When Keyboard Key is in Hold, then Webvisu is extreme slow and latent

  • Tyro - 2023-01-16

    Hello Everybody,

    i have a very special problem!

    The System is

    Rasperry Pi 4
    Codesys MC for Raspberry 4.6 with Webvisu per Touchscreen.

    I am reading the Keyboard events with evdev for some other things. The problem is when a keyboard Key is on hold, Codesys Touch Screen reaction is extreme latent/slow. Though i can see in events log that the touch events are registered.
    Any Help!

  • richard-wang - 2023-09-05

    Hi Tyro
    Did you resove your problem? I have the same issue.



  • TimvH

    TimvH - 2023-09-20

    I'm not really sure what you are trying to do, but maybe you are referring to using the CmpCharDevice library?

    When you "open" the connection to a device, you can pass flags. What helped me is to set the non-blocking flag.

    I'm not sure if this is what you are referring to, but maybe it helps:

    dFlags: DINT := CmpCharDevice.ACCESS_MODE.O_RDONLY + DINT#4000; // see details for flags: http://linux.die.net/man/2/open, + DINT#4000 is for non-blocking
    hDevice := CmpCharDevice.CDOpen(szFilename, dFlags, Result);

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