Linux 5.10 regression - manual fan control broken, causing critical temperatures on MSI RX 5700 XT Gaming

Brief summary of the problem:

Continuation of #1164 (closed)

Do

su
echo 1 > /sys/class/drm/card0/device/hwmon/hwmon3/pwm1_enable    # set fan control to manual
echo 70 > /sys/class/drm/card0/device/hwmon/hwmon3/pwm1    # set fan speed to 70 PWM cycles

Results:

Linux 5.9.14: Fans correctly spin up

Linux 5.10: Fans don't start spinning. Neither is the pwm1 value applied, nor does the card's default fan curve get applied. -> GPU gets very hot under load, probably can overheat. There is no error verbosity when applying the values via terminal to sysfs.

Attached files:

dmesg.log