Merge branch 'master' of ettus.sourcerepo.com:ettus/uhdpriv into usrp_e

19 files changed, 588 insertions, 126 deletions

diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index 26d275845..77b04af0c 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -77,17 +77,38 @@ INCLUDE(${CMAKE_CURRENT_SOURCE_DIR}/usrp/usrp_e/CMakeLists.txt)
 ########################################################################
 # Setup defines for process scheduling
 ########################################################################
-MESSAGE(STATUS "Configuring process scheduling...")
+MESSAGE(STATUS "Configuring priority scheduling...")
+
+INCLUDE(CheckCXXSourceCompiles)
+CHECK_CXX_SOURCE_COMPILES("
+    #include <pthread.h>
+    int main(){
+        struct sched_param sp;
+        pthread_setschedparam(pthread_self(), SCHED_RR, &sp);
+        return 0;
+    }
+    " HAVE_PTHREAD_SETSCHEDPARAM
+)
 
-INCLUDE(CheckIncludeFileCXX)
-CHECK_INCLUDE_FILE_CXX(sched.h HAVE_SCHED_H)
+CHECK_CXX_SOURCE_COMPILES("
+    #include <windows.h>
+    int main(){
+        SetThreadPriority(GetCurrentThread(), 0);
+        SetPriorityClass(GetCurrentProcess(), 0);
+        return 0;
+    }
+    " HAVE_WIN_SETTHREADPRIORITY
+)
 
-IF(HAVE_SCHED_H)
-    MESSAGE(STATUS "  Process scheduling supported through sched_setscheduler.")
-    ADD_DEFINITIONS(-DHAVE_SCHED_H)
-ELSE(HAVE_SCHED_H)
-    MESSAGE(STATUS "  Process scheduling not supported.")
-ENDIF(HAVE_SCHED_H)
+IF(HAVE_PTHREAD_SETSCHEDPARAM)
+    MESSAGE(STATUS "  Priority scheduling supported through pthread_setschedparam.")
+    ADD_DEFINITIONS(-DHAVE_PTHREAD_SETSCHEDPARAM)
+ELSEIF(HAVE_WIN_SETTHREADPRIORITY)
+    MESSAGE(STATUS "  Priority scheduling supported through windows SetThreadPriority.")
+    ADD_DEFINITIONS(-DHAVE_WIN_SETTHREADPRIORITY)
+ELSE(HAVE_PTHREAD_SETSCHEDPARAM)
+    MESSAGE(STATUS "  Priority scheduling not supported.")
+ENDIF(HAVE_PTHREAD_SETSCHEDPARAM)
 
 ########################################################################
 # Setup defines for module loading
@@ -115,7 +136,7 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_CURRENT_SOURCE_DIR}/device.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/gain_handler.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/load_modules.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/sched.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/thread_priority.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/types.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/utils.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/wax.cpp
diff --git a/host/lib/load_modules.cpp b/host/lib/load_modules.cpp
index d6bfe1369..dbb8d0695 100644
--- a/host/lib/load_modules.cpp
+++ b/host/lib/load_modules.cpp
@@ -30,7 +30,7 @@ namespace fs = boost::filesystem;
 /***********************************************************************
  * Module Load Function
  **********************************************************************/
-#ifdef HAVE_DLFCN_H
+#if defined(HAVE_DLFCN_H)
 #include <dlfcn.h>
 static const std::string env_path_sep = ":";
 
@@ -42,7 +42,7 @@ static void load_module(const std::string &file_name){
     }
 }
 
-#elif HAVE_WINDOWS_H
+#elif defined(HAVE_WINDOWS_H)
 #include <windows.h>
 static const std::string env_path_sep = ";";
 
