Index: usb-libusb.c
===================================================================
--- usb-libusb.c	(revision 10087)
+++ usb-libusb.c	(working copy)
@@ -631,6 +631,7 @@
             int           verbose)	/* I - Update connecting-to-device state? */
 {
   int	number;				/* Configuration/interface/altset numbers */
+  char current_bConfiguration;
 
 
  /*
@@ -647,27 +648,40 @@
   if ((printer->handle = usb_open(printer->device)) == NULL)
     return (-1);
 
- /*
-  * Then set the desired configuration...
-  */
 
   if (verbose)
     fputs("STATE: +connecting-to-device\n", stderr);
 
+ /*
+  * Set the desired configuration, but only if it needs changing. Some
+  * printers (e.g., Samsung) don't like usb_set_configuration. It will succeed,
+  * but the following print job is sometimes silently lost by the printer.
+  */
+  if (usb_control_msg(printer->handle,
+                USB_TYPE_STANDARD | USB_ENDPOINT_IN | USB_RECIP_DEVICE,
+                8, /* GET_CONFIGURATION */
+                0, 0, &current_bConfiguration, 1, 5000) != 1)
+  {
+    current_bConfiguration = 0;   /* Failed. Assume not configured */
+  }
+    
   number = printer->device->config[printer->conf].bConfigurationValue;
-
-  if (usb_set_configuration(printer->handle, number) < 0)
+  if (number != current_bConfiguration)
   {
-   /*
-    * If the set fails, chances are that the printer only supports a
-    * single configuration.  Technically these printers don't conform to
-    * the USB printer specification, but otherwise they'll work...
-    */
 
-    if (errno != EBUSY)
-      fprintf(stderr, "DEBUG: Failed to set configuration %d for %04x:%04x\n",
-              number, printer->device->descriptor.idVendor,
-	      printer->device->descriptor.idProduct);
+    if (usb_set_configuration(printer->handle, number) < 0)
+    {
+     /*
+      * If the set fails, chances are that the printer only supports a
+      * single configuration.  Technically these printers don't conform to
+      * the USB printer specification, but otherwise they'll work...
+      */
+
+      if (errno != EBUSY)
+        fprintf(stderr, "DEBUG: Failed to set configuration %d for %04x:%04x\n",
+                number, printer->device->descriptor.idVendor,
+	        printer->device->descriptor.idProduct);
+    }
   }
 
  /*
@@ -700,20 +714,24 @@
 #endif /* 0 */
 
  /*
-  * Set alternate setting...
+  * Set alternate setting, but only if there is more than one option.
+  * Some printers (e.g., Samsung) don't like usb_set_altinterface.
   */
-
-  number = printer->device->config[printer->conf].interface[printer->iface].
-               altsetting[printer->altset].bAlternateSetting;
-  while (usb_set_altinterface(printer->handle, number) < 0)
+  if (printer->device->config[printer->conf].interface[printer->iface].
+          num_altsetting > 1)
   {
-    if (errno != EBUSY)
-      fprintf(stderr,
-              "DEBUG: Failed to set alternate interface %d for %04x:%04x: %s\n",
-              number, printer->device->descriptor.idVendor,
-	      printer->device->descriptor.idProduct, strerror(errno));
+    number = printer->device->config[printer->conf].interface[printer->iface].
+                 altsetting[printer->altset].bAlternateSetting;
+    while (usb_set_altinterface(printer->handle, number) < 0)
+    {
+      if (errno != EBUSY)
+        fprintf(stderr,
+                "DEBUG: Failed to set alternate interface %d for %04x:%04x: %s\n",
+                number, printer->device->descriptor.idVendor,
+	        printer->device->descriptor.idProduct, strerror(errno));
 
-    goto error;
+      goto error;
+    }
   }
 
   if (verbose)