From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754878AbYDUUpo (ORCPT ); Mon, 21 Apr 2008 16:45:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752328AbYDUUpg (ORCPT ); Mon, 21 Apr 2008 16:45:36 -0400 Received: from outbound-mail-116.bluehost.com ([69.89.22.16]:41207 "HELO outbound-mail-116.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751925AbYDUUpg convert rfc822-to-8bit (ORCPT ); Mon, 21 Apr 2008 16:45:36 -0400 From: Jesse Barnes To: Jean Delvare Subject: Re: PCI MSI breaks when booting with nosmp Date: Mon, 21 Apr 2008 13:40:20 -0700 User-Agent: KMail/1.9.9 Cc: Andi Kleen , linux-pci@atrey.karlin.mff.cuni.cz, LKML , Pavel Machek , Tejun Heo , Tom Long Nguyen , Randy Dunlap , Jeff Garzik References: <200804172140.02311.jdelvare@suse.de> <87d4oj6o9a.fsf@basil.nowhere.org> <200804212220.20577.jdelvare@suse.de> In-Reply-To: <200804212220.20577.jdelvare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200804211340.21713.jbarnes@virtuousgeek.org> X-Identified-User: {642:box128.bluehost.com:virtuous:virtuousgeek.org} {sentby:smtp auth 75.111.27.49 authed with jbarnes@virtuousgeek.org} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, April 21, 2008 1:20 pm Jean Delvare wrote: > Hi Andi, > > Le lundi 21 avril 2008, Andi Kleen a écrit : > > Jesse Barnes writes: > > > Ok, I see this too on my desktop machine. It looks like we're not > > > getting interrupts setup correctly in the nosmp case. Still digging > > > through to see why though... > > > > NoSMP disables the io-apic and a lot of modern systems don't work without > > APIC. > > > > If you just want to run with a single cpu for testing etc. always use > > maxcpus=1 (not 0, that will disable the APIC too) > > In my case, booting with noapic works fine, so I don't think that the > problem is related to APIC being disabled. One difference between noapic and nosmp is that in the nosmp case even the local APIC setup won't occur in native_smp_prepare_cpus(), due to smp_sanity_check() returning -1 in the setup_max_cpus == 0 case. So we either need smp_sanity_check to do a little more APIC setup if max_cpus == 0 or shuffle things around in native_smp_prepare_cpus(). Since the former is already done for 32 bit builds for the NMI vector, maybe we should just make it unconditional so that MSI works? Jesse