No cursor on Qt5 under linuxfb plugin



  • Dear,

    I have Qt5.1.0 running on a x86 embedded system, no xserver, no wayland. So I tried the linuxfb platform with the "evdevmouse" and "evdevkeyboard" plugins.
    It works quite well, apart from the fact that I can not see the mouse cursor. If I am lucky I can click the buttons and the application behaves as expected.
    I did try with
    @QApplication::setOverrideCursor(QCursor(Qt::CrossCursor));
    @

    in different variations without success.

    Here is my command line to start the application:
    @/demo-app -platform linuxfb -plugin evdevkeyboard:/dev/input/event0 -plugin evdevmouse:/dev/input/event1@

    Any Idea how to get the cursor visible?

    Thanks for any response!
    Thomas



  • Could you solve your problem?

    I just upgraded our software stack to QT 5.1.x. I was able to use mouse input with QT 4.8 and tslib without any problems but it doesn't seem to work with QT5.1.x.
    I use the default examples in qt to test input device support on our embedded system and I haven't been able to find a line of code which would disable the cursor in the examples. Therefore it must to be a wrong configuration...

    nice regards
    Michael

    EDIT: I just realized that in my case the moues also works. The cursor is just now shown.



  • Hello,

    I have exactly the same problem with Qt5.2.0-alpha, native build on a Beaglebone black (ubuntu distro): I don't see the mouse pointer but the mouse is working...
    I used : ./xyz -platform linuxfb -plugin EvdevMouse -plugin EvdevKeyboard
    (keyboard is working).

    Thanks,
    J.

    Same problem also on my Qt5.1.1 build



  • I visited die DevDays in Berlin and a developer mentioned in a presentation that this behavior can be modified by manipulating the QT_QPA_EGLFS_CURSOR environment variable. You also have to create a json-file which specifies all the settings, but currently there is no documentation about this, therefor you'd have to check the source-code: https://qt.gitorious.org/qt/qtbase/source/3d0af143ca51af0a3cbd81a794e6726992f9a86b:src/plugins/platforms/eglfs/qeglfscursor.cpp

    nice regards
    Michael



  • There is no mouse cursor visible with linuxfb because cursor support is somewhat incomplete in this plugin. I'm cooking up a patch for this so hopefully it will get corrected in 5.2 final.



  • To complete answer of Agocs, you may follow this bug:
    https://bugreports.qt-project.org/browse/QTBUG-30364

    You may found patch written by Agos there:
    https://codereview.qt-project.org/#change,67926
    Unfortunately, it's look like it's not included in Qt5.2.0.



  • The cursor fix is in 5.2.0. However, linuxfb has another bug in 5.2.0 which often prevents windows from showing up properly. It has recently been fixed ( https://codereview.qt-project.org/#change,74138 ) and the fix is coming in 5.2.1.



  • [quote author="agocs" date="1388512087"]The cursor fix is in 5.2.0. However, linuxfb has another bug in 5.2.0 which often prevents windows from showing up properly. It has recently been fixed ( https://codereview.qt-project.org/#change,74138 ) and the fix is coming in 5.2.1.
    [/quote]

    I tried an application (http://qt-project.org/forums/viewthread/47066/) with linuxfb and Qt 5.3.1 on Gentoo Linux, but there is no mouse cursor visible on framebuffer. If a Qpushbutton fills the whole screen, clicking the mouse aktivates the button, so the move seems to work. Is there a special command line option for configure to enable showing the mouse cursor?



  • I figured out that this is not related to QT 5.3.1. If I connect another mouse e.g. with cable the mouse cursor appears as expected if I choose the correct event device (/dev/input/...). But some wireless mice and touchpads are not working well. But this must be related to the evdev support(?).


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