When a certain temperature is reached, the fans usually turn on. Is there a temperature at which the fans become more active?
My guess is that some background process does something minor on a regular basis, which raises the temperature just slightly above the threshold, causing the fans to spin up until the temperature drops.
Embedded controller (updated with BIOS updates) decides at what conditions fan works with certain speed (fan curve). It works above/independently from linux, unless you force different fan speed. I see two possibilities:
BIOS update updated fan curve in embedded controller, Dell could restore old behaviour, but probably won’t;
laptop runs hotter, few possible reasons here:
radiator or fan vent is somehow blocked and needs cleaning
thermal compound dried up and is less effective in transferring heat
I’m guessing the BIOS has been updated automatically, but I don’t remember installing it.
The laptop did not run hotter, as I’ve monitored the temps as described in the last comment.
I’ve also tried installing the oldest kernel available for Fedora 37, the problem still persists, so I can confirm it’s not the kernel’s fault.
All in all, the cause is most certainly the BIOS has been updated and I did not realize it. Nevertheless, I have it kinda worked around it with i8kutils, although I cannot turn on Secure Boot if I use it, but it’s not a big deal for me.
I’d try clean F36. Anyway, my post shows possible reasons, you can cross them out one by one.
Dell provides some BIOS changelogs, check them.
With fwupdmgr get-history you can check bios upgrade history, more info about that and downgrade process (you might need to allow it in BIOS) in fwupdmgr -h.