backport post 1.0.20 xerox_mfp changes 
Index: sane-backends-1.0.20/backend/xerox_mfp.conf.in
===================================================================
--- sane-backends-1.0.20.orig/backend/xerox_mfp.conf.in
+++ sane-backends-1.0.20/backend/xerox_mfp.conf.in
@@ -5,3 +5,25 @@ usb 0x413c 0x5124
 
 #Xerox Phaser 6110MFP
 usb 0x0924 0x3d5d
+
+#Samsung CLX-3170fn
+usb 0x04e8 0x342a
+
+#Samsung SCX-4200
+usb 0x04e8 0x341b
+
+#Samsung SCX4725-FN
+usb 0x04e8 0x341f
+
+#Samsung SCX-4500
+usb 0x04e8 0x3426
+
+# Samsung SCX-4500W
+usb 0x04e8 0x342b
+
+# Samsung SCX-4300
+usb 0x04e8 0x342e
+
+#Xerox WorkCentre 3119 Series
+usb 0x0924 0x4265
+
Index: sane-backends-1.0.20/doc/descriptions/xerox_mfp.desc
===================================================================
--- sane-backends-1.0.20.orig/doc/descriptions/xerox_mfp.desc
+++ sane-backends-1.0.20/doc/descriptions/xerox_mfp.desc
@@ -1,23 +1,25 @@
 :backend "xerox_mfp"
-:version "1.0-9"
+:version "1.0-11"
 :manpage "sane-xerox_mfp"
-:comment "Could be compatible with other Samsung manufactured devices"
 :devicetype :scanner
-:new :yes
 
 :mfg "Xerox"
 :url "http://www.office.xerox.com/"
 
+:model "Phaser 6110MFP"
+:interface "USB"
+:usbid "0x0924" "0x3d5d"
+:status :good
+
 :model "Phaser 3200MFP"
 :interface "USB"
 :usbid "0x0924" "0x3da4"
-:status :good
+:status :complete
 :url "http://www.office.xerox.com/multifunction-printer/multifunction-under-30ppm/phaser-3200mfp/spec-enus.html"
-:comment "All features of device I know of"
 
-:model "Phaser 6110MFP"
+:model "WorkCentre 3119 Series"
 :interface "USB"
-:usbid "0x0924" "0x3d5d"
+:usbid "0x0924" "0x4265"
 :status :good
 
 :mfg "Dell"
@@ -28,3 +30,30 @@
 :usbid "0x413c" "0x5124"
 :status :good
 
+:mfg "Samsung"
+:url "http://www.samsung.com"
+
+:model "SCX-4200"
+:interface "USB"
+:usbid "0x04e8" "0x341b"
+:status :good
+
+:model "SCX4725-FN"
+:interface "USB"
+:usbid "0x04e8" "0x341f"
+:status :good
+
+:model "SCX-4500"
+:interface "USB"
+:usbid "0x04e8" "0x3426"
+:status :good
+
+:model "CLX-3170fn"
+:interface "USB"
+:usbid "0x04e8" "0x342a"
+:status :good
+
+:model "SCX-4300"
+:interface "USB"
+:usbid "0x04e8" "0x342e"
+:status :good
Index: sane-backends-1.0.20/backend/xerox_mfp.c
===================================================================
--- sane-backends-1.0.20.orig/backend/xerox_mfp.c
+++ sane-backends-1.0.20/backend/xerox_mfp.c
@@ -26,7 +26,7 @@
 #include <sane/sanei_backend.h>
 #include "xerox_mfp.h"
 
-#define BACKEND_BUILD 10
+#define BACKEND_BUILD 11
 #define XEROX_CONFIG_FILE "xerox_mfp.conf"
 
 static const SANE_Device **devlist = NULL;	/* sane_get_devices array */
@@ -802,7 +802,7 @@ sane_control_option (SANE_Handle h, SANE
   }
 
   DBG (4, "%s: %d, <%d> => %08x, %x\n", __FUNCTION__, opt, act,
-       *(SANE_Word *)val, info? *info : 0);
+       val? *(SANE_Word *)val : 0, info? *info : 0);
   return SANE_STATUS_GOOD;
 }
 
@@ -1319,14 +1319,15 @@ sane_start (SANE_Handle h)
     dev->reserved++;
   }
 
-  if (!dev_set_window(dev))
+  if (!dev_set_window(dev) ||
+      (dev->state && dev->state != SANE_STATUS_DEVICE_BUSY))
     return dev_stop(dev);
 
   if (!dev_cmd_wait(dev, CMD_OBJECT_POSITION))
     return dev_stop(dev);
 
   if (!dev_cmd(dev, CMD_READ) ||
-      dev->state != SANE_STATUS_DEVICE_BUSY)
+      (dev->state && dev->state != SANE_STATUS_DEVICE_BUSY))
     return dev_stop(dev);
 
   dev->scanning = 1;