Mouse not working on frame buffer sample project

Andrej_Viktorovich · December 16, 2020, 7:32pm

Hello,

I have 7’ touchscreen display and mouse connected to my Pi4. Both of these pointing devices not working in sample project that runs on frame buffer. Why? How to fix that?

embeddedt · December 16, 2020, 8:55pm

Take a look at these:

github.com

lvgl/lv_port_linux_frame_buffer/blob/6232acdcc394878dd9155fd12a622b20358da7bc/lv_drv_conf.h#L328


#endif  /*USE_LIBINPUT*/

/*-------------------------------------------------
 * Mouse or touchpad as evdev interface (for Linux based systems)
 *------------------------------------------------*/
#ifndef USE_EVDEV
#  define USE_EVDEV           0
#endif

#if USE_EVDEV
#  define EVDEV_NAME   "/dev/input/event0"        /*You can use the "evtest" Linux tool to get the list of devices and test them*/
#  define EVDEV_SWAP_AXES         0               /*Swap the x and y axes of the touchscreen*/

#  define EVDEV_SCALE             0               /* Scale input, e.g. if touchscreen resolution does not match display resolution */
#  if EVDEV_SCALE
#    define EVDEV_SCALE_HOR_RES     (4096)          /* Horizontal resolution of touchscreen */
#    define EVDEV_SCALE_VER_RES     (4096)          /* Vertical resolution of touchscreen */
#  endif  /*EVDEV_SCALE*/

#  define EVDEV_CALIBRATE         0               /*Scale and offset the touchscreen coordinates by using maximum and minimum values for each axis*/
#  if EVDEV_CALIBRATE

You can use evtest /dev/input/<device> to find which device has which ID.

rpcy · December 16, 2020, 9:12pm

Also, you have to have the 7" display powered via USB cable from the Pi itself, because that is the signaling path by which the touchscreen sends its touch position information back to the Pi. There’s a driver in the Raspberry Pi OS that thinks that incoming USB data is from a mouse.

On the lvgl demo code, my 7" touchscreen is correctly registering my screen touches.

Andrej_Viktorovich · December 17, 2020, 9:29am

I have connected touchscreen to Pi via USB and it reacts on touch on Raspbian desktop. I also have mouse connected on USB. But when I switch to console (Ctrl+Alt+F1) and run ./demo it does not reacts to any mouse or touchscreen input.

Andrej_Viktorovich · December 17, 2020, 1:19pm

Hello, looks like link to button sample is corrupted