BE/FE (with remote FEs too) on MB 10.04 x86_64 with MythTV 0.25 (currently 2:0.25.0+fixes.20120608.648f0ae-0ubuntu0mythbuntu1) using one PVR-500 connected to Dish Network receiver using tuner0/S-Video1 and an OTA digital receiver feeding NTSC to tuner1/Composite1:
Ever since upgrading to 0.25 a few days after release, I've had never ending trouble with the PVR-500 becoming unresponsive with I/O errors at random times but becoming increasingly likely the longer the BE goes between restarts (and/or ivtv driver reset [with rmmod and modprobe]). This creates 0-bit recordings in MythTV and breaks LiveTV. Backend logs show 'StartEnconding Failed' and 'socket went unconnected' errors.
If I quit MyhthTV frontend and stop the backend (and wait for threads to exit), 'cat /dev/video0 > ./test.mpg' also produces 0-bit test.mpg (and cat does not exit cleanly). v4l2-ctl commands will error out.
Once I do a 'sudo rmmod ivtv' and 'sudo modprobe ivtv', the card will work properly for a random period of time (and may even fail upon its very first use by MythTV).
Within MythTV, no particular pattern of channel changes or other usage scenarios seems to impact the likelihood of the card failing at any particular time; LiveTV is no more likely to create a problem than scheduled recordings. All capture cards (not just on the BE) have been deleted and reconfigured several times (with at least one iteration of removing all cards, all video sources, and rebuilding channels from scratch). In fact, I've gotten into the practice of removing and reconfiguring the capture cards after each and every MythTV update...their tuning timeout is the 12s default. I have tried running with ONLY the /dev/video0 (connected to Dish) configured as well (to no help).
Outside of MythTV I have not been able to bork the card; no amount of channel changes, v4l2-ctl commands, connects/disconnects with vlc/mplayer/whatever elicits the symptoms.
This began immediately on upgrade and has never stopped malfunctioning on any release since.
I've searched and probed:
It is exactly the symptoms noted in this (now closed) bug: http://code.mythtv.org/trac/ticket/9846, except that it is not confined to LiveTV. It appears this bug may be a duplicate of 9830 which has been fixed, and the fixes are in the version I'm using. It also may be related to 9177 which is now closed as invalid.
I have no idea how to proceed in debugging this issue other than to try the card in a totally fresh 10.04 or 12.04 installation, but I don't relish that thought much.