Hi,

I've had the same 'Decrementer exception' problem that
a few others have reported with powerbook G4 systems, and
recently noticed that in
OpenBSD:/usr/src/sys/arch/macppc/stand/Locore.c

a recent commit,

http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/macppc/stand/ 
Locore.c?rev=1.13&content-type=text/x-cvsweb-markup

had the message,

"Enable workaround for decrementer exception problem."

and in that code there's the following comment,

         /* this hack is to prevent unexpected Decrementer Exceptions
          * when Apple openfirmware enables interrupts
          */

in the patch_dec_intr routine.

It's not obvious to me that there's any corresponding
hack in the NetBSD codebase, but would anyone care to venture
an opinion on the appropriateness of this hack for the NetBSD
code base, given the issues that I, among others, have seen.

- Mark