I am running an AMD Ryzen 2400G, using its integrated graphics in the Linux
host and a gtx 1070 bound to VFIO for virtualized passthrough.  When I boot
with a kernel fetched from git using amd-dri-next on 4.16, it halts the booting
process, usually somewhere around when it checks UTMP. It does not lock up my
keyboard lights, but nothing is displayed on the screen, it does respond to
control-alt-delete. My system is set up to boot to the command line, I use X11
from there with "startx" usually; when the system completes boot of course.