https://bugs.freedesktop.org/show_bug.cgi?id=110897
--- Comment #55 from Richard Thier u9vata@gmail.com --- (In reply to Dieter Nützel from comment #53)
If you do NOT 'make mrproper' and change only radeon/amdgpu stuff it should only take some minutes (seconds) on your system/CPU.
I was dumb-enough that last time I have cleaned the kernel build dir of mine to save some space haha. This way it took around 50 minutes.
This seems to be the real core of the issue.
We hear from you. ;-)
I am testing right now, at least the system and X have started but will try some games and look for what the logs say. I have also added some extra logging for my liking just to gain more insightful information as I actually have two ideas for fixing this.