[Intel-gfx] [PATCH 03/43] drm/i915/selftests: Improve switch-to-kernel-context checking

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-03-07 12:40:43)
> 
> On 06/03/2019 14:24, Chris Wilson wrote:
> > We can reduce the switch-to-kernel-context selftest to operate as a loop
> > and so trivially test another state transition (that of idle->busy).
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> > -     err = i915_gem_switch_to_kernel_context(i915);
> > -     if (err)
> > -             return err;
> > +             /* XXX Bonus points for proving we are the kernel context! */
> 
> Before the patch intel_engine_has_kernel_context was used for this, why 
> not any more?

Because in the brave new world, that function doesn't work and is
removed in the next? (next but one?) patch.

I haven't thought of a good replacement yet. It would be nice to be able
to categorically state when the GPU has the kernel context bound, but
the closest I have atm is to be able to only say that when idle we are
in the kernel context (and long may we remain idle!). 
-Chris