Banana Pi M1+

There is a very strange issue using SPDIF and/or I2S output. ( mpd, alsa,  Armiban 4.4, kernel: 3.4.109-banana )

When starting play a new audio track, the left and right channel random swapping.

Upgrading Alsa mpd does not helps. It looks this is known, a kernel level problem. for example:

 

http://mailman.alsa-project.org/pipermail/alsa-devel/2011-February/037038.html

 

Any suggestion how can I solve this issue?

 

Thanks in advance!

There were two major changes in driver since that kernel, but I don't know if it's related / fixed. If you are in a rush, you will need to build a kernel by yourself.

No problem to build kernel for me. But which kernel version supports ap6210 and SPDIF/i2s 3.4.109 ...and ?

Just go for Banana PRO -> legacy kernel and you will have all drivers inside ... for banana, we have ap6211 now.

The latest image - wheezy , kernel : 3.4.110-sun7i , the issue does not solved. Now I'm checking the 3.4.111 kernel... 

It's not compiled yet, latest patch was added 7 days ago.

 

https://github.com/igorpecovnik/lib/blob/master/patch/kernel/sun7i-default/0028-nikkov-i2s-spdif-2.0.patch

 

Author: https://github.com/nikkov

Installed the new kernel with your patch, the channel  swapping issue is not solved, but it looks like solved the glitch, noise and freeze issue when change the track or seeking in the track.

Sorry.I2S ouput works fine, only SPDIF swaps randomly the left right channels.

In my latest patch fixed issue when change the track or seeking in the track only. I don't use SPDIF and I don't know exists this issue in original linux-sunxi sources or not. I have found swapping channels when recording, but I can't fix it yet.

Hi nikkov!

 

Thank you you answare! I found this issue every tested 3.4.xxx kernel. I think the root of the issue could be very similar  to those experienced OMAP platform. (See my first post!). When I start a streem on SPDIF output randomly swapped the left and right channel. The FIFO does not contains valid audio data, only zero, which cause the channel swapping... I think... 

Here are some pictures. Every pictures shows when start playing 1Khz sine wave on right channel. 

Visible the wrong signal at start.