Bitfields for Intel 82371MX PCI DMA/PCI DMA expansion registers:
Bit(s)	Description	)
 7-4	reserved
 3	Expansion enabled
 2-0	DMA channel
Note:	The PCI DMA Expansion request lines (REQ[A,B]#/GNT[A,B]#) provide PCI
	  DMA and PCI DMA expansion support.
SeeAlso: #01168,PORT xxxxh"Intel 82371"