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Commit def0c5f6 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
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drm/i915: Map the ringbuffer using WB on LLC machines 



If we have llc coherency, we can write directly into the ringbuffer
using ordinary cached writes rather than forcing WC access.

v2: An important consequence is that we can forgo the mappable request
for WB ringbuffers, allowing for many more simultaneous contexts.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 1f9a99e0

drivers/gpu/drm/i915/intel_ringbuffer.c

+56 −14
Original line number Diff line number Diff line
@@ -2002,11 +2002,35 @@ static int init_phys_status_page(struct intel_engine_cs *ring) 


void intel_unpin_ringbuffer_obj(struct intel_ringbuffer *ringbuf)

{

	if (HAS_LLC(ringbuf->obj->base.dev) && !ringbuf->obj->stolen)

		vunmap(ringbuf->virtual_start);

	else

		iounmap(ringbuf->virtual_start);

	ringbuf->virtual_start = NULL;

	i915_gem_object_ggtt_unpin(ringbuf->obj);

}



static u32 *vmap_obj(struct drm_i915_gem_object *obj)

{

	struct sg_page_iter sg_iter;

	struct page **pages;

	void *addr;

	int i;



	pages = drm_malloc_ab(obj->base.size >> PAGE_SHIFT, sizeof(*pages));

	if (pages == NULL)

		return NULL;



	i = 0;

	for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0)

		pages[i++] = sg_page_iter_page(&sg_iter);



	addr = vmap(pages, i, 0, PAGE_KERNEL);

	drm_free_large(pages);



	return addr;

}



int intel_pin_and_map_ringbuffer_obj(struct drm_device *dev,

				     struct intel_ringbuffer *ringbuf)

{
@@ -2014,6 +2038,23 @@ int intel_pin_and_map_ringbuffer_obj(struct drm_device *dev, 
	struct drm_i915_gem_object *obj = ringbuf->obj;

	int ret;



	if (HAS_LLC(dev_priv) && !obj->stolen) {

		ret = i915_gem_obj_ggtt_pin(obj, PAGE_SIZE, 0);

		if (ret)

			return ret;



		ret = i915_gem_object_set_to_cpu_domain(obj, true);

		if (ret) {

			i915_gem_object_ggtt_unpin(obj);

			return ret;

		}



		ringbuf->virtual_start = vmap_obj(obj);

		if (ringbuf->virtual_start == NULL) {

			i915_gem_object_ggtt_unpin(obj);

			return -ENOMEM;

		}

	} else {

		ret = i915_gem_obj_ggtt_pin(obj, PAGE_SIZE, PIN_MAPPABLE);

		if (ret)

			return ret;
@@ -2030,6 +2071,7 @@ int intel_pin_and_map_ringbuffer_obj(struct drm_device *dev, 
			i915_gem_object_ggtt_unpin(obj);

			return -EINVAL;

		}

	}



	return 0;

}