ThinkPad X1 Carbon Aura Gen 13 — OpenBSD Support Proposal

Executive Summary

The ThinkPad X1 Carbon Aura Gen 13 (Intel Arrow Lake-U / Core Ultra 7 255U) has partial but usable support on OpenBSD -current as of late 2025. Based on actual testing (dmesg from Dec 30, 2025), core functionality works (boot, CPU, NVMe, audio, input), while key blockers remain (Wi-Fi init failure, GPU GuC firmware issues, Thunderbolt unattached). This document outlines the targeted engineering work to fix remaining issues, the testing methodology, and the contribution workflow for upstreaming changes to OpenBSD.

Hardware Inventory

Based on actual OpenBSD -current testing (Dec 30, 2025 dmesg, machine type 21NXCTO1WW, BIOS N4MET26W):

Component Chipset OpenBSD Status
CPU Intel Core Ultra 7 255U (Arrow Lake-U) Working — acpicpu(4) attaches, C-states, PSS, SpeedStep
GPU Intel Graphics (detected as Meteor Lake gen 12) Partial — modesetting works (1920x1200), GuC firmware init fails (“GPU wedged”), no acceleration
Wi-Fi Detected as Intel Wi-Fi 6e AX211 (likely BE-series) Broken — “could not initialize hardware”, clock stabilization timeout, APM init errors
Audio Intel Core Ultra HD Audio, Realtek ALC287 Working — azalia(4) attaches, audio0 created
NVMe SK hynix drive Working — attaches as sd0
Input Synaptics SYNA802E (I2C HID) Working — ihidev(4), clickpad, multi-touch, trackpoint
Keyboard Standard ThinkPad Working — pckbd(4), acpithinkpad(4) present
Ethernet — Not listed in dmesg (likely via USB-C dock)
Thunderbolt/USB4 USB4 / Thunderbolt bridges Partial — “not configured” in dmesg
Webcam — Not listed (likely MIPI, unsupported)
Sensors acpiec(4), ThinkPad EC Partial — basic EC present, thermal/battery functional
NPU/IPU/GNA Intel AI accelerators Unsupported — “not configured” (expected)
TPM TPM 2.0 Working
Power S0ix/S4/S5 ACPI states Partial — states recognized, real-world S0ix reliability untested
WWAN Quectel modem (optional) Untested — present but not configured

Actual Test Results (OpenBSD 7.8-current, Dec 30 2025)

Source: dmesgd.nycbug.org — Lenovo ThinkPad X1 Carbon Gen 13 (21NXCTO1WW, BIOS N4MET26W)

What Works:

  • Boot to multiuser, console at 1920x1200
  • CPU: Core Ultra 7 255U, 12C/14T, SpeedStep, C-states, PSS
  • Storage: SK hynix NVMe (sd0)
  • Audio: azalia(4) + Realtek ALC287, audio0 created
  • Input: Synaptics SYNA802E I2C trackpad (clickpad, multi-touch), keyboard, trackpoint
  • TPM 2.0, acpithinkpad(4), acpiec(4)
  • USB (xhci(4))

What Partially Works:

  • Graphics: Modesetting works, GuC firmware fails (“GPU wedged”), no acceleration
  • Power: S0ix states recognized, real-world testing needed
  • Thunderbolt/USB4: Present but “not configured”

What Fails:

  • Wi-Fi: Detected as AX211, “could not initialize hardware”, clock stabilization timeout
  • Webcam: Likely MIPI, not detected
  • NPU/IPU/GNA: “not configured” (expected)

Recommended Workarounds:

  • Wi-Fi: Use USB Wi-Fi dongle or USB-C Ethernet dock
  • Webcam: Use USB webcam

Driver Porting Tasks

1. inteldrm — Fix GuC Firmware and GPU Acceleration

Status: GPU detected as Meteor Lake gen 12, modesetting works, but GuC firmware initialization fails (“GPU wedged” taint).

Scope: Fix GuC firmware loading and enable GPU acceleration for Arrow Lake-U / Meteor Lake graphics.

Tasks:

  • Debug GuC firmware init failure (check firmware version in inteldrm, compare with Linux)
  • Update or add correct GuC firmware files for Meteor Lake/Arrow Lake
  • Fix GuC handshake and initialization sequence
  • Enable accelerated X11/Wayland support (blitter, rendering)
  • Test: glxinfo, suspend/resume, brightness control, external display

Constraints: ISC license only. No GPL code. Study Linux i915 GuC code for register definitions, rewrite independently.

