[Intel-gfx] [PATCH 9/9] drm/i915/gen12: Flush LLC

[Chris Wilson]

Quoting Mika Kuoppala (2020-04-30 16:47:35)
> Request boundary is a global observation point for
> all operations. Thus flush the LLC too.
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

This one always concerned me for being unbounded in cost: flush all the
LLC lines that might be framebuffer.

We don't mix scanout and LLC, so we've never felt concerned to enable
this flush. [It's definitely not gen12+!]

I would not enable this bit without good cause and verification it
doesn't cost anything for normal render paths.

Still we need to record this bit. For example, I might
suggest it is coupled into the flush-display path directly.
-Chris