diff --git a/host/lib/sched.cpp b/host/lib/sched.cpp
deleted file mode 100644
index 712014c9c..000000000
--- a/host/lib/sched.cpp
+++ /dev/null
@@ -1,45 +0,0 @@
-//
-// Copyright 2010 Ettus Research LLC
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-//
-
-#include <uhd/utils/static.hpp>
-#include <stdexcept>
-#include <iostream>
-
-#ifdef HAVE_SCHED_H
-#include <sched.h>
-
-/*
- * # /etc/security/limits.conf
-#
-@usrp   -       rtprio  99
-*/
-
-UHD_STATIC_BLOCK(setup_process_sched){
-    try{
-        int policy = SCHED_RR;
-        int max_pri = sched_get_priority_max(policy);
-        if (max_pri == -1) throw std::runtime_error("sched_get_priority_max with SCHED_RR failed");
-        sched_param sp; sp.sched_priority = max_pri;
-        int ss_ret = sched_setscheduler(0, policy, &sp);
-        if (ss_ret == -1) throw std::runtime_error("sched_setscheduler with SCHED_RR failed");
-    }
-    catch(const std::exception &e){
-        std::cerr << "Process scheduling error: " << e.what() << std::endl;
-    }
-}
-
-#endif /* HAVE_SCHED_H */
diff --git a/host/lib/thread_priority.cpp b/host/lib/thread_priority.cpp
new file mode 100644
index 000000000..c35e5fcb1
--- /dev/null
+++ b/host/lib/thread_priority.cpp
@@ -0,0 +1,98 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/utils/thread_priority.hpp>
+#include <stdexcept>
+#include <iostream>
+
+bool uhd::set_thread_priority_safe(float priority, bool realtime){
+    try{
+        set_thread_priority(priority, realtime);
+        return true;
+    }catch(const std::exception &e){
+        std::cerr << "set_thread_priority: " << e.what() << std::endl;
+        return false;
+    }
+}
+
+static void check_priority_range(float priority){
+    if (priority > +1.0 or priority < -1.0)
+        throw std::range_error("priority out of range [-1.0, +1.0]");
+}
+
+/***********************************************************************
+ * Pthread API to set priority
+ **********************************************************************/
+#if defined(HAVE_PTHREAD_SETSCHEDPARAM)
+    #include <pthread.h>
+
+    void uhd::set_thread_priority(float priority, bool realtime){
+        check_priority_range(priority);
+
+        //when realtime is not enabled, use sched other
+        int policy = (realtime)? SCHED_RR : SCHED_OTHER;
+
+        //we cannot have below normal priority, set to zero
+        if (priority < 0) priority = 0;
+
+        //get the priority bounds for the selected policy
+        int min_pri = sched_get_priority_min(policy);
+        int max_pri = sched_get_priority_max(policy);
+        if (min_pri == -1 or max_pri == -1) throw std::runtime_error("error in sched_get_priority_min/max");
+
+        //set the new priority and policy
+        sched_param sp;
+        sp.sched_priority = int(priority*(max_pri - min_pri)) + min_pri;
+        int ret = pthread_setschedparam(pthread_self(), policy, &sp);
+        if (ret != 0) throw std::runtime_error("error in pthread_setschedparam");
+    }
+
+/***********************************************************************
+ * Windows API to set priority
+ **********************************************************************/
+#elif defined(HAVE_WIN_SETTHREADPRIORITY)
+    #include <windows.h>
+
+    void uhd::set_thread_priority(float priority, bool realtime){
+        check_priority_range(priority);
+
+        //set the priority class on the process
+        int pri_class = (realtime)? REALTIME_PRIORITY_CLASS : NORMAL_PRIORITY_CLASS;
+        if (SetPriorityClass(GetCurrentProcess(), pri_class) == 0)
+            throw std::runtime_error("error in SetPriorityClass");
+
+        //scale the priority value to the constants
+        int priorities[] = {
+            THREAD_PRIORITY_IDLE, THREAD_PRIORITY_LOWEST, THREAD_PRIORITY_BELOW_NORMAL, THREAD_PRIORITY_NORMAL,
+            THREAD_PRIORITY_ABOVE_NORMAL, THREAD_PRIORITY_HIGHEST, THREAD_PRIORITY_TIME_CRITICAL
+        };
+        size_t pri_index = size_t((priority+1.0)*6/2.0); // -1 -> 0, +1 -> 6
+
+        //set the thread priority on the thread
+        if (SetThreadPriority(GetCurrentThread(), priorities[pri_index]) == 0)
+            throw std::runtime_error("error in SetThreadPriority");
+    }
+
+/***********************************************************************
+ * Unimplemented API to set priority
+ **********************************************************************/
+#else
+    void uhd::set_thread_priority(float, bool){
+        throw std::runtime_error("set thread priority not implemented");
+    }
+
+#endif /* HAVE_PTHREAD_SETSCHEDPARAM */
diff --git a/host/lib/transport/if_addrs.cpp b/host/lib/transport/if_addrs.cpp
index 5c8c8a176..ad9a2325b 100644
--- a/host/lib/transport/if_addrs.cpp
+++ b/host/lib/transport/if_addrs.cpp
@@ -27,7 +27,7 @@ uhd::transport::if_addrs_t::if_addrs_t(void){
 /***********************************************************************
  * Interface address discovery through ifaddrs api
  **********************************************************************/
-#ifdef HAVE_IFADDRS_H
+#if defined(HAVE_IFADDRS_H)
 #include <ifaddrs.h>
 
 static boost::asio::ip::address_v4 sockaddr_to_ip_addr(sockaddr *addr){
@@ -59,9 +59,9 @@ std::vector<uhd::transport::if_addrs_t> uhd::transport::get_if_addrs(void){
 }
 
 /***********************************************************************
- * Interface address discovery through windows api (TODO)
+ * Interface address discovery through windows api
  **********************************************************************/
-#elif HAVE_WINSOCK2_H
+#elif defined(HAVE_WINSOCK2_H)
 #include <winsock2.h>
 
 std::vector<uhd::transport::if_addrs_t> uhd::transport::get_if_addrs(void){
diff --git a/host/lib/usrp/dboard/CMakeLists.txt b/host/lib/usrp/dboard/CMakeLists.txt
index 3a6c2d84a..6093583d3 100644
--- a/host/lib/usrp/dboard/CMakeLists.txt
+++ b/host/lib/usrp/dboard/CMakeLists.txt
@@ -22,5 +22,6 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_rfx.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_xcvr2450.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_wbx.cpp
+    ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_unknown.cpp
 )
 
diff --git a/host/lib/usrp/dboard/db_rfx.cpp b/host/lib/usrp/dboard/db_rfx.cpp
index 2585dfa8d..2d6088983 100644
--- a/host/lib/usrp/dboard/db_rfx.cpp
+++ b/host/lib/usrp/dboard/db_rfx.cpp
@@ -137,25 +137,21 @@ static dboard_base::sptr make_rfx_flex1200(dboard_base::ctor_args_t args){
     return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(1150e6, 1450e6), true, true));
 }
 
+static dboard_base::sptr make_rfx_flex2200(dboard_base::ctor_args_t args){
+    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(2000e6, 2400e6), false, false));
+}
+
 static dboard_base::sptr make_rfx_flex2400(dboard_base::ctor_args_t args){
     return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(2300e6, 2900e6), false, false));
 }
 
