Subject: Re: PCIC: PCI vs. ISA
To: Ken Hornstein <kenh@cmf.nrl.navy.mil>
From: Johnny C. Lam <lamj@stat.cmu.edu>
List: tech-kern
Date: 08/26/1998 12:51:25
> Is this the only PCIC PCI chip?  All of the ones I've seen are CardBus.
> And it's _really_ weird that you don't have an ISA IRQ assigned to
> your card, because that should have already been done for you.
>
> This isn't a "Plug and Play OS" issue by any chance, is it?

I believe it is the only PCIC PCI chip.  At least Cirrus Logic doesn't
make any other kind, despite having a few ISA versions.  All of its
other PCIC PCI chips are indeed CardBus.

>From what I understand of PCI, it is the responsibility of the BIOS,
or whatever your host software, to assign the IRQ to your card.  It
doesn't in my case, a Sharp PC-3040 with Phoenix NoteBIOS v4.0, BIOS
version 1.1d.  When I boot under Windows 95 and check "System
Properties", it indicates that I have a "Plug and Play BIOS", but
there isn't any setup option to turn it off.

It sounds like my BIOS isn't doing what it's supposed to, and I have
to workaround it in the kernel.  What's the best way to do this?  My
guess is that it shouldn't touch the MI code, and I should add a
config option to set the IRQ for the controller.  Would this be
acceptable for submission?

In the process of providing a real MI PCIC PCI attachment, I looked at
CardBus bridges and I think I can get those to work as
i82365-compatible devices attached to the PCI bus, instead of
configuring them through an ISA attachment.  Is this desirable?  I
remember some people talking about getting real CardBus support into
the kernel, so I don't want to encroach on someone else's project.

--
   Johnny C. Lam
   Department of Statistics             lamj@stat.cmu.edu
   Carnegie Mellon University           http://www.stat.cmu.edu/~lamj/

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