https://bugs.freedesktop.org/show_bug.cgi?id=91880
--- Comment #31 from Thomas DEBESSE dev@illwieckz.net --- Hi, it looks like I'm experiencing the same bug (see #93288 ).
I own a radeon 39 R390X manufactured by MSI. Right now I tried the last firmware from git repository but it fixed nothing. (tip for ubuntu users, the package from upcoming xenial is currently shipping the latest hawaii firmwares, I checked them against the latest master: https://launchpad.net/ubuntu/+source/linux-firmware ).
I can send you my dmesg if needed.