Touchad tap-to-click stops working randomly on lenovo x201

[odin_ago]

I have a lenovo x201 laptop and run gentoo linux with kde5.

After a few days (sometimes a few weeks) after restart, the follwing problem appears: When I use tap-to-click or two fingers scrolling on the touchpad, nothing happens.

This behavior disappears if I press one of the following keys and release them less than in 1 second: Ctrl, Alt, Win (but not Shift). And it reappears again if I press any of these keys (Ctrl, Alt, Win) and keep it pressed for more that 1 second.

I don't know what makes this problem appear "in general" (when I just start my computer, tap-to-click works even if I hold ctrl long-pressed).

Did anyone have a similar problem? Is it possible to fix it at least temporarily, i. e. to run something without restarting so that tap-to-click does not stop working even if I hold the ctrl key for a long time?