From owner-freebsd-current@FreeBSD.ORG Tue Dec 6 22:57:35 2005 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A2E1C16A420 for ; Tue, 6 Dec 2005 22:57:35 +0000 (GMT) (envelope-from julian@elischer.org) Received: from a50.ironport.com (a50.ironport.com [63.251.108.112]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1E77043D7B for ; Tue, 6 Dec 2005 22:57:28 +0000 (GMT) (envelope-from julian@elischer.org) Received: from unknown (HELO [10.251.17.229]) ([10.251.17.229]) by a50.ironport.com with ESMTP; 06 Dec 2005 14:57:28 -0800 X-IronPort-Anti-Spam-Filtered: true Message-ID: <43961758.4020407@elischer.org> Date: Tue, 06 Dec 2005 14:57:28 -0800 From: Julian Elischer User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.11) Gecko/20050727 X-Accept-Language: en-us, en MIME-Version: 1.0 To: current@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: can someone explain...[ PCI interrupts] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Dec 2005 22:57:35 -0000 In short words for the likes of me, Can someone give a quicj roundup on PCI routing in 4.x and -current. Specifically: How much is set up by the BIOS and how much is set up by the OS (4.x and -current). How much of my fondly held knowledge of the old hardware PICS (where an interrupt corresponded to an interrupt line) is now out of date? In this world of multiple PCI to PCI bridges, how much latitude doe the OS have in deciding where an interrupt turns up? (in 4.x and -current) An example is my Dell PE2850 (on 4.x), in which my 4 port ethernet card seems to be assigned irqs 10,14,14,2 in that order sometimes and 16,17,17,2 at others. Who is making those decisions? Is it the BIOS and 4.x is just playing along? Assuming the much maligned "boot interrupt" comes in on irq2, does the OS have the oportunity to put my 4th port somewhere else? On 4.x it collides with one of my ether ports but in -current it doesn't Linux and -current on teh same box a;;ocate way different irqs, and they agree about it.. i.e. Linux and -current assign my 4 port card IRQs 18,19,19,16. Do they agree becasue something else has decided it (the bios again?) or becasue they use the same algorythm to work it out.. Also, if the "boot interrupt" was previously set to 2, is that likely to have changed in -current? Am I now going to get clobbered on IRQ16? If yes, is this something that teh BIOS writers decided, or something that the Motherboard designers decided?