Re: [PATCH v2 0/4] ASoC: qcom: display port changes

From: Srinivas Kandagatla
Date: Tue Apr 23 2024 - 12:00:08 EST




On 23/04/2024 15:58, Johan Hovold wrote:
It is absolutely possible to run all the streams in parallel from the
Audio hardware and DSP point of view.

One thing to note is, On Qualcomm DP IP, we can not read/write registers
if the DP port is not connected, which means that we can not send data
in such cases.

This makes it challenging to work with sound-servers like pipewire or
pulseaudio as they tend to send silence data at very early stages in the
full system boot up, ignoring state of the Jack events.
This bit sounds like it can and should be worked around by the driver to
avoid hard-coding policy which would prevent use cases such as the ones
mentioned above.
This is not simple as you say. We have to fit these into a proper DPCM.
Either we have a dummy Backend connected for each of these pcm sub-devices when DP port is not connected and then switch back to DP when its connected.

Or somehow find a way to not let the pipewire talk to devices which are not connected.


thanks,
srini