[mythtv-users] Problem with a second DVB card, help needed

Otto Kolsi otto at kolsi.fi
Fri Sep 22 18:36:11 UTC 2006

I have a following DVB cards related problem and I'm not sure if it's
related to Myth or DVB drivers / kernel.

I've used one Technisat Airstar 2 DVB-T card succesfully with Myth for 
many months. Now I'm trying to get two of these cards to work at the 
same time (FC5, 2.6.17-1.2187_FC5smp) but haven't succeeded yet.

With all the other apps (dvbscan, dvbstream, kaffeine, mplayer) I can
successfully tune to channels, and watch programs with both cards. With
mplayer I can succesfully watch two different programs from separate 
cards at the same time.

Problem is that when I try to use these two cards *at the same time* 
with Myth, the second card is not working. First card records program 
fine but although Myth starts to record a program, the recording is 
never made with the second card (the file does not exist).

And more strangely, after this kind of failure, if I stop the backend 
I'm not anymore able to use any other apps with the failed card. Tuning 
doesn't work etc. After reboot everything is okay again. How is this 
possible? Could apps using DVB API misuse the card somehow so that it is 
leaved to non-working state? Or does this clearly show that this is 
kernel / driver issue?

Both cards work separately with Myth. I can record a show with card 1, 
stop backend, update card priority so that second card gets higher 
priority, start backend again and successfully record a show with the 
second card.

The problem is simultaneous usage of cards. I know that there are lots 
and lots of people using multiple DVB cards without problems. And it 
feels like driver / kernel  issue.. but how is mplayer able to use both 
cards then and myth not?

Any ideas what is going on or how to troubleshoot this further?

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