From a86dd529e9deaba61aee220d79ac607abbcb5dc6 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Fri, 6 Feb 2009 06:34:35 +0100
Subject: [PATCH] Eliminate the shadow clear on transform change

When the crtc transformation changes, the entire crtc must be repainted.
This was being done by clearing the shadow and then painting the rectangle
containing the screen image; the clear being required as the screen image
may not fill the crtc. When changing the transform rapidly, this leads to
flashing. Eliminate the clear by painting the entire crtc instead of just
the screen rectangle.

(cherry picked fom commit 5394b7e66224d20888dd4020f5cb8ca930720fb4)

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 hw/xfree86/modes/xf86Crtc.h   |  4 ++++
 hw/xfree86/modes/xf86Rotate.c | 39 ++++++++++++++++++++++-------------
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/hw/xfree86/modes/xf86Crtc.h b/hw/xfree86/modes/xf86Crtc.h
index 6761f6ed3..0a596bc49 100644
--- a/hw/xfree86/modes/xf86Crtc.h
+++ b/hw/xfree86/modes/xf86Crtc.h
@@ -337,6 +337,10 @@ struct _xf86Crtc {
     BoxRec          panningTotalArea;
     BoxRec          panningTrackingArea;
     INT16           panningBorder[4];
+    /**
+     * Clear the shadow
+     */
+    Bool	    shadowClear;
 };
 
 typedef struct _xf86OutputFuncs {
diff --git a/hw/xfree86/modes/xf86Rotate.c b/hw/xfree86/modes/xf86Rotate.c
index 66d97a9fb..9f573940d 100644
--- a/hw/xfree86/modes/xf86Rotate.c
+++ b/hw/xfree86/modes/xf86Rotate.c
@@ -113,22 +113,33 @@ xf86RotateCrtcRedisplay (xf86CrtcPtr crtc, RegionPtr region)
 	SetPicturePictFilter (src, crtc->filter,
 			      crtc->params, crtc->nparams);
 
-    while (n--)
+    if (crtc->shadowClear)
     {
-	BoxRec	dst_box;
-
-	dst_box = *b;
-	dst_box.x1 -= crtc->filter_width >> 1;
-	dst_box.x2 += crtc->filter_width >> 1;
-	dst_box.y1 -= crtc->filter_height >> 1;
-	dst_box.y2 += crtc->filter_height >> 1;
-	pixman_f_transform_bounds (&crtc->f_framebuffer_to_crtc, &dst_box);
 	CompositePicture (PictOpSrc,
 			  src, NULL, dst,
-			  dst_box.x1, dst_box.y1, 0, 0, dst_box.x1, dst_box.y1,
-			  dst_box.x2 - dst_box.x1,
-			  dst_box.y2 - dst_box.y1);
-	b++;
+			  0, 0, 0, 0, 0, 0,
+			  crtc->mode.HDisplay, crtc->mode.VDisplay);
+	crtc->shadowClear = FALSE;
+    }
+    else
+    {
+	while (n--)
+	{
+	    BoxRec	dst_box;
+
+	    dst_box = *b;
+	    dst_box.x1 -= crtc->filter_width >> 1;
+	    dst_box.x2 += crtc->filter_width >> 1;
+	    dst_box.y1 -= crtc->filter_height >> 1;
+	    dst_box.y2 += crtc->filter_height >> 1;
+	    pixman_f_transform_bounds (&crtc->f_framebuffer_to_crtc, &dst_box);
+	    CompositePicture (PictOpSrc,
+			      src, NULL, dst,
+			      dst_box.x1, dst_box.y1, 0, 0, dst_box.x1, dst_box.y1,
+			      dst_box.x2 - dst_box.x1,
+			      dst_box.y2 - dst_box.y1);
+	    b++;
+	}
     }
     FreePicture (src, None);
     FreePicture (dst, None);
@@ -192,7 +203,7 @@ xf86CrtcDamageShadow (xf86CrtcPtr crtc)
     DamageRegionAppend (&(*pScreen->GetScreenPixmap)(pScreen)->drawable,
 			&damage_region);
     REGION_UNINIT (pScreen, &damage_region);
-    xf86CrtcShadowClear (crtc);
+    crtc->shadowClear = TRUE;
 }
 
 static void