ThinkGNU: Put script in

 block, so it can be copy-pasted

2025-04-11T07:24:42Z

Put script in <pre> block, so it can be copy-pasted

Thinker: moved from ACPI fan control script

2006-07-26T21:08:21Z

moved from ACPI fan control script

New page

#!/bin/bash

# This script dynamically controls fan speed on some ThinkPad models
# according to user-defined temperature thresholds. It implements its
# own decision algorithm, overriding the ThinkPad embedded
# controller. It also implements a workaround for the fan noise pulse
# experienced every few seconds on some ThinkPads.
#
# The script requires the ibm_acpi patch at
# http://thinkwiki.org/wiki/Patch_for_controlling_fan_speed
#
# WARNING: This script relies on undocumented hardware features and
# overrides nominal hardware behavior. It may thus cause arbitrary
# damage to your laptop or data. Watch your temperatures!
#
# This file is placed in the public domain and may be freely distributed.

LEVELS=( 0 2 4 7) # Fan speed levels
UP_TEMPS=( 52 60 68 ) # Speed increase trip points
DOWN_TEMPS=( 48 56 64 ) # Speed decrease trip points

ANTIPULSE=( 0 1 0 0) # Prevent fan pulsing noise at this level
# (this also prevents fan speed updates)

IBM_ACPI=/proc/acpi/ibm
FAN=$IBM_ACPI/fan
INTERVAL=3
VERBOSE=true
DRY_RUN=false

[[ "$1" == "-t" ]] && { DRY_RUN=true; echo "$0: Dry run, will not change fan state."; }

# Enable the fan in default mode if anything goes wrong:
set -e -E -u
$DRY_RUN || trap "echo enable > $FAN; exit 0" EXIT HUP INT ABRT QUIT SEGV TERM

thermometer() { # output list of temperatures
read X Y < $IBM_ACPI/thermal
[[ "$X" == "temperatures:" ]] || {
echo "$0: Bad temperatures: $X $Y" >&2
exit 1
}
echo "$Y";
}

speedometer() { # output fan speed
cat $FAN | sed '/^speed/!d; s/speed:[ \t]*//'
}

IDX=0
MAX_IDX=$(( ${#LEVELS[@]} - 1 ))
SETTLE=0

while true; do
TEMPS=`thermometer`
$VERBOSE && SPEED=`speedometer`

# Calculate new level
NEWIDX=$IDX
DOWN=$(( IDX > 0 ))
for TEMP in $TEMPS; do
# Increase speed as much as needed
while [[ $NEWIDX -lt $MAX_IDX ]] &&
[[ $TEMP -ge ${UP_TEMPS[$NEWIDX]} ]]; do
(( NEWIDX ++ ))
DOWN=0
done
# Allow decrease (by one index)?
if [[ $DOWN == 1 ]] &&
[[ $TEMP -gt ${DOWN_TEMPS[$(( IDX - 1 ))]} ]]; then
DOWN=0
fi
done
if [[ $DOWN == 1 ]]; then
NEWIDX=$(( IDX - 1 ))
fi

# Transition
OLDLEVEL=${LEVELS[$IDX]}
NEWLEVEL=${LEVELS[$NEWIDX]}
$VERBOSE && echo "tpfan: Temps: $TEMPS Fan: $SPEED Level: $OLDLEVEL->$NEWLEVEL"
$DRY_RUN || echo level $NEWLEVEL > $FAN

sleep $INTERVAL

# If needed, apply anti-pulsing hack after a settle-down period:
if [[ ${ANTIPULSE[${NEWIDX}]} == 1 ]]; then
if [[ $NEWLEVEL == $OLDLEVEL ]]; then
if [[ $SETTLE -ge 0 ]]; then
(( SETTLE -= INTERVAL ))
else
$DRY_RUN || echo level disengaged >> $FAN
sleep 0.5
fi
else
SETTLE=6
fi
fi

IDX=$NEWIDX
done

Code/tp-fancontrol-basic - Revision history

ThinkGNU: Put script in
block, so it can be copy-pasted

Thinker: moved from ACPI fan control script

@@ Line 1: / Line 1: @@
 #!/bin/bash
@@ Line 101: / Line 102: @@
      IDX=$NEWIDX
 done