sna: Always readback shadow damage after replacing the buffer

Instead track what we explicitly want to discard for the next operation,
so that we don't have to copy back the whole buffer if we have to
replace the shadow and intend to overwrite it all.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 7 insertions, 8 deletions

diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c
index f53bddee..77d15df0 100644
--- a/src/sna/sna_accel.c
+++ b/src/sna/sna_accel.c
@@ -3726,17 +3726,16 @@ use_gpu_bo:
 		if (flags & IGNORE_CPU) {
 			region.extents = *box;
 			region.data = NULL;
+			if (get_drawable_deltas(drawable, pixmap, &dx, &dy)) {
+				region.extents.x1 += dx;
+				region.extents.x2 += dx;
+				region.extents.y1 += dy;
+				region.extents.y2 += dy;
+			}
+			sna_pixmap_discard_shadow_damage(priv, &region);
 			if (region_subsumes_pixmap(&region, pixmap)) {
 				DBG(("%s: discarding move-to-gpu READ for subsumed pixmap\n", __FUNCTION__));
 				hint = MOVE_WRITE;
-			} else {
-				if (get_drawable_deltas(drawable, pixmap, &dx, &dy)) {
-					region.extents.x1 += dx;
-					region.extents.x2 += dx;
-					region.extents.y1 += dy;
-					region.extents.y2 += dy;
-				}
-				sna_pixmap_discard_shadow_damage(priv, &region);
 			}
 		}