https://wiki.gentoo.org/wiki/Uvesafb
http://www.funtoo.org/Uvesafb
The list of resolutions supported by the VBIOS (the graphic card) is listed at:
cat /sys/bus/platform/drivers/uvesafb/uvesafb.0/vbe_modes
See in /usr/src/linux/Documentation/fb/uvesafb.txt