I've found that I cannot enter my password at bootup (only Caps Lock has
any effect on my keyboard) until I interact with *any* of the menu items
in the upper right of the LightDM greeter (not just the keyboard
layout). After clicking on any of them, I can press Esc to close the
menu and then type
This bug is observed in Unity in 12.04.4 (and perhaps other versions).
It seems that the original super is being interpreted as an instant,
persistent long-press super ("Super L") rather than as a modifier. One
can test this in Settings > Keyboard > Shortcuts: if you attempt to use
the original s