Bug#523946: xserver-xorg-input-synaptics: VertScrolling stops working after update to version 1.1.0
Mirko, there is one more report about the edges changing at runtime or
after suspend, can you check if this is what you're experiencing?
Also, finally found the upstream bug about inaccurate edge calculation:
i dont find any bug, which I think is related to my problem. Which bug you mean?
also I don't think that the upstream bug is my problem. The first use after reboot is fine, but then the touchpad stops scrolling.