From c2da68871a33612abd8a4fddbabec6118c6ea1be Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 6 Apr 2015 09:52:59 +0100
Subject: [PATCH] sna: Clear the new scanout along all paths before attaching

Make sure we clear the scanout even after the error paths before
attaching the shadow buffer (in case it is full of unwanted junk).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 src/sna/sna_display.c | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index 6f69619f..eacfe146 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -1995,6 +1995,22 @@ get_scanout_bo(struct sna *sna, PixmapPtr pixmap)
 	return priv->gpu_bo;
 }
 
+static void clear(struct sna *sna,
+		  PixmapPtr front, struct kgem_bo *bo,
+		  xf86CrtcPtr crtc)
+{
+	bool ok = false;
+	if (!wedged(sna))
+		ok = sna->render.fill_one(sna, front, bo, 0,
+					  0, 0, crtc->mode.HDisplay, crtc->mode.VDisplay,
+					  GXclear);
+	if (!ok) {
+		void *ptr = kgem_bo_map__gtt(&sna->kgem, bo);
+		if (ptr)
+			memset(ptr, 0, bo->pitch * crtc->mode.HDisplay);
+	}
+}
+
 static struct kgem_bo *sna_crtc_attach(xf86CrtcPtr crtc)
 {
 	struct sna_crtc *sna_crtc = to_sna_crtc(crtc);
@@ -2083,18 +2099,9 @@ force_shadow:
 			if (b.y2 > scrn->virtualY)
 				b.y2 = scrn->virtualY;
 			if (b.x2 - b.x1 < crtc->mode.HDisplay ||
-			    b.y2 - b.y1 < crtc->mode.VDisplay) {
-				bool ok = false;
-				if (!wedged(sna))
-					ok = sna->render.fill_one(sna, front, bo, 0,
-								  0, 0, crtc->mode.HDisplay, crtc->mode.VDisplay,
-								  GXclear);
-				if (!ok) {
-					void *ptr = kgem_bo_map__gtt(&sna->kgem, bo);
-					if (ptr)
-						memset(ptr, 0, bo->pitch * crtc->mode.VDisplay);
-				}
-			}
+			    b.y2 - b.y1 < crtc->mode.VDisplay)
+				clear(sna, front, bo, crtc);
+
 			if (b.y2 > b.y1 && b.x2 > b.x1) {
 				DrawableRec tmp;
 
@@ -2110,12 +2117,14 @@ force_shadow:
 				tmp.depth = front->drawable.depth;
 				tmp.bitsPerPixel = front->drawable.bitsPerPixel;
 
-				(void)sna->render.copy_boxes(sna, GXcopy,
+				if (!sna->render.copy_boxes(sna, GXcopy,
 							     &front->drawable, __sna_pixmap_get_bo(front), 0, 0,
 							     &tmp, bo, -crtc->x, -crtc->y,
-							     &b, 1, 0);
+							     &b, 1, 0))
+					clear(sna, front, bo, crtc);
 			}
-		}
+		} else
+			clear(sna, front, bo, crtc);
 
 		sna_crtc->shadow_bo_width = crtc->mode.HDisplay;
 		sna_crtc->shadow_bo_height = crtc->mode.VDisplay;