Ubuntu – Why does the “Mouse” preferences GUI not allow me to enable two-finger scrolling

First of all, to identify which touchpad you have, run

xinput list 

If it shows something like

...
↳ AlpsPS/2 ALPS GlidePoint                  id=14   [slave  pointer  (2)]
...

then you most probably do not have multitouch support. The Alps touchpads tend not to have multitouch, while they use the same driver as the Synaptic touchpads.

You can use synclient -l to obtain information on your touchpad.

Still, the definitive way to see how many fingers are supported on your touchpad, is to

1. Enable SHMConfig in your xorg.conf file
2. Run synclient -m 100, which will show in real time the status of your touchpad. The fifth column labeled f is for fingers, therefore you can see up to how many fingers you can tap at the same time.

To enable SHMConfig in xorg.conf, see http://mjg59.livejournal.com/118588.html and then add

Section "InputClass"
   Identifier "enable synaptics SHMConfig"
   MatchIsTouchpad "on"
   MatchDevicePath "/dev/input/event*"
   Option "SHMConfig" "on"
EndSection

to your xorg.conf. You can remove the above snippet once you performed your testing.

To get your synclient settings to stick you can add them to xorg.conf. I did this recently for my macbook pro in 12.10 and it works pretty well.

You can also specify a separate configuration file in /etc/X11/xorg.conf.d/ file to keep things neater. Here's a step by step:

1. Create /etc/X11/xorg.conf.d (if it doesn't already exist)

   sudo mkdir /etc/X11/xorg.conf.d

2. Create and edit /etc/X11/xorg.conf.d/10-synaptics.conf

   gksudo gedit /etc/X11/xorg.conf.d/10-synaptics.conf

3. Make it look like the following:

   #Sample /etc/X11/xorg.conf.d/10-synaptics.conf
   Section "InputClass"
     Identifier "touchpad catchall"
     Driver "synaptics"
     MatchDevicePath "/dev/input/event*"
     MatchIsTouchpad "true"
     Option  "SHMConfig"           "true"
     Option  "TapButton1"          "1"
     Option  "TapButton2"          "2"
     Option  "TapButton3"          "3"
   EndSection
   

4. Save and logout/login again. If the xserver fails to load and you get forced into low graphics mode then edit the file again and comment everything out, or mv /etc/X11/xorg.conf.d/10-synaptics.conf ~/10-synaptics.conf.backup and reload again to get back to normal.

For posterity, my current setup for my macbook pro 2012 13" is as follows (warning, I like my touchpad rather sensitive). Try any of these options using synclient before putting them into xorg.conf!

Section "InputClass"
      Identifier "touchpad catchall"
      Driver "synaptics"
      MatchIsTouchpad "on"
      MatchDevicePath "/dev/input/event*"
      MatchProduct "bcm5974"
      MatchIsTouchpad "true"
      Option  "SHMConfig"           "true"
      Option  "FastTaps"            "1"
      Option  "MaxDoubleTapTime"    "100"
      Option  "BottomEdge"          "6000"
      Option  "FingerLow"           "60"
      Option  "FingerHigh"          "90"
      Option         "ClickFinger3" "2"
#      Option         "FingerLow"             "30"
#      Option         "FingerHigh"            "80"
      Option         "VertTwoFingerScroll" "1"
      Option         "HorizTwoFingerScroll" "1"
      Option         "VertScrollDelta" "100"
      Option         "HorizScrollDelta" "100"
      Option         "MultiFingerButton" "2"
      #Option         "TapButton1" "1"
      Option         "TapButton2" "3"
      Option         "TapButton3" "2"
      Option         "MinSpeed" "1"
      Option         "MaxSpeed" "2"
      Option         "AccelFactor" "0.01"
#      Option         "AreaBottomEdge" "5000"
EndSection