[BUG] ASUS ROG Flow Z13 GZ302EA: ALC294 internal mic routing broken; ACP/PDM forced path unusable

[dionisboss]

Pre-flight checklist

• I have searched existing issues and this is not a duplicate.
• I have read the Contributing Guidelines.
• I have verified the issue is reproducible with the latest available CachyOS kernel.
• I have tried to reproduce the issue on Arch Linux's linux kernel.

Upstream / vanilla kernel check

I have not tested with a vanilla/upstream kernel

Kernel variant

linux-cachyos (EEVDF, Clang)

System information (cachyos-bugreport.sh)

cachyos-bugreport.sh hangs on my system. Manual information below.

Linux ai 7.0.11-1-cachyos #1 SMP PREEMPT_DYNAMIC Fri, 05 Jun 2026 09:37:35 +0000 x86_64 GNU/Linux

ROG Flow Z13 GZ302EA_GZ302EA
GZ302EA
ASUSTeK COMPUTER INC.
1.0

Manual system information (if cachyos-bugreport.sh is unavailable)

ACP device:

c4:00.5 Multimedia controller [0480]: Advanced Micro Devices, Inc. [AMD] Audio Coprocessor [1022:15e2] (rev 70)
        Subsystem: ASUSTeK Computer Inc. Device [1043:1fb3]
        Kernel driver in use: snd_acp_pci
        Kernel modules: snd_pci_acp3x, snd_rn_pci_acp3x, snd_pci_acp5x, snd_pci_acp6x, snd_acp_pci, snd_rpl_pci_acp6x, snd_pci_ps, snd_sof_amd_renoir, snd_sof_amd_rembrandt, snd_sof_amd_vangogh, snd_sof_amd_acp63, snd_sof_amd_acp70

ALSA cards:

0 [Generic        ]: HDA-Intel - HD-Audio Generic
                     HD-Audio Generic at 0xa0448000 irq 156
1 [Generic_1      ]: HDA-Intel - HD-Audio Generic
                     HD-Audio Generic at 0xa0440000 irq 158

Capture devices:

**** List of CAPTURE Hardware Devices ****
card 1: Generic_1 [HD-Audio Generic], device 0: ALC294 Analog [ALC294 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Relevant loaded modules:

snd_acp70
snd_acp_pdm
snd_acp_i2s
snd_acp_pcm
snd_sof_amd_acp70
snd_pci_ps
snd_acp_pci
snd_amd_acpi_mach
snd_acp_legacy_common
snd_soc_acpi_amd_match
snd_hda_intel
snd_hda_codec_alc269
snd_hda_codec_realtek_lib

Bug description

The internal microphone array on ASUS ROG Flow Z13 2025 GZ302EA does not appear as an ACP70/DMIC/PDM capture device.

The laptop has a built-in 3-microphone array according to ASUS specifications, but Linux only exposes the HDA/Realtek fallback path: ALC294 Analog.

The AMD ACP70 device is detected:

• PCI ID: 1022:15e2 rev 70
• Subsystem: 1043:1fb3
• Kernel driver in use: snd_acp_pci

ACP/PDM-related modules are loaded, including snd_acp70 and snd_acp_pdm, but no ACP/DMIC/PDM ALSA capture card is created.

Only this capture device is available:

card 1: Generic_1 [HD-Audio Generic], device 0: ALC294 Analog [ALC294 Analog]

This looks like missing ACP70/DMIC machine driver support or a missing quirk/match for ASUS GZ302EA / 1043:1fb3.

Steps to reproduce

1. Boot ASUS ROG Flow Z13 2025 GZ302EA on linux-cachyos 7.0.11.
2. Run: lspci -nnk -s c4:00.5
3. Run: cat /proc/asound/cards
4. Run: arecord -l
5. Observe that ACP70 is detected, but only the HDA/Realtek ALC294 Analog capture device is exposed.

Expected behavior

The internal 3-microphone array should be exposed as an ACP70/DMIC/PDM ALSA capture device, so PipeWire can use the real digital microphone array.

Actual behavior

No ACP70/DMIC/PDM capture card is created.

Only the HDA/Realtek fallback capture device is available:

card 1: Generic_1 [HD-Audio Generic], device 0: ALC294 Analog [ALC294 Analog]

Logs / stack traces

Additional system information

No response

[dionisboss]

Realtek ALC294 1043:1fb3: combo jack headphone works, headset/aux mic does not.
Standard model presets headset-mode/headset-mic/asus-zenbook did not expose working mic.
Manual pin overrides 0x18/0x19/0x1a/0x1b tested; 0x19 creates analog-input-mic but captures only noise.

[dionisboss]

Update 2026-06-19: narrowed scope

Initial suspicion was missing ACP70/PDM machine-driver support. That path was tested.

Forcing ACP/PDM via ACPI _WOV -> 1 creates acp-pdm-mach and dmic-codec, but capture is unusable: samples rail at -32768. So a simple ACP/PDM enable quirk is not sufficient.

Current actionable problem for CachyOS/community:

• Machine: ASUS ROG Flow Z13 GZ302EA, SSID 1043:1fb3, Realtek ALC294.
• Upstream maps 1043:1fb3 to ALC287_FIXUP_CS35L41_I2C_2, not ALC294_FIXUP_ASUS_ALLY.
• HDA internal mic pins exist:
  • 0x12: FL has voice, FR is railed/noisy.
  • 0x13: both channels are clean, voice confirmed, but lower level.
• ALSA Capture Source exposes 0 = Internal Mic and 1 = Internal Mic 1, but PipeWire/WirePlumber resets capture back to 0.

Help wanted:

• determine the proper upstreamable fix: Realtek HDA quirk, ALSA UCM, WirePlumber profile/rule, or deeper ACP/SOF/offload support;
• avoid shipping a simple ACP/PDM _WOV/machine-driver quirk unless the railed ACP capture path is also solved.