Hello,
I get the following kernel panic messages when I shutdown my Ubuntu 18.04.1 installation that runs on a Lenovo ThinkPad E480 that has a Polaris12 GPU. (All the latest updates installed; the shutdown is performed normally via the GNOME Desktop Environment.)
![amd.jpeg amd.jpeg](/t5/image/serverpage/image-id/33835i14EE8087D8916042/image-size/large?v=v2&px=999)