[linux-dvb] Re: Frontend experimental patch v1

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

On Tuesday 09 March 2004 01:26, Andrew de Quincey wrote:
> On Tuesday 09 March 2004 00:19, Oliver Endriss wrote:
> > On Monday 08 March 2004 20:39, Andrew de Quincey wrote:
> > > On Saturday 06 March 2004 13:55, Oliver Endriss wrote:
> > > > Until now, I found that FE_SET_PARAMETERS is always called twice,
> > > > with fe->state==2 and fe->state==4. Is this intentional?
> > >
> > > Yeah, thats the frontend-core auto inversion. The stv0299 hardware
> > > doesn't support auto inversion by itself.
> >
> > Anyway, it's not necessary to tune twice when switching transponders.
> 
> Yup, will be gone in -v2 of the patch

Great.

> > After _successful_ tuning, the current inversion setting can be saved.
> > The _saved_ value should be tried first. If tuning fails, the inversion
> > setting should be toggled.
> >
> > This way, every frontend can implement auto inversion (in software).
> 
> Currently it sets it to AUTO until it gets a lock. Then it remembers inversion 
> setting it found.. but it never goes back to AUTO again (until a new 
> SET_FRONTEND is done)
> 
> Do you have a particular reason in mind for it returning to AUTO if the lock 
> is lost?

No, this was a simplification. A transponder will hardly ever change
signal inversion on the fly. (At least I hope so.)

Anyway, someone wrote that there is a transponder which transmits an
inverted signal. So it's necessary to return to AUTO when tuning to a
new transponder.

Usually the inversion setting won't change. So it is better to try the
last working inversion setting first. This will speed up tuning.

Oliver


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