[Intel-gfx] [PATCH 10/29] drm/i915: Introduce context->enter() and context->exit()

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-04-10 12:06:49)
> 
> On 10/04/2019 11:13, Chris Wilson wrote:
> > Quoting Tvrtko Ursulin (2019-04-10 11:05:13)
> >> And some lockdep_assert_held in all three?
> > 
> > Read on :(
> > 
> > The plan is for intel_context_enter/_exit to be under the
> > timeline->mutex, but that isn't realised for about another 30 patches.
> > 
> > mark_active has special protection because it gets used from the
> > serialised portion of intel_engine_park.
> 
> Ok, but bug on for zero active_count makes sense right? Maybe even 
> intel_context_pin_active to signify that it can only act on an already 
> active context?

It get's called on the kernel_context with ce->active_count==0 and not
even holding the mutex from inside the wakeref handling code. (On no,
I've invented a new BKL --- well a parking brake.)
-Chris