https://bugs.freedesktop.org/show_bug.cgi?id=65963

--- Comment #15 from Michel Dänzer michel@daenzer.net --- (In reply to comment #4)

This has recently returned.

[...]

Using Arch Linux 3.15.3.

Note that there are known stability issues in 3.15.y kernels which are fixed in 3.16-rc7 or later.