From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: Commit 7751ab8e600f26e10c2ba12a92d48a4852a51da8 Date: Wed, 13 Apr 2011 17:53:44 +0100 Message-ID: <20110413165344.GA739@srcf.ucam.org> References: <4D9B4094.4010609@absence.it> <20110412152009.GA32032@srcf.ucam.org> <4DA5D45A.9070901@absence.it> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:52814 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757069Ab1DMQx4 (ORCPT ); Wed, 13 Apr 2011 12:53:56 -0400 Content-Disposition: inline In-Reply-To: <4DA5D45A.9070901@absence.it> Sender: platform-driver-x86-owner@vger.kernel.org List-ID: To: Marco Chiappero Cc: platform-driver-x86@vger.kernel.org, Javier Achirica , Mattia Dongili On Wed, Apr 13, 2011 at 06:50:34PM +0200, Marco Chiappero wrote: > I agree. The DSDT of any ALS equipped Vaio provides us 9 backlight > levels (that are LCD/model specific), so the first and the last ones > define our useful operating range, which is always different from > 0-255 (eg. 13-255 for the Vaio S, 52-255 for the Vaio F, 7-182 for > the Vaio Z, 7-213 for the Vaio TT and so on). However the code to > retrieve and use those lower and upper bounds is still lacking > upstream (I, Javier Achirica and many other people are testing a > heavily modified sony-laptop.c written by us which includes lots of > features that we might include soon, but there is no patchset yet). > Moreover it is questionable whether to expose this "wire-range"/fine > grain backlight device, which is intended to be used for an ambient > light based regulation (that requires smooth transitions and > sometimes minimal changes), while for normal backlight operations > the 9 levels already mentioned should suffice. Can this code be merged within the next week? If not I agree that it'd be better to drop this patch for now. I think exposing the full range of (usable) brightness values makes sense, since ALS policy is likely to be determined in userspace - we'll need some way to expose the appropriate mapping, but that's something that needs to be handled generically in the long run. -- Matthew Garrett | mjg59@srcf.ucam.org