Common Issues

Qt Sensors: Sensor Support Depends on Hardware

The reference devices have no built-in sensor hardware.

Note: Sensors can be tested on emulator targets.

Qt WebEngine: Widget-based Web View not Available

The Qt WebEngine API are available only for Qt Quick 2 based applications at the moment. The QWidget-based equivalent, such as QWebEngineView, will become supported in a future release. For the time being, use the WebEngineView QML type.

Limited Support for Multiple Top-Level Windows

OpenGL and Qt Quick 2 applications can only have one full screen window existing at a time. Trying to create another OpenGL window, or trying to mix an OpenGL window with a raster one will display an error message and abort the application.

Note: Raster windows (software rendered content based on QWidget or QPainter) do not have this limitation.

QML Debugging not Functional with Qt Quick Compiler

QML debugging is not fully functional when Qt Quick Compiler is enabled. Support for this is planned for a later release.

Error: Failed to establish an ADB connection to the device

From Qt 5.9.0 onwards, the failing ADB connection error messages described in QTBUG-60736 will be seen in the Qt Creator General Messages tab when using the emulator. The error note appears if your development host has both Boot to Qt 5.9.0 (or later) and Qt 5.8.0 (or older).

You can safely ignore the error messages if the emulator works correctly. The error messages do not appear if you uninstall Boot to Qt 5.8.0 (or older) from your development host.

I receive a SIGILL signal from OpenSSL when I debug my application

Even though your application works without errors in release mode, you may receive a SIGILL signal from OpenSSL when you debug your application.

This is a known issue in OpenSSL. For more information, see https://www.openssl.org/docs/faq.html#PROG15.

You can use the following work-arounds:

• In Qt Creator, select Tools > Options > Debugger > GDB and write set handle SIGILL nostop to Additional Startup Commands.
• Set the value of the environment variable OPENSSL_armcap to ARMV7_NEON Relevant.

Device-Specific Issues

BD-SL-i.MX6: Device Stops Working After Disconnecting the Micro-USB Cable

The device does not respond to touch input after connecting to a host computer via USB, and then disconnecting the Micro-USB cable.

Ixora Carrier Board Connected Over USB Is Not Always Detected

The Ixora carrier board connected over USB is not detected if a jumper JP2 is placed in. The jumper JP2 is located between the USB ports in the carrier board.

For more information about the jumper JP2 in the Ixora carrier board, see the chapter 3.5 in http://docs.toradex.com/104004-apalis-arm-ixora-datasheet-v1-1.pdf.

Emulator-Specific Issues

Qt WebEngine not Available for Emulator

Qt WebEngine will not be available on the emulator.

Switching Between Emulators from Different Boot to Qt Versions

Switching between multiple Boot to Qt virtual machines is likely to introduce instability, emulator startup problems and graphical issues. To avoid these problems, close the previous emulator before launching a new one.

Multi-process Support with the Wayland Windowing System

Wayland support is currently in an experimental stage. On i.MX6-based devices it is possible to run the Weston compositor and run Qt applications as Wayland clients. The main limitations are:

1. Graphical performance is limited. This is especially true when running multiple applications at the same time. Tearing and various rendering glitches can also be expected. Future versions of the vendor-provided graphics drivers and board support packages are expected to improve on this.
2. Touch input will not be functional in Qt applications. This will be corrected in the upcoming releases.
3. The Qt Virtual Keyboard is fully functional but will show up on a per-window basis inside the application window. A global virtual keyboard solution using Wayland's text input protocol will be available in the future.
4. The compositor will likely crash in certain situations. The stability is expected to be improved in newer versions of Weston and the vendor-provided BSP.
5. Tooling: running and especially debugging applications from Qt Creator may have issues when the applications are running as Wayland clients. Support for this will be improved in future releases.