I am not sure this is an alsa-specific bug. Looks to be more of an issue with the Nvidia card and the way it handles HDMI audio. This also affects a BTO 15CL76 notebook (I7-6700HQ / GTX1060) set in DISCRETE mode. No HDMI audio device shows up at all. The active nvidia driver (as of writing) is nvidia_367. No bbswitch/bumblebee installed as Hybrid mode is disabled.
Suggestions on the nvidia forum are to shutdown your X environment and then run the following commands as root: https://devtalk.nvidia.com/default/topic/609790/linux/no-hdmi-sound-w -optimus-in-linux/ rmmod nvidia echo 1 > /sys/bus/pci/devices/0000\:00\:01.0/remove echo 1 > /sys/bus/pci/rescan This also had no effects - the Nvidia device comes back online but without the audio device showing up. Here's the output of lspci -H 1: fludizz@tongerlo:~$ sudo lspci -H 1 00:00.0 Host bridge: Intel Corporation Sky Lake Host Bridge/DRAM Registers (rev 07) 00:01.0 PCI bridge: Intel Corporation Sky Lake PCIe Controller (x16) (rev 07) 00:14.0 USB controller: Intel Corporation Sunrise Point-H USB 3.0 xHCI Controller (rev 31) 00:16.0 Communication controller: Intel Corporation Sunrise Point-H CSME HECI #1 (rev 31) 00:17.0 SATA controller: Intel Corporation Sunrise Point-H SATA Controller [AHCI mode] (rev 31) 00:1c.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #1 (rev f1) 00:1c.4 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #5 (rev f1) 00:1c.6 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #7 (rev f1) 00:1d.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #9 (rev f1) 00:1f.0 ISA bridge: Intel Corporation Sunrise Point-H LPC Controller (rev 31) 00:1f.2 Memory controller: Intel Corporation Sunrise Point-H PMC (rev 31) 00:1f.3 Audio device: Intel Corporation Sunrise Point-H HD Audio (rev 31) 00:1f.4 SMBus: Intel Corporation Sunrise Point-H SMBus (rev 31) 01:00.0 VGA compatible controller: NVIDIA Corporation Device 1c60 (rev a1) 6d:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device 5287 (rev 01) 6d:00.1 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 12) 6e:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a) 6f:00.0 Non-Volatile memory controller: Intel Corporation Device f1a5 (rev 03) -- 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 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
