Possible Solution for Frequent Keyboard Hangups in KDE.

[Nadav Har'El]

On Fri, Sep 14, 2012, Shlomi Fish wrote about "Possible Solution for Frequent Keyboard Hangups in KDE.":
> Hi all,
> 
> in case you are experiencing cases where the keyboard in KDE become
> unresponsive sometimes, then I have discovered a way to predictably
> reproduce this hang-up, and to avoid it. See this KDE bug here:

Sadly, this is a much bigger problem than you describe, which has
plagued various distributions for the last year: People have been reporting -
and it also repeatedly happened to me personally - that X Windows's
keyboard "hangs" while the rest of the computer (as well as the mouse)
continues to work normally. To some people, this "hang" happened several
times a week, bringing Linux's reliability close to that of 1990s MS
Windows :(

Further investigation revealed that the keyboard is NOT actually hung,
but rather in a little-known state called "SlowKeys" - if you press a
key for over a second, it *will* be accepted. If you care enough, you can
actually type something in this weird state. But clearly this state was
meant for people with very specific disabilities - and not for the
general population. So how and why is does one randomly get into this
state?

Continuing the investigation, you'll discover that when X is in a new
and little-known state called "AccessX", it enables the dreaded
"SlowKeys" mode when you press the shift key for 10 seconds. Yes, that's
right - if you daydream with your hand on the shift, bye bye keyboard.

So, you might be asking, why is this AccessX state even turned on by
default? Apparently, it *shouldn't*. X does *not* turn it on by default.
But various buggy Gnome and KDE crap do. On my Fedora, it is GDM (the Gnome
login screen - which is used even if you end up running KDE) which turns it
on (apparently to help people with disabilities to log in) but forgets to
turn it back off when it starts the session. Various window managers also
turn this feature on - it should be off by default unless the user chooses
this feature, but apparently (as I can see from various bug reports in Fedora)
most window managers got this wrong in some way or another. For the GDM
bug (which I described above) is probably causing the problem for most users.

My solution was to install a utility called "xkbset" which knows about
these new X features, and turn them off. "xkbset -a" turns off AccessX,
which turns off that terrible
press-shift-for-10-seconds-and-your-keyboard-is-toast feature.
I run this "xkbset -a" as part of the session startup, and haven't had a
keyboard hang since.

-- 
Nadav Har'El                        |        Sunday, Sep 16 2012, 29 Elul 5772
nyh at math.technion.ac.il             |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |A facility for quotation covers the
http://nadav.harel.org.il           |absence of original thought.