After I posted the page on Windows Mobile MEssage Queues I decided to use the Power Manager sample in it to diagnose a problem that I have had with my AT&T Tilt since the firmware update. The problem was that after turning the device on many times it would immediatly turn back off. Using the RequestPowerNotifications sample I was able to see what was going on with the power manager when this problem occured. It appears the the device would go into a resuming state and then immediatly go back to the suspended state. Refering back to the article I published on Windows Mobile Power Management I remembered that if the device enters the resuming state and does not switch to another state then the device will suspend itself. The time to change state is usually 15 seconds. But OEMs have the option to change this time. Upon opening the registry path [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\Timeouts] I found the keys [ACResumingFromSuspendTimeout] and [BatteryResumingFromSuspendTimeout] were both set to 1 second. I set them to 5 seconds and I have not seen the problem since then. So it would appear the problem was caused by the new power manager that on the device being unable to change the power state of the device fast enough.
Tags: