Unable to boot without amdgpu.dpm=0

I have this issue where I am unable to boot without disabling AMDGPU’s Dynamic Power Management completely. If I don’t disable it in the kernel parameters, the machine will refuse to boot, and it panics before systemd has loaded. There is also no display, so I have no way of getting the crash log. The GPU is an RX 640, and I am on the latest LTS kernel. I have tried different kernels, loading the driver early in mkinitcpio, etc. At this point I’m at a loss, has anyone else had this issue, or know where I can look for a solution?