AVStream Power Management

NTDEV
1

Hi All,

I have a question for you about two callback functions of KSDEVICE_DISPATCH. There are SetPower and QueryPower. Do I need to handle these two functions when I implement selective suspend in my AVStream driver ? The problem I encounted is my device cannot be waken up after it eneters selective suspend under Vista OS, but it works properly under XP SP2 OS. Basically I didn’t does anything complicated like what generic WDM drivr did when it receive IRP_MN_SET_POWER, and IRP_MN_Query_POWER. Do I need to? What will cause my power IRP ( Wake up my device to D0) hanged?

2

Since AVStream/KS is the power policy owner, you cannot actually get
selective suspend to work reliably. On the power policy owner can
request irps and maintain the power state of the device, if you as the
miniport start requesting power irps, you are putting ks/avstream into
an undefined/untested state.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of
adroit@ms4.hinet.net
Sent: Thursday, May 03, 2007 6:19 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] AVStream Power Management

Hi All,

I have a question for you about two callback functions of
KSDEVICE_DISPATCH. There are SetPower and QueryPower. Do I need to
handle these two functions when I implement selective suspend in my
AVStream driver ? The problem I encounted is my device cannot be waken
up after it eneters selective suspend under Vista OS, but it works
properly under XP SP2 OS. Basically I didn’t does anything complicated
like what generic WDM drivr did when it receive IRP_MN_SET_POWER, and
IRP_MN_Query_POWER. Do I need to? What will cause my power IRP ( Wake up
my device to D0) hanged?

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

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

3

Dear Doron,

Thank you very much for your reply. By the way, I would like to know if my AVStream mini driver ( for WebCam ) has a chance to support selective suspend by setting a registry key like PowerDownWhenUnopened which works properly with my stream class mini driver ( also for WebCam ). This key seems not work with AVStream mini dirver.

4

I don’t know, but PowerDownWhenUnopened is not the same as selective
suspend. Selective suspend is geared towards arming your device to wake
itself up, PowerDownWhenUnopened just turns the device off and does not
arm for wake.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of
adroit@ms4.hinet.net
Sent: Thursday, May 03, 2007 11:44 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] AVStream Power Management

Dear Doron,

Thank you very much for your reply. By the way, I would like to know if
my AVStream mini driver ( for WebCam ) has a chance to support selective
suspend by setting a registry key like PowerDownWhenUnopened which works
properly with my stream class mini driver ( also for WebCam ). This key
seems not work with AVStream mini dirver.

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

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer