From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755508AbZEKOWt (ORCPT ); Mon, 11 May 2009 10:22:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751404AbZEKOWj (ORCPT ); Mon, 11 May 2009 10:22:39 -0400 Received: from www.tglx.de ([62.245.132.106]:39799 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751318AbZEKOWi (ORCPT ); Mon, 11 May 2009 10:22:38 -0400 Date: Mon, 11 May 2009 16:22:16 +0200 (CEST) From: Thomas Gleixner To: Frans Pop cc: linux-kernel@vger.kernel.org, Steven Rostedt , len.brown@intel.com, mingo@elte.hu, johnstul@us.ibm.com Subject: [PATCH] ACPI: do not mark TSC unstable for invalid C-states In-Reply-To: <200905110226.50115.elendil@planet.nl> Message-ID: References: <200905110226.50115.elendil@planet.nl> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit a71e4917dc0ebbcb5a0ecb7ca3486643c1c9a6e2 (ACPI: idle: mark_tsc_unstable() at init-time, not run-time) marks TSC unstable even on non affected systems. The reason is that the state enumeration does not check the cx->valid flag before calling tsc_halts_in_c(), so it marks TSC unstable for any enumerated albeit invalid C state which is known to turn off TSC. Check cx->valid before checking whether the TSC might become unstable. Signed-off-by: Thomas Gleixner --- drivers/acpi/processor_idle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6/drivers/acpi/processor_idle.c =================================================================== --- linux-2.6.orig/drivers/acpi/processor_idle.c +++ linux-2.6/drivers/acpi/processor_idle.c @@ -583,7 +583,7 @@ static int acpi_processor_power_verify(s #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86) /* TSC could halt in idle, so notify users */ - if (tsc_halts_in_c(cx->type)) + if (cx->valid && tsc_halts_in_c(cx->type)) mark_tsc_unstable("TSC halts in idle");; #endif switch (cx->type) {