I have a flowgraph with a custom RFNoC block in the middle. That block has 2 inputs and 2 outputs. Just to get started and work out the MIMO functionality, all I do is cross the the inputs to the outputs (so input 0 comes out output 1). What I am seeing is that if I run the flowgraph after loading a fresh bitfile, I don't get anything out of my output who should be passing the data from an RFNoC radio->DDC and I see "timeout on chan 0" scrolling past on the screen. But, if I run the same flowgraph a second time, it suddenly works fine (as well as subsequent runs afterwards until I reload the bitfile). It doesn't matter if I swap the inputs to the special block, it always reads "timeout on chan 0" and the output stream on my block that should be displaying that data is dead the first run after a reload. I am guessing that "timeout on chan 0" is releated to either the Radio or DDC block as it is consistently 0 even when I move it around on my 2 inputs (if I pull out the DDC, I see the same issues, so it seems to be something between the radio and my block). That said, I don't see this issue if I run the rfnoc_ddc.grc example from Ettus which also uses a Radio and DDC. I could believe that it has something to do with a reset in my block (like the fact that there are two clear_tx_seqnum flags), I am just confused why the issue moves around depending on where the rfnoc/ddc is connected (yet the timeout does not). If I remove the radio/ddc and use an rfnoc split stream to take my GR signal source, I don't see these issues. So I cannot figure out what is not playing nicely between my block and the RFNoC radio. BUT... If I go from the radio into a split stream to my two inputs, it works right the first time, and then doesn't work again after that (so almost the reverse issue as I've started with, but I REALLY feel like something with my block dealing with 2 inputs and 2 outputs is causing this issue.
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