From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752873Ab1C1FTT (ORCPT ); Mon, 28 Mar 2011 01:19:19 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:37004 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751919Ab1C1FTS (ORCPT ); Mon, 28 Mar 2011 01:19:18 -0400 Date: Mon, 28 Mar 2011 07:18:41 +0200 From: Ingo Molnar To: Len Brown Cc: 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 Subject: Re: [PATCH] x86 APM: delete Linux kernel APM support Message-ID: <20110328051841.GA1342@elte.hu> References: <20110324154505.934a56a0.sfr@canb.auug.org.au> <20110324083959.GE30812@elte.hu> <20110325113048.GC29521@elte.hu> 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 * Len Brown wrote: > > .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, How do we know that? Users are on a bell curve, with a fat tail. If stuff just works - and that's not unexpected from relatively simple (and most likely to be used) APM functionality like APM-poweroff, why should they ever report problems? Removing a driver based on lack of visible feedback is like removing 190,000 apps from a 200,000 apps app store, on the (valid) observation that the top 1000 apps receive 99% of the traffic and use so the remaining 1% are just a maintenance burden. There's value in the concept of knowing that we do not do forced obscolescence in Linux and there's a value in a very broad "there's a driver for that" concept, just like there's value in a very broad "there's an app for that" concept. > 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. Not if most of them use APM-poweroff. I think i even had a desktop box (not a laptop) that supported APM suspend (or am i mistaken there, was APM suspend support only limited to laptops?). Thanks, Ingo