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

Srinivas Kandagatla
2024-04-23T15:59:59Z

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