There's actually custom AMD GPU firmware called CRT emudriver for older cards that still had analogue output to push custom modelines to CRTS: http://geedorah.c

There's actually custom AMD GPU firmware called CRT emudriver for older cards that still had analogue output to push custom modelines to CRTS: http://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=1009#p1009 http://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=1009... It's used in the retro gaming community to get hardware accurate video output from emulators.