[Intel-gfx] [RFCv5 2/2] drm/i915: Introduce private PAT management

[Chris Wilson]

Quoting Zhi Wang (2017-08-29 09:00:51)
> The private PAT management is to support PPAT entry manipulation. Two
> APIs are introduced for dynamically managing PPAT entries: intel_ppat_get
> and intel_ppat_put.
> 
> intel_ppat_get will search for an existing PPAT entry which perfectly
> matches the required PPAT value. If not, it will try to allocate or
> return a partially matched PPAT entry if there is any available PPAT
> indexes or not.
> 
> intel_ppat_put will put back the PPAT entry which comes from
> intel_ppat_get. If it's dynamically allocated, the reference count will
> be decreased. If the reference count turns into zero, the PPAT index is
> freed again.
> 
> Besides, another two callbacks are introduced to support the private PAT
> management framework. One is ppat->update(), which writes the PPAT
> configurations in ppat->entries into HW. Another one is ppat->match, which
> will return a score to show how two PPAT values match with each other.

Oh and since you are exporting an interface, I bet you would appreciate
it if we had some unittests in selftests/ ;)
-Chris