I have the same problem as the previous speaker I use mode 1 and get no error
the problem is since the latest kernel update about 1 week ago
i changed the boot/config from kms to fkms so that vcgencmd works again without this change the command does not work ( vcgencmd display_power = 0 or 1)
the pir capture test works but the EXT screen module does not display coundown but only --:-- when i enable it in config
so the countdown is not started so the module does not turn off the hdmi port
if i enter the command vcgencmd display_power = 0 in the terminal it works without problems but it doesn’t work through the module