drm/display/dp_mst: Fix down message handling after a packet reception error

commit 1241aedb6b upstream.

After an error during receiving a packet for a multi-packet DP MST
sideband message, the state tracking which packets have been received
already is not reset. This prevents the reception of subsequent down
messages (due to the pending message not yet completed with an
end-of-message-transfer packet).

Fix the above by resetting the reception state after a packet error.

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/20221214184258.2869417-2-imre.deak@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/drm_dp_mst_topology.c

@@ -3997,7 +3997,7 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
 
 	if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
-		goto out;
+		goto out_clear_reply;
 
 	/* Multi-packet message transmission, don't clear the reply */
 	if (!msg->have_eomt)