The net common is too slow in usrp2 firmware to figure out if its vrt data.

Added a custom function to tell if a packet is vrt data, seems to be feeding fast enough at this rate...
Fixed some buffer size calculation logic.

3 files changed, 13 insertions, 12 deletions

diff --git a/host/lib/usrp/usrp2/dsp_impl.cpp b/host/lib/usrp/usrp2/dsp_impl.cpp
index a57f5ff2d..8fdfd685f 100644
--- a/host/lib/usrp/usrp2/dsp_impl.cpp
+++ b/host/lib/usrp/usrp2/dsp_impl.cpp
@@ -82,12 +82,7 @@ void usrp2_impl::update_ddc_enabled(void){
     out_data.data.streaming.enabled = (_ddc_enabled)? 1 : 0;
     out_data.data.streaming.secs =  htonl(_ddc_stream_at.secs);
     out_data.data.streaming.ticks = htonl(_ddc_stream_at.ticks);
-    out_data.data.streaming.samples = htonl(
-        _mtu/sizeof(uint32_t) -
-        USRP2_HOST_RX_VRT_HEADER_WORDS32 -
-        USRP2_HOST_RX_VRT_TRAILER_WORDS32 -
-        ((2 + 14 + 20 + 8)/sizeof(uint32_t)) //size of headers (pad, eth, ip, udp)
-    );
+    out_data.data.streaming.samples = htonl(_max_samples_per_packet);
 
     //send and recv
     usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index 8b45a708a..0ca2409c3 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -127,12 +127,11 @@ size_t usrp2_impl::send_raw(
     }
     vrt_hdr_flags |= (metadata.start_of_burst)? (0x1 << 25) : 0;
     vrt_hdr_flags |= (metadata.end_of_burst)?   (0x1 << 24) : 0;
-    num_vrt_hdr_words += asio::buffer_size(buff)/sizeof(uint32_t);
 
     //fill in complete header word
     vrt_hdr[0] = htonl(vrt_hdr_flags |
         ((_tx_stream_id_to_packet_seq[metadata.stream_id]++ & 0xf) << 16) |
-        (num_vrt_hdr_words & 0xffff)
+        ((num_vrt_hdr_words + asio::buffer_size(buff)/sizeof(uint32_t)) & 0xffff)
     );
 
     //load the buffer vector
@@ -151,6 +150,8 @@ size_t usrp2_impl::recv_raw(
     const boost::asio::mutable_buffer &buff,
     uhd::metadata_t &metadata
 ){
+    metadata = metadata_t(); //clear metadata
+
     //handle the case where there is spillover
     if (asio::buffer_size(_splillover_buff) != 0){
         size_t bytes_to_copy = std::min(
@@ -198,9 +199,9 @@ size_t usrp2_impl::recv_raw(
     _rx_stream_id_to_packet_seq[metadata.stream_id] = my_seq;
 
     //extract the number of bytes received
-    size_t num_words = (vrt_header & 0xffff);
-    num_words -= USRP2_HOST_RX_VRT_HEADER_WORDS32;
-    num_words -= USRP2_HOST_RX_VRT_TRAILER_WORDS32;
+    size_t num_words = (vrt_header & 0xffff) -
+        USRP2_HOST_RX_VRT_HEADER_WORDS32 -
+        USRP2_HOST_RX_VRT_TRAILER_WORDS32;
     size_t num_bytes = num_words*sizeof(uint32_t);
 
     //handle the case where spillover memory was used
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index 43f32c6e6..037aed477 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -108,7 +108,12 @@ private:
     uhd::dict<uint32_t, size_t> _tx_stream_id_to_packet_seq;
     uhd::dict<uint32_t, size_t> _rx_stream_id_to_packet_seq;
     static const size_t _mtu = 1500; //FIXME we have no idea
-    static const size_t _max_samples_per_packet = _mtu/sizeof(uint32_t);
+    static const size_t _max_samples_per_packet =
+        _mtu/sizeof(uint32_t) -
+        USRP2_HOST_RX_VRT_HEADER_WORDS32 -
+        USRP2_HOST_RX_VRT_TRAILER_WORDS32 -
+        ((2 + 14 + 20 + 8)/sizeof(uint32_t)) //size of headers (pad, eth, ip, udp)
+    ;
     uint32_t _tmp_send_mem[_mtu/sizeof(uint32_t)];
     uint32_t _tmp_recv_mem[_mtu/sizeof(uint32_t)];
     uint32_t _spillover_mem[_mtu/sizeof(uint32_t)];