Is disabling ctrl-alt-backspace really such a good idea? - no.

[Dylan McCall]

Re: SysRQ not working. Try it in a virtual terminal and see if that
works (something harmless, like Alt SysRQ M).

For starters, the SysRQ / Print Screen key becomes SysRQ when Alt is
being pressed.

If you change the GNOME keyboard settings you could find different
results. Is it possible that whether userspace is using the Alt
Printscreen key combination impacts whether the kernel does the Magic
SysRQ stuff?


Thanks,
-Dylan