Re: [PATCH 09/10] drm/i915: Completely reject DPT BIOS FBs.

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

On Fri, 10 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Our BIOS FB handling can't deal with DPT, and instead everything
> just assumes a direct GGTT mapping. Reject any BIOS FB using DPT.
> Most likely this should never happen anyway.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Seems cleaner.

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


> ---
>  drivers/gpu/drm/i915/display/intel_initial_plane.c | 9 +++++++++
>  drivers/gpu/drm/i915/display/skl_universal_plane.c | 6 ------
>  2 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_initial_plane.c b/drivers/gpu/drm/i915/display/intel_initial_plane.c
> index 55b6cdded126..e3d1b2d1669c 100644
> --- a/drivers/gpu/drm/i915/display/intel_initial_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_initial_plane.c
> @@ -92,6 +92,15 @@ intel_alloc_initial_plane_obj(struct intel_display *display,
>  		return NULL;
>  	}
>  
> +	/*
> +	 * Would need to preserve the DPT, its GGTT
> +	 * mapping, and the actual FB memory.
> +	 */
> +	if (intel_fb_modifier_uses_dpt(display, fb->modifier)) {
> +		drm_dbg_kms(display->drm, "DPT not supported for initial FB\n");
> +		return NULL;
> +	}
> +
>  	return display->parent->initial_plane->alloc_obj(display->drm, plane_config);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index 00c863e378a1..5aef8123d8b8 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -3148,12 +3148,6 @@ skl_get_initial_plane_config(struct intel_crtc *crtc,
>  
>  	fb->format = drm_get_format_info(display->drm, fourcc, fb->modifier);
>  
> -	if (!display->params.enable_dpt &&
> -	    intel_fb_modifier_uses_dpt(display, fb->modifier)) {
> -		drm_dbg_kms(display->drm, "DPT disabled, skipping initial FB\n");
> -		goto error;
> -	}
> -
>  	/*
>  	 * DRM_MODE_ROTATE_ is counter clockwise to stay compatible with Xrandr
>  	 * while i915 HW rotation is clockwise, that's why this swapping.

-- 
Jani Nikula, Intel