This enables support for text mode selection on kernel startup. If
you want to take advantage of some high-resolution text mode your
card's BIOS offers, but the traditional Linux utilities like
SVGATextMode don't, you can say Y here and set the mode using the
"vga=" option from your boot loader (lilo or loadlin) or set
"vga=ask" which brings up a video mode menu on kernel startup. (Try
"man bootparam" or see the documentation of your boot loader about
how to pass options to the kernel.)

Read the file Documentation/svga.txt for more information
about the Video mode selection support. If unsure, say N.