3 files changed, 29 insertions, 22 deletions

diff --git a/host/lib/usrp/b200/b200_impl.cpp b/host/lib/usrp/b200/b200_impl.cpp
index f3307dc4d..de61db610 100644
--- a/host/lib/usrp/b200/b200_impl.cpp
+++ b/host/lib/usrp/b200/b200_impl.cpp
@@ -208,7 +208,8 @@ UHD_STATIC_BLOCK(register_b200_device)
  * Structors
  **********************************************************************/
 b200_impl::b200_impl(const device_addr_t &device_addr) :
-    _tick_rate(0.0) // Forces a clock initialization at startup
+    _tick_rate(0.0), // Forces a clock initialization at startup
+    _revision(0)
 {
     _tree = property_tree::make();
     _type = device::USRP;
@@ -305,6 +306,9 @@ b200_impl::b200_impl(const device_addr_t &device_addr) :
         product_name = "B200?";
         _b200_type = B200;
     }
+    if (not mb_eeprom["revision"].empty()) {
+        _revision = boost::lexical_cast<size_t>(mb_eeprom["revision"]);
+    }
 
     ////////////////////////////////////////////////////////////////////
     // Set up frontend mapping
@@ -323,13 +327,10 @@ b200_impl::b200_impl(const device_addr_t &device_addr) :
     _fe2 = 0;
     _gpio_state.swap_atr = 1;
     // Unswapped setup:
-    if (_b200_type == B200 and
-        not mb_eeprom["revision"].empty() and
-        boost::lexical_cast<size_t>(mb_eeprom["revision"]) >= 5)
-    {
+    if (_b200_type == B200 and _revision >= 5) {
         _fe1 = 0;                   //map radio0 to FE1
         _fe2 = 1;                   //map radio1 to FE2
-        _gpio_state.swap_atr = 0;    //map radio0 ATR pins to FE2
+        _gpio_state.swap_atr = 0; // ATRs for radio0 are mapped to FE1
     }
 
     ////////////////////////////////////////////////////////////////////
@@ -503,9 +504,11 @@ b200_impl::b200_impl(const device_addr_t &device_addr) :
     _tree->create<std::vector<size_t> >(mb_path / "rx_chan_dsp_mapping").set(default_map);
     _tree->create<std::vector<size_t> >(mb_path / "tx_chan_dsp_mapping").set(default_map);
     _tree->create<subdev_spec_t>(mb_path / "rx_subdev_spec")
+        .coerce(boost::bind(&b200_impl::coerce_subdev_spec, this, _1))
         .set(subdev_spec_t())
         .subscribe(boost::bind(&b200_impl::update_subdev_spec, this, "rx", _1));
     _tree->create<subdev_spec_t>(mb_path / "tx_subdev_spec")
+        .coerce(boost::bind(&b200_impl::coerce_subdev_spec, this, _1))
         .set(subdev_spec_t())
         .subscribe(boost::bind(&b200_impl::update_subdev_spec, this, "tx", _1));
 
diff --git a/host/lib/usrp/b200/b200_impl.hpp b/host/lib/usrp/b200/b200_impl.hpp
index 4dd45baee..f5a7b62e9 100644
--- a/host/lib/usrp/b200/b200_impl.hpp
+++ b/host/lib/usrp/b200/b200_impl.hpp
@@ -108,6 +108,7 @@ public:
 
 private:
     b200_type_t _b200_type;
+    size_t      _revision;
 
     //controllers
     b200_iface::sptr _iface;
@@ -145,6 +146,7 @@ private:
     void set_mb_eeprom(const uhd::usrp::mboard_eeprom_t &);
     void check_fw_compat(void);
     void check_fpga_compat(void);
+    uhd::usrp::subdev_spec_t coerce_subdev_spec(const uhd::usrp::subdev_spec_t &);
     void update_subdev_spec(const std::string &tx_rx, const uhd::usrp::subdev_spec_t &);
     void update_time_source(const std::string &);
     void update_clock_source(const std::string &);
diff --git a/host/lib/usrp/b200/b200_io_impl.cpp b/host/lib/usrp/b200/b200_io_impl.cpp
index 52a90a623..61bcc5f64 100644
--- a/host/lib/usrp/b200/b200_io_impl.cpp
+++ b/host/lib/usrp/b200/b200_io_impl.cpp
@@ -245,29 +245,31 @@ void b200_impl::update_tx_samp_rate(const size_t dspno, const double rate)
 /***********************************************************************
  * frontend selection
  **********************************************************************/
+uhd::usrp::subdev_spec_t b200_impl::coerce_subdev_spec(const uhd::usrp::subdev_spec_t &spec_)
+{
+    uhd::usrp::subdev_spec_t spec = spec_;
+    // Because of the confusing nature of the subdevs on B200
+    // with different revs, we provide a convenience override,
+    // where both A:A and A:B are mapped to A:A.
+    //
+    // Any other spec is probably illegal and will be caught by
+    // validate_subdev_spec().
+    if (spec.size() and _b200_type == B200 and spec[0].sd_name == "B") {
+        spec[0].sd_name = "A";
+    }
+    return spec;
+}
+
 void b200_impl::update_subdev_spec(const std::string &tx_rx, const uhd::usrp::subdev_spec_t &spec)
 {
     //sanity checking
-    if (spec.size()) validate_subdev_spec(_tree, spec, tx_rx);
-    UHD_ASSERT_THROW(spec.size() <= _radio_perifs.size());
-
-    if (spec.size() >= 1)
-    {
-        UHD_ASSERT_THROW(spec[0].db_name == "A");
-        UHD_ASSERT_THROW(spec[0].sd_name == "A" or spec[0].sd_name == "B");
-    }
-    if (spec.size() == 2)
-    {
-        UHD_ASSERT_THROW(spec[1].db_name == "A");
-        UHD_ASSERT_THROW(
-            (spec[0].sd_name == "A" and spec[1].sd_name == "B") or
-            (spec[0].sd_name == "B" and spec[1].sd_name == "A")
-        );
+    if (spec.size()) {
+        validate_subdev_spec(_tree, spec, tx_rx);
     }
 
     std::vector<size_t> chan_to_dsp_map(spec.size(), 0);
     for (size_t i = 0; i < spec.size(); i++) {
-	chan_to_dsp_map[i] = (spec[i].sd_name == "A") ? 0 : 1;
+        chan_to_dsp_map[i] = (spec[i].sd_name == "A") ? 0 : 1;
     }
     _tree->access<std::vector<size_t> >("/mboards/0" / (tx_rx + "_chan_dsp_mapping")).set(chan_to_dsp_map);