Microphone on ThinkPad X1 Carbon Gen 14 (Panther Lake + CS42L45) silent — missing sof-ptl-cs42l45 topology / machine driver

[ocewers]

System details

Lenovo ThinkPad X1 Carbon Gen 14 - 21V7CTO1WW

What's wrong?

Summary

On Lenovo ThinkPad X1 Carbon Gen 14, the integrated microphone delivers only silence (all-zero samples) under Omarchy. SOF detects the Cirrus Logic CS42L45 codec on SoundWire link 2 and CS35L56 speaker codec on link 3, but no SoundWire machine driver matches this combination on Panther Lake, so SOF falls back to a generic "default machine driver with function topologies" which does not produce real capture data.

This is a companion issue to #6000 (camera). Both Gen 14 problems trace to Panther Lake support gaps that don't affect Dell XPS PTL because XPS uses a different codec set (CS42L43, which has full topology coverage).

Hardware / system

• Machine: Lenovo ThinkPad X1 Carbon Gen 14 (21V7CTO1WW)
• CPU: Intel Core Ultra X7 368H (Panther Lake)
• Audio: Intel SOF sof-audio-pci-intel-ptl (PCI 8086:e428)
• SoundWire codecs detected:
  • link 2: mfg_id 0x01fa part_id 0x3563 — Cirrus Logic CS42L45 (mic/headset)
  • link 3: mfg_id 0x01fa part_id 0x4245 — Cirrus Logic CS35L56 (speaker amp)
• Omarchy: 3.8.2
• Kernel: tested linux 7.0.9-arch2-1 and linux-ptl 7.0.9-arch1-1-ptl
• sof-firmware 2025.12.2-1, alsa-ucm-conf 1.2.15.3-1

Symptoms

Card identifies correctly:

$ cat /proc/asound/cards
 0 [sofsoundwire   ]: sof-soundw
                      LENOVO-21V

PipeWire exposes sof-soundwire e, mapped to hw:sofsoundwire,4. Both PipeWire and direct ALSA c S16_LE -r 48000 -c 2) read
successfully but return only zering the raw capture file:

$ od -An -vtu1 /tmp/mic-hw4.raw wc -l
1                    # all bytes

Root cause (from kernel log)

sof-audio-pci-intel-ptl 0000:00:iver found for the ACPI-reported
configuration:
sof-audio-pci-intel-ptl 0000:00:part_id 0x3563 version 0x3
sof-audio-pci-intel-ptl 0000:00:part_id 0x4245 version 0x3
sof-audio-pci-intel-ptl 0000:00:achine driver with function
topologies
sof-audio-pci-intel-ptl 0000:00:ction topologies

The fallback path doesn't wire trectly. Looking at
`/usr/lib/firmware/intel/sof-ipc

• sof-ptl-cs42l43-* topologies
• sof-ptl-dmic-* topologies ex
• **No sof-ptl-cs42l45-* topolfirmware tree
• alsa-ucm-conf does ship a `c can't help without a matching
  kernel machine driver + tplg

Existing upstream report:
thesofproject/linux#5770 — "No
microphone capture on ThinkPad X) — cs42l45 PDE 11 event failed:
-110, missing sof-ptl-cs42l45 to

What I've tried

• Switched between linux and `ms.
• Verified codecs are detected o
• Captured directly from `hw:0,4Jack In) — both return all-zero
  samples.
• Confirmed PipeWire routing is iFi__Mic__source→hw:sofsoundwire,4`).

Suggested fix

This is fundamentally an upstrea35L56 + Panther Lake machine
driver + matching topology). Unt

1. Track [thesofproject/linux#57project/linux/issues/5770) andpull a patched sof-firmware on is published.
2. Add the machine driver patch patch exists.

Happy to test patches on this hardware and help out to make sure Omarchy works on this laptop!

[ocewers]

Seems Lenovo and Cirruc Logic is working on fixing this according to discussion in this thread on Reddit: ark: https://www.reddit.com/r/thinkpad/comments/1t109j0/linux_support_on_the_x1_carbon_gen_14/

[mrhpearson]

I'm guessing you need a BIOS update - can you let me know which version you are using please?
I'll check next week when back home which version you need - but microphone should work and all the pieces are upstream for that now.

[ocewers]

@mrhpearson I tried Update->Firmware, but lvfs detect no updates on the BIOS firmware. I'm running N4OET47W (1.10) and seems 1.16 is available, but nothing on microphone according to the change log. Can try updating any how to see if I get any improvement. Would be great if the update is available through lvfs though.

[ocewers]

@mrhpearson my bad, had the lid closed which prevented it to update. Now through Update->Firmware I got N4OET49W (1.12), solved the microphone issue. Closing this issue now.