Dear Maintainer,
I am sporadically running into an issue where light-locker shows the password
prompt normally, but after unlocking I'm left only with a black screen.
I can see and move the cursor and it sometimes changes from an arrow to a hand
(as if it's responding to what's drawn under the black screen), but I
can't do much more. The only solution I've found is going to a TTY (with
CTRL+ALT+F*) and restarting lightdm.
It happens almost every time when unlocking after suspending/hibernating, but
I've also seen it after a normal lock.