serial: dump DMM packets during stream detection

Regular operation of serial DMM drivers optionally can dump packet bytes
after the intialization phase has synchronized to the stream. Failure to
synchronize to the stream left developers without a dump, which complicates
research what went wrong.

Do dump packet content while the serial_stream_detect() routine tries to
synchronize to the stream. Use the spew level since the dump occurs upon
every attempt, which translates to: every received byte until a valid
packet was seen (or the synchronization phase expired).

diff --git a/src/serial.c b/src/serial.c
index 3c7ab643b6d6dfb6a75c2ac7797fc6c87eaf02a2..ca46ea51ca405ddfe59b13ea1e7e19ab46f22bcf 100644 (file)
--- a/src/serial.c
+++ b/src/serial.c
@@ -715,7 +715,11 @@ SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
                time /= 1000;
 
                if ((ibuf - i) >= packet_size) {
+                       GString *text;
                        /* We have at least a packet's worth of data. */
+                       text = sr_hexdump_new(&buf[i], packet_size);
+                       sr_spew("Trying DMM packet: %s", text->str);
+                       sr_hexdump_free(text);
                        if (is_valid(&buf[i])) {
                                sr_spew("Found valid %zu-byte packet after "
                                        "%" PRIu64 "ms.", (ibuf - i), time);