Ubuntu – Synaptics touchpad keeps scrolling after letting go of the touchpad in Ubuntu

driversscrollingsynaptics-touchpadUbuntu

Since switching from Fedora to Ubuntu, I have a pretty annoying problem with my Synaptics Touchpad which is built into my Thinkpad X220. When I use the two-finger scrolling functionality, it's as though the scroll events are "queued up" and keep happening even after I've completely removed my fingers from the touchpad. It's especially bad when browsing, since when I switch tabs with Ctrl+Tab, the pressing Ctrl—together with the scroll events which keep going—regularly zooms all the way in or out of webpages.

I haven't had this problem in Fedora, so I'm unsure what the difference is, since it should be the same driver for all I know. I've looked into some settings the driver has and which can be set via Xorg, but all that man synaptics tells me is:

The MinSpeed, MaxSpeed and AccelFactor parameters don't have any effect on scrolling speed. Scrolling speed is determined solely from the VertScrollDelta and HorizScrollDelta parameters.

Which is odd, since the behaviour I described seems just like there's some acceleration for the scrolling happening. So I'm out of ideas on how to go about this.

Best Answer

I actually found out the answer to this after searching through a lot more questions and answers on StackExchange sites and forums. It's a feature referred to as "Coasting", which I didn't find out about before because I was specifically just searching for "scrolling" (and not "scroll" as well).

Here's the relevant bits from man synaptics:

Option "CoastingSpeed" "float"

Your finger needs to produce this many scrolls per second in order to start coasting. The default is 20 which should prevent you from starting coasting unintentionally. 0 disables coasting. Property: "Synaptics Coasting Speed"

Option "CoastingFriction" "float"

Number of scrolls/second² to decrease the coasting speed. Default is 50. Property: "Synaptics Coasting Speed"

So for me personally I just set CoastingSpeed to 0 and that fixes the problem.

Related Solutions

Linux – How to make Synaptics touchpad work better on Linux

Assuming you are using a recent X server that supports udev and are using udev input driver. The most likely cause is that the synaptics is being used as a generic mouse. Try adding the following to your xorg.conf file.

Section "InputClass"
    Identifier "synaptics"
    MatchIsTouchpad "on"
    Driver "synaptics"
    Option "VertTwoFingerScroll" "on"

EndSection

Linux – Elementary OS Luna 0.2 Synaptics Touchpad settings persistent

The short answer is yes, and by using:

synclient TapButton2=2

But this will only work until you reboot or shutdown, to make the changes persistent follow these few easy steps.

I found this Source to be very helpful.
Note: This has worked for all my Debian/Ubuntu based distributions.

These are the steps I took:

Setp 1: To determine your type of touchpad run the following command:

egrep -i 'synap|alps|etps' /proc/bus/input/devices

My output:

N: Name="SynPS/2 Synaptics TouchPad"

As you can see I have a 'Synaptics' type touchpad.

Step 2: To determine whether your touchpad will accept multitouch taps or not, run the following command:

grep "TouchPad: buttons:" /var/log/Xorg.0.log

My output:

[     7.480] (--) synaptics: SynPS/2 Synaptics TouchPad: buttons: left right double triple

This shows that my touchpad will accept 'double' and 'triple' finger taps. If you only see 'left' and 'right' listed, then your touch-pad does not support multi-touch.

Step 3: Current settings and Testing your new set-up.

To see what settings you currently have run:

synclient -l

You'll then get a long list of all the current settings for 'synclient', the one's your interested in are:

TapButton1              = 1
TapButton2              = 3
TapButton3              = 0

'TapButton1' is a single/(one) finger tap
'TapButton2' is a double/(two) finger tap
'TapButton3' is a triple/(three) finger tap

The number after the '=' refer to the function executed by that type of tap.

'= 0' - disabled
'= 1' - 'left click' button function
'= 2' - 'middle' mouse button function
'= 3' - 'right click' button function

As you can see from the current settings the 'two-finger' tap is set to being*'right click'*. To change this to being the 'middle click' you'll need to change the 'TapButton2 = 3' to '= 2', do this using the following command:

synclient TapButton2=2

Now you should be able to use your touch-pad to do a two-finger tap to paste the most recent highlighted text under the mouse courser.

Step 4: Saving settings.

Your current changes will only work until your next shutdown or reboot. To save your settings you'll need to find where the settings are stored:

ls /usr/share/X11/xorg.conf.d

Output:

10-evdev.conf  11-evdev-quirks.conf  11-evdev-trackpoint.conf  50-synaptics.conf  50-synaptics.conf~  50-vmmouse.conf  50-wacom.conf  51-synaptics-quirks.conf  glamoregl.conf

Here the '50-synaptics.conf' file is the one we are interested in. Open as admin:

sudo scratch-text-editor /usr/share/X11/xorg.conf.d/50-synaptics.conf

sudo gedit /usr/share/X11/xorg.conf.d/50-synaptics.conf

Enter your password when prompted and add the following line just under the 'Section "InputClass" ' line and click save

    Option          "TapButton2"            "2"

Next time you boot you should be able to use 'double tap' as 'middle-click'.

Best Answer

Related Solutions

Linux – How to make Synaptics touchpad work better on Linux

Linux – Elementary OS Luna 0.2 Synaptics Touchpad settings persistent

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