I have the Mirror Displays enabled on my Linux Mint 15 Cinnamon 64-bit box, which has a GTX 680 graphics card installed with recommended drivers. I selected the top green one in this screenshot.
However, when on the login screen, the display is not mirrored; it's displayed on the primary monitor only.
I really would like to have the WebGL clouds (the flyover one) MDM login screen projected on a 108″ screen before login. Is there any way I could do this?
Edits for updates:
I notice that the Mirror Displays setting is account-specific. Is there a "default" user at the login screen whose settings I could tweak to enable this? I've tried
sudo su -l mdm in an attempt to
cinnamon-settings the display to mirrored, but
sudo su -l mdm has no effect (very strangely): I retain my shell prompt, and a single
exit kills the terminal.