https://bugs.freedesktop.org/show_bug.cgi?id=64913
--- Comment #9 from Krzysztof A. Sobiecki sobkas@gmail.com --- Compile mesa, make it usable in a system, run piglit, apply the patch, compile mesa,run KSP to check out if it fixes the problem, run piglit again and report regressions. That should be good enough. I hope.