Debugging Power Management code

NTDEV
1

I am debugging code I added to a driver to place a USB device into low
power mode when not in use. THis code is intended to place the device into
the D3 power state and the device in the USB suspend state.

Using a USB analyzer I see that the code does put the device into the
suspend state.

Using the Device Manager Properties page Details tab for this driver to
see the Current Power State for this device, the device “Current Power
State” is D0 and does not change. (I am testing on XP SP2 Checked and Free
Build.)

Is the details tab a reliable indication of the current power state of a
device?

Ed

2

Did you call PoSetPowerState? The device management page uses the PDO
state as the state for the device and IIRC, the usbhub driver on xp sp2
does not call PoSetPowerState leading to this type of issue. I had to
explain this to someone in the test org the other week.

D

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Edward Dekker
Sent: Monday, July 04, 2005 8:26 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Debugging Power Management code

I am debugging code I added to a driver to place a USB device into low
power mode when not in use. THis code is intended to place the device
into
the D3 power state and the device in the USB suspend state.

Using a USB analyzer I see that the code does put the device into the
suspend state.

Using the Device Manager Properties page Details tab for this driver to

see the Current Power State for this device, the device "Current Power

State" is D0 and does not change. (I am testing on XP SP2 Checked and
Free
Build.)

Is the details tab a reliable indication of the current power state of a

device?

Ed

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Yes I call PoSetPowerState. After PoSetPowerState I call PoRequestPowerIrp.

Ed

At 02:26 AM 7/5/2005, Doron Holan wrote:

Did you call PoSetPowerState? The device management page uses the PDO
state as the state for the device and IIRC, the usbhub driver on xp sp2
does not call PoSetPowerState leading to this type of issue. I had to
explain this to someone in the test org the other week.

D

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Edward Dekker
Sent: Monday, July 04, 2005 8:26 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Debugging Power Management code

I am debugging code I added to a driver to place a USB device into low
power mode when not in use. THis code is intended to place the device
into
the D3 power state and the device in the USB suspend state.

Using a USB analyzer I see that the code does put the device into the
suspend state.

Using the Device Manager Properties page Details tab for this driver to

see the Current Power State for this device, the device "Current Power

State" is D0 and does not change. (I am testing on XP SP2 Checked and
Free
Build.)

Is the details tab a reliable indication of the current power state of a

device?

Ed

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

Like I said, device manager’s state is pulled from the PDO’s state, so
if the PDO for you stack does not call PoSetPowerState on itself, device
manager will report the wrong state.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Edward Dekker
Sent: Tuesday, July 05, 2005 12:48 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] Debugging Power Management code

Yes I call PoSetPowerState. After PoSetPowerState I call
PoRequestPowerIrp.

Ed

At 02:26 AM 7/5/2005, Doron Holan wrote:

Did you call PoSetPowerState? The device management page uses the PDO
state as the state for the device and IIRC, the usbhub driver on xp sp2
does not call PoSetPowerState leading to this type of issue. I had to
explain this to someone in the test org the other week.

D

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Edward Dekker
Sent: Monday, July 04, 2005 8:26 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Debugging Power Management code

I am debugging code I added to a driver to place a USB device into low
power mode when not in use. THis code is intended to place the device
into
the D3 power state and the device in the USB suspend state.

Using a USB analyzer I see that the code does put the device into the
suspend state.

Using the Device Manager Properties page Details tab for this driver
to

see the Current Power State for this device, the device "Current
Power

State" is D0 and does not change. (I am testing on XP SP2 Checked and
Free
Build.)

Is the details tab a reliable indication of the current power state of
a

device?

Ed

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag argument:
‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com