Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161746Ab1FAINO (ORCPT ); Wed, 1 Jun 2011 04:13:14 -0400 Received: from cantor2.suse.de ([195.135.220.15]:43069 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161718Ab1FAINJ (ORCPT ); Wed, 1 Jun 2011 04:13:09 -0400 X-Mailbox-Line: From linux@blue.kroah.org Wed Jun 1 17:03:41 2011 Message-Id: <20110601080340.618449914@blue.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 01 Jun 2011 17:00:13 +0900 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Boris Ostrovsky , Hans Rosenfeld , Andreas Herrmann , Chuck Ebbert , "H. Peter Anvin" , Greg Kroah-Hartman Subject: [077/146] x86, amd: Do not enable ARAT feature on AMD processors below In-Reply-To: <20110601080606.GA522@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1993 Lines: 57 2.6.38-stable review patch. If anyone has any objections, please let us know. ------------------ family 0x12 From: Boris Ostrovsky commit e9cdd343a5e42c43bcda01e609fa23089e026470 upstream. Commit b87cf80af3ba4b4c008b4face3c68d604e1715c6 added support for ARAT (Always Running APIC timer) on AMD processors that are not affected by erratum 400. This erratum is present on certain processor families and prevents APIC timer from waking up the CPU when it is in a deep C state, including C1E state. Determining whether a processor is affected by this erratum may have some corner cases and handling these cases is somewhat complicated. In the interest of simplicity we won't claim ARAT support on processor families below 0x12 and will go back to broadcasting timer when going idle. Signed-off-by: Boris Ostrovsky Link: http://lkml.kernel.org/r/1306423192-19774-1-git-send-email-ostr@amd64.org Tested-by: Boris Petkov Cc: Hans Rosenfeld Cc: Andreas Herrmann Cc: Chuck Ebbert Signed-off-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -595,8 +595,11 @@ static void __cpuinit init_amd(struct cp } #endif - /* As a rule processors have APIC timer running in deep C states */ - if (c->x86 > 0xf && !cpu_has_amd_erratum(amd_erratum_400)) + /* + * Family 0x12 and above processors have APIC timer + * running in deep C states. + */ + if (c->x86 > 0x11) set_cpu_cap(c, X86_FEATURE_ARAT); /* -- 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/