Unstable network connection in Android Nougat because of TCP offload enabled

systemservice

Hello,

I think I'm experiencing similar networking problems as described here and other forums.

https://github.com/Fourdee/DietPi/issues/2028

It looks like different RK3399 devices are affected, for example: NanoPi M4, RockPro64, OrangePI and maybe others.

But what about Firefly-RK3399, is TCP offload enabled there, and if yes, how to disable it?
I think there is no ethtool available in Android Nougat, but maybe there is another way to disable it?

Thank you.
Arthur

penguin

Does this affect you in Android? Could you please tell us how to reproduce
the problem in Android?

systemservice

Yes, this happens in Android 7.1.2. I'm using more than 15 pieces of RK3399 devices for different projects.
If I google for "RK3399 network error" or something like that, then I see that NanoPi M4, RockPro64 and OrangePI seem to have an issue which was solved by "ethtool -K eth0 rx off tx off".
I have already build "ethtool" for Android and used it to disable TCP offloading as described in the forums, but it didn't solve the issue.

If I knew, that Firefly-RK3399 with Android7/8 is NOT affected, then I would probably switch to Firefly-RK3399.

Description:

All devices (more than 15) are used 24/7. They are downloading small HTTP content every minute, usually below 100KB, but sometimes about 10 MB.

Usually several times a week one of the devices gets OFFLINE suddenly, sometimes for 5 min., sometimes for 30 min, somtimes for longer than 1h. If you sum all devices this happens nearly every day and sometimes several times a day.

In dmesg-Log I see, that the device switches from 100Mbit link speed to 10Mbit, and than back to 100Mbit. It is offline during this time.
Log:

1. [1487388.081884] rk_gmac-dwmac fe300000.ethernet eth0: Link is Up - 10Mbps/Half - flow control off
   
2. # So, 17. Feb 2019 08:28:51
   
3. [1488648.768330] rk_gmac-dwmac fe300000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off
   
4. # So, 17. Feb 2019 23:14:46
   
5. [1541803.160657] rk_gmac-dwmac fe300000.ethernet eth0: Link is Up - 10Mbps/Full - flow control off
   
6. # So, 17. Feb 2019 23:24:46
   
7. [1542403.393871] rk_gmac-dwmac fe300000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off
   

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At all switch ports these devices are connected to, I/O errors are logged in the port statistics. The error counter increases, when the device is offline. Other clients connected to the same CISCO 100Mbit switch are not affected.

May Firefly-RK3399 have the same issue?

penguin

Can you use iperf for android to reproduce this error?