https://bugs.freedesktop.org/show_bug.cgi?id=59492
--- Comment #14 from Marek Olšák maraeo@gmail.com --- (In reply to comment #13)
I agree... will be hard to find what is it, i've now tested 7.5.2, 7.0.3, 6.5.1 mesa - that is oldest i could run, and this never worked :(.
Yes, the test was fixed fairly recently in core Mesa: http://cgit.freedesktop.org/mesa/mesa/commit/?id=1bc16bf98a1b5a4cca0c0ae2a80...