[mythtv-users] Mythfrontend lockup

[Stephen Worthington]

On Mon, 7 Oct 2019 20:48:29 -0700, you wrote:

>When we left this problem last I was instructed to do my CTRL-ALT-BS to
>reset the gui and record the time then look at the mythfrontend.log.
>
>My wife called my downstairs, I noted the time as 20:30, did the
>CTRL-ALT-BS. Then about 2 minutes later Myth came back up.
>
>Here are three lines out of the log. The first is well before the event and
>I just include it to show that the next line was in fact all that was
>printed immediately before the event. The last line is the first in a
>series of Setup records.
>
>Oct  7 19:48:33 NewMyth mythfrontend.real: mythfrontend[1643]: I
>CoreContext mythrender_vdpau.cpp:615 (CheckOutputSurfaces) VDPAU: Added 2
>output surfaces (total 4, max 4)
>Oct  7 20:27:18 NewMyth mythfrontend.real: mythfrontend[1643]: E Decoder
>mythplayer.cpp:3504 (DecoderGetFrame) Player(1q): Decoder timed out waiting
>for free video buffers.
>Oct  7 20:32:30 NewMyth mythfrontend.real: mythfrontend[6495]: I
>thread_unknown signalhandling.cpp:194 (SetHandlerPrivate) Setup Interrupt
>handler.
>
>Also, from my desktop upstairs I could see that the backend kept running
>and mythweb was fine. Myth screen shot did not respond.
>
>I would like help on what might be causing this and what I might do to
>eliminate the 2 minute wait between CTRL-ALT-BS and system restart. Under
>Mythbuntu, there was no delay.
>
>Thank you.
>
>Allen

When mythfrontend is not locked up, how long does restarting X with
Ctrl-Alt-Backspace take if you try manually shutting down mythfrontend
before you do it?  If it takes much longer when mythfrontend is
running, then the problem will likely be the bug that mythfrontend
(and all MythTV GUI programs) has, where it only partially shuts down
when given a SIGTERM (kill or kill -15) request.  A second SIGTERM is
needed to get it to shut down fully, and the shutdown of X may be
waiting for mythfrontend to finish shutting down.  This shutdown bug
is a fairly longstanding now, but if I remember correctly, you used to
be using a quite old version of MythTV and it may not have had that
bug.

I have now written a script to kill mythfrontend properly.  It is
available to be downloaded from my web server:

http://www.jsw.gen.nz/mythtv/killm

I would suggest putting it in /usr/local/bin and setting it up to be
allowed to be run from any user (so that the MythTV users can run it):

sudo su
cd /usr/local/bin
wget http://www.jsw.gen.nz/mythtv/killm
chown root:root killm
chmod u=rwx,og=rx killm
exit

The script first optionally kills the /usr/bin/mythfrontend script
that runs and automatically restarts the real mythfrontend program
(/usr/bin/mythfrontend.real).  Then it does two kill -15 commands on
mythfrontend.real, and finally checks to see if mythfrontend.real has
actually shut down and if not, does a kill -9 on it.  It should take
less than 2 seconds to kill mythfrontend in the worst case, and in the
best case should take just over 0.1 s.

If you put any parameter text on the command line after the "killm"
command, such as "killm x", that tells killm to first kill the
/usr/bin/mythfrontend script so that /usr/bin/mythfrontend.real will
not be restarted.  If you want that done always, see the comment in
the script telling you how to set that up.  I use killm without that
option when I have mythfrontend lock up playing one of my video files
(I have several that trigger a mythfrontend lockup bug).  I have yet
to have killm fail to kill mythfrontend, but my mythfrontend lockups
may not be the same as yours.

I would suggest that the next time you have your mythfrontend problem,
if possible you ssh into the MythTV box and run "killm" and see if
mythfrontend.real will die and be restarted.  If it does, then you
could look at making it possible to run killm from a button on your
remote control.  If you can not use ssh to get to a command prompt,
try using Ctrl-Alt-F1 on the MythTV box and login from that console to
do the killm command.  You need to run killm from either the same user
as mythfrontend is run from, or from root, or using sudo.  Once you
have run killm, swap back to the GUI screen using Ctrl-Alt-F7.