From owner-freebsd-hackers Mon Dec 10 14:39:40 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from mass.dis.org (mass.dis.org [216.240.45.41]) by hub.freebsd.org (Postfix) with ESMTP id CA90E37B405; Mon, 10 Dec 2001 14:39:37 -0800 (PST) Received: from mass.dis.org (localhost [127.0.0.1]) by mass.dis.org (8.11.6/8.11.3) with ESMTP id fBAMj2V03977; Mon, 10 Dec 2001 14:45:02 -0800 (PST) (envelope-from msmith@mass.dis.org) Message-Id: <200112102245.fBAMj2V03977@mass.dis.org> To: Bernd Walter Cc: Danny Braniss , Mike Smith , freebsd-hackers@FreeBSD.ORG, msmith@mass.dis.org Subject: Re: irq In-Reply-To: Message from Bernd Walter of "Mon, 10 Dec 2001 21:59:05 +0100." <20011210215905.E11774@cicely8.cicely.de> Date: Mon, 10 Dec 2001 14:45:02 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > A PCI slot has 4 irq lines named INTA to INTD. > On PCs all slots share the same 4 physical irqs and the lines are > hardwired on the board in alternating order to each slot. Not necessarily. This is the classic barber-pole or "PCI swizzle"; it's not mandated for motherboard designs though (but it is for bridges, since bridges have no other interrupt routing metadata). > If you want cards not to share irqs you have to swap slots until you > get what you want - you can't enforce it with software. This is closer to correct, though still not universally so. Better just to say that PCI interrupt routing is weird, and leave it at that. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message