you can create a edid file form your screen, so you do not need to learn it at start
It has script for RPI , but it looks like doesn't know what is RPi ?
LibreELEC:~ # sh getedid gpu
getedid: line 32: lspci: not found
getedid: line 34: lspci: not found
GPU is not supported
LibreELEC:~ #