Inverted Call In KMDF

NTDEV
1

Hi All,
Is there any sample in KMDF in which inverted call mechanism has been implmented.
If not then can any one throw some light on how to implment inverted call mechanism in KMDF.

I am basically facing problem because in KMDF we deal with WDFREQUEST and not the IRP.

Regards

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2

There is really nothing for you to do, KMDF always pends the request before giving you the WDFREQUEST. In your queue dispatch routine you can set a completion routine or put it into a manual queue if you want kmdf to handle the cancelation semantics for you.

d

From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of nayan kumar
Sent: Monday, April 07, 2008 10:07 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Inverted Call In KMDF

Hi All,
Is there any sample in KMDF in which inverted call mechanism has been implmented.
If not then can any one throw some light on how to implment inverted call mechanism in KMDF.

I am basically facing problem because in KMDF we deal with WDFREQUEST and not the IRP.

Regards

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3

Not to split hairs here, but is this strictly correct?

I’m fairly sure that KMDF alway returns STATUS_PENDING, so in that sense I you’re right…

But IF there’s no Execution Level constraint and the effective Synch Scope is NONE and the request is coming from a user-mode thread… isn’t (as a matter of implementation and not specified architecture) the request actually completed in the context of the requesting thread?? So, it really wouldn’t be pended in that case.

I’m trying to make sure (a) I don’t harbor a mis-understand of how things work, and (b) the archives are correct for “future generations” :slight_smile:

Peter
OSR

4

I guess I make a distinction between marking the request as pending and presentation context. The irp is always marked as pending. If the queue type and state are correct, the request will be presented in the context in which it was initiated. As an example of when this does not occur are
o a queue which is in the stopped state
o a power managed queue and the device is powered down

d

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@osr.com
Sent: Tuesday, April 08, 2008 12:42 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] Inverted Call In KMDF

Not to split hairs here, but is this strictly correct?

I’m fairly sure that KMDF alway returns STATUS_PENDING, so in that sense I you’re right…

But IF there’s no Execution Level constraint and the effective Synch Scope is NONE and the request is coming from a user-mode thread… isn’t (as a matter of implementation and not specified architecture) the request actually completed in the context of the requesting thread?? So, it really wouldn’t be pended in that case.

I’m trying to make sure (a) I don’t harbor a mis-understand of how things work, and (b) the archives are correct for “future generations” :slight_smile:

Peter
OSR

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

5

Thanks, Doron… Just wanted to make sure I didn’t misunderstand.

Peter
OSR