Since ~Sep 25 updates HDMI Digital Out disappeared, Headphones stop working

[Example Email]

For last couple of months I've been using 20.04 sound OK on my Dell laptop but since last apt update/upgrade two strange things happened:

1. the HDMI Out sound device completely disappeared and I can't select it in pavucontrol/GNOME/any application

2. when I use Built-In Audio Analog Stereo > Headphones , it works for only few seconds and then stops.

Thus the only sound that remains working is Built-In Audio Analog Stereo > Speakers (cheesy built-in speakers). This is what worked all the time during the ubuntu-bug test.

Please rollback!

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sun Sep 27 10:56:45 2020
InstallationDate: Installed on 2020-08-06 (51 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:PCH successful
Symptom_Card: Built-in Audio - HDA Intel PCH
Symptom_Jack: Digital Out, HDMI
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: None of the above
Title: [G5 5587, Intel Kabylake HDMI, Digital Out, HDMI] Playback problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/29/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.4.1
dmi.board.name: 0M2MWX
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.4.1:bd08/29/2018:svnDellInc.:pnG55587:pvr:rvnDellInc.:rn0M2MWX:rvrA00:cvnDellInc.:ct10:cvr:
dmi.product.family: GSeries
dmi.product.name: G5 5587
dmi.product.sku: 0825
dmi.sys.vendor: Dell Inc.

[Sebastien Bacher (seb128)]

Thank you for your bug report. Did you install any updates on that day? Could you try if booting a previous kernel would resolve the issue?

[Example Email (exampleemailcz)]

Howdy
1. Yes, I am trying to keep my system updated, see apt-history.log.xz2.
Probably for plethora of updates released at about the same time
booting a previous kernel not only didn't help (still no HDMI audio)
but ended up with broken nvidia driver

On Mon, 2020-09-28 at 10:29 +0000, Sebastien Bacher wrote:
> Thank you for your bug report. Did you install any updates on that
> day?Could you try if booting a previous kernel would resolve the
> issue?

[Example Email (exampleemailcz)]

Problem self-healed after upgrading to Ubuntu 20.10 .

[Sebastien Bacher (seb128)]

thanks, closing the report since it's resolved