I was asked in https://www.phoronix.com/forums/forum/linux-graphics-x-org-drivers/open-source-amd-linux/1027705-amdgpu-on-linux-4-18-to-offer-greater-vega-power-savings-displayport-1-4-fixes?p=1027933#post1027933 to mention here that I have experienced this kind of bug only when using the "new" display code (amdgpu.dc=1). I cannot strictly rule out that it could also happen with dc=0, since I have tried dc=0 only for short periods occasionally, but during those periods I did not see this kind of crash.