The docs mixed 40-pin connector numbers (AUX pins 15 and 16) with 30-pin panel numbers (VCC 12 to 13, HPD "17 or 21, to be confirmed"). The cleanup picks one convention and writes out the mapping, with HPD at panel pin 17 and connector pin 27. On the first build the panel didn't come back on wake, and the cause was solder joints. Hardware bring-up, firmware GPIO and docs each had their own idea of the pins.