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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - Fake finger switching bug in edge scrolling and tapping code"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89949">89949</a>
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<th>Summary</th>
<td>Fake finger switching bug in edge scrolling and tapping code
</td>
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<th>Product</th>
<td>Wayland
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>ASSIGNED
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>libinput
</td>
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<th>Assignee</th>
<td>wayland-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>peter.hutterer@who-t.net
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<th>CC</th>
<td>jwrdegoede@fedoraproject.org
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=114942" name="attach_114942" title="evemu recording">attachment 114942</a> <a href="attachment.cgi?id=114942&action=edit" title="evemu recording">[details]</a></span>
evemu recording
To switch from one to two fingers on a touchpad without slots, the event
sequence is:
BTN_TOOL_FINGER 0
BTN_TOOL_DOUBLETAP 1
SYN_REPORT
On those touchpads, all touches are fake touches (sort-of). The above sequence
will end the currently active touch and then re-start two new touches when the
DOUBLETAP is seen. This triggers a bug message in the edge scrolling code -
since there is no SYN_REPORT between the BTN_TOOL the touch is still in AREA
state when it is re-triggered as a TOUCH_BEGIN.
This also affects the tapping code.
The sequence attached is enough to trigger it, full sequence in the bug here:
<a href="https://bugzilla.redhat.com/show_bug.cgi?id=1209151">https://bugzilla.redhat.com/show_bug.cgi?id=1209151</a></pre>
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