[Intel-gfx] [PATCH v6] drm/i915: Emit to ringbuffer directly

[Chris Wilson]

On Wed, Feb 08, 2017 at 06:04:20PM +0000, Tvrtko Ursulin wrote:
> @@ -868,10 +869,11 @@ void __i915_add_request(struct drm_i915_gem_request *request, bool flush_caches)
>  	 * GPU processing the request, we never over-estimate the
>  	 * position of the ring's HEAD.
>  	 */
> -	err = intel_ring_begin(request, engine->emit_breadcrumb_sz);
> -	GEM_BUG_ON(err);
> -	request->postfix = ring->tail;
> -	ring->tail += engine->emit_breadcrumb_sz * sizeof(u32);
> +	out = intel_ring_begin(request, engine->emit_breadcrumb_sz);
> +	GEM_BUG_ON(IS_ERR(out));
> +	GEM_BUG_ON(engine->emit_breadcrumb_sz * sizeof(u32) > ring->tail);
> +	request->postfix = ring->tail -
> +			   engine->emit_breadcrumb_sz * sizeof(u32);

request->postfix = intel_ring_offset(req, out); ?

-- 
Chris Wilson, Intel Open Source Technology Centre