From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755165Ab1G2GcJ (ORCPT ); Fri, 29 Jul 2011 02:32:09 -0400 Received: from mail-qy0-f174.google.com ([209.85.216.174]:43319 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754837Ab1G2GcH convert rfc822-to-8bit (ORCPT ); Fri, 29 Jul 2011 02:32:07 -0400 MIME-Version: 1.0 In-Reply-To: <20110728115330.GA29899@linux-mips.org> References: <1311852512-7340-1-git-send-email-dengcheng.zhu@gmail.com> <1311852512-7340-2-git-send-email-dengcheng.zhu@gmail.com> <20110728115330.GA29899@linux-mips.org> Date: Fri, 29 Jul 2011 14:32:06 +0800 Message-ID: Subject: Re: [PATCH 1/2] PCI: make pci_claim_resource() work with conflict resources as appropriate From: Deng-Cheng Zhu To: Ralf Baechle Cc: jbarnes@virtuousgeek.org, torvalds@linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, eyal@mips.com, zenon@mips.com 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 I noticed that at 79896cf42f Linus changed the function from insert_resource() to request_resource() (and later evolved into request_resource_conflict()) and he explained the reason. So, in the NIC's case, the problem is that in pci_claim_resource() the function pci_find_parent_resource() returns the root (0x0-0xffffff) rather than the MSC PCI I/O (0x1000-0xffffff). So request_resource_conflict() for PCI quirks (0x1000-0x103f and 0x1100-0x110f) will simply return an error, coz these 2 regions 'conflict' with MSC PCI I/O. Instead, insert_resource_conflict() will also find the collisions but register quirks as children of MSC PCI I/O (is this supposed to be correct?) and return a success. Deng-Cheng 2011/7/28 Ralf Baechle > > On Thu, Jul 28, 2011 at 07:28:31PM +0800, Deng-Cheng Zhu wrote: > > > In resolving a network driver issue with the MIPS Malta platform, the root > > cause was traced into pci_claim_resource(): > > > > MIPS System Controller's PCI I/O resources stay in 0x1000-0xffffff. When > > PCI quirks start claiming resources using request_resource_conflict(), > > collisions happen and -EBUSY is returned, thereby rendering the onboard AMD > > PCnet32 NIC unaware of quirks' region and preventing the NIC from functioning. > > For PCI quirks, PIIX4 ACPI is expected to claim 0x1000-0x103f, and PIIX4 SMB to > > claim 0x1100-0x110f, both of which fall into the MSC I/O range. Certainly, we > > can increase the start point of this range in arch/mips/mti-malta/malta-pci.c to > > avoid the collisions. But a fix in here looks more justified, though it seems to > > have a wider impact. Using insert_xxx as opposed to request_xxx will register > > PCI quirks' resources as children of MSC I/O and return OK, instead of seeing > > collisions which are actually resolvable. > > This used to work in the past; do you know which commit broke the resource > handling for the NIC? > >  Ralf