Yup the frame buffers are memory mapped, at least on all the Sun2 and Sun3
hardware I used to play with back when those machines were *The Thing*.
We used to have lots of fun just filling the memory space with random 
patterns,
either from the monitor ROM command line, or from a  booted kernel, using
a debugger.

But DMA controllers usually have a mode where you can program up 
memory-to-memory
transfers, and this can be used quite effectively to quickly update a 
screen from a prepared
buffer in main RAM. I've done this with custom 68k hardware, but not 
actually on Sun
h/w, so can't give any useful details.

Have fun,
Rick



der Mouse wrote:

>[quoting order normalized -dM]
>  
>
>>>>the cg8 doesn't use DMA ????
>>>>ummm... what does it use ?
>>>>        
>>>>
>>>For what?  What does the cg8 do that you'd think it would have any
>>>use for DMA for?
>>>      
>>>
>>Do any of the framebuffers use DMA ?
>>    
>>
>
>As far as I know they don't.  I have seen things which make me suspect
>that among the undocumented bits of some of them lurk a DMA engine or
>two, but as far as I know the bits remain undocumented and thus unused.
>
>Pity, too, because it would make sense to be able to DMA stuff (either
>video RAM contents or for the more sophisticated boards higher-level
>stuff like drawing operations) from host memory to the framebuffer.
>
>/~\ The ASCII				der Mouse
>\ / Ribbon Campaign
> X  Against HTML	       mouse@rodents.montreal.qc.ca
>/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B
>
>  
>