[mythtv-users] Problem controlling external tuners in new upgrade using mythtv V0.25.3

[Craig Huff]

On Sat, May 17, 2014 at 1:32 AM,  <f-myth-users at media.mit.edu> wrote:
snip...
>
> Try replacing the calls to the scripts with calls to a script
> consisting of some or all of
>
>   #!/bin/bash
>   id >> /tmp/DEBUG
>   groups >> /tmp/DEBUG
>   set >> /tmp/DEBUG
>   printenv >> /tmp/DEBUG
>
> and see if you get the same results when you call it as you, as the
> mythtv user, and as when myth itself tries to change channels.  If you
> don't, try either changing the scripts' environments to match the
> by-hand calls and see if they work, or try changing the by-hand
> calling environment to match the mythtv environment and see if it
> fails.
>
> This will also tell you if your script is getting called at all when
> mythtv tries to change channels, of course; maybe myth isn't even
> trying.
>

I took your suggestion and created the wrapper scripts.  Manual
testing worked fine, but it appears they don't even get called by
myth.  I verified that the fully-specified paths to the channel
changing scripts are correct (no typos!), but nothing is getting added
to the /tmp/DEBUG file when myth is supposed to be changing a channel!
 I re-verified that the scripts have world read-execute permissions,
as do the scripts that really do the work.  All the scripts write
things that should end up in the log file, so they're never getting
called.

I did notice that mythmetadatalookup is being called when I'm trying
to change the channel in live-tv mode.  Is it possible that something
else is getting stuck before the channel-changing script gets called?

When I change the channel, I often (but not always) get a message
about framebuffering failed too many times and then myth goes back to
the main frontend screen. There is information in the screen info
panel to the effect that the video signal level dropped out and/or the
system couldn't lock on to the video signal.  Since it never called
the routine to change the channel, I don't understand this at all.

I tracked the contents of several myth***.log files while I made an
attempt to change the channel while in live-tv mode and noted these
things:
  * mythpreviewgen complained that /home/mythtv/.mythtv/config.xml
could not be opened for writing, but it seemed to succeed at grabbing
a preview anyway.
  * while it shouldn't be relevant, for full disclosure's sake, I also
have a configuration problem with the audio controls and mythfrontend
reported that ALSA couldn't register device /dev/mixer.
  * mythfrontend reported numerous messages about waiting for video
buffers that all end with 32 "A"s in a row followed by a "P".

Your ideas were great, but no Eureka! ensued.  I really hate grasping
at straws, but I've completely run out of ideas on this one.

--
Craig.