TTM and AGP conflicts

[James Simmons]

Hi!

	I updated the openchrome tree and while testing on the AGP system 
discovered some interesting problems with the new TTM changes. The 
problems center around the ttm_tt_[un]populate which I modeled after the 
radeon and nouveau driver. 
	First problem I noticed was on a AGP system that my ttm_tt_populate
function would oops. Tracking it down I found the problem was the 
ttm_agp_tt_create calls ttm_tt_init instead of ttm_dma_tt_init so once my 
ttm_tt_populate function would attempt to touch the dma_address it would 
oops. The second issue is the assumption of the cast for struct ttm_tt in
both the populate and unpopulate function. For the AGP case the proper 
case would be to ttm_agp_backend.
	At this point my assumption is the ttm_bo_move function has to be
rewritten to handle the AGP case to avoid calling ttm_tt_bind and in all 
cases ttm_tt_bind needs to be avoided. Looking at the radeon and nouveau 
drivers I don't see that testing happening. Am I just missing something?