Second try to fix problem with null-pointer in sane_control_option

backend/hp-option.c

@@ -3910,7 +3910,7 @@ sanei_hp_optset_control (HpOptSet this, HpData data,
                          hp_bool_t immediate)
 {
   HpOption	opt  = hp_optset_getByIndex(this, optnum);
-  SANE_Int	my_info = 0;
+  SANE_Int	my_info = 0, my_val = 0;
 
   DBG(3,"sanei_hp_optset_control: %s\n", opt ? opt->descriptor->name : "");
 
@@ -3922,6 +3922,23 @@ sanei_hp_optset_control (HpOptSet this, HpData data,
   if (!opt)
       return SANE_STATUS_INVAL;
 
+  /* There are problems with SANE_ACTION_GET_VALUE and valp == 0. */
+  /* Check if we really need valp. */
+  if ((action == SANE_ACTION_GET_VALUE) && (!valp))
+  {
+    /* Options without a value ? */
+    if (   (opt->descriptor->type == SANE_TYPE_BUTTON)
+        || (opt->descriptor->type == SANE_TYPE_GROUP))
+    {
+      valp = &my_val; /* Just simulate a return value locally. */
+    }
+    else /* Others must return a value. So this is invalid */
+    {
+      DBG(1, "sanei_hp_optset_control: get value, but valp == 0\n");
+      return SANE_STATUS_INVAL;
+    }
+  }
+
   if (immediate)
     RETURN_IF_FAIL( hp_option_imm_control(this, opt, data, action, valp, infop,
                                           scsi) );

backend/hp.c

@@ -883,29 +883,6 @@ sane_control_option (SANE_Handle handle, SANE_Int optnum,
 
   DBG(10, "sane_control_option called\n");
 
-  status = SANE_STATUS_GOOD;
-  switch (action)
-  {
-    case SANE_ACTION_GET_VALUE:
-    case SANE_ACTION_SET_VALUE:
-           if (!valp)
-           {
-             DBG (1,"sane_control_option: valp is NULL\n");
-             status = SANE_STATUS_INVAL;
-           }
-           break;
-
-    case SANE_ACTION_SET_AUTO:
-           break;
-
-    default:
-           DBG (1,"sane_control_option: action unknown\n");
-           status = SANE_STATUS_INVAL;
-           break;
-  }
-
-  if (status != SANE_STATUS_GOOD) return status;
-
   status = sanei_hp_handle_control(h, optnum, action, valp, info);
 
   DBG(10, "sane_control_option will finish with %s\n",