kms/connector: Add getter for preferred mode

This replaces a helper used in tests. The intention is to use it from
other tests, and seemed like a good fit to place it under the KMS
connector object itself.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2159>

src/backends/native/meta-kms-connector.c

@@ -123,6 +123,26 @@ meta_kms_connector_can_clone (MetaKmsConnector *connector,
   return TRUE;
 }
 
+MetaKmsMode *
+meta_kms_connector_get_preferred_mode (MetaKmsConnector *connector)
+{
+  const MetaKmsConnectorState *state;
+  GList *l;
+
+  state = meta_kms_connector_get_current_state (connector);
+  for (l = state->modes; l; l = l->next)
+    {
+      MetaKmsMode *mode = l->data;
+      const drmModeModeInfo *drm_mode;
+
+      drm_mode = meta_kms_mode_get_drm_mode (mode);
+      if (drm_mode->type & DRM_MODE_TYPE_PREFERRED)
+        return mode;
+    }
+
+  return NULL;
+}
+
 const MetaKmsConnectorState *
 meta_kms_connector_get_current_state (MetaKmsConnector *connector)
 {

src/backends/native/meta-kms-connector.h

@@ -73,6 +73,9 @@ const char * meta_kms_connector_get_name (MetaKmsConnector *connector);
 gboolean meta_kms_connector_can_clone (MetaKmsConnector *connector,
                                        MetaKmsConnector *other_connector);
 
+META_EXPORT_TEST
+MetaKmsMode * meta_kms_connector_get_preferred_mode (MetaKmsConnector *connector);
+
 META_EXPORT_TEST
 const MetaKmsConnectorState * meta_kms_connector_get_current_state (MetaKmsConnector *connector);
 

src/tests/native-kms-device.c

@@ -58,6 +58,7 @@ meta_test_kms_device_sanity (void)
   g_assert_cmpuint (g_list_length (connectors), ==, 1);
   connector = META_KMS_CONNECTOR (connectors->data);
   g_assert (meta_kms_connector_get_device (connector) == device);
+  g_assert_nonnull (meta_kms_connector_get_preferred_mode (connector));
 
   crtcs = meta_kms_device_get_crtcs (device);
   g_assert_cmpuint (g_list_length (crtcs), ==, 1);

src/tests/native-kms-updates.c

@@ -54,26 +54,6 @@ meta_test_kms_update_sanity (void)
   meta_kms_update_free (update);
 }
 
-static MetaKmsMode *
-get_preferred_mode (MetaKmsConnector *connector)
-{
-  const MetaKmsConnectorState *state;
-  GList *l;
-
-  state = meta_kms_connector_get_current_state (connector);
-  for (l = state->modes; l; l = l->next)
-    {
-      MetaKmsMode *mode = l->data;
-      const drmModeModeInfo *drm_mode;
-
-      drm_mode = meta_kms_mode_get_drm_mode (mode);
-      if (drm_mode->type & DRM_MODE_TYPE_PREFERRED)
-        return mode;
-    }
-
-  g_assert_not_reached ();
-}
-
 static void
 meta_test_kms_update_plane_assignments (void)
 {
@@ -102,7 +82,7 @@ meta_test_kms_update_plane_assignments (void)
   cursor_plane = meta_kms_device_get_cursor_plane_for (device, crtc);
   g_assert_nonnull (cursor_plane);
 
-  mode = get_preferred_mode (connector);
+  mode = meta_kms_connector_get_preferred_mode (connector);
 
   mode_width = meta_kms_mode_get_width (mode);
   mode_height = meta_kms_mode_get_height (mode);
@@ -220,7 +200,7 @@ meta_test_kms_update_mode_sets (void)
   update = meta_kms_update_new (device);
   crtc = meta_get_test_kms_crtc (device);
   connector = meta_get_test_kms_connector (device);
-  mode = get_preferred_mode (connector);
+  mode = meta_kms_connector_get_preferred_mode (connector);
 
   meta_kms_update_mode_set (update, crtc,
                             g_list_append (NULL, connector),