svn commit: r359446 - head/sys/dev/sound/usb

[Hans Petter Selasky]

On 2020-03-31 14:35, Alexander Leidinger via freebsd-usb wrote:
> Quoting Hans Petter Selasky <hselasky at freebsd.org> (from Mon, 30 Mar 
> 2020 16:50:33 +0000 (UTC)):
> 
>> Author: hselasky
>> Date: Mon Mar 30 16:50:32 2020
>> New Revision: 359446
>> URL: https://svnweb.freebsd.org/changeset/base/359446
>>
>> Log:
>>   Add support for multiple playback and recording devices per physical 
>> USB audio
>>   device. This requires some structural refactoring inside the driver, 
>> mostly
>>   about converting existing audio channel structures into arrays.
>>
>>   The main audio mixer is provided by the first PCM instance.
>>   The non-first audio instances may only have a software mixer for PCM 
>> playback.
> 
> Have you thought about providing different pcm devices per physical USB 
> audio device for the functionality of dev.pcm.X.Y.vchanformat / 
> vchanrate? Incompatible configs between those devices could be prevented 
> at runtime via setting all the incompatible devices per physical device 
> to return EBUSY or such while one of the group is open / in use. 
> /dev/sndstat could also contain some kind of status to this effect and 
> to which group of pcm devices pcmX belongs.
> 

Hi,

There will be two pcm devices, belonging to the same uaudioX device 
having each their independent sysctl tree. So you get:

/dev/dsp0
/dev/mixer0
/dev/dsp1
/dev/mixer1

mixer1 only controls dsp1, and mixer0 only controls dsp0, while it may 
be the same physical USB audio device.

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--HPS