libweston/backends: Move damage flush into backends

Currently we flush damage for the "primary plane" every repaint, but this
is folly.

The drm backend may skip rendering entirely if using an all-planes
composition. This could leave the renderer plane in a messy state if a
surface on an overlay plane disappears.

Instead, let the backends flush the primary plane damage when they know
they need to render.

Fixes #864

Signed-off-by: Derek Foreman <derek.foreman@collabora.com>

include/libweston/libweston.h

@@ -548,7 +548,7 @@ struct weston_output {
 	struct weston_log_pacer pixman_overdraw_pacer;
 
 	int (*start_repaint_loop)(struct weston_output *output);
-	int (*repaint)(struct weston_output *output, pixman_region32_t *damage);
+	int (*repaint)(struct weston_output *output);
 	void (*destroy)(struct weston_output *output);
 	void (*assign_planes)(struct weston_output *output);
 	int (*switch_mode)(struct weston_output *output, struct weston_mode *mode);

libweston/backend-drm/drm-internal.h

@@ -965,7 +965,7 @@ bool
 drm_plane_is_available(struct drm_plane *plane, struct drm_output *output);
 
 void
-drm_output_render(struct drm_output_state *state, pixman_region32_t *damage);
+drm_output_render(struct drm_output_state *state);
 
 int
 parse_gbm_format(const char *s, const struct pixel_format_info *default_format,

libweston/backend-drm/drm-virtual.c

@@ -202,8 +202,7 @@ drm_virtual_output_submit_frame(struct drm_output *output,
 }
 
 static int
-drm_virtual_output_repaint(struct weston_output *output_base,
-			   pixman_region32_t *damage)
+drm_virtual_output_repaint(struct weston_output *output_base)
 {
 	struct drm_output_state *state = NULL;
 	struct drm_output *output = to_drm_output(output_base);
@@ -237,7 +236,7 @@ drm_virtual_output_repaint(struct weston_output *output_base,
 						   pending_state,
 						   DRM_OUTPUT_STATE_CLEAR_PLANES);
 
-	drm_output_render(state, damage);
+	drm_output_render(state);
 	scanout_state = drm_output_state_get_plane(state, scanout_plane);
 	if (!scanout_state || !scanout_state->fb)
 		goto err;

libweston/backend-drm/drm.c

@@ -355,7 +355,7 @@ drm_output_render_pixman(struct drm_output_state *state,
 }
 
 void
-drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
+drm_output_render(struct drm_output_state *state)
 {
 	struct drm_output *output = state->output;
 	struct drm_device *device = output->device;
@@ -365,7 +365,7 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 	struct drm_property_info *damage_info =
 		&scanout_plane->props[WDRM_PLANE_FB_DAMAGE_CLIPS];
 	struct drm_fb *fb;
-	pixman_region32_t scanout_damage;
+	pixman_region32_t damage, scanout_damage;
 	pixman_box32_t *rects;
 	int n_rects;
 
@@ -375,6 +375,10 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 	if (scanout_state->fb)
 		return;
 
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(&output->base, &damage);
+
 	/*
 	 * If we don't have any damage on the primary plane, and we already
 	 * have a renderer buffer active, we can reuse it; else we pass
@@ -382,7 +386,7 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 	 * area. But, we still have to call the renderer anyway if any screen
 	 * capture is pending, otherwise the capture will not complete.
 	 */
-	if (!pixman_region32_not_empty(damage) &&
+	if (!pixman_region32_not_empty(&damage) &&
 	    wl_list_empty(&output->base.frame_signal.listener_list) &&
 	    !weston_output_has_renderer_capture_tasks(&output->base) &&
 	    scanout_plane->state_cur->fb &&
@@ -390,14 +394,14 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 	     scanout_plane->state_cur->fb->type == BUFFER_PIXMAN_DUMB)) {
 		fb = drm_fb_ref(scanout_plane->state_cur->fb);
 	} else if (c->renderer->type == WESTON_RENDERER_PIXMAN) {
-		fb = drm_output_render_pixman(state, damage);
+		fb = drm_output_render_pixman(state, &damage);
 	} else {
-		fb = drm_output_render_gl(state, damage);
+		fb = drm_output_render_gl(state, &damage);
 	}
 
 	if (!fb) {
 		drm_plane_state_put_back(scanout_state);
-		return;
+		goto out;
 	}
 
 	scanout_state->fb = fb;
@@ -417,13 +421,13 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 
 	/* Don't bother calculating plane damage if the plane doesn't support it */
 	if (damage_info->prop_id == 0)
-		return;
+		goto out;
 
 	pixman_region32_init(&scanout_damage);
 
 	weston_region_global_to_output(&scanout_damage,
 				       &output->base,
-				       damage);
+				       &damage);
 
 	assert(scanout_state->damage_blob_id == 0);
 
