i.MX ProcessorsのトピックAndroid 4.4.3 spdif out not working

Android 4.4.3 spdif out not working

marcobologna — Thu, 29 Sep 2016 09:16:49 GMT

I use android 4.4.3 and I would like use the Spidif out.

In ALSA device list imx-spdif is listed as audio card 1

I configured the /hardware/imx/alsa/config_spdif.h as out, after

I tried by console tinyplay /test.wav -D 1 -d 0.

I check by oscilloscope the out and it works, but I not listen sound.

It seems mute audio.

I tried by console tinyplay also with sgtl5000 and HDMI and sound is ok.

How can I check?

The Android 4.4.3 can transmit the spdif audio?

I not have error or warning in all logs, but I not have out sound.

Thanks in advance for any help.

Re: Android 4.4.3 spdif out not working

igorpadykov — Fri, 30 Sep 2016 11:33:24 GMT

Hi Marco

one can test with linux, please check sect.32.2 S/PDIF Tx Driver attached

Linux Manual, use nxp Linux 3.10.53 bsp

http://www.nxp.com/webapp/Download?colCode=L3.10.53_1.1.0_iMX6QDLS_Bundle&appType=license&location=null&Parent_nodeId=13…

Best regards
igor
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Re: Android 4.4.3 spdif out not working

marcobologna — Fri, 30 Sep 2016 17:42:38 GMT

The problem was solved!!!!

The bit SCR_VAL_CLEAR to register SPDIF_SCR and is mask must be set to work..

The "validity" flag (bit 28 in each subframe, counting from preamble bit 0) was going out as 1 rather than 0, and per SP-DIF standard '1' denotes an *invalid* sample, like from a scratched CD giving read errors (though it's reversed again in i.MX6 SPDIF_SCR register, where the power-on default '0' in bit 5 means "send out 1s").

/kernel_imx/sound/soc/fsl/fsl_spdif.c

if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
   scr = SCR_TXFIFO_AUTOSYNC | SCR_TXFIFO_CTRL_NORMAL |
   SCR_TXSEL_NORMAL | SCR_USRC_SEL_CHIP |
-   SCR_TXFIFO_FSEL_IF8;

+   SCR_TXFIFO_FSEL_MASK | SCR_VAL_MASK;

   for (i = 0; i < SPDIF_TXRATE_MAX; i++)
   clk_prepare_enable(spdif_priv->txclk[i]);

}