From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:32777 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873Ab2COSHm (ORCPT ); Thu, 15 Mar 2012 14:07:42 -0400 Received: by eekc41 with SMTP id c41so1818682eek.19 for ; Thu, 15 Mar 2012 11:07:40 -0700 (PDT) Message-ID: <4F622FEA.7000903@gmail.com> Date: Thu, 15 Mar 2012 19:07:38 +0100 From: Gianluca Gennari Reply-To: gennarone@gmail.com MIME-Version: 1.0 To: Mauro Carvalho Chehab CC: linux-media@vger.kernel.org, crope@iki.fi Subject: Re: [PATCH 0/3] cxd2820r: tweak search algorithm, enable LNA in DVB-T mode References: <1331832829-4580-1-git-send-email-gennarone@gmail.com> <4F6229D4.8010302@redhat.com> In-Reply-To: <4F6229D4.8010302@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Il 15/03/2012 18:41, Mauro Carvalho Chehab ha scritto: > > Hi Gianluca, > > With regards to LNA, the better is to add a DVBv5 property for it. > > The LNA is generally located at the antenna, and not at the device. > > As you know, more than one device may be connected to the same antenna, > and it is generally not a good idea to have two devices sending power to > the LNA. > > So, it is better to have a way to turn it on via the usespace API. > > Also, as this consumes power, the better is to do it only when the device > is actually used. > > Regards, > Mauro Hi Mauro, I believe this "LNA" is just an internal amplifier that is embedded in the cxd2820r demodulator itself. I have a "condo" antenna so there is no way I can control the power from my apartment as everything is centralized. Many DTT receivers have a "5v power" option to drive the antenna amplifiers on the roof. But almost every antenna (at least here in Italy) has a dedicated power supply, in order to make things simpler for the user. Anyway, a DVBv5 property to control this "power switch" is a good idea. Regards, Gianluca