Arrow Lake-HX (Core Ultra 9 275HX) SOF firmware fails with error 0x97 - CS35L56 amplifiers non-functional

[jiranyi]

BUG REPORT

Arrow Lake-HX (Core Ultra 9 275HX) SOF firmware fails with signature validation error
0x97 - CS35L56 amplifiers non-functional

Environment
Laptop: Lenovo ThinkBook 16p G6 IAX (Model 21R0)
CPU: Intel Core Ultra 9 275HX (Arrow Lake-HX, Family 6, Model 198)
Audio Codec: Realtek ALC287 (Subsystem 0x17aa3921)
Amplifiers: Cirrus Logic CS35L56 x2 (I2C: CSC3556:00)
Kernel: 6.14.0-36-generic
linux-firmware: 20240318.git3b128b60-0ubuntu2.21
BIOS: Lenovo (up to date via fwupd)

Problem Description
The SOF (Sound Open Firmware) driver fails to load on Arrow Lake-HX laptops with
cryptographic signature validation error 0x97. This prevents the CS35L56 smart amplifiers from
functioning, resulting in either no audio or severely degraded audio quality. You'll find /tmp/alsa-info.txt attached.

alsa-info.txt

Error Log
[
4.849077] sof-audio-pci-intel-mtl 0000:80:1f.3: Firmware file: intel/sof-
ipc4/arl-s/sof-arl-s.ri
[
7.853974] sof-audio-pci-intel-mtl 0000:80:1f.3: 0xd000000c: module:
ROM_EXT, state: VALIDATE_PUB_KEY, not running
[
7.853982] sof-audio-pci-intel-mtl 0000:80:1f.3: error code: 0x97 (unknown)
[
7.854037] sof-audio-pci-intel-mtl 0000:80:1f.3: error: failed to boot DSP
firmware -110

Root Causes Identified

1. Missing signed firmware: The /lib/firmware/intel/sof-ipc4/arl/intel-
   signed/ directory is empty in current linux-firmware packages. Arrow Lake requires
   signed firmware for DSP validation.
2. Platform misdetection: Driver loads arl-s (Arrow Lake-S desktop) firmware instead of
   proper mobile platform firmware.
3. Codec confusion: HDA codec reports as "Intel Meteor Lake HDMI" (vendor 0x8086281d)
   despite Arrow Lake-HX CPU, suggesting BIOS/firmware platform identification issues.
   Impact
   • No working audio path to CS35L56 amplifiers - These require SOF topology for I2S/ASP
   routing• Fallback HDA driver produces tinny sound - Uses analog codec path instead of digital
   amplifier path
   • Affects all Arrow Lake-HX laptops with similar audio configurations

Attempted Workarounds

1. Symlink MTL firmware to ARL path
   ✗ Error 0x97 persists (signature mismatch)
2. Use unsigned ARL firmware
   ✗ Error 0x97 (DSP requires signed firmware)
3. Blacklist SOF, use legacy HDA
   ✓ Partial - audio works but quality poor
4. Kernel parameter snd_sof.tplg_path=
   ✗ Ignored by driver
5. Update BIOS via fwupd
   ✗ No updates available

Required Fixes
Short-term (Critical):

1. Release intel-signed firmware for Arrow Lake to linux-firmware repository
   • Path: intel/sof-ipc4/arl/intel-signed/sof-arl.ri.zst
   • Or clarify if ARL-HX should use MTL signed firmware

Medium-term:
2. Fix platform detection - Distinguish between arl-s (desktop) and arl-h/arl-hx
(mobile)
3. Add topology file for Lenovo ThinkBook + CS35L56 configuration
• Device: sof-arl-cs42l43-l0-cs35l56-l23.tplg exists but isn't loaded

Long-term:
4. Document Arrow Lake-HX audio requirements for OEMs and distros

Additional Information
• Full ALSA diagnostic attached: alsa-info.txt
• CS35L56 amplifiers ARE detected: cs35l56-hda i2c-CSC3556:00 shows in dmesg
• ACPI DMI: sys_vendor: LENOVO, product_name: 21R0

Questions for Intel SOF Team

1. Is Arrow Lake-HX supposed to use signed firmware? (error 0x97 suggests yes)
2. Should ARL-HX use arl, arl-h, or arl-s firmware directory?
3. Is intel-signed ARL firmware blocked by NDA or coming in future release?

Thank you for you help,
kind regards :)

[kv2019i]

@jiranyi This system uses the sof-arl-s.ri binary (kernel driver knows the correct firmware file to load). This is a bit confusing at times, but the firmware filename is named after the lead platform (that first used the DSP hardware generation). Intel signed binaries for this system have been available since v2.9 which was part of binary release https://github.com/thesofproject/sof-bin/releases/tag/v2024.03 . Distributions pick sof-bin releases as a separate package as we don't want to flood linux-firmware with the DSP topology files (that are distributed alongside the FW binary). These should have been picked by most distributions:

https://src.fedoraproject.org/rpms/alsa-sof-firmware
https://archlinux.org/packages/extra/x86_64/sof-firmware/
https://packages.debian.org/source/unstable/firmware-sof
https://packages.ubuntu.com/source/noble/firmware-sof

Let us know if the signed sof-arl-s.ri binary does not load. 0x97 is an authentication fail, so the signing key does not match the system. This error is expected if you copied some other FW file on top of sof-arl-s.ri.