I have several pi's (PI3, latest stable Jessie). They're all used to (only) play short mp4 pmovies in a loop, using omxplayer. Omxplayer is starting up with a short script (in /home/pi/.config/lxsession/LXDE-pi/autostart). There is no user interaction, (except from watching the movie), and PI is only connected to screen with HDMI and one network cable. No other devices attached, an GPIO pins are not used.

Now, it happens sometimes (let's say once every 2-3 weeks) that one of the PI's is displaying a frozen image, so the video stopped somewhere and keeps displaying that screen.

All of the PI's reboot automatically once a week using crontab, and the reliability has improved a lot, yet, those freeze still happen occasionaly...

I have watchdog running, yet it seems such a screen freeze is not considered as a "system freeze" and thus the system is not rebooting. When the screen is freezing, I can still log in (using ssh).

When the image freezes, omxplayer process is still running (checked with top), so making a script for checking running processes (and restart if needed) won't resolve the issue.

The omxplayer log doesn't report abnormal behavior.

I was wondering if there is a way to monitor those kind of screen freezes, and execute a reboot in case they occur. Would there be anything we could get back from the HDMI signal, or read the video buffer (and compare to previous buffer)? Any thoughts or suggestions?

EDIT: added a printscreen of (the top part) of the running processes. screenshot of running processes

Thanks - Pieter

  • 1
    I've been using the pi for quite a while now, (about 120 of them) and ran recently in kind of the same problem but with only one. How much video memory do you have allocated for the pi in the /boot/config.txt file? The default value is gpu_mem=64. Maybe experiment with an higher value?
    – Jeroen
    Feb 23, 2018 at 16:28
  • I've tried this, but doesn't help... Now, when accessing such a "frozen" device, I can't open any new windows (VNC), or can't even open raspi-config over SSH. Memory usage of omxplayer is only in the range of 4%, CPU usage in the range of 1% (I've edited the original question with a printscreen).
    – pieterdp
    Mar 8, 2018 at 17:24


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