Re: [PATCH 12/16] drm/xe: Restructure reuse_vma()

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

On Thu, 23 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Restructure reuse_vma() into a form that doesn't need the plane
> state structs, and rename the result to xe_fb_pin_reuse_vma().
> This will become the new fb_pin parent interface.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

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

> ---
>  drivers/gpu/drm/xe/display/xe_fb_pin.c | 48 ++++++++++++++------------
>  1 file changed, 25 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> index bdd6a4da0997..cd287efded28 100644
> --- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
> +++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> @@ -486,36 +486,31 @@ static void xe_fb_pin_dpt_unpin(struct intel_dpt *dpt,
>  	__xe_unpin_fb_vma(ggtt_vma);
>  }
>  
> -static bool reuse_vma(struct intel_plane_state *new_plane_state,
> -		      const struct intel_plane_state *old_plane_state)
> +static struct i915_vma *
> +xe_fb_pin_reuse_vma(struct i915_vma *old_ggtt_vma,
> +		    struct drm_gem_object *old_obj,
> +		    const struct i915_gtt_view *old_view,
> +		    struct drm_gem_object *new_obj,
> +		    const struct i915_gtt_view *new_view,
> +		    u32 *out_offset)
>  {
> -	struct intel_plane *plane = to_intel_plane(new_plane_state->uapi.plane);
> -	struct i915_vma *vma;
> +	if (old_ggtt_vma && old_obj == new_obj &&
> +	    !memcmp(&old_view, &new_view, sizeof(*new_view))) {
> +		refcount_inc(&old_ggtt_vma->ref);
>  
> -	if (old_plane_state->hw.fb == new_plane_state->hw.fb &&
> -	    !memcmp(&old_plane_state->view.gtt,
> -		    &new_plane_state->view.gtt,
> -		    sizeof(new_plane_state->view.gtt))) {
> -		vma = old_plane_state->ggtt_vma;
> -		goto found;
> +		*out_offset = xe_ggtt_node_addr(old_ggtt_vma->node);
> +
> +		return old_ggtt_vma;
>  	}
>  
> -	return false;
> -
> -found:
> -	refcount_inc(&vma->ref);
> -	new_plane_state->ggtt_vma = vma;
> -
> -	new_plane_state->surf = xe_ggtt_node_addr(new_plane_state->ggtt_vma->node) +
> -		plane->surf_offset(new_plane_state);
> -
> -	return true;
> +	return NULL;
>  }
>  
>  int intel_plane_pin_fb(struct intel_plane_state *new_plane_state,
>  		       const struct intel_plane_state *old_plane_state)
>  {
> -	struct intel_framebuffer *fb = to_intel_framebuffer(new_plane_state->hw.fb);
> +	const struct intel_framebuffer *fb = to_intel_framebuffer(new_plane_state->hw.fb);
> +	const struct intel_framebuffer *old_fb = to_intel_framebuffer(old_plane_state->hw.fb);
>  	struct drm_gem_object *obj = intel_fb_bo(&fb->base);
>  	struct intel_plane *plane = to_intel_plane(new_plane_state->uapi.plane);
>  	struct intel_fb_pin_params pin_params = {
> @@ -529,8 +524,14 @@ int intel_plane_pin_fb(struct intel_plane_state *new_plane_state,
>  	u32 offset;
>  	int ret;
>  
> -	if (reuse_vma(new_plane_state, old_plane_state))
> -		return 0;
> +	ggtt_vma = xe_fb_pin_reuse_vma(old_plane_state->ggtt_vma,
> +				       intel_fb_bo(&old_fb->base),
> +				       &old_plane_state->view.gtt,
> +				       intel_fb_bo(&fb->base),
> +				       &new_plane_state->view.gtt,
> +				       &offset);
> +	if (ggtt_vma)
> +		goto got_vma;
>  
>  	if (!intel_fb_uses_dpt(&fb->base)) {
>  		ret = xe_fb_pin_ggtt_pin(obj, &pin_params,
> @@ -544,6 +545,7 @@ int intel_plane_pin_fb(struct intel_plane_state *new_plane_state,
>  			return ret;
>  	}
>  
> +got_vma:
>  	new_plane_state->dpt_vma = dpt_vma;
>  	new_plane_state->ggtt_vma = ggtt_vma;
>  	new_plane_state->fence_id = fence_id;

-- 
Jani Nikula, Intel