[mythtv-users] DVB stops tuning - partial solution

Kevin Bailey ke-myth at retriever.dyndns.org
Wed Nov 28 16:06:57 UTC 2007

I've been monitoring my system fairly closely since it started
failing to record shows. The symptom was, after mythbackend ran
for a few days, it would start making empty recordings. Trying
to watch live TV revealed the problem: The tuner was hosed, and
not providing data. The only thing that would bring it out of
this state was to reset the back-end and the driver. According
to others on the list, the act of changing the channel was what
might be putting it into this state.

I created a crontab entry to reset everything daily but I'd
still get lots of lost recordings. Since I don't watch that many
channels, if it was happening when it changed channels, that
would have to mean that the failure rate was close to 50%. This
was especially odd since I could switch channels manually and
not have a problem.

I eventually noticed that it would get into its bad state
between a morning reset and an afternoon recording.  But in this
case, it was never even changing channels. I couldn't figure out
what it was doing in between that would break it.

I finally found out. I went through the logs more carefully and
realized that, to gather EIT information, it must tune to *all*
the channels. Furthermore, it was doing this, it seemed, every 5

I then realized when my problems started: When zap2it shut us
off. That was when I switched to using EIT.

I've now turned off EIT scanning. (It wasn't complete anyways.)
Hopefully, with my cron job still running daily, I will get
nearly all my recordings. I also now have a another good reason
to sign up for Schedules Direct.

I will experiment with less drastic solutions. I suspect that it
gathers EIT every 5 minutes only from the channels that it
didn't get it from the previous cycle, which basically means the
channels that don't provide the information ever. So a
potentially less drastic solution is to simply turn it off the
channels that don't provide it. It will still do *some*
background tuning however, so this approach would only lower the
probability of a hosing. Besides, SD works for all the channels.

Hope this helps others.

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