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Re: PerformDeviceConfigurationChange sequence
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Re: PerformDeviceConfigurationChange sequence


  • Subject: Re: PerformDeviceConfigurationChange sequence
  • From: Jeff Moore <email@hidden>
  • Date: Fri, 28 Feb 2014 10:52:55 -0800

I was referring to what the driver is doing inside its implementation of the PerformDeviceConfigurationChange method. If the driver is dispatching that work asynchronously to another thread and simply returning from the call to PerformDeviceConfigurationChange, it will get the behavior you describe.

--

Jeff Moore
Core Audio
Apple


On Feb 28, 2014, at 10:21 AM, Ploytec <email@hidden> wrote:

Hi Jeff,

Thanks for the reply.
I'm not sure I understand your suggestion.

28/02/2014 15:55:03,228 coreaudiod[511]: +PerformDeviceConfigurationChange
28/02/2014 15:55:03,228 coreaudiod[511]: +StartIO
28/02/2014 15:55:03,987 coreaudiod[511]: -PerformDeviceConfigurationChange
28/02/2014 15:55:04,013 coreaudiod[511]: -StartIO

shows that the driver returns from PerformDeviceConfigurationChange at 03,987. 
I use 
           AudioObjectID theDeviceObjectID = GetObjectID();
            CADispatchQueue::GetGlobalSerialQueue().Dispatch(false, ^{
                PtASPlugInPlugIn::Host_RequestDeviceConfigurationChange(theDeviceObjectID, myChangeAction, &mConfigChangeInfo);
            });

to request the change.

Eric Gorouben
Le 28 févr. 2014 à 19:08, Jeff Moore <email@hidden> a écrit :

The HAL stops IO, calls PerformDeviceConfigurationChange() and then restarts IO all in a series on the same thread (actually, from the same function in HAL’s implementation to be precise). So it seems like the only way you could get the behavior you are describing is if your driver returns from PerformDeviceConfigurationChange() before the change has actually completed. Could this be the case here?

--

Jeff Moore
Core Audio
Apple

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References: 
 >PerformDeviceConfigurationChange sequence (From: Ploytec <email@hidden>)
 >Re: PerformDeviceConfigurationChange sequence (From: Jeff Moore <email@hidden>)
 >Re: PerformDeviceConfigurationChange sequence (From: Ploytec <email@hidden>)

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