1 files changed, 83 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 7e5d98c7b908..8ae13de272c4 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -803,6 +803,18 @@ static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
         return mstb;
 }
 
+static void drm_dp_free_mst_port(struct kref *kref);
+
+static void drm_dp_free_mst_branch_device(struct kref *kref)
+{
+        struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
+        if (mstb->port_parent) {
+                if (list_empty(&mstb->port_parent->next))
+                        kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port);
+        }
+        kfree(mstb);
+}
+
 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
 {
         struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
@@ -810,6 +822,15 @@ static void drm_dp_destroy_mst_branch_device(struct kref *kref)
         bool wake_tx = false;
 
         /*
+         * init kref again to be used by ports to remove mst branch when it is
+         * not needed anymore
+         */
+        kref_init(kref);
+
+        if (mstb->port_parent && list_empty(&mstb->port_parent->next))
+                kref_get(&mstb->port_parent->kref);
+
+        /*
          * destroy all ports - don't need lock
          * as there are no more references to the mst branch
          * device at this point.
@@ -835,7 +856,8 @@ static void drm_dp_destroy_mst_branch_device(struct kref *kref)
 
         if (wake_tx)
                 wake_up(&mstb->mgr->tx_waitq);
-        kfree(mstb);
+
+        kref_put(kref, drm_dp_free_mst_branch_device);
 }
 
 static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
@@ -883,6 +905,7 @@ static void drm_dp_destroy_port(struct kref *kref)
                          * from an EDID retrieval */
 
                         mutex_lock(&mgr->destroy_connector_lock);
+                        kref_get(&port->parent->kref);
                         list_add(&port->next, &mgr->destroy_connector_list);
                         mutex_unlock(&mgr->destroy_connector_lock);
                         schedule_work(&mgr->destroy_connector_work);
@@ -1617,6 +1640,37 @@ static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
         return 0;
 }
 
+static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
+{
+        if (!mstb->port_parent)
+                return NULL;
+
+        if (mstb->port_parent->mstb != mstb)
+                return mstb->port_parent;
+
+        return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
+}
+
+static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
+                                                                         struct drm_dp_mst_branch *mstb,
+                                                                         int *port_num)
+{
+        struct drm_dp_mst_branch *rmstb = NULL;
+        struct drm_dp_mst_port *found_port;
+        mutex_lock(&mgr->lock);
+        if (mgr->mst_primary) {
+                found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
+
+                if (found_port) {
+                        rmstb = found_port->parent;
+                        kref_get(&rmstb->kref);
+                        *port_num = found_port->port_num;
+                }
+        }
+        mutex_unlock(&mgr->lock);
+        return rmstb;
+}
+
 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
                                    struct drm_dp_mst_port *port,
                                    int id,
@@ -1624,13 +1678,18 @@ 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;
+        int len, ret, port_num;
         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
         int i;
 
+        port_num = port->port_num;
         mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
-        if (!mstb)
-                return -EINVAL;
+        if (!mstb) {
+                mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
+
+                if (!mstb)
+                        return -EINVAL;
+        }
 
         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
         if (!txmsg) {
@@ -1642,7 +1701,7 @@ 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->port_num,
+        len = build_allocate_payload(txmsg, port_num,
                                      id,
                                      pbn, port->num_sdp_streams, sinks);
 
@@ -2788,6 +2847,13 @@ static void drm_dp_tx_work(struct work_struct *work)
         mutex_unlock(&mgr->qlock);
 }
 
+static void drm_dp_free_mst_port(struct kref *kref)
+{
+        struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
+        kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
+        kfree(port);
+}
+
 static void drm_dp_destroy_connector_work(struct work_struct *work)
 {
         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
@@ -2808,13 +2874,22 @@ static void drm_dp_destroy_connector_work(struct work_struct *work)
                 list_del(&port->next);
                 mutex_unlock(&mgr->destroy_connector_lock);
 
+                kref_init(&port->kref);
+                INIT_LIST_HEAD(&port->next);
+
                 mgr->cbs->destroy_connector(mgr, port->connector);
 
                 drm_dp_port_teardown_pdt(port, port->pdt);
 
-                if (!port->input && port->vcpi.vcpi > 0)
-                        drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
-                kfree(port);
+                if (!port->input && port->vcpi.vcpi > 0) {
+                        if (mgr->mst_state) {
+                                drm_dp_mst_reset_vcpi_slots(mgr, port);
+                                drm_dp_update_payload_part1(mgr);
+                                drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
+                        }
+                }
+
+                kref_put(&port->kref, drm_dp_free_mst_port);
                 send_hotplug = true;
         }
         if (send_hotplug)