[Intel-gfx] [RFC v3] drm/i915: Eliminate devid sprinkle

[Chris Wilson]

Quoting Jani Nikula (2018-02-26 14:00:37)
> On Thu, 22 Feb 2018, Tvrtko Ursulin <tursulin at ursulin.net> wrote:
> > From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >
> > Introduce subplatform mask to eliminate throughout the code devid checking
> > sprinkle, mostly courtesy of IS_*_UL[TX] macros.
> >
> > Subplatform mask initialization is moved either to static tables (Ironlake
> > M) or runtime device info init (Pineview, Haswell, Broadwell, Skylake,
> > Kabylake, Coffeelake and Cannonlake).
> 
> I thought Chris had the goal of separating runtime and static init, and
> I very much agreed with that idea. Throw away the mkwrite stuff. This
> patch seems to be at odds with that goal by tying a runtime init into
> the same mask with statically initialized platform mask.

Yes.

In the extreme version of single platform LTO, we would bake one
device-info stanza for every subplatform. That may be a little overkill
(or rather too complicated for the user to know and too fine-grained to
be useful). So the middle ground is that we have subplatform in the
runtime_info, and the compiler has to do two loads. We can still benefit
from using BIT() though.
-Chris