If the sink gets disconnected during receiving a multi-packet DP MST AUX down-reply/up-request sideband message, the state keeping track of which packets have been received already is not reset. This results in a failed sanity check for the subsequent message packet received after a sink is reconnected (due to the pending message not yet completed with an end-of-message-transfer packet), indicated by the "sideband msg set header failed" error. Fix the above by resetting the up/down message reception state after a disconnect event. Cc: Lyude Paul <lyude@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v3.17+ Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 51a46689cda70..90819fff2c9ba 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -3641,6 +3641,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0); ret = 0; mgr->payload_id_table_cleared = false; + + memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv)); + memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv)); } out_unlock: -- 2.37.1