Why doesn't ppc(4) check non-ENXIO failures during probe?

M. Warner Losh imp at bsdimp.com
Tue Aug 24 04:11:11 UTC 2010

In message: <201008171615.21103.jhb at freebsd.org>
            John Baldwin <jhb at FreeBSD.org> writes:
: >     So more or less it's for BIOSes with ISA that doesn't feature plug
: > and play (286s, 386s, some 486s?)? Just trying to fill in the gap :).
: Yes, it may perhaps still be useful for some x86 embedded systems, though
: it is doubtful that those would use a ppc(4) device perhaps.

Many embedded x86 systems use ppc(4) as a DIO port.  ppi attaches to
it and can be used to frob bits.

These days, of course, almost all boards have ACPI, so that means they
get enumerated that way.  Only boards that don't run windows might not
have ACPI, in which case the devices are usually enumerated via
PNPBIOS.  But not always, since those boards tend to have the buggiest
BIOSes on the planet in this area.  Hints are needed on a few of these
boards since nothing else will work.  And they have Atom processors on


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