Bastien Nocera wrote:
On Wed, 2016-10-12 at 14:43 +0200, Clemens Ladisch wrote:
Bastien Nocera wrote:
" A change of state in the audio function is most often caused by a certain event that takes place. An event can either be user- initiated or device-initiated. User-initiated jack insertion or removal is a typical example of a user-initiated event. "
There are not many USB Audio 2.0 devices, and I'm not aware of any that actually implements this.
I guess I would see whether there are events if I captured the USB traffic even without special handling/turning on a feature in the drivers, right?
Most devices do not even have the status endpoint (see "lsusb -v"). To check what events arrive, you can add logging to the snd_usb_mixer_interrupt() function.
Regards, Clemens