https://bugs.freedesktop.org/show_bug.cgi?id=59588
--- Comment #5 from Andy Furniss lists@andyfurniss.entadsl.com --- (In reply to comment #3)
As far as I can tell, all shaders end with an export instruction, with EndOfProgram bit set. I suspect an issue with number of color buffer export involved.
Can you apply this patch and report if the game still locks the gpu ?
The game runs OK with the patch.