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DIGI+ I/O spdif input stuck after a while on raspbian

Darko

July 13, 2022 11:12

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Hello,

After a while (several days) running an application reading a continuous audio stream from the SPDIF input with pulseaudio, the audio stream get stuck (no more data available) and the only way to unblock it is to kill the app and reload the drivers as followed on raspbian OS:

sudo killall alsactl
systemctl --user stop pulseaudio.socket
systemctl --user stop pulseaudio.service
sudo modprobe -r snd_soc_rpi_wm8804_soundcard
sudo modprobe -r  snd_soc_wm8804_i2c
sudo modprobe snd_soc_wm8804_i2c
sudo modprobe snd_soc_rpi_wm8804_soundcard
systemctl --user start pulseaudio.service
systemctl --user start pulseaudio.socket

I would like to detect when I should run this procedure (ie when there is an input stream detected on the hardware but no available stream on pulseaudio), but I do not know how to check at the driver / hardware level if the SPDIF input is seeing a signal.

Any help would be appreciated !

Thanks.

Darko.

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3 comments

• 0
  
  HiFiBerry team July 14, 2022 04:33

  Unfortunately there is no such function in the hardware. You need to know that there is a signal before reading from the SPDIF input. The DAC+DSP can sample data even if there is no incoming data stream, but not the Digi+ I/O.

• 0
  
  Darko July 15, 2022 12:48

  Thanks for the quick answer. So if I understand correctly your answer, if my app read the spdif input while there is no signal, this is expected that the hardware can be stuck in a bad state ?

  In my use case, I continuously read the spdif input from a hdmi audio extractor, but I cannot tell if there is actually a stream running on the HDMI interface.

  Is there a way I can safely (ie no deadlock) use your product in such use case ?

  Thanks.

• 0
  
  HiFiBerry team July 15, 2022 12:49

  No, there is no way. You need to be sure that there are data before reading. The DAC+DSP can sample data even if there is no incoming data stream, but not the Digi+ I/O.