Graphics, Video, and Display (D2:F0)
9.4.18
BSM—Base of Stolen Memory Register
Register Address:
Default Value:
5Ch–5Fh
07800000h
Attribute:
Size:
RO, R/W
32 bits
Default
Bit
and
Description
Access
078h
R/W
Base of Stolen Memory (BSM): This field contains bits 31:20 of the
base address of stolen DRAM memory.
31:20
19:0
00000h
RO
Reserved
9.4.19
MSAC—Multi Size Aperture Control
Register Address:
Default Value:
62h
02hh
Attribute:
Size:
RO, R/W
8 bits
This register determines the size of the graphics memory aperture. By default, the
aperture size is 256 MB. Only BIOS writes this register based on address allocation
efforts. Drivers may read this register to determine the correct aperture size. BIOS
must restore this data upon S3 resume.
Default
Bit
and
Description
Access
0h
R/W
Scratch Bits (SCRATCH): These bits have no physical effect on
hardware.
7:4
3:2
00b
RO
Reserved
Untrusted Aperture Size (UAS): Indicates the size of the untrusted
aperture space.
Bits 1:0
Description
128 MB. Bits 28 and 27 of GTT_BASE are read-write
limiting the address space to 128MB.
11
10b
RW
1:0
256 MB. Bit 28 is read-write and bit 27 of GTT_BASE is
read-only limiting the address space to 256MB.
10
01
00
Reserved
Reserved
Datasheet
111
INTEL [ INTEL ]
