--- a/master/cdev.c	Thu Jun 05 12:39:46 2008 +0000
+++ b/master/cdev.c	Thu Jun 05 14:33:36 2008 +0000
@@ -449,6 +449,12 @@
                 break;
             }
 
+        case EC_IOCTL_DEBUG_LEVEL:
+            if (ec_master_debug_level(master, (unsigned int) arg)) {
+                retval = -EINVAL;
+            }
+            break;
+
         default:
             retval = -ENOIOCTLCMD;
     }

--- a/master/ioctl.h	Thu Jun 05 12:39:46 2008 +0000
+++ b/master/ioctl.h	Thu Jun 05 14:33:36 2008 +0000
@@ -52,7 +52,8 @@
 	EC_IOCTL_DOMAIN_COUNT,
 	EC_IOCTL_DOMAIN,
 	EC_IOCTL_DOMAIN_FMMU,
-	EC_IOCTL_DATA
+	EC_IOCTL_DATA,
+    EC_IOCTL_DEBUG_LEVEL,
 };
 
 /*****************************************************************************/

--- a/master/master.c	Thu Jun 05 12:39:46 2008 +0000
+++ b/master/master.c	Thu Jun 05 14:33:36 2008 +0000
@@ -65,25 +65,20 @@
 void ec_master_eoe_run(unsigned long);
 #endif
 ssize_t ec_show_master_attribute(struct kobject *, struct attribute *, char *);
-ssize_t ec_store_master_attribute(struct kobject *, struct attribute *,
-                                  const char *, size_t);
 
 /*****************************************************************************/
 
 /** \cond */
 
 EC_SYSFS_READ_ATTR(info);
-EC_SYSFS_READ_WRITE_ATTR(debug_level);
 
 static struct attribute *ec_def_attrs[] = {
     &attr_info,
-    &attr_debug_level,
     NULL,
 };
 
 static struct sysfs_ops ec_sysfs_ops = {
     .show = &ec_show_master_attribute,
-    .store = ec_store_master_attribute
 };
 
 static struct kobj_type ktype_ec_master = {
@@ -1085,52 +1080,12 @@
     if (attr == &attr_info) {
         return ec_master_info(master, buffer);
     }
-    else if (attr == &attr_debug_level) {
-        return sprintf(buffer, "%i\n", master->debug_level);
-    }
 
     return 0;
 }
 
 /*****************************************************************************/
 
-/**
-   Formats attribute data for SysFS write access.
-   \return number of bytes processed, or negative error code
-*/
-
-ssize_t ec_store_master_attribute(struct kobject *kobj, /**< slave's kobject */
-                                  struct attribute *attr, /**< attribute */
-                                  const char *buffer, /**< memory with data */
-                                  size_t size /**< size of data to store */
-                                  )
-{
-    ec_master_t *master = container_of(kobj, ec_master_t, kobj);
-
-    if (attr == &attr_debug_level) {
-        if (!strcmp(buffer, "0\n")) {
-            master->debug_level = 0;
-        }
-        else if (!strcmp(buffer, "1\n")) {
-            master->debug_level = 1;
-        }
-        else if (!strcmp(buffer, "2\n")) {
-            master->debug_level = 2;
-        }
-        else {
-            EC_ERR("Invalid debug level value!\n");
-            return -EINVAL;
-        }
-
-        EC_INFO("Master debug level set to %i.\n", master->debug_level);
-        return size;
-    }
-
-    return -EINVAL;
-}
-
-/*****************************************************************************/
-
 #ifdef EC_EOE
 /**
    Starts Ethernet-over-EtherCAT processing on demand.
@@ -1339,6 +1294,26 @@
 	return NULL;
 }
 
+/*****************************************************************************/
+
+int ec_master_debug_level(
+        ec_master_t *master,
+        int level
+        )
+{
+    if (level < 0 || level > 2) {
+        EC_ERR("Invalid debug level %i!\n", level);
+        return -1;
+    }
+
+    if (level != master->debug_level) {
+        master->debug_level = level;
+        EC_INFO("Master debug level set to %i.\n", master->debug_level);
+    }
+
+    return 0;
+}
+
 /******************************************************************************
  *  Realtime interface
  *****************************************************************************/

