From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965747AbeCAD25 convert rfc822-to-8bit (ORCPT ); Wed, 28 Feb 2018 22:28:57 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:55280 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965657AbeCAD2z (ORCPT ); Wed, 28 Feb 2018 22:28:55 -0500 Date: Wed, 28 Feb 2018 22:28:53 -0500 (EST) Message-Id: <20180228.222853.1570972177848923005.davem@davemloft.net> To: helgaas@kernel.org Cc: dwmw2@infradead.org, sparclinux@vger.kernel.org, bhelgaas@google.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] sparc: Use generic pci_mmap_resource_range() From: David Miller In-Reply-To: <20180228230828.GR127842@bhelgaas-glaptop.roam.corp.google.com> References: <1519053858.7876.84.camel@infradead.org> <20180219.103025.1676484157305869188.davem@davemloft.net> <20180228230828.GR127842@bhelgaas-glaptop.roam.corp.google.com> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bjorn Helgaas Date: Wed, 28 Feb 2018 17:08:29 -0600 > On Mon, Feb 19, 2018 at 10:30:25AM -0500, David Miller wrote: >> From: David Woodhouse >> Date: Mon, 19 Feb 2018 15:24:18 +0000 >> >> >> For one, the sparc specific code allows mmap'ing any address range >> >> within a PCI bus device.  The generic code does not allow that. >> > >> > >> > You mean any address range in a given PCI bus even if there is no >> > actual device with a BAR at the corresponding address? >> > >> > Would I be right to assume this was only available through the legacy >> > procfs API? I think it should be possible to accommodate it, and it >> > does look like I'd missed this requirement the first time round; thanks >> > for pointing it out. >> >> It was probably the case that only procfs could do it. >> >> It is the mechanism by which we were able to let the X server poke >> around in VGA ISA space. It does a bus I/O space map for the bus >> device above the VGA card. > > What's the bottom line? Do we want this for sparc? If so, do you > want to take it, Dave M, or would you like me to? The bottom line is that David W.'s patch would break sparc so we don't want this.