acpid
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acpid2 is a flexible and extensible daemon for delivering ACPI events. When an event occurs, executes programs to handle the event. These events are triggered by certain actions, such as:
- Pressing special keys, including the Power/Sleep/Suspend button
- Closing a notebook lid
- (Un)Plugging an AC power adapter from a notebook
- (Un)Plugging phone jack etc.
Contents
Installation
Install the acpid package, available in the official repositories.
To have acpid started on boot, enable acpid.service
.
Configuration
acpid comes with a number of predefined actions for triggered events, such as what should happen when you press the Power button on your machine. By default, these actions are defined in /etc/acpi/handler.sh
, which is executed after any ACPI events are detected (as determined by /etc/acpi/events/anything
).
The following is a brief example of one such action. In this case, when the Sleep button is pressed, acpid runs the command echo -n mem >/sys/power/state
which should place the computer into a sleep (suspend) state:
button/sleep) case "$2" in SLPB) echo -n mem >/sys/power/state ;; *) logger "ACPI action undefined: $2" ;; esac ;;
Unfortunately, not every computer labels ACPI events in the same way. For example, the Sleep button may be identified on one machine as SLPB and on another as SBTN.
To determine how your buttons or Fn
shortcuts are recognized, run the following command:
# journalctl -f
Now press the Power button and/or Sleep button (e.g. Fn+Esc
) on your machine. The result should look something this:
logger: ACPI action undefined: PBTN logger: ACPI action undefined: SBTN
If that does not work, run:
# acpi_listen
or with openbsd-netcat:
$ netcat -U /var/run/acpid.socket
Then press the power button and you will see something like this:
power/button PBTN 00000000 00000b31
The output of acpi_listen
is sent to /etc/acpi/handler.sh
as $1, $2 , $3 & $4 parameters.
Example:
$1 power/button $2 PBTN $3 00000000 $4 00000b31
As you might have noticed, the Sleep button in the sample output is actually recognized as SBTN, rather than the SLPB label specified in the default /etc/acpi/handler.sh
. In order for Sleep function to work properly on this machine, we would need to replace SLPB) with SBTN).
Using this information as a base, you can easily customize the /etc/acpi/handler.sh
file to execute a variety of commands depending on which event is triggered. See the Tips & Tricks section below for other commonly used commands.
Alternative configuration
By default, all ACPI events are passed through the /etc/acpi/handler.sh
script. This is due to the ruleset outlined in /etc/acpi/events/anything
:
# Pass all events to our one handler script event=.* action=/etc/acpi/handler.sh %e
While this works just fine as it is, some users may prefer to define event rules and actions in their own self-contained scripts. The following is an example of how to use an individual event file and corresponding action script:
As root, create the following file:
/etc/acpi/events/sleep-button
event=button sleep.* action=/etc/acpi/actions/sleep-button.sh %e
Now create the following file:
/etc/acpi/actions/sleep-button.sh
#!/bin/sh case "$3" in SLPB) echo -n mem >/sys/power/state ;; *) logger "ACPI action undefined: $3" ;; esac
Finally, make the script executable:
# chmod +x /etc/acpi/actions/sleep-button.sh
Using this method, it is easy to create any number of individual event/action scripts.
Tips and tricks
Example events
The following are examples of events that can be used in the /etc/acpi/handler.sh
script. These examples should be modified so that they apply your specific environment e.g. changing the event variable names interpreted by acpi_listen
.
To lock the screen with xscreensaver
when closing the laptop lid:
button/lid) case $3 in close) # The lock command need to be run as the user who owns the xscreensaver process and not as root. # See: man xscreensaver-command. $xs will have the value of the user owning the process, if any. xs=$(ps -C xscreensaver -o user=) if test $xs; then su $xs -c "xscreensaver-command -lock"; fi ;;
To suspend the system and lock the screen using slimlock
when the lid is closed:
button/lid) case $3 in close) #echo "LID switched!">/dev/tty5 /usr/bin/pm-suspend & DISPLAY=:0.0 su -c - username /usr/bin/slimlock ;;
To lock the screen using gnome-screensaver-command
when the lid is closed:
button/lid) case "$3" in close) export DISPLAY=:0.0 xs=$(ps -C gnome-screensaver -o user=) if test $xs; then su $xs -c "gnome-screensaver-command -l"; fi ;;
To set the laptop screen brightness when plugged in power or not (the numbers might need to be adjusted, see /sys/class/backlight/acpi_video0/max_brightness
):
ac_adapter) case "$2" in AC*|AD*) case "$4" in 00000000) echo -n 50 > /sys/class/backlight/acpi_video0/brightness ;; 00000001) echo -n 100 > /sys/class/backlight/acpi_video0/brightness ;; esac
Enabling volume control
Find out the acpi identity of the volume buttons (see above) and susbtitute it for the acpi events in the files below.
