Konzol Posted March 26, 2016 Posted March 26, 2016 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!
Igor Posted March 26, 2016 Posted March 26, 2016 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.
Konzol Posted March 26, 2016 Author Posted March 26, 2016 No problem to build kernel for me. But which kernel version supports ap6210 and SPDIF/i2s 3.4.109 ...and ?
Igor Posted March 26, 2016 Posted March 26, 2016 Just go for Banana PRO -> legacy kernel and you will have all drivers inside ... for banana, we have ap6211 now.
Konzol Posted March 26, 2016 Author Posted March 26, 2016 The latest image - wheezy , kernel : 3.4.110-sun7i , the issue does not solved. Now I'm checking the 3.4.111 kernel...
Igor Posted March 26, 2016 Posted March 26, 2016 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
Konzol Posted March 26, 2016 Author Posted March 26, 2016 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.
Konzol Posted March 27, 2016 Author Posted March 27, 2016 Sorry.I2S ouput works fine, only SPDIF swaps randomly the left right channels.
nikkov Posted March 27, 2016 Posted March 27, 2016 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.
Konzol Posted March 27, 2016 Author Posted March 27, 2016 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...
Konzol Posted March 29, 2016 Author Posted March 29, 2016 Here are some pictures. Every pictures shows when start playing 1Khz sine wave on right channel. Visible the wrong signal at start.
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