Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756917Ab1CaHCK (ORCPT ); Thu, 31 Mar 2011 03:02:10 -0400 Received: from vms173013pub.verizon.net ([206.46.173.13]:60411 "EHLO vms173013pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752323Ab1CaHCI (ORCPT ); Thu, 31 Mar 2011 03:02:08 -0400 Date: Thu, 31 Mar 2011 03:02:00 -0400 (EDT) From: Len Brown X-X-Sender: lenb@x980 To: Ingo Molnar 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 In-reply-to: <20110331061247.GA24786@elte.hu> Message-id: References: <67e90d97e0a77df4acd0c75e1bacc7714e011f3e.1301550524.git.len.brown@intel.com> <20110331061247.GA24786@elte.hu> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1078 Lines: 35 > > 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? "no-hlt" existed only for 32-bit, and there were exactly zero automatic invocations of it. "idle=poll" does the same thing -- sans change a line in /proc/cpuinfo. Do we really need both? thanks, -Len -- 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/