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Date:      Mon, 26 Jun 2000 15:31:32 -0400 (EDT)
From:      Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To:        Nick Hibma <n_hibma@calcaphon.com>
Cc:        Mike Smith <msmith@FreeBSD.ORG>, FreeBSD CURRENT Mailing List <current@FreeBSD.ORG>
Subject:   Re: irunning, width in bits. 
Message-ID:  <200006261931.PAA70567@khavrinen.lcs.mit.edu>
In-Reply-To: <Pine.BSF.4.20.0006261125350.11136-100000@localhost>
References:  <200006260823.BAA00624@mass.osd.bsdi.com> <Pine.BSF.4.20.0006261125350.11136-100000@localhost>

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<<On Mon, 26 Jun 2000 11:29:39 +0100 (BST), Nick Hibma <n_hibma@calcaphon.com> said:

> I guess that the perfect solution is to be able to hardwire the PCI irqs
> in some way once FreeBSD is doing the PnP resource allocation.

On typical non-SMP motherboards, the PCI IRQs are hard-wired on the
motherboard.  That is to say, INTA of slot 13 is wire-OR'd with INTB of
slot 14, is wire-OR'd with INTC of slot 15, is wire-OR'd with INTD of
slot 16, and oh, yeah, is also wire-OR'd with INTA of every
on-motherboard device.

SMP motherboards tend to be significantly better in this regard.

The PCI BIOS includes a function which gives you the map of how
interrupts are wired together.

-GAWollman

--
Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu  | O Siem / The fires of freedom 
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick


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