Date: Thu, 11 Sep 1997 17:39:34 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: thorpej@nas.nasa.gov Cc: mike@smith.net.au, luigi@labinfo.iet.unipi.it, freebsd-hackers@FreeBSD.ORG Subject: Re: PnP support Message-ID: <199709111739.KAA22666@usr07.primenet.com> In-Reply-To: <199709111109.EAA19340@lestat.nas.nasa.gov> from "Jason Thorpe" at Sep 11, 97 04:09:49 am
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> For those wondering why it's problematic, you should take a look at > an AlphaServer 8400 sometime - it can have multiple primary PCI busses, > each with its own physical address space, and each of these primary > PCI busses can host an EISA/ISA bus. NetBSD runs on this system, but > it wouldn't have been possible if we hadn't paid careful attention to > getting bus space accounting right. Yes. Back when the FreeBSD PCI code was just reaching it's first revision of maturity, thanks to Stefan, Jeffrey Hsu and I both had loaner Alpha machines. The discussion between us and CGD of NetBSD about ISA busses bridged off of PCI busses on Alpha instead of vice versa was a big cognitive leap for people not used to the idea of "it has ISA and PCI busses, but the ISA bus is bridged off the PCI, not vice versa". The idea of the PCI being inferiorly linked off the ISA was just too well ingrained in the Intel mindset. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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