From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22151 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753289Ab0BVVdO (ORCPT ); Mon, 22 Feb 2010 16:33:14 -0500 Message-ID: <4B82F7F4.3090802@redhat.com> Date: Mon, 22 Feb 2010 18:32:36 -0300 From: Mauro Carvalho Chehab MIME-Version: 1.0 To: Devin Heitmueller CC: Andy Walls , Sakari Ailus , hverkuil@xs4all.nl, Linux Media Mailing List Subject: Re: Chroma gain configuration References: <829197381002212007q342fc01bm1c528a2f15027a1e@mail.gmail.com> <1266838852.3095.20.camel@palomino.walls.org> <4B827548.10005@redhat.com> <829197381002220510v64f6e948pfb73ebe4fcc180af@mail.gmail.com> <4B828939.4040708@redhat.com> <829197381002220547n3468019bmdb17f401f7c5b6e1@mail.gmail.com> <4B828D9C.50303@redhat.com> <829197381002221317p42dda715lbd7ea1193c40d45c@mail.gmail.com> In-Reply-To: <829197381002221317p42dda715lbd7ea1193c40d45c@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Devin Heitmueller wrote: > On Mon, Feb 22, 2010 at 8:58 AM, Mauro Carvalho Chehab > wrote: >>> Ok then. I'll add the 15-20 lines of code which add the extended >>> controls mechanism to the 7115, which just operates as a passthrough >>> for the older control interface. >> The better is to do the opposite: extended being the control interface and >> the old calls as a passthrough, since the idea is to remove the old interface >> after having all drivers converted. > > I gave this a bit of thought, and I'm not sure what you are proposing > is actually possible. Because the extended controls provides a > superset of the functionality of the older user controls interface, it > is possible to create a extended control callback which just passes > through the request (since any user control can be converted into a > extended control). However, you cannot convert the extended control > results into the older user control format, since not all the > information could be provided. > > In fact, I would be in favor of taking the basic logic found in > cx18_g_ext_ctrls(), and making that generic to the videodev interface, > such that any driver which provides a user control interface but > doesn't provide an extended control function will work if the calling > application makes an extended control call. This will allow userland > applications to always use the extended controls API, even if the > driver didn't explicitly add support for it. That's exactly the idea: convert all driverst o use ext_ctrl's and let the V4L2 core to handle the calls to the non-extended interface. -- Cheers, Mauro