Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 6 Nov 2001 14:40:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 6 Nov 2001 14:40:10 -0500 Received: from delta.ds.pg.gda.pl ([213.192.72.1]:16275 "EHLO delta.ds2.pg.gda.pl") by vger.kernel.org with ESMTP id ; Tue, 6 Nov 2001 14:39:54 -0500 Date: Tue, 6 Nov 2001 20:39:12 +0100 (MET) From: "Maciej W. Rozycki" Reply-To: "Maciej W. Rozycki" To: "Randy.Dunlap" cc: robert@schwebel.de, linux-kernel@vger.kernel.org Subject: Re: ioport range of 8259 aka pic1 In-Reply-To: <3BE820A8.8B93A497@osdl.org> Message-ID: Organization: Technical University of Gdansk 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 On Tue, 6 Nov 2001, Randy.Dunlap wrote: > The Intel chipset specs say that PIC1 uses: > (all hex:) 20-21, 24-25, 28-29, 2c-2d, 30-31, 34-35, 38-39, 3c-3d. > > Some of the older chipset specs say that all of these other than > 20-21 are just aliases of 20-21 (like the 440MX spec). > Later specs don't say this (as in all of the 800-model ICH0/ICH2 > specs). These are chipset implementation details (i.e. address decoder's shortcomings) only. An 8259A only uses two I/O ports; in PC/AT systems, these are 0x20, 0x21 and 0xa0, 0xa1 for the two PICs, respectively. Since the 0x00-0xff range is assigned to motherboard devices, there is no problem with leaving aliases free -- they are never used by Linux. You still need to verify your extra devices are really present there. -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/