compositor: finish frame if redraw fails

If we are about to finish a frame, but a redraw is pending and we let the
compositor redraw, we need to check for errors. If the redraw fails and
the backend cannot schedule a page-flip, we need to finish the frame,
anyway.

All backends except DRM use a timer to schedule frames. Hence, they cannot
fail. But for DRM, we need to be able to handle drmModePageFlip() failures
in case access got revoked.

This fixes a bug where logind+drm caused keyboard input to be missed as we
didn't reenable it after a failed page-flip during deactivation.

src/compositor-drm.c

@@ -576,7 +576,7 @@ drm_output_set_gamma(struct weston_output *output_base,
 		weston_log("set gamma failed: %m\n");
 }
 
-static void
+static int
 drm_output_repaint(struct weston_output *output_base,
 		   pixman_region32_t *damage)
 {
@@ -588,12 +588,12 @@ drm_output_repaint(struct weston_output *output_base,
 	int ret = 0;
 
 	if (output->destroy_pending)
-		return;
+		return -1;
 
 	if (!output->next)
 		drm_output_render(output, damage);
 	if (!output->next)
-		return;
+		return -1;
 
 	mode = container_of(output->base.current_mode, struct drm_mode, base);
 	if (!output->current) {
@@ -603,7 +603,7 @@ drm_output_repaint(struct weston_output *output_base,
 				     &mode->mode_info);
 		if (ret) {
 			weston_log("set mode failed: %m\n");
-			return;
+			goto err_pageflip;
 		}
 		output_base->set_dpms(output_base, WESTON_DPMS_ON);
 	}
@@ -612,7 +612,7 @@ drm_output_repaint(struct weston_output *output_base,
 			    output->next->fb_id,
 			    DRM_MODE_PAGE_FLIP_EVENT, output) < 0) {
 		weston_log("queueing pageflip failed: %m\n");
-		return;
+		goto err_pageflip;
 	}
 
 	output->page_flip_pending = 1;
@@ -664,7 +664,15 @@ drm_output_repaint(struct weston_output *output_base,
 		output->vblank_pending = 1;
 	}
 
-	return;
+	return 0;
+
+err_pageflip:
+	if (output->next) {
+		drm_output_release_fb(output, output->next);
+		output->next = NULL;
+	}
+
+	return -1;
 }
 
 static void

src/compositor-fbdev.c

@@ -196,7 +196,7 @@ fbdev_output_repaint_pixman(struct weston_output *base, pixman_region32_t *damag
 	                             1000000 / output->mode.refresh);
 }
 
-static void
+static int
 fbdev_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 {
 	struct fbdev_output *output = to_fbdev_output(base);
@@ -214,6 +214,8 @@ fbdev_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 		wl_event_source_timer_update(output->finish_frame_timer,
 	                             1000000 / output->mode.refresh);
 	}
+
+	return 0;
 }
 
 static int

src/compositor-headless.c

@@ -60,7 +60,7 @@ finish_frame_handler(void *data)
 	return 1;
 }
 
-static void
+static int
 headless_output_repaint(struct weston_output *output_base,
 		       pixman_region32_t *damage)
 {
@@ -74,7 +74,7 @@ headless_output_repaint(struct weston_output *output_base,
 
 	wl_event_source_timer_update(output->finish_frame_timer, 16);
 
-	return;
+	return 0;
 }
 
 static void

src/compositor-rdp.c

@@ -302,7 +302,7 @@ rdp_output_start_repaint_loop(struct weston_output *output)
 	weston_output_finish_frame(output, msec);
 }
 
-static void
+static int
 rdp_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
 {
 	struct rdp_output *output = container_of(output_base, struct rdp_output, base);
@@ -324,6 +324,7 @@ rdp_output_repaint(struct weston_output *output_base, pixman_region32_t *damage)
 				 &ec->primary_plane.damage, damage);
 
 	wl_event_source_timer_update(output->finish_frame_timer, 16);
+	return 0;
 }
 
 static void

src/compositor-rpi.c

@@ -223,7 +223,7 @@ rpi_output_start_repaint_loop(struct weston_output *output)
 	weston_output_finish_frame(output, time);
 }
 
