From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932333Ab0I3Rjw (ORCPT ); Thu, 30 Sep 2010 13:39:52 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:38872 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932315Ab0I3Rjv (ORCPT ); Thu, 30 Sep 2010 13:39:51 -0400 Date: Thu, 30 Sep 2010 18:39:45 +0100 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-pci@vger.kernel.org, joerg.roedel@amd.com, jbarnes@virtuousgeek.org Subject: Re: [PATCH] pci: Reenable the AMD IOMMU if it's mysteriously vanished over suspend Message-ID: <20100930173945.GA16596@srcf.ucam.org> References: <1285861108-24122-1-git-send-email-mjg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1285861108-24122-1-git-send-email-mjg@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 30, 2010 at 11:38:28AM -0400, Matthew Garrett wrote: > AMD's reference BIOS code had a bug that could result in the firmware > failing to reenable the iommu on resume. It transpires that this causes > certain less than desirable behaviour when it comes to PCI accesses, to > whit them ending up somewhere near Bristol when the more desirable outcome > was Edinburgh. Sadness ensues, perhaps along with filesystem corruption. > Let's make sure that it gets turned back on. Of course, this isn't actually sufficient - nothing in the iommu code appears to reprogram the BAR, for instance. Joerg, how is this meant to work? -- Matthew Garrett | mjg59@srcf.ucam.org