drm/display/dp_mst: Fix down/up message handling after sink disconnect

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@redhat.com>
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-1-imre.deak@intel.com

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 51a46689cda70f0b7e2ae8471a6ec410546844b2..90819fff2c9ba19eab191ad3d84f252c218cf3cf 100644 (file)
--- 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: