Comment # 4 on bug 103863 from Benjamin Bellec

I reinstalled Fedora 26 (instead of 27) on my computer, and reinstalled the
kernel 4.15.0-0.rc0.git7.1.fc28.x86_64 on it, and I haven't the error
anymore...

Now I have a display and the HDMI audio on my second screen (TV in fact) is
working.

Also, my F27 computer was on a new Ryzen config, which I finally reverted to
old Core i5 due to global instability.

So I don't know where the problem was...