Dear Maintainer,
# Debian Bug Report: SOF Audio Driver Regression on Intel Comet Lake
## Package
linux-image-6.12.48+deb13-amd64
## Severity
Important (hardware not working without manual intervention)
## Bug Summary
Audio device fails to initialize with SOF driver on Intel Comet Lake hardware in Debian 13 (kernel 6.12.x), requiring manual kernel parameter to force legacy HDA driver. This is a regression from Debian 12 where audio worked out of the box.
## Full Description
Subject: SOF driver fails on Intel Comet Lake PCH-LP cAVS - CSE_IPC_RESET_PHASE_1 timeout
The SOF (Sound Open Firmware) audio driver fails to initialize on Thinkpad X1 Yoga Gen 5 with Intel Comet Lake audio hardware after upgrading from Debian 12 (Bookworm) to Debian 13 (Trixie).
**Hardware:**
- Device: Thinkpad X1 Yoga Gen 5
- Audio Controller: Intel Comet Lake PCH-LP cAVS
- PCI ID: 8086:02c8
- Subsystem: Lenovo 17aa:22d7
**Issue:**
After fresh installation of Debian 13 Trixie, no audio devices are detected. Only dummy "auto_null" sink appears in PipeWire/PulseAudio. The kernel attempts to load the SOF driver (sof-audio-pci-intel-cnl) but fails with timeout errors.
**Kernel Errors:**
```
sof-audio-pci-intel-cnl 0000:00:1f.3: error: extended rom status: 0x0
sof-audio-pci-intel-cnl 0000:00:1f.3: error: CSE_IPC_RESET_PHASE_1 timeout
sof-audio-pci-intel-cnl 0000:00:1f.3: error: wl-dsp-core-reset-assert: timeout on HDA_DSP_REG_ADSPCS_CRST, target: 0x1 value: 0x0
sof-audio-pci-intel-cnl 0000:00:1f.3: error: dsp core reset failed: -110
sof-audio-pci-intel-cnl 0000:00:1f.3: error: failed to reset DSP
sof-audio-pci-intel-cnl 0000:00:1f.3: error: sof_probe_work failed err: -110
```
The driver makes 3 boot attempts, all failing with the same CSE (Converged Security Engine) IPC timeout.
**Working Configuration (Debian 12 Bookworm):**
Audio worked perfectly on the same hardware with Debian 12 using kernel 6.1.x series. The system likely used the legacy snd_hda_intel driver automatically.
**Workaround:**
Audio can be restored by forcing the legacy HDA driver with kernel parameter:
```
snd_intel_dspcfg.dsp_driver=1
```
Added to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub, followed by update-grub and reboot.
After applying this parameter:
- snd_hda_intel driver loads successfully
- Audio devices detected properly (aplay -l shows devices)
- PipeWire/PulseAudio detect hardware sinks correctly
- Audio playback works normally
**Expected Behavior:**
The SOF driver should either:
1. Work correctly with Intel Comet Lake hardware (preferred), OR
2. The system should automatically fall back to the legacy HDA driver when SOF initialization fails, OR
3. Intel Comet Lake devices should default to legacy HDA driver given known compatibility issues
**System Information:**
- Distribution: Debian 13 (Trixie)
- Kernel: 6.12.48+deb13-amd64
- Architecture: amd64
- firmware-sof-signed package: (check version with: dpkg -l | grep firmware-sof)
**Reproducibility:**
100% reproducible on fresh Debian 13 installation on Thinkpad X1 Yoga Gen 5.
**Impact:**
This affects all users upgrading from Debian 12 to Debian 13 with Intel Comet Lake audio hardware. Without the workaround, the system has no audio capability.
**Suggested Fix:**
Consider adding Intel Comet Lake (PCI ID 8086:02c8) to the quirks list to default to legacy HDA driver instead of SOF, similar to how other problematic devices are handled in snd_intel_dspcfg module.
**Additional Information:**
The CSE_IPC_RESET_PHASE_1 timeout suggests a communication failure between the SOF driver and Intel's Management Engine / Converged Security Engine. This may indicate:
- SOF firmware incompatibility with Comet Lake
- Kernel regression in ME/CSE communication
- Hardware initialization timing issues in kernel 6.12.x
The legacy HDA driver works perfectly, suggesting the hardware itself is functional and the issue is specific to the SOF driver implementation or firmware.