Dear all,
We have a usbvideo.sys lower filter driver. Our filter driver will enhance USB selective suspend function(device power state D2).
But I found I cannot change the current power state to D2 or D3, It still display D0, although I know the device power state is D3 (almost 0.06 mA) by using Ampere meter.
How can I change the current power state in driver?
thank you very much.
Jiang
You can’t fix this in your driver. The power state reported in device manager is based on the PDO’s power state and the bus driver calling PoSetPowerState on its pdo. Since this API has no runtime visible side effects outside of the device manager UI, not that many bus drivers get it right (KMDF bus drivers get the correct behavior btw)
d
Sent from my phone with no t9, all spilling mistakes are not intentional.
-----Original Message-----
From: xxxxx@gmail.com
Sent: Monday, July 06, 2009 6:03 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] How to change device manager’s current power sate map
Dear all,
We have a usbvideo.sys lower filter driver. Our filter driver will enhance USB selective suspend function(device power state D2).
But I found I cannot change the current power state to D2 or D3, It still display D0, although I know the device power state is D3 (almost 0.06 mA) by using Ampere meter.
How can I change the current power state in driver?
thank you very much.
Jiang
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thank you Doron Holan
Even if my driver is the function driver in XP, I still cannot change the current power state.
right?
If it’s true, are there any tools can get current power state?
thank again
Sorry, there are no built in apis which give you the last d state irp which flowed through the stack if the bus driver does not call PoSetPowerState appriopriately. You can expose this state through an ioctl to your driver if you want
d
Sent from my phone with no t9, all spilling mistakes are not intentional.
-----Original Message-----
From: xxxxx@gmail.com
Sent: Monday, July 06, 2009 7:19 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] How to change device manager’s current power sate map
thank you Doron Holan
Even if my driver is the function driver in XP, I still cannot change the current power state.
right?
If it’s true, are there any tools can get current power state?
thank again
—
NTDEV is sponsored by OSR
For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars
To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer
thank you Doron