1.15. Framebuffer support

1.15.1. Framebuffer splash screen

barebox supports BMP and PNG graphics using the splash - display a BMP or PNG splash image command. barebox currently has no support for backlights, so unless there is a board specific enable hook for enabling a display it must be done manually with a script. Since barebox has nothing useful to show on the framebuffer it doesn’t enable it during startup. A framebuffer can be enabled with the enable parameter of the framebuffer device:

fb0.enable=1

Some framebuffer devices support different resolutions. These can be configured with the mode_name parameter. See a list of supported modes using devinfo fb0. A mode can only be changed when the framebuffer is disabled.

A typical script to enable the framebuffer could look like this:

#!/bin/sh

SPLASH=/path/to/mysplash.png

if [ ! -f $SPLASH ]; then
    exit 0
fi

# first show splash
splash /path/to/mysplash.png

# enable framebuffer
fb0.enable=1

# wait for signals to become stable
msleep 100

# finally enable backlight
gpio_direction_output 42 1

1.15.2. Framebuffer console

barebox has framebuffer console support which can be enabled with CONFIG_FRAMEBUFFER_CONSOLE. When registered each framebuffer device gets a corresponding fbconsole device. The console can be activated with fbconsolex.active=oe. Depending on compile time options there are different fonts available. These can be selected with the fbconsolex.font variable. To get a list of fonts use devinfo fbconsolex.