From 43fffc8ea93bef012928f077981d9bf7bb7c3023 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 27 Jan 2016 10:42:47 +0000
Subject: sna: Perform composite rotation on the individual damage elements

As the rotation may need to perform intermediate copies (e.g. displays
larger than the render pipeline), we can reduce the amount of overdraw
by using the damage boxes rather than preparing to redraw the entire
output.

Reported-by: Frank Delache <franck.delache@grassvalley.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93864
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 src/sna/sna_display.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index 511aa84d..77dd3bed 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -8215,36 +8215,38 @@ sna_crtc_redisplay__composite(xf86CrtcPtr crtc, RegionPtr region, struct kgem_bo
 	ValidatePicture(src);
 	ValidatePicture(dst);
 
-	if (!sna->render.composite(sna,
-				   PictOpSrc, src, NULL, dst,
-				   sx, sy,
-				   0, 0,
-				   0, 0,
-				   crtc->mode.HDisplay, crtc->mode.VDisplay,
-				   COMPOSITE_PARTIAL, memset(&tmp, 0, sizeof(tmp)))) {
-		DBG(("%s: unsupported operation!\n", __FUNCTION__));
-		sna_crtc_redisplay__fallback(crtc, region, bo);
-		goto free_dst;
-	}
-
+	/* Composite each box individually as if we are dealing with a rotation
+	 * on a large display, we may have to perform intermediate copies. We
+	 * can then minimise the overdraw by looking at individual boxes rather
+	 * than the bbox.
+	 */
 	n = region_num_rects(region);
 	b = region_rects(region);
 	do {
-		BoxRec box;
-
-		box = *b++;
+		BoxRec box = *b;
 		transformed_box(&box, crtc);
 
 		DBG(("%s: (%d, %d)x(%d, %d) -> (%d, %d), (%d, %d)\n",
 		     __FUNCTION__,
-		     b[-1].x1, b[-1].y1, b[-1].x2-b[-1].x1, b[-1].y2-b[-1].y1,
+		     b->x1, b->y1, b->x2-b->x1, b->y2-b->y1,
 		     box.x1, box.y1, box.x2, box.y2));
 
-		tmp.box(sna, &tmp, &box);
-	} while (--n);
-	tmp.done(sna, &tmp);
+		if (!sna->render.composite(sna,
+					   PictOpSrc, src, NULL, dst,
+					   sx + box.x1, sy + box.y1,
+					   0, 0,
+					   box.x1, box.y1,
+					   box.x2 - box.x1, box.y2 - box.y1,
+					   0, memset(&tmp, 0, sizeof(tmp)))) {
+			DBG(("%s: unsupported operation!\n", __FUNCTION__));
+			sna_crtc_redisplay__fallback(crtc, region, bo);
+			break;
+		} else {
+			tmp.box(sna, &tmp, &box);
+			tmp.done(sna, &tmp);
+		}
+	} while (b++, --n);
 
-free_dst:
 	FreePicture(dst, None);
 free_src:
 	FreePicture(src, None);
-- 
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