Comment 28 for bug 1899336

Okay, I now tried several times.

With kernel 5.9.0:

- Boot 1: Boots up completely, system functional.
- Boot 2: Boots to login screen, crashes after login.
- Boot 3: Crashes before LUKS unlock.
- Boot 4: Boots to login screen, crashes after login.
- Boot 5: Boots to login screen, crashes after login.
- Boot 6: Boots to login screen, crashes after login.
- Boot 7: Crashes before LUKS unlock.
- Boot 8: Boots to login screen, crashes after login.
- Boot 9: Boots to login screen, crashes after login.
- Boot 10: Boots to login screen, crashes after login.
- Boot 11: Crashes before LUKS unlock.
- Boot 12: Boots to login screen, crashes after login.
- Boot 13: Boots to login screen, crashes after login.
- Boot 14: Boots to login screen, crashes after login.
- Boot 15: Boots to login screen, crashes after login.

Completely unusable.

Then I tried removing the "amdgpu.exp_hw_support=1" kernel argument. On kernel 5.9.0, this changed nothing. The system kept crashing during boot.

On kernel 5.4.0-51, it appears that I get a functional system (albeit without multi-monitor support) when I remove this argument. (I'm now posting with this argument removed and booted into 5.4.0-51 kernel.)

So it appears that the "amdgpu" module is the culprit here and that on kernel 5.9.0, it is on by default and no longer requires that argument? (Well, that should really be changed before 5.9.0 becomes "productive", since it will probably render "Renoir"-based systems unusable.)

Unfortunately, I cannot really tell what happens when the system crashes, because I cannot do a "dmesg" on a locked-up system.

Another thing I found recently is that, after boot, Budgie Panel often does not display. I then have to do a "budgie-panel --replace --reset & disown budgie-panel" in the Terminal. But the two issues are probably not related, other than popping up at a similar point in time. Budgie Panel is also not there when "amdgpu" is not in "experimental mode".