Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754274AbcKNLMQ (ORCPT ); Mon, 14 Nov 2016 06:12:16 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:32844 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087AbcKNLMO (ORCPT ); Mon, 14 Nov 2016 06:12:14 -0500 Date: Mon, 14 Nov 2016 11:11:11 +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: <20161114111111.1b753dc3@lxorguk.ukuu.org.uk> In-Reply-To: <5900275.i4NZvtxTcC@wuerfel> References: <1478576829-112707-1-git-send-email-yuanzhichang@hisilicon.com> <2368890.jTbyGqYR0M@wuerfel> <20161109135453.2e5402bd@lxorguk.ukuu.org.uk> <5900275.i4NZvtxTcC@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: 823 Lines: 19 > > 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. > > But do they have multiple ISA domains? There is no real harm in supporting > it, the (small) downsides I can think of are: I don't believe they x86 class ones have multiple ISA domains. But as I've said I don't know how the electronics in the older ThinkPad worked when it used two PIIX4s with some LPC or ISA stuff on each. It works in DOS and unmodified Linux so I'm pretty sure there are no additional domains. Likewise the various x86 schemes that route some bits of ISA bus off into strange places work in DOS and don't have any overlaps. yenta_socket handles PCI/PCMCIA bridging and routes a range of that flat ISA space appropriately to the card. Alan