Scroll Lock in XFCE will not switch KVM

[Todd Pytel]

On Wed, 2012-01-18 at 21:48 -0500, Greg Folkert wrote:
> What kernel are you running?

3.0.0


> This seems to me to not be an XFCE issue. 

Definitely possible, and I just found a workaround noted below. But I'd
still like to understand how this behavior *actually* works under the
hood, because this problem keeps popping up every year or two and has
been for the last 10 years now. It's annoying.

Here's what I can definitely say:

1) Scroll Lock switch works fine in the console - no tweaks necessary.
This suggests it is not a kernel issue.

2) In XFCE, the Num Lock LED works, but the Scroll Lock one does not.
Neither triggers the KVM. Adding the key via xmodmap gets the Scroll
Lock LED working, but still doesn't get the KVM switching.

3) Openbox behaves identically to XFCE. I know Openbox used to switch
properly long, long ago, but I only keep it around as a backup WM and
haven't used it regularly in many years.

4) I don't have a working GNOME install to test with anymore, as I tore
it all out in disgust a few weeks ago. I really don't want to pull it
all back in.

Now, here's the workaround... after some digging, I remembered an
earlier trick about using xset to twiddle the LED's. Sure enough,
doing...

xset led 3 && sleep 0.2 && xset -led 3

...toggles the LED *and* switches the KVM. Yay! What's kind of weird is
that it does this even without the xmodmap line, when the LED doesn't
otherwise work.

I guess this all suggests that something changed about X11's key
handling? But I sure don't understand what's going on. Why would "xset
led" trigger the KVM when the xmodmap'd key doesn't (even though it also
toggles the LED and registers in xev). 

Anyway, I'll take it to the xorg list and see if anyone there has some
insight. Though at this point, I can surely hack together a script and
bind it to Scroll Lock or some other key.

Thanks for pointing me to more general solutions, Greg.

--Todd