1 files changed, 72 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 273dd80fabf3..e68d23043973 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -76,6 +76,11 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
 
 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 				    struct drm_dp_mst_branch *mstb);
+
+static void
+drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
+				   struct drm_dp_mst_branch *mstb);
+
 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 					   struct drm_dp_mst_branch *mstb,
 					   struct drm_dp_mst_port *port);
@@ -517,8 +522,10 @@ drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 			}
 
 			if (failed) {
-				for (i = 0; i < r->num_transactions; i++)
+				for (i = 0; i < r->num_transactions; i++) {
+					tx = &r->transactions[i];
 					kfree(tx->bytes);
+				}
 				return -ENOMEM;
 			}
 
@@ -950,6 +957,8 @@ static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 	case DP_POWER_DOWN_PHY:
 	case DP_POWER_UP_PHY:
 		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
+	case DP_CLEAR_PAYLOAD_ID_TABLE:
+		return true; /* since there's nothing to parse */
 	default:
 		DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
 			  drm_dp_mst_req_type_str(msg->req_type));
@@ -1048,6 +1057,15 @@ static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
 	return 0;
 }
 
+static int build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
+{
+	struct drm_dp_sideband_msg_req_body req;
+
+	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
+	drm_dp_encode_sideband_req(&req, msg);
+	return 0;
+}
+
 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
 {
 	struct drm_dp_sideband_msg_req_body req;
@@ -2520,10 +2538,14 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work)
 	struct drm_device *dev = mgr->dev;
 	struct drm_dp_mst_branch *mstb;
 	int ret;
+	bool clear_payload_id_table;
 
 	mutex_lock(&mgr->probe_lock);
 
 	mutex_lock(&mgr->lock);
+	clear_payload_id_table = !mgr->payload_id_table_cleared;
+	mgr->payload_id_table_cleared = true;
+
 	mstb = mgr->mst_primary;
 	if (mstb) {
 		ret = drm_dp_mst_topology_try_get_mstb(mstb);
@@ -2536,6 +2558,19 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work)
 		return;
 	}
 
+	/*
+	 * Certain branch devices seem to incorrectly report an available_pbn
+	 * of 0 on downstream sinks, even after clearing the
+	 * DP_PAYLOAD_ALLOCATE_* registers in
+	 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
+	 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
+	 * things work again.
+	 */
+	if (clear_payload_id_table) {
+		DRM_DEBUG_KMS("Clearing payload ID table\n");
+		drm_dp_send_clear_payload_id_table(mgr, mstb);
+	}
+
 	ret = drm_dp_check_and_send_link_address(mgr, mstb);
 	drm_dp_mst_topology_put_mstb(mstb);
 
@@ -2859,6 +2894,28 @@ out:
 	return ret < 0 ? ret : changed;
 }
 
+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;
+
+	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
+	if (!txmsg)
+		return;
+
+	txmsg->dst = mstb;
+	len = build_clear_payload_id_table(txmsg);
+
+	drm_dp_queue_down_tx(mgr, txmsg);
+
+	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
+	if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
+		DRM_DEBUG_KMS("clear payload table id nak received\n");
+
+	kfree(txmsg);
+}
+
 static int
 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 				struct drm_dp_mst_branch *mstb,
@@ -3388,6 +3445,7 @@ static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
 {
 	int ret = 0;
+	int i = 0;
 	struct drm_dp_mst_branch *mstb = NULL;
 
 	mutex_lock(&mgr->lock);
@@ -3448,10 +3506,23 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		/* this can fail if the device is gone */
 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
 		ret = 0;
+		mutex_lock(&mgr->payload_lock);
 		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
 		mgr->payload_mask = 0;
 		set_bit(0, &mgr->payload_mask);
+		for (i = 0; i < mgr->max_payloads; i++) {
+			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
+
+			if (vcpi) {
+				vcpi->vcpi = 0;
+				vcpi->num_slots = 0;
+			}
+			mgr->proposed_vcpis[i] = NULL;
+		}
 		mgr->vcpi_mask = 0;
+		mutex_unlock(&mgr->payload_lock);
+
+		mgr->payload_id_table_cleared = false;
 	}
 
 out_unlock: