Slackware64 iMac 2007 Redux

A year ago, I refurbished a vintage 2007 iMac: 1TB SSD and new(-ish) power
supply and it has been working pretty good for the most part.

Installing Slackware64-15.0 on an iMac 2007
https://www.linuxgalaxy.org/kingbeowulf/installing-slackware64-150-on-an-imac-2007/

Two issue still remain: Bluetooth (BT) and a tendency for the power supply
over heat.  I still haven't found a solution yet to the BT driver; this will
wait for the next stackware stable release "when it's ready; real soon now."

The mid 2007 iMac did have a tendency to overheat.  Having poked around
inside, there just isn't enough air flow to cool the power supply which can
run extra hot under load.  We can adjust the fan speed manualy as root, once
you figure out which fan cools both the CPU and the power supply.

For example:

# echo 1 > /sys/class/hwmon/hwmon3/device/fan3_manual
# echo 1500 > /sys/class/hwmon/hwmon3/device/fan3_output
# echo 2000 > /sys/class/hwmon/hwmon3/device/fan3_output

I was about to cobble somthing together when I stumbled across a great litte
daemon to do it all for me. So, why reinvent the wheel?

mbpfan: Adjust fan speed using the applesmc module

mbpfan is a great, simple program to tweak the fan curves when running Linux
on a macbook or an iMac.

https://github.com/linux-on-mac/mbpfan

For Slackware (there are other distros?), you can build a nice installable
package,

http://slackbuilds.org/repository/15.0/system/mbpfan/?search=mbpfan

To run mbpfan at system boot, add it to /etc/rc.d/rc.local

---------8<-------------
# mbpfan daemon to keep power supply from over heating (iMac 2007)
# see /etc/mbpfan.conf
/usr/sbin/mbpfan
--------->8-------------

Then edit /etc/mbpfan.conf as needed:

---------8<-------------
min_fan3_speed = 1500
max_fan3_speed = 3300

# temperature units in celcius
low_temp = 50          # if temperature is below this, fans will run at minimum speed
high_temp = 60         # if temperature is above this, fan speed will gradually increase
max_temp = 75          # if temperature is above this, fans will run at maximum speed
polling_interval = 1   # default is 1 seconds
---------8<-------------

You may need to experiment a bit for your particular Mac.

Have fun!