screen goes black when use vesafb

When I use vesafb and set vga=xxx as kernel option to change the resolution, the screen goes blank at boot time. I know the system is still booting, nothing is wrong except the screen.

I finally found the solution. I appears the framebuffer module is not loaded with the kernel.

The walkthough is to edit /etc/modules.autoload.d/kernel-2.6   (in Gentoo, other distros may have different path) to add these two lines:

fbcon
vesafb