Intel® 865G/865GV Chipset Datasheet - download.intel.nl - Intel

Register DescriptionNotes on Pre-Allocated Memory for GraphicsThese register bits control the use of memory from main memory space as graphics local memory.The memory for TSEG is pre-allocated first and then the graphics local memory is pre-allocated.An example of this theft mechanism is:TOUD equals 62.5 MB = 03E7FFFFhTSEG selected as 512 KB in size,Graphics local memory selected as 1 MB in sizeGeneral System RAM available in system = 62.5 MBGeneral system RAM range00000000h to 03E7FFFFhTSEG address range03F80000h to 03FFFFFFhTSEG pre-allocated from03F80000h to 03FFFFFFhGraphics local memory pre-allocated from03E80000h to 03F7FFFFhVGA Memory and I/O Space Decode Priority1. Integrated Graphics Device (IGD), Device 2.2. PCI-to-PCI bridge, Device 1.3. Hub Interface.VGA Memory Space Decode to IGDIF IGE = 1 AND IVD = 0 AND Device 2 Mem_Access_En = 1 AND Device 2 in powered up D0 stateAND MSRb1 = 1AND →Additional qualification within IGD decode (comprehends MDA requirements)Mem AccessGR06(3:2)A0000h–AFFFFh B0000h–B7FFFh B8000h–BFFFFh00 IGD IGD IGD01 IGD1011PCI-to-PCI Bridge orHub InterfacePCI-to-PCI Bridge orHub InterfaceELSE VGA Mem space legacy decode:IF Device 1 Mem_Access_En = 1.PCI-to-PCI Bridge orHub InterfaceIGDPCI-to-PCI Bridge orHub InterfacePCI-to-PCI Bridge orHub InterfacePCI-to-PCI Bridge orHub InterfaceIGDVGA Mem RangeMDA Mem RangexA0000h – xBFFFFhxB0000h – xB7FFFhVGA_en MDAP Range Destination Exceptions/Notes0 0 VGA, MDA Hub Interface0 1 Illegal Illegal Illegal1 0 VGA, MDA AGP1 1 VGA, MDA AGP, Hub Interface66 Intel ® 82865G/82865GV GMCH Datasheet