I am using Ubuntu 14.04 on Lenovo ThinkPad S431. The touchpad is very bumpy, tricky to use. Slides down with a small touch, sometimes jerks erratically. I have tried to modify the settings in /usr/share/X11/xorg.conf.d/50-synaptics.conf file as below --

Section "InputClass"
    Identifier "touchpad catchall"
    Driver "synaptics"
    MatchIsTouchpad "on"
    MatchDevicePath "/dev/input/event*"
    Option "JumpyCursorThreshold" "250"
    Option "VertResolution" "100"
#   Option "HorizResolution" "65"
#   Option "MinSpeed" "1"
#   Option "MaxSpeed" "1"
#   Option "AccelerationProfile" "1"
#   Option "AdaptiveDeceleration" "8"
#   Option "ConstantDeceleration" "1"
#   Option "VelocityScale" "128"
    Option "HorizHysteresis" "150"
    Option "VertHysteresis" "150"
EndSection

There are lots of options here, does anyone know how to get a fine-tuned values for the above options (for ThinkPad S431)? The Hysteresis values seems to alleviate the problem a little bit, but failed to get a perfect result.

EDIT:

According to this bug report for ThinkPad X230 (+X230t), I set these values and quite good for now --

Option "VertResolution" "100"
Option "HorizResolution" "65"
Option "MinSpeed" "1"
Option "MaxSpeed" "1"
Option "AccelerationProfile" "2"
Option "AdaptiveDeceleration" "16"
Option "ConstantDeceleration" "16"
Option "VelocityScale" "32"
Option "HorizHysteresis" "50"
Option "VertHysteresis" "50"

and then you need to increase the cursor speed manually from the Unity mouse settings.

But I am still looking for a fully functional (possibly with all the gestures) and a fine-tuned touchpad settings for S431.

Further help is appreciated.