Unattended mode support on Windows Mobile 6.5 devices

Question

Is Unattended mode supported on Windows Mobile 6.5 devices?

Facts

Microsoft advises to enter WM device into unattended mode by using the following API: PowerPolicyNotify(PPN_UNATTENDEDMODE,1) This API does not work on Zebra Mobile Terminals due to different implementation. This platform is looking for running process; otherwise it will switched to suspend state after a time out as it identified in the device power manager menu.

Answer

PowerPolicyNotify(PPN_UNATTENDEDMODE, 1) API is not sufficient on MPA 3.0 based devices, due to different implementation.
The platform is looking for running process; otherwise it will switched to suspend state after a time out as it identified in the device power manager menu.

To stay in unattended mode, user application must keep running process in the background i.e.  call SystemIdleTimerReset() API right after calling PowerPolicyNotify() API.
This API will keep the device in current state i.e. unattended mode as long as it’s running.
In some cases it doesn't run process in background. Hence the device enters into suspend after a timeout as it identify it in its power manager.

A general solution is to call SetSystemTime() API every 20 seconds.

Add the following lines:

• In declaration: static long dwStep = 0;
• In implementation:

LRESULT CALLBACK WndProc(HWND hWnd, UINT uiMsg, WPARAM wParam, LPARAM lParam)

{
      switch(uiMsg)
            …
            …
      case WM_TIMER:
            dwStep++;
            if((dwStep % 15) == 0)
                 SystemIdleTimerReset();
      …
      …
      return 0;
}

 
Note:
This Knowledge base article provides information for application developers about the “Unattended Mode” system power states from Microsoft that are supported in Zebra Mobile Computers.

Microsoft supports the following system power states:

Note:
P stands for state applicable to Pocket PCs, while
S stands for state applicable to Smartphones