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 PMSubject: [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. HWMake 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 panelIn 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
****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/
