Audio channels over HDMI not detected at E-OS install

General system Gaming, sound and video
1

I have a HTPC which I used to run with a Kubuntu system for more than 8 years.

After a broken upgrade (ran out of space), I decided to set the system up from scratch with E-OS and get rid of all the accumulated cruft. So far, so good.

The PC is connected to a Denon AV Receiver which passes on the video from a Nvidia RTX 3060 to a 4k monitor and the audio to the speakers in a 5.1 setup.

All the years with Kubuntu, I could just push whatever audio my videos had to the receiver to deal with it, never a problem. The sound setup gave me all the options for this HDMI audio, stereo, 5.1, 7.1. The hardware is not the issue.

After the E-OS install though, I only get 2 channels for the HDMI audio. In the KDE sound setup, I can switch to ‘Pro Audio’ and get more choices – besides the ‘HDMI audio’ one I get HDMI audio 7, 8 and 9 – but the only which with audible sound still has only the two channels (it’s the HDMI audio one without a trailing number).

Any ideas how to debug and fix this? I would very much like to get the 5.1 setup back.

2

Did you run your setup using nvidia or default ? The nvidia drivers might not be installed and you might be running on Nouveau.

Try running :

sudo nvidia-inst -t

What does it say ? I personally run on a 4090 and I’m using a similar setup with a Denon AVR-S970H in 4K and with the 5.1 profile working.

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3

I ran sudo nvidia-inst -t:

[emk2203@NanoxiaDS3 ~]$ sudo nvidia-inst -t
[sudo] Passwort für emk2203: 
2026-09-22 08:20:27: Info: 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA106 [GeForce RTX 3060 Lite Hash Rate] [10de:2504] (rev a1) (prog-if 00 [VGA controller])
2026-09-22 08:20:27: Info: Currently installed packages related to Nvidia:
2026-09-22 08:20:27:       egl-gbm 1.1.4-1
2026-09-22 08:20:27:       egl-wayland 4:1.1.22-1
2026-09-22 08:20:27:       egl-wayland2 1.0.2-1
2026-09-22 08:20:27:       egl-x11 1.0.6-1
2026-09-22 08:20:27:       libva-nvidia-driver 0.0.18-1
2026-09-22 08:20:27:       libvdpau 1.5-4
2026-09-22 08:20:27:       libxnvctrl 615.71.09-1
2026-09-22 08:20:27:       linux-firmware-nvidia 20260916-1
2026-09-22 08:20:27:       nvidia-inst 26.1.1-1
2026-09-22 08:20:27:       nvidia-open 615.71.09-3
2026-09-22 08:20:27:       nvidia-settings 615.71.09-1
2026-09-22 08:20:27:       nvidia-utils 615.71.09-1
2026-09-22 08:20:27:       opencl-nvidia 615.71.09-1
2026-09-22 08:20:27: Info: inxi -Gza
Graphics:
  Device-1: NVIDIA GA106 [GeForce RTX 3060 Lite Hash Rate] vendor: ASUSTeK driver: nvidia
    v: 615.71.09 alternate: nouveau,nvidia_drm non-free: 550-6xx.xx+ status: current (as of 2026-07)
    arch: Ampere code: GAxxx process: TSMC n7 (7nm) built: 2020-2023 pcie: gen: 1 speed: 2.5 GT/s
    lanes: 16 link-max: gen: 4 speed: 16 GT/s ports: active: HDMI-A-2 empty: DP-1, DP-2, DP-3,
    HDMI-A-1 bus-ID: 01:00.0 chip-ID: 10de:2504 class-ID: 0300
  Display: unspecified server: X.org v: 1.21.1.24 with: Xwayland v: 24.1.13
    compositor: kwin_wayland driver: gpu: nv_platform,nvidia,nvidia-nvswitch tty: 197x56
  Monitor-1: HDMI-A-2 model: Denon DENON-AVRHD serial: <filter> built: 2015 res: 3840x2160
    dpi: 61 gamma: 1.2 size: 597x336mm (23.5x13.23") diag: 1836mm (72.3") ratio: 16:9 modes:
    max: 3840x2160 min: 1024x768
  API: EGL v: 1.5 hw: drv: nvidia platforms: device: 0 drv: nvidia device: 2 drv: swrast gbm:
    drv: nvidia surfaceless: drv: nvidia inactive: wayland,x11,device-1
  API: OpenGL v: 4.6.0 compat-v: 4.6 vendor: mesa v: 26.2.3-arch1.1 note: console (EGL sourced)
    renderer: NVIDIA GeForce RTX 3060/PCIe/SSE2, llvmpipe (LLVM 22.1.8 256 bits)
  API: Vulkan v: 1.4.357 layers: 2 device: 0 type: discrete-gpu name: NVIDIA GeForce RTX 3060
    driver: nvidia v: 615.71.09 device-ID: 10de:2504 surfaces: N/A
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo de: kscreen-console,kscreen-doctor
    gpu: nvidia-settings,nvidia-smi wl: wayland-info x11: xdpyinfo, xprop, xrandr
2026-09-22 08:20:29: Info: nvidia-inst version 26.1.1-1
2026-09-22 08:20:29: Info: Command line: nvidia-inst -t
2026-09-22 08:20:29: Info: Selected mode: nvidia (Nvidia's open source)
2026-09-22 08:20:29: Info: Installing packages: dkms nvidia-open-dkms nvidia-hook
2026-09-22 08:20:29: Info: Removing packages: nvidia-open nvidia-utils
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
COMMANDS TO RUN:
    pacman -Rs --noconfirm --noprogressbar --nodeps nvidia-open nvidia-utils
    pacman -Syuq --noconfirm --noprogressbar --needed dkms nvidia-open-dkms nvidia-hook
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

