Thanks for sharing the timing values. The appropriate modeline would probably look like this:
Modeline "2048x2048@60" 357.23 2048 2090 2410 2816 2048 2051 2054 2114 -HSync -VSync
However, please note that this requires a frequency higher than what a DVI
output is capable (330MHz). On the other hand, my understanding is that
the analog signals on a DVI-D output can go up to 400 MHz? There might
by a chance that there is some nvidia driver specific xorg-option to "break"
the 330MHz limit (maybe "ConnectedMonitor" "CRT" to force assuming a