From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932434AbYBBSG3 (ORCPT ); Sat, 2 Feb 2008 13:06:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752196AbYBBSGW (ORCPT ); Sat, 2 Feb 2008 13:06:22 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58701 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752023AbYBBSGV (ORCPT ); Sat, 2 Feb 2008 13:06:21 -0500 Date: Sat, 2 Feb 2008 19:06:04 +0100 From: Ingo Molnar To: David Brownell Cc: Pavel Machek , linux-pm@lists.linux-foundation.org, kernel list Subject: Re: [linux-pm] sleepy linux self-test Message-ID: <20080202180604.GC26560@elte.hu> References: <20080130131748.GA3796@elf.ucw.cz> <20080202124759.GB25773@elf.ucw.cz> <20080202135037.GC925@elte.hu> <200802020949.23397.david-b@pacbell.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200802020949.23397.david-b@pacbell.net> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian 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 * David Brownell wrote: > On Saturday 02 February 2008, Ingo Molnar wrote: > > > > i'd really love to have a /dev/rtc device compatibility APIs, both > > inside and outside the kernel. > > Unfortunately the /dev/rtc code became a legacy API for good reasons. > > Like not recognizing that all the world's not a PC, with a single RTC > that clones a long-obsolete chip from Motorola ... and not having been > specified in a hardware-neutral manner. Oh, and of course not all > systems actually used the same RTC driver anyway; it's not like there > was just *one* such programming interface to worry about. i dont get it - please give me specific technological reasons why on my PC /dev/rtc couldnt be mapped to /dev/rtc0 - without requiring any user-space changes. The APIs seem mostly covered, or at least mappable. Why should the transition to a new driver require user-level changes? (beyond the obvious extensions, but those should show up as extensions.) In fact i detest the old RTC code with a vengence, so dont understand this as some invitation to flame or something - i simply want YOUR new code to be utilized more! I just dont see the specific technological reasons of why there is no .config switch to switch the legacy /dev/rtc over to the new RTC driver and be done with it. I'd enable it in a heartbeat and would encourage distros to do so. Are there missing APIs? Is the ioctl API totally different? It's impossible to wrap it? I'm not really interested in "this isnt a PC" arguments. The incompatibility is such an obvious migration barrier to me - do you really not see it? Ingo