hp-3478a: Only match when conn= is given to avoid false probe positives.

[libsigrok.git] / src / hardware / hp-3478a / api.c

diff --git a/src/hardware/hp-3478a/api.c b/src/hardware/hp-3478a/api.c
index f9419a6e09ced36fb7625a24990b2a50ae4387e4..1fd3ff203ad7a872fa451a7361fc1485d277a019 100644 (file)
--- a/src/hardware/hp-3478a/api.c
+++ b/src/hardware/hp-3478a/api.c
@@ -129,6 +129,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
        struct sr_dev_inst *sdi;
        struct dev_context *devc;
 
+       /*
+        * The device cannot get identified by means of SCPI queries.
+        * Neither shall non-SCPI requests get emitted before reliable
+        * identification of the device. Assume that we only get here
+        * when user specs led us to believe it's safe to communicate
+        * to the expected kind of device.
+        */
+
        sdi = g_malloc0(sizeof(struct sr_dev_inst));
        sdi->vendor = g_strdup("Hewlett-Packard");
        sdi->model = g_strdup("3478A");
@@ -152,6 +160,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 {
+       const char *conn;
+
+       /* Only scan for a device when conn= was specified. */
+       conn = NULL;
+       (void)sr_serial_extract_options(options, &conn, NULL);
+       if (!conn)
+               return NULL;
+
        return sr_scpi_scan(di->context, options, probe_device);
 }