Keyboard freezes after some random time

[mikhail-777]

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu
$ lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
$ apt-cache policy xserver-xorg-input-evdev
xserver-xorg-input-evdev:
  Установлен: 1:2.7.0-0ubuntu1.2
  Кандидат: 1:2.7.0-0ubuntu1.2
  Таблица версий:
 *** 1:2.7.0-0ubuntu1.2 0
        500 http://mirror.yandex.ru/ubuntu/ precise-updates/main i386 Packages
        100 /var/lib/dpkg/status
     1:2.7.0-0ubuntu1 0
        500 http://mirror.yandex.ru/ubuntu/ precise/main i386 Packages
     1:2.3.2-5ubuntu1 0
        500 http://ubuntu.mirror.cambrium.nl/ubuntu/ lucid/main i386 Packages

3) What you expected to happen?
I expect that always can use my keyboard without needing unplug it from USB, while computer works, and then plug in again.

4) What happened instead?
I boot my Ubuntu system and successfully work on it in XFCE4 or Unity. But after some random time (hours or days) my keyboard freezes. But if I hold down a button some seconds, then system detect pressing. So to write text I must hold down every button some seconds.
To fix problem I must unplug keyboard from USB and plug in again. Then all will work good until I reboot my system.
Same problem when keyboard is connected to PS/2, but in that case replug in PS/2 does not help.
I can fix problem also by logout. Then Xorg will restart and keyboard starts work normally again, but I am not sure that it is permanent fix as with USB replug in.
I tried to use other keyboard. It does not help.
I tried different kernel versions from 3.2 to 3.13. It does not help.

I think problem is in Xorg or xserver-xorg-input-evdev, because Xorg restarting (logout) helps.

I do not remember when problem is started. Looks like more than 6 month ago, maybe after upgrade to 12.04.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1.2
ProcVersionSignature: Ubuntu 3.2.0-67.101-generic-pae 3.2.60
Uname: Linux 3.2.0-67-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Thu Jul 31 01:21:38 2014
InstallationMedia: Ubuntu-Studio 10.10 "Maverick Meerkat" - Release i386 (20101008)
MarkForUpload: True
SourcePackage: xserver-xorg-input-evdev
UpgradeStatus: Upgraded to precise on 2012-10-23 (645 days ago)

[mikhail-777 (wpr-oxym)]

I fixed the problem.
Looks like I am pressing Shift button for time more than 10 seconds, when I thinking.
Slow Keys are enabled after such type of Shift pressing.
Accessibility and Show Keys are denied in my system, but because of bugs in some desktop environments (such as xfce4), these settings are ignored.
So solution is to add such script in autostart after graphical login to Xfce:

 xkbset -sl # Disable slow keys (if already active).
 xkbset -a # Disable accessibility to prevent it from switching on.

Don't forget to install xkbset before this.

Related bugs with this problem, where you can found discussion of the problem:
https://bugs.launchpad.net/ubuntu/+bug/1002951
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=677173
https://bugzilla.redhat.com/show_bug.cgi?id=816764

To detect problem existance in your system dissable Accessibility in gui setting and then run:
xkbset q | grep "Accessibility Features"

Solution is from here: https://www.unix-ag.uni-kl.de/~guenther/slow-keys.html
If "On" then you have the problem.