[Intel-gfx] [PATCH 8/8] drm/i915: Improve GuC request coalescing

[Chris Wilson]

Quoting Mika Kuoppala (2017-09-20 15:37:05)
> -static void i915_guc_submit(struct intel_engine_cs *engine)
> +static void i915_guc_submit(struct intel_engine_cs *engine,
> +                           const unsigned int first)
>  {
>         struct drm_i915_private *dev_priv = engine->i915;
>         struct intel_guc *guc = &dev_priv->guc;
> @@ -498,7 +500,7 @@ static void i915_guc_submit(struct intel_engine_cs *engine)
>         const unsigned int engine_id = engine->id;
>         unsigned int n;
>  
> -       for (n = 0; n < execlist_active_ports(el); n++) {
> +       for (n = first; n < execlist_active_ports(el); n++) {
>                 struct execlist_port *port;
>                 struct drm_i915_gem_request *rq;
>                 unsigned int count;
> @@ -506,21 +508,22 @@ static void i915_guc_submit(struct intel_engine_cs *engine)
>                 port = execlist_port_index(el, n);
>  
>                 rq = port_unpack(port, &count);
> -               if (rq && count == 0) {
> -                       port_set(port, port_pack(rq, ++count));
> +               GEM_BUG_ON(!rq);
> +               GEM_BUG_ON(count);
>  
> -                       if (i915_vma_is_map_and_fenceable(rq->ring->vma))
> -                               POSTING_READ_FW(GUC_STATUS);
> +               port_set(port, port_pack(rq, ++count));

Ok, with this method we don't need count anymore. Seems sensible.
-Chris