For a while there it looked like we might get the DAL work in Linux 4.9, but
now I'm wondering if this is more of a 4.10 or 4.11 thing.
- https://www.phoronix.com/scan.php?page=news_item&px=AMDGPU-Linux-4.9-First

It's actually a pretty exciting time for AMD GPUs on Linux, as it is right in
the middle of a massive overhaul. I purchased a Tonga specifically so I could
bear witness to this open-by-default turnaround for the AMD team.

And yeah, it's totally frustrating the multi-monitor is broken right now, but
at least we get re-clocking. Imagine how frustrating it must be for open-source
nVidia fans right now, with nVidia itself having long stymied the community
work in that area.

With my current setup, I have both monitors connected to my Intel GPU, and the
primary monitor also connected to the AMD one, with Intel being initialised by
EFI / BIOS first. In Linux, I switch the primary monitor to Intel, and for
Windows I switch it back to AMD. Not perfect of course, but this flow sort of
works for me.