Comment # 3 on bug 93879 from Franklin Titus

I am having similar issue on AMD HD 7870 GPU, openSUSE Tumbleweed, and Kernel
4.4.0-1.2. I cannot say for sure the trigger, however, once the screen locks
requiring a password, the password field becomes disabled although mouse and
keyboard remain fully functional. In fact, it would seem the entire lock screen
becomes unresponsive to both mouse and keyboard, and CTRL+ALT+Backspace needs
to be employed in order to restart the session.