+
+ ret = drm_dp_decode_sideband_msg_hdr(&hdr, replyblock, len, &hdrlen);
+ if (ret == false) {
+ print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
+ 1, replyblock, len, false);
+ DRM_DEBUG_KMS("ERROR: failed header\n");
+ return false;
+ }
+
+ *seqno = hdr.seqno;
+
+ if (up) {
+ msg = &mgr->up_req_recv;
+ } else {
+ /* Caller is responsible for giving back this reference */
+ *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
+ if (!*mstb) {
+ DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
+ hdr.lct);
+ return false;
+ }
+ msg = &(*mstb)->down_rep_recv[hdr.seqno];
+ }
+
+ if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
+ DRM_DEBUG_KMS("sideband msg set header failed %d\n",
+ replyblock[0]);
+ return false;
+ }
+
+ replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
+ ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);