OK I changed if [ -z "$DISPLAY" ] && ! pidof usplash >/dev/null; then to if ! ps -Af | grep -q 'bin/X.* vt$(fgconsole) ' && ! pidof usplash >/dev/null; then in /etc/init.d/console-setup here. Now it works with su - too.
** Attachment added: "console-setup-detect-X-patch" http://librarian.launchpad.net/6872911/console-setup-detect-X.patch -- updating console-setup in X destroys screen https://launchpad.net/bugs/93338 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs