https://bugs.freedesktop.org/show_bug.cgi?id=92555
--- Comment #9 from Marek Olšák maraeo@gmail.com --- This might help: https://cgit.freedesktop.org/mesa/mesa/commit/?id=d4d9ec55c589156df4edc227a8...
Although it's an unrelated feature, it changes the allocation function from pipe_buffer_create to r600_aligned_buffer_create. I believe that can fix HyperZ hangs on big GPU.