evdevtouch: Could not read from input device (No such device)



  • I am running a Qt Application on Nitrogen board. I have connected a HDMI supported Multi Touchscreen monitor to the Nitrogen board, and my Qt application is working fine on the touchscreen.

    But intermittently am noticing this error on the console

    evdevtouch: Could not read from input device (No such device)
    

    ... and touch user interaction is not getting recognized at that point.
    Any suggestion why this is happening ?

    Thanks in advance.


  • Lifetime Qt Champion

    Hi,

    Do you mean that your application is running fine for some time and then suddenly the input device disappears ?



  • @SGaist Yes. Some times the input device auto recovers and some times I keep noticing the above error in the console and input device is not responding.

    Basically my Qt application contains a ChartView QML item which displays a simple LineSeries and I am trying to add a marker on the ChartView area - which gets displayed when user clicks any point on the graph. When I try to click on a point in the graph area and try to drag the marker I am noticing this error intermittently.

    evdevtouch: Could not read from input device (No such device)
    No release received for 1 touch points over QQuickMouseArea(0x106da90, parent=0x101dc08, geometry=0,0 1223x659) on touch end.
    

    This error is not occurring all the time. Am worried if I messed up something.


  • Lifetime Qt Champion

    Are you disconnecting something when that message occurs ?



  • @SGaist No, am not disconnecting anything.


  • Lifetime Qt Champion

    Looks like there's something happening to your device rather than a problem with your application.



  • @chaithubk
    Are you reading from your device

    1. continously
      or
    2. just reading from it when device notifies you that data has arrived

    In the scenario 1 device will misbehave like you have mentioned


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