Re: [Intel-gfx] [PATCH v2 4/4] drm/i915: Add function to clear scanout flag for vmas

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 30 May 2023, Jouni Högander <jouni.hogander@intel.com> wrote:
> Currently frontbuffer tracking code is directly iterating over object vmas
> and clearing scanout flags for them. Add function to clear scanout flag for
> vmas and use it from frontbuffer tracking code.
>
> v2: describe function parameter.
>
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>

I don't really have confidence on what the right placement of the
function should be, but it does what it says on the box.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  .../gpu/drm/i915/display/intel_frontbuffer.c  |  8 +-------
>  drivers/gpu/drm/i915/i915_vma.c               | 20 +++++++++++++++++++
>  drivers/gpu/drm/i915/i915_vma.h               |  2 ++
>  3 files changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.c b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> index 41ac65c98720..29ac068b8fa5 100644
> --- a/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> +++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> @@ -226,16 +226,10 @@ static void frontbuffer_release(struct kref *ref)
>  	struct intel_frontbuffer *front =
>  		container_of(ref, typeof(*front), ref);
>  	struct drm_i915_gem_object *obj = front->obj;
> -	struct i915_vma *vma;
>  
>  	drm_WARN_ON(&intel_bo_to_i915(obj)->drm, atomic_read(&front->bits));
>  
> -	spin_lock(&obj->vma.lock);
> -	for_each_ggtt_vma(vma, obj) {
> -		i915_vma_clear_scanout(vma);
> -		vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
> -	}
> -	spin_unlock(&obj->vma.lock);
> +	i915_ggtt_clear_scanout(obj);
>  
>  	i915_gem_object_set_frontbuffer(obj, NULL);
>  	spin_unlock(&intel_bo_to_i915(obj)->display.fb_tracking.lock);
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index c66ff2157f6a..c6be96206ee5 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1629,6 +1629,26 @@ int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>  	return err;
>  }
>  
> +/**
> + * i915_ggtt_clear_scanout - Clear scanout flag for all objects ggtt vmas
> + * @obj: i915 GEM object
> + * This function clears scanout flags for objects ggtt vmas. These flags are set
> + * when object is pinned for display use and this function to clear them all is
> + * targeted to be called by frontbuffer tracking code when the frontbuffer is
> + * about to be released.
> + */
> +void i915_ggtt_clear_scanout(struct drm_i915_gem_object *obj)
> +{
> +	struct i915_vma *vma;
> +
> +	spin_lock(&obj->vma.lock);
> +	for_each_ggtt_vma(vma, obj) {
> +		i915_vma_clear_scanout(vma);
> +		vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
> +	}
> +	spin_unlock(&obj->vma.lock);
> +}
> +
>  static void __vma_close(struct i915_vma *vma, struct intel_gt *gt)
>  {
>  	/*
> diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> index 9a9729205d5b..eaa310864370 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -435,6 +435,8 @@ static inline void i915_vma_clear_scanout(struct i915_vma *vma)
>  	clear_bit(I915_VMA_SCANOUT_BIT, __i915_vma_flags(vma));
>  }
>  
> +void i915_ggtt_clear_scanout(struct drm_i915_gem_object *obj);
> +
>  #define for_each_until(cond) if (cond) break; else
>  
>  /**

-- 
Jani Nikula, Intel Open Source Graphics Center