diff options
| -rw-r--r-- | drivers/platform/surface/aggregator/ssh_packet_layer.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 74f0faaa2b27..583315db8b02 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -1694,7 +1694,24 @@ static size_t ssh_ptl_rx_eval(struct ssh_ptl *ptl, struct ssam_span *source) /* Find SYN. */ syn_found = sshp_find_syn(source, &aligned); - if (unlikely(aligned.ptr - source->ptr) > 0) { + if (unlikely(aligned.ptr != source->ptr)) { + /* + * We expect aligned.ptr == source->ptr. If this is not the + * case, then aligned.ptr > source->ptr and we've encountered + * some unexpected data where we'd expect the start of a new + * message (i.e. the SYN sequence). + * + * This can happen when a CRC check for the previous message + * failed and we start actively searching for the next one + * (via the call to sshp_find_syn() above), or the first bytes + * of a message got dropped or corrupted. + * + * In any case, we issue a warning, send a NAK to the EC to + * request re-transmission of any data we haven't acknowledged + * yet, and finally, skip everything up to the next SYN + * sequence. + */ + ptl_warn(ptl, "rx: parser: invalid start of frame, skipping\n"); /* |