[MTL][ALC298][Samsung Galaxy Book2 Pro 950XGK] Internal speakers are silent (SOF IPC4, HDMI/HP OK)

[antpln]

Hi,

On a Samsung Galaxy Book2 Pro Special Edition (950XGK) the built-in speakers are completely silent with the SOF driver.
Headphones, HDMI audio and Bluetooth all work fine.

Hardware

• Laptop: Samsung Galaxy Book2 Pro Special Edition 950XGK
  DMI: SAMSUNG ELECTRONICS CO., LTD. / 950XGK
• Audio controller: Intel Meteor Lake-P HD Audio Controller
  8086:7e28, subsystem 144d:c896, driver sof-audio-pci-intel-mtl
• Codec: Realtek ALC298 (10ec:0298), same subsystem 144d:c896

Software

• Distro: EndeavourOS (Arch based)
• Kernel: 6.17.8-arch1-1
• Audio stack: PipeWire + WirePlumber
• SOF bits from dmesg:
  • Firmware: intel/sof-ipc4/mtl/sof-mtl.ri
  • Topology: intel/sof-ace-tplg/sof-hda-generic-2ch.tplg
  • Machine driver: skl_hda_dsp_generic

Symptoms

• ALSA sees the HDA card and devices:

  • card 0: sof-hda-dsp - sof-hda-dsp
  • Playback devices: HDA Analog (0), HDMI1 (3), HDMI2 (4), HDMI3 (5), Deepbuffer HDA Analog (31)
  • Capture devices: HDA Analog (0), DMIC Raw (6)

• PipeWire exposes a ...HiFi__Speaker__sink that can be selected as default output.

• Running a direct ALSA test on the analog device succeeds but produces no sound on the built-in speakers.
  Headphone jack, HDMI audio and Bluetooth all work correctly with the same kernel and stack.

Mixer state

-Master, Speaker, Pre Mixer Analog and Post Mixer Analog are at 100% and unmuted.

-Auto-Mute Mode is set to Disabled.

-Headphone volume is also unmuted when testing, but only the headphones produce sound.

Things I tried

- Verified volume and mute state with amixer for:

    Master, Speaker, Headphone, Pre Mixer Analog, Post Mixer Analog, Loopback Mixing.

- Tested both through PipeWire and directly with ALSA (speaker-test on hw:0,0).

- Tried the necessary-verbs.sh workaround from issue #4055, including setting:

options snd-sof-intel-hda-common hda_model=alc298-samsung-amp-v2-2-amps

in /etc/modprobe.d/. This did not restore internal speaker output.

Logs and dumps

I am attaching these as files:

codec0-alc298.txt
dmi-product_name.txt
dmi-sys_vendor.txt

amixer-scontents.txt
amixer-scontrols.txt
arecord-l.txt
aplay-l.txt
asound-cards.txt

codec0-alc298.txt - /proc/asound/card0/codec#0

amixer-scontrols.txt and amixer-scontents.txt

aplay-l.txt, arecord-l.txt, asound-cards.txt

lspci-audio.txt

dmi-sys_vendor.txt, dmi-product_name.txt

If you need an extra trace (alsa-info, SOF logs, different topology or module options) I am happy to rerun tests.