Comment 151 for bug 1068404

Stefan,

The new issue is caused by Intel driver change to map the GTT aperture (bottom half of BAR 1) as WC, while the top half of BAR1 is still Un-Cacheable. Then the conflict happens when fglrx driver maps the whole BAR1 of Intel IGP device. We have already prepared a fix for this, which should be available in Catalyst 13.3. As a workaround before that, I think you can do some change in Intel graphics driver to map GTT aperture as Un-Cacheable.

Some more information about this for the Intel driver change can be found at https://bugs.freedesktop.org/show_bug.cgi?id=55834 and https://patchwork.kernel.org/patch/1309531/