Thanks Clemens,
you wrote in an unrelated thread:
dmesg | grep -i hpet
I wasn't clever enough to use -i (ignore case) when I checked whether
hpet=force worked.
$ dmesg | grep -i hpet
Kernel command line: root=/dev/disk/by-uuid/3e47466f-5ca1-499b-85fc-152074f36364 ro
hpet=force
pci 0000:00:11.0: Failed to force enable HPET
/dev/hpet was still created, but when I changed its group and told jack
to use it I got:
This system has no accessible HPET device (Device or resource busy)
My interpretation of this is that my motherboard is simply too old and
simply doesn't have a hpet timer.
Thanks for the help everyone,
guess I'm out of this until I manage to get a new machine.
Best regards,
Philipp