Ubuntu – How to 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'.