 UHD_STATIC_BLOCK(reg_rfx_dboards){
-    dboard_manager::register_dboard(0x0024, &make_rfx_flex400, "Flex 400 Rx MIMO B");
-    dboard_manager::register_dboard(0x0028, &make_rfx_flex400, "Flex 400 Tx MIMO B");
-
-    dboard_manager::register_dboard(0x0025, &make_rfx_flex900, "Flex 900 Rx MIMO B");
-    dboard_manager::register_dboard(0x0029, &make_rfx_flex900, "Flex 900 Tx MIMO B");
-
-    dboard_manager::register_dboard(0x0034, &make_rfx_flex1800, "Flex 1800 Rx MIMO B");
-    dboard_manager::register_dboard(0x0035, &make_rfx_flex1800, "Flex 1800 Tx MIMO B");
-
-    dboard_manager::register_dboard(0x0026, &make_rfx_flex1200, "Flex 1200 Rx MIMO B");
-    dboard_manager::register_dboard(0x002a, &make_rfx_flex1200, "Flex 1200 Tx MIMO B");
-
-    dboard_manager::register_dboard(0x0027, &make_rfx_flex2400, "Flex 2400 Rx MIMO B");
-    dboard_manager::register_dboard(0x002b, &make_rfx_flex2400, "Flex 2400 Tx MIMO B");
+    dboard_manager::register_dboard(0x0024, 0x0028, &make_rfx_flex400,  "Flex 400 MIMO B");
+    dboard_manager::register_dboard(0x0025, 0x0029, &make_rfx_flex900,  "Flex 900 MIMO B");
+    dboard_manager::register_dboard(0x0034, 0x0035, &make_rfx_flex1800, "Flex 1800 MIMO B");
+    dboard_manager::register_dboard(0x0026, 0x002a, &make_rfx_flex1200, "Flex 1200 MIMO B");
+    dboard_manager::register_dboard(0x002c, 0x002d, &make_rfx_flex2200, "Flex 2200 MIMO B");
+    dboard_manager::register_dboard(0x0027, 0x002b, &make_rfx_flex2400, "Flex 2400 MIMO B");
 }
 
 /***********************************************************************
@@ -257,7 +253,7 @@ void rfx_xcvr::set_rx_gain(float gain, const std::string &name){
         _rx_gains[name] = gain;
 
         //write the new voltage to the aux dac
-        this->get_iface()->write_aux_dac(dboard_iface::UNIT_RX, 0, dac_volts);
+        this->get_iface()->write_aux_dac(dboard_iface::UNIT_RX, dboard_iface::AUX_DAC_A, dac_volts);
     }
     else UHD_THROW_INVALID_CODE_PATH();
 }
diff --git a/host/lib/usrp/dboard/db_unknown.cpp b/host/lib/usrp/dboard/db_unknown.cpp
new file mode 100644
index 000000000..ced27e34d
--- /dev/null
+++ b/host/lib/usrp/dboard/db_unknown.cpp
@@ -0,0 +1,265 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/usrp/subdev_props.hpp>
+#include <uhd/types/ranges.hpp>
+#include <uhd/utils/assert.hpp>
+#include <uhd/utils/static.hpp>
+#include <uhd/usrp/dboard_base.hpp>
+#include <uhd/usrp/dboard_manager.hpp>
+#include <boost/assign/list_of.hpp>
+#include <boost/format.hpp>
+
+using namespace uhd;
+using namespace uhd::usrp;
+using namespace boost::assign;
+
+/***********************************************************************
+ * The unknown boards:
+ *   Like a basic board, but with only one subdev.
+ **********************************************************************/
+class unknown_rx : public rx_dboard_base{
+public:
+    unknown_rx(ctor_args_t args);
+    ~unknown_rx(void);
+
+    void rx_get(const wax::obj &key, wax::obj &val);
+    void rx_set(const wax::obj &key, const wax::obj &val);
+};
+
+class unknown_tx : public tx_dboard_base{
+public:
+    unknown_tx(ctor_args_t args);
+    ~unknown_tx(void);
+
+    void tx_get(const wax::obj &key, wax::obj &val);
+    void tx_set(const wax::obj &key, const wax::obj &val);
+};
+
+/***********************************************************************
+ * Register the unknown dboards
+ **********************************************************************/
+static dboard_base::sptr make_unknown_rx(dboard_base::ctor_args_t args){
+    return dboard_base::sptr(new unknown_rx(args));
+}
+
+static dboard_base::sptr make_unknown_tx(dboard_base::ctor_args_t args){
+    return dboard_base::sptr(new unknown_tx(args));
+}
+
+UHD_STATIC_BLOCK(reg_unknown_dboards){
+    dboard_manager::register_dboard(0xfff0, &make_unknown_tx, "Unknown TX");
+    dboard_manager::register_dboard(0xfff1, &make_unknown_rx, "Unknown RX");
+}
+
+/***********************************************************************
+ * Unknown RX dboard
+ **********************************************************************/
+unknown_rx::unknown_rx(ctor_args_t args) : rx_dboard_base(args){
+    /* NOP */
+}
+
+unknown_rx::~unknown_rx(void){
+    /* NOP */
+}
+
+void unknown_rx::rx_get(const wax::obj &key_, wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+    case SUBDEV_PROP_NAME:
+        val = "Unknown - " + get_rx_id().to_pp_string();
+        return;
+
+    case SUBDEV_PROP_OTHERS:
+        val = prop_names_t(); //empty
+        return;
+
+    case SUBDEV_PROP_GAIN:
+        val = float(0);
+        return;
+
+    case SUBDEV_PROP_GAIN_RANGE:
+        val = gain_range_t(0, 0, 0);
+        return;
+
+    case SUBDEV_PROP_GAIN_NAMES:
+        val = prop_names_t(); //empty
+        return;
+
+    case SUBDEV_PROP_FREQ:
+        val = double(0);
+        return;
+
+    case SUBDEV_PROP_FREQ_RANGE:
+        val = freq_range_t(0, 0);
+        return;
+
+    case SUBDEV_PROP_ANTENNA:
+        val = std::string("");
+        return;
+
+    case SUBDEV_PROP_ANTENNA_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
+    case SUBDEV_PROP_QUADRATURE:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_IQ_SWAPPED:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_SPECTRUM_INVERTED:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_USE_LO_OFFSET:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_LO_LOCKED:
+        val = true; //there is no LO, so it must be true!
+        return;
+
+    default: UHD_THROW_PROP_GET_ERROR();
+    }
+}
+
+void unknown_rx::rx_set(const wax::obj &key_, const wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+
+    case SUBDEV_PROP_GAIN:
+        UHD_ASSERT_THROW(val.as<float>() == float(0));
+        return;
+
+    case SUBDEV_PROP_ANTENNA:
+        UHD_ASSERT_THROW(val.as<std::string>() == std::string(""));
+        return;
+
+    case SUBDEV_PROP_FREQ:
+        return; // it wont do you much good, but you can set it
+
+    default: UHD_THROW_PROP_SET_ERROR();
+    }
+}
+
+/***********************************************************************
+ * Basic and LF TX dboard
+ **********************************************************************/
+unknown_tx::unknown_tx(ctor_args_t args) : tx_dboard_base(args){
+    /* NOP */
+}
+
+unknown_tx::~unknown_tx(void){
+    /* NOP */
+}
+
+void unknown_tx::tx_get(const wax::obj &key_, wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+    case SUBDEV_PROP_NAME:
+        val = "Unknown - " + get_tx_id().to_pp_string();
+        return;
+
+    case SUBDEV_PROP_OTHERS:
+        val = prop_names_t(); //empty
+        return;
+
+    case SUBDEV_PROP_GAIN:
+        val = float(0);
+        return;
+
+    case SUBDEV_PROP_GAIN_RANGE:
+        val = gain_range_t(0, 0, 0);
+        return;
+
+    case SUBDEV_PROP_GAIN_NAMES:
+        val = prop_names_t(); //empty
+        return;
+
+    case SUBDEV_PROP_FREQ:
+        val = double(0);
+        return;
+
+    case SUBDEV_PROP_FREQ_RANGE:
+        val = freq_range_t(0, 0);
+        return;
+
+    case SUBDEV_PROP_ANTENNA:
+        val = std::string("");
+        return;
+
+    case SUBDEV_PROP_ANTENNA_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
+    case SUBDEV_PROP_QUADRATURE:
+        val = true;
+        return;
+
+    case SUBDEV_PROP_IQ_SWAPPED:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_SPECTRUM_INVERTED:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_USE_LO_OFFSET:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_LO_LOCKED:
+        val = true; //there is no LO, so it must be true!
+        return;
+
+    default: UHD_THROW_PROP_GET_ERROR();
+    }
+}
+
+void unknown_tx::tx_set(const wax::obj &key_, const wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+
+    case SUBDEV_PROP_GAIN:
+        UHD_ASSERT_THROW(val.as<float>() == float(0));
+        return;
+
+    case SUBDEV_PROP_ANTENNA:
+        UHD_ASSERT_THROW(val.as<std::string>() == std::string(""));
+        return;
+
+    case SUBDEV_PROP_FREQ:
+        return; // it wont do you much good, but you can set it
+
+    default: UHD_THROW_PROP_SET_ERROR();
+    }
+}
diff --git a/host/lib/usrp/dboard/db_wbx.cpp b/host/lib/usrp/dboard/db_wbx.cpp
index 95dcb3802..2b2822b6b 100644
--- a/host/lib/usrp/dboard/db_wbx.cpp
+++ b/host/lib/usrp/dboard/db_wbx.cpp
@@ -154,8 +154,7 @@ static dboard_base::sptr make_wbx(dboard_base::ctor_args_t args){
 }
 
