From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964992AbXBLQzz (ORCPT ); Mon, 12 Feb 2007 11:55:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964994AbXBLQzy (ORCPT ); Mon, 12 Feb 2007 11:55:54 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:50999 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S964982AbXBLQzP (ORCPT ); Mon, 12 Feb 2007 11:55:15 -0500 Date: Mon, 12 Feb 2007 17:55:01 +0100 From: Pavel Machek To: Geert Uytterhoeven Cc: "Rafael J. Wysocki" , Arjan van de Ven , nigel@nigel.suspend2.net, LKML Subject: Re: NAK new drivers without proper power management? Message-ID: <20070212165501.GA18101@elf.ucw.cz> References: <1171058269.1484.64.camel@nigel.suspend2.net> <1171059433.8675.195.camel@laptopd505.fenrus.org> <20070210193851.GA3956@ucw.cz> <200702102320.39531.rjw@sisk.pl> <20070212150410.GA17400@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > > "If the device requires that, implement .suspend and .resume or at least > > > ^^^^^^^^ > > > > define .suspend that will always return -ENOSYS (then people will know they > > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > ^^^^^^^^^^^^^^^^^^^^ > > > > will always return -ENOSYS." > > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > > > It's nicer if you don't have to implement dummy functions at all. > > > > Unfortunately, drivers currently assume "NULL == nothing is needed", > > so we'd have t do big search & replace... > > Which means you also cannot easily keep track of which driver supports > suspend/resume and which doesn't, as there will always be drivers where a > missing suspend/resume function is correct. > > Wouldn't it be more sensible to have > > .suspend = suspend_nothing_to_do > > instead, and reserve NULL for `not yet implemented'? It would be. Patch would be welcome :-). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html