On Sun, Oct 12, 2014 at 9:12 AM, Felix Schulthess <fsch@xxxxxxxxxxx> wrote: > > You cannot control the fan speeds. They are managed by the onboard > > controller. You can choose one of several profiles in the bios but that > > is it. > > That explains a lot. Thank you for your help, I am going to do some > further research in this direction and read up on FreeIPMI. > > Still, if I can't control the fan speeds but they are instead controlled > by some onboard controller, then how could the installation on the > fancontrol and lm-sensors mess up the control loop so bad? This still > keeps me wondering. > You can't control the fan speeds because there is already another device on the motherboard that is tasked with the job of controlling them. As you found, you can poke the control chips, but that doesn't mean you can control the speeds predictably. Imagine two cooks in a kitchen trying to cook different meals with the same ingredients. They come and go in the kitchen unaware of the others meddling and confused why things are changing when they are away. You end up with no food. Only one cook in the kitchen. It's also possible that when you ran SDT it's default config was to change the BIOS/BMC setting on the fans speeds to full speed. As you found it was a permanent change to the setting, not some strange interaction between lm_sensors and sdt and the BMC. > Maybe, the sensors somehow blocked the CPU temperature readout. This > could have caused the superdoctor program to resort to some failsafe > behavior (i.e. spinning the fans up to max RPM). Just wondering. Also possible. Glad you got your system back under control In addition to the web interface, there is a BIOS screen where you can set the fan speed profile as well. Phil P. _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
