https://bugs.freedesktop.org/show_bug.cgi?id=31870
--- Comment #4 from Rubén Fernández rubenf3000@gmail.com 2011-01-29 15:43:58 PST --- The kernel patch that fixes bug #33139 also solved this bug for me; it's possible they were the same. Try applying this patch to your kernel:
https://bugs.freedesktop.org/attachment.cgi?id=42615
and see if it helps