From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 10 Aug 2001 05:25:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 10 Aug 2001 05:25:08 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:56937 "EHLO flinx.biederman.org") by vger.kernel.org with ESMTP id ; Fri, 10 Aug 2001 05:24:59 -0400 To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] parport_pc.c PnP BIOS sanity check In-Reply-To: <9ksclk$k45$1@cesium.transmeta.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: 10 Aug 2001 03:18:22 -0600 In-Reply-To: <9ksclk$k45$1@cesium.transmeta.com> Message-ID: User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.5 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "H. Peter Anvin" writes: > 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... If we are going to list all of the silly assumptions, we still have the assumption that 640KB-1MB on x86 cannot be used as ram. It is less painful but still annoying when you put perfectly valid ram there. :) Eric