Commit 18034584 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Fallback to single page pwrite/pread if unable to release fence 



If we cannot release the fence (for example if someone is inexplicably
trying to write into a tiled framebuffer that is currently pinned to the
display! *cough* kms_frontbuffer_tracking *cough*) fallback to using the
page-by-page pwrite/pread interface, rather than fail the syscall
entirely.

Since this is triggerable by the user (along pwrite) we have to remove
the WARN_ON(fence->pin_count).

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-6-chris@chris-wilson.co.uk
parent d243ad82

drivers/gpu/drm/i915/i915_gem.c

+18 −12
Original line number Diff line number Diff line
@@ -754,6 +754,15 @@ i915_gem_gtt_pread(struct drm_device *dev, 
	int ret;



	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, PIN_MAPPABLE);

	if (!IS_ERR(vma)) {

		node.start = i915_ggtt_offset(vma);

		node.allocated = false;

		ret = i915_gem_object_put_fence(obj);

		if (ret) {

			i915_vma_unpin(vma);

			vma = ERR_PTR(ret);

		}

	}

	if (IS_ERR(vma)) {

		ret = insert_mappable_node(dev_priv, &node, PAGE_SIZE);

		if (ret)
@@ -766,12 +775,6 @@ i915_gem_gtt_pread(struct drm_device *dev, 
		}



		i915_gem_object_pin_pages(obj);

	} else {

		node.start = i915_ggtt_offset(vma);

		node.allocated = false;

		ret = i915_gem_object_put_fence(obj);

		if (ret)

			goto out_unpin;

	}



	ret = i915_gem_object_set_to_gtt_domain(obj, false);
@@ -1058,6 +1061,15 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_private *i915, 


	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,

				       PIN_MAPPABLE | PIN_NONBLOCK);

	if (!IS_ERR(vma)) {

		node.start = i915_ggtt_offset(vma);

		node.allocated = false;

		ret = i915_gem_object_put_fence(obj);

		if (ret) {

			i915_vma_unpin(vma);

			vma = ERR_PTR(ret);

		}

	}

	if (IS_ERR(vma)) {

		ret = insert_mappable_node(i915, &node, PAGE_SIZE);

		if (ret)
@@ -1070,12 +1082,6 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_private *i915, 
		}



		i915_gem_object_pin_pages(obj);

	} else {

		node.start = i915_ggtt_offset(vma);

		node.allocated = false;

		ret = i915_gem_object_put_fence(obj);

		if (ret)

			goto out_unpin;

	}



	ret = i915_gem_object_set_to_gtt_domain(obj, true);

drivers/gpu/drm/i915/i915_gem_fence.c

+1 −1
Original line number Diff line number Diff line
@@ -298,7 +298,7 @@ i915_gem_object_put_fence(struct drm_i915_gem_object *obj) 


	fence = &dev_priv->fence_regs[obj->fence_reg];



	if (WARN_ON(fence->pin_count))

	if (fence->pin_count)

		return -EBUSY;



	i915_gem_object_fence_lost(obj);

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