Subset of power patch: subtractive decoding

[M. Warner Losh]

In message: <200401110212.i0B2CD7E029333 at gw.catspoiler.org>
            Don Lewis <truckman at freebsd.org> writes:
: It works on my Thinkpad R40.  I never needed
: hw.pci.allow_unsupported_io_range.  It doesn't eliminate my need for
: hw.cbb.start_memory=0xC0800000 in /boot/loader.conf.  Without this my
: laptop hangs during boot.

Yes.  I have other patches that will fix *THAT* problem, but they have
some minor problems with alignment that I need to fix...

Warner