[Intel-gfx] [PATCH 04/20] drm/i915: Mark the addition of the initial-breadcrumb in the request

[Chris Wilson]

Quoting Mika Kuoppala (2020-05-11 12:21:55)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > The initial-breadcrumb is used to mark the end of the awaiting and the
> > beginning of the user payload. We verify that we do not start the user
> > payload before all signaler are completed, checking our semaphore setup
> > by looking for the initial breadcrumb being written too early. We also
> > want to ensure that we do not add semaphore waits after we have already
> > closed the semaphore section, an issue for later deferred waits.
> >
> 
> I see that you go from timeline property to a per request property.
> But the last sentence in this commit message escapes me. Do we need
> this for proxy fence waiting of is this patch just for enhancing
> the assertion/gem_bug_on resolution on semaphore boundaries?

The immediate improvement is for tidying up the assertion. It opens the
way for out-of-order awaits.
-Chris