 UHD_STATIC_BLOCK(reg_wbx_dboards){
-    dboard_manager::register_dboard(0x0052, &make_wbx, "WBX RX");
-    dboard_manager::register_dboard(0x0053, &make_wbx, "WBX TX");
+    dboard_manager::register_dboard(0x0052, 0x0053, &make_wbx, "WBX");
 }
 
 /***********************************************************************
@@ -246,7 +245,7 @@ void wbx_xcvr::set_tx_gain(float gain, const std::string &name){
         _tx_gains[name] = gain;
 
         //write the new voltage to the aux dac
-        this->get_iface()->write_aux_dac(dboard_iface::UNIT_TX, 0, dac_volts);
+        this->get_iface()->write_aux_dac(dboard_iface::UNIT_TX, dboard_iface::AUX_DAC_A, dac_volts);
     }
     else UHD_THROW_INVALID_CODE_PATH();
 }
diff --git a/host/lib/usrp/dboard/db_xcvr2450.cpp b/host/lib/usrp/dboard/db_xcvr2450.cpp
index 974a378bd..5032b6f31 100644
--- a/host/lib/usrp/dboard/db_xcvr2450.cpp
+++ b/host/lib/usrp/dboard/db_xcvr2450.cpp
@@ -144,7 +144,7 @@ private:
         static const float min_v = float(0.5), max_v = float(2.5);
         static const float rssi_dyn_range = 60;
         //calculate the rssi from the voltage
-        float voltage = this->get_iface()->read_aux_adc(dboard_iface::UNIT_RX, 1);
+        float voltage = this->get_iface()->read_aux_adc(dboard_iface::UNIT_RX, dboard_iface::AUX_ADC_B);
         return rssi_dyn_range*(voltage - min_v)/(max_v - min_v);
     }
 };
@@ -158,8 +158,7 @@ static dboard_base::sptr make_xcvr2450(dboard_base::ctor_args_t args){
 
 UHD_STATIC_BLOCK(reg_xcvr2450_dboard){
     //register the factory function for the rx and tx dbids
-    dboard_manager::register_dboard(0x0060, &make_xcvr2450, "XCVR2450 TX");
-    dboard_manager::register_dboard(0x0061, &make_xcvr2450, "XCVR2450 RX");
+    dboard_manager::register_dboard(0x0061, 0x0060, &make_xcvr2450, "XCVR2450");
 }
 
 /***********************************************************************
diff --git a/host/lib/usrp/dboard_manager.cpp b/host/lib/usrp/dboard_manager.cpp
index 35ddfc4ee..6321e018f 100644
--- a/host/lib/usrp/dboard_manager.cpp
+++ b/host/lib/usrp/dboard_manager.cpp
@@ -43,7 +43,7 @@ typedef uhd::dict<dboard_id_t, args_t> id_to_args_map_t;
 UHD_SINGLETON_FCN(id_to_args_map_t, get_id_to_args_map)
 
 void dboard_manager::register_dboard(
-    dboard_id_t dboard_id,
+    const dboard_id_t &dboard_id,
     dboard_ctor_t dboard_ctor,
     const std::string &name,
     const prop_names_t &subdev_names
@@ -57,6 +57,26 @@ void dboard_manager::register_dboard(
     get_id_to_args_map()[dboard_id] = args_t(dboard_ctor, name, subdev_names);
 }
 
