Hello.
If you're using an AMD GPU, you won't be able to shutdown or reboot correctly your computer.
This is a known issue on kernel bug tracker : https://bugzilla.kernel.org/show_bug.cgi?id=207331
And I reported it on Archlinux bug tracker too: https://bugs.archlinux.org/task/66305
I tested proposed patch, and it works. So let's hope for a fixed kernel either from kernel hackers or Archlinux maintainers.
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