I have a problem with my fn keys. If I use my volume hotkeys thru fn key, it works immediately even without releasing the volume hotkey. Now the problem is when I used the brightness, touchpad, and monitor hotkeys. The brightness and multiple display projection hotkey is working but I have to release the key to make it work, the touchpad enable/disable and the monitor on/off isn't working. My laptop model is Asus X454L (intel core i3, nvidia geforce 820m, 4gb ram model) . Any solutions?
PS: I've used a non-asus charger. And I'm thinking it is the cause of the problem.