https://bugs.freedesktop.org/show_bug.cgi?id=90056
--- Comment #6 from Grigori Goronzy greg@chown.ath.cx --- Created attachment 115401 --> https://bugs.freedesktop.org/attachment.cgi?id=115401&action=edit Possible fix
How about this? Not tested yet, I don't have access to a radeon GPU right now.