Re: [PATCH 06/16] drm/i915: Introduce i915_fb_pin_ggtt_(un)pin()

[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>
>
> Extract the inner DPT parts of intel_plane_(un)pin() into the
> i915_fb_pin_ggtt_(un)pin(). These will become part of 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/i915/i915_fb_pin.c | 68 +++++++++++++++++++-----------
>  1 file changed, 44 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
> index 0019f570d843..e14d2c1fb81f 100644
> --- a/drivers/gpu/drm/i915/i915_fb_pin.c
> +++ b/drivers/gpu/drm/i915/i915_fb_pin.c
> @@ -257,6 +257,41 @@ intel_plane_fb_vtd_guard(const struct intel_plane_state *plane_state)
>  				       plane_state->hw.rotation);
>  }
>  
> +static int i915_fb_pin_ggtt_pin(struct drm_gem_object *obj,
> +				const struct intel_fb_pin_params *pin_params,
> +				struct i915_vma **out_ggtt_vma,
> +				u32 *out_offset,
> +				int *out_fence_id)
> +{
> +	struct i915_vma *ggtt_vma;
> +
> +	ggtt_vma = intel_fb_pin_to_ggtt(obj, pin_params, out_fence_id);
> +	if (IS_ERR(ggtt_vma))
> +		return PTR_ERR(ggtt_vma);
> +
> +	*out_ggtt_vma = ggtt_vma;
> +
> +	/*
> +	 * Pre-populate the dma address before we enter the vblank
> +	 * evade critical section as i915_gem_object_get_dma_address()
> +	 * will trigger might_sleep() even if it won't actually sleep,
> +	 * which is the case when the fb has already been pinned.
> +	 */
> +	if (pin_params->needs_physical)
> +		*out_offset = i915_gem_object_get_dma_address(to_intel_bo(obj), 0);
> +	else
> +		*out_offset = i915_ggtt_offset(ggtt_vma);
> +
> +	return 0;
> +}
> +
> +static void i915_fb_pin_ggtt_unpin(struct i915_vma *ggtt_vma,
> +				   int fence_id)
> +{
> +	if (ggtt_vma)
> +		intel_fb_unpin_vma(ggtt_vma, fence_id);
> +}
> +
>  static int i915_fb_pin_dpt_pin(struct drm_gem_object *obj, struct intel_dpt *dpt,
>  			       const struct intel_fb_pin_params *pin_params,
>  			       struct i915_vma **out_dpt_vma,
> @@ -325,24 +360,11 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state,
>  			.needs_fence = intel_plane_needs_fence(display),
>  		};
>  
> -		ggtt_vma = intel_fb_pin_to_ggtt(intel_fb_bo(&fb->base), &pin_params,
> -						intel_plane_uses_fence(plane_state) ? &fence_id : NULL);
> -		if (IS_ERR(ggtt_vma))
> -			return PTR_ERR(ggtt_vma);
> -
> -		/*
> -		 * Pre-populate the dma address before we enter the vblank
> -		 * evade critical section as i915_gem_object_get_dma_address()
> -		 * will trigger might_sleep() even if it won't actually sleep,
> -		 * which is the case when the fb has already been pinned.
> -		 */
> -		if (intel_plane_needs_physical(plane)) {
> -			struct drm_i915_gem_object *obj = to_intel_bo(intel_fb_bo(&fb->base));
> -
> -			offset = i915_gem_object_get_dma_address(obj, 0);
> -		} else {
> -			offset = i915_ggtt_offset(ggtt_vma);
> -		}
> +		ret = i915_fb_pin_ggtt_pin(intel_fb_bo(&fb->base),
> +					   &pin_params, &ggtt_vma, &offset,
> +					   intel_plane_uses_fence(plane_state) ? &fence_id : NULL);
> +		if (ret)
> +			return ret;
>  	} else {
>  		struct intel_fb_pin_params pin_params = {
>  			.view = &plane_state->view.gtt,
> @@ -371,13 +393,11 @@ void intel_plane_unpin_fb(struct intel_plane_state *old_plane_state)
>  		to_intel_framebuffer(old_plane_state->hw.fb);
>  
>  	if (!intel_fb_uses_dpt(&fb->base)) {
> -		struct i915_vma *vma;
> +		i915_fb_pin_ggtt_unpin(old_plane_state->ggtt_vma,
> +				       old_plane_state->fence_id);
>  
> -		vma = fetch_and_zero(&old_plane_state->ggtt_vma);
> -		if (vma) {
> -			intel_fb_unpin_vma(vma, old_plane_state->fence_id);
> -			old_plane_state->fence_id = -1;
> -		}
> +		old_plane_state->ggtt_vma = NULL;
> +		old_plane_state->fence_id = -1;
>  	} else {
>  		i915_fb_pin_dpt_unpin(fb->dpt,
>  				      old_plane_state->dpt_vma,

-- 
Jani Nikula, Intel