Re: [PATCH 1/3] drm/i915: Only perform set-to-gtt domain for objects bound to the global gtt

[Daniel Vetter <daniel@ffwll.ch>]

On Sat, Aug 09, 2014 at 05:37:22PM +0100, Chris Wilson wrote:
> If an object is not bound into the global GTT, then it cannot be
> accessed via the GTT. This restores the original code that was muddled
> by ppGTT. In the process, we remove a WARN that had long outlived its
> usefulness and was simply being coded around instead.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 22 +++++-----------------
>  1 file changed, 5 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 80b807b724a6..99250d27668d 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3594,11 +3594,12 @@ int
>  i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
>  {
>  	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> +	struct i915_vma *vma = i915_gem_obj_to_ggtt(obj);
>  	uint32_t old_write_domain, old_read_domains;
>  	int ret;
>  
>  	/* Not valid to be called on unbound objects. */
> -	if (!i915_gem_obj_bound_any(obj))
> +	if (vma == NULL)
>  		return -EINVAL;
>  
>  	if (obj->base.write_domain == I915_GEM_DOMAIN_GTT)
> @@ -3640,13 +3641,9 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
>  					    old_write_domain);
>  
>  	/* And bump the LRU for this access */
> -	if (i915_gem_object_is_inactive(obj)) {
> -		struct i915_vma *vma = i915_gem_obj_to_ggtt(obj);
> -		if (vma)
> -			list_move_tail(&vma->mm_list,
> -				       &dev_priv->gtt.base.inactive_list);
> -
> -	}
> +	if (i915_gem_object_is_inactive(obj))

Ben will put a few more needles into his danvet voodoo doll, but I guess
this here is a fairly clear indicator that tracking the active bit on the
object instead of the vma wasn't an awesome idea ...

Anyway, patch looks good, merged.
-Daniel

> +		list_move_tail(&vma->mm_list,
> +			       &dev_priv->gtt.base.inactive_list);
>  
>  	return 0;
>  }
> @@ -3810,9 +3807,6 @@ static bool is_pin_display(struct drm_i915_gem_object *obj)
>  {
>  	struct i915_vma *vma;
>  
> -	if (list_empty(&obj->vma_list))
> -		return false;
> -
>  	vma = i915_gem_obj_to_ggtt(obj);
>  	if (!vma)
>  		return false;
> @@ -5255,12 +5249,6 @@ struct i915_vma *i915_gem_obj_to_ggtt(struct drm_i915_gem_object *obj)
>  {
>  	struct i915_vma *vma;
>  
> -	/* This WARN has probably outlived its usefulness (callers already
> -	 * WARN if they don't find the GGTT vma they expect). When removing,
> -	 * remember to remove the pre-check in is_pin_display() as well */
> -	if (WARN_ON(list_empty(&obj->vma_list)))
> -		return NULL;
> -
>  	vma = list_first_entry(&obj->vma_list, typeof(*vma), vma_link);
>  	if (vma->vm != obj_to_ggtt(obj))
>  		return NULL;
> -- 
> 2.1.0.rc1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch