some half-baked ttm ideas

[Dave Airlie]

On Wed, 16 Sep 2020 at 14:19, Dave Airlie <airlied at gmail.com> wrote:
>
> On Wed, 16 Sep 2020 at 00:12, Christian König
> <ckoenig.leichtzumerken at gmail.com> wrote:
> >
> > Hi Dave,
> >
> > I think we should just completely nuke ttm_tt_bind() and ttm_tt_unbind()
> > and all of that.
> >
> > Drivers can to this from their move_notify() callback now instead.
>
> Good plan, I've put a bunch of rework into the same branch,
>
> https://github.com/airlied/linux/commits/ttm-half-baked-ideas
>
> but I've fried my brain a bit, I'm having trouble reconciling move
> notify and unbinding in the right places, I feel like I'm circling
> around the answer but haven't hit it yet.

drm/ttm: add unbind to move notify paths.

In that tree is incorrect and I think where things fall apart, since
if we are moving TTM to VRAM that will unbind the TTM object from the
GTT at move notify time before the move has executed.

I'm feeling a move_complete_notify might be an idea, but I'm wondering
if it's a bad idea.

Dave.