https://bugs.freedesktop.org/show_bug.cgi?id=84500
--- Comment #22 from Christian König deathsimple@vodafone.de --- Keep in mind that this might actually be a user space problem and that different kernel versions work or don't work only be coincident.
If you can get me an SSH access to the box I could take a look as well. Attaching a debugger to the process in question shouldn't be to hard.