[mythtv-users] Error opening jump program file buffer

[Michael T. Dean]

On 06/11/2011 12:50 PM, Douglas Peale wrote:
> This bug has existed for too long.
>
> taken from http://code.mythtv.org/trac/ticket/9177#comment:30
...
> The way I read that post, "Until we know it's a MythTV code failure, discussion should occur on list." it implies that the
> developers are currently assuming that all "error opening jump program file buffer" errors are configuration errors and not bugs.

No, simply that that message is useless for figuring out what's 
happening or whether someone is seeing the same issue you reported.  If 
we assumed all "Error opening jump program file buffer" errors are 
configuration errors and not bugs, we would have closed your ticket.

> "And, even once we find it's a MythTV code failure, we need to identify whether it's the same issue that was reported here or if
> it needs its own ticket"
>
> Given that many different kinds of errors generate the "Error opening jump program file buffer" I would like to know how we as
> users are supposed to identify the cause of the problem so we can fix our configurations or open new tickets.

By asking for help on the lists, first, so that someone who understands 
MythTV's inner workings can help verify that it's actually a new, 
unreported issue in MythTV code.  :)

> Perhaps the many different causes of "Error opening jump program file buffer" should be broken out and each given its own error
> message.

The point was that message is an unimportant message--the logging which 
shows what's actually happening happens before that message.  This 
particular message describes only a generic symptom of the actual 
problem--not the cause.

"Error opening jump program file buffer" means we couldn't open the file 
that's supposed to contain the recording.  It's not a helpful message 
for diagnosing (or even identifying whether the same error is occurring) 
because it doesn't say /why/ we couldn't open it.  As you can imagine, 
there are a /lot/ of reasons we might be unable to open a file  In your 
case, the problem is caused because the file we're trying to open is 
empty even after the Live TV tuning timeout (as described by the logs 
you provided in the original ticket description).

2010-11-03 15:12:39.362 
RingBuf(/var/lib/mythtv/recordings/1021_20101103151237.mpg) Error: 
OpenFile(): File too small (0B).

As I mentioned in the post to the ticket, there are a many other things 
that can result in the "Error opening jump program file buffer" 
symptom/message.  Therefore, users who see "Error opening jump program 
file buffer" should not assume that they're seeing the same problem you 
reported just because the title of a bug report has "Error opening jump 
program file buffer" in it.

The last user to post in that thread, Paul, /definitely/ is seeing a 
problem that's unrelated to bug you reported:  "If 'Watch TV' starts on 
a SD channel the first time it is run in a session, changing channels to 
an HD channel will pause for a while then exit to the menu with 'Error 
opening jump program file buffer' message box."  Since he has only a 
single capture card that does only analog SDTV recording, he's not 
switching from SDTV to HDTV.  His is almost certainly a system 
misconfiguration, so if he had asked here, first, we could have told him 
that he needs to check the system configuration things I mentioned 
(and/or others, depending on information provided in the discussion on 
list) and gotten his stuff working--rather than his waiting months for 
us to fix the reported bug, only to find out his system still doesn't 
work, all the while being completely unable to use Live TV.  I would 
/much/ rather get Paul's system working properly right now, but I'm not 
going to discuss how to do so on /your/ ticket--and make your ticket 
impossible to read so that it never gets resolved.

Please see 
http://www.gossamer-threads.com/lists/mythtv/dev/479694#479694 for why 
we need discussion on the list.  It's actually to protect you, Douglas, 
and to ensure the issue you took the time to report is actually 
resolved.  To quote from that post, "So, locking the ticket isn't a 
punishment for those who have something important/useful to say--it's 
instead a way of making sure they're heard."  (The same applies when we 
ask to move discussion to the list and don't lock the ticket, as I chose 
to do this time.  If I made a mistake by not locking it and discussion 
continues on it, I guarantee that I will lock the ticket.  As I 
mentioned, it's already out of hand.  It likely has at least 3 users 
(perhaps all 6 or 7 other users, not including you) discussing different 
problems--some of which may be system configuration issues and not 
MythTV issues, including, at minimum, channel config issues (likely 
requiring a rescan), file system/permissions/NFS issues, bugs that were 
already fixed by Daniel K in d14b660c168b3, ...  So, I started with a 
congenial reminder, and if discussion doesn't stop, I'll lock the ticket.)

Mike