RX580 fans always on on LInux while remain disabled on Windows 10

[Piotr Karbowski]

Hi,

I am running vanilla 4.18 kernel and I noticed that whenever I boot Windows 10, the card fans are off, unless I start to utilize the GPU. On Linux however the fans are always on around 400-800 rpm, while card takes about 36W according to sensors interface.

I can manually force the fan speed via sysfs interface, however it seems that I cannot disable them, also, after I change fan speed manually and then re-enable PWM, I see weird sound from the card/fans, up until I again set fan speed manually. When PWM is enabled I get the same 400-800rpm speed that I manually set. So the PWM is really only usable after reboot.

Is there a way to make it Windows-like? So the card is passive until it gets too hot.

The card I am running is the Sapphire RX 580 Nitro+ 8 GB DDR5. It has the stock bios with 1411 MHz core.

This is how hwmon interface looks after startup:

/sys/class/drm/card0/device/hwmon/hwmon0/*
fan1_input:778
in0_input:750
in0_label:vddgfx
name:amdgpu
power1_average:35154000
power1_cap:175000000
power1_cap_max:175000000
power1_cap_min:0
pwm1:43
pwm1_enable:2
pwm1_max:255
pwm1_min:0
temp1_crit:94000
temp1_crit_hyst:-273150
temp1_input:28000

if I touch `pwm1` and after that send `2` to `pwm1_enable` I will get weird noise from card, even that the rpm of fan is the same as it was when I set it manually via pwm1.

Thanks in advance for any hints

-- Piotr.