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DP83822I: DP83822 randomly link failure issue

Yang Wu
Expert 3330 points
Part Number: DP83822I

Hi Team,

My customer met DP83822 randomly link failure issue and suspects software issue. I set this thread for discussion. 

thanks.

Best regards,

Yang

  • 0
    Prodigy 30 points

    Background and phenomenon： During the whole machine test, log on to the interface of a web page management machine through this network port, and then restore the factory settings and the default values. After that, there will be an automatic restart process of the minimum Linux system, after the restart, the network port cannot be connected and the Ping fails.In Linux, the operation command ethtool eth1. the Link status is NO, and the actual network cable is plugged

    Depaint：The fault phenomenon can be reproduced；

    The method on Link can be used for software operation: under the condition of continuous power supply, ifconfig eth1 down on the network port, and then ifconfig eth1 up, you can run the ethtool eth1 in Linux to detect the Link status. Yes

  • 0 in reply to zhuangzhaung yue
    TI__Mastermind 39855 points

    Hello,

    During the error condition, can you access the PHY's registers? Does it show there or on board that link is still up on LED_0?

    Sincerely,

    Gerome

  • 0 in reply to Gerome Cacho
    Prodigy 30 points

    When a fault occurs, connect the serial port and check the faulty network port. The status register can be read, and the corresponding No link is displayed, but in fact, the Link light of my network cable is always on normally.

  • 0 in reply to Gerome Cacho
    Prodigy 30 points

    Supplementary Test waveform diagram: When reset occurs, the MDIO bus has the reading operation process. Channel 1 is MDIO data, Channel 2 is MDC clock, and channel 3 is reset

  • 0 in reply to zhuangzhaung yue
    TI__Mastermind 39855 points

    Hello,

    I wanted to confirm this; you are saying that link light is on which is meaning there is link. However, register is saying no link? What value are you reading for the register? Have you read this multiple times over, as this bit can be latched low?

    Sincerely,

    Gerome

  • 0 in reply to Gerome Cacho
    Prodigy 30 points

    Software engineers can only read the Link status Value of this register, and the values read many times are No link. How to read other values of this register in linux, previously, we provided a tool M4. the read value changes every time, so it is impossible to determine its accuracy, or whether there are any special requirements for using that tool to ensure the accuracy of reading.

  • 0 in reply to Gerome Cacho
    Intellectual 320 points

    Hi Gerome,

    we exec "ethtool eth1" in command line, and find the link status is no, not yes.

  • 0 in reply to zhicheng zhang
    TI__Mastermind 39855 points

    Hi,

    So it appears that link is intermittent. Can you please share the values you read?

    In addition, what is the cable type and length, as well as the link partner?

    You stated in your background that if you restore factory settings, you are able to trip this behavior case. In that case, was there ever any instance of stable linkup ever?

    Sincerely,

    Gerome