From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262308AbVAJQKT (ORCPT ); Mon, 10 Jan 2005 11:10:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262310AbVAJQKT (ORCPT ); Mon, 10 Jan 2005 11:10:19 -0500 Received: from one.firstfloor.org ([213.235.205.2]:53951 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262308AbVAJQKO (ORCPT ); Mon, 10 Jan 2005 11:10:14 -0500 To: brking@us.ibm.com Cc: paulus@samba.org, benh@kernel.crashing.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] pci: Block config access during BIST (resend) References: <200501101449.j0AEnWYF020850@d03av01.boulder.ibm.com> From: Andi Kleen Date: Mon, 10 Jan 2005 17:10:12 +0100 In-Reply-To: <200501101449.j0AEnWYF020850@d03av01.boulder.ibm.com> (brking@us.ibm.com's message of "Mon, 10 Jan 2005 08:49:31 -0600") Message-ID: User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org brking@us.ibm.com writes: > Some PCI adapters (eg. ipr scsi adapters) have an exposure today in that > they issue BIST to the adapter to reset the card. If, during the time > it takes to complete BIST, userspace attempts to access PCI config space, > the host bus bridge will master abort the access since the ipr adapter > does not respond on the PCI bus for a brief period of time when running BIST. > On PPC64 hardware, this master abort results in the host PCI bridge > isolating that PCI device from the rest of the system, making the device > unusable until Linux is rebooted. This patch is an attempt to close that > exposure by introducing some blocking code in the PCI code. When blocked, > writes will be humored and reads will return the cached value. Ben > Herrenschmidt has also mentioned that he plans to use this in PPC power > management. I think it would be better to do this check higher level in the driver. IMHO pci_*_config should stay lean and fast low level functions without such baggage. -Andi