https://bugs.freedesktop.org/show_bug.cgi?id=72685
--- Comment #22 from smoki smoki00790@gmail.com ---
And he said chips handle these cases, no driver need to somhow check for those. I gueesed that maybe that "Stencil op fail or zfail is not KEEP" is culprit but who knows :)
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Depth_in-dept...
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Depth_in-dept...