X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fscpi%2Fscpi.c;h=f72164a63f177dce0b71dd5d07fbc312566dadd8;hb=72cd558d4ac706d4d3f934d177c58d0aa0e806fa;hp=31f82a3f912351c2bc653bb66dfed90f6e61a6db;hpb=1df81f4b062fcfe8c6de4d2e5edf9743030ae0fc;p=libsigrok.git

diff --git a/src/scpi/scpi.c b/src/scpi/scpi.c
index 31f82a3f..f72164a6 100644
--- a/src/scpi/scpi.c
+++ b/src/scpi/scpi.c
@@ -961,6 +961,7 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
 {
 	int ret;
 	GString* response;
+	gsize oldlen;
 	char buf[10];
 	long llen;
 	long datalen;
@@ -990,14 +991,14 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
 	*scpi_response = NULL;
 
 	/* Get (the first chunk of) the response. */
-	while (response->len < 2) {
+	do {
 		ret = scpi_read_response(scpi, response, timeout);
 		if (ret < 0) {
 			g_mutex_unlock(&scpi->scpi_mutex);
 			g_string_free(response, TRUE);
 			return ret;
 		}
-	}
+	} while (response->len < 2);
 
 	/*
 	 * SCPI protocol data blocks are preceeded with a length spec.
@@ -1044,25 +1045,33 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
 	g_string_erase(response, 0, 2 + llen);
 
 	/*
-	 * If the initially assumed length does not cover the data block
-	 * length, then re-allocate the buffer size to the now known
-	 * length, and keep reading more chunks of response data.
+	 * Re-allocate the buffer size to the now known length
+	 * and keep reading more chunks of response data.
 	 */
-	if (response->len < (unsigned long)(datalen)) {
-		int oldlen = response->len;
-		g_string_set_size(response, datalen);
-		g_string_set_size(response, oldlen);
-	}
-
-	while (response->len < (unsigned long)(datalen)) {
-		ret = scpi_read_response(scpi, response, timeout);
-		if (ret < 0) {
-			g_mutex_unlock(&scpi->scpi_mutex);
-			g_string_free(response, TRUE);
-			return ret;
-		}
-		if (ret > 0)
-			timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+	oldlen = response->len;
+	g_string_set_size(response, datalen);
+	g_string_set_size(response, oldlen);
+
+	if (oldlen < (unsigned long)(datalen)) {
+		do {
+			oldlen = response->len;
+			ret = scpi_read_response(scpi, response, timeout);
+
+			/* On timeout truncate the buffer and send the partial response
+			 * instead of getting stuck on timeouts...
+			 */
+			if (ret == SR_ERR_TIMEOUT) {
+				datalen = oldlen;
+				break;
+			}
+			if (ret < 0) {
+				g_mutex_unlock(&scpi->scpi_mutex);
+				g_string_free(response, TRUE);
+				return ret;
+			}
+			if (ret > 0)
+				timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+		} while (response->len < (unsigned long)(datalen));
 	}
 
 	g_mutex_unlock(&scpi->scpi_mutex);
@@ -1105,15 +1114,24 @@ SR_PRIV int sr_scpi_get_hw_id(struct sr_scpi_dev_inst *scpi,
 	 * The response to a '*IDN?' is specified by the SCPI spec. It contains
 	 * a comma-separated list containing the manufacturer name, instrument
 	 * model, serial number of the instrument and the firmware version.
+	 *
+	 * BEWARE! Although strictly speaking a smaller field count is invalid,
+	 * this implementation also accepts IDN responses with one field less,
+	 * and assumes that the serial number is missing. Some GWInstek DMMs
+	 * were found to do this. Keep warning about this condition, which may
+	 * need more consideration later.
 	 */
 	tokens = g_strsplit(response, ",", 0);
 	num_tokens = g_strv_length(tokens);
-	if (num_tokens < 4) {
-		sr_dbg("IDN response not according to spec: %80.s.", response);
+	if (num_tokens < 3) {
+		sr_dbg("IDN response not according to spec: '%s'", response);
 		g_strfreev(tokens);
 		g_free(response);
 		return SR_ERR_DATA;
 	}
+	if (num_tokens < 4) {
+		sr_warn("Short IDN response, assume missing serial number.");
+	}
 	g_free(response);
 
 	hw_info = g_malloc0(sizeof(struct sr_scpi_hw_info));
@@ -1125,8 +1143,13 @@ SR_PRIV int sr_scpi_get_hw_id(struct sr_scpi_dev_inst *scpi,
 		hw_info->manufacturer = g_strstrip(g_strdup(idn_substr + 4));
 
 	hw_info->model = g_strstrip(g_strdup(tokens[1]));
-	hw_info->serial_number = g_strstrip(g_strdup(tokens[2]));
-	hw_info->firmware_version = g_strstrip(g_strdup(tokens[3]));
+	if (num_tokens < 4) {
+		hw_info->serial_number = g_strdup("Unknown");
+		hw_info->firmware_version = g_strstrip(g_strdup(tokens[2]));
+	} else {
+		hw_info->serial_number = g_strstrip(g_strdup(tokens[2]));
+		hw_info->firmware_version = g_strstrip(g_strdup(tokens[3]));
+	}
 
 	g_strfreev(tokens);