How to make X use gpm to read from Synaptics touchpads

• Download the source package gpm-1.19.6.tgz
• Untar it in some suitable place
• Enter the "gpm-1.19.6/src" directory
• Apply this patch to "synaptics.c".
• This will apply the following changes:
• Modify the coordinates of the edges to better fit the observed values - no more trouble activating the right edge!
• Always enable "W mode" if your device is capable of it
• Prevent seemingly faulty "middle mouse button" responses
• Map "Scroll-Left" to left mouse button, "Scroll-Up" to middle mouse button and "Scroll-Right" to right mouse button.
• Prevent click response if more than one finger touches the pad.
• Enable some debug info be printed to stderr on startup.
  

• Install, as per "gpm-1.19.6/INSTALL" (it's standard GNU/autoconf stuff)
  
• The driver has many configurable options, outlined in the "synaptics.c" source file. They are read from a file in "<INSTALL-PREFIX>/etc/gpm-syn.conf". My "gpm-syn.conf" file reads:

[ use_wmode y ]
[ tossing_enabled n ]
[ min_toss_time 10 ]
[ max_toss_time 300 ]
[ min_toss_dist 15 ]
[ corner_taps_enabled n ]
[ low_pressure 40 ]
[ speed_up_pressure 40 ]


Most of those options are rather personal, of course.

• Modify your /etc/rc.d/init.d/gpm or equivalent to start gpm with these options:

gpm -R msc -t synps2

• Make X read from the gpm repeater stream with an InputDevice section like this:

Section "InputDevice"
        Identifier  "Mouse0"
        Driver      "mouse"
        Option      "Protocol" "MouseSystems"
        Option      "Device" "/dev/gpmdata"                      Option      "Buttons" "3"
        Option      "Emulate3Buttons" "no"
EndSection


• As you can see, I do not you special corner commands. I haven't yet figured out a way to put the four way scroll button to more general use, but I'm quite happy to have a usable middle mouse button.