[linux-dvb] Lost lock problems over extended periods of time

Andrew de Quincey adq_dvb at lidskialf.net
Wed Jun 8 16:13:54 CEST 2005

On Wednesday 08 June 2005 10:13, Manu Abraham wrote:
> Andrew de Quincey wrote:
> >>>That is sort of what I was thinking in desperation and my first hack :)
> >>>The only thing it didn't do is set the tone/voltage settings again -
> >>>which may explain why the first hack didn't retune - thats what I'm
> >>>trying now - a combination of set tone/voltage plus reset & FE settings.
> >>
> >>But i was thinking whether we would treating the symptom in that case ..
> >>I was wondering why the lock goes off at all in the first case ..
> >
> > Oh yeah, I agree the hack is doing stuff with the symptoms - I'm just
> > trying to identify what fixes it so we can track down the cause.
> >
> > Do the multiswitches where you saw the problem support anything about
> > tone/voltage switching BTW?
> No switches.. connected directly..
> DVB-Card-->Splitter-->Amplifier-->LNB.
> The amplifier was there because of a long RG-11 cable.. The Amplifier
> was near the LNB (approx 10m away, to reduce input noise)

Hi, I've managed to get it to auto-retune. However it is very weird.... All 
I've done is the following in the else clause of "if (s & FE_HAS_LOCK)":

if (fe->frontend->ops->set_voltage)
	fe->frontend->ops->set_voltage(fe->frontend, 0);
if (fe->frontend->ops->set_tone)
	fe->frontend->ops->set_tone(fe->frontend, 0);
fe->frontend->ops->read_status(fe->frontend, &s);
if (s & FE_HAS_LOCK) {
	fe->state = FESTATE_TUNED;

-- if it hasn't relocked I then kick off a retune - but this code wasn't run 
(I've got printks in everywhere so I know for sure).

The channel in question uses voltage/tone SEC_VOLTAGE_13/SEC_TONE_ON (i.e. 
0/0) - I just hardcoded it to those above for quickness.

So I'm not resending the tone burst. I'm not even telling the frontend to 

I'm going see if only one of those is needed to fix the problem now. 
Incidentally, we use nagios to monitor our servers, so I've checked the logs 
going back a year - there is no pattern as to when the channels die.

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