HDMI not working if plugged after complete boot

I have installed ubuntu server and then installed LXDE.
Everything works fine. But if I haven’t plugged HDMI and after boot when plugged the screen is blank.
How can I force rock pi 4b to initialize hdmi if cable is not plugged.

I have the same problem. I just turn the monitor on first before I turn on the CPU.

Can’t force to initialize HDMI? Since once the HDMI is initialized if I plugged the cable and remove it again plugged it still works. In raspberry pi it can be force initialized - https://raspberrypi.stackexchange.com/questions/2169/how-do-i-force-the-raspberry-pi-to-turn-on-hdmi

Make sure you have /etc/udev/rules.d/60-drm.rules and usr/local/bin/drm-hotplug.sh. These two handles the HDMI hotplug event.

Thanks, Both file are present. Only the issue was that /usr/local/bin/drm-hotplug.sh execute bit was not enabled.

After issuing sudo chmod +x /usr/local/bin/drm-hotplug.sh it started working.