2. iwx — Fix Wi-Fi Initialization (AX211/BE200)

Status: Card detected as “Intel Wi-Fi 6e AX211” but fails with clock stabilization timeout and APM init errors. Actual chip likely BE-series (Wi-Fi 7).

Scope: Fix firmware loading and initialization for the BE200/AX211 variant in this platform.

Tasks:

  • Identify exact chip via pcidump -v (likely 0x272b BE200 or 0x7af0 AX211)
  • Debug clock stabilization timeout (check firmware file, LAR disable, etc.)
  • Add/fix firmware definition (iwx-be200-*.ucode or correct AX211 firmware)
  • Test: ifconfig iwx0 scan, association, 2.4/5 GHz, throughput

Workaround: Use supported USB Wi-Fi dongle until fixed.

3. Power Management — S0ix Testing and Tuning

Status: ACPI reports S0ix/S4/S5 states, intelpmc(4) present. Real-world S0ix reliability untested.

Scope: Test and tune modern standby, validate battery life and thermals.

Tasks:

  • Test zzz (suspend) and ZZZ (hibernate) — collect success/failure logs
  • Monitor battery life under load vs. idle (compare with Linux)
  • Tune C-states and P-states if needed (sysctl hw.setperf, apm)
  • Port any missing Meteor Lake PCH power registers if S0ix fails
  • Test: wake from keyboard, network, lid open

4. Sensors — Validate and Enhance

Status: acpiec(4) present, basic EC/sensors functional. ThinkPad-specific sensors may need tuning.

Scope: Ensure thermal throttling, battery monitoring, and fan control work correctly.

Tasks:

  • Validate sysctl hw.sensors output (battery %, temp, fan RPM)
  • Test thermal throttling under load (apm -l, sysctl hw.sensors)
  • Add any missing ThinkPad-specific sensor hooks (acpithinkpad(4))
  • Test: fan behavior, critical shutdown temps

5. Audio — Already Working

Status: azalia(4) attaches with Realtek ALC287 codec, audio0 created. No SOF port needed.

No action required. If audio issues arise later, debug azalia not SOF.

6. Thunderbolt/USB4 — Attach Missing Driver

Status: “not configured” in dmesg. May need PCI ID additions or new driver.

Tasks:

  • Run pcidump -v to identify exact Thunderbolt/USB4 controller
  • Add PCI ID to appropriate driver (likely pcib(4) or dedicated Thunderbolt driver)
  • Test: Thunderbolt device hotplug, USB4 peripherals
  • Note: May require BIOS setting changes (disable “Security Level” if present)

7. Webcam — MIPI Camera Support

Status: Webcam likely MIPI (not USB UVC), unsupported by OpenBSD.

Tasks:

  • Confirm webcam type via usbdevs or pcidump
  • If USB: should work with uvideo(4)
  • If MIPI: Major undertaking (no MIPI stack in OpenBSD), use USB webcam as workaround

8. PCI ID Updates — NVMe, Ethernet

Status: NVMe works (SK hynix). Ethernet likely via USB-C dock (not built-in).

Tasks:

  • If Ethernet not detected: pcidump -v, add PCI ID to em(4) or igc(4)
  • NVMe: Should work, no action needed unless different controller found

Testing Methodology

Phase 0: Review Existing Data

Before testing, review the existing dmesg at dmesgd.nycbug.org (Lenovo X1 Carbon Gen 13, Dec 30 2025, BIOS N4MET26W). Compare your hardware (Aura Edition may have OLED, different Wi-Fi card, etc.).

Phase 1: Baseline Collection

On the target machine (boot latest OpenBSD -current snapshot):

dmesg > dmesg.txt
pcidump -v > pcidump.txt
sysctl hw > sysctl-hw.txt
acpidump -dt > acpi.aml
usbdevs -v > usbdevs.txt

Identify:

  • Which devices fail to attach (compare with existing dmesg)
  • Which attach but don’t function (e.g., Wi-Fi init failure)
  • Which work but lack features (power mgmt, acceleration, etc.)
  • Aura Edition specifics (OLED display behavior, etc.)

