On Ubuntu 20.04 the problem is still happening pretty similar to the one reported by the OP. I've found a new way to fix it though.
Steps to reproduce: 1. turn off machine. 2. leave a headphone plugged in 3. turn on machine (caveat: if your laptop is suspended from here the bug won't be produced) 4. unplug headphone 5. plug headphone -> YOU WON'T HEAR A THING To fix it I do: I open Settings -> Sound and there: 1. Change the Output Device to the normal speakers 2. change the Input Device to internal microphone (not the headphone) 3. Change the Output Device to the headphone 4. Change the Input Device to the headphone (this fix is faster than suspending and bringing it back up). Another fix, is to always unplug the headphones when turning off the laptop. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to alsa-driver in Ubuntu. https://bugs.launchpad.net/bugs/1575078 Title: [XPS 15 9550, Realtek ALC3266] Headphone jack stops working after a while Status in alsa-driver package in Ubuntu: Confirmed Bug description: I'm experiencing a strange behavior with a headphone jack on my laptop. I have an external audio speaker connected to it. When I disconnect the speaker and reconnect it again it stops working. Even more, laptop audio stops working too. And after the reboot, I don't even see any of the audio devices. I've googled a lot and tried different fixes from forums with no luck. After a while, I've accidentally discovered that putting the laptop to the sleep mode and rebooting system after brings audio back to live. Even more, if speakers were attached during this sleep-reboot procedure, they are starting to work as well. However, after the next reboot speakers are not working again. And if I will plug them out and in - problem with completely missing audio returns. P.S. I'm using laptop-mode-tools package on my laptop. Recovery after hibernation made me believe that it's somehow related. But after uninstalling this package nothing really changed. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: alsa-base 1.0.25+dfsg-0ubuntu5 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 Uname: Linux 4.4.0-21-generic x86_64 ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/pcmC0D0p: kop 3224 F...m pulseaudio /dev/snd/controlC0: kop 3224 F.... pulseaudio CurrentDesktop: Unity Date: Tue Apr 26 12:17:03 2016 EcryptfsInUse: Yes InstallationDate: Installed on 2016-04-22 (3 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) PackageArchitecture: all SourcePackage: alsa-driver Symptom: audio Symptom_Card: Встроенное аудио - HDA Intel PCH Symptom_Jack: Black Headphone Out, Left Symptom_Type: Sound works for a while, then breaks Title: [XPS 15 9550, Realtek ALC3266, Black Headphone Out, Left] fails after a while UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 04/07/2016 dmi.bios.vendor: Dell Inc. dmi.bios.version: 01.02.00 dmi.board.name: 0N7TVV dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr01.02.00:bd04/07/2016:svnDellInc.:pnXPS159550:pvr:rvnDellInc.:rn0N7TVV:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: XPS 15 9550 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1575078/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp