Krdytkyu

I have Lenovo ThinkPad X230 Tablet with Ubuntu 16.04. It has a convertible screen and when it is in tablet mode the touchpad is still active and make a mess.

I've created the following script and bound it to one of the built in buttons (by a custom shortcut):

#!/bin/bash -e



# Find the TouchPad device ID

ID="$(xinput | grep -ioP 'touchpad.*id=K[0-9]*')"                                  



if   [ "$(LANG=C xinput --list-props "$ID" | awk 'NR==2{print $4}')" == "0" ]; then 

        # If the device is disabled, then enable it and kill 'onboard' virtual keyboard

        xinput enable "$ID"; killall onboard; xrandr -o normal

elif [ "$(LANG=C xinput --list-props "$ID" | awk 'NR==2{print $4}')" == "1" ]; then

        # If the device is enabled, then disable it and run 'onboard' virtual keyboard

        xinput disable "$ID"; nohup onboard >/dev/null 2>&1 &

fi

The script works properly, but this is a fake solution and yesterday I spent few hours to learn how to do that in a proper way. So I decided to share this experience here.

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 in the script and run the script in the context of my user.

file: /etc/acpi/events/thinkpad-lid-close

event=button/lid LID close

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

file: /etc/acpi/events/thinkpad-lid-open

event=button/lid LID open

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

and lid.sh.post is

#! /bin/bash

# disable the touchpad if the lid is closed

# 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 two events defined in /etc/acpi/events which call this script

# user name is hardcoded which is an ugly hack





export XAUTHORITY=`ls -1 /home/tim/.Xauthority | head -n 1`

export DISPLAY=":`ls -1 /tmp/.X11-unix/ | sed -e s/^X//g | head -n 1`"

export TouchPadID=11

grep -q closed /proc/acpi/button/lid/*/state

xinput set-int-prop  $TouchPadID "Device Enabled" 8 $?