From 5394b7e66224d20888dd4020f5cb8ca930720fb4 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.

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 6ca025426..69afaa5d1 100644
--- a/hw/xfree86/modes/xf86Crtc.h
+++ b/hw/xfree86/modes/xf86Crtc.h
@@ -357,6 +357,10 @@ struct _xf86Crtc {
      * Added in ABI version 3
      */
     Bool	    active;
+    /**
+     * Clear the shadow
+     */
+    Bool	    shadowClear;
 };
 
 typedef struct _xf86OutputFuncs {
diff --git a/hw/xfree86/modes/xf86Rotate.c b/hw/xfree86/modes/xf86Rotate.c
index dcc3ec02c..618072ab6 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