Recognizing and coping with corrupted Embedded Controller states

in linux, embedded-controller, fedora, asus, acpi, asus-nb-wmi, kernel-update, zenbook, mental-health, note-to-self

I experienced weird issues on two different laptops (one AMD, one Intel) that I pinpointed to corrupted EC/ACPI firmware state.

The Root Cause

The most likely root cause is a bug somewhere in the kernel, the sensors subsystem, or the ACPI/WMI implementation for this hardware. The trigger I identified was having GNOME extensions installed that continuously poll hardware sensors (CPU frequency, GPU frequency, battery status etc). Those reads go through asus_wmi, which communicates with the EC — and something in that chain causes the EC to eventually enter a corrupted state.

The only way to recover from this state is still to power drain/cycle the laptop: hold power button for 60+ seconds while no psu is connected. This resets the EC firmware.

Stumbling on The Fix

Totally unrelated and while researching some other issue, I glanced at the title of a thread that suggested that lm_sensors may glitch out after waking from suspend.

This inspired me to simply turn off the extensions that keep hammering the EC (probably via asus_nb_wmi) for information and since then I have not experienced the issue anymore.

I will update this post if I experience it again but for now, disabling those extensions eliminated the issue for me.

As a bonus on my Intel platform, I can use 120 Hz refresh rate now without constant screen flickering.

Symptoms of EC / ACPI state corruption on Linux

I wrote two posts which I have now deleted since I found the root cause but I keep the summary of symptoms here for future reference.

• Extremely slow reboots, LUKS passphrase screen takes over a minute to appear
• Slow or failed wake from suspend
• Choppy boot-screen spinner (>20 s) — reliable early warning
• Choppy login screen animation
• Touchpad dropping inputs or completely unresponsive
• No audio, only "dummy output" in PulseAudio / PipeWire
• Fn / keyboard hotkeys (brightness, volume) freeze the system for ~10 seconds
• Keyboard backlight unresponsive
• Howdy face-recognition login stops working
• Erratic CPU frequency scaling, general slowness
• Sensors unavailable, GPU settings gone, Wayland instability
• Connectivity issues
• dmesg produces no helpful output during freezes (fault is below the kernel, in EC firmware)