[linux-dvb] Re: CX22702 conexant/leadtek support

[John Dalgliesh <johnd@defyne.org>]

On Tue, 7 Sep 2004, Andrew de Quincey wrote:
> On Tuesday 07 Sep 2004 12:18, John Dalgliesh wrote:
> > On Tue, 7 Sep 2004, Andrew de Quincey wrote:
> > > On Tuesday 07 Sep 2004 11:16, John Dalgliesh wrote:
> > > > On Mon, 6 Sep 2004, Andrew de Quincey wrote:
> > > > > Now that the cx22702 code is there, I've added support for the tuner
> > > > > on the Conexant reference design (Thomson DTT7579) - this is what the
> > > > > Leadtek LR6650 card appears to be as well.
> > > > >
> > > > > I do not have one of these cards - the tuner code is based on my
> > > > > initial analysis for the new Nova-t before I heard about Steve's
> > > > > driver. I cannot confirm it works correctly as it has a different
> > > > > tuner. It should do though. The cx22702 code _may_ need some
> > > > > additional tweaks if the reference design is wired slightly
> > > > > differently.
> > > >
> > > > I can confirm that the tuner config is correct for the DTT757Xs that
> > > > are used on DVICO's FusionHDTV DVB-T Lite .... not that that is
> > > > probably any help to you since you are concerned with a completely
> > > > different board :D
> > >
> > > Are those at all based on the conexant reference design out of interest?
> >
> > Not sure, but if so then they didn't think very much of it - it's got a
> > Zarlink MT352 demod and a (cheaper? older?) Fusion 878A as the PCI bridge.
> >
> > So no, probably not ;)
>
> Aha - one question, am I right about it not having a SAW (7/8MHz switchable
> bandwidth) filter? Robert pointed out that maybe the driver I was looking at
> just hadn't written that piece of code - I've got no way of knowing.

Sorry, I have no idea! In fact I think I have even less information than
you on this tuner (only the control word settings for each freq band).

It is worth noting 'tho that DVICO's main market for their DVB-T cards
(currently) appears to be Australia [most likely because it has 'HDTV' in
its title which could cause much confusion in Europe :]. So I would expect
that whatever setting they put in would be 7 MHz by default.  And since
you guys are working off a reference design intended primarily for the
European market (right?) its default would be 8 Mhz. The control setup is
the same so probably no filter.

I'm also guessing that Chris Pascoe is one person on this list who can
really answer the question. Much extrapolation involved in that guess, but
reason being that in his linux driver additions for the MT352 (still not
committed to linux-dvb..?) for the FusionHDTV DVB-T1 (non-lite version),
there is a bit of code in the (LG) tuner config that goes:

#if IN_GERMANY
        tuner_regs[3] |= 0x08;  /* Activate IF SAW filter */
#endif

(Presumably this define should be changed to bandwidth==8 and probably
already has, i haven't downlaoded it recently)

So, when he releases his drivers for the DVB-T Lite we will hopefully all
find out! Or he might see this and answer (or, more likely, tell me to
stop my long-winded idle speculation :)

{P^/