/etc/acpi/events/vol-d
event=button/volumedown action=amixer set Master 5-
/etc/acpi/events/vol-m
event=button/mute action=amixer set Master toggle
/etc/acpi/events/vol-u
event=button/volumeup action=amixer set Master 5+
Enabling backlight control
Similar to volume control, acpid also enables you to control screen backlight. To achieve this you write some handler, like this:
/etc/acpi/handlers/bl
#!/bin/sh bl_dev=/sys/class/backlight/acpi_video0 step=1 case $1 in -) echo $(($(< $bl_dev/brightness) - $step)) >$bl_dev/brightness;; +) echo $(($(< $bl_dev/brightness) + $step)) >$bl_dev/brightness;; esac
and again, connect keys to ACPI events:
/etc/acpi/events/bl_d
event=video/brightnessdown action=/etc/acpi/handlers/bl -
/etc/acpi/events/bl_u
event=video/brightnessup action=/etc/acpi/handlers/bl +
Enabling Wi-Fi toggle
You can also create a simple wireless-power switch by pressing the WLAN button. Example of event:
/etc/acpi/events/wlan
event=button/wlan action=/etc/acpi/handlers/wlan
and its handler:
/etc/acpi/handlers/wlan
#!/bin/sh rf=/sys/class/rfkill/rfkill0 case $(< $rf/state) in 0) echo 1 >$rf/state;; 1) echo 0 >$rf/state;; esac
Laptop monitor power off
Adapted from the Gentoo Wiki comes this little gem. Add this to the button/lid section of /etc/acpi/handler.sh
. This will turn off the LCD back-light when the lid is closed, and restart when the lid is opened.
case $(awk '{print $2}' /proc/acpi/button/lid/LID0/state) in closed) XAUTHORITY=$(ps -C xinit -f --no-header | sed -n 's/.*-auth //; s/ -[^ ].*//; p') xset -display :0 dpms force off ;; open) XAUTHORITY=$(ps -C xinit -f --no-header | sed -n 's/.*-auth //; s/ -[^ ].*//; p') xset -display :0 dpms force on ;; esac
If you would like to increase/decrease brightness or anything dependent on X, you should specify the X display as well as the MIT magic cookie file (via XAUTHORITY). The last is a security credential providing read and write access to the X server, display, and any input devices.
Here is another script not using XAUTHORITY but sudo:
case $(awk '{print $2}' /proc/acpi/button/lid/LID0/state) in closed) sudo -u $(ps -o ruser= -C xinit) xset -display :0 dpms force off ;; open) sudo -u $(ps -o ruser= -C xinit) xset -display :0 dpms force on ;; esac
With certain combinations of Xorg and stubborn hardware, xset dpms force off
only blanks the display leaving the backlight turned on. This can be fixed using vbetool from the official repositories. Change the LCD section to:
case $(awk '{print $2}' /proc/acpi/button/lid/LID0/state) in closed) vbetool dpms off ;; open) vbetool dpms on ;; esac
If the monitor appears to shut off only briefly before being re-powered, very possibly the power management shipped with xscreensaver conflicts with any manual dpms settings.
Getting user name of the current display
You can use the function getuser
to discover the user of the current display:
getuser() { # Only gets the first session user=$(w -h -s | awk '/( :[[:digit:]]*)/ { print $1 }') export DISPLAY=$(w -h -s | grep -o " :[[:digit:]]" | awk '{ print $1 }') if [[ $user ]]; then export XAUTHORITY="/home/$user/.Xauthority" sudo -u "$user" "$@" else return 1 fi }
An alternative is to use loginctl
to obtain the required information, e.g. using xuserrun.
ACPI hotkey
You can either directly edit /etc/acpi/handler.sh
, to react to the ACPI events, or you can point it to another shell script (i.e. /etc/acpi/hotkeys.sh
)
Under the section
case "$1" in
Add the following lines:
hkey) case "$4" in 00000b31) echo "PreviousButton pressed!" exailectl p ;; 00000b32) echo "NextButton pressed!" exailectl n ;; 00000b33) echo "Play/PauseButton pressed!" exailectl pp echo "executed.." ;; 00000b30) echo "StopButton pressed!" exailectl s ;; *) echo "Hotkey Else: $4" ;; esac ;;
The '00000b31' etc. values are the response received from acpi_listen.
Also, the exailectl script is a brief shell script I created for controlling Exaile music player. As the ACPID is run from root, you will need to use
$ sudo -u username exaile
for example, otherwise it will not detect your user-level program and recreate another.
See also
- http://acpid.sourceforge.net/ - acpid homepage
- http://www.gentoo-wiki.info/ACPI/Configuration - Gentoo wiki