https://bugs.freedesktop.org/show_bug.cgi?id=101278
--- Comment #1 from nagrigoriadis@gmail.com --- Apologies, I forgot some important related details:
I'm on kernel 4.11.1-gentoo right now, but observed the same on 4.10.8 libdrm-2.4.80 llvm-4.0.0-r2 xorg-server-1.19.3 xf86-video-ati-7.9.0 using the "radeon" kernel module.