Re: [PATCH 06/11] drm/i915: Introduce pin_params.needs_low_address

[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_low_address to inform the pinning
> code that the display needs a low ggtt address.
>
> The goal is to eliminate all display specific stuff from
> the low level pinning code (the direct intel_plane_needs_low_addres())
> call in this case).

So this one initializes .needs_low_address only where needed. I guess my
main concern is that the calling code does need to know the low-level
implementation detail of when you do need to initialize it.

Regardless, I think overall this is going in the right direction.

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/display/intel_fbdev.c  | 2 ++
>  drivers/gpu/drm/i915/i915_fb_pin.c          | 4 +++-
>  3 files changed, 6 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 bcf5a1f46092..cf54a96569de 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb_pin.h
> +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.h
> @@ -20,6 +20,7 @@ struct intel_fb_pin_params {
>  	unsigned int phys_alignment;
>  	unsigned int vtd_guard;
>  	bool needs_cpu_lmem_access;
> +	bool needs_low_address;
>  };
>  
>  struct i915_vma *
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index 136fa827c8f0..4c3e54acde81 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -55,6 +55,7 @@
>  #include "intel_fb_pin.h"
>  #include "intel_fbdev.h"
>  #include "intel_frontbuffer.h"
> +#include "intel_plane.h"
>  
>  struct intel_fbdev {
>  	struct intel_framebuffer *fb;
> @@ -314,6 +315,7 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
>  	pin_params.vtd_guard = intel_fb_view_vtd_guard(&fb->base,
>  						       &fb->normal_view,
>  						       DRM_MODE_ROTATE_0);
> +	pin_params.needs_low_address = intel_plane_needs_low_address(display);
>  
>  	vma = intel_fb_pin_to_ggtt(&fb->base, &pin_params, NULL);
>  	if (IS_ERR(vma)) {
> diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
> index a3e5107c12f0..97e4cdfd2447 100644
> --- a/drivers/gpu/drm/i915/i915_fb_pin.c
> +++ b/drivers/gpu/drm/i915/i915_fb_pin.c
> @@ -142,7 +142,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
>  
>  	pinctl = 0;
>  	/* PIN_MAPPABLE limits the address to GMADR size */
> -	if (intel_plane_needs_low_address(display))
> +	if (pin_params->needs_low_address)
>  		pinctl |= PIN_MAPPABLE;
>  
>  	i915_gem_ww_ctx_init(&ww, true);
> @@ -256,6 +256,7 @@ intel_plane_fb_vtd_guard(const struct intel_plane_state *plane_state)
>  int intel_plane_pin_fb(struct intel_plane_state *plane_state,
>  		       const struct intel_plane_state *old_plane_state)
>  {
> +	struct intel_display *display = to_intel_display(plane_state);
>  	struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);
>  	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
>  	const struct intel_framebuffer *fb =
> @@ -269,6 +270,7 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state,
>  			.phys_alignment = intel_plane_fb_min_phys_alignment(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),
>  		};
>  		int fence_id = -1;

-- 
Jani Nikula, Intel