Re: Some keys on the keyboard do not work

[rhkramer@gmail.com]

On Monday, August 10, 2020 07:56:43 AM Eugen Dedu wrote:
> I have a Dell Latitude 5580 laptop, and have been a happy debian
> unstable user for 20 years.  I have a very weird problem with its
> builtin keyboard which slows down my work significantly (ctrl-c, ctrl-x,
> ENTER etc. do not work):
> 
> Since several months ago some keys on my keyboard do not work, in all
> the applications (e.g. gnome-terminal, emacs, thundebird, firefox).
> When I press on them, very often nothing happens (usually, I press on
> them for 10 seconds to make appear the character), sometimes the key
> appears twice, and sometimes it works flawlessly.  When it works, it
> works for several minutes or several hours; similarly, when it does not
> work, it does not for several minutes or hours or days.  I use very
> often suspend/resume, I also use xmodmap and awesome window manager, but
> I suppose this is irrelevant.
> 
> The problematic keys are found on the last row: xcvm,. (but zbn work)
> and the bottom keys (ctrl, alt, window, however space works always
> correctly), plus ENTER key.
> 
> I have always thought that it is a X problem which will get fixed.
> Interesting, a few days ago I noticed that on grub I have the same
> problem: c and ENTER did not work.  So now I wonder if it is not a
> hardware problem, however sometimes it works for a long time!
> 
> I have looked at Xorg.0.log, without seeing anything wrong.
> 
> How can I track down where the problem is, and fix it?

I hesitate to suggest what I'm going to suggest -- so I'd suggest you wait 
until you hear any responses from people that can suggest either a software fix 
or a software test.  (Oh, see last line, maybe try plugging in an external 
keyboard (if that is possible) and see if you have the same problem.)

I suspect it is a hardware problem, and what I would do is get the manual for 
the laptop and look into how hard it might be to clean the keyboard.

You might try blowing out (or vacuuming) the keyboard (with canned air or a 
vacuum cleaner / blower with tools with small orifices).

But if that doesn't work, and no one has a better suggestion, I'd look into 
trying to disassemble the keyboard to some extent and examining it and trying 
to clean it.

I used to do this often with desktop keyboards, I guess I've been better 
lately at keeping them clean.  Laptop keyboards can be much more difficult to 
dis- and re-assemble and keep them working.

Hmm, one test I can think of -- try plugging in an external keyboard and see 
if you have the same problems (if there is a USB port (or other port for an 
external keyboard).