Using Ubuntu 18 (Linux 4.15.0-72-generic) on a mid 2010 iMac 27", I found that the CPU fan always runs on the slow 940rpm regardless of the CPU temperature. Hardware support is great for that machine, only fan and display back light control support seem to be missing.
I wrote own code to control the fans, but I have the feeling that I am just missing something here. Is there anything more "standard" or "straight-forward", like just configuring target temperature and fans?