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            <b><a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED MOVED - touchpad (on X220) less precise when moving in from the edges"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=94989#c18">Comment # 18</a>
              on <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED MOVED - touchpad (on X220) less precise when moving in from the edges"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=94989">bug 94989</a>
              from <span class="vcard"><a class="email" href="mailto:mbiebl@gmail.com" title="Michael Biebl <mbiebl@gmail.com>"> <span class="fn">Michael Biebl</span></a>
</span></b>
        <pre>running touchpad-edge-detector, I get

$ sudo touchpad-edge-detector /dev/input/event5
Touchpad SynPS/2 Synaptics TouchPad on /dev/input/event5
Move one finger around the touchpad to detect the actual edges
Kernel says:    x [1472..5472], y [1408..4448]
Touchpad sends: x [1316..5626], y [1355..4826] \^C

Touchpad size as listed by the kernel: 53x23mm
Calculate resolution as:
        x axis: 4000/<width in mm>
        y axis: 3040/<height in mm>

Suggested udev rule:
# <Laptop model description goes here>
evdev:name:SynPS/2 Synaptics
TouchPad:dmi:bvnLENOVO:bvr8DET72WW(1.42):bd02/18/2016:svnLENOVO:pn42914CG:pvrThinkPadX220:rvnLENOVO:rn42914CG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:*
 EVDEV_ABS_00=1316:5626:<x resolution>
 EVDEV_ABS_01=1355:4826:<y resolution>
 EVDEV_ABS_35=1316:5626:<x resolution>
 EVDEV_ABS_36=1355:4826:<y resolution></pre>
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