hameg-hmo: Try to find a valid serialcomm if none is supplied.

If no serial port option is specified on the command-line using the
"serialcomm" driver option, but the device is connected through USB
and it requires a known default serial port option, then use it in
order to avoid data corruption or even worse problems.

Note: the easiest way to reproduce data corruption on HMO3000 series
is to start an analog data acquisition (e.g. on channel CH1) after
switching from Ethernet mode to USB VCP mode (HO732 USB/Ethernet interface).

This fixes parts of bug #1321.

diff --git a/src/scpi/scpi_serial.c b/src/scpi/scpi_serial.c
index c73d1b4841a70ae434f50a6222d3555d881828ee..8690d6f146485ab65b7cc2a737b17708e101f1b7 100644 (file)
--- a/src/scpi/scpi_serial.c
+++ b/src/scpi/scpi_serial.c
@@ -74,11 +74,30 @@ static GSList *scpi_serial_scan(struct drv_context *drvc)
 static int scpi_serial_dev_inst_new(void *priv, struct drv_context *drvc,
                const char *resource, char **params, const char *serialcomm)
 {
+       GSList *l, *r;
+       unsigned i;
        struct scpi_serial *sscpi = priv;
 
        (void)drvc;
        (void)params;
 
+       /* If no serial port option is specified on the command-line using the
+        * "serialcomm" driver option, but the device is connected through USB
+        * and it requires a known default serial port option, then used it in
+        * order to avoid data corruption or even worse problems.
+        */
+       if (!serialcomm) {
+               for (i = 0; i < ARRAY_SIZE(scpi_serial_usb_ids); i++) {
+                       if (!(l = sr_serial_find_usb(scpi_serial_usb_ids[i].vendor_id,
+                                               scpi_serial_usb_ids[i].product_id)))
+                               continue;
+                       for (r = l; r; r = r->next)
+                               if (!strcmp(resource, r->data) && scpi_serial_usb_ids[i].serialcomm)
+                                       serialcomm = scpi_serial_usb_ids[i].serialcomm;
+                       g_slist_free_full(l, g_free);
+               }
+       }
+
        sscpi->serial = sr_serial_dev_inst_new(resource, serialcomm);
 
        return SR_OK;