[mythtv-users] X lock when using VDPAU : explanation and work-around

[Jean-Yves Avenard]

Hi

Some people have reported that sometimes they would experience a
complete lock of their system ; either permanently or for a few
seconds : nothing would respond including X

Yeechang reported it in his VDPAU review.

I too started to experience this problem when changing channels from
the Program Guide in LiveTV or when I would move an application's
window on top of mythtv (while watching LiveTV).

The very puzzling thing was that if I started mythfrontend from the
command line ; then it wouldn't happen ; only if I made mythfrontend
starting after a boot.

I knew it wasn't coming from the MythTV code.

So I tried to remember what I did in the past week . I know this isn't
related to the MythTV code. Then I remembered, I played with the
realtime priority.

So I carefully looked at the log, and when started automatically after
login, in the log I see:
2009-02-20 02:36:55.236 Using realtime priority.
2009-02-20 02:36:55.338 OpenGLVideoSync()
2009-02-20 02:36:55.366 Video timing method: SGI OpenGL

When starting from a command line ; I get:
2009-02-20 02:40:11.856 Realtime priority would require SUID as root.
2009-02-20 02:40:11.958 OpenGLVideoSync()
2009-02-20 02:40:11.983 Video timing method: SGI OpenGL

So the difference is one run with real-time priority the other one doesn't.

I edited /etc/security/limits.conf and removed all the bit making
mythtv run with higher priority ... Rebooted

And no more hang !!

So now you have a solution to fix this problem ...

As for why it hangs when using realtime priority is another story ...
Jean-Yves