(In reply to comment #12)
> Created attachment 102075 [details] [review] [review]
> add deep color module option
> 
> This patch disables the deep color support by default which should resolve
> your issue.  You can set radeon.deep_color=1 on the kernel command line in
> grub to re-enable it.  Hopefully we can resolve this properly for 3.17 and
> enable deep color by default.

Indeed it does. I've tested with 3.16-rc4 and all is well again. Sorry for the
delayed reply. If I can be useful in further testing please let me know.
Thanks.