I purchased an Sapphire Radeon RX 460 card for my Loki machine, installed it and booted. I can log in fine but my machine does not detect my dual displays, one currently mirrors the other one.
I tried to install the AMDGPU-PRO drivers, got the unsupported OS error, changed all of my system information to look like a vanilla Ubuntu machine, the successfully installed the drivers.
After rebooting I get dual blackscreens except for my mouse pointer. Then I uninstalled the AMDGPU-PRO drivers and I'm back to my 1 monitor problem. I've tried installing the oibaf drivers but that didn't fix the issue.
When I check software-properties-gtk I get "no proprietary drivers in use".
lspci shows the following entry:
02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 67ef (rev cf)