How do I disable the touchpad when the lid is twisted or closed?

To check whether the device is in tablet mode or not we could read the value (0 or 1) of:

/sys/devices/platform/thinkpad_acpi/hotkey_tablet_mode

This value is switched by specific events. We can catch these events and could bind scripts to them by using acpid - Advanced Configuration and Power Interface event daemon.

1. Catch the events. Execute acpi_listen or netcat -U /var/run/acpid.socket, turn the lid in tablet mode, then turn it back. Here is an example output:

$ acpi_listen
video/tabletmode TBLT 0000008A 00000001
video/tabletmode TBLT 0000008A 00000000

Please note when the lid is close/open the result is different:

$ acpi_listen
button/lid LID close
button/lid LID open

2. Configure acpid to recognize the events triggered by the device mode change. Run the following lines into a terminal as (single) commands:

cat << EOF | sudo tee /etc/acpi/events/thinkpad-tablet-enabled
# /etc/acpi/events/thinkpad-tablet-enabled
# This is called when the lid is placed in tablet position on
# Lenovo ThinkPad X230 Tablet

event=video/tabletmode TBLT 0000008A 00000001
action=/etc/acpi/thinkpad-touchpad-twist-mode.sh 1
EOF

cat << EOF | sudo tee /etc/acpi/events/thinkpad-tablet-disabled
# /etc/acpi/events/thinkpad-tablet-disabled
# This is called when the lid is placed in normal position on
# Lenovo ThinkPad X230 Tablet

event=video/tabletmode TBLT 0000008A 00000000
action=/etc/acpi/thinkpad-touchpad-twist-mode.sh 0
EOF

The above commands will create the files:

• /etc/acpi/events/thinkpad-tablet-enabled
• /etc/acpi/events/thinkpad-tablet-disabled

Note: The scripts for lid open/close aren't provided here. But they are similar as the above.

3. Restart acpid so it can re-read the event filters, including the ones you just added:

sudo systemctl restart acpid.service

4. Create the script /etc/acpi/thinkpad-touchpad-in-twist-mode.sh that will disable 1 and enable 0 the touchpad (&& make it executable):

cat << EOF | sudo tee /etc/acpi/thinkpad-touchpad-twist-mode.sh && sudo chmod +x /etc/acpi/thinkpad-touchpad-twist-mode.sh
#!/bin/sh
LANG=C                                                                                                        # Ensure stable parsing
export DISPLAY="\$(w | awk 'NF > 7 && \$2 ~ /tty[0-9]+/ {print \$3; exit}' 2>/dev/null)"                      # Get and export the current user's \$DISPAY
export XAUTHORITY="/home/\$(w | awk 'NF > 7 && \$2 ~ /tty[0-9]+/ {print \$1; exit}' 2>/dev/null)/.Xauthority" # Get and export the currentuser's \$XAUTHORITY
ID="\$(xinput | grep -ioP 'touchpad.*id=\K[0-9]*')"                                                           # Find the TouchPad device ID

if   [ "\${1}" -eq 0 ]; then xinput enable "\$ID"   # Laptop mode or Lid is open
elif [ "\${1}" -eq 1 ]; then xinput disable "\$ID"  # Tablet mode or Lid is closed
fi
EOF

• The script will parse and export the environment variables $DISPAY and $XAUTHORITY of the current user's session, in order to allow root (who runs the acpid process) to access the user's X session, respectively xinput.
• Then the script will parse the $ID of the touchpad. And depending on the value of the input variable $1 it will enable or disable the touckpad.

Note: The backslashes before the dollar signs \$ are intended to escape the variable (command substitution) expansion within the cat command. So if you copy/paste the script (instead using of the cat approach) you should remove them manually.

References:

• ArchWiki: acpid - Advanced Configuration and Power Interface event daemon.
• Ask Ubuntu: How do I disable the touchpad while the lid is down?
• ThinkWiki: Installing Ubuntu 12.10 on Thinkpad Twist | Thinkpad-acpi | Wacom Tablet Stilus
• Ubuntu Forums: Touchpad ON/OFF | Why won't this acpi event work?
• About the parsing read: Programmatically find the current value of DISPLAY using w and awk and Remove particular words from lines using grep -P '\K'.

