Comment 28 for bug 186264

Dito here, same issue as Alex Magaz,
I fumbled with mouse keys (emulation of pointer movements via keypad),
then wanted to switch it off (it had been on for some time) but didn't remember the hotkey, pressed ctrl for 8 seconds (which launched KDE 3.5's accessibility keys dialog); shortly after that everything was dead.
Switching user (launching new X session) works, switching back to old session --> dead keyboard.

Highly annoyed.

Just found out that I simply had slowed keys ("Verlangsamte Tasten") accessibility feature enabled, had my keyboard working again when disabling it in kcontrol accessibility.

I consider this to be nothing other than an INaccessibility feature. Grrrr.
Describing this handling as "suboptimal" would be an understatement, there's no indication or reminder that keys are slowed (read: "dead" for all usual intents and purposes) by such a large amount (500ms).
Next thing I would have done was killed my _entire_ X session remotely - thankfully I managed to figure out this roadblock
just before doing so.

Almost ranks same scale as persistent "pointer grab" on my list of X server annoyances.