diff -urN a/src/mesa/drivers/dri/radeon/radeon_blit.c b/src/mesa/drivers/dri/radeon/radeon_blit.c
--- a/src/mesa/drivers/dri/radeon/radeon_blit.c	2012-03-22 17:10:07.000000000 +0000
+++ b/src/mesa/drivers/dri/radeon/radeon_blit.c	2012-07-02 18:06:56.207935076 +0100
@@ -364,6 +364,9 @@
     if (!r100_check_blit(dst_mesaformat, dst_pitch))
         return GL_FALSE;
 
+    if ((src_width == 2048) || (src_height == 2048))
+        WARN_ONCE ("Source width and/or height = 2048 which may cause graphical glitches.\n");
+
     /* Make sure that colorbuffer has even width - hw limitation */
     if (dst_pitch % 2 > 0)
         ++dst_pitch;