[K501UX, Conexant CX20751/2, Black Headphone Out, Right] Not able to get sound out of my headphones

[Daniel Mouris]

Not Able to get sound out of my headphones from ubuntu 16.04

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13
Uname: Linux 4.4.0-28-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: daniel 1580 F.... pulseaudio
CurrentDesktop: Unity
Date: Sat Jul 16 15:22:01 2016
InstallationDate: Installed on 2016-05-28 (49 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
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_DevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: daniel 1580 F.... pulseaudio
                      daniel 30828 F.... alsamixer
Symptom_Jack: Black Headphone Out, Right
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: No sound at all
Title: [K501UX, Conexant CX20751/2, Black Headphone Out, Right] No sound at all
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/20/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: K501UX.209
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: K501UX
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: ATN12345678901234567
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrK501UX.209:bd01/20/2016:svnASUSTeKCOMPUTERINC.:pnK501UX:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnK501UX:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.name: K501UX
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
mtime.conffile..etc.modprobe.d.alsa-base.conf: 2016-07-16T14:24:41.418524

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Raphaël Droz (raphael-droz)]

E555, same chip, same problem.
This guy too:
https://askubuntu.com/questions/585709/headphones-not-recognized/674501
This one too, but got it fixed using the right "model":
http://www.linuxquestions.org/questions/slackware-14/slackware64-on-lenovo-g50-70-no-sound-4175514003/
and here too (but managed to solve it):
https://bbs.archlinux.org/viewtopic.php?id=224771
Same chip, but opposite issue (sound in the headphone only);
https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1654857