zenbook-duo: IIO sensors vanished after reboot — iio-sensor-proxy finds no sensors, ntm rotation blocked

[mecattaf]

2026-07-12 (pre-reboot): ntm probe saw /sys/bus/iio/devices/ with accel_3d, als, and hinge (plus their triggers).
2026-07-13 (post-reboot): /sys/bus/iio/devices/ does not exist. iio-sensor-proxy (now enabled via hardware.sensor.iio.enable = true, caa9ae9) starts and immediately exits: "No sensors or missing kernel drivers for the sensors".

Observed: hid_sensor_hub and intel_ishtp_hid/intel_ish_ipc ARE loaded (sensor hub enumerated), but the IIO client drivers (hid_sensor_accel_3d etc.) are not — count 0 in lsmod. A sudo modprobe hid_sensor_accel_3d hid_sensor_als hid_sensor_custom_intel_hinge over batch ssh hung and was killed; unresolved whether the modules are absent from the kernel build or failed to bind.

Investigation checklist

• modprobe hid_sensor_accel_3d interactively; check modinfo to confirm the module exists for the running kernel
• Compare kernel version/config between yesterday's generation and today's (ls /nix/var/nix/profiles/system-*-link/kernel) — did the rebuild change kernels?
• dmesg | grep -i -E "ish|sensor" for ISH firmware load failures (known flaky enumeration on ASUS ISH at cold boot)
• Cold reboot vs warm reboot behavior
• If it's a boot race: boot.kernelModules = [ "hid_sensor_accel_3d" ... ] on hosts/zenbook-duo as the declarative fix

Impact: ntm's rotation half is inert without this (net.hadess.SensorProxy never activatable). Gestures unaffected. Related: caa9ae9, ntm repo docs/DECISIONS.md.