Fan won't stop Aetina AN110

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
#1

Hello,
I have a Jetson NX with this Aetina AN110 Career board, and i can’t get my fan to stop. Rebooting the board won’t change anything.
Running tegrastats (to get the temperature of the board) gives me :

AO@22C GPU@23C PMIC@100C AUX@23C CPU@24C thermal@23.3C

I can’t use

sudo jetson_clocks --restore

since i didn’t do

sudo jetson_clocks --store

I saw that it could be related to a wrong device tree, but i don’t know how to check if this is the issue.
Any help would be appreciated.

#3

hello Bazziil,

it’s Thermal Management for enabling the fan to cool-down the chip.
there’s pwm settings to control fan, you may have a try to program it through sysnode.
for example, # echo [value:0-255] > /sys/class/hwmon/hwmon2/cur_pwm
please also refer to pwm_rpm_table for a look-up table to use PWMs for controlling fan rpm,
thanks

#4

Hi JerryChang,
Sorry for late reply,
I get the permission denied error with :
sudo echo 128 > /sys/class/hwmon/hwmon2/cur_pwm
I also can’t save this file after editing it with nano.
As i mentioned, the issue probably comes from the device tree, do you have any guide or documentation on how to manage device tree ?

#5

hello Bazziil,

so you’re actually working with Jetson Nano? I’m moving this topic to Nano series, thanks

#6

hello Bazziil,

you may check tegra_pwmfan for the sysnode for hardware monitor,

$ cat hwmon*/name
thermal-fan-est
tegra_pwmfan

it’s hwmon1 for Nano platform.
for example,

/sys/class/hwmon/hwmon1$ ls *pwm
cur_pwm  target_pwm
#7

so you’re actually working with Jetson Nano? I’m moving this topic to Nano series, thanks

I should have been clearer, i meant nano the file editor, like

sudo nano sys/class/hwmon/hwmon2/cur_pwm

Result of cat hwmon*/name :
thermal-fan-est
pwm_tach
tegra_pwmfan
soctherm_oc

I only have target_pwm and cur_pwm in hwmon2 out of hwmon0/1/2/3
I can edit the file and the pwm value seems to be taken correctly (if i set target_pwm to 120, cur_pwm will be 120). But i don’t notice speed change to the fan.

#8

hello Bazziil,

I see, may I have your confirmation of which Jetson platform you’re working with?
there’s pwm_rpm_table you may refer to, it shows the look-up values for RPM and PWM.
thanks

#9

Hello JerryChang,
Thanks for fast reply,
I’m working on the Jetson NX with this Aetina AN110 Career board
I’m on Jetpack 4.5 on Ubuntu 18.04 LTS

#10

okay, I am moving this to Jetson Xavier NX series,

#11

According to pwm_rpm_table, setting pwm to 0 should stop the fan, but it doesn’t work.
I really suspect that the device tree or the drivers is the cause of the issue since cur_pwm get the correct value.
How can i check this ?

#12

hello Bazziil,

did you check this by reading cur_pwm to ensure setting has applied?
this may be an issue with carrier board, please also contact with them for further investigation.
thanks

#13

Hello JerryChang,

did you check this by reading cur_pwm to ensure setting has applied?

Yes, i put 120 then 0 in :

sudo nano /sys/class/hwmon/hwmon2/target_pwm

Verifying the correct value in cur_pwm with :

sudo nano /sys/class/hwmon/hwmon2/cur_pwm

It’s was 120 then 0, fan speed did not change.

please also contact with them for further investigation.

I have done it, i will try to keep you informed. Thanks for your time

#14

hello Bazziil,

you may also refer to the kernel drivers for fan control.
for example,
$L4T_Sources/r32.5/Linux_for_Tegra/source/public/kernel/kernel-4.9/drivers/hwmon/pwm-fan.c

#16

Hello JerryChang,
I couldn’t find that file can you point me where it is ?

#17

hello Bazziil,

please download L4T Driver Package (BSP) Sources package, you shall find kernel drivers for fan control.
thanks

#18