AGP (Accelerated Graphics Port) is a bus system mainly used to
connect graphics cards to the rest of the system.

If you have an AGP system and you say Y here, it will be possible to
use the AGP features of your 3D rendering video card. This code acts
as a sort of "AGP driver" for the motherboard's chipset.

If you need more texture memory than you can get with the AGP GART
(theoretically up to 256 MB, but in practice usually 64 or 128 MB
due to kernel allocation issues), you could use PCI accesses
and have up to a couple gigs of texture space.

Note that this is the only means to have X/GLX use
write-combining with MTRR support on the AGP bus. Without it, OpenGL
direct rendering will be a lot slower but still faster than PIO.

To compile this driver as a module, choose M here: the
module will be called agpgart.

You should say Y here if you want to use GLX or DRI.

If unsure, say N.

source code:

drivers/char/agp/