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

[Chris Wilson]

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.
-Chris