Getting error when trying to run demo file "unable open evdev interface:: No such file or directory"

[jojomojo93]

Hi,

Thank you for sharing the files and steps required to get lvgl demo running on RPi.

I have RPi 3B+ with Rasbian OS installaed nad updated. I've followed the instructions you've mentioned to get lvgl demo running. However, when I try to run the demo file - using "sudo ./demo", I get the following error: "pi@raspberrypi:~/Desktop/test1/lvgl_demo $ sudo ./demo The framebuffer device was opened successfully. 656x416, 32bpp The framebuffer device was mapped to memory successfully. unable open evdev interface:: No such file or directory"

[dronecz]

Hi @jojomojo93,

I´m no linux guru so I´m maybe mistaken but it looks like you do not have "input" device detected (here is function evdev_nit())

I would try comment this line out ( // evdev_init(); ) which should work. Second thing which I would try is list all input devices (look here for more info)

Please let us know if you solved it 😉

[jojomojo93]

Hi @dronecz , Thank you for your reply. I've commented the initialization of evdev function as you mentioned - I'm accessing the rpi through remote desktop no display is connected and no touch sensor is there.

Now there is no error when executing the demo as root but I don's see any window is opening - I'm referring to the examples or widgets window.

I've managed to get lvgl pc simulator example running on my rpi and that will do for now.

[dronecz]

Ok, I´m planning to try this as well so I will let you know how it goes.

How did you manage to make example from simulator work? Thanks

[jojomojo93]

@dronecz I used the one in this link and it is working fine on my rpi. https://github.com/lvgl/lv_sim_eclipse_sdl

[BasicCode]

I was experiencing the same problem. For me it was just that the EVDEV_NAME was wrong, but I didn't notice: https://github.com/lvgl/lv_port_linux_frame_buffer/blob/master/lv_drv_conf.h#L450 For me (and a lot of systems I think) the path should be /dev/input/event0.