[wdmaudiodev] Re: Problem writing to endpoint property store using Standard user account on Vista

  • From: "Michael R. Preston" <mike@xxxxxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 18 Oct 2006 10:36:31 -0700

Well, that's only partly correct. The prop page extension is only handed a pointer to the system effects property store. It isn't handed a pointer to the endpoint property store. For example in the Swap APO
sample code, the prop page extension code uses the system effects
property store for the "Enable Channel Swap GFX" and "Enable Channel
Swap LFX" properties, but uses the endpoint property store for the
"Disable System Effects" property. Since the prop page extension isn't
handed a pointer to the endpoint property store, it has to get it from
the MMDevice through the device enumerator.


The call to OpenPropertyStore() fails when trying to open the endpoint property store for writing. This seems to be because when RunDLL32 is called to open the control panel, it's run with the current user's username, not administrator. So even passing the prop page extension a pointer to the endpoint property store might not even help, since it's not running in the proper context. How can we get the control panel to run as administrator when RunDLL32 is called? Otherwise, no prop page extensions that use the endpoint property store will work when running in a Standard user account.

On a related note, I was able to get an external applicaton to write to
the endpoint property store simply by installing the app under the
"Program Files" directory while running in an administrator account.
Apparently, this causes the app to run as administrator even when
running in a Standard user account.

Mike

Larry Osterman wrote:
Signing the APO won't affect your ability to read or write to the
property store.

If you use the IPropertyStore objects handed to your prop page
extension in the sound control panel, you should be able to read and
write properties to that store.


-----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of
mike@xxxxxxxxxxxxxxxxxxx Sent: Wednesday, October 18, 2006 8:35 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: Problem
writing to endpoint property store using Standard user account on
Vista


Larry, Does this have anything to do with the fact that my APO isn't
signed, or just because the app isn't running as administrator?  Like
I said previously, I'm seing the same problem with the property page
extension for the endpoint in the Sound control panel.  Also, is this
just a problem with the endpoint property store and not the system
effects endpoint?

Mike

-----Original Message-----

From:  Larry Osterman <Larry.Osterman@xxxxxxxxxxxxx> Subj:
[wdmaudiodev] Re: Problem writing to endpoint property store using
Standard user account on Vista Date:  Wed Oct 18, 2006 7:01 am Size:
2K To:  "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>

That's correct.  The endpoint property store is machine-wide and only
administrators can modify it.  If you need to modify the endpoint
property store outside the mmsys.cpl framework, you need to run your
applet elevated.


-----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Michael R. Preston Sent: Tuesday, October 17, 2006 10:15 PM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Problem writing to endpoint property store using Standard user account on Vista

I'm seeing a problem writing to the endpoint property store from an application or from a property page extension in the Sound control
panel when running on a Standard user account. When doing an OpenPropertyStore() on the default endpoint's MMDevice with either STGM_READWRITE or STGM_WRITE, the call fails. Opening the property store with STGM_READ still works, though. However, the exact same
code (with STGM_READWRITE specified) works on an administrator
account. Could this be a problem with unsigned drivers or APOs? I
noticed the problem in RC1, and it's still there in RC2. The problem
doesn't happen with the built-in system effects, but does happen with
my custom APO. Anyone have any ideas?


Thanks, Mike -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
Mike Preston | Home/Office: (360)756-1655 | | E-mail:
mike@xxxxxxxxxxxxxxxxxxx | Cell: (360)303-9331 | |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| |
The man who follows the crowd will usually get no | |
further than the crowd. The man who walks alone is | |
likely to find himself in places no one has ever been. | |
-- Alan Ashley-Pitt | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ******************


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-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | Mike Preston | Home/Office: (360)756-1655 | | E-mail: mike@xxxxxxxxxxxxxxxxxxx | Cell: (360)303-9331 | |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| | The man who follows the crowd will usually get no | | further than the crowd. The man who walks alone is | | likely to find himself in places no one has ever been. | | -- Alan Ashley-Pitt | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ******************

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