-static void
+static int
 rpi_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 {
 	struct rpi_output *output = to_rpi_output(base);
@@ -247,6 +247,7 @@ rpi_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 	/* schedule callback to rpi_output_update_complete() */
 	rpi_dispmanx_update_submit(update, output);
 	DBG("frame update submitted\n");
+	return 0;
 }
 
 static void

src/compositor-wayland.c

@@ -212,7 +212,7 @@ wayland_output_start_repaint_loop(struct weston_output *output_base)
 	wl_surface_commit(output->parent.surface);
 }
 
-static void
+static int
 wayland_output_repaint(struct weston_output *output_base,
 		       pixman_region32_t *damage)
 {
@@ -227,7 +227,7 @@ wayland_output_repaint(struct weston_output *output_base,
 
 	pixman_region32_subtract(&ec->primary_plane.damage,
 				 &ec->primary_plane.damage, damage);
-
+	return 0;
 }
 
 static void

src/compositor-x11.c

@@ -326,7 +326,7 @@ x11_output_start_repaint_loop(struct weston_output *output)
 	weston_output_finish_frame(output, msec);
 }
 
-static void
+static int
 x11_output_repaint_gl(struct weston_output *output_base,
 		      pixman_region32_t *damage)
 {
@@ -339,6 +339,7 @@ x11_output_repaint_gl(struct weston_output *output_base,
 				 &ec->primary_plane.damage, damage);
 
 	wl_event_source_timer_update(output->finish_frame_timer, 10);
+	return 0;
 }
 
 static void
@@ -446,7 +447,7 @@ set_clip_for_output(struct weston_output *output_base, pixman_region32_t *region
 }
 
 
-static void
+static int
 x11_output_repaint_shm(struct weston_output *output_base,
 		       pixman_region32_t *damage)
 {
@@ -477,6 +478,7 @@ x11_output_repaint_shm(struct weston_output *output_base,
 	}
 
 	wl_event_source_timer_update(output->finish_frame_timer, 10);
+	return 0;
 }
 
 static int

src/compositor.c

@@ -1365,7 +1365,7 @@ weston_compositor_build_surface_list(struct weston_compositor *compositor)
 	}
 }
 
-static void
+static int
 weston_output_repaint(struct weston_output *output, uint32_t msecs)
 {
 	struct weston_compositor *ec = output->compositor;
@@ -1374,6 +1374,7 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 	struct weston_frame_callback *cb, *cnext;
 	struct wl_list frame_callback_list;
 	pixman_region32_t output_damage;
+	int r;
 
 	/* Rebuild the surface list and update surface transforms up front. */
 	weston_compositor_build_surface_list(ec);
@@ -1404,7 +1405,7 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 	if (output->dirty)
 		weston_output_update_matrix(output);
 
-	output->repaint(output, &output_damage);
+	r = output->repaint(output, &output_damage);
 
 	pixman_region32_fini(&output_damage);
 
@@ -1422,6 +1423,8 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 		animation->frame_counter++;
 		animation->frame(animation, output, msecs);
 	}
+
+	return r;
 }
 
 static int
@@ -1440,15 +1443,16 @@ weston_output_finish_frame(struct weston_output *output, uint32_t msecs)
 	struct weston_compositor *compositor = output->compositor;
 	struct wl_event_loop *loop =
 		wl_display_get_event_loop(compositor->wl_display);
-	int fd;
+	int fd, r;
 
 	output->frame_time = msecs;
 
 	if (output->repaint_needed &&
 	    compositor->state != WESTON_COMPOSITOR_SLEEPING &&
 	    compositor->state != WESTON_COMPOSITOR_OFFSCREEN) {
-		weston_output_repaint(output, msecs);
-		return;
+		r = weston_output_repaint(output, msecs);
+		if (!r)
+			return;
 	}
 
 	output->repaint_scheduled = 0;

src/compositor.h

@@ -219,7 +219,7 @@ struct weston_output {
 	struct wl_list mode_list;
 
 	void (*start_repaint_loop)(struct weston_output *output);
-	void (*repaint)(struct weston_output *output,
+	int (*repaint)(struct weston_output *output,
 			pixman_region32_t *damage);
 	void (*destroy)(struct weston_output *output);
 	void (*assign_planes)(struct weston_output *output);