[vdr] black screen after recording and playing back at same time

["C.Y.M" <syphir@syphir.sytes.net>]

While testing vdr-1.3.20, I have started to have a major problem with my kernel 
crashing (total lockup and forced hard reset). This is how I reproduce the problem:

1) Record a show on a timer
2) Playback a recording *while* vdr is recording something
3) Stop the playback of the recording and instead of vdr returning to live-tv, 
it just shows a black screen.
4) Start and stop the playback of the recording a few more times and I get an 
irq oops with a full lockup (forcing me to hard reset).

While testing this on a two card system, the black screen was easily 
reproducible but not the total lockup.  This may be specific to a single FF card 
setup.  I can not reproduce this to with vdr-1.3.17+safe threading patches.

Best Regards,
C.Y.M.