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eth1 different MAC address on reset on Vayu J6 Platform

Kaushal
Intellectual 690 points

Hi,

I've a TI J6 Vayu EVK Infotainment kit running Android 6AK1.1. I'm very new to this development environment and Android internals in general. So, please bear with me.

Since this platform doesn't have wifi module, on my board eth1 is plugged into an Apple Airport Express (AE) (which acts as a wifi to ethernet converter).

Everything works ok (i.e. TI board gets internet) if AE connects to a regular wifi n/w such as home or office. However, if I connect AE to a cellular wifi hotspot the TI board doesn't like it and doesn't get IP address. I 100% made sure that other devices can connect to cellular hotspot and it's all good. I also tried T-Mobile and Verizon hotspots and it's the same problem.

So, can anyone shed some light on this, why the TI board doesn't like cell hotspots to ethernet connection. I read in several forums here, that eth0/eth1 MAC addresses are randomly assigned at power up and I did notice it on my setup. Could my issue be related to that?

Just to summarize, I need to get internet on the TI Vayu kit via cellular wifi hotspot to ethernet connection in eth1.

Thanks,

Kaushal

  • 0
    TI__Guru**** 161600 points

    Hi Kaushal, 


    Have you tried to connect your AE device to your host PC, establish connection to cellular hotspot & see if your pc has internet connection?

    If you have internet connection on your pc with the above setup, then, I think, that having different MAC addresses every time you power up the board, is very likely to be the problem. 

    I checked on my vayu evm, and indeed Android driver assigns different MAC, every time the board is reset, which may be a problem if your network is not configured accordingly. 

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 690 points

    Hi Yordan,

    Thanks for your response. Yes, my host PC does get a connection even if its ethernet cable comes from AE. i.e. I plugged the same ethernet cable that I use for my Vayu board to my PC and the PC gets the connection.

    It's so strange that the Vayu board gets connection as long as AE is connected to a regular wifi network and not cell hotspot.

    So, is there any solution to this? I have the ability to build AFS but not the kernel. Can I reprogram the board to have a permanent MAC address? 

    Thanks,

    Kaushal

  • 0 in reply to Kaushal
    TI__Guru**** 161600 points

    Hi Kaushal,

    It is possible, you can refer to GLSDK kernel driver for the ethernet & can try to implement the solution in Android (in GLSDK release MAC address is always the same), but that would require rebuilding the kernel. 

    Does your AE copies the MAC address of the vayu evm? Can it be configured (assign it a constant MAC)?

    What is the output of netcfg, when you try to connect to the cellular hotspot?

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 690 points

    Hi Yordan,

    Does your AE copies the MAC address of the vayu evm? Can it be configured (assign it a constant MAC)?

    I am not sure how the AE works internally. But the AE config utility doesn't seem to have any settings to assign a constant MAC to it's ethernet connected device. Also tried the AE with static IP address, no change. PC can work off of hotspot but the Vayu can't.

    I do see the Vayu device on my hot spot generating phone except that Vayu doesn't have IP address. I also made the hotspot both secure & insecure, but no difference there either.

    What is the output of netcfg, when you try to connect to the cellular hotspot?

    With cell hotspot wifi:

    lo       UP                                   127.0.0.1/8   0x00000049 00:00:00:00:00:00

    sit0     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    eth1     UP                                     0.0.0.0/0   0x00001043 82:dc:a3:5a:53:34

    eth0     DOWN                                   0.0.0.0/0   0x00001002 de:de:07:c5:6c:f3

    can1     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    can0     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    With regular Wifi

    lo       UP                                   127.0.0.1/8   0x00000049 00:00:00:00:00:00

    sit0     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    eth1     UP                              192.168.106.39/24  0x00001043 62:9f:44:e1:97:23

    eth0     DOWN                                   0.0.0.0/0   0x00001002 62:d3:6c:b2:72:fe

    can1     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    can0     DOWN                                   0.0.0.0/0   0x00000080 00:00:00:00:00:00

    Btw, I had tried compiling kernel a month ago, but the build failed so didn't pursue further since I really didn't need it.

     

    Thanks,

    Kausahal