[Solved] Gnome sometimes not recognizing keystrokes

Hello everyone!

I am using Manjaro now for more than three years and never had any problems. After this long time I recently completely reinstalled my computer. Since then I experienced a very weird bug about my keyboard: Sometimes, apperently randomly, certain (but always the same) keys do not work and I have to click them multiple times until the character is actually typed. The keys where I observed this to happen are the left Ctrl key (and only the left, not the right!), the Alt key and the ?. I wouldn't really bother about this but the randomly non-working left control key is extremely annoying. Also, and I noticed this only in the login screen, the 5 and 6 sometimes don't work for a few seconds.

Weirdly enough, the output of

xev -event keyboard

seems to respond to all keystrokes in all circumstances, so I am very certain that this is not a hardware problem.

Does someone have any idea what might be wrong?

Best,
Jan

For starters welcome to the forums
Please disable all Extensions and try again after a reboot.
If that does not fix it then I would next create a new user and see if everything is fine with the new users keyboard.
Obviously make sure you are completely up to date with $ sudo pacman -Syyu

2 Likes

I tried both your suggestions and the problem persists across new users and if all extensions are disabled. My system is upgraded. The fact that the problem also persists on the login screen indicates that it should not have anything to do with a user configuration, right?

Not 100 % sure, good guess though. If you really think it is a Gnome bug then head over to the Gnome bug report or maybe their forums and make a report.
It does not seem to be Manjaro related at the moment.

I took a more detailed look at the output of xev -event keyboard and it actually seems like the problem already persists there. So for example for pressing the right ctrl-key and then releasing it after one second, I get the following output:

KeyPress event, serial 28, synthetic NO, window 0x5c00001,
    root 0x1aa, subw 0x0, time 207627359, (1227,380), root:(1277,485),
    state 0x0, keycode 105 (keysym 0xffe4, Control_R), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x5c00001,
    root 0x1aa, subw 0x0, time 207628419, (1227,380), root:(1277,485),
    state 0x4, keycode 105 (keysym 0xffe4, Control_R), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

Now sometimes the output looks similar for the malfunctioning keys, but if the corresponding keys stop working properly again, the output looks like this:

KeyPress event, serial 28, synthetic NO, window 0x5c00001,
    root 0x1aa, subw 0x0, time 208794842, (762,494), root:(912,700),
    state 0x0, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x5c00001,
    root 0x1aa, subw 0x0, time 208794859, (762,494), root:(912,700),
    state 0x4, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

So basically just pressing left Ctrl is interpreted as pressing it and releasing it after 17 ms as can be seen from the timestamp. Again, this does not happen every time. After some time everything seems to work properly again (and once it works it seems to keep working for some time).

I am really not sure if this can be a hardware fault since multiple keys are affected in the same way and the problem occured for all the keys simulataneously. Can we somehow use this as a new starting point for finding the problem?

Edit: Just a quick update, I tried a live USB and the keyboard did not work there either. External keyboards worked as expected and after I exchanged the internal one, everything was fine again, so it was a hardware problem after all. I thought it was weird that so many special keys dropped out, but I guess that makes sense as they are used way more often than other keys. Thank you for your thoughts!

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