Keyboard not working in lightdm after inactivity and lock until I switch user

[folaht]

Could be related to this:

Keyboard not working in firefox until I open a new window

“After some time”, not sure when exactly it occurs, let’s say ten minutes, firefox will refuse to take any keyboard input until a new window is opened. It’s quite annoying and thought it might be due to the specific firefox version, but I’m still having this issue after having updated firefox. [edit] I just updated my firefox extensions. I can imagine that it might be caused by this, so I’ll wait and see if the problem still occurs.

Just like firefox, after some inactivity I cannot the keyboard on lightDM.
Only after switching user does the keyboard work.
Mouse input did work as far as I can remember.