commit 2cd8177aec083b939336eec9c050a533e89c2742
Author: Maxim Levitsky <maximlevitsky@gmail.com>
Date:   Fri Aug 5 04:47:29 2011 +0300

    Allow page flipping only for scanout buffer for now
    as simple swapping between off-screen pixmaps confuses compiz because
    there is no syncronization method to tell it about that swap

diff --git a/src/nouveau_dri2.c b/src/nouveau_dri2.c
index 1a68ed3..2081ce2 100644
--- a/src/nouveau_dri2.c
+++ b/src/nouveau_dri2.c
@@ -153,8 +153,7 @@ can_exchange(DrawablePtr draw, PixmapPtr dst_pix, PixmapPtr src_pix)
 
 	}
 
-	return (!nouveau_exa_pixmap_is_onscreen(dst_pix) ||
-		(DRI2CanFlip(draw) && pNv->has_pageflip)) &&
+	return ((DRI2CanFlip(draw) && pNv->has_pageflip)) &&
 		dst_pix->drawable.width == src_pix->drawable.width &&
 		dst_pix->drawable.height == src_pix->drawable.height &&
 		dst_pix->drawable.depth == src_pix->drawable.depth &&