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

Andrew de Quincey adq_dvb at lidskialf.net
Tue Jun 7 14:50:56 CEST 2005

On Tuesday 07 June 2005 13:01, Sebastian Frei wrote:
> Am Dienstag 07 Juni 2005 13:51 schrieb Andrew de Quincey:
> > Hi, I've been having (another :) problem with the DVB drivers. Basically,
> > at certain sites and with certain channels, cards seem to lose the lock
> > after a while.... the average is about 10 hours, so I think its unlikely
> > to be that multiswitch incompatability with certain TT DVB-S cards.
> >
> > This doesn't affect all sites or all channels or all cards - the same
> > channels at another site can be rock solid with no issues for months.
> >
> > The driver is supposed to launch a zigzag scan if it loses lock. However
> > this doesn't ever seem to regain the lock with this problem. Simply
> > restarting our streaming software (without a reboot) however, _does_
> > regain the lock (only to lose it again after a while).
> >
> > Snooping with dvbsnoop shows that the signal has been lost, but it does
> > appear to be zigzagging to try and require it, but failing (I see the
> > lock status varying between SIGNAL and SIGNAL|CARRIER|VITERBI, but never
> > above that).
> >
> > The difference between locking initially and losing a lock after a while
> > seems to be the call to dvb_frontend_init(). I'm going to try adding a
> > call to this in to the dvb_frontend_thread() loop if it loses the lock
> > after a while.
> >
> > I'm wondering if anyone else sees this? It seems to plague us constantly.
> > There does not appear to be any discernable pattern - we have a wide
> > selection of TT DVB-S card vintages, and it can happen on any one of
> > them, from cards that were bought 2 or 3 years ago to cards that were
> > bought 2 months ago. :(
> >
> > Does anyone have any ideas as to why it would be happening? The only
> > thing I can come up with is that the frontends just lose the lock after a
> > bit, so they need to be retuned to work around it.
> >
> > I suppose these cards are really meant as consumer grade ones for zapping
> > channels, and not really designed for 24x7 reception on a single channel.
> >
> > _______________________________________________
> > linux-dvb mailing list
> > linux-dvb at linuxtv.org
> > http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
> Hi,
> I have very annoying problems with 2 Nova-S-CI (without CI pins, but need
> budget-ci drivers), maybe related to your problem.
> After watching tv a while and zapping through different channels, I get an
> error in vdr:
> Error: Can't get a lock on device 2
> Femon tells the same. Restarting vdr without reloading the drivers cures
> the problem.
> If you want me to try any patches, send them to me.

Not sure if thats the same thing - I tune a card once and then leave it for 
months (when it works that is :). However if the patch I'm testing fixes my 
problem, I'll send it on to you before committing it to see if it helps.

More information about the linux-dvb mailing list