[Pkg-utopia-maintainers] No sound over HDMI with pipewire in Bookworm on Lenovo X1 Carbon 6th gen (i915)

[Konstantin Khomoutov]

Hi!

(I have previously posted this message to debian-multimedia [1] but got no
replies, so sending directly to the maintainers.)

After upgrading my system from Buster to Bookworm, I noticed sound over HDMI
stopped working: when I plug my TV screen into the laptop, it gets detected
properly - I can see it both in the "Sound" page of the GNOME settins app
and in pavucontrol - but no sound can be heard no matter what I do.
I'm positive the TV and the cable are OK as I have another video- and
sound-generating device to check that. The apps which play sound (via
PulseAudio) report no error, pavucontrol shows active volume level bar
suggesting the PulseAudio subsystem at least does handle the sound stream,
but the TV's speakers are silent. The same happens with the sound check
facility of the GNOME settings app: when I click on icons depicting "sound
sources" no error is reported but no sound is produced.
There's also no errors in the system log (`journalctl -b`).

I should admit that this is apparently the only issue compared with Buster on
my system - internal laptop's speakers work the same way (low volume, a known
issue), headphones work OK, Bluetooth works OK.

Since I've noticed GNOME has switched from PulseAudio to PipeWire in Bookworm,
I admit there can be at least two places where the thing could have gotten
screwed: the kernel drivers and PipeWire, and I'm a bit at a loss about how I
should approach to debug it. Namely, is it possible to disable PW and enable
PA with GNOME in Bookworm? The wiki page on PW only explains how to do the
reverse in Buster.

Any help with debugging will be greatly appreciated.
Please CC me as I'me not subscribed.


The relevant output from the kernel's boot log:
--------8<--------
snd_hda_intel 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if info 0x040380
snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC285: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
snd_hda_codec_realtek hdaudioC0D0:    speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
snd_hda_codec_realtek hdaudioC0D0:    hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
snd_hda_codec_realtek hdaudioC0D0:    mono: mono_out=0x0
snd_hda_codec_realtek hdaudioC0D0:    inputs:
snd_hda_codec_realtek hdaudioC0D0:      Mic=0x19
snd_hda_codec_realtek hdaudioC0D0:      Internal Mic=0x12
--------8<--------

~$ lshw -class sound
--------8<--------
  *-multimedia
       description: Audio device
       product: Sunrise Point-LP HD Audio
       vendor: Intel Corporation
       physical id: 1f.3
       bus info: pci at 0000:00:1f.3
       logical name: card0
       logical name: /dev/snd/controlC0
       logical name: /dev/snd/hwC0D0
       logical name: /dev/snd/hwC0D2
       logical name: /dev/snd/pcmC0D0c
       logical name: /dev/snd/pcmC0D0p
       logical name: /dev/snd/pcmC0D3p
       logical name: /dev/snd/pcmC0D7p
       logical name: /dev/snd/pcmC0D8p
       version: 21
       width: 64 bits
       clock: 33MHz
       capabilities: bus_master cap_list
       configuration: driver=snd_hda_intel latency=64
       resources: iomemory:2f0-2ef iomemory:2f0-2ef irq:145 memory:2ffb028000-2ffb02bfff memory:2ffb00000
--------8<--------

 [1] https://lists.debian.org/debian-multimedia/2023/03/msg00075.html