Re: WINCE Power management

Since USB HCD drivers provided by MS (OHCI, UHCI, EHCI) are not power
manager-aware (actually the IOCTL handlers are actually stubs) I suppose you
have cloned the code and added power management handling; did you add the
registry entry GUID to tell PM that your driver supports power management?
Are you returning the correct DeviceDx flags in POWER_CAPABILITIES struct
passed with IOCTL_POWER_CAPABILITIES? Are you sure that you're not blocking
in the first call to IOCTL_POWER_SET?
About DevicePowerNotify remember that the request might not result in a
device power state update. This depends on constraints imposed on Power
Manager by applications, as well as the system power state configuration.
If you enable debug zones in PM.dll you'll get a lot of informations which
can lead you to the problem solution


Luca Calligaris

"Kiran K P" <Kiran K P@xxxxxxxxxxxxxxxxxxxxxxxxx> ha scritto nel messaggio
I have implemented the power management for USB HCD driver.
I have implemented the IOCTL_POWER_CAPABILITIES, IOCTL_POWER_GET and the
IOCTL_POWER_SET in the driver.
When I start the system the device is enumerating through the
and also i am returning true from the IOCTL_POWER_CAPABILITIES when
success.My problem is ... I am not able to call the IOCTL_POWER_SET from
application always.
I have used the SetDevicePower API from an application and the call
succeeded to my IOCTL_POWER_SET once. But the next time onwards I am not
getting a call to my IOCTL_POWER_SET portion in the driver. I tried using
DevicePowerNotify also. These APIs return 0(SUCCESS) but i am not getting
call in the driver. COuld any body please help me on this?
Please let me know how to pass call to the IOCTL_POWER_SET from the
application successfully when ever needed