[Mesa-dev] [PATCH 12/12] i965: Prefer to use the GPU copy if we need to stall for reads

[Chris Wilson]

Quoting Chris Wilson (2017-08-04 21:01:16)
> If we need to stall to read the bo, ask the GPU to copy it into the CPU
> cache whilst we wait.

This is more food for thought, as I think we need to change the priority
ladder first. Aiui, miptree_map is the last resort so we don't want
needless complexity for cases we can identify and handle before hitting
this fallback. (I have an untidy series to blorpify read/drawpixels
get/subteximage.)
-Chris