[wdmaudiodev] =?gb2312?B?tPC4tDogW3dkbWF1ZGlvZGV2XSBSZTogUHJvYmxlbXMgYWJvdXQgZA==? =?gb2312?B?eW5hbWljIGF1ZGlvIHN1YmRldmljZSBvbiBWaXN0YQ==?Date: Fri, 5 Jun 2009 12:46:19 +0800
- From: <StarXing@xxxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
Thanks for your information, Jeff.
I will try it and report later.
Best Regards,
HW
-----邮件原件-----
发件人: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx]
代表 Jeff Pages
发送时间: Friday, June 05, 2009 11:36 AM
收件人: wdmaudiodev@xxxxxxxxxxxxx
主题: [wdmaudiodev] Re: Problems about dynamic audio subdevice on Vista
The ac97 sample is wrong in this respect for Vista. The registering the
topology subdevice MUST be the last thing you do, and unregistering it must be
the first thing. There was a post from one of the Microsoft people some time
back about this. Apparently the audio engine starts building an endpoint when
the topology port is registered, but if the wave subdevice and/or physical
connection isn't present all hell breaks loose.
Jeff
----- Original Message -----
From: StarXing@xxxxxxxxxxxxxx
To: wdmaudiodev@xxxxxxxxxxxxx
Sent: Friday, June 05, 2009 1:22 PM
Subject: [wdmaudiodev] 答复: Re: Problems about dynamic audio subdevice on
Vista
Thanks Jeff.
I follows the WDK ac97 samples to instantiate/uninstantiate the audio
subdevice, and in most cases it works well.
That is:
create wave/topology port/miniport -> register wave/topology subdevice ->
register physical connection when instantiating subdevice and
remove physical connection -> unregister wave/topology subdevcie->release
ports when uninstantiating subdevices.
I doubt whether this is a timing issue.
That is to say, I should wait some for the audio subsystem to prepare the
audio api's well.
Thanks again.
Regards.
HW
Make sure that when a subdevice is instantiated, you create the wave and
topology ports/miniports, register the physical connection, THEN register
the wave subdevice and finally the topology subdevice. Likewise when
removing a subdevice, unregister the topology subdevice first, then the wave
subdevice, the physical connection and finally release the ports. Apparently
if it's not done in that order, a race condition can occur which does what
you're describing.
Jeff
----- Original Message -----
From: StarXing@xxxxxxxxxxxxxx
To: wdmaudiodev@xxxxxxxxxxxxx
Sent: Friday, June 05, 2009 12:49 PM
Subject: [wdmaudiodev] Problems about dynamic audio subdevice on Vista
Hello everyone,
I am develping an audio driver which implement dynamic audio subdevice on
windows vista.
The audio subdevice can be instantiated/uninstantiated on behalf of user's
request through device IO control.
After instantiating the audio subdevice, the user would like to locate thate
audio endpoints through MMDevice API and render through that device.
In most cases these are running without trouble except two strange issues.
1) Can't locate the audio subdevice through MMDevice API although we can see
it in system audio control panel
2) Can't see the audio subdevice in system audio control panel
In case 2, the audio subdevice will appear in system audio control panel if
we restart the "Windows Audio Endpoint Builder" services.
Any pointers on these 2 issues are greatly appreciated.
Thanks and regards,
HW
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Other related posts:
- » [wdmaudiodev] =?gb2312?B?tPC4tDogW3dkbWF1ZGlvZGV2XSBSZTogUHJvYmxlbXMgYWJvdXQgZA==? =?gb2312?B?eW5hbWljIGF1ZGlvIHN1YmRldmljZSBvbiBWaXN0YQ==?Date: Fri, 5 Jun 2009 12:46:19 +0800 - StarXing
