Hi,

My name is Thierry Bultel from Iot.bzh, and I am part of the responsible team for the audio framework (aka, 4A) in Automotive Grade Linux.

For the ones interested in the audio architecture in AGL (and the ones that will read my list of questions below), these are useful links to follow:

New AVIRT driver in replacement of SND_ALOOP: https://iot.bzh/download/public/2018/amm-dresden/ALSA_Virtual_Dynamic_Sound_...

4A framework kickstart: https://iot.bzh/download/public/2018/amm-dresden/4a-kickstart-Loic-IoTbzh-Dr...

In AGL, we have used the Alsa framework intensively. I wish I could meet the Alsa team next week in Edimburg but unfortunately I will not be available at that date.

Other colleagues of mine will be there, however.

Here are some points that I would like to be addressed at this meeting:

- ioplug PCMs: There are known issues about potential (effective !) deadlocks when using ioplug PCMs. We have worked around this by setting LIBASOUND_THREAD_SAFE=0 Is there any pending work to avoid doing this and fix the bug ?

- capture dispatching According to the experts, what would be the most effective way to implement a capture dispatcher ? The need is to have several applications listening to the same microphone. Is JACK the most suitable solution (at this time) ? (more precisely, this could behave as a 1to1 switch or 1toN, by duplicating the audio stream). A kernel solution based on AVIRT with routing could easily be done, too.

- Documentation: Is there any pending rework of the documentation for having it a little bit more detailed ? For instance, having a page explaining the roles of period_size and buffer_size, would be great, since it impossible to perform sound playback correctly in an application, without understanding those notions.

- Could something like a dynamic setting of the parameters of the rate converter plugin, become a reality one day ?

- What is you overall mind about the AVIRT driver that we (with Fiberdyne) are developing ?

- Is there a release features roadmap for Alsa (kernel & library) ?

- What is your feeling about PipeWire, which could eventually replace PulseAudio (and seems to also invade the JACK land) ?

Thanks ! Thierry Bultel