Just updated to the 4.17-rc0 kernel and it seems the problem has been mostly
fixed there. The patches are no longer needed (already in there) and trying to
reproduce the issue only resulted in a couple of "Failed to get VBLANK!" errors
that aren't fatal.

I'm not certain about the flickering issue I mentioned earlier... It looked
like one but might actually be some kind of sudden color palette distortion.
The problem only appeared since 4.16. I don't recall having the issue in 4.15.

I can partially reproduce it in the Firefox new tab page, by quickly hovering
over the links on the "Top Sites" and "Highlights". The whole screen would turn
a bit darker in color for a very short instant then returns to normal. It
happens randomly and it doesn't seem to produce any errors in the log. Not a
major issue, just it can be annoying sometimes.