Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

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2.3.1.2.System Startup

The Intel® 815 chipset has multiple possible device modes. The selection of which mode will be auto- detected is represented in the following flow chart. The software requirements for implementing this high level flow are detailed in the next section.

Multi-monitor configurations are not addressed, as that is a function of the operating system when supported. System BIOS also provides the ability to select any of the display devices as the primary display device.

Figure 4. Device Mode Auto-Detect Flowchart

System Reset

Memory and Basic

 

 

chipset Initialization

 

 

 

 

 

 

AGP Card

 

Mode 1

 

Yes

(AGP Card)

 

Detected?

 

 

DEV#0, REG53H, Bit1=0

 

 

 

 

No

 

 

 

 

 

Mode 2

 

Display Cache

 

(Internal Graphics with

 

Yes

Display Cache on GPA

 

(GPA Card)

Card)

 

 

 

Detected?

 

DEV#0, REG53H, BIT1=1

 

No

 

Mode 3

 

 

(Internal Graphics with

 

 

 

 

 

No

Shared Memory)

 

 

DEV#0, REG53H, BIT1=1

 

 

 

 

 

 

REG70H, BIT7:6=11 or 10

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Intel 815 manual System Startup, Device Mode Auto-Detect Flowchart