hw.pci.allow_unsupported_io_range

[M. Warner Losh]

In message: <2435.67.167.52.21.1095741044.squirrel at www.l-i-e.com>
            "Richard Lynch" <ceo at l-i-e.com> writes:
: I'd really like to RTFM on hw.pci.allow_unsupported_io_range to find out
: exactly what it means.
: 
: I mean, I'm sure it makes sense to the guy who wrote it, but if something
: is both unsupported and allowed, I'm sure not real clear on what that
: means...

It means 'turn off sanity checking for pci bridges when it comes to
resources passing through the bridges.'  It was an ugly hack which was
taken out behind the woodshed and shot.  The problem was that there
are a number of host bridges, which do pass the entire address space
through that didn't mark themselves as negatively decoding bridges.
You need to set it if you have one of the bridges that is like.

Warner