+//map an xcvr dboard id to its partner dboard id
+typedef uhd::dict<dboard_id_t, dboard_id_t> xcvr_id_to_id_map_t;
+UHD_SINGLETON_FCN(xcvr_id_to_id_map_t, get_xcvr_id_to_id_map)
+
+void dboard_manager::register_dboard(
+    const dboard_id_t &rx_dboard_id,
+    const dboard_id_t &tx_dboard_id,
+    dboard_ctor_t dboard_ctor,
+    const std::string &name,
+    const prop_names_t &subdev_names
+){
+    //regular registration for ids
+    register_dboard(rx_dboard_id, dboard_ctor, name + " RX", subdev_names);
+    register_dboard(tx_dboard_id, dboard_ctor, name + " TX", subdev_names);
+
+    //register xcvr mapping for ids
+    get_xcvr_id_to_id_map()[rx_dboard_id] = tx_dboard_id;
+    get_xcvr_id_to_id_map()[tx_dboard_id] = rx_dboard_id;
+}
+
 std::string dboard_id_t::to_pp_string(void) const{
     std::string name = "unknown";
     if (get_id_to_args_map().has_key(*this)){
@@ -168,26 +188,27 @@ dboard_manager::sptr dboard_manager::make(
  **********************************************************************/
 static args_t get_dboard_args(
     dboard_iface::unit_t unit,
-    dboard_id_t dboard_id
+    dboard_id_t dboard_id,
+    bool force_to_unknown = false
 ){
     //special case, the none id was provided, use the following ids
-    if (dboard_id == dboard_id_t::none()){
+    if (dboard_id == dboard_id_t::none() or force_to_unknown){
         std::cerr << boost::format(
-            "Warning: unregistered dboard id: %s"
-            " -> defaulting to a basic board"
+            "Warning: unknown dboard-id or dboard-id combination: %s\n"
+            "    -> defaulting to the unknown board type"
         ) % dboard_id.to_pp_string() << std::endl;
-        UHD_ASSERT_THROW(get_id_to_args_map().has_key(0x0001));
-        UHD_ASSERT_THROW(get_id_to_args_map().has_key(0x0000));
+        UHD_ASSERT_THROW(get_id_to_args_map().has_key(0xfff1));
+        UHD_ASSERT_THROW(get_id_to_args_map().has_key(0xfff0));
         switch(unit){
-        case dboard_iface::UNIT_RX: return get_dboard_args(unit, 0x0001);
-        case dboard_iface::UNIT_TX: return get_dboard_args(unit, 0x0000);
+        case dboard_iface::UNIT_RX: return get_dboard_args(unit, 0xfff1);
+        case dboard_iface::UNIT_TX: return get_dboard_args(unit, 0xfff0);
         default: UHD_THROW_INVALID_CODE_PATH();
         }
     }
 
     //verify that there is a registered constructor for this id
     if (not get_id_to_args_map().has_key(dboard_id)){
-        return get_dboard_args(unit, dboard_id_t::none());
+        return get_dboard_args(unit, dboard_id, true);
     }
 
     //return the dboard args for this id
@@ -201,11 +222,21 @@ dboard_manager_impl::dboard_manager_impl(
 ){
     _iface = iface;
 
+    //determine xcvr status
+    bool rx_dboard_is_xcvr = get_xcvr_id_to_id_map().has_key(rx_dboard_id);
+    bool tx_dboard_is_xcvr = get_xcvr_id_to_id_map().has_key(tx_dboard_id);
+    bool this_dboard_is_xcvr = (
+        rx_dboard_is_xcvr and tx_dboard_is_xcvr and
+        (get_xcvr_id_to_id_map()[rx_dboard_id] == tx_dboard_id) and
+        (get_xcvr_id_to_id_map()[tx_dboard_id] == rx_dboard_id)
+    );
+
+    //extract dboard constructor and settings (force to unknown for messed up xcvr status)
     dboard_ctor_t rx_dboard_ctor; std::string rx_name; prop_names_t rx_subdevs;
-    boost::tie(rx_dboard_ctor, rx_name, rx_subdevs) = get_dboard_args(dboard_iface::UNIT_RX, rx_dboard_id);
+    boost::tie(rx_dboard_ctor, rx_name, rx_subdevs) = get_dboard_args(dboard_iface::UNIT_RX, rx_dboard_id, rx_dboard_is_xcvr != this_dboard_is_xcvr);
 
     dboard_ctor_t tx_dboard_ctor; std::string tx_name; prop_names_t tx_subdevs;
-    boost::tie(tx_dboard_ctor, tx_name, tx_subdevs) = get_dboard_args(dboard_iface::UNIT_TX, tx_dboard_id);
+    boost::tie(tx_dboard_ctor, tx_name, tx_subdevs) = get_dboard_args(dboard_iface::UNIT_TX, tx_dboard_id, tx_dboard_is_xcvr != this_dboard_is_xcvr);
 
     //initialize the gpio pins before creating subdevs
     set_nice_dboard_if();
@@ -215,7 +246,8 @@ dboard_manager_impl::dboard_manager_impl(
     db_ctor_args.db_iface = iface;
 
     //make xcvr subdevs (make one subdev for both rx and tx dboards)
-    if (rx_dboard_ctor == tx_dboard_ctor){
+    if (this_dboard_is_xcvr){
+        UHD_ASSERT_THROW(rx_dboard_ctor == tx_dboard_ctor);
         UHD_ASSERT_THROW(rx_subdevs == tx_subdevs);
         BOOST_FOREACH(const std::string &subdev, rx_subdevs){
             db_ctor_args.sd_name = subdev;
diff --git a/host/lib/usrp/usrp2/clock_ctrl.cpp b/host/lib/usrp/usrp2/clock_ctrl.cpp
index d9baa66cf..b9be037c0 100644
--- a/host/lib/usrp/usrp2/clock_ctrl.cpp
+++ b/host/lib/usrp/usrp2/clock_ctrl.cpp
@@ -18,6 +18,7 @@
 #include "clock_ctrl.hpp"
 #include "ad9510_regs.hpp"
 #include "usrp2_regs.hpp" //spi slave constants
+#include <uhd/utils/assert.hpp>
 #include <boost/cstdint.hpp>
 
