Pi5, original active cooler is not run after startup

[cankirca]

Hello,

Got RP 5, original case and active cooller.

1. downloaded DietPi from the website for RP5 and imaged a new SD card.
2. Restored my previous RP4 DietPi backup from USB drive.
   *All apps running as expected, however temprature is about 55°C right now, Fan is not running, system says warm but safe.
   *Fan runs at startup for few seconds and stops.
   *I didn't do for my previous Pi400 before, it was working best all the time.
   How can I set my fan settings to keep my RP5 cooller?
   Thank you.

[Joulinar]

Unfortunately, you have failed to fill in the troubleshooting template. Therefore we do not know which kernel is currently active. I assume that the restore of an RPi4 backup does not use the 2712-rpi-5 kernel.

Please go to dietpi-config > 4 : Advanced Options > RPi kernel choice and switch to the dedicated RPi5 kernel

[cankirca]

Hi @Joulinar, I thought that kernel is correct, here the output when I choose Rpi Kernel from the advanced menu:
"DietPi-Set_software
Based on your currently used kernel variant, the following package will be kept/installed:

• linux-image-rpi-2712 for Raspberry Pi 5 only
  Do you want to keep/install the following additional kernel package, to boot this image from other Raspberry Pi models?
• linux-image-rpi-v8 for Raspberry Pi 2-5
  <Yes/No"
  I choose no.
  Is that correct?
  Also advanced/Update RPi EEPROM firmware : [Bootloader: 1737505011 | VL805: N/A]
  BOOTLOADER: up to date
  CURRENT: Wed Jan 22 00:16:51 UTC 2025 (1737505011)
  LATEST: Wed Jan 22 00:16:51 UTC 2025 (1737505011)
  RELEASE: default (/usr/lib/firmware/raspberrypi/bootloader-2712/default)

[MichaIng]

So it is the RPi 5 kernel already. Yes you could uninstall the v8 kernel.

To enable the fan:

G_CONFIG_INJECT 'dtparam=cooling_fan=' 'dtparam=cooling_fan=on' /boot/config.txt
dtparam cooling_fan=on

Not sure whether the 2nd command enables it directly, or whether a reboot is requried.

[Joulinar]

If I am not mistaken, the fan control should already be active via the default settings in the firmware.

[MichaIng]

Correct: /boot/firmware/overlays/README

        cooling_fan             Enables the Pi 5 cooling fan (enabled
                                automatically by the firmware)

Hence nothing is required. It should turn on at 50°C IIRC.

Here is how to change the trip points permanently: #6676 (comment)