Intel D15343-003 - Manual (Page 60)

Intel
®
82854 Graphics Memory Controller Hub (GMCH)
60 D15343-003
4.8.15 DAFC – Device and Function Control Register (Device #0)
This 16-bit register controls the visibility of devices and functions within the GMCH to
configuration software.
4.8.16 FDHC – Fixed DRAM Hold Control Register (Device #0)
This 8-bit register controls a single fixed DDR SDRAM hole: 15-16 MB.
Address Offset:
Default Value:
Access:
Size: 54-55h
0000h
Read/Write
16 bits
Bit Description
15:8 Reserved
7 Device #2 Disable :
1: Disabled.
0: Enabled.
6:3 Reserved
2 Device #0 Function #3 Disable :
1: Disable Function #3 registers within Device #0 and all associated DDR SDRAM and I/O ranges.
0: Enable Function #3 within Device #0.
1 Reserved
0 Device #0 Function #1 Disable :
1: Disable Function #1 within Device #0.
0: Enable Function #1 within Device #0.
Address Offset:
Default Value:
Access:
Size: 58h
00h
Read/Write
8 bits
Bit Description
7 Hole Enable (HEN): This field enables a memory hole in DDR SDRAM space. Host cycles
matching an enabled hole are passed onto ICH4-M through Hub interface. The GMCH will ignore
Hub interface cycles matching an enabled hole.
NOTE : A selected hole is not re-mapped.
0: None
1: 15 MB–16 MB (1MBs)
6:0 Reserved