PulseAudio has no sound, only has Dummy Output

I'm logged in Ubuntu 20.04 as a root user. I've installed pavucontrol and alsa. And my computer(version:Lenovo G510) is on dual-boot of Windows10 and Ubuntu.

And in Configuration tab's Build-in Audio of pavucontrol , the Profile shows options below:

Digital Stereo (HDMI 5) Output (unplugged) (unavaliable)
Digital Stereo (HDMI 4) Output (unplugged) (unavaliable)
Digital Stereo (HDMI 3) Output (unplugged) (unavaliable)
Digital Stereo (HDMI 2) Output (unplugged) (unavaliable)
Digital Surround 7.1 (HDMI 5) Output (unplugged) (unavaliable)
Digital Surround 7.1 (HDMI 4) Output (unplugged) (unavaliable)
Digital Surround 7.1 (HDMI 3) Output (unplugged) (unavaliable)
Digital Surround 7.1 (HDMI 2) Output (unplugged) (unavaliable)
Digital Surround 5.1 (HDMI 5) Output (unplugged) (unavaliable)
Digital Surround 5.1 (HDMI 4) Output (unplugged) (unavaliable)
Digital Surround 5.1 (HDMI 3) Output (unplugged) (unavaliable)
Digital Surround 5.1 (HDMI 2) Output (unplugged) (unavaliable)
Off

And the Output Devices only show Dummy Output.

Some Info:

uname -sr
Linux 5.11.1-051101-generic

# lspci -vvv | grep -A8 Audio
00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06)
    Subsystem: Lenovo Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller
    Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
    Latency: 0, Cache Line Size: 64 bytes
    Interrupt: pin A routed to IRQ 34
    Region 0: Memory at b9610000 (64-bit, non-prefetchable) [size=16K]
    Capabilities: [50] Power Management version 2
        Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
        Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
--
00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 05)
    Subsystem: Lenovo 8 Series/C220 Series Chipset High Definition Audio Controller
    Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
    Latency: 0, Cache Line Size: 64 bytes
    Interrupt: pin A routed to IRQ 33
    Region 0: Memory at b9614000 (64-bit, non-prefetchable) [size=16K]
    Capabilities: [50] Power Management version 2
        Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
        Status: D3 NoSoftRst- PME-Enable+ DSel=0 DScale=0 PME-

aplay -l 
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 9: HDMI 3 [HDMI 3]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 10: HDMI 4 [HDMI 4]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 0: CX20757 Analog [CX20757 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

And you may ask questions below:

Is it muted? --No

Does the sound icon appear? --Yes, and I can still manipulate the audio, but obviously nothing happens

Have you tried opening alsa mixer and unmuting everything? --yes

I've tried tips below(link here):

1. Simply restart PulseAudio, using this command:pulseaudio -k;

2. Check out to see if the snd_hda_intel kernel module is in use.

   lsmod | grep snd_hda_intel
   

   And it showed that snd_hda_intel was in use.

   Then I added options snd-hda-intel model=generic at the end of the /etc/modprobe.d/alsa-base.conf file and reboot.It doesn't work.

3. Set the model to auto instead of generic in /etc/modprobe.d/alsa-base.conf file.

4. Edit /etc/modprobe.d/alsa-base.conf as root and add options snd-hda-intel dmic_detect=0 at the end of this file. Edit /etc/modprobe.d/blacklist.conf as root and add blacklist snd_soc_skl at the end of the file.Then reboot.The Profile options on Configuration were still the same.

5. Reinstall pulseaudio.

6. Use pacmd like below(link here):

   >>> set-cart-profile 1 output:analog-stereo+input:analog-stereo
   No card found by this name or index.
   >>> set-sink-port 0 analog-output-headphones
   Failed to set sink port to 'analog-output-headphones'.
   

7. Run below commands:(link here)

   pulseaudio --check
   pulseaudio -D
   

8. Delete ~/.config/pulse followed by a reboot.

9. Run below Commands:

   sudo apt-get update
   sudo apt-get upgrade
   sudo apt-get remove --purge alsa-base pulseaudio
   sudo apt-get install alsa-base pulseaudio pavucontrol
   sudo alsa force-reload
   reboot
   
   sudo add-apt-repository ppa:mikhailnov/pulseeffects
   sudo apt-get update
   sudo apt-get install pulseeffects
   

10. Run this command(link here): pulseaudio -k && sudo alsa force-reload But pulseaudio stuck on "Establishing connection to pulseaudio.Please wait."

After tried these tips, the system still got no sound.

I have the same problem on my new intel NUC. These people have the same problem with their Dell XPS.

https://bugs.launchpad.net/ubuntu/hirsute/+source/linux/+bug/1935850

The solution was to rebuild the kernel with the patch suggested in the thread. A much easier solution (but not necessarily better) is to wait until your regular updates include the patch. The patch is in the log for the next kernel cycle -35 acording to the thread.

By default, the sound output is HDMI, not the built-in speakers. So we can't find the built-in speaker setting in the system.

Open the terminal and check the alsamixer status using the following command.

alsamixer

If the default in alsamixer is HDMI or other audio output settings, please continue reading below to see how you can fix it.

What we need to do now is to force Ubuntu to use the analog output by default instead of the HDMI interface, and here we need some information. Open a terminal and enter the following command.

aplay -l

The terminal will list the device, card number, etc. Write down the card number and the analog output device number. My output looks like this:

*** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 9: HDMI 3 [HDMI 3]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 10: HDMI 4 [HDMI 4]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 0: CX20757 Analog [CX20757 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

To modify the configuration file.

sudo gedit /etc/asound.conf

The above command will also open the file. Of course, add the following lines with your card and device number replacements.

defaults.pcm.card 1
defaults.pcm.device 0

Save the file and restart your computer, and you will hear the sound.

It is worth noting that the fix for this problem is available for all Linux distributions such as Linux Mint, Elementary OS, Fedora, Arch Linux, etc. Of course, this "no sound fix" is only available when HDMI is the default setting.

You may check your kernel modules using this command:

modprobe --show-depends snd_hda_intel

If it returns error like this:

modprobe: FATAL: Module snd_hda_intel not found in directory /lib/modules/...

This is due to the missing linux-modules-extra when you update your kernel. To fix this, you have to manually install linux-modules-extra for your kernel.

Run this command to install it:

sudo apt install linux-modules-extra-$(uname -r)

Then restart your computer.

In my experience, you may encounter this again when you update the kernel during apt upgrade.

I found my issue is with gcp kernel I'm using. So, I changed my kernel to generic and this problem never happen again on my computer.

There is other suggestions to install linux-generic meta package which include modules, modules-extra, headers etc. for your kernel.

This package may be missing if you manually removed some kernel packages.

To fix issues with missing kernel packages run in a terminal:

sudo apt install linux-generic

Does this fix your problem?

Edit: After you have restart your computer, you can find that there is no more Dummy Output on your Sound Settings and you can now set which Output Device is suitable for your system.

Sound Settings Screenshot