Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765679Ab3DEAYk (ORCPT ); Thu, 4 Apr 2013 20:24:40 -0400 Received: from charlotte.tuxdriver.com ([70.61.120.58]:34736 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765169Ab3DEAYi (ORCPT ); Thu, 4 Apr 2013 20:24:38 -0400 Date: Thu, 4 Apr 2013 20:24:05 -0400 From: Neil Horman To: Yinghai Lu Cc: Bjorn Helgaas , Don Dutile , Linux Kernel Mailing List , Prarit Bhargava , Don Zickus , Asit Mallick , David Woodhouse , "linux-pci@vger.kernel.org" Subject: Re: [PATCH v4] irq: add quirk for broken interrupt remapping on 55XX chipsets Message-ID: <20130405002405.GA24109@hmsreliant.think-freely.org> References: <1362158276-4901-1-git-send-email-nhorman@tuxdriver.com> <1365088091-10862-1-git-send-email-nhorman@tuxdriver.com> <515DB7F6.8010502@redhat.com> <20130404200455.GB19354@hmsreliant.think-freely.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: -2.9 (--) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1804 Lines: 40 On Thu, Apr 04, 2013 at 02:11:54PM -0700, Yinghai Lu wrote: > On Thu, Apr 4, 2013 at 1:33 PM, Bjorn Helgaas wrote: > >> See my last email to Bjorn. Doing this in early-quirks in such a way that we > >> can detect an iommu that has interrupt remapping enabled (so we don't just > >> unilaterally print this quirk all the time) requires that we be able to parse > >> acpi tables very early in the boot. If you know of how to do that, I can make > >> this happen. If not, I suppose another alternative would be to have the early > >> quirk set a flag that tells us this is a bogus chip, and if we try to enable irq > >> remapping with that flag set, we should fail, and report the error at that time, > >> but I'm not sure I like that solution. > > > > I like that solution :) It seems very simple -- you don't have to > > parse any tables or anything. > > You are right, we don't need to parse any acpi tables. > > just add one quirk in early-quirk.c to set > disable_irq_remap = 1; > Well, I can't just do that. We need to issue a warning to the user as well, and to do so conditionally (we don't want to warn users who have prorperly updated BIOSes), I would need to know if irq remapping is actually on or not, which would require parsing ACPI tables But, as noted above, I can just set a flag, and defer the printing of the warning until later in the boot process, when we know that information already. Bjorn seems on board with that idea, so I'll spin up a patch for it in the AM. Thanks! Neil > Thanks > > Yinghai > -- 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/