No SoundWire machine driver match on Surface Laptop for Business 13" 1st Ed (Panther Lake) - unsupported RT718 SDCA codec (part id 0x718)

[SeanD6091]

Hardware

• Device: Microsoft Surface Laptop for Business 13" 1st Edition (Intel)
• DMI: Microsoft Corporation Surface Laptop for Business 13in 1st Ed Intel/Surface Laptop for Business 13in 1st Ed Intel, BIOS 7.4.143
• CPU: Intel Core Ultra 5 Processor 325 (Panther Lake)
• MPN: 90N421100680

Kernel

• 6.19.8-arch1-3-surface (linux-surface)
• Distro: CachyOS (Arch-based)

Symptom

No internal speaker or headphone playback device is created. Only HDMI/DP
outputs are exposed (aplay -l / PipeWire show three HDMI PCM devices and
nothing else). SOF itself loads and boots firmware correctly; the failure is
in SoundWire machine driver matching.

What I've confirmed

The DSP is detected and firmware boots fine, but no machine driver matches
the ACPI-reported SoundWire configuration:

• link 1, mfg_id 0x025d part_id 0x0721 version 0x3 (Realtek RT721 - has upstream driver)
• link 1, mfg_id 0x025d part_id 0x0718 version 0x3 (Realtek RT718 - appears to have NO upstream driver)
• link 3, mfg_id 0x025d part_id 0x1320 version 0x3 (Realtek RT1320 - has upstream driver)

Kernel explicitly logs part id 0x718 is not supported, after which it falls
back to the generic skl_hda_dsp_generic HDA-only machine driver, which only
exposes the HDMI/DP endpoints.

I searched for any existing RT718 SDCA codec driver (mainline or pending
patches) and could not find one, unlike RT721/RT712/RT766 which have drivers.
If I'm wrong and one exists, pointers welcome — otherwise this looks like a
genuinely new part that needs a driver, likely used for jack detection /
combo audio duties alongside the RT721 and RT1320 on this board.

Relevant dmesg

[    5.639047] sof-audio-pci-intel-ptl 0000:00:1f.3: enabling device (0000 -> 0002)
[    5.639204] sof-audio-pci-intel-ptl 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if 0x040100
[    5.639259] sof-audio-pci-intel-ptl 0000:00:1f.3: bound 0000:00:02.0 (ops intel_audio_component_bind_ops [xe])
[    5.645985] sof-audio-pci-intel-ptl 0000:00:1f.3: use msi interrupt mode
[    5.667141] sof-audio-pci-intel-ptl 0000:00:1f.3: No SoundWire machine driver found for the ACPI-reported configuration:
[    5.667144] sof-audio-pci-intel-ptl 0000:00:1f.3: link 1 mfg_id 0x025d part_id 0x0721 version 0x3
[    5.667145] sof-audio-pci-intel-ptl 0000:00:1f.3: link 1 mfg_id 0x025d part_id 0x0718 version 0x3
[    5.667146] sof-audio-pci-intel-ptl 0000:00:1f.3: link 3 mfg_id 0x025d part_id 0x1320 version 0x3
[    5.667149] sof-audio-pci-intel-ptl 0000:00:1f.3: part id 0x718 is not supported
[    5.667150] sof-audio-pci-intel-ptl 0000:00:1f.3: hda codecs found, mask 4
[    5.667151] sof-audio-pci-intel-ptl 0000:00:1f.3: using HDA machine driver skl_hda_dsp_generic now
[    5.667153] sof-audio-pci-intel-ptl 0000:00:1f.3: NHLT device BT(0) detected, ssp_mask 0x4
[    5.667154] sof-audio-pci-intel-ptl 0000:00:1f.3: BT link detected in NHLT tables: 0x4
[    5.667156] sof-audio-pci-intel-ptl 0000:00:1f.3: DMICs detected in NHLT tables: 0
[    5.669747] sof-audio-pci-intel-ptl 0000:00:1f.3: Firmware paths/files for ipc type 1:
[    5.669752] sof-audio-pci-intel-ptl 0000:00:1f.3:  Firmware file:     intel/sof-ipc4/ptl/sof-ptl.ri
[    5.669796] sof-audio-pci-intel-ptl 0000:00:1f.3:  Firmware lib path: intel/sof-ipc4-lib/ptl
[    5.669799] sof-audio-pci-intel-ptl 0000:00:1f.3:  Topology file:     intel/sof-ipc4-tplg/sof-hda-generic-idisp.tplg
[    5.670953] sof-audio-pci-intel-ptl 0000:00:1f.3: Loaded firmware library: ADSPFW, version: 2.14.1.1
[    5.943798] sof-audio-pci-intel-ptl 0000:00:1f.3: Booted firmware version: 2.14.1.1

Ask

Could an RT718 SDCA codec driver (and corresponding machine-driver match
entry for this link 1 RT721+RT718 / link 3 RT1320 combination) be added?
Happy to test patches or provide any further logs/ACPI dumps needed.