No sound output on Medion Akoya S2218 Z3735F subnotebook

Hello,

the Medion Akoya S2218 is a Z3735F-based subnotebook.

It is possible to install Ubuntu on it, but some devices are not properly supported. I have installed a vanilla 18.04 Ubuntu 64 bit system on it and then updated to the current development version of 18.10. I have also tried the distribution's current 4.17.0-9-generic #10-Ubuntu kernel as well as current 4.19.0-rc kernels.

There is no sound output.

These audio-related modules are being loaded:

snd_soc_sst_cht_bsw_rt5645
snd_intel_sst_acpi
snd_intel_sst_core
snd_soc_sst_atom_hifi2_platform
snd_soc_rt5645
snd_soc_acpi
snd_soc_acpi_intel_match
snd_soc_rl6231
snd_soc_core
snd_compress
ac97_bus
snd_pcm_dmaengine
snd_seq_midi
snd_seq_midi_event
snd_pcm
snd_rawmidi
snd_seq
snd_seq_device
snd_timer
snd
soundcore

These are blacklisted:

blacklist r8723bs
blacklist snd_hdmi_lpe_audio

Pulseaudio still reports a "dummy device".

I have tried finding solutions on the internet. There are various fixes for other Z3735F-based devices, including the tip to blacklist the snd_hdmi_lpe_audio module. None of those fixes helped for mine.

I tried getting help at https://github.com/plbossart/UCM/issues/32 with no response.

/var/log/syslog reports

Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:36 akoya pulseaudio[1075]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:36 akoya pulseaudio[1075]: W: [pulseaudio] module-udev-detect.c: Tried to configure /devices/platform/80860F28:00/cht-bsw-rt5645/sound/card0 (alsa_card.platform-cht-bsw-rt5645) more often than 5 times in 10s
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 6 16:59:55 akoya pulseaudio[1732]: E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-cht-bsw-rt5645" card_name="alsa_card.platform-cht-bsw-rt5645" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 6 16:59:55 akoya pulseaudio[1732]: W: [pulseaudio] module-udev-detect.c: Tried to configure /devices/platform/80860F28:00/cht-bsw-rt5645/sound/card0 (alsa_card.platform-cht-bsw-rt5645) more often than 5 times in 10s

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: libasound2-data 1.1.6-1ubuntu1
ProcVersionSignature: Ubuntu 4.17.0-9.10-generic 4.17.17
Uname: Linux 4.17.0-9-generic x86_64
ApportVersion: 2.20.10-0ubuntu9
Architecture: amd64
Date: Thu Sep 6 17:08:49 2018
Dependencies:

InstallationDate: Installed on 2018-08-28 (9 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-lib
UpgradeStatus: Upgraded to cosmic on 2018-08-28 (9 days ago)