12th Generation Intel® Core™ Processors Datasheet Volume 2 of 2
ID | Date | Version | Classification |
---|---|---|---|
767625 | 07/13/2023 | Public |
PCI Mirror of GMCH Graphics Control (MGGC0_0_2_0_PCI) – Offset 50
Mirror of GGC register from GTTMMADR Space at offset 0x108040.
Bit Range | Default | Access | Field Name and Description |
---|---|---|---|
15:8 | 0x5 | RO/V | Graphics Memory Size (GMS) This field is used to select the amount of Main Memory that is pre-allocated to support the Internal Graphics device in VGA (non-linear) and Native (linear) modes. It corresponds to DSM (Data Stolen Memory region) region. The BIOS ensures that memory is pre-allocated only when Internal graphics is enabled. Hardware does not clear or set any of these bits automatically based on IGD being disabled/enabled. BIOS Requirement: BIOS must not set this field to 0h if IVD (bit 1 of this register) is 0. BIOS Requirement: Given new sizes allow down to 8MB allocation, BIOS has to ensure there is sufficient space for WOPCM and basic GFX Stolen functions. |
7:6 | 0x0 | RO/V | Graphics Translation Table Memory Size (GGMS) This field is used to select the amount of Main Memory that is pre-allocated to support the Internal Graphics Translation Table. The BIOS ensures that memory is pre-allocated only when Internal graphics is enabled. GSM is assumed to be a contiguous physical DRAM space with DSM, and BIOS needs to allocate a contiguous memory chunk. Hardware will derive the base of GSM from DSM only using the GSM size programmed in the register. Hardware functionality in case of programming this value to Reserved is not guaranteed. 0x0:No Preallocated Memory 0x1:2MB of Preallocated Memory 0x2:4MB of Preallocated Memory 0x3:8MB of Preallocated Memory |
5:3 | 0x0 | RSV | RESERVED (Reserved_0) The field 'Reserved' in register 'PCI Mirror of GMCH Graphics Control' does not have a description in the BXML |
2 | 0x0 | RO/V | Versatile Acceleration Mode Enable (VAMEN) Enables the use of the iGFX engines for Versatile Acceleration. |
1 | 0x0 | RO/V | IVD (IVD) 0: Enable. Device 2 (IGD) claims VGA memory and IO cycles |
0 | 0h | RO | Reserved |