Internal Audio Not Working on Ubuntu 20.04 After Restarting

Question

My internal audio and mic stopped working after booting into Windows and then restarting and loading Linux.

• The internal audio works fine in Windows (dual-boot).
• The internal audio works fine via HDMI in Linux.
• The sound card is detected and the audio output is shown in pavucontrol, gnome-control-center, and glava but no sound is actually played.
• Ocassionaly on the first attempt the audio will play for a little less than 1 second and slowly fade out to not playing at all.

I have tried (rebooting after each attempt):

1. Checking volume in alsamixer, pavucontrol, and gnome-control-center (all 100%, no mute).
2. Updating and upgrading everything via apt (already up to date).
   sudo apt update && sudo apt upgrade -y
3. Starting pulseaudio.
   pulseaudio --start
4. Force reloading alsa.
   sudo alsa force-reload
5. Removing pulseaudio config.
   rm -rf ~/.config/pulse/*
6. Reinstalling alsa-base and pulseaudio.
   sudo apt remove purge alsa-base pulsaudio && sudo apt install alsa-base pulsaudio
7. Installing linux-modules-extra for my kernel (already existed so reinstalled)
   sudo apt install --reinstall linux-modules-extra-$(uname -r)

Kernel

$ uname -r
5.11.0-37-generic

Internal Sound Card

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC294 Analog [ALC294 Analog]
  Subdevices: 0/1
  Subdevice #0: subdevice #0

$ lspci | grep -i audio
00:1f.3 Audio device: Intel Corporation Comet Lake PCH cAVS
01:00.1 Audio device: NVIDIA Corporation Device 10fa (rev a1)

Any help would be greatly appreciated. Let me know if you need any more information.

Answer 1

After hours of attempting and reattempting the fixes above I found a post that mentioned there could be an issue due to hot booting Linux from Windows.

Meaning I restarted Windows and then selected Linux in GRUB. Shutting down my system completely and then starting up and cold booting Linux solved the issue. The audio and microphone are now working again on my internal card.

If non of the steps in the original question work then,

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SOLUTION:

Start Linux from a cold state if dual-booting (shutdown completely, don't restart).

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