I have a 5" display that runs entirely on the HDMI connection to the Pi, including power. Unfortunately, the display has a backlight which can't be switched off unless it is completely disconnected from power. Is there a way to shut off the power output to the HDMI port from the RPi OS?
I've tried commands like
tvservice -o which was advised in other threads to shutoff HDMI displays. This indeed cuts the video feed to the HDMI output, but the power remains (apparently +5V on pin 18 is HDMI standard).