I want to check it here. Don’t remember clearly, maybe I read it somewhere:
Can WDF objects(such as wdfdevice\ wdfrequests) be shared beteen WDF drivers? It’s not a hard job to translate a object handle beteen drivers. But I think there are hierarchy relations beteen objects in a driver, such as driver object is the root object for all other objects. So I doubt it will result in confusion if a handle from other driver is used.
I searched. But forget where or if I read such a content. Any issues is appriciated.
2010-08-23
> Can WDF objects(such as wdfdevice\ wdfrequests) be shared beteen WDF drivers?
No.
It’s not a hard job to translate a object handle beteen drivers
What particular object do you want to share?
–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com
You caanot share wdf handles between drivers. What are you trying to do?
d
dent from a phpne with no keynoard
-----Original Message-----
From: changpei1982
Sent: August 23, 2010 1:27 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] WDF object between drivers
I want to check it here. Don’t remember clearly, maybe I read it somewhere:
Can WDF objects(such as wdfdevice\ wdfrequests) be shared beteen WDF drivers? It’s not a hard job to translate a object handle beteen drivers. But I think there are hierarchy relations beteen objects in a driver, such as driver object is the root object for all other objects. So I doubt it will result in confusion if a handle from other driver is used.
I searched. But forget where or if I read such a content. Any issues is appriciated.
2010-08-23
—
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@Dorn
Thanks! I’m not try to imply any function. Just want to understand the mechanism of WDF.
I have thought about it and consider that, it’s because that every WDF driver has some private global variable which is used to interpretation wdf handles, so they can’t be shared between drivers. And child wdf handls should be associated with wdf driver object.
I want to confirm, if my above opinion is right?
You caanot share wdf handles between drivers. What are you trying to do?
d
dent from a phpne with no keynoard
-----Original Message-----
From: changpei1982
Sent: August 23, 2010 1:27 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] WDF object between drivers
I want to check it here. Don’t remember clearly, maybe I read it somewhere:
Can WDF objects(such as wdfdevice\ wdfrequests) be shared beteen WDF drivers? It’s not a hard job to translate a object handle beteen drivers. But I think there are hierarchy relations beteen objects in a driver, such as driver object is the root object for all other objects. So I doubt it will result in confusion if a handle from other driver is used.
I searched. But forget where or if I read such a content. Any issues is appriciated.
2010-08-23
—
NTDEV is sponsored by OSR
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http://www.osr.com/seminars
To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer
—
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For our schedule of WDF, WDM, debugging and other seminars visit:
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> I have thought about it and consider that, it’s because that every WDF driver has some private global
variable which is used to interpretation wdf handles
Lots of issues around this, for instance, refcounting/ownership.
The design choice of WDF was to expose no WDF stuff from the driver. For other drivers, it is just another WDM driver. Everything about WDF is just internal details of this driver, nothing else.
–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com
> I have thought about it and consider that, it’s because that every WDF driver has some private global
variable which is used to interpretation wdf handles
Lots of issues around this, for instance, refcounting/ownership.
The design choice of WDF was to expose no WDF stuff from the driver. For other drivers, it is just another WDM driver. Everything about WDF is just internal details of this driver, nothing else.
Yes!
My meaning is that WDF has too much undocument. It’s not helpful for programmers to understand them. I always got blocked when tried to deep in it.
Anyway, Thank!
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What exactly about the undocumented parts of KMDF are blocking you from using it effectively? There is a reason it is undocumented. It is things that you should not take a dependency on because they can (and do!) change
d
-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of changpei1982
Sent: Monday, August 23, 2010 9:04 AM
To: Windows System Software Devs Interest List
Subject: Re: Re:[ntdev] RE: WDF object between drivers
I have thought about it and consider that, it’s because that every WDF
driver has some private global variable which is used to interpretation
wdf handles Lots of issues around this, for instance, refcounting/ownership.
The design choice of WDF was to expose no WDF stuff from the driver. For other drivers, it is just another WDM driver. Everything about WDF is just internal details of this driver, nothing else.
Yes!
My meaning is that WDF has too much undocument. It’s not helpful for programmers to understand them. I always got blocked when tried to deep in it.
Anyway, Thank!
NTDEV is sponsored by OSR
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NTDEV is sponsored by OSR
For our schedule of WDF, WDM, debugging and other seminars visit:
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changpei1982 wrote:
Thanks! I’m not try to imply any function. Just want to understand the mechanism of WDF.
I have thought about it and consider that, it’s because that every WDF driver has some private global variable which is used to interpretation wdf handles, so they can’t be shared between drivers. And child wdf handls should be associated with wdf driver object.
I want to confirm, if my above opinion is right?
Yes. KMDF is essentially a sophisticated wrapper around the native WDM
driver model (hmm, that’s redundant). The things that get passed
between drivers are WDM things, like IRPs. When those things arrive at
a KMDF driver, the KMDF framework (which is also redundant…) wraps
KMDF structures around them. Before they leave your driver, the KMDF
structures are stripped away, and the WDM objects are passed along.
That’s even true when two KMDF drivers communicate directly. The
WDFREQUEST becomes an IRP, the IRP is forwarded, and the second driver
wraps a brand-new WDFREQUEST around it.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
OK, I will back to real world, not get into a dead end on this point.
Thanks Tim your comment is helpful.
I also agree it’s reasonable for KMDF be undocumented, Doron.
changpei1982 wrote:
Thanks! I’m not try to imply any function. Just want to understand the mechanism of WDF.
I have thought about it and consider that, it’s because that every WDF driver has some private global variable which is used to interpretation wdf handles, so they can’t be shared between drivers. And child wdf handls should be associated with wdf driver object.
I want to confirm, if my above opinion is right?
Yes. KMDF is essentially a sophisticated wrapper around the native WDM
driver model (hmm, that’s redundant). The things that get passed
between drivers are WDM things, like IRPs. When those things arrive at
a KMDF driver, the KMDF framework (which is also redundant…) wraps
KMDF structures around them. Before they leave your driver, the KMDF
structures are stripped away, and the WDM objects are passed along.
That’s even true when two KMDF drivers communicate directly. The
WDFREQUEST becomes an IRP, the IRP is forwarded, and the second driver
wraps a brand-new WDFREQUEST around it.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
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chang pei, are you chinese?
If you want to understand more about WDF I’d suggest reading the ‘Developing drivers with the Windows Driver Framework’. I find it invaluable to have all of the most important information about something I’m using in one place ;).
>If you want to understand more about WDF I’d suggest reading the ‘Developing drivers with the Windows Driver >Framework’. I find it invaluable to have all of the most important >information about something I’m using in one place ;).
Thanks Chris.
I agree with you the book is the first choice for studying WDF. In fact, there is few other choices now 
@zhonghong200:
Yes, I’m Chinese. It’s not very offen to see landsman in this maillist
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I am a beginner in wdf,how long you use wdf. chang pei
Uh … why don’t you two take it private?
Gary G. Little
H (952) 223-1349
C (952) 454-4629
xxxxx@comcast.net
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of zhonghong200@163.com
Sent: Tuesday, August 24, 2010 8:01 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] WDF object between drivers
I am a beginner in wdf,how long you use wdf. chang pei
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