[vdr] dvb driver failure detection?

Hi all, I'm using a VDR system with 4 skystar2 cards. I'm disabled vdr watchdog and code line who jumps out vdr when the signal is noisy, because when this enabled, and I have noise in one frequency, vdr jumps out and ruins all other input recordings. But there are some times that all recordings fail. I suspect to DVB driver, because VDR records, but file size of recordings are 0, and when I restart system, every things go well again. The question is, how I can detect dvb driver failure, rather than signal failure, to restart system just in driver failure times?

Thanks.