From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754045AbYI0Uy4 (ORCPT ); Sat, 27 Sep 2008 16:54:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752428AbYI0Uys (ORCPT ); Sat, 27 Sep 2008 16:54:48 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:48186 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752339AbYI0Uyr (ORCPT ); Sat, 27 Sep 2008 16:54:47 -0400 Date: Sat, 27 Sep 2008 22:53:57 +0200 From: Ingo Molnar To: Bjorn Helgaas Cc: Frans Pop , Rene Herman , linux-kernel@vger.kernel.org, Rene Herman , Thomas Gleixner , Jesse Barnes , Matthew Wilcox , Benjamin Herrenschmidt , "Rafael J. Wysocki" , bugme-daemon@bugzilla.kernel.org Subject: Re: [Bug #11550] pnp: Huge number of "io resource overlap" messages Message-ID: <20080927205357.GC31650@elte.hu> References: <200809091250.08620.elendil@planet.nl> <200809210149.07755.elendil@planet.nl> <200809201756.25157.bjorn.helgaas@hp.com> <200809261540.31443.bjorn.helgaas@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200809261540.31443.bjorn.helgaas@hp.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Bjorn Helgaas wrote: > The problem seems to be that Frans has some PCI devices that are not > configured by the BIOS, and their BARs contain zero. A PNP quirk > checks for overlaps of PCI devices and PNP devices, and those zero- > valued BARs of course conflict with the PNP motherboard devices that > describe legacy hardware. > > Here's another approach based on section 3.5 of the PCI Firmware spec. > It says: > > Since not all devices may be configured prior to the operating > system handoff, the operating system needs to know whether a > specific BAR register has been configured by firmware. The operating > system makes the determination by checking the I/O Enable, and > Memory Enable bits in the device's command register, and Expansion > ROM BAR enable bits. If the enable bit is set, then the corresponding > resource register has been configured. > > So instead of checking whether the BAR contains zero, the patch below > checks the I/O, Mem, and ROM BAR enable bits to determine whether a > BAR is enabled. cool! Looks like a pretty significant fix, for all sorts of legacy devices. Worth backporting? Ingo