On 8/1/24 03:17, Wesley Cheng wrote:
The QC ADSP is able to support USB playback endpoints, so that the main application processor can be placed into lower CPU power modes. This adds the required AFE port configurations and port start command to start an audio session.
Specifically, the QC ADSP can support all potential endpoints that are exposed by the audio data interface. This includes, feedback endpoints (both implicit and explicit) as well as the isochronous (data) endpoints. The size of audio samples sent per USB frame (microframe) will be adjusted based on information received on the feedback endpoint.
Some pre-requisites are needed before issuing the AFE port start command, such as setting the USB AFE dev_token. This carries information about the available USB SND cards and PCM devices that have been discovered on the USB bus. The dev_token field is used by the audio DSP to notify the USB offload driver of which card and PCM index to enable playback on.
It's just fine if the AFE stuff relies on the 'port' definition/concept, but I don't think it needs to pop-up at the ASoC/USB level.