audio card is not detected

[Andrew M]

Sound stops working on a laptop running Ubuntu. When the laptop is left alone overnight, the sound works the next day. I'm not quite sure why this would happen. Dummy Ouput is the only device shown once the sound stops working.

"aplay -l" command shows the following:
aplay: device_list:268: no soundcards found...

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.4.0-51.72-generic 4.4.30
Uname: Linux 4.4.0-51-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CurrentDesktop: Unity
Date: Sat Dec 3 22:37:12 2016
EcryptfsInUse: Yes
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Title: PCI/internal sound card not detected
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/11/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 5.12
dmi.board.asset.tag: Tag 12345
dmi.board.name: N24_25BU
dmi.board.vendor: Notebook
dmi.board.version: lemu7
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Notebook
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr5.12:bd10/11/2016:svnNotebook:pnN24_25BU:pvrlemu7:rvnNotebook:rnN24_25BU:rvrlemu7:cvnNotebook:ct10:cvrN/A:
dmi.product.name: N24_25BU
dmi.product.version: lemu7
dmi.sys.vendor: Notebook

[Jason Hines (jasonehines)]

I had this issue too. It was fixed by linux-firmware 1.161.1 in the system76 ppa