Fan pwm stopped working on Odroid HC4

[TheWorldOfCode]

Armbianmonitor:

https://paste.armbian.com/xusabacije

I have three identical Odroid HC 4 which has been running the same software and using the kernel 6.12.32-current-meson64. Their are configured as NAS where the data is split across all three devices and therefore their are running constantly. A couple of weeks ago began the fan on one of the machines behavior different. It would either be running a full speed or no running, it was no longer possible to control via PWM. Now last week did another one start with the same behavior.

 

I was do the following to test and validate the issue:

• I have disable the fancontrol service and manually written to hwmon2/pwm1 to set the PWM. Which was possible on the healthy HC4, but on the unhealthy HC4 would it only be full speed or no speed.
• I have tried the latest version of Armbian Noble and Trixie the hwmon2/pwm1 is exposed but doesn't allow me to modify the speed of the fan.
• I have tried the official os image from Hardkernel and here does the fan work as expected.

[tparys]

Can you post logs of both working and not working boards?

 

If they are exactly the same software, it sounds like a hardware issue.

 

If the HardKernel images works as expected, perhaps you've updated all 3, but not rebooted the working one yet?

[TheWorldOfCode]

Hi Tparys 

 

Sorry for the last reply, it has been a couple of busy days. 

 

> If they are exactly the same software, it sounds like a hardware issue. 

Yes that was my initial thought, and therefore I validated with the HardKernel images on one of broken nodes and since the PWM fan was a normal. It seems to be a software problem instead. 

 

> If the HardKernel images works as expected, perhaps you've updated all 3, but not rebooted the working one yet? 

After the second node broke have a turn all devices off each night and the healthy node has worked every day. 

 

> Can you post logs of both working and not working boards?

 

 

Node 1 (Healthy): https://paste.armbian.com/ibofokalis

 

Node 2 (Unhealthy): https://paste.armbian.com/ifihodukoj

I am reinstalled armbian 26.2.1 Noble and here is the PWM not working. I am capable of setting a PWM but it doesn't respond to it. 

It was on this node I have tested the HardKernel Image

Node 3 (Unhealthy): https://paste.armbian.com/kemesojuva

I have done some additional debug on this node. 

The hwmon2/pwm1_enable is set to 1 for manual mode and pwm1 is zero even if the fan is speeding at full speed. 

If I disable the fancontrol service and manually control the pwm1, it is possible to set the pwm to a different speed and the fan will respond but after a split sensor would the value of pwm1 be reset to 0 instead of the assigned value.  

 

 

 

[tparys]

From your logs:

 

Healthy: 6.12.32-current-meson64

 

Unhealthy: 6.18.15-current-meson64

 

Certainly sounds like something changed/broke in a major kernel update?

 

For the near term, I would grab a copy of the 6.12 kernel and keep a copy. The apt tool should have saved a copy in /var/cache/apt/archives, so you should be able to pull a copy from the good system, and use "sudo dpkg -i" to downgrade the other two boards for the time being. If the working node has been upgraded, it's fan will probably stop working as intended after a power cycle.

 

In parallel, the next thing to do is to take a look at the .dtb files for both kernels (amlogic/meson-sm1-odroid-hc4.dtb), and see what's changed. If I have a free evening, I'll take a peek.

 

As @Igor as the board maintainer, you can also file a bug at https://github.com/armbian/build/issues, but could be a bit to get addressed.

 

 

Edited 1 hour ago by tparys