6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wayne Lin <Wayne.Lin@xxxxxxx> commit ddf983488c3e8d30d5c2e2b315ae7d9cd87096ed upstream. [Why] During resume, observe that we receive CSN event before we start topology probing. Handling CSN at this moment based on uncertain topology is unnecessary. [How] Add checking condition in drm_dp_mst_handle_up_req() to skip handling CSN if the topology is yet to be probed. Cc: Lyude Paul <lyude@xxxxxxxxxx> Cc: Harry Wentland <hwentlan@xxxxxxx> Cc: Jani Nikula <jani.nikula@xxxxxxxxx> Cc: Imre Deak <imre.deak@xxxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Wayne Lin <Wayne.Lin@xxxxxxx> Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20240626084825.878565-3-Wayne.Lin@xxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -4024,6 +4024,7 @@ static int drm_dp_mst_handle_up_req(stru if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) { const struct drm_dp_connection_status_notify *conn_stat = &up_req->msg.u.conn_stat; + bool handle_csn; drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", conn_stat->port_number, @@ -4032,6 +4033,16 @@ static int drm_dp_mst_handle_up_req(stru conn_stat->message_capability_status, conn_stat->input_port, conn_stat->peer_device_type); + + mutex_lock(&mgr->probe_lock); + handle_csn = mgr->mst_primary->link_address_sent; + mutex_unlock(&mgr->probe_lock); + + if (!handle_csn) { + drm_dbg_kms(mgr->dev, "Got CSN before finish topology probing. Skip it."); + kfree(up_req); + goto out; + } } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) { const struct drm_dp_resource_status_notify *res_stat = &up_req->msg.u.resource_stat;
