Your probably not going to find much help here. AMD official drivers for open source pretty much stopped at 2015 (IoM) Edition
You can head to open source community for Xorg found HERE
radeon
For alternative find HERE
radeonhd
If your still under a frsh install of Ubuntu
It was developed by the X11 community, mostly centered around Novell and AMD, with the free documentation provided by AMD.
Follow the Alternative commands and report your errors to were Xorg directs it.
This really isn't the OpenSource Support forum, but hope my info helps ya out