[linux-dvb] Re: Couple of frontend questions

[Oliver Endriss <o.endriss@gmx.de>]

On Tuesday 02 March 2004 23:37, Andrew de Quincey wrote:
> > In the past I did some tests and found that tuning is always faster if
> > zig-zag scan is disabled. So the first thing I do after a check-out is
> > disabling this cra^Wstuff. -> Never had any problems (QPSK BSRU6, Grundig
> > 29504-451).
> 
> Hmm, just had a thought about this... do you know how long in milliseconds it 
> takes to lock with that frontend without zigzag? It sounds like the frontend 
> isn't being given long enough to lock initially, so it kicks off a useless 
> zigzag scan. It certainly shouldn't be any slower WITH zigzag enabled if the 
> frequency was accurate to begin with.

I haven't tried your new code yet. With the old code, tuning was slower
sometimes. Most of the time it worked ok, but sometimes it took considerably
more time to get a lock. I did not look deeper into this, as it was easy to fix
by disabling zigzag scan.

Hm, just an idea: Maybe the LNB needs some extra time to power-up.
To save power, my DiSEqC switch turns off LNB power, if the LNB is not in use.

> If you have a moment to find that out, I can add the modified timings to that 
> frontend driver: my new frontend stuff allows the frontend to override all 
> these sorts of things... should have a patch tomorrow.

Next weekend I'll have some time to try your code. Maybe it works 'as is',
otherwise I'll try to track down the problem.

Oliver


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