On Fri, Jul 05, 2024 at 06:45:50PM +0800, Yanteng Si wrote:

在 2024/7/5 18:16, Serge Semin 写道:

quoted

quoted

quoted

Seeing the discussion has started anyway, could you please find out
whether the multi-channel controller will still work if the MSI IRQs
allocation failed? Will the multi-channel-ness still work in that
case?

Based on my test results:

In this case, multi-channel controller don't work. If the MSI IRQs
allocation

failed, NIC will work in single channel.

What does "NIC will work in single channel" mean? Do the driver
(network traffic flow with a normal performance) still work even with
the plat->tx_queues_to_use and plat->rx_queues_to_use fields set to
eight? If it's then the multi-channel-ness still seems to be working
but the IRQs are delivered via the common MAC IRQ. If you get to
experience the data loss, or poor performance, or no traffic flowing
at all, then indeed the non-zero channels IRQs aren't delivered.

So the main question how did you find out that the controller work in
single channel?

sorry, I meant that if the MSI allocation failed, it will fallback to INTx,
in which case

only the single channel works.  if the MSI allocation failed, the
multi-channel-ness

don't work.

Could you please clarify what are the symptoms by which you figured
out that the "multi-channel-ness" didn't work?

Suppose you have an LS2K2000 SoC-based device, the
plat->tx_queues_to_use and plat->rx_queues_to_use to eight and the
loongson_dwmac_msi_config() function call is omitted. What is
happening with the activated network interface and with the traffic
flow then?

-Serge(y)