[BUG] No sound from internal speakers on ASUS Vivobook 14 Flip (Intel Lunar Lake / TAS2781 / ALC294)

[CH0gun69]

Hello, I would like to report a possible audio support issue on my ASUS Vivobook 14 Flip with Intel Lunar Lake.

System information:

• Laptop: ASUS Vivobook 14 Flip (TP3407SA_QL528WA)
• CPU: Intel Core Ultra 5 226V (Lunar Lake)
• Distro: Linux Mint
• Kernel: 6.17.0-23-generic

Audio information:

• Driver: sof-audio-pci-intel-lnl
• Codec: Realtek ALC294
• Smart amp: TAS2781

Problem:
The system detects the audio devices correctly, and audio playback appears to work normally in software, but the internal speakers produce no sound.

speaker-test -c 2 runs successfully without any errors, but there is still no audible output from the built-in speakers.

Relevant logs:

aplay -l

card 0: sofhdadsp [sof-hda-dsp], device 0: HDA Analog
card 0: sofhdadsp [sof-hda-dsp], device 3: HDMI1
card 0: sofhdadsp [sof-hda-dsp], device 4: HDMI2
card 0: sofhdadsp [sof-hda-dsp], device 5: HDMI3

inxi -A

Audio:
  Device-1: Intel Lunar Lake-M HD Audio
  driver: sof-audio-pci-intel-lnl
  API: ALSA
  Server-1: PipeWire

Important dmesg output:

snd_hda_codec_alc269 ehdaudio0D0: ALC294: picked fixup for PCI SSID 1043:10a4
snd_hda_codec_alc269 ehdaudio0D0: autoconfig for ALC294:
speaker_outs=0
hp_outs=1

It seems the headphones are detected, but the speaker path may not be configured correctly.

I also noticed:

snd_sof_intel_hda_common: unknown parameter 'hda_model' ignored

SOF firmware loads successfully:

Firmware file: intel/sof-ipc4/lnl/sof-lnl.ri
Topology file: intel/sof-ipc4-tplg/sof-hda-generic-2ch.tplg
Booted firmware version: 2.13.0.1

This may be a missing quirk/fixup for this ASUS model or a TAS2781 speaker amplifier routing issue.

Thank you.

[CH0gun69]

Update: I noticed that only USB audio devices work correctly. When I connect headphones via a USB-to-3.5mm adapter (or use a USB DAC), the sound works fine. However, the internal speakers and the built-in 3.5mm jack remain silent.

This further suggests that the issue is specifically related to the internal routing or the TAS2781 amplifier initialization for this model.