[Intel-gfx] [PATCH 8/8] drm/i915: Expose RPCS (SSEU) configuration to userspace

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-08-14 15:40:58)
> +static int
> +i915_gem_context_reconfigure_sseu(struct i915_gem_context *ctx,
> +                                 struct intel_engine_cs *engine,
> +                                 struct intel_sseu sseu)
> +{
> +       struct drm_i915_private *i915 = ctx->i915;
> +       struct i915_request *rq;
> +       struct intel_ring *ring;
> +       int ret;
> +
> +       lockdep_assert_held(&i915->drm.struct_mutex);
> +
> +       /* Submitting requests etc needs the hw awake. */
> +       intel_runtime_pm_get(i915);
> +
> +       i915_retire_requests(i915);
> +
> +       /* Now use the RCS to actually reconfigure. */
> +       engine = i915->engine[RCS];
> +
> +       rq = i915_request_alloc(engine, i915->kernel_context);
> +       if (IS_ERR(rq)) {
> +               ret = PTR_ERR(rq);
> +               goto out_put;
> +       }
> +
> +       ret = engine->emit_rpcs_config(rq, ctx, sseu);
> +       if (ret)
> +               goto out_add;
> +
> +       /* Queue this switch after all other activity */
> +       list_for_each_entry(ring, &i915->gt.active_rings, active_link) {
> +               struct i915_request *prev;
> +
> +               prev = last_request_on_engine(ring->timeline, engine);
> +               if (prev)
> +                       i915_sw_fence_await_sw_fence_gfp(&rq->submit,
> +                                                        &prev->submit,
> +                                                        I915_FENCE_GFP);
> +       }
> +
> +       i915_gem_set_global_barrier(i915, rq);
> +
> +out_add:
> +       i915_request_add(rq);
> +out_put:
> +       intel_runtime_pm_put(i915);
> +
> +       return ret;

Looks like we should be able to hook this up to a selftest to confirm
the modification does land in the target context image, and a SRM to
confirm it loaded.
-Chris