@@ -257,27 +257,49 @@ struct old_child_dev_config {
u8 dvo_function;
} __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. */
+/*
+ * The child device config, aka the display device data structure, provides a
+ * description of a port and its configuration on the platform.
+ *
+ * The child device config size has been increased, and fields have been added
+ * and their meaning has changed over time. Care must be taken when accessing
+ * basically any of the fields to ensure the correct interpretation for the BDB
+ * version in question.
+ *
+ * When we copy the child device configs to dev_priv->vbt.child_dev, we reserve
+ * space for the full structure below, and initialize the tail not actually
+ * present in VBT to zeros. Accessing those fields is fine, as long as the
+ * default zero is taken into account, again according to the BDB version.
+ *
+ * BDB versions 155 and below are considered legacy, and version 155 seems to be
+ * a baseline for some of the VBT documentation. When adding new fields, please
+ * include the BDB version when the field was added, if it's above that.
+ */
struct common_child_dev_config {
u16 handle;
u16 device_type;
- u8 i2c_speed;
- u8 dp_onboard_redriver; /* 158 */
- u8 dp_ondock_redriver; /* 158 */
- u8 hdmi_level_shifter_value:4; /* 169 */
- u8 hdmi_max_data_rate:4; /* 204 */
- u16 dtd_buf_ptr; /* 161 */
- u8 edidless_efp:1; /* 161 */
- u8 compression_enable:1; /* 198 */
- u8 compression_method:1; /* 198 */
- u8 ganged_edp:1; /* 202 */
- u8 reserved0:4;
- u8 compression_structure_index:4; /* 198 */
- u8 reserved1:4;
- u8 slave_port; /* 202 */
- u8 reserved2;
+
+ union {
+ u8 device_id[10]; /* ascii string */
+ struct {
+ u8 i2c_speed;
+ u8 dp_onboard_redriver; /* 158 */
+ u8 dp_ondock_redriver; /* 158 */
+ u8 hdmi_level_shifter_value:4; /* 169 */
+ u8 hdmi_max_data_rate:4; /* 204 */
+ u16 dtd_buf_ptr; /* 161 */
+ u8 edidless_efp:1; /* 161 */
+ u8 compression_enable:1; /* 198 */
+ u8 compression_method:1; /* 198 */
+ u8 ganged_edp:1; /* 202 */
+ u8 reserved0:4;
+ u8 compression_structure_index:4; /* 198 */
+ u8 reserved1:4;
+ u8 slave_port; /* 202 */
+ u8 reserved2;
+ } __packed;
+ } __packed;
+
u16 addin_offset;
u8 dvo_port;
u8 i2c_pin;
@@ -285,21 +307,38 @@ struct common_child_dev_config {
u8 ddc_pin;
u16 edid_ptr;
u8 dvo_cfg; /* See DEVICE_CFG_* above */
- u8 efp_routed:1; /* 158 */
- u8 lane_reversal:1; /* 184 */
- u8 lspcon:1; /* 192 */
- u8 iboost:1; /* 196 */
- u8 hpd_invert:1; /* 196 */
- u8 flag_reserved:3;
- u8 hdmi_support:1; /* 158 */
- u8 dp_support:1; /* 158 */
- u8 tmds_support:1; /* 158 */
- u8 support_reserved:5;
- u8 aux_channel;
- u8 dongle_detect;
+
+ union {
+ struct {
+ u8 dvo2_port;
+ u8 i2c2_pin;
+ u8 slave2_addr;
+ u8 ddc2_pin;
+ } __packed;
+ struct {
+ u8 efp_routed:1; /* 158 */
+ u8 lane_reversal:1; /* 184 */
+ u8 lspcon:1; /* 192 */
+ u8 iboost:1; /* 196 */
+ u8 hpd_invert:1; /* 196 */
+ u8 flag_reserved:3;
+ u8 hdmi_support:1; /* 158 */
+ u8 dp_support:1; /* 158 */
+ u8 tmds_support:1; /* 158 */
+ u8 support_reserved:5;
+ u8 aux_channel;
+ u8 dongle_detect;
+ } __packed;
+ } __packed;
+
u8 capabilities;
u8 dvo_wiring; /* See DEVICE_WIRE_* above */
- u8 mipi_bridge_type; /* 171 */
+
+ union {
+ u8 dvo2_wiring;
+ u8 mipi_bridge_type; /* 171 */
+ } __packed;
+
u16 extended_type;
u8 dvo_function;
u8 flags2; /* 195 */