I think i've made some progress, but the events from the mouse are not always managed.
I have added the uinput module to the Linux kernel (make menuconfig)
I have created a node as explained in the documentation of x11vnc ( http://www.karlrunge.com/x11vnc/x11vnc_opts.html#opt-pipeinput )
I start the vncserver firstly with the following command:
x11vnc -noipv6 -clip 500x500+0+0 -rawfb /dev/fb0 -pipeinput UINPUT:direct_abs= /dev/input/uinput (-dp -dk) &
After that i've checked the /dev/input and noticed that a char node called event0 was created (/dev/input/event0)
Then i can start my Qt5 application like this:
./myApp -geometry 500x500 -platform linuxfb -plugin evdevmouse:/dev /input/event0
Then i can move from one button to another using UP,DOWN,LEFT and RIGHT Key. I can push the buttons using the SPACE button ... that's cool my Application works correctly (^_^)/, but still no click :-( ... still looking...
Do you plan to bump your version of websocket based VNC on top of official Qt VNC plugin? It would be great because it's a great feature to get rid of any specific software to access embedded screenless device.