https://bugs.freedesktop.org/show_bug.cgi?id=91202
--- Comment #20 from jokeyrhyme@gmail.com --- 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-Fir...
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.