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, 17 Nov 2000 21:41:02 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 17 Nov 2000 21:40:52 -0500 Received: from neon-gw.transmeta.com ([209.10.217.66]:59657 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Fri, 17 Nov 2000 21:40:42 -0500 To: linux-kernel@vger.kernel.org From: "H. Peter Anvin" Subject: Re: VGA PCI IO port reservations Date: 17 Nov 2000 18:10:13 -0800 Organization: Transmeta Corporation, Santa Clara CA Message-ID: <8v4oe5$vbl$1@cesium.transmeta.com> In-Reply-To: <200011172002.UAA01918@raistlin.arm.linux.org.uk> <20001117202009.B2472@zalem.puupuu.org> 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 2000 H. Peter Anvin - All Rights Reserved Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Followup to: <20001117202009.B2472@zalem.puupuu.org> By author: Olivier Galibert In newsgroup: linux.dev.kernel > > What guarantees you that: > 1- No device will respond 0xffff for an address it decodes > 2- No device will crap up on you simply because you've read one > particular address > > If any of these if true for any device out there (I think I have one > in my computer that does the 1/ part in some cases), your code is > unsafe. > It is. There are plenty of devices for which an arbitrary IN is an irrecoverable state transition. -hpa -- at work, in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/