Bitfields for Intel AGP Capability Identifier:
Bit(s)	Description	)
 31-24	reserved
 23-20	major version of supported AGP revision
 19-16	minor version of supported AGP revision
 15-8	offset of next capability (0 = none)
 7-0	PCI capability ID (2 = AGP, 0 = disabled)
SeeAlso: #01142,#01159,#01129