Home / ubuntu / Questions / 1119938
Accepted
EC84B4
Asked: 2019-02-21 12:40:35 +0800 CST

Audio volume doesn't change

  • 772

When audio level is at 0 as expected no audio. Is heard but when I increase the volume level the volume is always at loudest possible.

Update: Ubuntu 18.10.

Laptop: asus ux550vd.

speakers laptop's builtin audio.

Audio device: Intel Corporation CM238 HD Audio Controller (rev 31).

00:1f.3 Audio device: Intel Corporation CM238 HD Audio Controller (rev 31)
Subsystem: ASUSTeK Computer Inc. CM238 HD Audio Controller
Flags: bus master, fast devsel, latency 32, IRQ 130
Memory at ed328000 (64-bit, non-prefetchable) [size=16K]
Memory at ed300000 (64-bit, non-prefetchable) [size=64K]
Capabilities: <access denied>
Kernel driver in use: snd_hda_intel
Kernel modules: snd_hda_intel
sound drivers asus 18.10

2 Answers

  1. I had the same issue on my Laptop. (BTW my laptop is thinkpad x1)

    When I checked the alsamixer I noticed that like you said, it was the PCM changes that affect volume and not Master.

    I come upon this solution, and It worked for me.

    In short, find this file:

    /usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf.common

    And add these three lines:

    [Element Master]
switch = mute
volume = ignore

    Directly above of this part of code:

    [Element PCM]
switch = mute
volume = merge
override-map.1 = all
override-map.2 = all-left,all-right

    And Restart.

    • 4
  2. Best Answer

    EDIT: pactl load-module module-alsa-sink control=PCM should result in pulseaudio seeing a new output device that will control the PCM volume. If changing this device allows for proper control of audio output volume, you can add a line load-module module-alsa-sink control=PCM to /etc/pulse/default.pa

    PCM (pulse code modulation) occurs at ALSA kernel level, and is responsible for sampling and conversion of digital signals from software to analog ones heard out of your hardware (PCM Playback channel), as well as analog ones coming in from your microphone (PCM Capture) to their digital form.

    Linux audio output and volume control allows for a lot of versatility, but it can make thinks more complicated and more difficult to troubleshoot as well. For output, the flow is more or less like this:

    START:Application audio you wish to hear produces digital audio data

  > Pulse app and libraries (user control with pavucontrol happens here and changes are then sent to the pulse engine server) 

     > Pulse engine server (the core of Pulseaudio package)  

         >  ALSA Kernel API (alsamixer control, PCM, MIDI and Sequencer API) 

              > ALSA kernel driver processes data to make it understandable to our hardware

END: Speaker output

    I think pactl from pulseaudio package should get you started and on the right track, please try

    $pactl set-sink-volume $(pactl info | grep -i Sink | cut -d ':' -f2) 25%

    and let us know if the audio volume gets set to 1/4 of the range, or again jumps to 100%.

    • 3