3 files changed, 30 insertions, 7 deletions
diff --git a/host/include/uhd/usrp/misc_utils.hpp b/host/include/uhd/usrp/misc_utils.hpp
index 14db80162..2af9f5b40 100644
--- a/host/include/uhd/usrp/misc_utils.hpp
+++ b/host/include/uhd/usrp/misc_utils.hpp
@@ -26,9 +26,23 @@
 namespace uhd{ namespace usrp{
 
     /*!
+     * Different policies for gain group prioritization.
+     */
+    enum gain_group_policy_t{
+        GAIN_GROUP_POLICY_RX = 'R',
+        GAIN_GROUP_POLICY_TX = 'T'
+    };
+
+    /*!
      * Create a gain group that represents the subdevice and its codec.
+     * \param subdev the object with subdevice properties
+     * \param codec the object with codec properties
+     * \param gain_group_policy the policy to use
      */
-    UHD_API gain_group::sptr make_gain_group(wax::obj subdev, wax::obj codec);
+    UHD_API gain_group::sptr make_gain_group(
+        wax::obj subdev, wax::obj codec,
+        gain_group_policy_t gain_group_policy
+    );
 
     /*!
      * Verify the rx subdevice specification.
diff --git a/host/lib/usrp/misc_utils.cpp b/host/lib/usrp/misc_utils.cpp
index 41239b144..46094ba32 100644
--- a/host/lib/usrp/misc_utils.cpp
+++ b/host/lib/usrp/misc_utils.cpp
@@ -29,9 +29,6 @@
 using namespace uhd;
 using namespace uhd::usrp;
 
-static const size_t subdev_gain_priority = 1; //higher, closer to the antenna
-static const size_t codec_gain_priority = 0;
-
 /***********************************************************************
  * codec gain group helper functions:
  *    do this so we dont have to bind a templated function
@@ -80,7 +77,15 @@ static void set_subdev_gain(wax::obj subdev, const std::string &name, float gain
 /***********************************************************************
  * gain group factory function for usrp
  **********************************************************************/
-gain_group::sptr usrp::make_gain_group(wax::obj subdev, wax::obj codec){
+gain_group::sptr usrp::make_gain_group(
+    wax::obj subdev, wax::obj codec,
+    gain_group_policy_t gain_group_policy
+){
+    const size_t subdev_gain_priority = 1;
+    const size_t codec_gain_priority = (gain_group_policy == GAIN_GROUP_POLICY_RX)?
+        (subdev_gain_priority - 1): //RX policy, codec gains fill last (lower priority)
+        (subdev_gain_priority + 1); //TX policy, codec gains fill first (higher priority)
+
     gain_group::sptr gg = gain_group::make();
     gain_fcns_t fcns;
     //add all the subdev gains first (antenna to dsp order)
diff --git a/host/lib/usrp/usrp2/dboard_impl.cpp b/host/lib/usrp/usrp2/dboard_impl.cpp
index 99599f11a..a462b93c2 100644
--- a/host/lib/usrp/usrp2/dboard_impl.cpp
+++ b/host/lib/usrp/usrp2/dboard_impl.cpp
@@ -89,7 +89,9 @@ void usrp2_mboard_impl::rx_dboard_get(const wax::obj &key_, wax::obj &val){
 
     case DBOARD_PROP_GAIN_GROUP:
         val = make_gain_group(
-            _dboard_manager->get_rx_subdev(key.name), _rx_codec_proxy->get_link()
+            _dboard_manager->get_rx_subdev(key.name),
+            _rx_codec_proxy->get_link(),
+            GAIN_GROUP_POLICY_RX
         );
         return;
 
@@ -143,7 +145,9 @@ void usrp2_mboard_impl::tx_dboard_get(const wax::obj &key_, wax::obj &val){
 
     case DBOARD_PROP_GAIN_GROUP:
         val = make_gain_group(
-            _dboard_manager->get_tx_subdev(key.name), _tx_codec_proxy->get_link()
+            _dboard_manager->get_tx_subdev(key.name),
+            _tx_codec_proxy->get_link(),
+            GAIN_GROUP_POLICY_TX
         );
         return;