Hi, a quick tip today. To keep screen on while lockscreen is activated you must disable DPMS. do it by typing in console:
xset -dpms
Because this setting is only active during current session, you must put it to some startup script. I have my scripts in ~/.config
I use gnome-session-properties for configuring startup scripts.
I even registered to gnome bugzilla to suggest this workaround. Strange, that all those Linux gurus didn't found out this solution, me, Windows guy, had to do it ;)
