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Manual Pages  — ACPI_IBM


acpi_ibm – ACPI extras driver for IBM laptops



To compile this driver into the kernel, place the following line in your kernel configuration file: device acpi_ibm

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):



The acpi_ibm driver provides support for hotkeys and other components of IBM laptops. The main purpose of this driver is to provide an interface, accessible via sysctl(8) and devd(8), through which applications can determine the status of various laptop components.

While the sysctl(8) interface is enabled automatically after loading the driver, the devd(8) interface has to be enabled explicitly, as it may alter the default action of certain keys. This is done by setting the events sysctl as described below. Specifying which keys should generate events is done by setting a bitmask, whereas each bit represents one key or key combination. This bitmask, accessible via the eventmask sysctl, is set to availmask by default, a value representing all possible keypress events on the specific ThinkPad model.

devd(8) Events

Hotkey events received by devd(8) provide the following information:

system "ACPI"
type The source of the event in the ACPI namespace. The value depends on the model.
notify Event code (see below).

Depending on the ThinkPad model, event codes may vary. On a ThinkPad T41p these are as follows:

0x01 Fn + F1
0x02 Fn + F2
0x03 Fn + F3 (LCD backlight)
0x04 Fn + F4 (Suspend to RAM)
0x05 Fn + F5 (Bluetooth)
0x06 Fn + F6
0x07 Fn + F7 (Screen expand)
0x08 Fn + F8
0x09 Fn + F9
0x0a Fn + F10
0x0b Fn + F11
0x0c Fn + F12 (Suspend to disk)
0x0d Fn + Backspace
0x0e Fn + Insert
0x0f Fn + Delete
0x10 Fn + Home (Brightness up)
0x11 Fn + End (Brightness down)
0x12 Fn + PageUp (ThinkLight)
0x13 Fn + PageDown
0x14 Fn + Space (Zoom)
0x15 Volume Up
0x16 Volume Down
0x17 Mute
0x18 Access IBM Button

led(4) Interface

The acpi_ibm driver provides a led(4) interface for the ThinkLight. The ThinkLight can be made to blink by writing ASCII strings to the /dev/led/thinklight device.


The following sysctls are currently implemented:
  (read-only) Bitmask of ACPI events before the acpi_ibm driver was loaded.
  (read-only) Bitmask of all supported ACPI events.
  Enable ACPI events and set the eventmask to availmask. Without the acpi_ibm driver being loaded, only the Fn+F4 button generates an ACPI event.
  Sets the ACPI events which are reported to devd(8). Fn+F3, Fn+F4 and Fn+F12 always generate ACPI events, regardless which value eventmask has. Depending on the ThinkPad model, the meaning of different bits in the eventmask may vary. On a ThinkPad T41p this is a bitwise OR of the following:

1 Fn + F1
2 Fn + F2
4 Fn + F3 (LCD backlight)
8 Fn + F4 (Suspend to RAM)
16 Fn + F5 (Bluetooth)
32 Fn + F6
64 Fn + F7 (Screen expand)
128 Fn + F8
256 Fn + F9
512 Fn + F10
1024 Fn + F11
2048 Fn + F12 (Suspend to disk)
4096 Fn + Backspace
8192 Fn + Insert
16384 Fn + Delete
32768 Fn + Home (Brightness up)
65536 Fn + End (Brightness down)
131072 Fn + PageUp (ThinkLight)
262144 Fn + PageDown
524288 Fn + Space (Zoom)
1048576 Volume Up
2097152 Volume Down
4194304 Mute
8388608 Access IBM Button
  (read-only) Status of several buttons. Every time a button is pressed, the respecting bit is toggled. It is a bitwise OR of the following:

1 Home Button
2 Search Button
4 Mail Button
8 Access IBM Button
16 Zoom
32 Wireless LAN Button
64 Video Button
128 Hibernate Button
256 ThinkLight Button
512 Screen Expand
1024 Brightness Up/Down Button
2048 Volume Up/Down/Mute Button
  Current brightness level of the display.
  Speaker volume.
  Indicates, whether the speakers are muted or not.
  Indicates, whether the ThinkLight keyboard light is activated or not.
  Toggle Bluetooth chip activity.
  (read-only) Indicates whether the WLAN chip is active or not.
  Indicates whether the fan is in automatic (1) or manual (0) mode. Default is automatic mode. This sysctl should be used with extreme precaution, since disabling automatic fan control might overheat the ThinkPad and lead to permanent damage if the fan_level is not set accordingly.
  Indicates at what speed the fan should run when being in manual mode. Values are ranging from 0 (off) to 7 (max). The resulting speed differs from model to model. On a T41p this is as follows:

