[Intel-gfx] [PATCH 1/3] drm/i915/execlists: Force write serialisation into context image vs execution

[Chris Wilson]

Quoting Chris Wilson (2018-11-08 12:11:05)
> Quoting Mika Kuoppala (2018-11-08 12:00:39)
> > Chris Wilson <chris at chris-wilson.co.uk> writes:
> > 
> > > Ensure that the writes into the context image are completed prior to the
> > > register mmio to trigger execution. Although previously we were assured
> > > by the SDM that all writes are flushed before an uncached memory
> > > transaction (our mmio write to submit the context to HW for execution),
> > > we have empirical evidence to believe that this is not actually the
> > > case.
> > >
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108656
> > 
> > I would have marked this also as References.
> 
> I'm confident in my local results indicating some success here, albeit
> in not exactly the same quick death, but still out-of-bounds execution.

For the record, bsw just hung after close to a day, with the same out of
bounds execution (BBADDR after the batch).
/o\
-Chris