 using namespace uhd;
@@ -79,23 +80,63 @@ public:
         _ad9510_regs.power_down_lvds_cmos_out7 = enb? 0 : 1;
         _ad9510_regs.lvds_cmos_select_out7 = ad9510_regs_t::LVDS_CMOS_SELECT_OUT7_CMOS;
         _ad9510_regs.output_level_lvds_out7 = ad9510_regs_t::OUTPUT_LEVEL_LVDS_OUT7_1_75MA;
-        _ad9510_regs.bypass_divider_out7 = 1;
         this->write_reg(0x43);
+        this->update_regs();
+    }
+
+    void set_rate_rx_dboard_clock(double rate){
+        assert_has(get_rates_rx_dboard_clock(), rate, "rx dboard clock rate");
+        size_t divider = size_t(rate/get_master_clock_rate());
+        //bypass when the divider ratio is one
+        _ad9510_regs.bypass_divider_out7 = (divider == 1)? 1 : 0;
+        //calculate the low and high dividers
+        size_t high = divider/2;
+        size_t low = divider - high;
+        //set the registers (divider - 1)
+        _ad9510_regs.divider_low_cycles_out7 = low - 1;
+        _ad9510_regs.divider_high_cycles_out7 = high - 1;
+        //write the registers
+        this->write_reg(0x56);
         this->write_reg(0x57);
         this->update_regs();
     }
 
+    std::vector<double> get_rates_rx_dboard_clock(void){
+        std::vector<double> rates;
+        for (size_t i = 1; i <= 16+16; i++) rates.push_back(get_master_clock_rate()/i);
+        return rates;
+    }
+
     //uses output clock 6 (cmos)
     void enable_tx_dboard_clock(bool enb){
         _ad9510_regs.power_down_lvds_cmos_out6 = enb? 0 : 1;
         _ad9510_regs.lvds_cmos_select_out6 = ad9510_regs_t::LVDS_CMOS_SELECT_OUT6_CMOS;
         _ad9510_regs.output_level_lvds_out6 = ad9510_regs_t::OUTPUT_LEVEL_LVDS_OUT6_1_75MA;
-        _ad9510_regs.bypass_divider_out6 = 1;
         this->write_reg(0x42);
+        this->update_regs();
+    }
+
+    void set_rate_tx_dboard_clock(double rate){
+        assert_has(get_rates_tx_dboard_clock(), rate, "tx dboard clock rate");
+        size_t divider = size_t(rate/get_master_clock_rate());
+        //bypass when the divider ratio is one
+        _ad9510_regs.bypass_divider_out6 = (divider == 1)? 1 : 0;
+        //calculate the low and high dividers
+        size_t high = divider/2;
+        size_t low = divider - high;
+        //set the registers (divider - 1)
+        _ad9510_regs.divider_low_cycles_out6 = low - 1;
+        _ad9510_regs.divider_high_cycles_out6 = high - 1;
+        //write the registers
+        this->write_reg(0x54);
         this->write_reg(0x55);
         this->update_regs();
     }
 
+    std::vector<double> get_rates_tx_dboard_clock(void){
+        return get_rates_rx_dboard_clock(); //same master clock, same dividers...
+    }
+
     /*!
      * If we are to use an external reference, enable the charge pump.
      * \param enb true to enable the CP
diff --git a/host/lib/usrp/usrp2/clock_ctrl.hpp b/host/lib/usrp/usrp2/clock_ctrl.hpp
index 0ad8d9532..70a104a81 100644
--- a/host/lib/usrp/usrp2/clock_ctrl.hpp
+++ b/host/lib/usrp/usrp2/clock_ctrl.hpp
@@ -21,6 +21,7 @@
 #include "usrp2_iface.hpp"
 #include <boost/shared_ptr.hpp>
 #include <boost/utility.hpp>
+#include <vector>
 
 class usrp2_clock_ctrl : boost::noncopyable{
 public:
@@ -46,12 +47,38 @@ public:
     virtual void enable_rx_dboard_clock(bool enb) = 0;
 
     /*!
+     * Set the clock rate on the rx dboard clock.
+     * \param rate the new clock rate
+     * \throw exception when rate invalid
+     */
+    virtual void set_rate_rx_dboard_clock(double rate) = 0;
+
+    /*!
+     * Get a list of possible rx dboard clock rates.
+     * \return a list of clock rates in Hz
+     */
+    virtual std::vector<double> get_rates_rx_dboard_clock(void) = 0;
+
+    /*!
      * Enable/disable the tx dboard clock.
      * \param enb true to enable
      */
     virtual void enable_tx_dboard_clock(bool enb) = 0;
 
     /*!
+     * Set the clock rate on the tx dboard clock.
+     * \param rate the new clock rate
+     * \throw exception when rate invalid
+     */
+    virtual void set_rate_tx_dboard_clock(double rate) = 0;
+
+    /*!
+     * Get a list of possible tx dboard clock rates.
+     * \return a list of clock rates in Hz
+     */
+    virtual std::vector<double> get_rates_tx_dboard_clock(void) = 0;
+
+    /*!
      * Enable/disable external reference.
      * \param enb true to enable
      */
diff --git a/host/lib/usrp/usrp2/dboard_iface.cpp b/host/lib/usrp/usrp2/dboard_iface.cpp
index 114f83f41..6f2fb9396 100644
--- a/host/lib/usrp/usrp2/dboard_iface.cpp
+++ b/host/lib/usrp/usrp2/dboard_iface.cpp
@@ -21,6 +21,7 @@
 #include <uhd/usrp/dboard_iface.hpp>
 #include <uhd/types/dict.hpp>
 #include <uhd/utils/assert.hpp>
+#include <uhd/utils/algorithm.hpp>
 #include <boost/assign/list_of.hpp>
 #include <boost/asio.hpp> //htonl and ntohl
 #include <boost/math/special_functions/round.hpp>
@@ -36,8 +37,8 @@ public:
     usrp2_dboard_iface(usrp2_iface::sptr iface, usrp2_clock_ctrl::sptr clock_ctrl);
     ~usrp2_dboard_iface(void);
 
