Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754168Ab0GAHMX (ORCPT ); Thu, 1 Jul 2010 03:12:23 -0400 Received: from mga02.intel.com ([134.134.136.20]:41768 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753996Ab0GAHMW (ORCPT ); Thu, 1 Jul 2010 03:12:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,518,1272870000"; d="scan'208";a="635311751" Subject: Re: BUG in drivers/dma/ioat/dma_v2.c:314 From: David Woodhouse To: "Williams, Dan J" Cc: Chris Li , linux-kernel In-Reply-To: <4C2C3B07.7050200@intel.com> References: <4C29420D.2010406@intel.com> <4C2A8879.8010000@intel.com> <4C2AC55E.3040303@intel.com> <1277923422.16256.8.camel@localhost> <4C2B9DAC.1030806@intel.com> <1277928125.18854.0.camel@localhost> <4C2BBACF.3080405@intel.com> <1277965264.18854.16.camel@localhost> <4C2C3B07.7050200@intel.com> Content-Type: text/plain; charset="UTF-8" Organization: Intel Corporation Date: Thu, 01 Jul 2010 08:12:16 +0100 Message-ID: <1277968336.4945.3.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.31.4 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1805 Lines: 38 On Thu, 2010-07-01 at 07:51 +0100, Williams, Dan J wrote: > On 6/30/2010 11:21 PM, Woodhouse, David wrote: > > On Wed, 2010-06-30 at 22:44 +0100, Williams, Dan J wrote: > >> I don't see a way around this beyond blacklisting this (platform, vt-d > >> setting, driver) combination. Is there a quirk infrastructure for this > >> sort of problem? > > > > Yeah, kind of. If the IOAT PCI device _always_ has its own IOMMU, we > > could have a quirk for it which says it must _never_ be matched by a > > catch-all IOMMU. That would probably solve it? > > > > This version of the device only exists on the 5400 chipset and always > has its own iommu, but since other platforms get the DMAR entry right I > think this hammer is too big? Wouldn't this break VT-d operation on > non-busted platforms? That just means we have to get the quirk right. Does 'this version' of the device have its own PCI ID? We can always fall back to checking the ID of the device at 0000:00:00.0 to check which chipset we're on. > Alternatively I can just catch this failure earlier in the init process > and fail the driver load with a grumble printk about broken bios... > instead of the current BUG_ON() that is meant to catch runtime catastrophes. Please use WARN_TAINT(TAINT_FIRMWARE_WORKAROUND). That way the statistics end up in kerneloops.org and we have found that extremely useful when LARTing the offending vendors. -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/