From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932258AbWDLROk (ORCPT ); Wed, 12 Apr 2006 13:14:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932259AbWDLROk (ORCPT ); Wed, 12 Apr 2006 13:14:40 -0400 Received: from detroit.securenet-server.net ([209.51.153.26]:36515 "EHLO detroit.securenet-server.net") by vger.kernel.org with ESMTP id S932258AbWDLROj (ORCPT ); Wed, 12 Apr 2006 13:14:39 -0400 From: Jesse Barnes To: Ian Romanick Subject: Re: Special handling of sysfs device resource files? Date: Wed, 12 Apr 2006 10:14:35 -0700 User-Agent: KMail/1.9.1 Cc: lkml References: <443C1ECA.1040308@us.ibm.com> <443C42EA.1050608@us.ibm.com> In-Reply-To: <443C42EA.1050608@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604121014.35765.jbarnes@virtuousgeek.org> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - detroit.securenet-server.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - virtuousgeek.org X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, April 11, 2006 4:59 pm, Ian Romanick wrote: > Ian Romanick wrote: > > I'm in the process of modifying X to be civilized in it's handling > > of PCI devices on Linux. As part of that, I've modified it to map > > the /sys/bus/pci/device/*/resource[0-6] files instead of mucking > > about with /dev/mem. > > > > This seems to mostly work, but I am having one problem. I map the > > region by opening the file with O_RDWR, then mmap with > > (PROT_READ|PROT_WRITE) and MAP_SHARED. In all cases, the open and > > mmap succeed. However, for I/O BARs, the resulting pointer from > > mmap is invalid. Any access to it results in a segfault and GDB > > says it's "out of range". > > I was a little mistaken about this. The BAR that causes the problem > is not I/O. It *is* memory. > > 01:00.0 VGA compatible controller: Matrox Graphics, Inc. G400/G450 > (rev 03) (prog-if 00 [VGA]) > Subsystem: Matrox Graphics, Inc. Millennium G400 16Mb SGRAM > Flags: bus master, medium devsel, latency 64, IRQ 11 > Memory at cc000000 (32-bit, prefetchable) [size=32M] > Memory at cfefc000 (32-bit, non-prefetchable) [size=16K] > Memory at cf000000 (32-bit, non-prefetchable) [size=8M] > Expansion ROM at cfee0000 [disabled] [size=64K] > > When I open and mmap resource0 (the framebuffer) I get 0x2b9aa48ea000. > When I open and mmap resource1 (the card's registers) I get > 0x2b9aa68ea000. I can access the resource0 pointer all day long > without problems. The firs access to the resource1 pointer results in > a segfault. Hm, that's strange. On my via machine I can access all my VGA resources correctly, but that's not x86-64. Maybe the x86-64 implementation of pci_mmap_page_range is doing the wrong thing for uncacheable, non-WC regions somehow? Jesse