Pi 3b+ and PoE hat not respecting fan temp settings in config.txt

couch-potato · June 16, 2020 at 12:18 PM

Don't think its just me having tried this on a second Pi...

I just upgraded a couple of my PoE powered Pi 3b+'s already fitted with PoE hats to 9.2.3. Everything seems to work as expected with the following exception...

The Pi appears to ignore the

Code

dtparam=poe_fan_temp0=65000,poe_fan_temp0_hyst=5000,poe_fan_temp1=67000,poe_fan_temp1_hyst=2000

entry in config.txt. the fans are still firing off at 50° not the 65° specified.

My previous LibreELEC release (9.2.1) worked exactly as expected with the fan cutting in at 65°

Any Ideas?

Thanks

**HiassofT** · June 16, 2020 at 12:49 PM

This sounds a bit like you may be running into the config.txt line-length limit. Try to break up the dtoverlay line as described here Reduce noise from rpi poe hat fan by Learath · Pull Request #3493 · raspberrypi/linux · GitHub

so long,

Hias

couch-potato · June 16, 2020 at 3:18 PM

OK, tried that...

config.txt now reads:

dtoverlay=rpi-poe

dtparam=poe_fan_temp0=65000,poe_fan_temp0_hyst=5000

dtparam=poe_fan_temp1=67000,poe_fan_temp1_hyst=2000

Fan is still kicking off at 50°

Kernel is 4.19.122 which should be ok according to Reduce noise from rpi poe hat fan by Learath · Pull Request #3493 · raspberrypi/linux · GitHub

Can't spot any typos and tried updating rpi-poe.dtbo for good measure, so have no idea whats happening here...

**HiassofT** · June 16, 2020 at 4:11 PM

I think I now know what's going on, you probably have to override 4 trip points instead of two.

There were two cooling zones added before the previously existing ones at slower fan rotation speeds.

So try adding temp2 and temp3 as well, like in the github discussion, I guess that should work.

so long,

Hias

couch-potato · June 16, 2020 at 7:42 PM

Thanks...

That seems to have fixed it - don' t like making changes like this obvious do they?

Cheers!

Couch

LuXxX · September 22, 2021 at 10:20 PM

Hello, I'm using RPi4B with PoE Hat and LibreElec 9.8.2.

Could you please output your mentioned config.txt outputs for all 4 zones?

Or is it different with RPi4B?

Thanks

LuX