--- a/master/master.h	Thu Jun 05 12:39:46 2008 +0000
+++ b/master/master.h	Thu Jun 05 14:33:36 2008 +0000
@@ -126,7 +126,7 @@
 
     struct list_head domains; /**< list of domains */
 
-    int debug_level; /**< master debug level */
+    int debug_level; /**< Master debug level. */
     ec_stats_t stats; /**< cyclic statistics */
     unsigned int frames_timed_out; /**< there were frame timeouts in the last
                                      call to ecrt_master_receive() */
@@ -200,6 +200,8 @@
 unsigned int ec_master_domain_count(const ec_master_t *);
 ec_domain_t *ec_master_find_domain(ec_master_t *, unsigned int);
 
-/*****************************************************************************/
-
-#endif
+int ec_master_debug_level(ec_master_t *, int);
+
+/*****************************************************************************/
+
+#endif

--- a/tools/Master.cpp	Thu Jun 05 12:39:46 2008 +0000
+++ b/tools/Master.cpp	Thu Jun 05 14:33:36 2008 +0000
@@ -77,6 +77,35 @@
 
 /****************************************************************************/
 
+void Master::setDebug(const vector<string> &commandArgs)
+{
+    stringstream str;
+    int debugLevel;
+    
+    if (commandArgs.size() != 1) {
+        stringstream err;
+        err << "'debug' takes exactly one argument!";
+        throw MasterException(err.str());
+    }
+
+    str << commandArgs[0];
+    str >> debugLevel;
+
+    if (str.fail()) {
+        stringstream err;
+        err << "Invalid debug level '" << commandArgs[0] << "'!";
+        throw MasterException(err.str());
+    }
+
+    if (ioctl(fd, EC_IOCTL_DEBUG_LEVEL, debugLevel) < 0) {
+        stringstream err;
+        err << "Failed to set debug level: " << strerror(errno);
+        throw MasterException(err.str());
+    }
+}
+
+/****************************************************************************/
+
 void Master::showDomains(int domainIndex)
 {
     if (domainIndex == -1) {

--- a/tools/Master.h	Thu Jun 05 12:39:46 2008 +0000
+++ b/tools/Master.h	Thu Jun 05 14:33:36 2008 +0000
@@ -8,6 +8,8 @@
 #define __EC_MASTER_H__
 
 #include <stdexcept>
+#include <string>
+#include <vector>
 using namespace std;
 
 #include "../master/ioctl.h"
@@ -41,6 +43,7 @@
         void close();
 
         void outputData(int);
+        void setDebug(const vector<string> &);
         void showDomains(int);
         void listSlaves();
         void listPdos(int);

--- a/tools/main.cpp	Thu Jun 05 12:39:46 2008 +0000
+++ b/tools/main.cpp	Thu Jun 05 14:33:36 2008 +0000
@@ -8,6 +8,7 @@
 
 #include <iostream>
 #include <string>
+#include <vector>
 using namespace std;
 
 #include "Master.h"
@@ -23,6 +24,7 @@
 static int slavePosition = DEFAULT_SLAVEPOSITION;
 static int domainIndex = DEFAULT_DOMAININDEX;
 static string command = DEFAULT_COMMAND;
+vector<string> commandArgs;
 
 /*****************************************************************************/
 
@@ -32,6 +34,7 @@
         << "Usage: ethercat <COMMAND> [OPTIONS]" << endl
 		<< "Commands:" << endl
         << "  data               Output binary domain process data." << endl
+        << "  debug              Set the master debug level." << endl
         << "  domain             Show domain information." << endl
         << "  list (ls, slaves)  List all slaves (former 'lsec')." << endl
         << "  pdos               List Pdo mapping of given slaves." << endl
@@ -131,6 +134,8 @@
 	}
 
     command = argv[optind];
+    while (++optind < argc)
+        commandArgs.push_back(string(argv[optind]));
 }
 
 /****************************************************************************/
@@ -146,6 +151,8 @@
 
         if (command == "data") {
             master.outputData(domainIndex);
+        } else if (command == "debug") {
+            master.setDebug(commandArgs);
         } else if (command == "domain") {
             master.showDomains(domainIndex);
 		} else if (command == "list" || command == "ls" || command == "slaves") {