[mythtv] Fix for Firewire Recording Endless Errors Warning: No Input in xxx msec

Peter Bennett pgbennett at comcast.net
Mon Feb 6 21:27:06 UTC 2012

I have been irked by this problem for several months now. This seems to
be something that has existed in mythtv for years. At random times, the
linux firewire recorder gets itself into a mode where it is recording
nothing and displaying endless messages:

2011-08-27 14:25:42.175 LFireDev(F45FD447BBFC0000), Warning: No Input in
50 msec...
2011-08-27 14:25:42.299 LFireDev(F45FD447BBFC0000), Warning: No Input in
100 msec...
2011-08-27 14:25:42.374 LFireDev(F45FD447BBFC0000), Warning: No Input in
150 msec...
2011-08-27 14:25:42.450 LFireDev(F45FD447BBFC0000), Warning: No Input in
200 msec...

It never recovers and this continues to fill many megabytes of log file
until the end of the recording time.

For more details see bug log ticket #10277, which has been marked "Won't
fix". (http://code.mythtv.org/trac/ticket/10277)

Would it be useful to re-open that ticket and assign it to me?

I have developed the fix and it is working in my setup. It recovers from
the error and loses about half a second of recording.

There is code in the linux firewire driver to do a "bus reset" when
these errors occur. In my setup, this code does not fix the error, in
fact makes it worse by resetting the p2p parameters of the set top box.
Bus reset is optional and can be turned off in the backend
configuration. I have it turned off.

Does anybody know if the "bus reset" serves any purpose. Perhaps with
other set top boxes it may fix this error?

Currently in my patch, if the new code I have developed does not fix the
problem, it allows the bus reset to proceed, and if that also does not
fix the problem within 30 seconds, fails the recording.

Perhaps I should remove the "bus reset" code altogether if it serves no
purpose and my code handles the problem?

I am going to test this for a few weeks and make sure it fixes the
problem consistently and does not cause other problems. I only have one
set top box to test with. Is anybody who uses firewire and has this
problem interested in testing the fix? How do we get it tested on other
set top boxes and other cable tv providers?

Once I have tested it for some time I will post the patch in the ticket
system. In the meantime if anybody wants to test the patch please let me

Peter Bennett

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