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  1. Qt
  2. QTBUG-128724

[Linux] Single finger touch not registered

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    • Linux/X11

    Description

      There are some issues with touch events getting processed. The testing has been done with https://github.com/Witekio/qt-touchscreen-test and 3DSlicer examples.

      Double finger touches are registered as mouse events and single finger events get triggered only the first time one is made on the window. For this reason, subsequent single-finger touches have no effect. On Ubuntu 22.04 single finger touch worked correctly.

      It was also noticed while testing that if one finger was touching the screen somewhere, then Qt program responded to a new finger on the screen as if it were the only one. 

       

      This is the output when QT_XCB_DEBUG_XINPUT_DEVICES= 1 :

      input device "Atmel Atmel maXTouch Digitizer" ID 15
has 7 buttons
has valuator "Abs MT Position X" recognized? true
has valuator "Abs MT Position Y" recognized? true
has valuator "Rel Horiz Scroll" recognized? true
has valuator "Rel Vert Scroll" recognized? true
it's a scrolling device
has touch class with mode 1
unexpectedly missing RelVert/HorizWheel atoms for touchpad with scroll capability QPointingDevice("Atmel Atmel maXTouch Digitizer" TouchScreen id=15 seat=30002 ptrType=Finger caps=Position|NormalizedPosition|Scroll maxPts=10)
register QInputDevice(QPointingDevice("Atmel Atmel maXTouch Digitizer" TouchScreen id=15 seat=30002 ptrType=Finger caps=Position|NormalizedPosition|Scroll maxPts=10)
it's a touchscreen with type 2 capabilities 0x121 max touch points 10

      Attachments

        1. kde6-x11-output.txt
          20 kB
          Liang Qi
        2. u2404-x11-output.txt
          10 kB
          Liang Qi

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-91402 [REG: 5.15 - 6.x] Wheel events get lost when connecting from macOS via ssh

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
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              liaqi Liang Qi
              tiheikka Titta Heikkala
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              Dates

                Created:
                Updated:
                Resolved:

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