#!/bin/bash

# This script limits the threshholds of the superloud supermicro fans to more 
# manageable values, if used as is (instead of swapping fans for e.g. noctua fans).
# Put this in e.G. /etc/init.d/ , because values are reverted on powerloss.

# set limits in 64 steps from 00-FF (convert to hex!):
# 0x00 ==   0% / minimal
# ...
# 0x16 ==  25%
# 0x24 ==  37.5%
# 0x32 ==  50%
# ... 
# 0x64 == 100% / fullspeed

LIMIT="0x16"

# number of fans installable on given mainboard (check with e.G. `ipmitool sdr | grep -i rpm`)
FANCOUNT="8"

# fan critical limits

LNR="300" # Lower Non-Recoverable
LC="500"  # Lower Critical
LNC="700" # Lower Non-Critical

UNC="10000" # Upper Non-Critical
UC="10500"  # Upper Critical
UNR="11000" # Upper Non-Recoverable

# check availability of ipmitool
if
        which ipmitool >/dev/null
then 
        echo "ipmitool available. Continue."
else
        echo "ipmitool not installed. Aborting."
        exit 1
fi

# limit upper and lower values for fans 1-8 to non-unrealistic values
for fan in $(seq 1 $FANCOUNT); do
    /usr/bin/ipmitool sensor thresh FAN$fan upper $UNC $UC $UNR
    /usr/bin/ipmitool sensor thresh FAN$fan lower $LNR $LC $LNC    
done

echo "set fan mode to full (needed for static control) and let things settle"
/usr/bin/ipmitool raw 0x30 0x45 0x01 0x01; sleep 10

echo "set fans in "system" zone to 25% and let things settle"
/usr/bin/ipmitool raw 0x30 0x70 0x66 0x01 0x00 $LIMIT; sleep 5

echo "set fans in "peripheral" zone to 25% and let things settle"
/usr/bin/ipmitool raw 0x30 0x70 0x66 0x01 0x01 $LIMIT; sleep 5

echo "all done"