Index: programs/Xserver/hw/xfree86/drivers/ati/radeon_render.c
===================================================================
RCS file: /cvs/xorg/xc/programs/Xserver/hw/xfree86/drivers/ati/radeon_render.c,v
retrieving revision 1.16
diff -p -u -r1.16 radeon_render.c
--- programs/Xserver/hw/xfree86/drivers/ati/radeon_render.c	11 Sep 2005 20:58:53 -0000	1.16
+++ programs/Xserver/hw/xfree86/drivers/ati/radeon_render.c	8 Nov 2005 16:11:54 -0000
@@ -281,11 +281,17 @@ AllocateLinear (
    ScrnInfoPtr pScrn,
    int sizeNeeded
 ){
-    RADEONInfoPtr  info       = RADEONPTR(pScrn);
+   RADEONInfoPtr  info       = RADEONPTR(pScrn);
+   int cpp = info->CurrentLayout.bitsPerPixel / 8;
 
    info->RenderTimeout = currentTime.milliseconds + 30000;
    info->RenderCallback = RenderCallback;
 
+   /* XAA allocates in units of pixels at the screen bpp, so adjust size
+    * appropriately.
+    */
+   sizeNeeded = (sizeNeeded + cpp - 1) / cpp;
+
    if (info->RenderTex) {
 	if (info->RenderTex->size >= sizeNeeded)
 	   return TRUE;