[ltp] Fan-problem-solution-proposal

[Florian Dorpmueller]

For those who like to do something with their fan, I have writen a little 
script. You can use it as deamon or start it as local user (therefore you 
need to change the rights of /proc/acpi/ibm/fan).

On my R51 this script reduces the fan usage remarkable. Under normal 
circumstances (20 degrees centigrade) I notice about 8 minutes fanless 
working and afterwards around 10 minutes cooling.

Try and enjoy,
Flori

#!/bin/sh
#
# fan control-script
#
# based upon ibm-acpi 0.11
#
# eliminates anoying "fan always on" in battery mode
# works with hysteresis (DELTA) so that always-turn-on/turn-off is avoided
# fan acivates at MAXTEMP and cools down CPU, GPU etc. to MAXTEMP-DELTA than 
the fan is turned off
# furthermore detects if AC is on and gives back fan control to default 
behaviour than
#
# one can change MAXTEMP and DELTA to individual values
# but take care of your THINKPAD don`t melt it!
#
# have fun!
# Flori 05.05.05

MAXTEMP=50
DELTA=4

SWITCHTEMP=$MAXTEMP

while [ 1 ];
do
   for ac in `sed s/state:// < /proc/acpi/ac_adapter/AC/state`
     do
      if [ "$ac" = "off-line" ]; then
          fan=no
          for temp in `sed s/temperatures:// < /proc/acpi/ibm/thermal`
            do
              test $temp -gt $SWITCHTEMP && fan=yes
            done

          if [ "$fan" = "yes" ]; then
            command='enable'
            SWITCHTEMP=`expr $MAXTEMP - $DELTA`
          else
            SWITCHTEMP=$MAXTEMP
            command='disable'
          fi

        else # ac-adapter on -> set fan control to standard behaviour
          command='enable'
        fi

        echo $command > /proc/acpi/ibm/fan
        sleep 15
      done
   done