@@ -440,6 +444,8 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 				  &scanout_state->damage_blob_id);
 
 	pixman_region32_fini(&scanout_damage);
+out:
+	pixman_region32_fini(&damage);
 }
 
 static uint32_t
@@ -651,7 +657,7 @@ cursor_bo_update(struct drm_output *output, struct weston_view *ev)
 #endif
 
 static int
-drm_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
+drm_output_repaint(struct weston_output *output_base)
 {
 	struct drm_output *output = to_drm_output(output_base);
 	struct drm_output_state *state = NULL;
@@ -718,7 +724,7 @@ drm_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
 	if (device->atomic_modeset)
 		drm_output_pick_writeback_capture_task(output);
 
-	drm_output_render(state, damage);
+	drm_output_render(state);
 	scanout_state = drm_output_state_get_plane(state,
 						   output->scanout_plane);
 	if (!scanout_state || !scanout_state->fb)

libweston/backend-headless/headless.c

@@ -152,11 +152,11 @@ headless_output_update_gl_border(struct headless_output *output)
 }
 
 static int
-headless_output_repaint(struct weston_output *output_base,
-		       pixman_region32_t *damage)
+headless_output_repaint(struct weston_output *output_base)
 {
 	struct headless_output *output = to_headless_output(output_base);
 	struct weston_compositor *ec;
+	pixman_region32_t damage;
 
 	assert(output);
 
@@ -164,9 +164,15 @@ headless_output_repaint(struct weston_output *output_base,
 
 	headless_output_update_gl_border(output);
 
-	ec->renderer->repaint_output(&output->base, damage,
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
+	ec->renderer->repaint_output(&output->base, &damage,
 				     output->renderbuffer);
 
+	pixman_region32_fini(&damage);
+
 	wl_event_source_timer_update(output->finish_frame_timer, 16);
 
 	return 0;

libweston/backend-pipewire/pipewire.c

@@ -725,19 +725,24 @@ pipewire_submit_buffer(struct pipewire_output *output,
 }
 
 static int
-pipewire_output_repaint(struct weston_output *base, pixman_region32_t *damage)
+pipewire_output_repaint(struct weston_output *base)
 {
 	struct pipewire_output *output = to_pipewire_output(base);
 	struct weston_compositor *ec = output->base.compositor;
 	struct pw_buffer *buffer;
 	struct pipewire_frame_data *frame_data;
+	pixman_region32_t damage;
 
 	assert(output);
 
 	if (pw_stream_get_state(output->stream, NULL) != PW_STREAM_STATE_STREAMING)
 		goto out;
 
-	if (!pixman_region32_not_empty(damage))
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(base, &damage);
+
+	if (!pixman_region32_not_empty(&damage))
 		goto out;
 
 	buffer = pw_stream_dequeue_buffer(output->stream);
@@ -748,12 +753,14 @@ pipewire_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 	pipewire_output_debug(output, "dequeued buffer: %p", buffer);
 
 	frame_data = buffer->user_data;
-	ec->renderer->repaint_output(&output->base, damage, frame_data->renderbuffer);
+	ec->renderer->repaint_output(&output->base, &damage, frame_data->renderbuffer);
 
 	pipewire_submit_buffer(output, buffer);
 
 out:
 
+	pixman_region32_fini(&damage);
+
 	weston_output_arm_frame_timer(base, output->finish_frame_timer);
 
 	return 0;

libweston/backend-rdp/rdp.c

@@ -272,24 +272,29 @@ rdp_output_start_repaint_loop(struct weston_output *output)
 }
 
 static int
-rdp_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
+rdp_output_repaint(struct weston_output *output_base)
 {
 	struct rdp_output *output = container_of(output_base, struct rdp_output, base);
 	struct weston_compositor *ec = output->base.compositor;
 	struct rdp_backend *b = output->backend;
 	struct rdp_peers_item *peer;
+	pixman_region32_t damage;
 
 	assert(output);
 
