Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764888Ab3DDUdy (ORCPT ); Thu, 4 Apr 2013 16:33:54 -0400 Received: from mail-oa0-f43.google.com ([209.85.219.43]:36743 "EHLO mail-oa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764835Ab3DDUdw (ORCPT ); Thu, 4 Apr 2013 16:33:52 -0400 MIME-Version: 1.0 In-Reply-To: <20130404200455.GB19354@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> From: Bjorn Helgaas Date: Thu, 4 Apr 2013 14:33:31 -0600 Message-ID: Subject: Re: [PATCH v4] irq: add quirk for broken interrupt remapping on 55XX chipsets To: Neil Horman Cc: Yinghai Lu , Don Dutile , Linux Kernel Mailing List , Prarit Bhargava , Don Zickus , Asit Mallick , David Woodhouse , "linux-pci@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1776 Lines: 38 On Thu, Apr 4, 2013 at 2:04 PM, Neil Horman wrote: > On Thu, Apr 04, 2013 at 10:40:07AM -0700, Yinghai Lu wrote: >> On Thu, Apr 4, 2013 at 10:27 AM, Don Dutile wrote: >> >> You need to move the quirk to early_quirk to append nointremap to >> >> avoid extra rebooting. >> >> >> > The pci-dev's of all the (minimally, root, 5500-chipset) pci-dev's are >> > known/scanned/created by that time? >> >> in arch/x86/kernel/early-quirk.c >> >> and on top of >> https://git.kernel.org/cgit/linux/kernel/git/yinghai/linux-yinghai.git/commit/?h=for-x86-early-quirk-usb&id=de38757e964cfee20e6da1977572a2191d7f4aa0 >> >> You could add one entry in early_qrk[]. >> >> Some one already try to use that path to disable x2apic on some thinkpad. >> >> So it should work on nointrremap too. >> > 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. Bjorn -- 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/