From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:39084 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755687Ab1FTVCh (ORCPT ); Mon, 20 Jun 2011 17:02:37 -0400 Message-ID: <4DFFB56B.3000802@iki.fi> Date: Tue, 21 Jun 2011 00:02:35 +0300 From: Antti Palosaari MIME-Version: 1.0 To: Rune Evjen CC: linux-media@vger.kernel.org, Markus Rechberger Subject: Re: PCTV nanoStick T2 290e (Sony CXD2820R DVB-T/T2/C) - DVB-C channel scan in mythtv - missing References: <4DF49E2A.9030804@iki.fi> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-ID: Sender: On 06/20/2011 11:55 PM, Rune Evjen wrote: > 2011/6/20 Markus Rechberger: >> to tell the difference the amplifier is for DVB-T2, DVB-C is disabled >> in windows because it's not reliable. >> Technically the chip supports it but the LNA decreases the quality. >> There are already some other PCI boards >> out there with that chip which do not use that LNA which should have a >> better performance with that Sony chip. > > Is it possible to work around this by disabling the lna or is the > quality decreased permanently as part of the hardware design, > independently of whether the lna is enabled or not ? > > I searched the linux-media list and it seems that an lna option was > discussed as a module parameter, but modinfo for the module I use [1] > (using the media_build git repository) doesn't show a lna parameter. > Can the lna be disabled in another way ? LNA is controlled by demod GPIO line. I don't remember if it is on or off for DVB-C currently. Look em28xx-dvb.c file, you can disable or enable it from there (needs re-compiling driver). I also saw BER counter running some muxes during development, but I think all channels I have are still working. And I didn't even have time to optimal parameters for tuner / demod. I will try to examine those later... regards Antti -- http://palosaari.fi/