Re: [lwip-users] Randomly delayed frame (STM32070 package including LwIP v1.4.1)

[address@hidden]

Am 04.01.2019 um 21:15 schrieb stevestrong:
> Jason, thanks for your comment.
>
> I saw that no Rx packets were ever lost, no Rx/TX buffer over- or under-flow
> ever occurred.
> That finally made me think on DMA and PHY.
> I realized that currently my PHY works in 100Mbp half-duplex mode, and that
> could eventually be a problem, when many packets arrive and the PHY tries to
> send some data in the same time (although the PHY should probably manage
> this).

Actually, it is the MAC that has to handle half-duplex retransmission, 
not the PHY. The PHY can report "half duplex" via MDIO as a result of 
autonegotiation, but if the MAC is not set to half duplex, too, you'll 
get lost TX packets.

Regards,
Simon

> Then I found on Internet a site which offers a solution for DP83848, a patch
> for MBED ETH lib, to work in full-duplex mode.
>
> I implemented it, and ... voila: no more lost packets in 100 tries!
> No more delayed packets. Success!
>
> So I can conclude that the issue was most probably due to the heavy traffic
> when PHY is working in half-duplex mode.
> Does this make sense?
>
> Anyway, thank you all for the invested time and effort, I really appreciate
> it.
>
> Steve
>
>
>
> --
> Sent from: http://lwip.100.n7.nabble.com/lwip-users-f3.html
>
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