Hi daal!
I've tried directfb with chocolate-doom from the repos and it behaves the same as MAME. Using a USB keyboard made no difference - I get the same probs as using the integrated keyboard which is that either directfb spawns a terminal under the window I want to use (which is semi-transparent by default) and that captures keyboard input instead of MAME/DOOM or the keyboard doesn't work at all, depending on what options I feed to DFB.
I've just tried recompiling directfb 1.7.7 using most of the same options you used, most notably using the same input options (minus tslib whch I'm not bothering with yet) but unlike you I didn't disable SDL. Why did you disable SDL when you built directfb?
I built dfb today against the patched SDL package I've posted in the SDL thread as I suspected my probs could've been down to me running a directfb that was compiled against a slightly newer SDL (the one in the repos) but my new dfb package doesn't work any better than the one from the repos despite being built with SDL enabled and only the patched 1.2.14 version of SDL being installed, no SDL2.
If I run `dfbinfo` it shows dfb recognises the Z's keyboard and mouse (the touchscreen). If I run `dfbinput` I get logged out and it opens a new QVGA VT. It's definitely got issues somewhere!
When compiling DirectFB there is no need to include SDL.
The SDL backend on DirectFB makes DirectFB apps run via SDL (mostly used for developing and not what you want).
In theory you could run SDL apps on DirectFB using SDL again and causing a indefinite loop
You only need DirectFB support in SDL to make things work for your purpose.( run SDL apps on DirectFB using FBDEV)
No need for SDL support in DirectFB (hope this makes sense)
So to clarify, SDL is build against DirectFB as a back-end, in your case, not the other way around. Its a bit confusing I know.
I would suggest to build the older DirectFB source I included in the post, then after that, build my SDL source using that DirectFB library and try again.
I did not have these issues back then, and things may have changed with DirectFB newer versions.