directfb 例子在sdl下错误！！

beaver22

出现：
(!) Core/SurfBuffer: Buffer allocation failed!
    --> Not supported!
(!) Core/LayerRegion: Could not lock region surface for SetRegion()!
    --> Not supported!
(!) Core/LayerRegion: realize_region() in dfb_layer_region_flip_update() failed!
    --> Not supported!

用dfbinfo查看：
DirectFB 1.4.0 |~~~~~~~~~~~~~~~~~~~~~~~~~~
        (c) 2001-2009  The world wide DirectFB Open Source Community
        (c) 2000-2004  Convergence (integrated media) GmbH
      ----------------------------------------------------------------
(*) DirectFB/Core: Single Application Core. (2009-07-07 08:18)
(*) Direct/Thread: Started 'SDL Input' (2683) [INPUT OTHER/OTHER 0/0] <10485760>...
(*) DirectFB/Input: SDL Input 0.1 (Denis Oliver Kropp)
(*) DirectFB/Genefx: MMX detected and enabled
(*) DirectFB/Graphics: SDL Graphics 0.1 (directfb.org)
(*) Direct/Thread: Started 'Screen Update' (2684) [OUTPUT OTHER/OTHER 0/0] <10485760>...
(*) DirectFB/Core/WM: Default 0.3 (directfb.org)
(!) Core/SurfBuffer: Buffer allocation failed!
    --> Not supported!
(!) Core/LayerRegion: Could not lock region surface for SetRegion()!
    --> Not supported!
(!) Core/LayerRegion: realize_region() in dfb_layer_region_flip_update() failed!
    --> Not supported!
Screen (00) SDL Primary Screen              (primary screen)
   Caps:

     Layer (00) SDL Primary Layer               (primary layer)
        Type:    GRAPHICS
        Caps:    SURFACE

Input (00) SDL Input                       (primary keyboard)
   Type: KEYBOARD MOUSE JOYSTICK
   Caps: KEYS AXES BUTTONS
   Min. Keycode: -1
   Max. Keycode: -1
   Max. Axis: 0
   Max. Button: 0