diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8c52cbdb76f314092520a17778e72e54918d6f59..9868a66ef59c8c0b7dfd92bbbed7eb119e19e5bc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1090,7 +1090,7 @@ struct intel_vbt_data {
 	int crt_ddc_pin;
 
 	int child_dev_num;
-	struct child_device_config *child_dev;
+	union child_device_config *child_dev;
 };
 
 enum intel_ddb_partitioning {
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 6668873fb3a87a8fd6786274b228552547cb362e..33003b97f1f027134bf79ce30e5160fb755cdd3f 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -389,7 +389,7 @@ parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
 {
 	struct sdvo_device_mapping *p_mapping;
 	struct bdb_general_definitions *p_defs;
-	struct child_device_config *p_child;
+	union child_device_config *p_child;
 	int i, child_device_num, count;
 	u16	block_size;
 
@@ -416,36 +416,36 @@ parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
 	count = 0;
 	for (i = 0; i < child_device_num; i++) {
 		p_child = &(p_defs->devices[i]);
-		if (!p_child->device_type) {
+		if (!p_child->old.device_type) {
 			/* skip the device block if device type is invalid */
 			continue;
 		}
-		if (p_child->slave_addr != SLAVE_ADDR1 &&
-			p_child->slave_addr != SLAVE_ADDR2) {
+		if (p_child->old.slave_addr != SLAVE_ADDR1 &&
+			p_child->old.slave_addr != SLAVE_ADDR2) {
 			/*
 			 * If the slave address is neither 0x70 nor 0x72,
 			 * it is not a SDVO device. Skip it.
 			 */
 			continue;
 		}
-		if (p_child->dvo_port != DEVICE_PORT_DVOB &&
-			p_child->dvo_port != DEVICE_PORT_DVOC) {
+		if (p_child->old.dvo_port != DEVICE_PORT_DVOB &&
+			p_child->old.dvo_port != DEVICE_PORT_DVOC) {
 			/* skip the incorrect SDVO port */
 			DRM_DEBUG_KMS("Incorrect SDVO port. Skip it\n");
 			continue;
 		}
 		DRM_DEBUG_KMS("the SDVO device with slave addr %2x is found on"
 				" %s port\n",
-				p_child->slave_addr,
-				(p_child->dvo_port == DEVICE_PORT_DVOB) ?
+				p_child->old.slave_addr,
+				(p_child->old.dvo_port == DEVICE_PORT_DVOB) ?
 					"SDVOB" : "SDVOC");
-		p_mapping = &(dev_priv->sdvo_mappings[p_child->dvo_port - 1]);
+		p_mapping = &(dev_priv->sdvo_mappings[p_child->old.dvo_port - 1]);
 		if (!p_mapping->initialized) {
-			p_mapping->dvo_port = p_child->dvo_port;
-			p_mapping->slave_addr = p_child->slave_addr;
-			p_mapping->dvo_wiring = p_child->dvo_wiring;
-			p_mapping->ddc_pin = p_child->ddc_pin;
-			p_mapping->i2c_pin = p_child->i2c_pin;
+			p_mapping->dvo_port = p_child->old.dvo_port;
+			p_mapping->slave_addr = p_child->old.slave_addr;
+			p_mapping->dvo_wiring = p_child->old.dvo_wiring;
+			p_mapping->ddc_pin = p_child->old.ddc_pin;
+			p_mapping->i2c_pin = p_child->old.i2c_pin;
 			p_mapping->initialized = 1;
 			DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d\n",
 				      p_mapping->dvo_port,
@@ -457,7 +457,7 @@ parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
 			DRM_DEBUG_KMS("Maybe one SDVO port is shared by "
 					 "two SDVO device.\n");
 		}
-		if (p_child->slave2_addr) {
+		if (p_child->old.slave2_addr) {
 			/* Maybe this is a SDVO device with multiple inputs */
 			/* And the mapping info is not added */
 			DRM_DEBUG_KMS("there exists the slave2_addr. Maybe this"
@@ -588,7 +588,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
 		       struct bdb_header *bdb)
 {
 	struct bdb_general_definitions *p_defs;
-	struct child_device_config *p_child, *child_dev_ptr;
+	union child_device_config *p_child, *child_dev_ptr;
 	int i, child_device_num, count;
 	u16	block_size;
 
@@ -616,7 +616,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
 	/* get the number of child device that is present */
 	for (i = 0; i < child_device_num; i++) {
 		p_child = &(p_defs->devices[i]);
-		if (!p_child->device_type) {
+		if (!p_child->common.device_type) {
 			/* skip the device block if device type is invalid */
 			continue;
 		}
@@ -636,7 +636,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
 	count = 0;
 	for (i = 0; i < child_device_num; i++) {
 		p_child = &(p_defs->devices[i]);
-		if (!p_child->device_type) {
+		if (!p_child->common.device_type) {
 			/* skip the device block if device type is invalid */
 			continue;
 		}
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 6e9250eb9c2c4b02fd2837d45420b2de2411b7ef..1da2bf208299727000116adef78d7802de4e2a5e 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -202,7 +202,10 @@ struct bdb_general_features {
 #define DEVICE_PORT_DVOB	0x01
 #define DEVICE_PORT_DVOC	0x02
 
