The GNOME desktop cannot use the notebook's touchpad

The original use of Ubuntu, the upgrade of GNOME after the touchpad can not be used, can not be said can not be used, it should not be configured and then not use, the specific situation is, you can use the login interface GDM using touch pad and click, but after entering the desktop can not click. Later replaced by arch, installed the GNOME, the problem remains, the solution is as follows

1. Open dconf or enter dconf in terminal

2. Press Ctrl+f to search for touchpad, as follows

　　

3. Select Tap-to-clip to

　　

The GNOME desktop cannot use the notebook's touchpad