_dect_asus_vz229h_edid(edid_manufacturer);
+		}
 	}
 	list_for_each_entry(mode, &connector->modes, head) {
 		drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);

include/drm/drm_crtc_helper.h

@@ -189,6 +189,7 @@ struct drm_connector_helper_funcs {
 			     struct drm_connector_state *conn_state);
 	void (*atomic_flush)(struct drm_connector *connector,
 			     struct drm_connector_state *conn_state);
+	bool (*check_edid)(struct drm_connector *connector);
 };
 
 extern void drm_helper_disable_unused_functions(struct drm_device *dev);