Debugging

Hi, I have some problem with streaming recordings in xbmc (they abrupt abort in the stream without any error) so I'd like to see more information on the backend site. How can I configure the debugging tab for that?
I have configured the Debug Log Path, but what I shall put into the Debug Subsystems field? (TvHeadend 3.9.309). Do I have to pass the debug parameter to the process too?

Thanks for any advice.