From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751660Ab1C0Vk6 (ORCPT ); Sun, 27 Mar 2011 17:40:58 -0400 Received: from mail1-out1.atlantis.sk ([80.94.52.55]:37424 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750968Ab1C0Vk5 (ORCPT ); Sun, 27 Mar 2011 17:40:57 -0400 From: Ondrej Zary To: Len Brown Subject: Re: [PATCH] x86 APM: delete Linux kernel APM support Date: Sun, 27 Mar 2011 23:40:31 +0200 User-Agent: KMail/1.9.10 Cc: Ingo Molnar , Stephen Rothwell , x86@kernel.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Linus Torvalds , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton References: <20110325113048.GC29521@elte.hu> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201103272340.42748.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 26 March 2011 06:01:38 Len Brown wrote: > > Regardless of removal, i'd suggest a "this code is not supported" kind of > > WARN() message to the APM code today, into .39 - to see whether it pops > > up anywhere - and mark it for -stable as well. > > Okay, can do. > > > .42 removal might be too fast, considering the typical release schedule > > of Linux distributions. And i'm still doubting the removal itself: we are > > adding lots of special-purpose subarch drivers to arch/x86/ as we speak > > (the embedded mess coming to x86) - which drivers will be tomorrow's APM > > code. On what grounds do we treat APM support differently? > > > > Our general compatibility with old hardware is an *asset* that we should > > value. > > My guess is that the customers have died off, > and so the code is no longer an asset, but a maintenance liability. > > If there is a buzzing community of people running 2011 > linux kernels on their ancient laptops in APM mode, > then the APM maintainer would probably know about them. > > Personally, my oldest usable laptop is a T23 from March 2002. > It supports APM and ACPI (it shipped with Win2K). > Linux works well on it in ACPI mode, but doesn't even boot in APM mode. > If anybody was really using the latest kernel in APM mode, > I suspect this laptop would boot... > > Is there somebody on LKML that has a older laptop than me > and is able to get it to boot in APM mode? I'd be astonished > if there was not. Are they willing to regularly test changes > to the upstream kernel to make sure that APM still works? > If yes, where have they been for the last 5 years? I just tested 2.6.38-rc4 on a desktop board and it works (power off at least). If using Grub2, linux16 command must be used instead of linux in grub.cfg (otherwise loading apm module will fail with "apm: BIOS not found"). I also have some working laptops with APM but haven't tried recent kernels yet. > I suspect when there is nobody using the latest kernel on mrst, > then the latest kernel can delete support for mrst, and nobody will care. > Like APM, it will probably undergo "maintenance without testing", > aka bit rot, for a period before that happens. -- Ondrej Zary