AC82G41SLGQ3 Datasheet, PDF(62/604 Page) Intel Corporation – Intel® 4 Series Chipset Family

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AC82G41SLGQ3 Datasheet, PDF (62/604 Pages) Intel Corporation – Intel® 4 Series Chipset Family

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System Address Map

3.2.2

3.2.3

Table 7.

TSEG

TSEG is optionally 1 MB, 2 MB, or 8 MB in size. TSEG is below IGD stolen memory,

which is at the top of Low Usable physical memory (TOLUD). SMM-mode processor

accesses to enabled TSEG access the physical DRAM at the same address. Non-

processor originated accesses are not allowed to SMM space. PCI Express, DMI, and

Internal Graphics originated cycles to enabled SMM space are handled as invalid cycle

type with reads and writes to location 0 and byte enables turned off for writes. When

the extended SMRAM space is enabled, processor accesses to the TSEG range without

SMM attribute or without WB attribute are also forwarded to memory as invalid

accesses. Non-SMM-mode Write Back cycles that target TSEG space are completed to

DRAM for cache coherency. When SMM is enabled, the maximum amount of memory

available to the system is equal to the amount of physical DRAM minus the value in the

TSEG register, which is fixed at 1 MB, 2 MB, or 8 MB.

Pre-allocated Memory

Voids of physical addresses that are not accessible as general system memory and

reside within system memory address range (< TOLUD) are created for SMM-mode,

legacy VGA graphics compatibility, and GFX GTT stolen memory. It is the

responsibility of BIOS to properly initialize these regions. Table 7 details the

location and attributes of the regions. Enabling/Disabling these ranges are described in

the (G)MCH Control Register Device 0 (GCC).

Pre-allocated Memory Example for 64 MB DRAM, 1 MB VGA, 1 MB GTT Stolen

and 1 MB TSEG

Memory Segments

Attributes

Comments

0000_0000h â 03CF_FFFFh

03D0_0000h â 03DF_FFFFh

03E0_0000h â 03EF_FFFFh

03F0_0000h â 03FF_FFFFh

R/W

SMM Mode Only -

processor Reads

R/W

R/W

Available System Memory 61 MB

TSEG Address Range & Pre-allocated

Memory

Pre-allocated Graphics VGA memory.

1 MB (or 4/8/16/32/64/128/256 MB) when

IGD is enabled.

Pre-allocated Graphics GTT stolen memory.

1 MB (or 2 MB) when IGD is enabled.

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Datasheet

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