No sound for Lenovo C930 with kernels > 5.4

Support Kernel
1

Hi there.

I have a Lenovo C930 and I’m aware of its issues with linux, especially about the microphone (not working at all) and the sound bar, and their partial solutions:


However, since the version 5.4 of linux kernel, there is just no more sound at all (I’ve just tried version 5.9 and same result).
For example in pulseaudio, I get as output: “Dummy output” (while with the previous versions of the kernel I had “built-in speaker” or something like that).
And it is the same for the jack, it doesn’t work, no sound in my headphones (bluetooth speakers work however).

As a temporary solution I’m still using version 4.9 of the kernel (on which both soundbar and audiojack work). But since it seems that the new versions of the kernel don’t fix this issue I fear that this won’t be a long term solution.

Any advice?

I installed sof-firmware (as suggested in Sound not working after updating) with no effect.
When running version 4.9:
part of the output of inxi -Fazy:

System:
  Kernel: 4.19.158-1-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0 
  parameters: BOOT_IMAGE=/boot/vmlinuz-4.19-x86_64 
  root=UUID=*a large number* rw quiet 
  Desktop: i3 4.19 info: polybar dm: GDM 3.38.1 Distro: Manjaro Linux 
Machine:
  Type: Convertible System: LENOVO product: 81C4 v: Lenovo YOGA C930-13IKB 
  serial: <filter> Chassis: type: 31 v: Lenovo YOGA C930-13IKB 
  serial: <filter> 
  Mobo: LENOVO model: LNVNB161216 v: SDK0J40709 WIN serial: <filter> 
  UEFI: LENOVO v: 8GCN32WW date: 10/09/2018 
...
Audio:
  Device-1: Intel Sunrise Point-LP HD Audio vendor: Lenovo 
  driver: snd_hda_intel v: kernel bus ID: 00:1f.3 chip ID: 8086:9d71 
  Sound Server: ALSA v: k4.19.158-1-MANJARO

output for sudo dmesg | grep -E 'snd|sof'

[    0.735462] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[    0.735464] software IO TLB: mapped [mem 0x29c88000-0x2dc88000] (64MB)
[    3.367833] snd_hda_intel 0000:00:1f.3: Applying patch firmware 'hda-jack-retask.fw'
[    3.910643] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[    4.159515] snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC298: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
[    4.159518] snd_hda_codec_realtek hdaudioC0D0:    speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
[    4.159520] snd_hda_codec_realtek hdaudioC0D0:    hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
[    4.159522] snd_hda_codec_realtek hdaudioC0D0:    mono: mono_out=0x0
[    4.159523] snd_hda_codec_realtek hdaudioC0D0:    inputs:
[    4.159525] snd_hda_codec_realtek hdaudioC0D0:      Mic=0x18

When running version 5.9:
inxi -Fazy

System:
  Kernel: 5.9.10-1-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0 
  parameters: BOOT_IMAGE=/boot/vmlinuz-5.9-x86_64 
  root=UUID=*a large number* rw quiet 
  Desktop: i3 4.19 info: polybar dm: GDM 3.38.1 Distro: Manjaro Linux 
Machine:
  Type: Convertible System: LENOVO product: 81C4 v: Lenovo YOGA C930-13IKB 
  serial: <filter> Chassis: type: 31 v: Lenovo YOGA C930-13IKB 
  serial: <filter> 
  Mobo: LENOVO model: LNVNB161216 v: SDK0J40709 WIN serial: <filter> 
  UEFI: LENOVO v: 8GCN32WW date: 10/09/2018 
...
Audio:
  Device-1: Intel Sunrise Point-LP HD Audio vendor: Lenovo driver: snd_soc_skl 
  v: kernel alternate: snd_hda_intel bus ID: 00:1f.3 chip ID: 8086:9d71 
  Sound Server: ALSA v: k5.9.10-1-MANJARO

and sudo dmesg | grep -E 'snd|sof'

[    0.506323] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[    0.506324] software IO TLB: mapped [mem 0x29ca3000-0x2dca3000] (64MB)
[    2.350101] snd_hda_intel 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if info 0x040100
[    2.350105] snd_hda_intel 0000:00:1f.3: Digital mics found on Skylake+ platform, using SST driver
[    2.650843] snd_soc_skl 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if info 0x040100
[    2.650847] snd_soc_skl 0000:00:1f.3: Digital mics found on Skylake+ platform, using SST driver
[    2.655035] snd_soc_skl 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
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