[Nouveau] [PATCH] drm/ttm: Fix race condition in ttm_bo_delayed_delete

[Luca Barbieri]

> The card also keeps some internal FIFO caches, so it seems to me that
> getting that safe of races and efficient at the same time could be a bit
> non-trivial.

Are they flushable?
It seems this *might* do the job:
if (!pfifo->cache_flush(dev))
return;
pfifo->reassign(dev, false);
pfifo->cache_flush(dev);
pfifo->cache_pull(dev, false);


pfifo->cache_pull(dev, true);
pfifo->reassign(dev, true);