Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933034AbXBLP5i (ORCPT ); Mon, 12 Feb 2007 10:57:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933011AbXBLP5i (ORCPT ); Mon, 12 Feb 2007 10:57:38 -0500 Received: from vervifontaine.sonytel.be ([80.88.33.193]:63498 "EHLO vervifontaine.sonycom.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933034AbXBLP5h (ORCPT ); Mon, 12 Feb 2007 10:57:37 -0500 Date: Mon, 12 Feb 2007 16:57:35 +0100 (CET) From: Geert Uytterhoeven To: Pavel Machek cc: "Rafael J. Wysocki" , Arjan van de Ven , nigel@nigel.suspend2.net, LKML Subject: Re: NAK new drivers without proper power management? In-Reply-To: <20070212150410.GA17400@elf.ucw.cz> Message-ID: 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 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1788 Lines: 41 On Mon, 12 Feb 2007, Pavel Machek wrote: > > > "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'? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/