but can’t make head or tail from the output. It looks like the nvidia-open driver is installed, which was also the same on the old, working installation. I think I had dkms on the old system for the driver, so the suggestions seem sensible. But why isn’t it working ‘as is’?

I can see what commands to run, but why the change?

Anyway, I did the suggested changes manually (didn’t work directly with nvidia-inst) and removed nvidia-settings as well to make it work, and after the restart, no change. I still have only HDMI stereo, and when I switch to Pro Audio, the audio test gives me only static noise instead of front left/right.

Kind of frustrated now. I can’t find any way to approach this, maybe pipewire? But how? The infuriating fact is that this worked under Kubuntu since 2018 until the last update a few days ago ran out of space.

When I run wpctl status, I get

PipeWire 'pipewire-0' [1.6.8, emk2203@NanoxiaDS3, cookie:3166352577]
 └─ Clients:
        32. kwin_wayland                        [1.6.8, emk2203@NanoxiaDS3, pid:720]
        33. WirePlumber                         [1.6.8, emk2203@NanoxiaDS3, pid:782]
        42. WirePlumber [client]                [1.6.8, emk2203@NanoxiaDS3, pid:782]
        53. wpctl                               [1.6.8, emk2203@NanoxiaDS3, pid:1409]
        64. pipewire                            [1.6.8, emk2203@NanoxiaDS3, pid:875]
        65. libcanberra                         [1.6.8, emk2203@NanoxiaDS3, pid:851]
        66.                                     [1.6.8, emk2203@NanoxiaDS3, pid:851]
        67. xdg-desktop-portal                  [1.6.8, emk2203@NanoxiaDS3, pid:1040]
        68. plasmashell                         [1.6.8, emk2203@NanoxiaDS3, pid:859]
        69. libcanberra                         [1.6.8, emk2203@NanoxiaDS3, pid:859]
        70.                                     [1.6.8, emk2203@NanoxiaDS3, pid:859]

Audio
 ├─ Devices:
 │      43. GA106 High Definition Audio Controller [alsa]
 │      44. Internes Audio                      [alsa]
 │  
 ├─ Sinks:
 │  *   51. GA106 High Definition Audio Controller Digitales Stereo (HDMI) [DENON-AVRHD] [vol: 1.00]
 │  
 ├─ Sources:
 │  
 ├─ Filters:
 │  
 └─ Streams:

Video
 ├─ Devices:
 │  
 ├─ Sinks:
 │  
 ├─ Sources:
 │  
 ├─ Filters:
 │  
 └─ Streams:

Settings
 └─ Default Configured Devices:
         0. Audio/Sink    alsa_output.pci-0000_01_00.1.hdmi-stereo

which doesn’t help me. Any ideas?

4

Answering my own post so I can flag this as a quick solution without wall of text:

The attached TV (the monitor) is stereo and this is what gets detected. The capabilities of the receiver don’t play a role here, even though it is set to 5.1. This is an EDID handshake issue (AI was really helpful for a change to find this out)

To overcome this, the module option options snd_hda_codec_hdmi static_hdmi_pcm=1 needs to be set.

Make a file with sudo vim /etc/modprobe.d/nvidia_hdmi.conf and put the above line in.

Reboot and change audio settings. That’s all that’s needed.