Keyboard input lost or out of order after pause in typing, on Ubuntu 12.04

[cwmccabe]

I am experiencing a problem with keyboard input whenever I stop typing for around 3+ seconds. Several of the first few keypresses are lost or out of order.

This occurs while I'm typing this Ubuntu Forums post if I stop for 3 seconds, or it happens in any other window (e.g. a terminal) after I pause for 3+ seconds before I start typing. It even happens when I try to press Ctrl+Alt+T to open a terminal -- after 3+ second pause, the first time I hit Ctrl+Alt+T I get no response and have to do it a second time for the terminal window to open. The problem is easily reproducible.

Ex. If I wait 3 seconds and then try to type "asdf", only "sa" appears, or sometimes just "a" appears. (Note that the "sa" were the first letters of "asdf", but now in reverse order). But after I've backspaced and deleted the mess, I can continue typing as usual.

This started happening suddenly today on a 12.04 Ubuntu that has been installed and in heavy use for several months. I have rebooted without success.

The only change I have made recently was to install Okular last Friday (the last time I had the machine turned on). I have now uninstalled Okular but this didn't fix the problem.

The keyboard is a USB keyboard. I am not experiencing any lag on input from the USB mouse. I do not have any Universal Access features enabled (Sticky Keys, Slow Keys, etc). I have tried Unity2D but the same problem occurs.

. . . . . . .

Any advice about what I can do to further diagnose and resolve this problem?


[EDIT] I could not find any solutions, so I upgraded to 12.10 as a last resort. The problem is not occurring now -- but I am still interested if anyone has ideas about what was happening and/or how to resolve it in case it occurs again.