Comment 0 for bug 1845810

Since linux-image-4.15.0-60-generic 4.15.0-60.67, the background noise in my headphones has increased to unreasonable levels. In linux-image-4.15.0-58-generic 4.15.0-58.64 and previous kernels the noise was present but at a bearable level, which I had always assumed was a hardware design issue. Now, with the increased noise floor, the headphone socket is essentially unusable.

This is a regression in a stable release (Bionic). The problem consistently reproduces as follows:

OK: linux-image-4.15.0-58-generic 4.15.0-58.64
BAD: linux-image-4.15.0-60-generic 4.15.0-60.67
BAD: linux-image-4.15.0-62-generic 4.15.0-62.69
BAD: linux-image-4.15.0-64-generic 4.15.0-64.73

Steps to reproduce:

Hardware: Dell XPS 9360 (shipped with Ubuntu). I'm using a manually reinstalled Ubuntu Bionic, not the OEM installation. Mostly everything is on defaults.

1. Boot with no headphones connected
2. Log in
3. Plug the headphones in

Expected: normal noise level
Actual: very high noise level. Playback does work correctly but the SnR is terrible.

The "Select Audio Device" prompt appears, but the noise problem is present before I make a selection. If I select Headphones or Headset (I'm using a headset) then the noise remains after a brief (~0.5s) interruption. If I select Microphone then the noise goes, but then the audio comes through the speakers and not the headset as required.

I have tried messing with alsamixer but haven't found anything to explain or reduce the noise. Switching to a previous kernel fixes the problem immediately with no settings change required.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.15.0-64.73-generic 4.15.18
Uname: Linux 4.15.0-64-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: robie 2126 F.... pulseaudio
                      robie 3648 F.... alsamixer
CurrentDesktop: ubuntu:GNOME
Date: Sat Sep 28 23:51:05 2019
InstallationDate: Installed on 2017-05-11 (870 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170507)
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: Black Headphone Out, Front
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: High background noise, or volume is too low
Title: [XPS 13 9360, Realtek ALC3246, Black Headphone Out, Front] Background noise or low volume
UpgradeStatus: Upgraded to bionic on 2018-07-28 (427 days ago)
dmi.bios.date: 03/14/2019
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 2.11.0
dmi.board.name: 00GCYR
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr2.11.0:bd03/14/2019:svnDellInc.:pnXPS139360:pvr:rvnDellInc.:rn00GCYR:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.family: XPS
dmi.product.name: XPS 13 9360
dmi.sys.vendor: Dell Inc.