-    void write_aux_dac(unit_t, int, float);
-    float read_aux_adc(unit_t, int);
+    void write_aux_dac(unit_t, aux_dac_t, float);
+    float read_aux_adc(unit_t, aux_adc_t);
 
     void set_pin_ctrl(unit_t, boost::uint16_t);
     void set_atr_reg(unit_t, atr_reg_t, boost::uint16_t);
@@ -48,9 +49,10 @@ public:
     void write_i2c(boost::uint8_t, const byte_vector_t &);
     byte_vector_t read_i2c(boost::uint8_t, size_t);
 
+    void set_clock_rate(unit_t, double);
     double get_clock_rate(unit_t);
+    std::vector<double> get_clock_rates(unit_t);
     void set_clock_enabled(unit_t, bool);
-    bool get_clock_enabled(unit_t);
 
     void write_spi(
         unit_t unit,
@@ -73,6 +75,7 @@ private:
     boost::uint32_t _gpio_shadow;
 
     uhd::dict<unit_t, ad5623_regs_t> _dac_regs;
+    uhd::dict<unit_t, double> _clock_rates;
     void _write_aux_dac(unit_t);
 };
 
@@ -107,6 +110,10 @@ usrp2_dboard_iface::usrp2_dboard_iface(
         _dac_regs[unit].cmd  = ad5623_regs_t::CMD_RESET;
         this->_write_aux_dac(unit);
     }
+
+    //init the clock rate shadows with max rate clock
+    this->set_clock_rate(UNIT_RX, sorted(this->get_clock_rates(UNIT_RX)).back());
+    this->set_clock_rate(UNIT_TX, sorted(this->get_clock_rates(UNIT_TX)).back());
 }
 
 usrp2_dboard_iface::~usrp2_dboard_iface(void){
@@ -116,8 +123,24 @@ usrp2_dboard_iface::~usrp2_dboard_iface(void){
 /***********************************************************************
  * Clocks
  **********************************************************************/
-double usrp2_dboard_iface::get_clock_rate(unit_t){
-    return _clock_ctrl->get_master_clock_rate();
+void usrp2_dboard_iface::set_clock_rate(unit_t unit, double rate){
+    _clock_rates[unit] = rate; //set to shadow
+    switch(unit){
+    case UNIT_RX: _clock_ctrl->set_rate_rx_dboard_clock(rate); return;
+    case UNIT_TX: _clock_ctrl->set_rate_tx_dboard_clock(rate); return;
+    }
+}
+
+double usrp2_dboard_iface::get_clock_rate(unit_t unit){
+    return _clock_rates[unit]; //get from shadow
+}
+
+std::vector<double> usrp2_dboard_iface::get_clock_rates(unit_t unit){
+    switch(unit){
+    case UNIT_RX: return _clock_ctrl->get_rates_rx_dboard_clock();
+    case UNIT_TX: return _clock_ctrl->get_rates_tx_dboard_clock();
+    default: UHD_THROW_INVALID_CODE_PATH();
+    }
 }
 
 void usrp2_dboard_iface::set_clock_enabled(unit_t unit, bool enb){
@@ -240,31 +263,30 @@ void usrp2_dboard_iface::_write_aux_dac(unit_t unit){
     );
 }
 
-void usrp2_dboard_iface::write_aux_dac(unit_t unit, int which, float value){
+void usrp2_dboard_iface::write_aux_dac(unit_t unit, aux_dac_t which, float value){
     _dac_regs[unit].data = boost::math::iround(4095*value/3.3);
     _dac_regs[unit].cmd = ad5623_regs_t::CMD_WR_UP_DAC_CHAN_N;
-    //standardize on USRP1 interface, A=0, B=1, C=2, D=3
-    static const uhd::dict<
-        unit_t, uhd::dict<int, ad5623_regs_t::addr_t>
-    > unit_to_which_to_addr = map_list_of
+
+    typedef uhd::dict<aux_dac_t, ad5623_regs_t::addr_t> aux_dac_to_addr;
+    static const uhd::dict<unit_t, aux_dac_to_addr> unit_to_which_to_addr = map_list_of
         (UNIT_RX, map_list_of
-            (0, ad5623_regs_t::ADDR_DAC_B)
-            (1, ad5623_regs_t::ADDR_DAC_A)
-            (2, ad5623_regs_t::ADDR_DAC_A)
-            (3, ad5623_regs_t::ADDR_DAC_B)
+            (AUX_DAC_A, ad5623_regs_t::ADDR_DAC_B)
+            (AUX_DAC_B, ad5623_regs_t::ADDR_DAC_A)
+            (AUX_DAC_C, ad5623_regs_t::ADDR_DAC_A)
+            (AUX_DAC_D, ad5623_regs_t::ADDR_DAC_B)
         )
         (UNIT_TX, map_list_of
-            (0, ad5623_regs_t::ADDR_DAC_A)
-            (1, ad5623_regs_t::ADDR_DAC_B)
-            (2, ad5623_regs_t::ADDR_DAC_B)
-            (3, ad5623_regs_t::ADDR_DAC_A)
+            (AUX_DAC_A, ad5623_regs_t::ADDR_DAC_A)
+            (AUX_DAC_B, ad5623_regs_t::ADDR_DAC_B)
+            (AUX_DAC_C, ad5623_regs_t::ADDR_DAC_B)
+            (AUX_DAC_D, ad5623_regs_t::ADDR_DAC_A)
         )
     ;
     _dac_regs[unit].addr = unit_to_which_to_addr[unit][which];
     this->_write_aux_dac(unit);
 }
 
-float usrp2_dboard_iface::read_aux_adc(unit_t unit, int which){
+float usrp2_dboard_iface::read_aux_adc(unit_t unit, aux_adc_t which){
     static const uhd::dict<unit_t, int> unit_to_spi_adc = map_list_of
         (UNIT_RX, SPI_SS_RX_ADC)
         (UNIT_TX, SPI_SS_TX_ADC)
@@ -277,8 +299,10 @@ float usrp2_dboard_iface::read_aux_adc(unit_t unit, int which){
 
