For the past month or so with the latest BIOS-Firmware I noticed that the thinkpad_acpi or the firmware is no-longer disabling the fan when the device enters standby mode aka. suspend to RAM.

This is very annoying when putting the device in a bag.

Workaround

I found a workaround with the zcfan software.

I use this configuration under /etc/zcfan.conf while the device is running:

max_temp 85
med_temp 75
low_temp 63
temp_hysteresis 10

This keeps the device just under 60°C with light operations and keeps the fan noise down after compiling.

Before the suspend to RAM I have to restart zcfan which then stops the fan for the suspend to RAM. After waking up it starts it again and protects the hardware.

Today, the new linux-image-6.1.0-20-amd64 was released so we will see if that one fixes the issue.

Side note

My X1 is equipped with an intel i7-1355U and yet, the hottest part is the area around the USB-C ports during charging.