linux-4.8.3-gentoo # dmesg | grep -i agp
[    0.000000] Found U3-AGP PCI host bridge.  Firmware bus number: 240->255
[   79.271669] Linux agpgart interface v0.103
[   79.286888] agpgart-uninorth 0000:f0:0b.0: Apple U3H chipset
[   79.300467] agpgart-uninorth 0000:f0:0b.0: configuring for size idx: 64
[   79.308235] agpgart-uninorth 0000:f0:0b.0: AGP aperture is 256M @ 0x0
[   82.883029] agpgart-uninorth 0000:f0:0b.0: putting AGP V3 device into 8x
mode
[   82.883040] radeon 0000:f0:10.0: putting AGP V3 device into 8x mode