Fan stop

[Kenzyss]

Checklist

• The problem is not listed in the hardware support matrix as a known limitation
• I've included a debug snapshot if the issue is related to hardware configuration

Bug description

LACT-sysfs-snapshot-20240731-181915.tar.gz
If you lower the fan speed slider to 0, the fans do not stop, but operate at minimum speed. If you enable automatic fan control, they stop (up to a certain temperature). Perhaps this is not a bug, but an unimplemented feature

System info

- LACT version: 0.5.5 release
- GPU model:AMD RADEON RX 6800 XT
- Kernel version: 6.9.12-lqx1-1-lqx
- Distribution: Arch

[ilya-zlobintsev]

Do they actually not stop physically, or just reported at a speed above 0? It's pretty common that 0 RPM isn't measured correctly by the GPU whem using a custom curve, while actually working fine.

[Kenzyss]

Do they actually not stop physically, or just reported at a speed above 0? It's pretty common that 0 RPM isn't measured correctly by the GPU whem using a custom curve, while actually working fine.

They don't physically stop. In corectrl there is something like fan stop, the statistics say 0 rpm, but in reality the fans are still working

[ilya-zlobintsev]

If you set it to 0 RPM, but it doesn't actually stop (and it happens in corectrl as well), then it's likely a GPU firmware issue.

[StarTroop]

I have the same issue with my Dell 6600 xt. In corectl the fan stop does work. Only in LACT does the fan not totally spin down (minimum around 31%, 1010 rpm for me). Checking /sys/class/drm/card1/device/hwmon/hwmon1/fan1_input and /sys/class/drm/card1/device/hwmon/hwmon1/fan1_target whenever I manually set fan speed to anything under 31% always shows a number around 1010, never below.
I can hear the fan spinning so I know it's not just a reporting bug.

[Kenzyss]

Yes, it's probably a hardware limitation. When I set the fans to static (with pwm=0), then
cat /sys/class/drm/card1/device/hwmon/hwmon1/pwm1
cat /sys/class/drm/card1/device/hwmon/hwmon1/pwm1_min
are equal to 0 (as in auto mode), but

cat /sys/class/drm/card1/device/hwmon/hwmon1/fan1_input
520
cat /sys/class/drm/card1/device/hwmon/hwmon1/fan1_target
516
cat /sys/class/drm/card1/device/hwmon/hwmon1/fan1_min
0

That is, fan1_min = 0, but for some reason the fan speed is equal to fan1_target(~520rpm)
In auto mode fan1_target = 0

Maybe there is some way to solve this problem?
AMD GPU RX 6800xt (Reference)