fb != directfb.
Also, see this warning in evas readme:
--enable-directfb[=static]
   
   this is the direct fb engine that uses direcftb (http://www.directfb.org) on
   linux to access the framebuffer with (or maybe without) acceleration. for
   people making set-top boxes or just wanting an alternative to X this is
   really good. it may also be useful for embedded devices supported by
   directfb that offer acceleration (otherwise the fb driver will likely be
   faster). as such this engine is in relative disrepair and is not
   maintained. use with great care.
http://trac.enlightenment.org/e/browser/trunk/evas/READMEThe way I read it is that it's for the normal fb, not the directfb backend.