Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932509AbWBXBtJ (ORCPT ); Thu, 23 Feb 2006 20:49:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932504AbWBXBtI (ORCPT ); Thu, 23 Feb 2006 20:49:08 -0500 Received: from dsl093-040-174.pdx1.dsl.speakeasy.net ([66.93.40.174]:43416 "EHLO aria.kroah.org") by vger.kernel.org with ESMTP id S932509AbWBXBtH (ORCPT ); Thu, 23 Feb 2006 20:49:07 -0500 Date: Thu, 23 Feb 2006 17:47:55 -0800 From: Greg KH To: Andrew Morton , kristen.c.accardi@intel.com Cc: Bernhard Kaindl , linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, Alan Cox , Ivan Kokshaysky Subject: Re: [PATCH] PCI/Cardbus cards hidden, needs pci=assign-busses to fix Message-ID: <20060224014755.GD25787@kroah.com> References: <1136555288.30498.12.camel@localhost.localdomain> <20060218014102.0647c0ce.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060218014102.0647c0ce.akpm@osdl.org> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2062 Lines: 48 On Sat, Feb 18, 2006 at 01:41:02AM -0800, Andrew Morton wrote: > Bernhard Kaindl wrote: > > > > "In some cases, especially on modern laptops with a lot of PCI and cardbus > > bridges, we're unable to assign correct secondary/subordinate bus numbers > > to all cardbus bridges due to BIOS limitations unless we are using > > "pci=assign-busses" boot option." -- Ivan Kokshaysky (from a patch comment) > > > > Without it, Cardbus cards inserted are never seen by PCI because the > > parent PCI-PCI Bridge of the Cardbus bridge will not pass and translate > > Type 1 PCI configuration cycles correctly and the system will fail to > > find and initialise the PCI devices in the system. > > > > Reference: PCI-PCI Bridges: PCI Configuration Cycles and PCI Bus Numbering: > > http://www.science.unitn.it/~fiorella/guidelinux/tlk/node72.html > > > > The reason for this is that: > > ``All PCI busses located behind a PCI-PCI bridge must reside between the > > secondary bus number and the subordinate bus number (inclusive).'' > > > > "pci=assign-busses" makes pcibios_assign_all_busses return 1 and this > > turns on PCI renumbering during PCI probing. > > > > Alan suggested to use DMI to make that function cause that on problem systems: > > > > [ snip patch which uses a DMI table to auto-set "pci=assign-busses" ] > > > > I guess if this is the only way in which we can do this, and nobody has any > better solutions then sure, it'll get people's machines going. We'll be > forever patching that table though. > > But _does_ anyone have any better solutions? This patch might not be needed at all, as per Kristen's recent comments on the linux-pci mailing list, and her small patch that is already in the -mm tree. I'll let the discussion continue on that list. thanks, greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/