teythoon

I found a Product Change Notification in the Kobol wiki that may be of interest: https://wiki.kobol.io/helios4/files/pcn/Helios4_PCN_201906060001.pdf > All Helios4 rev 1.2 and further will be using the new ARMADA 388 Rev-2.1 SoM. I haven't looked at the board, but I bought my Helios in 2018, so I'm pretty sure that it uses the ARMADA 388 Rev-2.0 SOM.

Thanks for looking into this, and sorry for the late response. > I just tested this on my helios4 with linux kernel 5.15.80 and both pwm controllers work just fine. Odd. > Have you tried going back to make sure it is not a HW problem? Or tried swapping fans around? > > Also make sure your /dev devices symlink to the correct path: Yes, I went back to the kernel provided by the package linux-image-legacy-mvebu which AFAICS is roughly the same version as was used with Buster-based Armbian. Going back immediately fixed the problem. The symlinks look fine. helios4# uname -r 4.19.167-mvebu helios4# ls -l /dev/fan* lrwxrwxrwx 1 root root 42 Jan 8 16:13 /dev/fan-j10 -> /sys/devices/platform/j10-pwm/hwmon/hwmon3 lrwxrwxrwx 1 root root 42 Jan 8 16:13 /dev/fan-j17 -> /sys/devices/platform/j17-pwm/hwmon/hwmon4 > So you'd need to provide more info on how you built your kernel version to get to this problem. First I installed the kernel from the stock Armbian package linux-image-current-mvebu. Then, after noticing the problem, I built the kernel images from Armbian master to make sure the problem still persists. And it did. I did not change the configuration or add patches during my build, I mostly tried to see whether the patch was indeed in.

After upgrading to the 5.15 kernel, I noticed that the fan control is only able to control one of the fans, while the other spins at full speed. Experimentally I found out that the PWM control for the second fan is ineffective: helios4# uname -r 5.15.86-mvebu helios4# echo 0 > /dev/fan-j10/pwm1 # works, fan is off helios4# echo 255 > /dev/fan-j10/pwm1 # works, fan at full speed helios4# echo 0 > /dev/fan-j17/pwm1 # does nothing, full speed helios4# echo 255 > /dev/fan-j17/pwm1 # does nothing, full speed Some digging around I found that 92-mvebu-gpio-remove-hardcoded-timer-assignment.patch has been ported to 5.15, but it doesn't seem to work for me.