Comment # 91 on bug 69723 from Alex Deucher

(In reply to comment #88)
> Forget that... locked as always.
> 
> I'll test 3.14 soon, either from Alex's drm-next or when we'll get
> 3.14-rc1...

Have you tried disabling hyperz globally rather than just for a specific app? 
E.g., set env var R600_DEBUG=nohyperz in /etc/environment or however your
distro handles global env vars.