[linux-dvb] Lost lock problems over extended periods of time
Andrew de Quincey
adq_dvb at lidskialf.net
Wed Jun 8 23:34:49 CEST 2005
On Wednesday 08 June 2005 18:40, Oliver Endriss wrote:
> Andrew de Quincey wrote:
> > It seems I only need to set the tone when it loses lock. Here is my
> > current hack:
> > ...
> > When it dies, I see the following in dmesg:
> > DVB: LOST LOCK - attempting retune
> > DVB: REGAINED LOCK WITH SIMPLE TONE setting
> > So what the hell would cause that? I've got printks in the
> > set_tone()/set_voltage()/etc functions, and nothing is calling them. All
> > it does once the initial lock is gained is request the frontend lock
> > status.
> Which frontend driver, iirc stv0299?
Yes. As far as I know all the cards I've seen with this problem are based on
Note though, most cards with this frontend are rock solid. In most cases,
they're attached to the _same_ multiswitches as the ones with the problem.
> If some code would write to register 0x08, it might turn off the 22kHz
> tone. Check whether the corresponding register has been modified.
Already checked that - the register 0x08 remains the value I set last.
When the tone is set on for the first time during the tune:
CURRENT 0x08 value: 46
NEW 0x08 value: 47
However, when it loses the lock:
CURRENT 0x08 value: 47
NEW 0x08 value: 47
So I'm setting 0x08 to the _same_ value it is currently. Yet doing this causes
the signal to be regained in less than 100ms. If I don't do this, lock is
_never_ regained, no matter how long I leave it (however, if I retune by
stopping+starting our application it locks immediately).
Incidentally, my latest test was to set the tone every 60 seconds in the
frontend loop. This didn't work though - it still lost the lock, and went
into the patch I posted earlier and regained it simply by setting the tone.
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