When I boot Linux 5.10.0-0.bpo.5-amd64 which is my regular kernel sometimes says the below
[. 0.315178] ACPI BIOS Error (bug): Failure creating named object [_SB.WMID], AE_ALREADY_EXISTS (20200925/dswload2-327dswload2-327)
[. 0.315187] ACPI Error: AE_ALREADY_EXISTS, During name lookup/catalog (20200925psobject-221)
[ 1.582157] pci 0000:00.2: AMD-Vi: Unable to read/write to IOMMU perf counter
BusyBox v1.30.1 (Debian 1:1.30.1-4) built-in shell (ash)
Enter 'help' for a list of built-in commands.
The third error message doesn't appear all the time though. Only 2 out of 5 times it will appear.
Linux 5.6.0-0.bpo.2-amd64 gives me a much longer error and won't boot at all either.