usrp2: increased transport buffer minimum size, and added warning

added more notes on buffer size to the manual

pulled in some firmware fixes from the mimo work, just to have them in here

1 files changed, 8 insertions, 1 deletions

diff --git a/host/lib/transport/udp_zero_copy_asio.cpp b/host/lib/transport/udp_zero_copy_asio.cpp
index c3c02707e..7f9292d24 100644
--- a/host/lib/transport/udp_zero_copy_asio.cpp
+++ b/host/lib/transport/udp_zero_copy_asio.cpp
@@ -27,7 +27,8 @@ using namespace uhd::transport;
 /***********************************************************************
  * Constants
  **********************************************************************/
-static const size_t MIN_SOCK_BUFF_SIZE = size_t(100e3);
+//enough buffering for half a second of samples at full rate on usrp2
+static const size_t MIN_SOCK_BUFF_SIZE = size_t(sizeof(boost::uint32_t) * 25e6 * 0.5);
 static const size_t MAX_DGRAM_SIZE = 1500; //assume max size on send and recv
 static const double RECV_TIMEOUT = 0.1; //100 ms
 
@@ -159,6 +160,12 @@ template<typename Opt> static void resize_buff_helper(
     //otherwise, ensure that the buffer is at least the minimum size
     else if (udp_trans->get_buff_size<Opt>() < MIN_SOCK_BUFF_SIZE){
         resize_buff_helper<Opt>(udp_trans, MIN_SOCK_BUFF_SIZE, name);
+        if (udp_trans->get_buff_size<Opt>() < MIN_SOCK_BUFF_SIZE){
+            std::cerr << boost::format(
+                "Warning: the %s buffer size is smaller than the recommended size of %d bytes.\n"
+                "    See the USRP2 application notes on buffer resizing."
+            ) % name % MIN_SOCK_BUFF_SIZE << std::endl;
+        }
     }
 }