From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Re: [PATCH 1/1] x86 TSC: set X86_FEATURE_TSC_RELIABLE, per CPUID Date: Mon, 01 Jun 2015 11:40:04 -0700 Message-ID: <556CA704.1070000@kernel.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.kernel.org ([198.145.29.136]:32865 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753909AbbFASkL (ORCPT ); Mon, 1 Jun 2015 14:40:11 -0400 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Len Brown , x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Len Brown On 05/30/2015 10:44 PM, Len Brown wrote: > From: Len Brown > > Speed cpu_up() by believing CPUID's "invariant TSC" flag, > and skipping the TSC warp test on single socket systems. I'm typing this email on a "Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz" with a "X79A-GD65 (8D) (MS-7760)" motherboard. (DO NOT BUY THAT MOTHERBOARD!) The brilliant stock firmware breaks TSC sync on bootup. Even with the updated firmware I'm using, it's broken on resume from S3. If you want to make this depend on X86_FEATURE_TSC_ADJUST and confirm that all cores have the same IA32_TSC_ADJUST value, then maybe that would be okay. Otherwise, please don't underestimate the malice^Wgross incompetence of firmware vendors. --Andy