Intel® 82854 Graphics Memory Controller Hub (GMCH)

4.11.21PMCS – Power Management Control/Status Register (Device #2)

Address Offset:

D4-D5h

Default Value:

0000h

Access:

 

Read/Write, Read Only

Size:

 

16 bits

 

 

Bit

Description

 

 

15

PME_Status –RO:This bit is 0 to indicate that IGD does not support PME# generation from D3

 

(cold).

 

 

 

 

14:9

Reserved

 

 

 

8

PME_En–RO:This bit is 0 to indicate that PME# assertion from D3 (cold) is disabled.

 

 

 

7:2

Reserved

 

 

 

1:0

PowerState–R/W:This field indicates the current power state of the IGD and can be used to set

 

the IGD into a new power state. If software attempts to Write an unsupported state to this field,

 

Write operation must complete normally on the bus, but the data is discarded and no state change

 

occurs.

 

 

On a transition from D3 to D0 the graphics controller is optionally Reset to initial values.

 

Bits[1:0] Power State

 

00

D0 Default

 

01

D1

 

10

D2 Not Supported

 

11

D3

 

 

 

110

D15343-003

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Intel D15343-003 manual Pmcs Power Management Control/Status Register Device #2, Bits10 Power State