It seems XScreenSaver doesn’t allow me to change input method while locked.
This apparently caused me trouble when I forgot to switch
ibus back to English (US) after typing some Cyrillic stuffs using Russian (phonetic) keyboard before locking the screen, as I would not be able to correctly type the password at all.
For now I managed to get out of it the dirty way by force-killing all the xscreensaver related processes from a different terminal. Don’t know if there’s a clean way to at least switch the keyboard layout to the right one from another terminal so I could switch back and enter my password.
On the other hand, does anyone know a screensaver/lockscreen that doesn’t have such issue? Maybe XScreenSaver is not a good idea if you use input methods with very different character sets (e.g. Russian, Greek).