diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index ed22a719440f..90b2d1644bd7 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -295,15 +295,15 @@ drm_atomic_get_connector_state(struct drm_atomic_state *state,
 	struct drm_mode_config *config = &connector->dev->mode_config;
 	struct drm_connector_state *connector_state;
 
+	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
+	if (ret)
+		return ERR_PTR(ret);
+
 	index = drm_connector_index(connector);
 
 	if (state->connector_states[index])
 		return state->connector_states[index];
 
-	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
-	if (ret)
-		return ERR_PTR(ret);
-
 	connector_state = connector->funcs->atomic_duplicate_state(connector);
 	if (!connector_state)
 		return ERR_PTR(-ENOMEM);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 56737e74b59d..5c878f172365 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -867,6 +867,8 @@ int drm_connector_init(struct drm_device *dev,
 
 	drm_connector_get_cmdline_mode(connector);
 
+	/* We should add connectors at the end to avoid upsetting the connector
+	 * index too much. */
 	list_add_tail(&connector->head, &dev->mode_config.connector_list);
 	dev->mode_config.num_connector++;
 
@@ -930,6 +932,9 @@ unsigned int drm_connector_index(struct drm_connector *connector)
 {
 	unsigned int index = 0;
 	struct drm_connector *tmp;
+	struct drm_mode_config *config = &connector->dev->mode_config;
+
+	WARN_ON(!drm_modeset_is_locked(&config->connection_mutex));
 
 	list_for_each_entry(tmp, &connector->dev->mode_config.connector_list, head) {
 		if (tmp == connector)