Yesterday I've installed macppc -current on a G5. Since OF_getprop() for the 'unmanage-value' parameter fails on it, smu(4) sets the fan speed to 'max-value' instead, which is 3200RPM in my case. This makes the G5 sound louder than my vacuum cleaner.
First I thought 'unmanage-value' is a typo and it should be 'unmanaged-value' like in the FreeBSD driver, but unfortunately it still did fail. I saw that the FreeBSD driver doesn't set the fan speed at all initially in their driver. When I do the same on the G5, the fan speed goes to a decent of ~1000RPM: hw.sensors.smu0.fan0=999 RPM (Rear Fan 0) hw.sensors.smu0.fan1=999 RPM (Rear fan 1) hw.sensors.smu0.fan2=999 RPM (Front Fan) I don't know what the right way is to fix this, but skipping to set the fan speed when the 'unmanage-value' isn't available seems to work fine in this case. Index: sys/arch/macppc/dev/smu.c =================================================================== RCS file: /cvs/src/sys/arch/macppc/dev/smu.c,v retrieving revision 1.27 diff -u -p -u -p -r1.27 smu.c --- sys/arch/macppc/dev/smu.c 4 Jun 2015 18:01:44 -0000 1.27 +++ sys/arch/macppc/dev/smu.c 15 Apr 2016 18:17:12 -0000 @@ -281,15 +281,17 @@ smu_attach(struct device *parent, struct val = 0xffff; fan->max_rpm = val; if (OF_getprop(node, "unmanage-value", &val, sizeof val) <= 0) - val = fan->max_rpm; + val = 0; fan->unmanaged_rpm = val; if (OF_getprop(node, "location", loc, sizeof loc) <= 0) strlcpy(loc, "Unknown", sizeof loc); strlcpy(fan->sensor.desc, loc, sizeof sensor->sensor.desc); - /* Start running fans at their "unmanaged" speed. */ - smu_fan_set_rpm(sc, fan, fan->unmanaged_rpm); + if (fan->unmanaged_rpm) { + /* Start running fans at their "unmanaged" speed. */ + smu_fan_set_rpm(sc, fan, fan->unmanaged_rpm); + } #ifndef SMALL_KERNEL sensor_attach(&sc->sc_sensordev, &fan->sensor);