From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757500Ab2GRAEh (ORCPT ); Tue, 17 Jul 2012 20:04:37 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:48754 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757374Ab2GRADu (ORCPT ); Tue, 17 Jul 2012 20:03:50 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Thomas Renninger , "Rafael J. Wysocki" Subject: [ 10/37] cpufreq / ACPI: Fix not loading acpi-cpufreq driver regression Date: Tue, 17 Jul 2012 17:02:47 -0700 Message-Id: <20120717232432.163237917@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120717232431.399005532@linuxfoundation.org> References: <20120717232455.GA5994@kroah.com> <20120717232431.399005532@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Renninger commit c4686c71a9183f76e3ef59098da5c098748672f6 upstream. Commit d640113fe80e45ebd4a5b420b introduced a regression on SMP systems where the processor core with ACPI id zero is disabled (typically should be the case because of hyperthreading). The regression got spread through stable kernels. On 3.0.X it got introduced via 3.0.18. Such platforms may be rare, but do exist. Look out for a disabled processor with acpi_id 0 in dmesg: ACPI: LAPIC (acpi_id[0x00] lapic_id[0x10] disabled) This problem has been observed on a: HP Proliant BL280c G6 blade This patch restricts the introduced workaround to platforms with nr_cpu_ids <= 1. Signed-off-by: Thomas Renninger Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/processor_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -189,10 +189,12 @@ int acpi_get_cpuid(acpi_handle handle, i * Processor (CPU3, 0x03, 0x00000410, 0x06) {} * } * - * Ignores apic_id and always return 0 for CPU0's handle. + * Ignores apic_id and always returns 0 for the processor + * handle with acpi id 0 if nr_cpu_ids is 1. + * This should be the case if SMP tables are not found. * Return -1 for other CPU's handle. */ - if (acpi_id == 0) + if (nr_cpu_ids <= 1 && acpi_id == 0) return acpi_id; else return apic_id;