Alsa configuration ignored with hifiberry+dmix and libreelec 9.0.2

tigre-bleu · October 28, 2019 at 9:13 AM

Hello,

I want to use in parallel Kodi and Squeezelite on the same libreelec RPI3 with an Hifiberry DAC Plus soundcard. I used to do that in the past but my SD card died and now I cannot set it up again.

The problem is that the hifiberry card cannot mux multiple streams. Kodi or Squeezelite takes the card - whichever starts first - and the other cannot play.

It should be possible to configure alsa with dmix plugin. I tried the following in /storage/.config/sound.conf and /storage/.config/asound.conf

:

Code

pcm.hifiberry { 
  type hw card 0 
}

pcm.!default { 
  type plug 
  slave.pcm "dmixer" 
}

pcm.dmixer { 
  type dmix 
  ipc_key 1024 
  slave { 
    pcm "hifiberry" 
    channels 2 
  } 
}

ctl.dmixer { 
  type hw 
  card 0 
}

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But this does not seem to have any effect.

Code

# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

It looks like the config file is completely ignored. I did not find anything useful in the logs, but I am not sure of what to look for.

**Da Flex** · October 28, 2019 at 3:36 PM Official Post

Maybe you forgot to do the DAC settings at config.txt.

tigre-bleu · October 28, 2019 at 3:42 PM

I have that in the config.txt:

Code

# Hifiberry
dtoverlay=hifiberry-dacplus
dtoverlay=i2s-mmap
dtdebug=1

**Da Flex** · October 28, 2019 at 4:55 PM Official Post

config.txt looks OK. At your asound.conf I don't see a bindings parameter inside pcm.dmixer. Check whether you need to add this.

tigre-bleu · October 28, 2019 at 6:37 PM

I tried to add bindings like this but with no success:

Code

pcm.hifiberry { 
  type hw card 0 
}

pcm.!default { 
  type plug 
  slave.pcm "dmixer" 
}

pcm.dmixer { 
  type dmix 
  ipc_key 1024 
  slave { 
    pcm "hifiberry" 
    channels 2 
  } 
  bindings {
    0 0
    1 1
  }
}

ctl.dmixer { 
  type hw 
  card 0 
}

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I do not really know what bindings are used for but I took example in alsa documentation

tigre-bleu · November 10, 2019 at 1:29 PM

I bump this message in case somebody has another tip. So far I did not find a solution...

tigre-bleu · November 17, 2019 at 6:05 PM

Well, I didn't manage to do it with libreelec so I installed a raspbian and made it work right away...

**Da Flex** · November 17, 2019 at 6:59 PM Official Post

Quote from tigre-bleu

Well, I didn't manage to do it with libreelec so I installed a raspbian and made it work right away...

It's a very special hardware config, so don't be surprised that I'm just guessing.

Raspbian could help you to understand, how ALSA handles the I2S device. Maybe you can use the asound.conf for LE, too.

tigre-bleu · November 17, 2019 at 7:20 PM

It's almost the same asound.conf. For me it looked like the asound.conf / sound.conf file was just completely ignored by Libreelec.
I will continue to use libreelec on my "standards" Pis, but will keep raspbian on that precise one.

Gauner · April 20, 2020 at 11:07 AM

Hey,

I'm trying for days something similar:

I want to run squeezelite and kodi in parallel in Libreelec on a Raspberry Pi 3b+, sharing the same hardware output.

As far as I understood, there are two ways to achieve that:

1. both using an alsa dmix output

(that's how You try). My /storage/.config/asound.conf looks very similar to Yours:

Code

pcm.dmixer {
    type dmix
    ipc_key 1024
    slave {
        pcm "hw:1,0"
    }
    bindings {
        0 0
        1 1
    }
}

ctl.dmixer { 
  type hw 
  card 1 
}


pcm.!default { 
  type plug 
  slave.pcm "dmixer" 
}

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Neither aplay -L nor squeezelite -l show the dmixer output. But still squeezelite -o dmixer works!

But I can't get Kodi to also use alsa-dmixer. Any suggestions how to achieve that? Kodi always seems to go on PulseAudio which blocks the alsa hardware device. In xbian it works like described. There I have the dmixer-Alsa-Output in Kodi available and I can play sound on Kodi and squeezelite simultaneously.

2. use pulseaudio

I made an entry in /storage/.config/asound.conf:

Code

pcm.pulse {
type pulse
}

and tried to start squeezelite -o pulse. It complains about the device not being available.

So, any suggestions how to achive that?

I managed to make it work with Kodi and Squeezelite running inside raspbian in the "pulse way". But there Kodi is somehow unstable, so I'd like to go back to LibreElec, which I have been running for years on that Raspberry Pi 3 b+.