diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index a811247cecfe..ba15a15bce9e 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1035,7 +1035,8 @@ static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
 	}
 }
 
-static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
+static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
+			     u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
 {
 	struct drm_dp_sideband_msg_req_body req;
 
@@ -1045,17 +1046,14 @@ static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32
 	req.u.dpcd_write.num_bytes = num_bytes;
 	req.u.dpcd_write.bytes = bytes;
 	drm_dp_encode_sideband_req(&req, msg);
-
-	return 0;
 }
 
-static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
+static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
 {
 	struct drm_dp_sideband_msg_req_body req;
 
 	req.req_type = DP_LINK_ADDRESS;
 	drm_dp_encode_sideband_req(&req, msg);
-	return 0;
 }
 
 static int build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
@@ -1067,7 +1065,8 @@ static int build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
 	return 0;
 }
 
-static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
+static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
+				     int port_num)
 {
 	struct drm_dp_sideband_msg_req_body req;
 
@@ -1078,10 +1077,11 @@ static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int por
 	return 0;
 }
 
-static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
-				  u8 vcpi, uint16_t pbn,
-				  u8 number_sdp_streams,
-				  u8 *sdp_stream_sink)
+static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
+				   int port_num,
+				   u8 vcpi, uint16_t pbn,
+				   u8 number_sdp_streams,
+				   u8 *sdp_stream_sink)
 {
 	struct drm_dp_sideband_msg_req_body req;
 	memset(&req, 0, sizeof(req));
@@ -1094,11 +1094,10 @@ static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_n
 		   number_sdp_streams);
 	drm_dp_encode_sideband_req(&req, msg);
 	msg->path_msg = true;
-	return 0;
 }
 
-static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
-				  int port_num, bool power_up)
+static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
+				   int port_num, bool power_up)
 {
 	struct drm_dp_sideband_msg_req_body req;
 
@@ -1110,7 +1109,6 @@ static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
 	req.u.port_num.port_number = port_num;
 	drm_dp_encode_sideband_req(&req, msg);
 	msg->path_msg = true;
-	return 0;
 }
 
 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
@@ -2073,29 +2071,24 @@ ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
 				      offset, size, buffer);
 }
 
-static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
+static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
 {
-	int ret;
+	int ret = 0;
 
 	memcpy(mstb->guid, guid, 16);
 
 	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
 		if (mstb->port_parent) {
-			ret = drm_dp_send_dpcd_write(
-					mstb->mgr,
-					mstb->port_parent,
-					DP_GUID,
-					16,
-					mstb->guid);
+			ret = drm_dp_send_dpcd_write(mstb->mgr,
+						     mstb->port_parent,
+						     DP_GUID, 16, mstb->guid);
 		} else {
-
-			ret = drm_dp_dpcd_write(
-					mstb->mgr->aux,
-					DP_GUID,
-					mstb->guid,
-					16);
+			ret = drm_dp_dpcd_write(mstb->mgr->aux,
+						DP_GUID, mstb->guid, 16);
 		}
 	}
+
+	return ret;
 }
 
 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
@@ -2645,7 +2638,8 @@ static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
 	return false;
 }
 
-static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
+static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
+			    u8 port_num, u32 offset, u8 num_bytes)
 {
 	struct drm_dp_sideband_msg_req_body req;
 
@@ -2654,8 +2648,6 @@ static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32
 	req.u.dpcd_read.dpcd_address = offset;
 	req.u.dpcd_read.num_bytes = num_bytes;
 	drm_dp_encode_sideband_req(&req, msg);
-
-	return 0;
 }
 
 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
@@ -2881,7 +2873,7 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 	struct drm_dp_sideband_msg_tx *txmsg;
 	struct drm_dp_link_address_ack_reply *reply;
 	struct drm_dp_mst_port *port, *tmp;
-	int i, len, ret, port_mask = 0;
+	int i, ret, port_mask = 0;
 	bool changed = false;
 
 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
@@ -2889,7 +2881,7 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 		return -ENOMEM;
 
 	txmsg->dst = mstb;
-	len = build_link_address(txmsg);
+	build_link_address(txmsg);
 
 	mstb->link_address_sent = true;
 	drm_dp_queue_down_tx(mgr, txmsg);
@@ -2910,7 +2902,9 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 	DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
 	drm_dp_dump_link_address(reply);
 
-	drm_dp_check_mstb_guid(mstb, reply->guid);
+	ret = drm_dp_check_mstb_guid(mstb, reply->guid);
+	if (ret)
+		goto out;
 
 	for (i = 0; i < reply->nports; i++) {
 		port_mask |= BIT(reply->ports[i].port_number);
@@ -2951,14 +2945,14 @@ void drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
 					struct drm_dp_mst_branch *mstb)
 {
 	struct drm_dp_sideband_msg_tx *txmsg;
-	int len, ret;
+	int ret;
 
