Ubuntu – Alps Loaded but PS/2 mouse also loaded!

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.

Well, this is not the direct answer, but a suggestion and examples. If you run xinput, you will get list of your devices. Then run xinput list-props $id where $id is your touchpad id in the list.

You will have a list of options like this:

$ xinput list-props 13
Device 'SynPS/2 Synaptics TouchPad':
    Device Enabled (135):   1
    Coordinate Transformation Matrix (137): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
    Device Accel Profile (268): 1
    Device Accel Constant Deceleration (269):   2.500000
    Device Accel Adaptive Deceleration (270):   1.000000
    Device Accel Velocity Scaling (271):    12.500000
    Synaptics Edges (292):  1765, 5371, 1637, 4453
    Synaptics Finger (293): 25, 30, 0
    Synaptics Tap Time (294):   180
    Synaptics Tap Move (295):   234
    Synaptics Tap Durations (296):  180, 180, 100
    Synaptics ClickPad (297):   1
    [...]

You can change all of these on-the-fly with xinput set-prop $id $propId $value where $id is the device id, $propId is property id in brackets and $value is what you want it to be. For example:

xinput set-prop 13 135 0 sets Device Enabled (135) to 0 and this will disable the touchpad.

You will need descriptions of properties and a way to make your changes permanent. Descriptions can be found in man synaptics, but wait, they are in another cryptic format! Let's see why.

To make changes permanent, you need to create conf file in /etc/X11/xorg.conf.d, for example 30-tochpad.conf with contents like these:

    Section "InputClass"  # you can read more in `man xorg`
            Identifier "all touchpads"  # just a name for this config
            MatchIsTouchpad "on"  # enables this config for all detected touchpads
            Driver "synaptics"  # enables synaptics-specific options below

            # This will disable the device
            #Option "Ignore" "1"

            # There are options that are generic for input-devices or mouse-like devices, see `man evdev`:
            Option "ButtonMapping" "0 0 0 0 0 0 0"  # i disabled all buttons here, for example

            # Here go options from `man synaptics`
            Option "VertTwoFingerScroll" "1"
            Option "HorizTwoFingerScroll" "1"
            Option "PalmDetect" "1"
            Option "ClickPad" "0"                
            # ...etc...
    EndSection

So, man synaptics describes options for xorg.conf and tells how they correspond to xinput list-props output.

PS. I tried to configure trackpoint on my ThinkPad X220 to have only two-fingers-scroll enabled, without clicks or mouse movement. I failed. Maybe you will manage to do what you want (there was an option to disable everything but clicks, maybe Synaptics Off).

Sources, more examples and unicorns:

https://wiki.ubuntu.com/X/Config/Input

https://wiki.archlinux.org/index.php/Touchpad_Synaptics