From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764525AbXJOGmj (ORCPT ); Mon, 15 Oct 2007 02:42:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754646AbXJOGmc (ORCPT ); Mon, 15 Oct 2007 02:42:32 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:37653 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752507AbXJOGmb (ORCPT ); Mon, 15 Oct 2007 02:42:31 -0400 Date: Sun, 14 Oct 2007 23:41:49 -0700 From: Andrew Morton To: Stephen Rothwell Cc: Olaf Hering , linux-kernel@vger.kernel.org Subject: Re: apm system does not power off anymore Message-Id: <20071014234149.39a4f08a.akpm@linux-foundation.org> In-Reply-To: <20071015163720.09630ee4.sfr@canb.auug.org.au> References: <20071012125426.GA16626@aepfle.de> <20071014232316.4beb160f.akpm@linux-foundation.org> <20071015163720.09630ee4.sfr@canb.auug.org.au> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Oct 2007 16:37:20 +1000 Stephen Rothwell wrote: > On Sun, 14 Oct 2007 23:23:16 -0700 Andrew Morton wrote: > > > > Also, it's bad that the operator has to provide some special boot command-line > > option to make the machine work properly. Please consider this to be a > > bug. Has it always needed apm=power-off? > > It has always been that way because the behaviour of APM on SMP is not > defined. We discovered early that it will work (at least for powering > off) for most SMP machines as long as the APM calls are done on CPU 0. > However on an SMP machine that does not cope, very bad things happen - > thus the operator has to explictly enable the power off behaviour on an > SMP box. (On UP power off is enabled by default.) hrm, OK. But it could have been controlled by a more-user-friendly runtime knob, I guess. Not that it's worth changing that now.