Apple System Management Control (SMC) utility
Forked from original smc_util repository, with a couple of other, slightly modified, SMC-related tools:
- powermetrics.d from https://gist.github.com/beltex/acbbeef815a7be938abf
- SmcDumpKey.c from https://www.contrib.andrew.cmu.edu/~somlo/OSXKVM/
Chances are you're here because of my blog post or SO question, and want to use this to turn an old iMac running Linux into a display.
Note: This was tested on a mid-2010 27" iMac running Yosemite and Ubuntu 16.04. Any other model/OS combo might behave differently.
Note: I don't have the iMac I used for this anymore, so I can't test anything, sorry. That being said, the steps to use this are (on Ubuntu and derivatives):
sudo apt-get install build-essential
git clone https://github.com/floe/smc_util.git
cd smc_util
gcc -O2 -o SmcDumpKey SmcDumpKey.c -Wall
sudo rmmod applesmc # remove the SMC kernel driver to avoid conflicts
sudo ./tdm_on.sh # enable target display mode
sudo ./tdm_off.sh # disable target display mode
IMPORTANT: when you run tdm_on.sh and it works on your iMac, then the display will switch over to the DP input and you won't have the console anymore. Make sure you have a remote shell open first, or maybe a keyboard hotkey set up, so you can also run tdm_off.sh again to switch back to the internal iMac graphics.