[Xorg] Xfbdev acceleration without offscreen pixmaps?

[Michael Frey]

After reading the code in kaa.c I noticed that a video driver who 
supplies acceleration code is only called if there is available 
offscreen pixmaps other wise it falls through and uses fbdev.

for example: in kaaFillRegionSolid
     if (pScreenPriv->enabled &&
	(pPixmap = kaaGetOffscreenPixmap (pDrawable, &xoff, &yoff)) &&
	(*pKaaScr->info->PrepareSolid) (pPixmap, GXcopy, FB_ALLONES, pixel))

I have a video card that only has enough memory for the on screen frame 
buffer but It has a 2DBLT engine.  I have code that I used in the 
XFree86 tree with kdrive that works great and I want to move to the new 
kdrive from freedesktop.  Can someone tell me if it is possible to use 
acceleration routines without using offscreen pixamps?

Thanks in advance,
Michael