Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762182Ab3DBTcp (ORCPT ); Tue, 2 Apr 2013 15:32:45 -0400 Received: from mail.skyhub.de ([78.46.96.112]:42008 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761551Ab3DBTcn (ORCPT ); Tue, 2 Apr 2013 15:32:43 -0400 Date: Tue, 2 Apr 2013 21:32:40 +0200 From: Borislav Petkov To: Joerg Roedel Cc: suravee.suthikulpanit@amd.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] iommu/amd: Add logic to decode AMD IOMMU event flag Message-ID: <20130402193240.GF17675@pd.tnic> Mail-Followup-To: Borislav Petkov , Joerg Roedel , suravee.suthikulpanit@amd.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <1364428283-2548-1-git-send-email-suravee.suthikulpanit@amd.com> <20130402143335.GB15687@8bytes.org> <20130402144037.GE5488@pd.tnic> <20130402150302.GF15687@8bytes.org> <20130402152956.GE4391@pd.tnic> <20130402160400.GP30540@8bytes.org> <20130402161757.GC17519@pd.tnic> <20130402163318.GS30540@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20130402163318.GS30540@8bytes.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1676 Lines: 40 On Tue, Apr 02, 2013 at 06:33:18PM +0200, Joerg Roedel wrote: > I can't find out in the driver whether the fix works or not. It will > be noticed later when the x86 code tries to setup the timers and finds > out that they don't work, which causes a kernel panic. > > Okay, in theory I could implement a feedback loop between timer-setup > and intremap code and try fixups until it works. But that seems not to > be worth it to work around a buggy BIOS. Yeah, same here. It's not like we really need intremap to work - we're only trying to fix the annoying error message currently. :-) > What I actually thought about was providing an IVRS-override on the > kernel command line. So that you can specify the IOAPIC_ID->DEVID > mapping there and make it work this way. What do you think? I guess that is workable. I can imagine people wanting this if they want to do the intremap thing on such b0rked BIOSen. So how do I specify this IOAPIC_ID->DEVID mapping on the cmdline exactly? > > And yes, I'm very sceptical about having a WARN_ON and it starts > > screaming on machines all over the place. Good luck explaining to > > people that you actually wanted to prod BIOS vendors to fix their > > monkey-on-crack code but they weren't listening in the first place. > > Yeah, that's my fear too. So we leave it better as it is... Hohumm. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- 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/