I met this problem yesterday but on the dailybuid HEAD-200711230002Z,
so now I think I can try to disable the apm and get more info.

2007/11/25, Chavdar Ivanov <ci4ic4@gmail.com>:
> i3856 -current cvs -dPA from about an hour ago. GENERIC.MP+DRI.
>
> kernel hard-locks after printing 'apm on acpi' message. Only power
> switch saves.
>
> Dmesg with apm disabled attached.
>
> I *think* I saw something similar recently in -current; also see
> http://mail-index.netbsd.org/port-i386/2007/11/19/0003.html , although
> here it seems we have 4RC2.
>
> Otherwise seems to be working fine, including DRI (which is what
> causes me trouble from time to time jumping from one to other -current
> version).
>
> Another issue - seen commented by others as well - is the occasional
> ...
> pms0: pms_input: unusual delay (0.079999 s), scheduling reset
> ...
>
>
> --
> /dev/random says:
>        Did you expect mere proof to sway my opinion?
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