[Intel-gfx] [PATCH 2/5] drm/i915/perf: allow holding preemption on filtered ctx

[Chris Wilson]

Quoting Lionel Landwerlin (2019-05-21 15:08:52)
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index f263a8374273..2ad95977f7a8 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -2085,7 +2085,7 @@ static int gen9_emit_bb_start(struct i915_request *rq,
>         if (IS_ERR(cs))
>                 return PTR_ERR(cs);
>  
> -       *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
> +       *cs++ = MI_ARB_ON_OFF | rq->hw_context->arb_enable;

My prediction is that this will result in this context being reset due
to preemption timeouts and the context under profile being banned. Note
that preemption timeouts will be the primary means for hang detection
for endless batches.
-Chris