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      <base href="https://bugs.freedesktop.org/">
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    <body><span class="vcard"><a class="email" href="mailto:peter.hutterer@who-t.net" title="Peter Hutterer <peter.hutterer@who-t.net>"> <span class="fn">Peter Hutterer</span></a>
</span> changed
          <a class="bz_bug_link 
          bz_status_ASSIGNED "
   title="ASSIGNED - SynPS/2 Synaptics TouchPad detects fingers not touching the touchpad while using two-finger scrolling"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=105535">bug 105535</a>
          <br>
             <table border="1" cellspacing="0" cellpadding="8">
          <tr>
            <th>What</th>
            <th>Removed</th>
            <th>Added</th>
          </tr>

         <tr>
           <td style="text-align:right;">Depends on</td>
           <td>
                
           </td>
           <td>105258
           </td>
         </tr>

         <tr>
           <td style="text-align:right;">Status</td>
           <td>NEEDINFO
           </td>
           <td>ASSIGNED
           </td>
         </tr></table>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_ASSIGNED "
   title="ASSIGNED - SynPS/2 Synaptics TouchPad detects fingers not touching the touchpad while using two-finger scrolling"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=105535#c8">Comment # 8</a>
              on <a class="bz_bug_link 
          bz_status_ASSIGNED "
   title="ASSIGNED - SynPS/2 Synaptics TouchPad detects fingers not touching the touchpad while using two-finger scrolling"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=105535">bug 105535</a>
              from <span class="vcard"><a class="email" href="mailto:peter.hutterer@who-t.net" title="Peter Hutterer <peter.hutterer@who-t.net>"> <span class="fn">Peter Hutterer</span></a>
</span></b>
        <pre>oops, the range mismatch is fixed in master now (4ff5f02d9c). But the big thing
here is:

<span class="quote">> As for single-finger pointer motion - it's normal. Bug does not not appear there.</span >

Basically this means that the touchpad pressure changes when two fingers are
down. That's not good... Anyway, I bisected this and came up with: commit
3979b9e16a5ed141506d95f80ddfd7b94651dcfa. Basically the problem is that we now
assume that when we have more fingers down than the touchpad can individually
detect (>1 for semi-mt devices) then we assume all fingers have an
above-threshold pressure value.

This matches the data in the evemu recording, the pressure is well below the
thresholds yet we treat it as down. Should be fixable.</pre>
        </div>
      </p>

        <div id="referenced">
          <hr style="border: 1px dashed #969696">
          <b>Referenced Bugs:</b>
          <ul>
              <li>
                [<a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED FIXED - libinput crashes Xorg with SIGABRT in tp_tap_handle_state() [evdev-mt-touchpad-tap.c:1030|1028]"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=105258">Bug 105258</a>] libinput crashes Xorg with SIGABRT in tp_tap_handle_state() [evdev-mt-touchpad-tap.c:1030|1028]
              </li>
          </ul>
        </div>
        <br>

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