Re: [PATCH 03/14] drm/i915: Throw away the BIOS fb if has the wrong depth/bpp

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

On Tue, 12 May 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Respect the user's choice of depth/bpp for the fbdev framebuffer
> and throw out the fb we inherited from the BIOS if it doesn't
> match.

Seems reasonable, although I admit I might not be aware of all the
consequences here.

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

>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbdev.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index f9c135400453..3754810cc187 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -268,6 +268,8 @@ static bool bios_fb_ok(const struct intel_framebuffer *fb,
>  	struct intel_display *display = to_intel_display(fb->base.dev);
>  	int width = fb->base.width;
>  	int height = fb->base.height;
> +	int depth = fb->base.format->depth;
> +	int bpp = fb->base.format->cpp[0] * 8;
>  
>  	if (sizes->fb_width > width || sizes->fb_height > height) {
>  		drm_dbg_kms(display->drm,
> @@ -276,6 +278,13 @@ static bool bios_fb_ok(const struct intel_framebuffer *fb,
>  		return false;
>  	}
>  
> +	if (sizes->surface_depth != depth || sizes->surface_bpp != bpp) {
> +		drm_dbg_kms(display->drm,
> +			    "BIOS fb using wrong depth/bpp (%d/%d), we require (%d/%d), releasing it\n",
> +			    depth, bpp, sizes->surface_depth, sizes->surface_bpp);
> +		return false;
> +	}
> +
>  	return true;
>  }

-- 
Jani Nikula, Intel