Hello,

I have installed Slackware64 14.2, and want to control my fans through fancontrol, since the machine is really loud. The motherboard uses the 'it8620e' chipset which is supported by the 'it87' hwmon driver. Although, the stock slack kernel, nor aliens updated kernel do not have the updated 'it87.c' which provides control over 5 fan/pwm outputs. So I first tried to patch the 'it87.c' from the newer kernel (4.15.4) in order to get the support, since I'm using all the 4th and 5th fan header on the motherboard. The simptoms to which I will come in a moment still persisted, so I just went ahead and compiled the whole 4.15.4 kernel, which I am currently running.

So, now I am able to configure all my fans with 'pwmconfig' just fine, I set them up as I want them, save the config and start 'fancontrol', all fine. But, when I reboot and start fancontrol, then the fans on the 4th and 5th header immediatelly go to full speed, and PWM readout shows 255 on them. If I then kill fancontrol the fans on the other headers go to full speed, and fans on 4th and 5th stop completely.

I have to reboot without starting fancontrol, and re-run the pwmconfig, without configuring, just let it spin the fans down and up, then fancontrol works as intended again (until I reboot). Which meant that there must be something going on in pwmconfig that fixes this issue. After careful inspection, I saw that the files /sys/devices/platform/it87.2608/hwmon/hwmon2/pwm[1-5]_enable all contain the integer value 2. But pwm config echoes int(1) into them when spinning the fans up and down. So then I manually ran echo 1 2> /dev/null > /sys/devices/platform/it87.2608/hwmon/hwmon2/pwm5_enable (note, I did that only for pwm5), the fans on the 5th header immediatelly stopped. Then running 'fancontrol' again, regained the normal operation, all fans working just fine, even those on the 4th header.

So now, quite fed up with the situation, I though, simply add that "echo 1" to rc.local before the fancontrol start and be done with it, but nope, after reboot, the fans on 4th and 5th running at full speed again. But if I reboot, login normally, run that "echo 1" and start fancontrol then, everything is fine. Any idea what could cause this? Have I missed anything? Can I try anything to attempt to fix this?

Kind regards,
slax0r

I am an obsessed fiend about temperatures and have 6 fans in my Main. My mobo is an Asrock Z77 Extreme and BIOS gives me considerable control regardless of OpSys or kernel but I tend to have them running at or near full speed and depend on hardware for quietness, specifically larger, slower-turning fans designed for reasonable noise levels like Noctua

-- Ultra Low Noise, Hi Performance Fans --

It is more troublesome to replace the louder fans on my nVidia GTX 1070 Ti but the "coolbits" option and a startup script creates a balance I like.

I know this is not likely to be the fix you're looking for but it is at least an option that may achieve for you a highly desirable balance between performance and noise.

I'll offer empathy in that I always found fancontrol/pwmconfig to be frustrating. That said, look in the system's /etc/fancontrol. Often in my experience I end up manually tweaking that file. Possibly the min and max for fans 4 and 5 are incorrect. No need to reboot, changes in the file are effective immediately.

I have seen the hwmon[0-9] subdirectory change across reboots. That is, I might tweak for hwmon0 and after a reboot the path changes to hwmon1. I never dug deep into why because after I finally got the config I wanted I moved on to more productive things, like cleaning my belly button.

@enorbet: This is on my gaming rig, which sports a custom water cooling loop. The fans when under automatic control are spinning way too fast, I don't even need to run them when idling, that's why I want fancontrol, because, no spin, no noise.

@upnort: I've checked, the config file is completely fine. Fancontrol also works just fine, it sets the correct PWM value in the /sys/devices/platform/it87.2608/hwmon/hwmon2/pwm5 and /sys/devices/platform/it87.2608/hwmon/hwmon2/pwm4 files. When idle it puts 60 in 5 and ~95 in 4, which would mean a complete stop for 5 and very slow speed for 4, but for some reason, the fans on those headers go to near full-speed spin. Then I start "stress", put some load on the CPU to up the temps, fancontrol updates the PWM value of 5 to ~140, but the fans slow down.