From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH 0/3] Generic sysfs support for ACPI ALS and other ALS devices Date: Wed, 5 Aug 2009 18:19:31 +0200 Message-ID: <20090805161931.GA9749@elf.ucw.cz> References: <1249290657.2670.250.camel@rzhang-dt> <20090804132129.GH18974@elf.ucw.cz> <1249434170.2670.386.camel@rzhang-dt> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:41410 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933979AbZHEQTh (ORCPT ); Wed, 5 Aug 2009 12:19:37 -0400 Content-Disposition: inline In-Reply-To: <1249434170.2670.386.camel@rzhang-dt> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Zhang Rui Cc: linux-acpi , Linux Kernel Mailing List , Len Brown , Richard Purdie , Matthew Garrett , Greg KH On Wed 2009-08-05 09:02:50, Zhang Rui wrote: > On Tue, 2009-08-04 at 21:21 +0800, Pavel Machek wrote: > > On Mon 2009-08-03 17:10:57, Zhang Rui wrote: > > > Hi, all, > > > > > > This is the patch set I made to introduce ACPI ALS device driver > > > and a generic sysfs I/F for all the ALS devices, like ACPI ALS, > > > platform ALS, etc. > > > > > > Patch 01 introduces the ACPI ALS device driver. > > > > > > Patch 02 introduces ALS sysfs class. > > > Two sysfs I/F are created for each ALS device. > > > /sys/class/als/alsX/illuminance: > > > the amount of light incident upon a specified surface area. > > > /sys/class/als/alsX/mappings: > > > ambient light illuminance to display luminance mappings > > > that can be used by an OS to calibrate its ambient light policy > > > this is what I got on a test box: > > > cat /sys/class/als/als0/mappings > > > ???Illuminance Adjustment > > > 0 70 > > > 10 73 > > > 80 85 > > > 300 100 > > > 1000 150 > > > > There's one value per file for sysfs... You should definitely have the > > header. > > > > Is there chance to already return adjusted values, avoiding this > > uglyness? > > No, > For a ALS policy, user space should set a brightness level as the base > point, i.e. the backlight when display adjustment is 100. > and then uses the adjustment values gotten from this mappings to > calculate the actual brightness level the display should be put in. Ok, so just make the code return only the "adjustement" -- userspace does not really need to know "illuminance" and you can do the mapping in the kernel AFAICT. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html