Subject: Re: PCI and subsystem IDs.
To: Todd Whitesel <email@example.com>
From: Chris G. Demetriou <firstname.lastname@example.org>
Date: 10/06/1998 16:45:03
Todd Whitesel <email@example.com> writes:
> I think you are correct, although conceivably one day they might be required
> for quirk table purposes.
Hmm. If it's desirable to make a 'generic' quirks table that needs to
differentiate on subsystem vendor ID and subsystem ID, then i think
that it should match all 4 IDs (product/vendor/subsystem/subsystem
vendor), as the puc driver currently does.
> It is also possible that some perverse hardware vendor will make their card
> extremely difficult, and the only method we have for distinguishing their
> hack is to check the subsystem ID.
There apparently exist cases where people have whacked others' chips
to do their bidding, and use subsystem/subsystem vendor to
differentiate. In at least one case that i'm aware of, a 'normal'
driver for an existing relatively generic chip will match (based on
vendor/product ID), but not function correctly because, well, there's
a lot of different stuff. 8-)
In that specific case, if the generic driver is to do anything at all,
it should just reject if subsystem/subsystem vendor match the
'whacked' device's values. Another reasonable approach is to just let
the driver for the 'whacked' device match 'better' than the generic
Chris Demetriou - firstname.lastname@example.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.