[linux-dvb] Re : Re : How to solve the TT-S2-3200 tuning problems?

manu eallaud at yahoo.fr
Sat Jun 28 17:19:50 CEST 2008


Le 28.06.2008 08:44:12, manu a écrit :
> Le 21.06.2008 05:14:46, Ales Jurik a écrit :
> > Hi,
> > 
> > I've tried to see where the problem is for some time. My opinions
> and
> > results 
> > of some debugging work is included.
> > 
> > I'm ready to cooperate in debugging of this driver.
> > 
> > BR,
> > 
> > Ales
> > 
> > On Saturday 21 of June 2008, manu wrote:
> > > 	Hi all,
> > > there are several threads about TT-3200 not being able to lock on
> > > different channels depending on FEC/symbol rate/modulation.
> > > Now what kind of experimentation could provide enough data to
> solve
> > > them? For example would it be possible that some knowledgeable 
> guy
> > here
> > > posts:
> > > -datasheets/programming guide for the tuner/demod if no NDA...
> > 
> > Yes, such documents are under NDA, I don't have access to it.
> > 
> > > -post the source of a prog that could gather data when tuning to 
> a
> > > given transponder.
> > > -or anything else that this/these persons think would improve the
> > > understanding of the problems.
> > > HTH
> > > Bye
> > > Manu, who would like to watch the final of the euro cup in HD ;-)
> > 
> > The point from which I've checked the driver is file stb0899_priv.h
> > (enum 
> > stb0899_modcod). There are defined values for all possible 
> > FEC/modulation combinations. We could see that 8PSK modulations 
> have
> > values 
> > from 12 to 17 (for debugging). 
> > 
> > But no initial values are used for 8PSK modulation for registers
> csm1
> > to csm4 
> > as the stb0899_dvbs2_init_csm is called only for QPSK ( condition 
> is
> > and-ed 
> > with INRANGE(STB0899_QPSK_23, modcod, STB0899_QPSK_910) ).
> > 
> > I'm not sure if this is the reason of problems, but I could get 
> lock
> > (very 
> > unstable - lock is active for few minutes, than for minute or so
> > disappeared 
> > and so long) after few minutes staying tuned on some 8PSK channels. 
> > 
> > Maybe if set some registers (don't know if csm1-csm4 is enough) to
> > initial 
> > values depending on FEC/modulation it would be possible to get lock
> > within 
> > seconds like it is with QPSK.
> > 
> > In the driver there are also some pieces of code depended to
> > FEC/modulation, 
> > but only STB0899_QPSK_XXX is used for such pieces of code. Not
> > possible to 
> > find STB0899_8PSK_XXX depending code. Isn't it necessary? Or such 
> > code
> > is 
> > missing and the casual lock is done by hw automation? 
> 
> One more datapoint: I have one transponder which has only HD Channels 
> on it; the only difference with the other transponders (which are 
> working great using TT 3200) is the FEC (and the fact that it is
> MPEG4, 
> but that changes nothing for getting the lock); symbol rate and 
> modulation are the same. But it does not lock. Here is the dmesg of a 
> simpledvbtune session: one with a success on another transponder, and 
> then a failure on this transponder.
> I'd like to know where to put some printks or tweak the code to be
> able 
> to debug this, if someone with the know-how could explain a bit. I 
> can
> 
> definitely do some coding, but without data it is kind of hard.
> HTH
> Bye

just to precise a bit more: all transponders are DVB-S with QPSK 
modulation (at least this is what is advertised in the dvb tables).
BYe
Manu




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