usrp: added to subdev spec comments/docs

1 files changed, 8 insertions, 3 deletions

diff --git a/host/include/uhd/usrp/subdev_spec.hpp b/host/include/uhd/usrp/subdev_spec.hpp
index 5de3bb3b8..b189724c9 100644
--- a/host/include/uhd/usrp/subdev_spec.hpp
+++ b/host/include/uhd/usrp/subdev_spec.hpp
@@ -26,10 +26,10 @@
 namespace uhd{ namespace usrp{
 
     /*!
-     * A subdevice specification (daughterboard, subdevice) name pairing.
+     * A subdevice specification (daughterboard slot, subdevice) name pairing.
      */
     struct UHD_API subdev_spec_pair_t : boost::equality_comparable<subdev_spec_pair_t>{
-        //! The daughterboard name
+        //! The daughterboard slot name
         std::string db_name;
 
         //! The subdevice name
@@ -50,7 +50,7 @@ namespace uhd{ namespace usrp{
     UHD_API bool operator==(const subdev_spec_pair_t &, const subdev_spec_pair_t &);
 
     /*!
-     * A list of (daughterboard name, subdevice name) pairs:
+     * A list of (daughterboard slot name, subdevice name) pairs:
      *
      * A subdevice specification represents a list of subdevices on a motherboard.
      * The subdevices specified may span across multiple daughterboards;
@@ -62,6 +62,11 @@ namespace uhd{ namespace usrp{
      * The markup-string is a whitespace separated list of dboard:subdev pairs.
      * The first pair represents the subdevice for channel zero,
      * the second pair represents the subdevice for channel one, and so on.
+     *
+     * Special handling for empty conditions:
+     * - An empty subdevice specification means: select the first subdevice found in the configuration
+     * - An empty daughterboard name means: select the only daughterboard slot or error if multiple exist
+     * - An empty subdevice name means: select the only subdevice on that board or error if multiple exist
      */
     class UHD_API subdev_spec_t : public std::vector<subdev_spec_pair_t>{
     public: