Adjust the speed of the trackpoint on a Lenovo Carbon X1

1. find the trackpoint device

$ find /sys/devices/platform/i8042 -name name | xargs grep -Fl TrackPoint | sed 's/\/input\/input[0-9]*\/name$//'
/sys/devices/platform/i8042/serio1/serio2

2. set an appropriate value

$ cat /sys/devices/platform/i8042/serio1/serio2/sensitivity 
128

$ echo 220 | sudo tee /sys/devices/platform/i8042/serio1/serio2/sensitivity
220