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  1. Qt
  2. QTBUG-96530

MTU changed for wrong GATT session - warning on Windows BT LE

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    Details

    • Type: Bug
    • Status: Reported
    • Priority: P3: Somewhat important
    • Resolution: Unresolved
    • Affects Version/s: 6.2.0 Beta4
    • Fix Version/s: None
    • Labels:
      None
    • Environment:
      Windows 10, Windows build 19042.1110
    • Platform/s:
      Windows

      Description

      Sometimes when using BT LE on Windows with logging categories enabled
      (QT_LOGGING_RULES=qt.bluetooth*=true) I see the warning message:

      "qt.bluetooth.windows: Got MTU changed event for wrong GattSession."

      Please find the application I used to reproduce it attached. It is a modified version of the lowenergyscanner example application that allows connecting to multiple LE perhipheral devices at the same time (service discovery is not enabled though).

      It is not easy to reproduce but I've seen it happen several times during the course of some hours while using the application. The only suspicion I have is that it might be related to the remote device disconnecting the session. As an example of more whole logging:

      qt.bluetooth: QLowEnergyControllerPrivate setting state to QLowEnergyController::UnconnectedState
      === Device::deviceDisconnected
      qt.bluetooth.windows: QLowEnergyControllerPrivateWinRT::onMtuChange
      qt.bluetooth.windows: mtu determined to be 23
      qt.bluetooth.windows: QLowEnergyControllerPrivateWinRT::onMtuChange
      qt.bluetooth.windows: Got MTU changed event for wrong GattSession.
      qt.bluetooth.windows: Unregistering  0  value change tokens
      qt.bluetooth.windows: QLowEnergyControllerPrivateWinRT::unregisterFromStatusChanges
      qt.bluetooth.windows: QLowEnergyControllerPrivateWinRT::unregisterFromMtuChanges
      Device::errorReceived
      

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            Assignee:
            andreasbuhr Andreas Buhr
            Reporter:
            vuokko Juha Vuolle
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              Dates

              Created:
              Updated:

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