Commit 608fb0a7 authored by Dave Airlie's avatar Dave Airlie
Browse files

Merge tag 'drm-intel-next-fixes-2026-01-29' of... 

Merge tag 'drm-intel-next-fixes-2026-01-29' of https://gitlab.freedesktop.org/drm/i915/kernel

 into drm-next

- Prevent u64 underflow in intel_fbc_stolen_end

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patch.msgid.link/aXsWGWjacEJ03rTs@jlahtine-mobl
parents 15392f76 ad3ebcc2

drivers/gpu/drm/i915/display/intel_fbc.c

+21 −8
Original line number Diff line number Diff line
@@ -809,19 +809,32 @@ static u64 intel_fbc_cfb_base_max(struct intel_display *display) 


static u64 intel_fbc_stolen_end(struct intel_display *display)

{

	u64 end;

	u64 end = intel_fbc_cfb_base_max(display);



	/* The FBC hardware for BDW/SKL doesn't have access to the stolen

	/*

	 * The FBC hardware for BDW/SKL doesn't have access to the stolen

	 * reserved range size, so it always assumes the maximum (8mb) is used.

	 * If we enable FBC using a CFB on that memory range we'll get FIFO

	 * underruns, even if that range is not reserved by the BIOS. */

	 * underruns, even if that range is not reserved by the BIOS.

	 */

	if (display->platform.broadwell ||

	    (DISPLAY_VER(display) == 9 && !display->platform.broxton))

		end = intel_parent_stolen_area_size(display) - 8 * 1024 * 1024;

	else

		end = U64_MAX;

	    (DISPLAY_VER(display) == 9 && !display->platform.broxton)) {

		u64 stolen_area_size = intel_parent_stolen_area_size(display);



		/*

		 * If stolen_area_size is less than SZ_8M, use

		 * intel_fbc_cfb_base_max instead.  This should not happen,

		 * so warn if it does.

		 */

		if (drm_WARN_ON(display->drm,

				check_sub_overflow(stolen_area_size,

						   SZ_8M, &stolen_area_size)))

			return end;



		return min(end, stolen_area_size);

	}



	return min(end, intel_fbc_cfb_base_max(display));

	return end;

}



static int intel_fbc_min_limit(const struct intel_plane_state *plane_state)