Have a similar issue with my HP Pavilion DV6 Laptop under both Ubuntu 16.04 and Ubuntu Mate 16.04 using pulse audio.
Video still displays out of HDMI port to TV but Audio hardware device disappears from sound applet (in my case "mate-volume-control-applet"). Curiously the HDMI device is visible at some level to aplay $ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: 92HD81B1X5 Analog [92HD81B1X5 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 Work-Around (temporarily SOLVES issue ... until the next time) ----------- I have developed the following work-around (for Mate ... but you can adapt it to standard Ubuntu) that recovers the HDMI sound (perhaps it may help users get by and/or some smart developer to track down the root cause):- Step 0: Open your terminal ... Step 1: Kill the (non-detecting) volume control process $ kill -9 $(ps aux |grep -v 'sudo\|grep' |grep -e "mate-volume-control-applet"| awk {'print $2'}) Step 2: Relaunch the volume-control process $ sudo mate-volume-control-applet Step 3: Then at the blinking terminal type ^Z Step 4: Now complete the manual terminal tty disassociation by typing $ bg Step 5: Now when you right click on your "mate-volume-control-applet" go to > Sound Preferences > Hardware Tab > Profile Drop Down ... should now show all the available sound devices including the HDMI output to the TV. ----------- The volume control applet just seems to forget about the sound hardware, never refreshes nor updates even with the HDMI lead being disconnected and reconnected. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to alsa-driver in Ubuntu. https://bugs.launchpad.net/bugs/1377653 Title: HDMI sound output not detected / NVIDIA optimus laptop Status in alsa-driver package in Ubuntu: Confirmed Status in pulseaudio package in Ubuntu: Confirmed Bug description: Hi, not sure if this is an alsa or nvidia/nouveau bug. HDMI audio output doesn't appear in sound settings output panel. Audio works well on internal speakers, but it seems there is no way to make it output to hdmi... The laptop has optimus NVIDIA+Intel. The behaviour is the same with nouveau or nvidia proprietary driver. Please let me know if further testing is required ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: alsa-base 1.0.25+dfsg-0ubuntu4 ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6 Uname: Linux 3.13.0-36-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.14.1-0ubuntu3.5 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: sam 2295 F.... pulseaudio CurrentDesktop: Unity CurrentDmesg: Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied Date: Sun Oct 5 17:05:35 2014 InstallationDate: Installed on 2014-04-21 (166 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417) 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: 11/02/2012 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: N56VZ.215 dmi.board.asset.tag: ATN12345678901234567 dmi.board.name: N56VZ dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: 1.0 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: ASUSTeK COMPUTER INC. dmi.chassis.version: 1.0 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrN56VZ.215:bd11/02/2012:svnASUSTeKCOMPUTERINC.:pnN56VZ:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnN56VZ:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0: dmi.product.name: N56VZ dmi.product.version: 1.0 dmi.sys.vendor: ASUSTeK COMPUTER INC. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1377653/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp