try this because its a raspberry pi thing not a op thing. its not an easy feature to add.
in the terminal
sudo nano /boot/config.txt
add this line to the file somewhere.
hdmi_blanking=1
ctrl x then y and enter..
sudo reboot
let me know if that works for you
in the terminal
sudo nano /boot/config.txt
add this line to the file somewhere.
hdmi_blanking=1
ctrl x then y and enter..
sudo reboot
let me know if that works for you