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: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190718145407.21352-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2019-07-18 15:54:04 +01:00
parent bffb31f73b
commit d45a4dd527

View file

@ -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 {