Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757703AbYJXSSy (ORCPT ); Fri, 24 Oct 2008 14:18:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750951AbYJXSSn (ORCPT ); Fri, 24 Oct 2008 14:18:43 -0400 Received: from mx2.redhat.com ([66.187.237.31]:34638 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753908AbYJXSSm (ORCPT ); Fri, 24 Oct 2008 14:18:42 -0400 Message-ID: <4902116B.50509@redhat.com> Date: Fri, 24 Oct 2008 14:18:19 -0400 From: Chris Snook User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Scott Wood CC: Kumar Gala , LinuxPPC-dev list , tglx@linutronix.de, linux-kernel Kernel , maxk@qualcomm.com Subject: Re: default IRQ affinity change in v2.6.27 (breaking several SMP PPC based systems) References: <4E3CD4D5-FC1B-40BF-A776-C612B95806B8@kernel.crashing.org> <4901E6FB.4070200@redhat.com> <36A821E7-7F37-42AF-9A05-7205FCBF89EE@kernel.crashing.org> <4901F31E.9040007@redhat.com> <5967704E-0117-46B8-8505-6A002502C38C@kernel.crashing.org> <4902086E.6030900@freescale.com> In-Reply-To: <4902086E.6030900@freescale.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1222 Lines: 34 Scott Wood wrote: > Kumar Gala wrote: >> So why not just have x86 startup code set irq_default_affinity = >> CPU_MASK_ALL than? > > That doesn't really solve the problem, as a user could still manually > set an invalid affinity. The MPIC driver should reduce the affinity > itself to what the hardware can handle. Does the MPIC code actually allow that to happen? I can't quite tell, but I noticed this: [csnook@bernoulli sysdev]$ fgrep '#ifdef CONFIG_' mpic.c | sort -u #ifdef CONFIG_IRQ_ALL_CPUS #ifdef CONFIG_MPIC_BROKEN_REGREAD #ifdef CONFIG_MPIC_U3_HT_IRQS #ifdef CONFIG_MPIC_WEIRD #ifdef CONFIG_PCI_MSI #ifdef CONFIG_PM #ifdef CONFIG_PPC32 /* XXX for now */ #ifdef CONFIG_PPC_DCR #ifdef CONFIG_SMP Do any of those config options (or combinations thereof) imply an MPIC that can't handle an IRQ masked to multiple CPUs? If so, this can be fixed rather easily at build time, without having to muck around with arch-specific initialization code. -- Chris -- 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/