From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161264AbXCNUro (ORCPT ); Wed, 14 Mar 2007 16:47:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161338AbXCNUro (ORCPT ); Wed, 14 Mar 2007 16:47:44 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44540 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161264AbXCNUrm (ORCPT ); Wed, 14 Mar 2007 16:47:42 -0400 To: Tejun Heo Cc: gregkh@suse.de, Jeff Garzik , linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, michal.k.k.piotrowski@gmail.com, linux-ide@vger.kernel.org, tglx@linutronix.de, shemminger@linux-foundation.org, mlord@pobox.com, linux-pm@lists.osdl.org Subject: Re: [PATCH/RFC] PCI prepare/activate instead of enable to avoid IRQ storm and rogue DMA access References: <20070314152302.GB15600@htj.dyndns.org> From: Andi Kleen Date: 14 Mar 2007 22:46:47 +0100 In-Reply-To: <20070314152302.GB15600@htj.dyndns.org> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 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 Tejun Heo writes: > > Let's assume there's a device which shares its INTX IRQ line with > another device and the other one is already initialized. During boot, > due to BIOS's fault, bad hardware design or sheer bad luck, the device > has got a pending IRQ. This seems to be also common after kexec during kexec crashdumps where the device just continues doing what it did before the crash. > This patch expands the pci_set_master() approach. Instead of enabling > the device in one go, it's done in two steps - prepare and activate. > 'prepare' enables access to PCI configuration, I hope there aren't any new erratas triggered by this. Perhaps it would make sense to add some paranoia sleeps at least before touching other state? -Andi