LVGL on top of Linux graphics stack

Example project to use LVGL on top of Linux graphics stack. Currently supported backends are either legacy framebuffer (fbdev), modern DRM/KMS, or SDL2.

By default, legacy framebuffer backend uses /dev/fb0 device node, DRM/KMS backend uses '/dev/dri/card0' card node, SDL2 uses window resolution of 800x480.

Check out this blog post for a step by step tutorial: https://blog.lvgl.io/2018-01-03/linux_fb

Clone the project

Clone the LVGL Framebuffer Demo project and its related sub modules.

git clone https://github.com/lvgl/lv_port_linux_frame_buffer.git
cd lv_port_linux_frame_buffer/
git submodule update --init --recursive

Select graphics backend (optional)

To use legacy framebuffer (fbdev) support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	1
#define LV_USE_LINUX_DRM	0
#define LV_USE_SDL		0

To use modern DRM/KMS support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	0
#define LV_USE_LINUX_DRM	1
#define LV_USE_SDL		0

To use SDL2 support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	0
#define LV_USE_LINUX_DRM	0
#define LV_USE_SDL		1

Build the project

mkdir build
cd build 
cmake ..
make -j

Environment variables

Environment variables can be set to modify behavior of the demo. The following variables are supported.

Legacy framebuffer (fbdev)

• LV_LINUX_FBDEV_DEVICE - override default (/dev/fb0) framebuffer device node.

DRM/KMS

• LV_LINUX_DRM_CARD - override default (/dev/dri/card0) card.

SDL2

• LV_SDL_VIDEO_WIDTH - width of SDL2 surface (default 800).
• LV_SDL_VIDEO_HEIGHT - height of SDL2 surface (default 480).

Run the demo application

As root

Normal users don't have access to /dev/fb0 so use sudo (or see below) :

cd ../bin
sudo main

Userland

You can give a normal user access to the framebuffer by adding them to the video group :

sudo adduser $USER video
newgrp video
cd ../bin
./main

Notes

• The Makefile is broken right now, so Cmake shall be used.