Skip to content

Commit

Permalink
Make rpi poe fan less noisy in cool environments
Browse files Browse the repository at this point in the history 
Run the PoE hat fan with reduced noise when possible. The PoE hat fan will spin even at PWM=1 and spins almost silent. Tested at 17ºC, the fan PWM alternates between 1 and 10, which is a lot less noisy then alternating between PWM levels 0 and 31.
  • Loading branch information
@ProBackup-nl @pelwell
ProBackup-nl authored and pelwell committed Mar 22, 2021
1 parent 6c301bb commit dcf5c17
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/arm/boot/dts/overlays/rpi-poe-overlay.dts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
cooling-min-state = <0>;
cooling-max-state = <4>;
#cooling-cells = <2>;
cooling-levels = <0 31 63 150 255>;
cooling-levels = <0 1 10 100 255>;
status = "okay";
};
};
Expand Down

1 comment on commit dcf5c17

@Maxzillian
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This may work well on an idling Pi, but under some load it causes the fan to cycle between near silent and audible across the room. I'm using a pi4 with the PoE hat along with a skived copper heatsink. Along with a 2 GHz overclock these settings cause it to cycle between 10 (near silent) to 100 (very audible) on under a minute interval. Ultimately I had to change the settings for my system to 0, 40, 60, 100, 255 to maintain the necessary cooling without bumping up to 100 very often.

I think this points to the need that perhaps we need to be able to adjust the cooling levels like we can currently set the temperature thresholds and hysteresis.

Please sign in to comment.