knoppix vga=0x317

In your example above, you used the hexidecimal code. You have not yet tried the decimal version.

Knoppix vga=791 for example.

This is what I used to get my Kyro II card going in my Knoppix HDD install.

See chart below.

vga=
773 = 1024x768x8
775 = 1280x1024x8
791 = 1024x768x16
794 = 1280x1024x16

Hope this helps.

sakiZ