Hi,

I have an issue with rte_eth_rx_burst() for IGC poll mode driver never returning any packets and need some advice.

I have this network port:
09:00.0 Ethernet controller: Intel Corporation Ethernet Controller I225-V (rev 03)

Bound to igb_uio:
Network devices using DPDK-compatible driver
============================================
0000:09:00.0 'Ethernet Controller I225-V 15f3' drv=igb_uio unused=igc

I'm testing this both with testpmd and my own app, which works fine with other drivers such as net/ena and net/i40e. I'm using single RX/TX queue pair with default configs with rte_eth_promiscuous_enable() and rte_eth_allmulticast_enable().

The device seems to rte_eth_dev_start() fine, and rte_eth_stats_get() seem to be detecting inbound packets. Below is the output from testpmd:

> Press enter to exit
> eth_igc_interrupt_action(): Port 0: Link Up - speed 1000 Mbps - full-duplex
>
> Port 0: link state change event
> ^CTelling cores to stop...
> Waiting for lcores to finish...
>
> ---------------------- Forward statistics for port 0 ----------------------
> RX-packets: 129 RX-dropped: 800 RX-total: 929
> TX-packets: 0 TX-dropped: 0 TX-total: 0
> ----------------------------------------------------------------------------
>
> +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++
> RX-packets: 129 RX-dropped: 800 RX-total: 929
> TX-packets: 0 TX-dropped: 0 TX-total: 0
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> Done.

However, rte_eth_rx_burst() never returns anything, neither in testpmd nor in my own app.

In my own app, I log both rte_eth_stats_get() and non-zero xstats from rte_eth_xstats_get_by_id():

> 07:02:13.406873186 INF stats.rx : 0
> 07:02:13.406892616 INF dev_stats.ipackets : 78
> 07:02:13.406903636 INF dev_stats.opackets : 0
> 07:02:13.406914166 INF dev_stats.imissed : 0
> 07:02:13.406924536 INF dev_stats.ierrors : 0
> 07:02:13.406934116 INF dev_stats.oerrors : 0
> 07:02:13.406943956 INF dev_stats.rx_nombuf : 0
> 07:02:13.407247777 INF xstats rx_good_packets : 78
> 07:02:13.407257147 INF xstats rx_good_bytes : 17205
> 07:02:13.407265267 INF xstats rx_size_64_packets : 6
> 07:02:13.407274627 INF xstats rx_size_65_to_127_packets : 31
> 07:02:13.407285757 INF xstats rx_size_128_to_255_packets : 22
> 07:02:13.407297537 INF xstats rx_size_256_to_511_packets : 16
> 07:02:13.407309127 INF xstats rx_size_512_to_1023_packets : 3
> 07:02:13.407321327 INF xstats rx_broadcast_packets : 8
> 07:02:13.407331597 INF xstats rx_multicast_packets : 64
> 07:02:13.407346357 INF xstats rx_total_packets : 78
> 07:02:13.407355547 INF xstats rx_total_bytes : 17205
> 07:02:13.407364127 INF xstats rx_sent_to_host_packets : 7807:02:13.407375347 INF xstats interrupt_assert_count : 1

Still, rte_eth_rx_burst() never returns anything.

It's worthwhile to note that rte_eth_rx_burst() works fine when I, instead of net/igc, use net/ena (with ENA card) or net/i40e (Intel x710 card).

The debug log from EAL and net/igc is attached, in case that helps.
There's a warning "igc_rx_init(): forcing scatter mode", but I've already tried changing my mbuf sizes so that the warning goes away but that also didn't help.

Any advice?

Thanks,
Fabio