Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933187Ab1CaGNJ (ORCPT ); Thu, 31 Mar 2011 02:13:09 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:45396 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024Ab1CaGNH (ORCPT ); Thu, 31 Mar 2011 02:13:07 -0400 Date: Thu, 31 Mar 2011 08:12:47 +0200 From: Ingo Molnar To: Len Brown Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, Len Brown , Linus Torvalds , Andrew Morton , Thomas Gleixner , "H. Peter Anvin" Subject: Re: [PATCH 2/9] x86 idle: remove NOP cpuinfo_x86.hlt_works_ok flag Message-ID: <20110331061247.GA24786@elte.hu> References: <67e90d97e0a77df4acd0c75e1bacc7714e011f3e.1301550524.git.len.brown@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 937 Lines: 30 * Len Brown wrote: > From: Len Brown > > hlt_works_ok was X86_32 only, initialized to 1, and never cleared. > > On 32-bit kernels, this deletes a line from /proc/cpuinfo: "hlt_bug : no" I think you missed the valid usecase where an old CPU with broken halt is booted with the no-hlt boot parameter and does not want to crash in the HLT instruction. That "no-hlt" boot parameter does: arch/x86/kernel/cpu/bugs.c: boot_cpu_data.hlt_works_ok = 0; We can restrict compatibility, but *please* lets do it *explicitly*, not under some 'remove unused code' pretense ... Could you please list all CPU models that are affected? Thanks, Ingo -- 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/