Re: [PATCH] Revert "net: stmmac: Do not keep rearming the coalesce timer in stmmac_xmit"

Hi Jerome,

On 24-08-2018 10:04, Jerome Brunet wrote:

This reverts commit 4ae0169fd1b3c792b66be58995b7e6b629919ecf.

This change in the handling of the coalesce timer is causing regression on
(at least) amlogic platforms.

Network will break down very quickly (a few seconds) after starting
a download. This can easily be reproduced using iperf3 for example.

The problem has been reported on the S805, S905, S912 and A113 SoCs
(Realtek and Micrel PHYs) and it is likely impacting all Amlogics
platforms using Gbit ethernet

No problem was seen with the platform using 10/100 only PHYs (GXL internal)

Reverting change brings things back to normal and allows to use network
again until we better understand the problem with the coalesce timer.

Apologies for the delayed answer but I was in FTO.

I'm not sure what can be causing this but I have some questions
for you:
    - What do you mean by "network will break down"? Do you see
queue timeout?
    - What do you see in ethtool/ifconfig stats? Can you send me
the stats before and after network break?
    - Is your setup multi-queue/channel?
    - Can you point me to the DT bindings of your setup?

Thanks and Best Regards,
Jose Miguel Abreu