-struct child_device_config {
+/* We used to keep this struct but without any version control. We should avoid
+ * using it in the future, but it should be safe to keep using it in the old
+ * code. */
+struct old_child_dev_config {
 	u16 handle;
 	u16 device_type;
 	u8  device_id[10]; /* ascii string */
@@ -224,6 +227,32 @@ struct child_device_config {
 	u8  dvo_function;
 } __attribute__((packed));
 
+/* This one contains field offsets that are known to be common for all BDB
+ * versions. Notice that the meaning of the contents contents may still change,
+ * but at least the offsets are consistent. */
+struct common_child_dev_config {
+	u16 handle;
+	u16 device_type;
+	u8 not_common1[12];
+	u8 dvo_port;
+	u8 not_common2[2];
+	u8 ddc_pin;
+	u16 edid_ptr;
+} __attribute__((packed));
+
+/* This field changes depending on the BDB version, so the most reliable way to
+ * read it is by checking the BDB version and reading the raw pointer. */
+union child_device_config {
+	/* This one is safe to be used anywhere, but the code should still check
+	 * the BDB version. */
+	u8 raw[33];
+	/* This one should only be kept for legacy code. */
+	struct old_child_dev_config old;
+	/* This one should also be safe to use anywhere, even without version
+	 * checks. */
+	struct common_child_dev_config common;
+};
+
 struct bdb_general_definitions {
 	/* DDC GPIO */
 	u8 crt_ddc_gmbus_pin;
@@ -249,7 +278,7 @@ struct bdb_general_definitions {
 	 * number = (block_size - sizeof(bdb_general_definitions))/
 	 *	     sizeof(child_device_config);
 	 */
-	struct child_device_config devices[0];
+	union child_device_config devices[0];
 } __attribute__((packed));
 
 struct bdb_lvds_options {
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7e4052ea99c56a51b86d3973c20f3bcbd3ba3332..7823a1b5c7a6e1a2d539dc4049d268310d9a772b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3203,7 +3203,7 @@ intel_trans_dp_port_sel(struct drm_crtc *crtc)
 bool intel_dpd_is_edp(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct child_device_config *p_child;
+	union child_device_config *p_child;
 	int i;
 
 	if (!dev_priv->vbt.child_dev_num)
@@ -3212,8 +3212,8 @@ bool intel_dpd_is_edp(struct drm_device *dev)
 	for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
 		p_child = dev_priv->vbt.child_dev + i;
 
-		if (p_child->dvo_port == PORT_IDPD &&
-		    p_child->device_type == DEVICE_TYPE_eDP)
+		if (p_child->common.dvo_port == PORT_IDPD &&
+		    p_child->common.device_type == DEVICE_TYPE_eDP)
 			return true;
 	}
 	return false;
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 639650c66e59a4a220b5a827c6e93bef8c7c14d4..67a4a8fd5f898bd4a91ea8397c82e34e2c3fa737 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -794,7 +794,8 @@ static bool lvds_is_present_in_vbt(struct drm_device *dev,
 		return true;
 
 	for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
-		struct child_device_config *child = dev_priv->vbt.child_dev + i;
+		union child_device_config *uchild = dev_priv->vbt.child_dev + i;
+		struct old_child_dev_config *child = &uchild->old;
 
 		/* If the device type is not LFP, continue.
 		 * We have to check both the new identifiers as well as the
diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index e6e93ce34f7bf5ba57bb8f2765686e5aeb501027..11c15fbf9e55586a02570cdeb8b4db7edd7a6891 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1518,7 +1518,7 @@ static const struct drm_encoder_funcs intel_tv_enc_funcs = {
 static int tv_is_present_in_vbt(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct child_device_config *p_child;
+	union child_device_config *p_child;
 	int i, ret;
 
 	if (!dev_priv->vbt.child_dev_num)
@@ -1530,13 +1530,13 @@ static int tv_is_present_in_vbt(struct drm_device *dev)
 		/*
 		 * If the device type is not TV, continue.
 		 */
-		if (p_child->device_type != DEVICE_TYPE_INT_TV &&
-			p_child->device_type != DEVICE_TYPE_TV)
+		if (p_child->old.device_type != DEVICE_TYPE_INT_TV &&
+			p_child->old.device_type != DEVICE_TYPE_TV)
 			continue;
 		/* Only when the addin_offset is non-zero, it is regarded
 		 * as present.
 		 */
-		if (p_child->addin_offset) {
+		if (p_child->old.addin_offset) {
 			ret = 1;
 			break;
 		}