L4d2 used to work with mesa 10.3, I now have graphical glitches, and it ends up
in GPU hang after ~5min of game.


might be related to https://bugs.freedesktop.org/show_bug.cgi?id=88561


Hardware is Radeon HD7950

llvm 3.7svn, Linux 3.19.0-g18320f2

OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD TAHITI
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.6.0-devel
(git-9216348)
OpenGL core profile shading language version string: 3.30


I'm uploading an apitrace, will add a comment with the link when it's done.