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

[Phil Hannent]

Hi,

I have had experience with touch screens. The best place to start in my
view is looking at the number of events and their frequency from the
device. In my experience some equipment slows down the number of events it
generates as you perform more complex/faster movements.

I was working on something similar a year ago:
http://stackoverflow.com/questions/11509140/touchscreen-sample-rate-for-human-interface-device

Regards
Phil


On 23 May 2014 15:14, Georgije Bosiger <gbosiger at gmail.com> wrote:

> 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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