Questions about XAA

[cckuo]

Dear X friends:
I got some questions about behaviors about XAA. 
Below are the log messages I excerpted from the log file as I attached:
(II) VIA(0): Using XFree86 Acceleration Architecture (XAA)
	8x8 color pattern filled rectangles    
	Screen to Screen color expansion
	Image Writes
	Offscreen Pixmaps
****	Setting up tile and stipple cache:
		6 128x128 slots
		32 8x8 color pattern slots
The messages below the **** was printed from XAAInitPixmapCache in
xaaPCache.c by clipping the areas passed from FBManager. And here comes my
question:
1) How does XAA determine the size and # of tile and stipple cache for a
given graphics controller?
  2)  Are there any graphic controllers with fixed features, etc., built
directly into XAA?
  3)  Is there anyway to specifically set the slot sizes and # of slots for
a given graphics controller? I mean is there options I can set in my
configure file or the only way I can do is to modify the source code of
frame buffer manager?

If you have the same experience and got any ideas about this, please let me
know.
Appreciate for your help in advance.
Sincerely Yours,
cckuo