Example System Power States
A version of this page is also available for
4/8/2010
The following registry settings show a sample system-power-state-to-device-power-state mapping:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\State\On]
"Default"=dword:0; D0
"Flags"=dword:10000; POWER_STATE_ON
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\State\UserIdle]
"Default"=dword:1; D1
"Flags"=dword:0
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\State\SystemIdle]
"Default"=dword:2; D2
"Flags"=dword:0
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\State\Suspend]
"Default"=dword:3; D3
"Flags"=dword:200000; POWER_STATE_SUSPEND; @CESYSGEN IF CE_MODULES_NDIS
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\State\Suspend\{98C5250D-C29A-4985-AE5F-AFE5367E5006}]
"Default"=dword:4; D4
; @CESYSGEN ENDIF CE_MODULES_NDIS
The following table shows the system power state and the device power state mapping according to the previous registry example.
| System power state | Device power state |
|---|---|
On |
D0 |
UserIdle |
D1 |
SystemIdle |
D2 |
Suspend |
D3, except for Network Driver Interface Specification (NDIS) miniports, which are set to D4. |
When the system enters the suspended state using this configuration, all possible wake sources are enabled, with the exception of NDIS miniports. If a device does not support D3, it automatically enters D4 instead.
Applications can create device power requirements by using the SetPowerRequirement function. You can create additional device power requirements by using Power Manager in Control Panel.