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I have just upgraded to Ubuntu 13.04 and the left Ctrl key has stopped working. How would I go about diagnosing the problem?

I had to downgrade my X server to enabled legacy graphics card support, but everything else seems to be fine.


Edit:

xev output for left Ctrl:

KeymapNotify event, serial 38, synthetic NO, window 0x0,
    keys:  4294967235 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
           0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

xev output for right Ctrl:

KeyRelease event, serial 38, synthetic NO, window 0x3e00001,
    root 0xc3, subw 0x0, time 10191367, (-206,519), root:(827,656),
    state 0x14, keycode 105 (keysym 0xffe4, Control_R), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False
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Execute command: xev –  konrad May 4 '13 at 18:41
    
I think @konrad wants to see the event generated when you press the left ctrl key. In my machine, it shows something like this when I pressed Left Ctrl key KeyPress event, serial 37, synthetic NO, window 0x3e00001, root 0x291, subw 0x0, time 98520655, (301,491), root:(1582,519), state 0x10, keycode 37 (keysym 0xffe3, Control_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False –  thefourtheye May 4 '13 at 19:02
    
KeyRelease event, serial 37, synthetic NO, window 0x3e00001, root 0x291, subw 0x0, time 98520903, (301,491), root:(1582,519), state 0x14, keycode 37 (keysym 0xffe3, Control_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False –  thefourtheye May 4 '13 at 19:03
    
Interesting - does this mean I have a key mapped that is suppressing the normal ctrl key behaviour? –  Thomas Bratt May 4 '13 at 19:09
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1 Answer 1

I had a similar problem. I would press "Ctrl+Alt" and the computer would restart (with a message that "Ctrl+Alt+Del" was pressed). Then I noticed that the problem is with the Ctrl key - in the terminal, when I pressed just the left Ctrl key it would output sometimes e.g. "5~;5~" other times it would keep printing "-----------" or "vvvvvvvvvvvvvvvvvv". The output in the terminal without X was different and also a bit erratic.

This started happening after I upgraded to 13.04. I also had the "locate mouse pointer" feature enabled from one of the earlier versions of Ubuntu and Gnome - it would render red/brown circles around the mouse pointer when you press the left Ctrl key. After disabling this feature [1], the problem seems to have gone away.

[1] Where is "Show position of the mouse when the Control key is pressed"

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