[RFC] ttm merge ttm_backend & ttm_t V2

[j.glisse@gmail.com]

Hi,

So attached is last batch of patch, i split the ttm put page
fix and i fixed a bug in the pages alloc when clear flags
wasn't set. I tested them on a bunch of radeon and everythings
seems fine (several gl app, firefox, compositor ...). I will
do more testing on agp and nouveau tomorrow.

The last patch add callback for populating and unpopulating
(better name if any welcome) a ttm_tt. Allowing the driver
to choose btw different choice, idea is that Konrad dma
allocator would provide helper function the driver can
call.

I choosed to allocate all page at once because ttm_tt object
are meant to be bind and thus to be fully populated in their
lifetime (vmwgfx might be different in this regard). It
simplify code in several place. I didn't see any performances
impact in the few gl benchmark i ran.

Konrad so i am planning on rebasing the last 4 patch of your
patchset on top of that. They will likely shrink in size a
bit.

Cheers,
Jerome Glisse