[Intel-gfx] [PATCH 3/8] drm/i915/ringbuffer: Clear semaphore sync registers on ring init

[Chris Wilson]

Quoting Mika Kuoppala (2018-12-03 12:05:25)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > Ensure that the sync registers are cleared every time we restart the
> > ring to avoid stale values from creeping in from random neutrinos.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  drivers/gpu/drm/i915/intel_ringbuffer.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > index 992889f9e0ff..81b10d85b738 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -529,6 +529,13 @@ static int init_ring_common(struct intel_engine_cs *engine)
> >  
> >       intel_engine_reset_breadcrumbs(engine);
> >  
> > +     if (HAS_LEGACY_SEMAPHORES(engine->i915)) {
> > +             I915_WRITE(RING_SYNC_0(engine->mmio_base), 0);
> > +             I915_WRITE(RING_SYNC_1(engine->mmio_base), 0);
> > +             if (HAS_VEBOX(dev_priv))
> 
> Minor nitpick: mixed i915 and dev_priv usage. 

I don't think you are ready yet for i915_write32(i915, reg, value). :-p
-Chris