[Intel-gfx] [PATCH] drm/i915/perf: reintroduce wait on OA configuration completion

[Chris Wilson]

Quoting Chris Wilson (2020-02-27 17:04:42)
> Quoting Lionel Landwerlin (2020-02-27 12:43:56)
> > We still need to wait for the initial OA configuration to happen
> > before we enable OA report writes to the OA buffer.
> 
> I can confirm this fixes the hang Lionel reported on Skylake [still odd
> that we can only get this to be an issue on skl]. However, Lionel
> mentioned that we should be more careful and ensure the emit_oa_config()
> request is scheduled last. We're currently looking at different ways we
> can do that.

Fwiw, this patch works and fixes the problem. I prefer not adding
a single use temporary to i915_perf_stream, but I leave that choice to
Lionel.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris