Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932463Ab1EZPU7 (ORCPT ); Thu, 26 May 2011 11:20:59 -0400 Received: from s15228384.onlinehome-server.info ([87.106.30.177]:55447 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753203Ab1EZPU6 (ORCPT ); Thu, 26 May 2011 11:20:58 -0400 From: Boris Ostrovsky To: hpa@zytor.com, mingo@elte.hu, tglx@linutronix.de Cc: borislav.petkov@amd.com, Hans.Rosenfeld@amd.com, Andreas.Herrmann3@amd.com, cebbert@redhat.com, Boris.Ostrovsky@amd.com, linux-kernel@vger.kernel.org, jvpeetz@web.de, stable@kernel.org, x86@kernel.org Subject: [PATCH RESEND] x86, AMD: Do not enable ARAT feature on AMD processors below family 0x12 Date: Thu, 26 May 2011 11:19:52 -0400 Message-Id: <1306423192-19774-1-git-send-email-ostr@amd64.org> X-Mailer: git-send-email 1.7.5.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1760 Lines: 48 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 Tested-by: Boris Petkov Cc: Hans Rosenfeld Cc: Andreas Herrmann Cc: Chuck Ebbert Cc: stable@kernel.org # 32.x, 38.x, 39.x --- arch/x86/kernel/cpu/amd.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 6f9d1f6..728b223 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -612,8 +612,11 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) } #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); /* -- 1.7.3.4 -- 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/