backend/drm: add support for wlr_swapchain buffer age

backend/drm/drm.c

@@ -331,16 +331,25 @@ static bool drm_connector_attach_render(struct wlr_output *output,
 	return drm_surface_make_current(&conn->crtc->primary->surf, buffer_age);
 }
 
+static void drm_plane_set_committed(struct wlr_drm_plane *plane) {
+	drm_fb_move(&plane->queued_fb, &plane->pending_fb);
+
+	struct wlr_buffer *queued = plane->queued_fb.wlr_buf;
+	if (queued != NULL) {
+		wlr_swapchain_set_buffer_submitted(plane->surf.swapchain, queued);
+	}
+}
+
 static bool drm_crtc_commit(struct wlr_drm_connector *conn, uint32_t flags) {
 	struct wlr_drm_backend *drm =
 		get_drm_backend_from_backend(conn->output.backend);
 	struct wlr_drm_crtc *crtc = conn->crtc;
 	bool ok = drm->iface->crtc_commit(drm, conn, flags);
 	if (ok && !(flags & DRM_MODE_ATOMIC_TEST_ONLY)) {
 		memcpy(&crtc->current, &crtc->pending, sizeof(struct wlr_drm_crtc_state));
-		drm_fb_move(&crtc->primary->queued_fb, &crtc->primary->pending_fb);
+		drm_plane_set_committed(crtc->primary);
 		if (crtc->cursor != NULL) {
-			drm_fb_move(&crtc->cursor->queued_fb, &crtc->cursor->pending_fb);
+			drm_plane_set_committed(crtc->cursor);
 		}
 	} else {
 		memcpy(&crtc->pending, &crtc->current, sizeof(struct wlr_drm_crtc_state));

backend/drm/renderer.c

@@ -136,7 +136,7 @@ static void finish_drm_surface(struct wlr_drm_surface *surf) {
 bool drm_surface_make_current(struct wlr_drm_surface *surf,
 		int *buffer_age) {
 	assert(surf->back_buffer == NULL);
-	surf->back_buffer = wlr_swapchain_acquire(surf->swapchain);
+	surf->back_buffer = wlr_swapchain_acquire(surf->swapchain, buffer_age);
 	if (surf->back_buffer == NULL) {
 		wlr_log(WLR_ERROR, "Failed to acquire swapchain buffer");
 		return false;
@@ -150,10 +150,6 @@ bool drm_surface_make_current(struct wlr_drm_surface *surf,
 		return false;
 	}
 
-	// TODO: damage tracking
-	if (buffer_age != NULL) {
-		*buffer_age = -1;
-	}
 	return true;
 }