built-in audio became inactive after nvidia gfx card installation

[Duce Mollari]

No sound, built-in audio is grayed, HDMI is the only option.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ducemollari 3730 F.... pulseaudio
CurrentDesktop: KDE
Date: Mon Jul 25 15:15:41 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-05-06 (80 days ago)
InstallationMedia: Kubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:NVidia failed
Symptom_Card: High Definition Audio Controller - HDA NVidia
Symptom_Jack: Digital Out, HDMI
Symptom_Type: None of the above
Title: [HP Compaq dc5800 Small Form Factor, Nvidia GPU 0b HDMI/DP, Digital Out, HDMI] Playback problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/26/2015
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 786F2 v01.60
dmi.board.asset.tag: CZC8304M4Z
dmi.board.name: 2820h
dmi.board.vendor: Hewlett-Packard
dmi.chassis.asset.tag: CZC8304M4Z
dmi.chassis.type: 4
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr786F2v01.60:bd10/26/2015:svnHewlett-Packard:pnHPCompaqdc5800SmallFormFactor:pvr:rvnHewlett-Packard:rn2820h:rvr:cvnHewlett-Packard:ct4:cvr:
dmi.product.name: HP Compaq dc5800 Small Form Factor
dmi.sys.vendor: Hewlett-Packard