Yesterday I bought a Radeon RX550 adapter (PCI ID 1002:699f) to replace a dying GeForce for my desktop. It worked OK all day, but when I tried to suspend the system at the end of the day, it failed - the system was left running but unresponsive and had to be reset.

Looking at the logs of the boot which ended with the failed suspend attempt, I see this:

Jun 19 23:00:06 adam.happyassassin.net NetworkManager[1317]: <info>  [1529474406.7296] manager: sleep: sleep requested (sleeping: no  enabled: yes)
Jun 19 23:00:06 adam.happyassassin.net NetworkManager[1317]: <info>  [1529474406.7300] manager: NetworkManager state is now ASLEEP
Jun 19 23:00:06 adam.happyassassin.net gnome-shell[1729]: Screen lock is locked down, not locking
Jun 19 23:00:06 adam.happyassassin.net gnome-shell[1729]: Failed to set power save mode for output DP-1: Permission denied
Jun 19 23:00:06 adam.happyassassin.net gnome-shell[1729]: Failed to set power save mode for output DVI-D-1: Permission denied
Jun 19 23:00:07 adam.happyassassin.net kernel: ------------[ cut here ]------------
Jun 19 23:00:07 adam.happyassassin.net kernel: kernel BUG at drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4708!

...and that's all - the trace I'd expect to follow the 'kernel BUG' line does not appear.

This is on Fedora Rawhide with kernel 4.17.0-0.rc7.git2.2.fc29.x86_64 . The desktop is GNOME on Wayland, and I have two displays attached to the adapter, one via DVI and one via DisplayPort.