-	ec->renderer->repaint_output(&output->base, damage,
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
+	ec->renderer->repaint_output(&output->base, &damage,
 				     output->renderbuffer);
 
-	if (pixman_region32_not_empty(damage)) {
+	if (pixman_region32_not_empty(&damage)) {
 		pixman_region32_t transformed_damage;
 		pixman_region32_init(&transformed_damage);
 		weston_region_global_to_output(&transformed_damage,
 					       output_base,
-					       damage);
+					       &damage);
 		wl_list_for_each(peer, &b->peers, link) {
 			if ((peer->flags & RDP_PEER_ACTIVATED) &&
 			    (peer->flags & RDP_PEER_OUTPUT_ENABLED)) {
@@ -299,6 +304,8 @@ rdp_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
 		pixman_region32_fini(&transformed_damage);
 	}
 
+	pixman_region32_fini(&damage);
+
 	weston_output_arm_frame_timer(output_base, output->finish_frame_timer);
 
 	return 0;

libweston/backend-vnc/vnc.c

@@ -1004,10 +1004,11 @@ vnc_output_start_repaint_loop(struct weston_output *output)
 }
 
 static int
-vnc_output_repaint(struct weston_output *base, pixman_region32_t *damage)
+vnc_output_repaint(struct weston_output *base)
 {
 	struct vnc_output *output = to_vnc_output(base);
 	struct vnc_backend *backend = output->backend;
+	pixman_region32_t damage;
 
 	assert(output);
 
@@ -1016,10 +1017,16 @@ vnc_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 
 	vnc_output_update_cursor(output);
 
-	if (pixman_region32_not_empty(damage)) {
-		vnc_update_buffer(output->display, damage);
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(base, &damage);
+
+	if (pixman_region32_not_empty(&damage)) {
+		vnc_update_buffer(output->display, &damage);
 	}
 
+	pixman_region32_fini(&damage);
+
 	/*
 	 * Make sure damage of this (or previous) damage is handled
 	 *

libweston/backend-wayland/wayland.c

@@ -498,22 +498,28 @@ wayland_output_start_repaint_loop(struct weston_output *output_base)
 
 #ifdef ENABLE_EGL
 static int
-wayland_output_repaint_gl(struct weston_output *output_base,
-			  pixman_region32_t *damage)
+wayland_output_repaint_gl(struct weston_output *output_base)
 {
 	struct wayland_output *output = to_wayland_output(output_base);
 	struct weston_compositor *ec;
+	pixman_region32_t damage;
 
 	assert(output);
 
 	ec = output->base.compositor;
 
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
 	output->frame_cb = wl_surface_frame(output->parent.surface);
 	wl_callback_add_listener(output->frame_cb, &frame_listener, output);
 
 	wayland_output_update_gl_border(output);
 
-	ec->renderer->repaint_output(&output->base, damage, NULL);
+	ec->renderer->repaint_output(&output->base, &damage, NULL);
+
+	pixman_region32_fini(&damage);
 
 	return 0;
 }
@@ -604,17 +610,21 @@ wayland_shm_buffer_attach(struct wayland_shm_buffer *sb,
 }
 
 static int
-wayland_output_repaint_pixman(struct weston_output *output_base,
-			      pixman_region32_t *damage)
+wayland_output_repaint_pixman(struct weston_output *output_base)
 {
 	struct wayland_output *output = to_wayland_output(output_base);
 	struct wayland_backend *b;
 	struct wayland_shm_buffer *sb;
+	pixman_region32_t damage;
 
 	assert(output);
 
 	b = output->backend;
 
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
 	if (output->frame) {
 		if (frame_status(output->frame) & FRAME_STATUS_REPAINT)
 			wl_list_for_each(sb, &output->shm.buffers, link)
@@ -624,10 +634,12 @@ wayland_output_repaint_pixman(struct weston_output *output_base,
 	sb = wayland_output_get_shm_buffer(output);
 
 	wayland_output_update_shm_border(sb);
-	b->compositor->renderer->repaint_output(output_base, damage,
+	b->compositor->renderer->repaint_output(output_base, &damage,
 						sb->renderbuffer);
 
