M4 gpio jitter

Andrea, thank you for testing with oscilloscope!
Please, do me a favor and change "Persist Time" in the oscilloscope to 30 seconds (or better infinite).
In this mode all pulses get drawn one on top of the other (see my posted picture from Oct 4).

You can force the jitter by starting an application (eg AbiWord…).

 

When I Shutdown Linux it's still the same output jitter...

 

But less often jitter...
Also when I stop xserver I have less often jitter...