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AM3352: Login over serial port

FFatima
Intellectual 440 points

Part Number: AM3352

Hi,

I am using TI SDK (Aragao Krogoth Configuration). i have enabled access over serial port by setting bootargs in bootloader: 

setenv bootargs console=ttyO0,115200n8 console=tty0 ${optargs} root=/dev/mmcblk1p2 rootfstype=${mmcrootfstype} ${cmdline} panic=1

Most of the times, access over serial port works fine and the login prompt appears. I am able to login too. However at times, i am unable to enter anything like username/password over serial port. It appears as though the serial access or the login program freezes - not allowing me to enter anything. When this happens, I need to reboot the system to be able to login over serial port again. How do I fix this?

Regards,

Fariya

  • 0
    TI__Guru 74450 points

    Hi Fariya,
    If you remove "panic=1" or modify it to "panic=longer...", any kernel panic message observed?
    Best,
    -Hong

  • 0 in reply to Hong Guan64
    Intellectual 440 points

    Hi,

    The whole system doesn't hang just the serial port access program freezes. So this doesn't help.

  • 0 in reply to FFatima
    TI__Guru 74450 points

    Hi Fariya,
    I'm passing it to my colleague for any pointers to debug kernel serial terminal login lockup.
    Best,
    -Hong

  • 0 in reply to FFatima
    TI__Guru**** 175821 points

    Hi Fariya,

    Which version of the SDK do you use?

    Do you use Windows or Linux PC to connect to AM3352 console? Which program do you use?

    When the console freeze issue happens, does the login prompt show up on the AM3352 console?  if you just press the "Enter' key, does the console responds to the "Enter" key and scroll up?

  • 0
    Intellectual 440 points

    Hi Bin,

    Below are the replies:

    Which version of the SDK do you use?

    Answer> We use Arago Krogoth build

    Do you use Windows or Linux PC to connect to AM3352 console? Which program do you use?

    Answer> We use putty over Windows 10. Have tried over Linux using minicom as well - no difference in behavior, the serial console freezes at times.

    When the console freeze issue happens, does the login prompt show up on the AM3352 console?  if you just press the "Enter' key, does the console responds to the "Enter" key and scroll up?

    Answer> The console when it has freezed up, it doesn't respond to any key at all. 

  • 0 in reply to FFatima
    TI__Guru**** 175821 points

    Hi Fariya,

    Please ensure HW flow-control is disabled in Putty or minicom.

    How often do you see the issue? Does it happen on all boards?

    Can you please use a scope to measure the baud rate? is it exactly 115200?

    Can you reproduce the issue on U-Boot prompt?

  • 0 in reply to Bin Liu
    Intellectual 440 points

    Hi Bin,

    Hw flow control is already disabled in putty and minicom. This issue is seen 1 in 3-4 attempts (of attempting to access serial console after kernel loads) and on all boards, so its quite often. This issue is not replicable on u-boot prompt. 

    Regards,

    Fariya

  • 0 in reply to FFatima
    TI__Guru**** 175821 points

    Hi Fariya,

    This sounds like a software issue in Linux.

    I am not familiar with Arago, but is Arago Krogoth released on 2016? What is the kernel version do you use? 'uname -a' command will tell that.

    Which UART driver do you use, 8250_omap.c or omap_serial.c?

    Please use a scope to check the UART baud rate.