From 11f971c18ebad912d2bf3022fe62aa804a59c274 Mon Sep 17 00:00:00 2001
From: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Date: Thu, 22 Nov 2012 15:57:00 +0200
Subject: [PATCH] compositor: Move clearing of primary plane damage to the
 backends

Backends may move surfaces to different planes, in which case damage is
generated in the primary plane. This damage is usually passed to the
renderer, but in some cases the backend may decide to not render
anything (that's the case when drm compositor scans out a client
buffer). In that case the damage on the primary plane would be
discarded, leading to artifacts later.

This patch makes the backend's responsibility to clear the damage on
the primary plane, so that unrendered damage is kept for as long as
necessary.
---
 src/compositor-android.c | 4 ++++
 src/compositor-drm.c     | 3 +++
 src/compositor-wayland.c | 4 ++++
 src/compositor-x11.c     | 3 +++
 src/compositor.c         | 2 --
 5 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/compositor-android.c b/src/compositor-android.c
index 3c0273a16..a55c9b0a1 100644
--- a/src/compositor-android.c
+++ b/src/compositor-android.c
@@ -128,10 +128,14 @@ android_output_repaint(struct weston_output *base, pixman_region32_t *damage)
 {
 	struct android_output *output = to_android_output(base);
         struct android_compositor *compositor = output->compositor;
+	struct weston_plane *primary_plane = &compositor->base.primary_plane;
 	struct wl_event_loop *loop;
 
 	compositor->base.renderer->repaint_output(&output->base, damage);
 
+	pixman_region32_subtract(&primary_plane->damage,
+				 &primary_plane->damage, damage);
+
 	/* FIXME: does Android have a way to signal page flip done? */
 	loop = wl_display_get_event_loop(compositor->base.wl_display);
 	wl_event_loop_add_idle(loop, android_finish_frame, output);
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 2dca85c92..8956c8cbf 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -330,6 +330,9 @@ drm_output_render(struct drm_output *output, pixman_region32_t *damage)
 
 	ec->renderer->repaint_output(&output->base, damage);
 
+	pixman_region32_subtract(&ec->primary_plane.damage,
+				 &ec->primary_plane.damage, damage);
+
 	bo = gbm_surface_lock_front_buffer(output->surface);
 	if (!bo) {
 		weston_log("failed to lock front buffer: %m\n");
diff --git a/src/compositor-wayland.c b/src/compositor-wayland.c
index 56759fc0d..d42d56f1a 100644
--- a/src/compositor-wayland.c
+++ b/src/compositor-wayland.c
@@ -311,6 +311,10 @@ wayland_output_repaint(struct weston_output *output_base,
 	wl_callback_add_listener(callback, &frame_listener, output);
 
 	ec->renderer->repaint_output(&output->base, damage);
+
+	pixman_region32_subtract(&ec->primary_plane.damage,
+				 &ec->primary_plane.damage, damage);
+
 }
 
 static void
diff --git a/src/compositor-x11.c b/src/compositor-x11.c
index c575f25ed..20aede813 100644
--- a/src/compositor-x11.c
+++ b/src/compositor-x11.c
@@ -363,6 +363,9 @@ x11_output_repaint(struct weston_output *output_base,
 
 	ec->renderer->repaint_output(output_base, damage);
 
+	pixman_region32_subtract(&ec->primary_plane.damage,
+				 &ec->primary_plane.damage, damage);
+
 	wl_event_source_timer_update(output->finish_frame_timer, 10);
 }
 
diff --git a/src/compositor.c b/src/compositor.c
index 55d206068..5da3925f0 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -985,8 +985,6 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
 	pixman_region32_init(&output_damage);
 	pixman_region32_intersect(&output_damage,
 				  &ec->primary_plane.damage, &output->region);
-	pixman_region32_subtract(&ec->primary_plane.damage,
-				 &ec->primary_plane.damage, &output->region);
 
 	if (output->dirty)
 		weston_output_update_matrix(output);