render: add explicit sync API

include/wlr/render/pass.h

@@ -33,6 +33,17 @@ struct wlr_buffer_pass_options {
 	/* Color transform to apply to the output of the render pass,
 	 * leave NULL to indicate sRGB/no custom transform */
 	struct wlr_color_transform *color_transform;
+
+	/* Signal a timeline synchronization point when the render pass completes.
+	 *
+	 * When a compositor provides a signal timeline, the renderer may skip
+	 * implicit signal synchronization.
+	 *
+	 * Support for this feature is advertised by features.timeline in
+	 * struct wlr_renderer.
+	 */
+	struct wlr_drm_syncobj_timeline *signal_timeline;
+	uint64_t signal_point;
 };
 
 /**
@@ -88,6 +99,17 @@ struct wlr_render_texture_options {
 	enum wlr_scale_filter_mode filter_mode;
 	/* Blend mode */
 	enum wlr_render_blend_mode blend_mode;
+
+	/* Wait for a timeline synchronization point before texturing.
+	 *
+	 * When a compositor provides a wait timeline, the renderer may skip
+	 * implicit wait synchronization.
+	 *
+	 * Support for this feature is advertised by features.timeline in
+	 * struct wlr_renderer.
+	 */
+	struct wlr_drm_syncobj_timeline *wait_timeline;
+	uint64_t wait_point;
 };
 
 /**

include/wlr/render/wlr_renderer.h

@@ -45,6 +45,12 @@ struct wlr_renderer {
 		 * Does the renderer support color transforms on its output?
 		 */
 		bool output_color_transform;
+		/**
+		 * Whether wait/signal timelines are supported.
+		 *
+		 * See struct wlr_drm_syncobj_timeline.
+		 */
+		bool timeline;
 	} features;
 
 	// private state