ALC1220: inserting headphone to front panel triggers auto-mute on both speaker and headphone

[GLenn]

Jack is confirmed to be working:
Using alsamixer and disabling auto-mute enables audio output on both speaker and front headphone jack
Same problem with Asus Prime Z370-A (also ALC1220) when using same Ubuntu installation.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-112.135-generic 4.4.98
Uname: Linux 4.4.0-112-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: wenzler 6045 F.... pulseaudio
 /dev/snd/pcmC1D0c: wenzler 6045 F...m pulseaudio
 /dev/snd/pcmC1D0p: wenzler 6045 F...m pulseaudio
 /dev/snd/controlC1: wenzler 6045 F.... pulseaudio
CurrentDesktop: LXQt
Date: Sat Feb 17 15:05:41 2018
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_Card: HD-Audio Generic - HD-Audio Generic
Symptom_Jack: Green Headphone Out, Front
Symptom_Type: No auto-mute between outputs
Title: [System Product Name, Realtek Generic, Green Headphone Out, Front] No automute
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/22/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3803
dmi.board.asset.tag: Default string
dmi.board.name: ROG STRIX X370-F GAMING
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr3803:bd01/22/2018:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnROGSTRIXX370-FGAMING:rvrRevX.0x:cvnDefaultstring:ct3:cvrDefaultstring:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer