expected_size = 37;
        } else if (i915->display.vbt.version <= 215) {
                expected_size = 38;
-       } else if (i915->display.vbt.version <= 250) {
+       } else if (i915->display.vbt.version <= 255) {
                expected_size = 39;
+       } else if (i915->display.vbt.version <= 256) {
+               expected_size = 40;
        } else {
                expected_size = sizeof(*child);
-               BUILD_BUG_ON(sizeof(*child) < 39);
+               BUILD_BUG_ON(sizeof(*child) < 40);
                drm_dbg(&i915->drm,
                        "Expected child device config size for VBT version %u not known; assuming %u\n",
                        i915->display.vbt.version, expected_size);
 
        u8 hdmi_iboost_level:4;                                 /* 196+ */
        u8 dp_max_link_rate:3;                                  /* 216+ */
        u8 dp_max_link_rate_reserved:5;                         /* 216+ */
+       u8 efp_index;                                           /* 256+ */
 } __packed;
 
 struct bdb_general_definitions {