     //setup the spi registers
     ad7922_regs_t ad7922_regs;
-    ad7922_regs.mod = which; //normal mode: mod == chn
-    ad7922_regs.chn = which;
+    switch(which){
+    case AUX_ADC_A: ad7922_regs.mod = 0; break;
+    case AUX_ADC_B: ad7922_regs.mod = 1; break;
+    } ad7922_regs.chn = ad7922_regs.mod; //normal mode: mod == chn
 
     //write and read spi
     _iface->transact_spi(
diff --git a/host/lib/usrp/usrp2/fw_common.h b/host/lib/usrp/usrp2/fw_common.h
index 75f5b1779..242d268ec 100644
--- a/host/lib/usrp/usrp2/fw_common.h
+++ b/host/lib/usrp/usrp2/fw_common.h
@@ -32,9 +32,13 @@ extern "C" {
 #define _SINS_
 #endif
 
+// define limits on bytes per udp packet
+#define USRP2_MTU_BYTES 1500
+#define USRP2_UDP_BYTES ((USRP2_MTU_BYTES) - (2 + 14 + 20 + 8)) //size of headers (pad, eth, ip, udp)
+
 //defines the protocol version in this shared header
 //increment this value when the protocol is changed
-#define USRP2_PROTO_VERSION 3
+#define USRP2_PROTO_VERSION 4
 
 //used to differentiate control packets over data port
 #define USRP2_INVALID_VRT_HEADER 0
@@ -102,7 +106,7 @@ typedef struct{
         struct {
             _SINS_ uint8_t addr;
             _SINS_ uint8_t bytes;
-            _SINS_ uint8_t data[sizeof(_SINS_ uint32_t)];
+            _SINS_ uint8_t data[20];
         } i2c_args;
         struct {
             _SINS_ uint32_t addr;
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index 6cb2a735b..aa0f63321 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -18,6 +18,7 @@
 #include "../../transport/vrt_packet_handler.hpp"
 #include "usrp2_impl.hpp"
 #include "usrp2_regs.hpp"
+#include <uhd/utils/thread_priority.hpp>
 #include <uhd/transport/convert_types.hpp>
 #include <uhd/transport/bounded_buffer.hpp>
 #include <boost/format.hpp>
@@ -78,6 +79,7 @@ managed_recv_buffer::sptr usrp2_impl::io_impl::get_recv_buff(void){
 }
 
 void usrp2_impl::io_impl::recv_pirate_loop(zero_copy_if::sptr zc_if){
+    set_thread_priority_safe();
     recv_pirate_running = true;
     while(recv_pirate_running){
         managed_recv_buffer::sptr buff = zc_if->get_recv_buff();
diff --git a/host/lib/usrp/usrp2/usrp2_iface.cpp b/host/lib/usrp/usrp2/usrp2_iface.cpp
index 6e0d3266a..83e98904e 100644
--- a/host/lib/usrp/usrp2/usrp2_iface.cpp
+++ b/host/lib/usrp/usrp2/usrp2_iface.cpp
@@ -146,7 +146,7 @@ public:
         _ctrl_transport->send(boost::asio::buffer(&out_copy, sizeof(usrp2_ctrl_data_t)));
 
         //loop until we get the packet or timeout
-        boost::uint8_t usrp2_ctrl_data_in_mem[1500]; //allocate MTU bytes for recv
+        boost::uint8_t usrp2_ctrl_data_in_mem[USRP2_UDP_BYTES]; //allocate max bytes for recv
         usrp2_ctrl_data_t *ctrl_data_in = reinterpret_cast<usrp2_ctrl_data_t *>(usrp2_ctrl_data_in_mem);
         while(true){
             size_t len = _ctrl_transport->recv(boost::asio::buffer(usrp2_ctrl_data_in_mem));
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index 0837f4ac4..36c264c3c 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -79,12 +79,12 @@ uhd::device_addrs_t usrp2::find(const device_addr_t &hint){
     udp_transport->send(boost::asio::buffer(&ctrl_data_out, sizeof(ctrl_data_out)));
 
     //loop and recieve until the timeout
-    boost::uint8_t usrp2_ctrl_data_in_mem[1500]; //allocate MTU bytes for recv
+    boost::uint8_t usrp2_ctrl_data_in_mem[USRP2_UDP_BYTES]; //allocate max bytes for recv
     usrp2_ctrl_data_t *ctrl_data_in = reinterpret_cast<usrp2_ctrl_data_t *>(usrp2_ctrl_data_in_mem);
     while(true){
         size_t len = udp_transport->recv(asio::buffer(usrp2_ctrl_data_in_mem));
         //std::cout << len << "\n";
-        if (len >= sizeof(usrp2_ctrl_data_t)){
+        if (len > offsetof(usrp2_ctrl_data_t, data)){
             //handle the received data
             switch(ntohl(ctrl_data_in->id)){
             case USRP2_CTRL_ID_WAZZUP_DUDE:
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index ccc09003e..2126b9565 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -141,15 +141,13 @@ private:
     /*******************************************************************
      * Deal with the rx and tx packet sizes
      ******************************************************************/
-    static const size_t _mtu = 1500; //FIXME we have no idea
-    static const size_t _hdrs = (2 + 14 + 20 + 8); //size of headers (pad, eth, ip, udp)
     static const size_t _max_rx_bytes_per_packet =
-        _mtu - _hdrs -
+        USRP2_UDP_BYTES -
         USRP2_HOST_RX_VRT_HEADER_WORDS32*sizeof(boost::uint32_t) -
         USRP2_HOST_RX_VRT_TRAILER_WORDS32*sizeof(boost::uint32_t)
     ;
     static const size_t _max_tx_bytes_per_packet =
-        _mtu - _hdrs -
+        USRP2_UDP_BYTES -
         uhd::transport::vrt::max_header_words32*sizeof(boost::uint32_t)
     ;