diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 796985609933..7a251905b3c4 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2048,24 +2048,40 @@ static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm 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) +/* + * Searches upwards in the topology starting from mstb to try to find the + * closest available parent of mstb that's still connected to the rest of the + * topology. This can be used in order to perform operations like releasing + * payloads, where the branch device which owned the payload may no longer be + * around and thus would require that the payload on the last living relative + * be freed instead. + */ +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) { + if (!mgr->mst_primary) + goto out; + + do { found_port = drm_dp_get_last_connected_port_to_mstb(mstb); + if (!found_port) + break; - if (found_port) { + if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) { rmstb = found_port->parent; - if (drm_dp_mst_topology_try_get_mstb(rmstb)) - *port_num = found_port->port_num; - else - rmstb = NULL; + *port_num = found_port->port_num; + } else { + /* Search again, starting from this parent */ + mstb = found_port->parent; } - } + } while (!rmstb); +out: mutex_unlock(&mgr->lock); return rmstb; } @@ -2114,6 +2130,14 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, drm_dp_queue_down_tx(mgr, txmsg); + /* + * FIXME: there is a small chance that between getting the last + * connected mstb and sending the payload message, the last connected + * mstb could also be removed from the topology. In the future, this + * needs to be fixed by restarting the + * drm_dp_get_last_connected_port_and_mstb() search in the event of a + * timeout if the topology is still connected to the system. + */ ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); if (ret > 0) { if (txmsg->reply.reply_type == 1) |