As has been indicated previously on this forum,
apm(4) gets first dibs at attaching under most circumstances.
You can disable
apm(4) and use
acpi(4) instead:
boot> boot -c
UKC> disable apm
UKC> quit
Fortunately when you switch to ACPI it generously provides APM emulation so user-land applications can still use the
/dev/{apm,apmctl} interface.
This means those ports should work as intended, as will
apm(8), but you won't see the
apm(4) verbiage in the
dmesg(1) output.
Hope that helps.