0 off
1, 2 ~3000 RPM
3, 4, 5 ~3600 RPM
6, 7 ~4300 RPM
  (read-only) Fan speed in rounds per minute. A few older ThinkPads report the fan speed in levels ranging from 0 (off) to 7 (max).
  (read-only) Shows the readings of up to eight different temperature sensors. Most ThinkPads include six or more temperature sensors but only expose the CPU temperature through acpi_thermal(4). Some ThinkPads have the below sensor layout which might vary depending on the specific model:

  1. CPU
  2. Mini PCI Module
  3. HDD
  4. GPU
  5. Built-in battery
  6. UltraBay battery
  7. Built-in battery
  8. UltraBay battery
  devd(8) events handled by acpi_ibm when events is set to 1. Events are specified as a whitespace-separated list of event code in hexadecimal or decimal form. Note that the event maybe handled twice (e.g., Brightness up/down) if ACPI BIOS already handled the event.

Defaults for these sysctls can be set in sysctl.conf(5).


  ThinkLight led(4) device node


The following can be added to devd.conf(5) in order to pass button events to a /usr/local/sbin/acpi_oem_exec.sh script:
notify 10 {
        match "system"          "ACPI";
        match "subsystem"       "IBM";
        action "/usr/local/sbin/acpi_oem_exec.sh $notify ibm";

A possible /usr/local/sbin/acpi_oem_exec.sh script might look like:

if [ "$1" = "" -o "$2" = "" ]
        echo "usage: $0 notify oem_name"
        exit 1
NOTIFY=`echo $1`

case ${NOTIFY} in 0x05) LEVEL=`sysctl -n dev.acpi_${OEM}.0.bluetooth` if [ "$LEVEL" = "1" ] then sysctl dev.acpi_${OEM}.0.bluetooth=0 MESSAGE="bluetooth disabled" else sysctl dev.acpi_${OEM}.0.bluetooth=1 MESSAGE="bluetooth enabled" fi ;; 0x10|0x11) LEVEL=`sysctl -n dev.acpi_${OEM}.0.lcd_brightness` PERCENT=`${ECHO} "${BC_PRECOMMANDS} ; \ ${LEVEL} / ${MAX_LCD_BRIGHTNESS} * 100" |\ ${CALC} | ${CUT} -d . -f 1` MESSAGE="brightness level ${PERCENT}%" ;; 0x12) LEVEL=`sysctl -n dev.acpi_${OEM}.0.thinklight` if [ "$LEVEL" = "1" ] then MESSAGE="thinklight enabled" else MESSAGE="thinklight disabled" fi ;; 0x15|0x16) LEVEL=`sysctl -n dev.acpi_${OEM}.0.volume` PERCENT=`${ECHO} "${BC_PRECOMMANDS} ; \ ${LEVEL} / ${MAX_VOLUME} * 100" | \ ${CALC} | ${CUT} -d . -f 1` MESSAGE="volume level ${PERCENT}%" ;; 0x17) LEVEL=`sysctl -n dev.acpi_${OEM}.0.mute` if [ "$LEVEL" = "1" ] then MESSAGE="volume muted" else MESSAGE="volume unmuted" fi ;; *) ;; esac ${LOGGER} ${MESSAGE} if [ -p ${DISPLAY_PIPE} ] then ${ECHO} ${MESSAGE} >> ${DISPLAY_PIPE} & fi exit 0

The following example specify that event code 0x04 (Suspend to RAM), 0x10 (Brightness up) and 0x11 (Brightness down) are handled by acpi_ibm.

sysctl dev.acpi_ibm.0.handlerevents='0x04 0x10 0x11'

in sysctl.conf(5):

dev.acpi_ibm.0.handlerevents=0x04\ 0x10\ 0x11


acpi(4), led(4), sysctl.conf(5), devd(8), sysctl(8)


The acpi_ibm device driver first appeared in FreeBSD 6.0 .


The acpi_ibm driver was written by Takanori Watanabe <Mt takawata@FreeBSD.org> and later mostly rewritten by Markus Brueffer <Mt markus@FreeBSD.org>. This manual page was written by Christian Brueffer <Mt brueffer@FreeBSD.org> and Markus Brueffer <Mt markus@FreeBSD.org>.

ACPI_IBM (4) June 19, 2015

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