BOUNCE rtl@rtlinux.org: Approval required: Non-member submissionfrom [Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac. (fwd)

[Der Herr Hofrat <der.herr@hofr.at>]

>From owner-rtl Mon Jun 18 02:18:52 2001
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Date: Mon, 18 Jun 2001 10:12:42 +0200 (CEST)
From: Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac.be>
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Reply-To: Herman Bruyninckx <herman.bruyninckx@mech.kuleuven.ac.be>
To: <rtl@fsmlabs.com>
Subject: Re: [rtl] off-topic: PCI interrupts
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On Sun, 17 Jun 2001, Wayne E. Van Loon Sr. wrote:

[...]
> > > IMHO, nothing off topic about your question. In my experience, there are
> > > 4 interrupts available to the PCI bus in PCs. If you have 5 or more PCI
> > > slots, then at least two slots have to share the same interrupt.
> > >
> > Deos this mean that you have to include code in _any_ device driver
> > you write that checks whether the interrupt was really for that device
> > drive?
[...]
> I think I sent you my rtl process / driver for the bt 878 and that is the way
> that driver works. I have 4 ea. bt878 devices in my systems and some of my
> devices always share the same interrupt. In my driver / rtl process, I check
> to see which device caused the interrupt. It may be that two devices will
> have caused the same interrupt by the time that the handler runs and the
> driver / rtl process will want to handle both on the same interrupt.

That means that no device driver code is portable, because you
can't know in advance which other devices got the same interrupt
assigned to them...? I mean: your driver code can only check the
boards it was written for, so what do you do if your ISR is called by
the interrupt but the interrupt is not for your boards?

Are other buses better in this respect?

Herman

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