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Dead eth0 PHY after ifconfig eth0 up with no ethernet cable

robert chen97444
Prodigy 130 points
Other Parts Discussed in Thread: AM1808

Board: am1808 EVM

Kernel: prebuilt uImage-am180x-evm.bin (SDK: ti-sdk-am180x-evm-05.03.02.00-Linux-x86-Install)

Rootfs: extracted base-rootfs-am180x-evm.tar.gz (Seems not relevant. It's from the SDK, too.)

I use AM1808 EVM and encounter a problem that the ethernet PHY is easily dead (about 50%) if I "ifconfig eth0 up" without plugging in ethernet cable.

Reproduce procedure:

1. Power on WITHOUT plugging ethernet cable (MUST)

2. Boot into linux shell

> ifconfig eth0 up
davinci_mdio davinci_mdio.0: resetting idled controller
net eth0: attached PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=0:00, id=7c0f1)

(I traced and found the behavior is: "up" -> reset emac -> reset mdio)

3. Plug in ethernet cable after 5 sec
--> Problem: Ethernet port LED isn't blinking anymore! Of course, PHY can't link up. Looks like the PHY is dead! Replugging or "ifconfig down and up" can't help PHY recover.

What I can do is reboot the system and let PHY recover.

Q1: Is the PHY module inside am1808? Or it resides on the board? Should it be reset after MDIO reset?

Q2: Is the PHY dead?

I suppose this usage is very common. Please help us clarify and solve the problem.

  • 0
    Intellectual 710 points

    Hi!

    I had some other strange problems with the davinci emac in the past, so I would like to reproduce your problem here. Could you please post the output of ifconfig after the PHY is dead? Please also post the kernel version of the SDK (output of uname -a)

    Regards, Christian

  • 0 in reply to Christian Riesch
    Prodigy 130 points

    At that point, no message is output.

    1. Boot into linux shell without plugging ethernet cable

    ~ # ifconfig eth0 up
    [ 66.364031] davinci_mdio davinci_mdio.0: resetting idled controller
    [ 66.371239] net eth0: attached PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=0:00, id=7c0f1)


    2. Plug in ethernet cable...No blinking PHY LED...

    / # ifconfig eth0 up
    / # ifconfig eth0 up
    / # ifconfig eth0 down
    / # ifconfig eth0 up
    davinci_mdio davinci_mdio.0: resetting idled controller
    net eth0: attached PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=0:00, id=7c0f1)
    / # ifconfig eth0 up

    3. Still no blinking PHY LED...

    / # uname -a
    Linux (none) 2.6.37 #2 PREEMPT Thu Dec 15 12:43:56 CST 2011 armv5tejl GNU/Linux
    / #

  • 0 in reply to robert chen97444
    Guru 20755 points
    Hi Robert,

    Did you find a result ?
    I have the same issue...

    Best Regards,
    Ran