From mboxrd@z Thu Jan 1 00:00:00 1970 From: InKi Dae Subject: Re: [patch] added brightness feature to lcd class. Date: Fri, 13 Nov 2009 12:13:54 +0900 Message-ID: <90b950fc0911121913o2b5285f5w23c706aed3203e65@mail.gmail.com> References: <90b950fc0911020050q3bc3fae8j954ec6ed73d79b5@mail.gmail.com> <1257809705.29038.82.camel@dax.rpnet.com> <90b950fc0911091926v32dc1c44n1018322390282bc0@mail.gmail.com> <1257842597.29038.162.camel@dax.rpnet.com> <90b950fc0911102217o41aea871u3a5d9e44c947fe3c@mail.gmail.com> <1257931717.29038.298.camel@dax.rpnet.com> Mime-Version: 1.0 Return-path: In-Reply-To: <1257931717.29038.298.camel@dax.rpnet.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Richard Purdie Cc: linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Kyungmin Park , Andrew Morton , Pavel Machek Ok, I understood your answer. Just it was my idea for AMOLED LCD Panel. Both of them (AMOLED, TFT-LCD) do same thing in terms of brightness control as you said. Thank you, Richard. Best Regards, InKi Dae. 2009/11/11 Richard Purdie : > On Wed, 2009-11-11 at 15:17 +0900, InKi Dae wrote: >> 2009/11/10 Richard Purdie : >> > So you've tried this, what was the problem? Perhaps post this driver >> > code to illustrate your problem? >> >> all the cases worked fine. >> it's not whether lcd driver has a problem or not. >> I mean it's design issue of lcd class. AMOLED LCD Panel DOESN'T NEED >> backlight device. >> and I should have added brightness control feature to AMOLED LCD Panel >> driver not using backlight class >> because they have no BACKLIGHT DEVICE. >> >> in point of view AMOLED LCD Panel, brightness control is perfomed by >> gamma setting, not backlight power controlling. > > The question is whether this gamma control does the same thing as what > we've traditionally used the backlight brightness control for. As I > understand it, the answer is yes and to userspace making it appear as a > backlight brightness control makes sense. > > The userspace view of the world is key and the fact there is not a > traditional physical backlight in the hardware isn't really an issue. > > Why would we want to create two userspace interfaces doing the same > thing which would mean we just have to complicate userspace drivers? > Symlinking just makes things confusing. > > Cheers, > > Richard > > >