The manual, the REAL manual, will list all the supported display modes, probably in a table.

You'll need to get comfortable web searching for some answers. "linux edid" is the search I'd use. I don't remember the command used 7 months go, 5 times. Because I have an nvidia card, the way I forced the correct EDID information to be used is proprietary and only for nvidia. Sorry.

That's really all I can offer. Good luck.