Re: [PATCH 03/11] drm/i915: Extract intel_fb_needs_cpu_access()

[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>
>
> Replace the naked "does the framebuffer have a clear color
> plane?" checks with a more abstract helper that simply tells
> us whether we require CPU access to the framebuffer's memory.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_fb.c | 5 +++++
>  drivers/gpu/drm/i915/display/intel_fb.h | 1 +
>  drivers/gpu/drm/i915/i915_fb_pin.c      | 2 +-
>  drivers/gpu/drm/xe/display/xe_fb_pin.c  | 2 +-
>  4 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
> index c4af368deffd..cbeb39ebdb73 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
> @@ -521,6 +521,11 @@ bool intel_fb_needs_64k_phys(u64 modifier)
>  				      INTEL_PLANE_CAP_NEED64K_PHYS);
>  }
>  
> +bool intel_fb_needs_cpu_access(const struct drm_framebuffer *fb)
> +{
> +	return intel_fb_rc_ccs_cc_plane(fb) >= 0;
> +}
> +
>  /**
>   * intel_fb_is_tile4_modifier: Check if a modifier is a tile4 modifier type
>   * @modifier: Modifier to check
> diff --git a/drivers/gpu/drm/i915/display/intel_fb.h b/drivers/gpu/drm/i915/display/intel_fb.h
> index fc2c4d59bf06..0a027e2595b2 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.h
> +++ b/drivers/gpu/drm/i915/display/intel_fb.h
> @@ -38,6 +38,7 @@ bool intel_fb_is_rc_ccs_cc_modifier(u64 modifier);
>  bool intel_fb_is_mc_ccs_modifier(u64 modifier);
>  bool intel_fb_needs_64k_phys(u64 modifier);
>  bool intel_fb_is_tile4_modifier(u64 modifier);
> +bool intel_fb_needs_cpu_access(const struct drm_framebuffer *fb);
>  
>  bool intel_fb_is_ccs_aux_plane(const struct drm_framebuffer *fb, int color_plane);
>  int intel_fb_rc_ccs_cc_plane(const struct drm_framebuffer *fb);
> diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
> index 4fe6b9859b3f..780be25ad43b 100644
> --- a/drivers/gpu/drm/i915/i915_fb_pin.c
> +++ b/drivers/gpu/drm/i915/i915_fb_pin.c
> @@ -61,7 +61,7 @@ intel_fb_pin_to_dpt(const struct drm_framebuffer *fb,
>  			 * ensure it is always in the mappable part of lmem, if this is
>  			 * a small-bar device.
>  			 */
> -			if (intel_fb_rc_ccs_cc_plane(fb) >= 0)
> +			if (intel_fb_needs_cpu_access(fb))
>  				flags &= ~I915_BO_ALLOC_GPU_ONLY;
>  			ret = __i915_gem_object_migrate(obj, &ww, INTEL_REGION_LMEM_0,
>  							flags);
> diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> index 58cd527e1fde..205492639dba 100644
> --- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
> +++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> @@ -335,7 +335,7 @@ static struct i915_vma *__xe_pin_fb_vma(const struct intel_framebuffer *fb,
>  
>  	refcount_set(&vma->ref, 1);
>  	if (IS_DGFX(to_xe_device(bo->ttm.base.dev)) &&
> -	    intel_fb_rc_ccs_cc_plane(&fb->base) >= 0 &&
> +	    intel_fb_needs_cpu_access(&fb->base) &&
>  	    !(bo->flags & XE_BO_FLAG_NEEDS_CPU_ACCESS)) {
>  		struct xe_vram_region *vram = xe_device_get_root_tile(xe)->mem.vram;

-- 
Jani Nikula, Intel