[mythtv] Can't watch live TV with current CVS - need debugging hints

[Dan Schwarz]

My Debian-unstable system successfully runs Myth-0.7 but later builds 
from CVS (even before the frontend/backend split) do not work properly. 
 If I attempt to watch TV mythbackend prints "Switching from None to 
WatchingLiveTV" but nothing else happens - no TV output window is 
created and I see and hear nothing.

I've attached to my debug build of today's CVS - mythbackend with gdb 
and generated this stack backtrace. Basically all it confirms is that 
mythbackend has received the command to SpawnLiveTV but it doesn't seem 
to do anything afterwards.

I'm much more familiar with the mythfrontend program guide etc. code 
than I am with the video display code.  Can anyone provide pointers on 
how to debug this problem. Where to look next?

Thanks,

Dan
dschwarz@bellatlantic.net

(gdb) bt
#0  0x4097cdc1 in nanosleep () from /lib/libc.so.6
#1  0x4076bd0d in nanosleep () from /lib/libpthread.so.0
#2  0x409a102a in usleep () from /lib/libc.so.6
#3  0x0808453a in TVRec::SpawnLiveTV (this=0x829c1f0) at tv_rec.cpp:977
#4  0x080596a8 in EncoderLink::SpawnLiveTV (this=0x828f260)
    at encoderlink.cpp:162
#5  0x08061ac6 in MainServer::HandleRecorderQuery (this=0x829ccf0,
                                                       slist=<incomplete
                                                       type>,
                                                       
commands=<incomplete type>, pbs=0x829bae0)
    at mainserver.cpp:591
#6  0x0805dff9 in MainServer::readSocket (this=0x829ccf0) at
mainserver.cpp:115
#7  0x080720c9 in MainServer::qt_invoke (this=0x829ccf0, _id=47,
                                                         _o=0xbfffe474)
    at moc_mainserver.cpp:95
#8  0x403ab2e9 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#9  0x403ab22e in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#10 0x4063c498 in QSocket::readyRead () from /usr/lib/libqt-mt.so.3
#11 0x4052fbd2 in QSocket::sn_read () from /usr/lib/libqt-mt.so.3
#12 0x4063c589 in QSocket::qt_invoke () from /usr/lib/libqt-mt.so.3
#13 0x403ab2e9 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#14 0x403ab464 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#15 0x4060c8cb in QSocketNotifier::activated () from
/usr/lib/libqt-mt.so.3
#16 0x403c214c in QSocketNotifier::event () from /usr/lib/libqt-mt.so.3
#17 0x40359283 in QApplication::internalNotify () from
/usr/lib/libqt-mt.so.3
#18 0x40359084 in QApplication::notify () from /usr/lib/libqt-mt.so.3
#19 0x4033c673 in QEventLoop::activateSocketNotifiers ()
   from /usr/lib/libqt-mt.so.3
#20 0x4031e4da in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#21 0x4036a8ee in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#22 0x4036a84b in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#23 0x403593da in QApplication::exec () from /usr/lib/libqt-mt.so.3
#24 0x0805c5c3 in main (argc=1, argv=0xbffff9f4) at main.cpp:173