From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 8 Aug 2001 17:58:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 8 Aug 2001 17:58:36 -0400 Received: from neon-gw.transmeta.com ([63.209.4.196]:27923 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Wed, 8 Aug 2001 17:58:25 -0400 To: linux-kernel@vger.kernel.org From: "H. Peter Anvin" Subject: Re: [PATCH] parport_pc.c PnP BIOS sanity check Date: 8 Aug 2001 14:58:12 -0700 Organization: Transmeta Corporation, Santa Clara CA Message-ID: <9ksclk$k45$1@cesium.transmeta.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Disclaimer: Not speaking for Transmeta in any way, shape, or form. Copyright: Copyright 2001 H. Peter Anvin - All Rights Reserved Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Followup to: By author: Alan Cox In newsgroup: linux.dev.kernel > > > The following would seem to be required to protect against > > the case in which PnP BIOS reports an IRQ of 0 for a > > parport with disabled IRQ. // Thomas jdthood_AT_yahoo.co.uk > > IRQ 0 is a legal valid IRQ. I suspect the problem is that pnpbios shouldnt > be reporting an IRQ or we should be using some kind of NO_IRQ cookie > IRQ 0 is hardwired to the system timer in PC systems, though, so it could simply be assumed that IRQ 0 will never be used for any other purposes. Reminds me back in the days when you had to worry about DRQs as well; DRQ 0 was hardwired in the original PC but then became available in the AT; there was a whole bunch of things that assumed DRQ 0 wasn't usable, even though it was perfectly fine. Not to mention the motherboard I had which would lock up solid if anything ever used DRQ 5. Good riddance, all this crap... -hpa -- at work, in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt