Edit to my above statement about the amd-staging-drm-next kernel working. Either, I had forgotten to return the raven_dmcu.bin file to it's appropriate folder when I tested it, or upgrading my bios to F.20 messed it up again. I'm now back at the point I was before (Same as comment #24). If Magic SysReq is enabled on the system it can be used to reboot the system safely rather than a hard powerdown.