From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936AbYLWXfi (ORCPT ); Tue, 23 Dec 2008 18:35:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751267AbYLWXfa (ORCPT ); Tue, 23 Dec 2008 18:35:30 -0500 Received: from main.gmane.org ([80.91.229.2]:49716 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbYLWXf3 (ORCPT ); Tue, 23 Dec 2008 18:35:29 -0500 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Robert Hancock Subject: Re: [PATCH] pci-quirks: Unhide 'Overflow' device on i828{6,7}5P/PE chipsets Date: Tue, 23 Dec 2008 17:35:14 -0600 Message-ID: <495175B2.60307@shaw.ca> References: <20081223215030.GA32525@rere.qmqm.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@ger.gmane.org Cc: linux-pci@vger.kernel.org X-Gmane-NNTP-Posting-Host: s0106000c41bb86e1.ss.shawcable.net User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) In-Reply-To: <20081223215030.GA32525@rere.qmqm.pl> Cc: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michał Mirosław wrote: > As I found out from EDAC driver sources for i82875P some BIOSes for > i82875P/PE hide 'overflow' device 6. The same thing happens for > i82865P/PE chipsets. > > After testing this patch for couple of days on my laptop (i82856P) > it looks like something is resetting device 0 (MCH) config register > 0xF4 to zero and effectively disabling the device again. The delay > looks random to me. I can easily update the register using > 'hexedit /sys/bus/pci/devices/0000\:00\:00.0/config' and see > correct values in lspci output afterwards. Could be the BIOS is using the device in SMI code or something (and that's what disables it), therefore it may be unsafe to unhide this device.