Backported from X.org:

 From f93d10ce9bb4a6de83b561f44fb7b046def16234 Mon Sep 17 00:00:00 2001
 From: Daniel Stone <daniel@fooishbar.org>
 Date: Mon, 6 Nov 2006 18:33:45 +0200
 Subject: dix: remove staggeringly broken vendor workarounds
Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>