Phase 2: Incremental Driver Porting

  1. One driver at a time — don’t port inteldrm and iwx simultaneously
  2. Start with easiest — PCI ID additions before complex logic ports
  3. Test after each change — make in kernel build dir, reboot, verify
  4. Use ddb — kernel debugger for crash analysis (boot -d, trace, ps)

Phase 3: Regression Testing

After each driver works:

  • Run make regress in /usr/src/regress
  • Test on other Intel hardware to ensure no regressions
  • Document any new bugs introduced

Contribution Workflow

1. Development Environment

# OpenBSD -current system
cd /usr/src
cvs up -PAd
# Create branch for each driver
mkdir -p ~/patches/meteor-lake

2. Patch Submission

OpenBSD uses tech@openbsd.org mailing list for code review:

  1. Format patches with cvs diff -uNp
  2. Write clear commit messages — describe why, not what
  3. Include test results — dmesg before/after, functional tests
  4. Be responsive — address reviewer feedback promptly

Example patch header:

Add Intel Meteor Lake GPU support to inteldrm(4)

Tested on ThinkPad X1 Carbon Aura Gen 13 (Core Ultra 7 155H).
Display works at 1920x1200, suspend/resume functional.
X11 acceleration untested (TODO: implement blitter).

3. Licensing Requirements

  • All code must be ISC license or compatible
  • No GPL-licensed code or direct translations
  • Study Linux/FreeBSD drivers for register definitions only
  • Rewrite logic independently — clean-room implementation

4. Timeline Estimates

Based on actual hardware status (audio works, GPU partial, Wi-Fi broken):

Task Effort Dependencies
iwx Wi-Fi fix (firmware/clock) 2-4 weeks Firmware availability
inteldrm GuC fix + acceleration 1-3 months Firmware debugging
Thunderbolt/USB4 attach 1-2 weeks PCI ID addition
S0ix testing/tuning 2-4 weeks None (test existing support)
Sensors validation 1 week None (mostly works)
Audio Done N/A
Webcam (MIPI) 6-12 months Major undertaking (skip)
Full integration 2 weeks All drivers

Minimal working system (Wi-Fi + GPU accel): 2-4 months part-time Full feature parity (excluding MIPI webcam): 4-6 months part-time

For Non-Developers

If you cannot write kernel code:

  1. Sponsor a developer — contact OpenBSD developers willing to take contracts
  2. Provide hardware — ship the laptop to a developer for testing
  3. Test snapshots — regularly test -current and report dmesg diffs
  4. Document findings — maintain a test matrix of what works/fails
  5. Financial support — donate to OpenBSD Foundation earmarked for laptop support

Risk Assessment

Risk Impact Mitigation
GuC firmware init failure unfixable High Fallback to unaccelerated modesetting (currently works)
Wi-Fi firmware/clock issue persistent Medium Use USB Wi-Fi dongle or USB-C Ethernet
S0ix unreliable on Arrow Lake-U Medium Test thoroughly, use S3 if available in BIOS
Thunderbolt needs new driver (not just PCI ID) Medium USB-C dock for Ethernet/display
MIPI webcam (no OpenBSD support) Low Use USB webcam
OLED display issues (Aura Edition) Medium Test with LCD model first, report OLED-specific bugs
No developer interest High Financial sponsorship, hardware donation

Next Steps

  1. Review existing dmesg at dmesgd.nycbug.org (search “X1 Carbon Gen 13”)
  2. Boot latest -current snapshot, collect dmesg, pcidump -v, compare with existing reports
  3. Identify top 3 blocking issues: Wi-Fi init failure, GPU GuC firmware, Thunderbolt attach
  4. Start with Wi-Fi fix (highest impact, moderate effort) — debug firmware loading
  5. Set up OpenBSD -current build environment (cvs up -PAd)
  6. Begin with iwx debugging (firmware files, clock stabilization)
  7. Test S0ix (zzz/ZZZ) and document results
  8. Submit findings to dmesgd.nycbug.org and misc@openbsd.org

References

  • Existing dmesg: dmesgd.nycbug.org (search “ThinkPad X1 Carbon Gen 13”)
  • OpenBSD inteldrm source: /usr/src/sys/dev/pci/drm/i915/
  • OpenBSD iwx source: /usr/src/sys/dev/pci/if_iwx.c
  • Linux i915 driver: drivers/gpu/drm/i915/ (for register definitions, clean-room only)
  • Linux iwlwifi driver: drivers/net/wireless/intel/iwlwifi/ (for Wi-Fi firmware reference)
  • OpenBSD man pages: inteldrm(4), iwx(4), azalia(4), acpisleep(4)
  • Mailing lists: tech@openbsd.org, misc@openbsd.org (subscribe via majordomo@openbsd.org)
  • OpenBSD laptop compatibility: jcs.org/openbsd-laptops
  • NYC*BUG dmesg collection: dmesgd.nycbug.org

This proposal is a living document. Update as hardware testing progresses and drivers are implemented.