From owner-freebsd-smp Mon Apr 14 21:26:20 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id VAA13128 for smp-outgoing; Mon, 14 Apr 1997 21:26:20 -0700 (PDT) Received: from INET-02-IMC.microsoft.com (mail2.microsoft.com [131.107.3.42]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id VAA13122 for ; Mon, 14 Apr 1997 21:26:18 -0700 (PDT) Received: by mail2.microsoft.com with Internet Mail Service (5.0.1458.8) id <29WMYYB7>; Mon, 14 Apr 1997 21:21:41 -0700 Message-ID: <7D06B4AA8B39D011A64900805F682CDA01001D72@RED-09-MSG.dns.microsoft.com> From: Arlie Davis To: "'Doug Russell'" , Kevin Van Maren Cc: terry@lambert.org, freebsd-smp@freebsd.org Subject: RE: Tyan ATX 1668 Date: Mon, 14 Apr 1997 17:09:05 -0700 X-Priority: 3 X-Mailer: Internet Mail Service (5.0.1458.8) Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Or if the drivers correctly support INT / IRQ sharing, the way God intended PCI drivers to work. My copy of the PCI 2.x spec says that INTs should always always always be shareable. The whole idea of having four INTs is to _reduce_ but not _eliminate_ INT channel sharing. For example, a downstream PCI bus (behind a PCI-to-PCI bridge) could have four PCI slots, each with four INTs. (The INTs would be shared in the usual round-robin fashion.) The INTs from that downstream bus are propagated upward to the main PCI bus onto the four INTs of the hosting PCI slot. This is why the Adaptec 3940 is so mind-blowing at first. But the idea is that you still _have to support_ INT sharing to fully support PCI. So, having five PCI slots is completely "legitimate". You should be able to put a PCI card in both slot 4 and 5 which both use INT A (or any common PCI INT) and it _should_ work just fine. It doesn't, of course, under most Intel-architecture OSes. -- arlie > -----Original Message----- > From: Doug Russell [SMTP:drussell@saturn-tech.com] > Sent: Monday, April 14, 1997 4:07 PM > To: Kevin Van Maren > Cc: terry@lambert.org; freebsd-smp@freebsd.org > Subject: Re: Tyan ATX 1668 > > > > Huh? > > > > There *are* *5* slots. > > Look at http://www.tyan.com/html/s166{2,8}.html for a picture. > > Physically there are 5 slots, but electrically slot 4 and 5 are the > same. > The PCI slots have 4 interrupts, each slot being rotated one further > down > the interrupt chain. Slot 5 is just another slot 4, which, does work > just > fine under virtually any circumstance if you use one of them for a > video > card or something else that doesn't need an interrupt line. > > Later...... > >