EAC3 passthrough doesn't work after suspend

[Sven N.]

I set up everything for passthrough to hdmi. I enabled all the options in pulseaudio config and it works after a reboot. Once I put my notebook to sleep and wake it up again, EAC3 passthrough is gone even though the options are still checked. DTS and regular AC3 passthrough still works, just EAC3 is gone.

I also tried
$ systemctl --user stop pulseaudio.socket
$ systemctl --user stop pulseaudio.service
$ pulseaudio -k
# alsa force-reload
$ pulseaudio --start

The only thing that helps is a reboot which is kinda not Linux-like...

pactl list sinks
Sink #0
State: SUSPENDED
Name: alsa_output.pci-0000_00_1f.3.hdmi-stereo
Description: Built-in Audio Digital Stereo (HDMI)
Driver: module-alsa-card.c
Sample Specification: s16le 2ch 48000Hz
Channel Map: front-left,front-right
Owner Module: 7
Mute: no
Volume: front-left: 65536 / 100% / 0,00 dB, front-right: 65536 / 100% / 0,00 dB
balance 0,00
Base Volume: 65536 / 100% / 0,00 dB
Monitor Source: alsa_output.pci-0000_00_1f.3.hdmi-stereo.monitor
Latency: 0 usec, configured 0 usec
Flags: HARDWARE DECIBEL_VOLUME LATENCY SET_FORMATS
Properties:
alsa.resolution_bits = "16"
device.api = "alsa"
device.class = "sound"
alsa.class = "generic"
alsa.subclass = "generic-mix"
alsa.name = "HDMI 0"
alsa.id = "HDMI 0"
alsa.subdevice = "0"
alsa.subdevice_name = "subdevice #0"
alsa.device = "3"
alsa.card = "0"
alsa.card_name = "HDA Intel PCH"
alsa.long_card_name = "HDA Intel PCH at 0x91338000 irq 157"
alsa.driver_name = "snd_hda_intel"
device.bus_path = "pci-0000:00:1f.3"
sysfs.path = "/devices/pci0000:00/0000:00:1f.3/sound/card0"
device.bus = "pci"
device.vendor.id = "8086"
device.vendor.name = "Intel Corporation"
device.product.id = "a348"
device.product.name = "Cannon Lake PCH cAVS"
device.form_factor = "internal"
device.string = "hdmi:0"
device.buffering.buffer_size = "65536"
device.buffering.fragment_size = "32768"
device.access_mode = "mmap+timer"
device.profile.name = "hdmi-stereo"
device.profile.description = "Digital Stereo (HDMI)"
device.description = "Built-in Audio Digital Stereo (HDMI)"
module-udev-detect.discovered = "1"
device.icon_name = "audio-card-pci"
Ports:
hdmi-output-0: HDMI / DisplayPort (priority: 5900, available)
Active Port: hdmi-output-0
Formats:
ac3-iec61937, format.rate = "[ 32000, 44100, 48000 ]"
eac3-iec61937, format.rate = "[ 32000, 44100, 48000 ]"
mpeg-iec61937, format.rate = "[ 32000, 44100, 48000 ]"
dts-iec61937, format.rate = "[ 32000, 44100, 48000 ]"
mpeg2-aac-iec61937, format.rate = "[ 32000, 44100, 48000 ]"
pcm

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: vlc 3.0.9.2-1
ProcVersionSignature: Ubuntu 5.4.0-45.49-generic 5.4.55
Uname: Linux 5.4.0-45-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.8
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Sun Sep 6 09:26:26 2020
InstallationDate: Installed on 2019-09-20 (351 days ago)
InstallationMedia: Kubuntu 19.10 "Eoan Ermine" - Alpha amd64 (20190919)
SourcePackage: vlc
UpgradeStatus: No upgrade log present (probably fresh install)

[Sven N. (drecksoft)]

I just rechecked the output of alsa reload

(failed: modules still loaded: snd-hda-intel snd-intel-dspcfg snd-hda-codec-hdmi snd-hda-codec-realtek snd-hda-codec-generic snd-hda-codec snd-hda-core snd-hwdep snd-pcm snd-timer)

It seems there was still a pulseaudio running. I now managed to unload all modules but after reloading them there is no sound at all. So reboot it is...

[Sven N. (drecksoft)]

I now managed to unload / load all alsa modules properly and sound is working afterwards but sill no change to EAC3 passthrough (AC3/DTS still working). I used:

pulseaudio -k
sudo alsa force-reload
pulseaudio --start

There is a workaround: Unplug the HDMI cable, plug it in again and and switch the output to HDMI again.

I think this is an ALSA, Pulseaudio or driver bug, not VLC.

Also if I unplug the HDMI cable while audio output is set to HDMI and plug it back in, I'd expect the audio output to be automatically switched back to HDMI instead of being left on internal speakers.