-	wayland_shm_buffer_attach(sb, damage);
+	wayland_shm_buffer_attach(sb, &damage);
+
+	pixman_region32_fini(&damage);
 
 	output->frame_cb = wl_surface_frame(output->parent.surface);
 	wl_callback_add_listener(output->frame_cb, &frame_listener, output);

libweston/backend-x11/x11.c

@@ -429,17 +429,23 @@ x11_output_start_repaint_loop(struct weston_output *output)
 }
 
 static int
-x11_output_repaint_gl(struct weston_output *output_base,
-		      pixman_region32_t *damage)
+x11_output_repaint_gl(struct weston_output *output_base)
 {
 	struct x11_output *output = to_x11_output(output_base);
 	struct weston_compositor *ec;
+	pixman_region32_t damage;
 
 	assert(output);
 
 	ec = output->base.compositor;
 
-	ec->renderer->repaint_output(output_base, damage, NULL);
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
+	ec->renderer->repaint_output(output_base, &damage, NULL);
+
+	pixman_region32_fini(&damage);
 
 	weston_output_arm_frame_timer(output_base, output->finish_frame_timer);
 	return 0;
@@ -498,8 +504,7 @@ set_clip_for_output(struct weston_output *output_base, pixman_region32_t *region
 
 
 static int
-x11_output_repaint_shm(struct weston_output *output_base,
-		       pixman_region32_t *damage)
+x11_output_repaint_shm(struct weston_output *output_base)
 {
 	struct x11_output *output = to_x11_output(output_base);
 	const struct weston_renderer *renderer;
@@ -508,6 +513,7 @@ x11_output_repaint_shm(struct weston_output *output_base,
 	struct x11_backend *b;
 	xcb_void_cookie_t cookie;
 	xcb_generic_error_t *err;
+	pixman_region32_t damage;
 
 	assert(output);
 
@@ -517,9 +523,16 @@ x11_output_repaint_shm(struct weston_output *output_base,
 
 	image = renderer->pixman->renderbuffer_get_image(output->renderbuffer);
 
-	ec->renderer->repaint_output(output_base, damage, output->renderbuffer);
+	pixman_region32_init(&damage);
+
+	weston_output_flush_damage_for_primary_plane(output_base, &damage);
+
+	ec->renderer->repaint_output(output_base, &damage, output->renderbuffer);
+
+	set_clip_for_output(output_base, &damage);
+
+	pixman_region32_fini(&damage);
 
-	set_clip_for_output(output_base, damage);
 	cookie = xcb_shm_put_image_checked(b->conn, output->window, output->gc,
 					pixman_image_get_width(image),
 					pixman_image_get_height(image),

libweston/backend.h

@@ -327,4 +327,8 @@ weston_output_flush_damage_for_plane(struct weston_output *output,
 				     struct weston_plane *plane,
 				     pixman_region32_t *damage);
 
+void
+weston_output_flush_damage_for_primary_plane(struct weston_output *output,
+					     pixman_region32_t *damage);
+
 #endif

libweston/compositor.c

@@ -3384,6 +3384,20 @@ weston_output_flush_damage_for_plane(struct weston_output *output,
 	return changed;
 }
 
+WL_EXPORT void
+weston_output_flush_damage_for_primary_plane(struct weston_output *output,
+					     pixman_region32_t *damage)
+{
+	weston_output_flush_damage_for_plane(output,
+					     &output->primary_plane,
+					     damage);
+
+	if (output->full_repaint_needed) {
+		pixman_region32_copy(damage, &output->region);
+		output->full_repaint_needed = false;
+	}
+}
+
 static int
 weston_output_repaint(struct weston_output *output)
 {
@@ -3392,7 +3406,6 @@ weston_output_repaint(struct weston_output *output)
 	struct weston_animation *animation, *next;
 	struct wl_resource *cb, *cnext;
 	struct wl_list frame_callback_list;
-	pixman_region32_t output_damage;
 	int r;
 	uint32_t frame_time_msec;
 	enum weston_hdcp_protection highest_requested = WESTON_HDCP_DISABLE;
@@ -3464,19 +3477,7 @@ weston_output_repaint(struct weston_output *output)
 
 	output_accumulate_damage(output);
 
-	pixman_region32_init(&output_damage);
-
-	weston_output_flush_damage_for_plane(output, &output->primary_plane,
-					     &output_damage);
-
-	if (output->full_repaint_needed) {
-		pixman_region32_copy(&output_damage, &output->region);
-		output->full_repaint_needed = false;
-	}
-
-	r = output->repaint(output, &output_damage);
-
-	pixman_region32_fini(&output_damage);
+	r = output->repaint(output);
 
 	output->repaint_needed = false;
 	if (r == 0)