Hi Niall, Thanks for the lead.
I checked my driver setup and found that the transmit threshold was left at the default of 64. But then I also read in the processor reference that the threshold is not used in store-and-forward mode, which is what I use for checksum offloading. In store-and-forward mode, transmission starts as soon as a full frame resides in the Transmit FIFO (MCU dedicated 2kB). It gets there through a DMA transfer. The MAC expects full frames, and that is what the ethernet driver sets up, and that is what the netif_low_level_output() passes to the ethernet driver... So that all looks fine to me. Going to add some code to try to trace lwip ACK generation through to the MAC... -- View this message in context: http://lwip.100.n7.nabble.com/TCP-retransmissions-and-duplicate-ACKs-tp21835p21838.html Sent from the lwip-users mailing list archive at Nabble.com. _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
