6

I had mpd/mpc running on my Ubuntu 12.04.3 LTS headless, X-less server. I decided to switch out the songs; I moved the old songs out of the /Music directory, moved the new songs in, and ran mpc update, but it failed to resume playing.

Naturally, I started changing things, according to what I could find on Google, but nothing seems to work.

When I run mpc commands, like mpc status, I get the error message Failed to read mixer for 'My ALSA Device': no such mixer control: PCM.

I can play music when I use the command sudo aplay piano.wav, and similar commands.

Here's some diagnostic info: http://pastebin.com/1CzbeYBC. It contains

  • /etc/mpd.conf
  • aplay -L
  • aplay -l
  • mpd verbose from the command line
  • amixer & amixer contents

I would appreciate any pointers! Thank you.

user220227
  • 101
  • 1
  • 1
  • 6
  • Why sudo? Don't you have access to the device nodes in /dev/snd/? Are you member of the audio group? – CL. Nov 28 '13 at 18:04
  • @CL: mpd runs under the account mpd, but that account doesn't have login privileges, so I use sudo when debugging. My login is not a member of the audio group, but mpd is. /dev/snd/* have crw-rw---T permissions, and belong to the group audio. – user220227 Nov 29 '13 at 19:54
  • I added alsa-info.sh output: http://pastebin.com/2zmWPKv6 – user220227 Nov 29 '13 at 19:55
  • Does amixer set "PCM" 0dB work? If yes, something has changed with the mpd configuration. – CL. Nov 29 '13 at 22:07
  • @CL: amixer set "PCM" 0dB gives me the following output: Simple mixer control 'PCM',0 Capabilities: pvolume pswitch penum Playback channels: Front Left - Front Right Limits: Playback 0 - 31 Mono: Front Left: Playback 23 [74%] [0.00dB] [on] Front Right: Playback 23 [74%] [0.00dB] [on] which is a change from Playback 28 [90%] [7.50dB] – user220227 Nov 30 '13 at 00:20
  • @CL: Continued... I don't know if that's what you meant when you asked if it "worked". Yet aplay still works and mpd still does not. – user220227 Nov 30 '13 at 00:26
  • Yes, that works. If amixer and aplay work, then there is nothing wrong with your ALSA configuration. It is possible that mpd does not have rights you think it has. – CL. Nov 30 '13 at 09:44

3 Answers3

4

@CL was right; alsa was working but mpd was not.

I discovered that if I switched to the home folder of the mpd user (export HOME=/var/log/mpd), the aplay commands (e.g. sudo -u mpd aplay /usr/share/sounds/alsa/Front_Center.wav) would no longer work.

More Googling until I found http://ubuntuforums.org/showthread.php?t=1138454

The solution was sudo apt-get remove pulseaudio. Once that was done, everything was working again.

user220227
  • 101
  • 1
  • 1
  • 6
1

Since your using MPD with pulseaudio, you can change the audio_output accordingly:

sudo nano /etc/mpd.conf

Comment this section:

#audio_output {
#   type       "alsa"
#   name       "My ALSA Device"
#   device      "hw:0,0"    # optional
#   mixer_type      "hardware"      # optional
#   mixer_device    "default"   # optional
#   mixer_control   "PCM"       # optional
#   mixer_index "0"     # optional
#}

Uncomment this

audio_output {
    type        "pulse"
    name        "My Pulse Output"
#   server      "remote_server"     # optional
#   sink        "remote_server_sink"    # optional
}

You may have to add rights on the mpd user too:

sudo adduser mpd pulse
sudo adduser mpd pulse-access

Restart your MPD:

sudo systemctl restart mpd
Sebastien DA ROCHA
  • 181
1

For me the solution was to set mixer_control to "Headphones" as amixer output suggested.

audio_output {
   type          "alsa"
   name          "My ALSA Device"
   mixer_control "Headphones"
}

This is for the Raspberry Pi 1 B.

JPT
  • 369
  • On my Raspberry Pi 1 B+ the correct mixer is "Headphone" without "s" at the end. You can check this with amixer scontrols. – Sethos II Jun 25 '21 at 11:26