Allow wake timers Windows 7/Vista

Question

I need to allow WakeTimers (computer wake up from sleep/hibernation) for all power plans set on plugged in to Enabled.

Answer 1

From https://adameyob.com/2015/02/how-to-enable-wake-timers/#comment-17

powercfg /SETACINDEXVALUE SCHEME_BALANCED SUB_SLEEP RTCWake 1
powercfg /SETACINDEXVALUE SCHEME_MIN SUB_SLEEP RTCWake 1
powercfg /SETACINDEXVALUE SCHEME_MAX SUB_SLEEP RTCWake 1

Or from http://adameyob.com/2015/02/how-to-enable-wake-timers/#comment-31

FOR /f “tokens=1,2,3,4” %%I IN (‘powercfg.exe /getactivescheme’) DO ( SET GUID=%%L )
powercfg /setacvalueindex %GUID% SUB_SLEEP RTCWAKE 1

Answer 2

It appears that you can use WMI to change the setting.

http://www.daniweb.com/software-development/csharp/threads/272577

Microsoft has a WMI code creator that will help you out:

https://www.microsoft.com/download/en/confirmation.aspx?displayLang=en&id=8572

You will want to search under "root\CIMV2\power" for the power management stuff.

Answer 3

I suspect you can do this using API calls to powrprof.dll, as well as WMI, but I haven't had the time to figure that approach out.

This setting appears to be simply a boolean registry key that is located according to your current power plan:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\User\PowerSchemes\(Current Power Scheme GUID)\(Sleep Category GUID)\(Enable AC or DC Wake Timers GUID) = 0 or 1

Rather than manipulating the registry directly a cleaner approach would be to enable these settings using powercfg.exe.

For AC power:

powercfg.exe -SETACVALUEINDEX SCHEME_CURRENT SUB_SLEEP bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d 1

For Batteries:

powercfg.exe -SETDCVALUEINDEX SCHEME_CURRENT SUB_SLEEP bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d 1

EDIT:

This enables wake timers on my system when running on AC power using High Performance power scheme (purely as a proof of concept):

[DllImport("powrprof.dll", EntryPoint = "PowerWriteACValueIndex", CharSet = CharSet.Auto, SetLastError = true)]
public static extern uint PowerWriteACValueIndex(IntPtr RootPowerKey, ref Guid SchemeGuid, ref Guid SubGroupOfPowerSettingsGuid, ref Guid PowerSettingGuid, uint AcValueIndex);

public static void EnableWakeTimers()
{
    Guid Root = new Guid("8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c"); // High Performance GUID
    Guid Sleep = new Guid("238c9fa8-0aad-41ed-83f4-97be242c8f20"); // Sleep Subcategory GUID
    Guid WakeTimers = new Guid("bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d"); // Wake Timers GUID

    PowerWriteACValueIndex(IntPtr.Zero, ref Root, ref Sleep, ref WakeTimers, 1);
}

This reference is your friend: http://msdn.microsoft.com/en-us/library/aa373163%28v=vs.85%29.aspx

Answer 4

I wrote this powershell script to Enable or Disable wake timers on all current power schemes. On the second last line "POWERCFG -setacvalueindex $xAll $xSubGuid $zz 1" - the 1 means enable. Just change this to 0 to disable.

CLS
#Capture Current Active Power Scheme
$orgScheme = POWERCFG -GETACTIVESCHEME  
$yOrg = $orgScheme -split "\s+"
$xOrg = $yOrg[3]
Write-host Original Scheme = $xOrg
Echo __________________________________
Echo " "

$allScheme = POWERCFG /L
#Echo $allScheme

foreach ($line in $allScheme)
  {
  if ($line.Length -gt 40)
        {
        if ($line.substring(0,5) -eq "Power")
            {
            $yAll = $line -split "\s+"
            $xAll = $yAll[3]
            write-host $xAll
            Powercfg -S $xAll

            $pScheme = POWERCFG /Q
            foreach ($line in $pScheme)
                {
                $yy = $line -split "\s+"
                $xx = $yy[5]+$yy[6]+$yy[7]+$yy[8]
                $zz = $yy[4]
                $xSubGroup = $yy[1]

                If($xSubGroup -eq "SubGroup")
                    {
                    $xSubGuid = $yy[3]
                    }

                If($xx -eq "(allowwaketimers)")
                     {
                      write-host Power Scheme Guid = $xAll
                      write-host Subgroup Guid = $xSubGuid
                      write-host WakeUp Guid = $zz
                      Write-host POWERCFG -setacvalueindex $x $xSubGuid $zz 1
                      Echo " "
                      break
                     }
                }
            POWERCFG -setacvalueindex $xAll $xSubGuid $zz 1
            }
        }
  }
Powercfg -S $xOrg

Enjoy.