[Interest] Slow touchscreen (eGalax) response in QML using evdevtouch plugin and eglfs platform

Georgije Bosiger gbosiger at gmail.com
Tue May 27 15:06:00 CEST 2014

>From what I've seen it turns out that the problem is in "onPositionChanged"
signal. For some reason attached handler to this signal is not executed on
faster movements when evdevtouch is used, but it's OK for the evdevmouse.
This realization lead me to use the timer instead, so that now I make
changes on defined interval while touch is pressed. This way response to
the input is fast.

Best regards,

2014-05-23 16:14 GMT+02:00 Georgije Bosiger <gbosiger at gmail.com>:

> Hi,
> I have an embedded linux device with AM335x CPU on which I am running QML
> applications using the eglfs platform. The Qt library version is 5.1. For
> the input I have a touch panel with usb egalax controller that is used by
> the evdevtouch plugin. Input works, but the problem is in performance. Only
> slow movements are followed - on faster movements the position is updated
> only on stop.
> This behaviour can be seen even by simple QML app that writes the
> coordinates on the screen. I have no problem if I use the mouse. If I run
> the "ts_test" from tslib the touch screen works fine, so I guess the reason
> is not in the driver.
> Has anyone experienced a similar issue or has a clue what can be done?
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