Up Arrow key does not function anymore on my Ubuntu 17.04

Question

The problem on my Dell Vostro 3458 with Ubuntu 17.04 installed. It has been a month that I noticed that Up Arrow key doesn't function and I need to fix this but don't know how??....... Coz it used to work before and I want it to work again.

Answer 1

The first thing to test is whether the key works at all. From a terminal window run:

xev

A window should pop up. Make sure the window has focus (click on it), and then press the Up Arrow key. If the key works, then you will see a KeyPress event and corresponding KeyRelease event show up in the terminal window from which you ran xev.

They will look something like:

KeyPress event, serial 37, synthetic NO, window 0x1400001,
    root 0x20a, subw 0x0, time 39194549, (284,631), root:(284,683),
    state 0x0, keycode 111 (keysym 0xff52, Up), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 37, synthetic NO, window 0x1400001,
    root 0x20a, subw 0x0, time 39194673, (284,631), root:(284,683),
    state 0x0, keycode 111 (keysym 0xff52, Up), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

If you do not see these events, then your issue is probably with the keyboard (check it on a different operating system?).

If you do see the events however, then you should be able to use the keycode given in the event (if you look above, mine says keycode 111 (keysym 0xff52, Up)) to remap the key to your desired functionality.

This answer should be helpful: https://askubuntu.com/a/347382/569198

You can also search to see if any other keycode is already mapped to 'Up' using:

xmodmap -pke | grep Up