Article ID: 259742
Article Last Modified on 2/12/2007
APPLIES TO
- Microsoft Windows CE OEM Adaptation Kit 2.0
- Microsoft Windows CE 2.10 Enhancement Pack for Windows CE Embedded Toolkit for Visual C++ 5.0
- Microsoft Windows CE Platform Builder 2.11
- Microsoft Windows CE Platform Builder 2.12
- Microsoft Encarta Reference Suite 2001
This article was previously published under Q259742
SYMPTOMS
A Windows CE device suspends after one minute, even though the Idle timeout registry settings are set to disable idle suspend, or are set to values other than one minute.
CAUSE
Windows CE uses a separate idle timeout, called WakeupPowerOff, when the last suspend-to-power on transition was not the result of user input activity. The default value of this idle timeout is 60 seconds.
RESOLUTION
To properly control idle timeout on a Windows CE device, you must set all three of the idle timeout values to the value that you want to use.
The dword values in the following table belong to the registry branch:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power
| Value Name | Description |
|---|---|
| BattPowerOff | The number of seconds Windows CE waits for user input while on battery power before initiating a suspend. |
| ExtPowerOff | The number of seconds Windows CE waits for user input while on external power before initiating a suspend. |
| WakeupPowerOff | The number of seconds Windows CE waits for user input after an event (such as an alarm) triggers a resume before initiating a suspend, regardless of battery or external power. |
Any or all of these values can be set to zero to disable idle suspends under the associated conditions.
STATUS
This behavior is by design.
MORE INFORMATION
Windows CE automatically suspends the system based on user input activity only. Device activity and internal processing are not monitored for idle. Device drivers are notified of suspend and resume. Applications and device drivers are not able to cancel a suspend once it is initiated. You can use the OEM function SystemIdleTimerReset to reset the timeout counter to prevent or delay a suspend.
NOTE: It is inappropriate to view Windows CE power management functionality as being the same as Advanced Power Management (APM) which is common on x86 based Windows platforms.
REFERENCES
Windows CE Platform Builder Books Online; topic: "Battery Driver"; "XXX_PowerUp"; "XXX_PowerDown"; "SystemIdleTimerReset"
Keywords: kbprb KB259742
