Example System Power States (Windows CE .NET 4.2)

Microsoft Windows CE .NET 4.2

Example System Power States

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

This 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 NDIS miniports, which are set to D4

When the system enters the Suspend state using this sample configuration, all possible wake sources are enabled with the exception of NDIS miniports. If a device does not support D3, it should automatically enter D4 instead.

Applications can create device power requirements by using >SetPowerRequirement. You can create additional device power requirements by using Power Manager Control Panel application.

See Also