To use the VGA EDID on the ADV7850
Just load EDID script and then enable Repeater Map 0x79 -> 1
In power down – if 5V is supplied through the cable the VGA EDID will be available to be read.
The SPI EEPROM needs to be initially programmed before this feature works.
Many sources do not output 5V on the VGA connector.
The VGA cable could be causing an issue. Some cables do not have DDC lines or 5V pin connected - pin9 in VGA connector is 5V power.