[alsa-devel] Playback samples at a specific time on Intel HDA

Hello,

I am trying to accomplish synchronized audio playback using ALSA & gPTP, on an Intel SkyLake platform have Intel HDA.

I do understand that, starting with SkyLake platform, there is support for querying link time. But, how do I instruct to play the samples at a given (gPTP) time ? Is this possible ? Can someone please point me to code or doc, relevant to my goal ? In essence, I would like to play the samples at the stroke of a given (gPTP) time.

Also, the ALSA page says ... "The link time can be directly measured if supported in hardware by sample counters or wallclocks (e.g. with HDAudio 24MHz or PTP clock for networked solutions)"

What is the connection between PTP clock and sound card here, are there sound cards that can latch on to a PTP clock on a NIC or what ?

Thanks in advance.

Regards, Rajagopal