Kernel Bug Tracker – Bug 14853
therm_adt746x might have inverted fan speed logic
Last modified: 2013-04-09 06:23:26 UTC
I just recently upgraded to .32 from .31 on my Powerbook 5,2. The fans worked properly, as in, when it got warm it turned the fans on, when it got cold, it turns the fans off.
However, .32 now turns the fans on soon as therm_adt746x is loaded, the fans crank up to full throttle, even though the temperatures are at least 10 degrees below sensor1_limit and sensor2_limit in /sys/devices/temperatures.
Trying to manually set the limits with echo -n foo > sensorn_limit to 20 degrees cooler (as opposed to warmer) causes the fans to shut off, but after several minutes the box halts and powers off (probably triggering some safety limit to prevent hardware damage).
I'm not sure how sensorn_fan_speed works, but the fans are at the their fastest at 0, and medium speed at 91, and stopped altogether at 255.
please attach the acpidump output.
I suspect the fan is not controlled via acpi.
Hmm, apparently acpidump works only on x86. This is a Powerbook and has a PowerPC processor.
I'll reassign this to powerpc.
Does that fix it ?
Ben, that patch does seem to fix it correctly.