ForceWare drivers support it since 66.93 or such, not that long ago.
Catalyst drivers... well yeah, they support it ever since the first catalyst, actually the ArcadeVGA is just a radeon with a hacked bios, If you delete those "DALCUSTOMCRT" registry keys from the avga drivers, guess what... it outputs everything with 31+ KHz.
Matrox PowerDesk is quite known for letting you define custom stuff, although most likely only used for 15KHz with TVs.
Yeah... Thats how it all started.
looking what gets changed where, how it works, how I can convert binary from/to modelines, then wrote a small frontend and voila... thats it.
However, I later looked into other cards and drivers.
3Dfx was quite easy to figure out as they contain all mode parameters in plaintext (at least the better v3/4/5 drivers do).
Intel GMA however, was more of luck.
I noticed that my fathers notebook did miss some resolutions if I used the "generic" Intel drivers, instead of the HP supplied ones.
So I did a quick registry search and found the difference in some "DTD" keys, but couldn't figure out how they work until someone in the entech (powerstrip) forum mentioned they look like EDID definitions, and a few lines of code later, yeah... there indeed striped EDID defintions.
However, I don't know how to disable the "default" resolution on Intel GMA yet, so Soft-15KHz does not support these Chips yet.
Also my father took the notebook and ran away after I told him about what I was going to try
Theoretically Kyro and Kyro2 cards should work, however I was told that only the first beta drivers for 2000/XP had support for it, and it was later droped.
Also XGI is said to be compatible, but other than a Volari V3 there are no cards available, and the V3 does not. Although the V5 or V8 should do fine, but I don't know anybody owning one.
Yeah... Thats all about it... more or less