https://bugs.freedesktop.org/show_bug.cgi?id=65192
--- Comment #8 from Michel Dänzer michel@daenzer.net --- (In reply to comment #8)
[...] the bug (or regression, I think it used to work about 2 months ago)
Can you try confirming that, e.g. by trying Mesa from the 9.1 branch or an older snapshot from master?