From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Purdie Subject: Re: [PATCH] sony-laptop: allow complex per-value input/output validation Date: Tue, 13 Feb 2007 08:59:08 +0000 Message-ID: <1171357148.6028.5.camel@localhost.localdomain> References: <20070212210107.GA5577@inferi.kami.home> <200702122355.56336.lenb@kernel.org> <49660.85.47.20.193.1171356477.squirrel@picard.linux.it> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from tim.rpsys.net ([194.106.48.114]:52332 "EHLO tim.rpsys.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751178AbXBMJAd (ORCPT ); Tue, 13 Feb 2007 04:00:33 -0500 In-Reply-To: <49660.85.47.20.193.1171356477.squirrel@picard.linux.it> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Mattia Dongili Cc: Len Brown , linux-acpi@vger.kernel.org On Tue, 2007-02-13 at 09:47 +0100, Mattia Dongili wrote: > On Tue, February 13, 2007 5:55 am, Len Brown said: > > On Monday 12 February 2007 16:01, Mattia Dongili wrote: > >> allows consistency between the sony-laptop > >> specific 'brightness_default' and the backlight subsystem 0-based > >> 'brightness'. > > > > Why do we need to have "sony-laptop specific 'brightness_default'" -- > > is that a shortcoming of the backlight subsystem? > > It depends on how do you see it :) > brightness_default is the value that brightness will have at the next (and > later) reboot and it's currently handled as a platform_device attribute. > It would be nice anyway if one such attribute could be added to the > backlight subsystem (I'll provide patches - added rpurdie to the Cc list) > in order to standardize its behavior/interface. The backlight class doesn't really have any reason to know anything about defaults. The current behaviour is that if you want it at a certain 'default' brightness, you set it to this after you register the device. Some devices don't want the brightness changed and want to use whatever it was set to originally. In the case of some other drivers, you can't read the brightness value. With any patches, please keep in mind the changes in http://git.o-hand.com/?p=linux-rpurdie-backlight;a=shortlog;h=for-mm as I've separated out the ops functions from the actual device specific data. Regards, Richard