[wdmaudiodev] Vista improperly shows names from MediaCategories

  • From: Eugene Muzychenko <emuzychenko@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Thu, 17 Apr 2008 10:14:23 +0700

I have developed a customizable WDM audio miniport driver based on
portcls. Driver customization consists of selecting driver/device
names and some other parameters, such as topology node names/GUIDs in

To maintain MediaCategories, I use unique GUID set:
xxxxxxxx-xxxx-11db-bc7a-00001b40b067. First two parts are unique for
each driver configuration and each topology node. When driver is installed, it
creates entries in MediaCategories for each topology node. When driver
is uninstalled, it deletes these entries.

When I tested two different configurations installed together, they
worked fine. I checked GUID created, and there were no errors. First
driver configuration created "Line 1" and "Line 2" entries for capture
and render categories (both KSNODETYPE_LINE_CONNECTOR types) and
second driver configuration creates "Mixout 1" and "Mixout 2" entries.

While both drivers are installed simultaneously, all nodes and
endpoints are visible with their correct names. But when I uninstalled
first driver configuration (which uses "Line N" names), I see "Mixout
1" and "Line 2" endpoints. Opening the "Line 2" device properties in
the Sound panel, I see "Line 2" at General tab and "Mixout 2" at
Levels tab.

I checked MediaCategories branch, and there was no entry named "Line
1" or "Line 2". There was only proper GUIDs created by second driver
configuration with "Mixout N" names. Second driver module has no
"Line" substring at all so it cannot erratically generate a wrong

When I restarted AudioEndpointBuilder service, the names became
correct. I'm afraid AudioEndpointBuilder either has a kind of hash, keeping
hashed values instead of GUIDs, or compares not all GUID bytes. It is
the only possible explanation :(

Microsoft guys, could you please comment this issue? If needed, I can
place a bug report at Microsoft site.

I use Vista SP1 Ultimate English 32-bit.



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