Index: backend/pixma_mp730.c
===================================================================
RCS file: /cvsroot/sane/sane-backends/backend/pixma_mp730.c,v
retrieving revision 1.9
diff -u -r1.9 pixma_mp730.c
--- backend/pixma_mp730.c	2 Feb 2009 21:16:44 -0000	1.9
+++ backend/pixma_mp730.c	26 Apr 2009 06:55:31 -0000
@@ -106,6 +106,7 @@
   unsigned imgbuf_len;
 
   unsigned last_block:1;
+  unsigned session_open;
 } mp730_t;
 
 
@@ -452,6 +453,12 @@
     {
     }
 
+  if (s->param->xdpi > 600 && s->param->source == PIXMA_SOURCE_ADF)
+    {
+      PDBG (pixma_dbg (1, "ERROR: maximum resolution of ADF is 600dpi. Requested %udpi\n", s->param->xdpi));
+      return PIXMA_EINVAL;
+    }
+
   mp->raw_width = calc_raw_width (s->param);
   PDBG (pixma_dbg (3, "raw_width = %u\n", mp->raw_width));
 
@@ -465,12 +472,15 @@
   mp->imgbuf_len = 0;
 
   error = step1 (s);
-  if (error >= 0)
-    error = start_session (s);
-  if (error >= 0)
-    mp->state = state_scanning;
-  if (error >= 0)
-    error = select_source (s);
+  if (error >= 0 && ! mp->session_open)
+    {
+      mp->session_open++;
+      error = start_session (s);
+      if (error >= 0)
+        mp->state = state_scanning;
+      if (error >= 0)
+        error = select_source (s);
+    }
   if (error >= 0)
     error = send_scan_param (s);
   if (error < 0)