Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753996AbcKIN4n (ORCPT ); Wed, 9 Nov 2016 08:56:43 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:34552 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802AbcKIN4l (ORCPT ); Wed, 9 Nov 2016 08:56:41 -0500 Date: Wed, 9 Nov 2016 13:54:53 +0000 From: One Thousand Gnomes To: Arnd Bergmann Cc: Mark Rutland , "zhichang.yuan" , catalin.marinas@arm.com, will.deacon@arm.com, robh+dt@kernel.org, bhelgaas@google.com, olof@lixom.net, linux-arm-kernel@lists.infradead.org, lorenzo.pieralisi@arm.com, linux-kernel@vger.kernel.org, linuxarm@huawei.com, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, linux-serial@vger.kernel.org, minyard@acm.org, benh@kernel.crashing.org, liviu.dudau@arm.com, zourongrong@gmail.com, john.garry@huawei.com, gabriele.paoloni@huawei.com, zhichang.yuan02@gmail.com, kantyzc@163.com, xuwei5@hisilicon.com, marc.zyngier@arm.com Subject: Re: [PATCH V5 2/3] ARM64 LPC: Add missing range exception for special ISA Message-ID: <20161109135453.2e5402bd@lxorguk.ukuu.org.uk> In-Reply-To: <2368890.jTbyGqYR0M@wuerfel> References: <1478576829-112707-1-git-send-email-yuanzhichang@hisilicon.com> <1478576829-112707-3-git-send-email-yuanzhichang@hisilicon.com> <20161108114953.GB15297@leverpostej> <2368890.jTbyGqYR0M@wuerfel> Organization: Intel Corporation X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 694 Lines: 16 > I think it is a relatively safe assumption that there is only one > ISA bridge. A lot of old drivers hardcode PIO or memory addresses It's not a safe assumption for x86 at least. There are a few systems with multiple ISA busses particularly older laptops with a docking station. > when talking to an ISA device, so having multiple instances is > already problematic. PCMCIA devices handle it themselves so are ok. I'm not clear how the dual PIIX4 configuration used in the older IBM laptop docks actually worked so I assume the transaction went out of both bridges and providing one of them responded the other kept silent as you simply stuffed the card into the dock and it worked. Alan