From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752692Ab1G2SJX (ORCPT ); Fri, 29 Jul 2011 14:09:23 -0400 Received: from smtp-out.google.com ([74.125.121.67]:22724 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233Ab1G2SJW (ORCPT ); Fri, 29 Jul 2011 14:09:22 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=dkim-signature:mime-version:in-reply-to:references:from:date: message-id:subject:to:cc:content-type:x-system-of-record; b=MdjhUOxfol/n+uMUZ18zn4qzfx27K8vhgQxFmN7YdNdz78/sVrwVEvVOINJIicwtZ bR1zo0XboKJ0EhX+kxoaA== MIME-Version: 1.0 In-Reply-To: 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> From: Bjorn Helgaas Date: Fri, 29 Jul 2011 11:35:51 -0600 Message-ID: Subject: Re: [PATCH 1/2] PCI: make pci_claim_resource() work with conflict resources as appropriate To: Deng-Cheng Zhu Cc: Ralf Baechle , 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 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 29, 2011 at 12:32 AM, Deng-Cheng Zhu wrote: > 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). This seems like the real problem: PCI has the wrong idea of the resources available on bus 00. The pci_bus->resource[0] for bus 00 points to ioport_resource (the default put there by pci_create_bus()), when it should point to to msc_io_resource instead. Some architectures fill in the pci_bus->resource[] array directly for host bridges (for examples, try 'grep -r "resource\[0\] = " arch/'). On x86 and ia64, we use pci_bus_remove_resources() and pci_bus_add_resource(), and I'd prefer that style for new code because it hides some ugly implementation details. I'm a little puzzled that we don't see this problem on more architectures. The grep above only found a few arches that update the root bus resources. I would expect most of the ones it didn't find to be broken the same way Malta is. Bjorn