From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932664AbXC0Vpk (ORCPT ); Tue, 27 Mar 2007 17:45:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932778AbXC0Vpk (ORCPT ); Tue, 27 Mar 2007 17:45:40 -0400 Received: from smtp.osdl.org ([65.172.181.24]:44191 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932664AbXC0Vpj (ORCPT ); Tue, 27 Mar 2007 17:45:39 -0400 Date: Tue, 27 Mar 2007 14:34:27 -0700 (PDT) From: Linus Torvalds To: Len Brown cc: Thomas Gleixner , Pavel Machek , Ingo Molnar , "Eric W. Biederman" , Nick Piggin , Mingming Cao , Adrian Bunk , Andrew Morton , Linux Kernel Mailing List , Michal Piotrowski , Mariusz Kozlowski , Oliver Pinter , Sid Boyce , Nick Piggin , Jens Axboe , Thomas Renninger Subject: Re: [PATCH] i386: add command line option "local_apic_timer_c2_ok" In-Reply-To: <200703271719.25795.lenb@kernel.org> Message-ID: References: <20070326123141.GA11288@ucw.cz> <1174917142.4182.39.camel@chaos> <200703271719.25795.lenb@kernel.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Mar 2007, Len Brown wrote: > > I think the only fool-proof way to do this automatically is to Why not just take the known-good CPUID signature? Screw firmware or ACPI tables. They're going to be occasionally wrong. If we know that "Core 2, version X" has a good local APIC timer, we use it. Otherwise we don't. That's generally how we handle other APIC bugs too (the read-after-write thing, for example, or the differences between integrated and off-chip APIC's). Sometimes we check the APIC version itself, sometimes we check the CPUID information, and sometimes we check both ("modern_apic()"). Linus