I've been using the latest git version of gnuradio and trying to get Doug's start_rx_streaming_at patch (now merged with the git version) to work. I don't think there's any support via gr-usrp2 so I've modified usrp2_source_base (temporarily) to call start_rx_streaming_at(0,0,0) (i've tried using 1 as well as I'm not sure if the fpga starts at 0 or 1) instead of start_rx_streaming(0).
When I do this everything compiles and I can start a flowgraph, unfortunately no samples ever seem to be outputted from the block.
I've been testing with the following flowgraph (and with usrp2_fft.py etc which shows the FFT window but no data)
The produced file is empty. (I've left running for a while in case the timestamp was missed and also added sync_to/every_pps but the result is the same)
The USRP2 is using firmware compiled from the git sourcecode -- looking through the code I think using the incorrect firmware would just cause the start_rx_streaming_at command to act like the normal start_rx_streaming command.
Has anyone got any ideas on what I might have missed?