diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index ffc68d305afe..37f360e6ad50 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -336,6 +336,41 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
 }
 EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
 
+/**
+ * drm_dp_send_real_edid_checksum() - send back real edid checksum value
+ * @aux: DisplayPort AUX channel
+ * @real_edid_checksum: real edid checksum for the last block
+ *
+ * Returns true on success
+ */
+bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
+				    u8 real_edid_checksum)
+{
+	u8 link_edid_read = 0, auto_test_req = 0, test_resp = 0;
+
+	drm_dp_dpcd_read(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, &auto_test_req, 1);
+	auto_test_req &= DP_AUTOMATED_TEST_REQUEST;
+
+	drm_dp_dpcd_read(aux, DP_TEST_REQUEST, &link_edid_read, 1);
+	link_edid_read &= DP_TEST_LINK_EDID_READ;
+
+	if (!auto_test_req || !link_edid_read) {
+		DRM_DEBUG_KMS("Source DUT does not support TEST_EDID_READ\n");
+		return false;
+	}
+
+	drm_dp_dpcd_write(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, &auto_test_req, 1);
+
+	/* send back checksum for the last edid extension block data */
+	drm_dp_dpcd_write(aux, DP_TEST_EDID_CHECKSUM, &real_edid_checksum, 1);
+
+	test_resp |= DP_TEST_EDID_CHECKSUM_WRITE;
+	drm_dp_dpcd_write(aux, DP_TEST_RESPONSE, &test_resp, 1);
+
+	return true;
+}
+EXPORT_SYMBOL(drm_dp_send_real_edid_checksum);
+
 /**
  * drm_dp_link_probe() - probe a DisplayPort link for capabilities
  * @aux: DisplayPort AUX channel
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 86603562dba2..e734742486c7 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1358,11 +1358,22 @@ static int validate_displayid(u8 *displayid, int length, int idx);
 static int drm_edid_block_checksum(const u8 *raw_edid)
 {
 	int i;
-	u8 csum = 0;
-	for (i = 0; i < EDID_LENGTH; i++)
+	u8 csum = 0, crc = 0;
+
+	for (i = 0; i < EDID_LENGTH - 1; i++)
 		csum += raw_edid[i];
 
-	return csum;
+	crc = 0x100 - csum;
+
+	return crc;
+}
+
+static bool drm_edid_block_checksum_diff(const u8 *raw_edid, u8 real_checksum)
+{
+	if (raw_edid[EDID_LENGTH - 1] != real_checksum)
+		return true;
+	else
+		return false;
 }
 
 static bool drm_edid_is_zero(const u8 *in_edid, int length)
@@ -1420,7 +1431,7 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid,
 	}
 
 	csum = drm_edid_block_checksum(raw_edid);
-	if (csum) {
+	if (drm_edid_block_checksum_diff(raw_edid, csum)) {
 		if (edid_corrupt)
 			*edid_corrupt = true;
 
@@ -1561,6 +1572,11 @@ static void connector_bad_edid(struct drm_connector *connector,
 			       u8 *edid, int num_blocks)
 {
 	int i;
+	u8 num_of_ext = edid[0x7e];
+
+	/* Calculate real checksum for the last edid extension block data */
+	connector->real_edid_checksum =
+		drm_edid_block_checksum(edid + num_of_ext * EDID_LENGTH);
 
 	if (connector->bad_edid_counter++ && !(drm_debug & DRM_UT_KMS))
 		return;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 555d16fb383b..d1dd028b33fa 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1401,6 +1401,12 @@ struct drm_connector {
 	 * rev1.1 4.2.2.6
 	 */
 	bool edid_corrupt;
+	/**
+	 * @real_edid_checksum: real edid checksum for corrupted edid block.
+	 * Required in Displayport 1.4 compliance testing
+	 * rev1.1 4.2.2.6
+	 */
+	u8 real_edid_checksum;
 
 	/** @debugfs_entry: debugfs directory for this connector */
 	struct dentry *debugfs_entry;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 8b4ff9f26c32..5258e97f071f 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1377,6 +1377,8 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link);
+bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
+				    u8 real_edid_checksum);
 int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
 				const u8 port_cap[4]);
 int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],