From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759143AbZBFTfk (ORCPT ); Fri, 6 Feb 2009 14:35:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753860AbZBFTfc (ORCPT ); Fri, 6 Feb 2009 14:35:32 -0500 Received: from hera.kernel.org ([140.211.167.34]:36535 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752380AbZBFTfb (ORCPT ); Fri, 6 Feb 2009 14:35:31 -0500 Message-ID: <498C90D5.9030400@kernel.org> Date: Fri, 06 Feb 2009 11:34:45 -0800 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Randy Dunlap CC: Ben Greear , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , "Maciej W. Rozycki" , linux-kernel , len.brown@intel.com Subject: Re: PATCH: (v2) Allow over-ride of smp_found_cfg with kernel cmd-line option. References: <498B421D.9090609@candelatech.com> <20090205195832.GD3129@elte.hu> <498C8DB7.3000005@candelatech.com> <498C8FE8.8090608@oracle.com> In-Reply-To: <498C8FE8.8090608@oracle.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Randy Dunlap wrote: > Ben Greear wrote: >> Ingo Molnar wrote: >>> * Ben Greear wrote: >>> >>>> Allow user to keep smp_found_cfg set to 1 even if MADT >>>> cannot be parsed. This works around funky BIOS on FWA-7304 >>>> (VIA CN700 chipset) system, and possibly other systems as well. >>>> Without this override, performance drops by around 15% on >>>> network throughput tests on this system. >>> I'd _much_ rather have a warning message printed and have a default, >>> unconditional fallback to mptable parsing in this case. >>> >>> I.e. same end result just no ugly and inconvenient force_smp_found_cfg. >>> >>> The mptable works fine in most such cases to enumerate apic details. >>> (as it does in your case, evidently) >>> >>> And if both the ACPI and the MPTABLE is hosed on a box, it cannot be >>> of much use on other OSs either, right? >>> >>> So please do a patch that removes the 'smp_found_config' and which >>> changes the warning message to warn about no ACPI table in the MADT >>> table. Ok? >> An updated patch is attached. It's also inline below, but I'm sure the >> inline version is white-space corrupted. >> >> Do not disable mptable parsing just because there is no ACPI table >> in the MADT table. This effectively backs out changeset >> 7b37b5fd9ba32c0c5afc3537eed7e7466f2173e2 >> >> Signed-Off-By: Ben Greear >> >> Thanks, >> Ben >> >> >> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c >> index d37593c..74a50b6 100644 >> --- a/arch/x86/kernel/acpi/boot.c >> +++ b/arch/x86/kernel/acpi/boot.c >> @@ -1379,12 +1379,14 @@ static void __init acpi_process_madt(void) >> * ACPI found no MADT, and so ACPI wants UP PIC mode. >> * In the event an MPS table was found, forget it. >> * Boot with "acpi=off" to use MPS on such a system. >> + * >> + * NOTE: This assumption seems wrong in at least some cases, >> perhaps >> + * when ACPI is off in the BIOS. Changing to a warning without >> + * setting smp_found_config to zero. >> */ >> - if (smp_found_config) { >> + if (smp_found_config) >> printk(KERN_WARNING PREFIX >> - "No APIC-table, disabling MPS\n"); >> - smp_found_config = 0; >> - } >> + "WARNING: No ACPI-table found in the MADT\n"); > > APIC table > APIC-table == MADT could just use WARNING: No APIC-table found YH