My google-foo is weak, and the results I find seem to be to hard for me to follow.
But what exactly is DirectFB or more closely how does it differ itself from X and 'just' FB.
I always thought that mesa 'needs' X to be able to supply opengl support, now I read 'directfb uses mesa for opengl', it's all just a bit confusing, and if directFB is so awesome, why do we need X at all?
I know that directFB is quite common in embedded systems, and I can totally see how directFB would be good for android. What does it use now? Not X, I know that much. For the apps it wouldn't matter much, once the android framework works, every app can benefit from any performance increases or what not.
And then finally, how does KMS and the kernels' FB driver relate?
That said, I've always had a hard time understanding the difference between X and the framebuffer anyway. You can use both to play mplayer video's, why can't you use the FB for a windowmanager?
P.S. it's been a few years since i tried to read into that stuff
DirectFB uses the framebuffer for displaying stuff. KMS is another FB driver. DirectFB can run on top of it, as Wayland does. X11 also uses KMS for display control. However, you still need special drivers for X11 and DirectFB for full hardware accelleration, which (can) build on top of KMS.
Actually I don't really know, why one needs Wayland as we have DirectFB... Or to put it differently: what does Wayland, what DirectFB can't do today?