[alsa-devel] USB audio2.0 status interrupt endpoint

[Clemens Ladisch]

Puneet Sharma wrote:
> As per my understanding, when the above interrupt endpoint is transferred
> to host in response to Interrupt IN request, the host should send me a GET
> CUR volume class-specific request to further qualify the cause of interrupt.
>
> However, I am not getting any class-specific request from host in response
> to the status interrupt transferred to host.
>
> My query is do i need to implement a mixer interface in the uac2 kernel
> driver to get the request or i am doing something wrong in the process.

You must not send a notification for a unit ID that does not exist, so
you must implement the mixer interface.

And you will get a request to read the control's current volume only if
some application that cares about the value (e.g., alsamixer) actually
happens to be running on the host.


Regards,
Clemens