After a few tests i can say that at least in my system it’s not working. Setting a value between 0 and 4 in /sys/.../panel_power_savings changes nothing in the panel behavior.
Setting an abmlevel via kernel option still works as intended.
Should setting a value in /sys/.../panel_power_savings appear in /sys/module/amdgpu/parameters/abmlevel?
What am I missing?
Update: Further investigation shows that setting an abmlevel via kernel option appears in /sys/…/panel_power_savings. The other way around it is not working unfortunately.