I have a buildroot repo which builds a Linux operating system using the FriendlyElec v4.4 Linux kernel here :
https://github.com/flatmax/buildroot.rk ... ndcad-v4.4

The operating system sets up a dummy soundcard running on the I2S 0 pins. Unfortunately it appears that the DMA drops input samples of audio randomly.

You can run jackdStart.sh and do networked audio with jaaa on the desktop pc to check the results.

This is a very serious problems, as you can't use the rk3399 chip for quality full duplex audio. Any sample rate greater then 48 kHz drops input audio samples.

I have investigated the issue and it seems to be related to the pl330.c DMA engine.

Is there any way to get help upstream from Rockchip to sort this problem out ?