Talk:Fan control scripts

Wyrfel, are you sure the recent (19:54, 27 Oct 2005) cosmetic change was a good idea? The extensive chunks of code make it hard to grok the structure of the article in the absense of separator lines (which "===" doesn't have). --Thinker 22:10, 27 Oct 2005 (CEST)

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We can discuss this. From my point of view, the chunks of code distinguish themselves from each other quite well, because they are each in one code block.

I do not like the = section level - and so far we avoided them on all pages - because

• it generates H1 headings, which is the same as the page heading,
• having more than one level with the hbars is confusing/less readable, because they are not very well distinguishable. This way i.e. the "Other" section looked like a separate empty secion.

I think the way it's now, the separator lines make it possible to easily distinguish the different main sections, while when you have both levels with separator lines, an additional task of distinguishing H1 and H2 separators is necessary.

However, i see your point as well and would like to hear more opinions/arguments.

Wyrfel 22:31, 27 Oct 2005 (CEST)

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bash script with fine control over fan speed (for unpatched kernels)

Here's an alternative variable speed control script that doesn't need the patch for controlling fan speed. It requires only ibm-acpi 0.11 or higher (e.g., as found in kernel 2.6.14 and higher) with the experimental=1 module parameter.

Alas, at the moment I don't have a suitable to test it on. Can someone give it a try and report?

#!/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.
#
# 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
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 > $IBM_ACPI/fan; exit 0" EXIT HUP INT ABRT QUIT SEGV TERM


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

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

setlevel() { # set fan speed level
    $DRY_RUN || echo 0x2F $1 > $IBM_ACPI/ecdump
}

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"
    setlevel $NEWLEVEL

    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
		setlevel 0x40 # disengaged
		sleep 0.5
	    fi
	else
	    SETTLE=6
	fi
    fi

    IDX=$NEWIDX
done

--Thinker 15:07, 3 Nov 2005 (CET)

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IBM_ACPI was defined twice by accident I guess (changed above), but otherwise it seems to work fine, went from level 0 (cold machine) to 7 while compiling the kernel and now back to level 2 now at about 53 degrees Celsius.

--spiney 10:31, 5 Nov 2005 (CET)