First off, let me say that I am extremely appreciative of each of you posting your thoughts and ideas on this forum. Secondly, yes, this does pertain to the Linux framebuffer "fbdev" drivers. I have a small (128x160 resolution) TFT LCD attached to my RPi via GPIO pins, and have it attached to /dev/fb1. I followed this tutorial to get the drivers working.
Arthur, I appreciate you writing a demo for me. One thing I've noticed from examining the source files is that there is no GLES directory on Allegro 5.0.6. So, when I tried your demo, it threw me an error saying... "In file included from main.cpp:4:0:/usr/local/include/allegro5/allegro_opengl.h:63:21: fatal error: GLES/gl.h: No such file or directory compilation terminated." So, allegro_opengl.h is including GLES/gl.h, but that doesn't exist as far I can see on 5.0.6.
I took a look at the 5.0.9 release and couldn't find GLES there either. Perhaps I'm blind?