 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
 	if (!txmsg)
 		return;
 
 	txmsg->dst = mstb;
-	len = build_clear_payload_id_table(txmsg);
+	build_clear_payload_id_table(txmsg);
 
 	drm_dp_queue_down_tx(mgr, txmsg);
 
@@ -2976,7 +2970,6 @@ drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 {
 	struct drm_dp_enum_path_resources_ack_reply *path_res;
 	struct drm_dp_sideband_msg_tx *txmsg;
-	int len;
 	int ret;
 
 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
@@ -2984,7 +2977,7 @@ drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 		return -ENOMEM;
 
 	txmsg->dst = mstb;
-	len = build_enum_path_resources(txmsg, port->port_num);
+	build_enum_path_resources(txmsg, port->port_num);
 
 	drm_dp_queue_down_tx(mgr, txmsg);
 
@@ -3068,7 +3061,7 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
 {
 	struct drm_dp_sideband_msg_tx *txmsg;
 	struct drm_dp_mst_branch *mstb;
-	int len, ret, port_num;
+	int ret, port_num;
 	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
 	int i;
 
@@ -3093,9 +3086,9 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
 		sinks[i] = i;
 
 	txmsg->dst = mstb;
-	len = build_allocate_payload(txmsg, port_num,
-				     id,
-				     pbn, port->num_sdp_streams, sinks);
+	build_allocate_payload(txmsg, port_num,
+			       id,
+			       pbn, port->num_sdp_streams, sinks);
 
 	drm_dp_queue_down_tx(mgr, txmsg);
 
@@ -3124,7 +3117,7 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port, bool power_up)
 {
 	struct drm_dp_sideband_msg_tx *txmsg;
-	int len, ret;
+	int ret;
 
 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
 	if (!port)
@@ -3137,7 +3130,7 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
 	}
 
 	txmsg->dst = port->parent;
-	len = build_power_updown_phy(txmsg, port->port_num, power_up);
+	build_power_updown_phy(txmsg, port->port_num, power_up);
 	drm_dp_queue_down_tx(mgr, txmsg);
 
 	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
@@ -3359,7 +3352,6 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port,
 				 int offset, int size, u8 *bytes)
 {
-	int len;
 	int ret = 0;
 	struct drm_dp_sideband_msg_tx *txmsg;
 	struct drm_dp_mst_branch *mstb;
@@ -3374,7 +3366,7 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
 		goto fail_put;
 	}
 
-	len = build_dpcd_read(txmsg, port->port_num, offset, size);
+	build_dpcd_read(txmsg, port->port_num, offset, size);
 	txmsg->dst = port->parent;
 
 	drm_dp_queue_down_tx(mgr, txmsg);
@@ -3412,7 +3404,6 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
 				  struct drm_dp_mst_port *port,
 				  int offset, int size, u8 *bytes)
 {
-	int len;
 	int ret;
 	struct drm_dp_sideband_msg_tx *txmsg;
 	struct drm_dp_mst_branch *mstb;
@@ -3427,7 +3418,7 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
 		goto fail_put;
 	}
 
-	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
+	build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
 	txmsg->dst = mstb;
 
 	drm_dp_queue_down_tx(mgr, txmsg);
@@ -3673,7 +3664,12 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
 		DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
 		goto out_fail;
 	}
-	drm_dp_check_mstb_guid(mgr->mst_primary, guid);
+
+	ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
+	if (ret) {
+		DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
+		goto out_fail;
+	}
 
 	/*
 	 * For the final step of resuming the topology, we need to bring the
@@ -4615,15 +4611,34 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
 		int ret;
 
 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
+		if (ret) {
+			seq_printf(m, "dpcd read failed\n");
+			goto out;
+		}
 		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
+
 		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
+		if (ret) {
+			seq_printf(m, "faux/mst read failed\n");
+			goto out;
+		}
 		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
+
 		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
+		if (ret) {
+			seq_printf(m, "mst ctrl read failed\n");
+			goto out;
+		}
 		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
 
 		/* dump the standard OUI branch header */
 		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
+		if (ret) {
+			seq_printf(m, "branch oui read failed\n");
+			goto out;
+		}
 		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
+
 		for (i = 0x3; i < 0x8 && buf[i]; i++)
 			seq_printf(m, "%c", buf[i]);
 		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
@@ -4632,6 +4647,7 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
 			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
 	}
 
+out:
 	mutex_unlock(&mgr->lock);
 
 }