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

manu eallaud at yahoo.fr
Sat Jun 28 14:44:12 CEST 2008


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
Manu




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