Hi jie,
To specify the display device, use the environment variable FB_FRAMEBUFFER_n, where n = any positive
integer. Example usage syntax:
export FB_FRAMEBUFFER_0=/dev/fb0
export FB_FRAMEBUFFER_1=/dev/fb1
export FB_FRAMEBUFFER_2=/dev/fb2
To open a specific framebuffer device, set environment variables to their proper values (e.g., set
FB_FRAMEBUFFER_0 = /dev/fb0). If there are no environment variables set, the driver will try to use the
default fb devices (fb0 for index 0, fb1 for index 1, fb2 for index 2).
Hope this helps