<html>
    <head>
      <base href="https://bugs.freedesktop.org/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - Touch points get out of sync with single touch devices; clients stop receiving events"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=69759">69759</a>
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>wayland-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Touch points get out of sync with single touch devices; clients stop receiving events
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>critical
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>ullysses.a.eoff@intel.com
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>weston
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Wayland
          </td>
        </tr></table>
      <p>
        <div>
        <pre>In corollary to <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - Touch events dropped after multiple touchpoints hit at once"
   href="show_bug.cgi?id=67563">Bug 67563</a>, I can trigger weston to stop processing touch events
with a single touch device.  It's hard to trigger, but by rapidly tapping the
screen in random places, Weston eventually gets into a state where it stops
sending touch events to the clients.

After a little debugging, I found that input.c::notify_touch() gets invoked
with a value of WL_TOUCH_UP by evdev.c::evdev_process_key() twice in a row when
seat->num_tp==1 prior to the first WL_TOUCH_UP.  This results in seat->num_tp
getting decremented too many times, hence halting client touch notifications. 
In other words, the number of invocations of notify_touch(WL_TOUCH_DOWN) and
notify_touch(WL_TOUCH_UP) are not symmetric.  Beyond this, I'm not sure what
triggers evdev_process_key() to handle two BTN_TOUCH 0 events in a row... since
evtest BTN_TOUCH 1 and BTN_TOUCH 0 events appear to be symmetric.

evtest logs are forthcoming.</pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are the assignee for the bug.</li>
      </ul>
    </body>
</html>