output volume is randomly changing level

[Jamie Ryan Mascola]

I've confirmed that the volume control for the PC is changing of it's own volition. The volume applet in the top pane (using Ubuntu Gnome 15.10) and the volume sliders in alsamixer are changing every 10 seconds to a random level. The interval of the changes is not periodic (random time interval and output volume). It does look like the fader goes to zero before choosing a new random volume level.

I am running 5.1 surround, and the motherboard supports the feature. I had this problem while running while 15.04 with a single stereo (green jack, rear) output speaker system. It seemed to be repaired in an update, because the issue disappeared after a while. I removed the USB peripherals that I usually have attached which control volume (eg keyboard) I even went as far as to disable bluetooth in case that was causing issues.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.2.0-22.27-generic 4.2.6
Uname: Linux 4.2.0-22-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: jamie 1543 F.... pulseaudio
 /dev/snd/controlC2: jamie 1543 F.... pulseaudio
 /dev/snd/controlC0: jamie 1543 F.... pulseaudio
CurrentDesktop: GNOME
Date: Tue Dec 29 21:00:05 2015
InstallationDate: Installed on 2015-12-29 (0 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_Card: Built-in Audio - HDA Intel PCH
Symptom_Jack: Green Line Out, Rear
Symptom_Type: Volume slider, or mixer problems
Title: [All Series, Realtek ALC887-VD, Green Line Out, Rear] volume slider problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/16/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2103
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: B85M-G R2.0
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2103:bd04/16/2015:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnB85M-GR2.0:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: All Series
dmi.product.version: System Version
dmi.sys.vendor: ASUS

[Raymond (superquad-vortex2)]

If channel mode is 6ch, rear mic and line in were retasked, volume is controlled by bass, balance and fade controls

Simple mixer control 'Channel Mode',0 Capabilities: enum Items: '2ch' '4ch' '6ch' Item0: '6ch'

[Raymond (superquad-vortex2)]

Default sample spec: s16le 2ch 44100Hz
Default channel map: front-left,front-right
Default sink name: alsa_output.pci-0000_00_1b.0.analog-surround-51

[Raymond (superquad-vortex2)]

 ports:
  analog-input-front-mic: Front Microphone (priority 8500, latency offset 0 usec, available: no)
   properties:
    device.icon_name = "audio-input-microphone"
  analog-input-rear-mic: Rear Microphone (priority 8200, latency offset 0 usec, available: yes)
   properties:
    device.icon_name = "audio-input-microphone"
  analog-input-linein: Line In (priority 8100, latency offset 0 usec, available: yes)
   properties:

 active port: <analog-input-rear-mic>

if rear mic and line in were retasked , why rear mic still active port

[Launchpad Janitor (janitor)]

[Expired for alsa-driver (Ubuntu) because there has been no activity for 60 days.]