Is there a command-line way to turn off the backlight of an external monitor connected to laptop through HDMI?
This works on laptop's monitor:
echo 10 | sudo tee '/sys/devices/pci0000:00/0000:00:01.0/0000:02:00.0/drm/card0/card0-LVDS-1/nv_backlight/brightness'
But I couldn't find something like this for the external monitor.
xbacklight doesn't work on both laptop's monitor and external monitor (and I don't even know if it could turn off the backlight).
Also I'm aware of
xrandr --output HDMI-1 --brightness 0 and
xrandr --output HDMI-1 --off but the first one still leaves the mouse cursor visible (maybe find some way to hide it?), and the second one completely turns off the monitor, which I don't want.