From owner-freebsd-current@FreeBSD.ORG Wed Dec 7 20:41:55 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 95A4616A420; Wed, 7 Dec 2005 20:41:55 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from speedfactory.net (mail6.speedfactory.net [66.23.216.219]) by mx1.FreeBSD.org (Postfix) with ESMTP id BABE343D73; Wed, 7 Dec 2005 20:41:47 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (unverified [66.23.211.162]) by speedfactory.net (SurgeMail 3.5b3) with ESMTP id 3338755 for multiple; Wed, 07 Dec 2005 15:43:45 -0500 Received: from localhost (john@localhost [127.0.0.1]) by server.baldwin.cx (8.13.1/8.13.1) with ESMTP id jB7Kfbux062614; Wed, 7 Dec 2005 15:41:37 -0500 (EST) (envelope-from jhb@freebsd.org) From: John Baldwin To: freebsd-current@freebsd.org Date: Wed, 7 Dec 2005 15:33:02 -0500 User-Agent: KMail/1.8.2 References: <018e01c5fafe$c9154a20$642a15ac@smiley> <20051207.105722.60788677.imp@bsdimp.com> <439724E0.3020102@samsco.org> In-Reply-To: <439724E0.3020102@samsco.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200512071533.04396.jhb@freebsd.org> X-Spam-Status: No, score=-2.8 required=4.2 tests=ALL_TRUSTED autolearn=failed version=3.0.2 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on server.baldwin.cx X-Server: High Performance Mail Server - http://surgemail.com r=1653887525 Cc: darren.pilgrim@bitfreak.org, current@freebsd.org, "M. Warner Losh" Subject: Re: can someone explain...[ PCI interrupts] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Dec 2005 20:41:55 -0000 On Wednesday 07 December 2005 01:07 pm, Scott Long wrote: > M. Warner Losh wrote: > > In message: <018e01c5fafe$c9154a20$642a15ac@smiley> > > > > "Darren Pilgrim" writes: > > : From: John Baldwin > > : > > : > The reason [for masking interrupts] is that PCI interrupts are level > > : > triggered, so they won't "shut up" until the ISR has run and pacified > > : > the PCI device. > > : > > : But PCI interrupts can be programmed either level- or edge-triggered, > > : so wouldn't programming to edge-triggered interrupts solve the "they > > : won't shut up" issue? > > > > PCI interrupts are level. There's no way to program them otherwise. > > > > Warner > > While electrically they are level, the APIC can be programmed to pass > them on either level or edge. Once you get into MSI, the distinction > becomes very muddy. That's not for delivery, that's for how the APIC interprets the signals you see. See my earlier e-mail why misprogramming the APIC would hose things. MSI is a whole different ball of wax entirely in that regard. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org