[Question] What makes it impossible for the fan speed to go below 4%?

[RicArch97]

I found this to be a bit annoying, since as you know, on AMD Adrenaline in Windows you can enable Zero RPM where the fans don't spin when the card temperature is below 50C. This is also the case with the default auto settings of the card.

[mcgillij]

There was/is a driver bug on some cards: https://gitlab.freedesktop.org/drm/amd/-/issues/1164 I only have a Vega64 and a 6800xt to test with and I haven't been able to reproduce it on those.

You could comment out the 2 lines here: https://github.com/mcgillij/amdfan/blob/089f987c3cedb9192e96856ab24537b0b4eb2592/src/amdfan/amdfan.py#L284 if you wanted to try to reproduce it.

[mazunki]

Just did some measurements myself, seems like it depends on the hardware used. Maybe we should change it from a ValueError to a LOGGER.debug?

fan_path='/sys/class/drm/card0/device/hwmon/hwmon6/pwm1'
sudo=doas
for speed in $(seq 0 20); do printf "${speed}" | "${sudo}" tee "${fan_path}" >/dev/null; sleep 1; printf 'assigned: %2d => measured: %2d\n' "${speed}" "$(< "${fan_path}")"; done

[mcgillij]

Yeah it was a hardware limitation at the time, it's been several years since I've had to work around it. So it could be partially resolved at this point.