Re: [PATCH 07/11] drm/i915: Introduce pin_params.needs_physical

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

On Thu, 16 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Add a new flag pin_params.needs_physical to inform the pinning
> code that the display needs a physical address and not GGTT
> address.
>
> This isn't strictly necessary as the current phys_alignment!=0
> check is enough in practice. But theoretically one could have
> needs_physical==true without any alignment requirements. And
> having an explicit flag feels a bit less magical.

Agreed.

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


>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fb_pin.h | 1 +
>  drivers/gpu/drm/i915/i915_fb_pin.c          | 3 ++-
>  2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.h b/drivers/gpu/drm/i915/display/intel_fb_pin.h
> index cf54a96569de..3e37e9874f50 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb_pin.h
> +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.h
> @@ -21,6 +21,7 @@ struct intel_fb_pin_params {
>  	unsigned int vtd_guard;
>  	bool needs_cpu_lmem_access;
>  	bool needs_low_address;
> +	bool needs_physical;
>  };
>  
>  struct i915_vma *
> diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
> index 97e4cdfd2447..bfe9a5342e13 100644
> --- a/drivers/gpu/drm/i915/i915_fb_pin.c
> +++ b/drivers/gpu/drm/i915/i915_fb_pin.c
> @@ -148,7 +148,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
>  	i915_gem_ww_ctx_init(&ww, true);
>  retry:
>  	ret = i915_gem_object_lock(obj, &ww);
> -	if (!ret && pin_params->phys_alignment)
> +	if (!ret && pin_params->needs_physical)
>  		ret = i915_gem_object_attach_phys(obj, pin_params->phys_alignment);
>  	else if (!ret && HAS_LMEM(i915))
>  		ret = i915_gem_object_migrate(obj, &ww, INTEL_REGION_LMEM_0);
> @@ -271,6 +271,7 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state,
>  			.vtd_guard = intel_plane_fb_vtd_guard(plane_state),
>  			.needs_cpu_lmem_access = intel_fb_needs_cpu_access(&fb->base),
>  			.needs_low_address = intel_plane_needs_low_address(display),
> +			.needs_physical = intel_plane_needs_physical(plane),
>  		};
>  		int fence_id = -1;

-- 
Jani Nikula, Intel