Using the answer of pa4080, I had to make this change for it to work in Ubuntu 18.04: hard code my user (tim) in the script and run the script in the context of my user.

File /etc/acpi/events/thinkpad-lid-event:

event=button/lid.*
action=su tim -c '/home/tim/scripts/lid.sh.post'

and lid.sh.post:

#! /bin/bash
# toggle touchpad enabled status when lid changes (lid closed,touchpad off)
# is run in user context
# 
# example rule /etc/acpi/events/thinkpad-lid-close
# event=button/lid.*
# action=su tim -c '/home/tim/scripts/lid.sh.post'  
#
# see https://askubuntu.com/questions/91534/disable-touchpad-while-the-lid-is-down
# and https://askubuntu.com/questions/980997/how-do-i-disable-the-touchpad-when-the-lid-is-twisted-or-closed/980999#980999
# this needs an event defined in /etc/acpi/events to call this script when lid status changes
# these variables need to be set to use xinput properly
user="tim"
export XAUTHORITY=$(ls -1 /home/$user/.Xauthority | head -n 1)
export DISPLAY=":$(ls -1 /tmp/.X11-unix/ | sed -e s/^X//g | head -n 1)"

export TouchPadID=$(xinput | grep 'TouchPad' | sed  -n "s/^.*id=\([[:digit:]]\+\).*$/\1/p")
grep -q closed /proc/acpi/button/lid/*/state
LidClosedResult=$?
xinput set-int-prop  $TouchPadID "Device Enabled" 8 $LidClosedResult
if [ $? -eq 0 ]; then
  echo "for user: $user xinput device $TouchPadID enabled status changed to $LidClosedResult because of LID ACPI event" | systemd-cat
else
  echo "failed to change xinput device $TouchPadID enabled status after LID ACPI event" | systemd-cat
fi

Made another variation acting on 'lid' and 'tabletmode' and just 2 rules catching the response from the ACPI events (use "%e" in the action, mind the quotes !):

#!/bin/bash
# toggle 'touchpad enabled status' off/on when lid changes (lid closed or tablet mode => touchpad off)
# 
# let it act on 2 rules in /etc/acpi/events/: lid-change and tabletmode-change:
# 
#     event=button/lid.*
#     action=/etc/acpi/touchpad-toggle.sh "%e"
#
#     event=video/tabletmode.*
#     action=/etc/acpi/touchpad-toggle.sh "%e"
#


# variables needed to use xinput properly
user1="$(who | cut -d ' ' -f1)"
export XAUTHORITY="$(ls -1 /home/$user1/.Xauthority | head -n 1)"
export DISPLAY=":$(ls -1 /tmp/.X11-unix/ | sed -e s/^X//g | head -n 1)"
export TPdID="$(xinput | grep -ioP 'touchpad.*id=\K[0-9]*')"

if [ "${@}" == "" ]; then
    echo "ACPI event didn't return trigger values." | systemd-cat
elif [ "$user1" == "" ]; then
    echo "ACPI event action didn't find current user." | systemd-cat
else
    false
    if   [ "${@}" == "button/lid LID open" ]; then xinput enable $TPdID
    elif [ "${@}" == "button/lid LID close" ]; then xinput disable $TPdID
    elif [ "${@}" == "video/tabletmode TBLT 0000008A 00000000" ]; then xinput enable $TPdID
    elif [ "${@}" == "video/tabletmode TBLT 0000008A 00000001" ]; then xinput disable $TPdID
    fi
    if [ $? -eq 0 ]; then
        echo "ACPI event: xinput device $TPdID status changed on ${@}." | systemd-cat
    else
        echo "ACPI event failed: xinput device $TPdID status NOT changed on ${@}." | systemd-cat
    fi
fi

Enjoy using the script ...

Edit: $USER doesn't always return a result when used by root ... So I replaced it using: user1="$(who | cut -d ' ' -f1)"