Index: gfx/cairo/cairo/src/cairo-xlib-surface.c
===================================================================
RCS file: /cvsroot/mozilla/gfx/cairo/cairo/src/cairo-xlib-surface.c,v
retrieving revision 1.43
diff -u -p -U 8 -r1.43 cairo-xlib-surface.c
--- gfx/cairo/cairo/src/cairo-xlib-surface.c	8 Apr 2008 20:11:21 -0000	1.43
+++ gfx/cairo/cairo/src/cairo-xlib-surface.c	30 Jun 2008 00:33:12 -0000
@@ -1237,17 +1237,19 @@ _surfaces_compatible (cairo_xlib_surface
     if (!_cairo_xlib_surface_same_screen (dst, src))
 	return FALSE;
 
     /* same depth (for core) */
     if (src->depth != dst->depth)
 	return FALSE;
 
     /* if Render is supported, match picture formats */
-    if (src->xrender_format != NULL && src->xrender_format == dst->xrender_format)
+    if (src->xrender_format != dst->xrender_format)
+	return FALSE;
+    else if (src->xrender_format != NULL)
 	return TRUE;
 
     /* Without Render, match visuals instead */
     if (src->visual == dst->visual)
 	return TRUE;
 
     return FALSE;
 }
Index: gfx/cairo/cairo/src/cairo-xcb-surface.c
===================================================================
RCS file: /cvsroot/mozilla/gfx/cairo/cairo/src/cairo-xcb-surface.c,v
retrieving revision 1.26
diff -u -p -U 8 -r1.26 cairo-xcb-surface.c
--- gfx/cairo/cairo/src/cairo-xcb-surface.c	14 Feb 2008 06:54:27 -0000	1.26
+++ gfx/cairo/cairo/src/cairo-xcb-surface.c	30 Jun 2008 00:33:12 -0000
@@ -874,17 +874,19 @@ _surfaces_compatible (cairo_xcb_surface_
     if (!_cairo_xcb_surface_same_screen (dst, src))
 	return FALSE;
 
     /* same depth (for core) */
     if (src->depth != dst->depth)
 	return FALSE;
 
     /* if Render is supported, match picture formats */
-    if (src->xrender_format.id != XCB_NONE && src->xrender_format.id == dst->xrender_format.id)
+    if (src->xrender_format.id != dst->xrender_format.id)
+	return FALSE;
+    else if (src->xrender_format.id != XCB_NONE)
 	return TRUE;
 
     /* Without Render, match visuals instead */
     if (src->visual == dst->visual)
 	return TRUE;
 
     return FALSE;
 }