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Commit d45a4dd5 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Drop wmb() inside pread_gtt 



Inside pread, we only ever read from the GTT so the serialising wmb()
instructions around the GGTT PTE updates are pointless.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190718145407.21352-1-chris@chris-wilson.co.uk
parent bffb31f7

drivers/gpu/drm/i915/i915_gem.c

+0 −3
Original line number Diff line number Diff line
@@ -395,11 +395,9 @@ i915_gem_gtt_pread(struct drm_i915_gem_object *obj, 
		unsigned page_length = PAGE_SIZE - page_offset;

		page_length = remain < page_length ? remain : page_length;

		if (node.allocated) {

			wmb();

			ggtt->vm.insert_page(&ggtt->vm,

					     i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT),

					     node.start, I915_CACHE_NONE, 0);

			wmb();

		} else {

			page_base += offset & PAGE_MASK;

		}
@@ -419,7 +417,6 @@ i915_gem_gtt_pread(struct drm_i915_gem_object *obj, 
out_unpin:

	mutex_lock(&i915->drm.struct_mutex);

	if (node.allocated) {

		wmb();

		ggtt->vm.clear_range(&ggtt->vm, node.start, node.size);

		remove_mappable_node(&node);

	} else {