[Intel-gfx] [PATCH] drm/i915: Revoke partial fences when installing on the scanout

[Chris Wilson]

On Thu, Dec 22, 2016 at 01:52:24PM +0000, Chris Wilson wrote:
> In commit 50349247ea80 ("drm/i915: Drop ORIGIN_GTT for untracked GTT
> writes") partial mmaps were updated to indicate that writes through them
> were not tracked automatically by the hardware and that the expected
> subsequent manual invalidations by the application (on calling dirtyfb at
> the end of the frame) take over from the hardware tracking. However, not
> all applications actually call dirtyfb on the scanout after they dirty it
> and so those writes through partial GTT mmaps are not being tracked and
> triggering FBC updates.
> 
> Fixes: a61007a83a46 ("drm/i915: Fix partial GGTT faulting")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> Cc: "Zanoni, Paulo R" <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c        | 25 ++++++++++++++++++++-----
>  drivers/gpu/drm/i915/i915_gem_object.h |  2 ++
>  drivers/gpu/drm/i915/intel_display.c   | 10 +++++++++-
>  3 files changed, 31 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f379c5484a84..d51c9b209837 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1882,11 +1882,6 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
>  			compute_partial_view(obj, area,
>  					     page_offset, MIN_CHUNK_PAGES);
>  
> -		/* Userspace is now writing through an untracked VMA, abandon
> -		 * all hope that the hardware is able to track future writes.
> -		 */
> -		obj->frontbuffer_ggtt_origin = ORIGIN_CPU;
> -
>  		vma = i915_gem_object_ggtt_pin(obj, &view, 0, 0, PIN_MAPPABLE);
>  	}
>  	if (IS_ERR(vma)) {
> @@ -2015,6 +2010,26 @@ i915_gem_release_mmap(struct drm_i915_gem_object *obj)
>  	intel_runtime_pm_put(i915);
>  }
>  
> +bool i915_gem_object_has_partial_fences(struct drm_i915_gem_object *obj)
> +{
> +	struct i915_vma *vma;
> +
> +	lockdep_assert_held(&obj->base.dev->struct_mutex);
> +
> +	list_for_each_entry(vma, &obj->vma_list, obj_link) {
> +		if (!i915_vma_is_ggtt(vma))
> +			break;
> +
> +		if (vma->ggtt_view.type != I915_GGTT_VIEW_NORMAL)

if (vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL)

> +			continue;

Ofc.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre