serial port problem - Kernel

This is a discussion on serial port problem - Kernel ; Hello! I have problems with connecting to any equipment since kernel 2.6.24 (Ubuntu 8.04)- if I connect cisco switch or router I can't do anything with it, but when I boot previos kernel (from Ubuntu 7.10 ) all is OK. ...

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Thread: serial port problem

  1. serial port problem

    Hello!

    I have problems with connecting to any equipment since kernel 2.6.24
    (Ubuntu 8.04)-
    if I connect cisco switch or router I can't do anything with it, but
    when I boot previos kernel (from Ubuntu 7.10 )
    all is OK.
    Today I did upgrade to Ubuntu 8.10 (kernel 2.6.27) and still have the
    same problem.
    So I downloaded and installed kernel 2.6.27.4 and still have the same
    problem.
    I connected zyxel modem to port and I see that it gets commsnds- it's
    data lamp blinks, but I get nothing.
    Situation is different on my colleague machine- since ubuntu 8.04 he can
    see in minicom or gtkterm how connected router boots,
    but then he can't send someting over several port to router.
    I created bug report in ubuntu's launchpad, but there is no solution.
    As I now see this problem exists with kernel from kernel.org could you
    tell me how can I find where problem is?

    Thank you!


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  2. Re: serial port problem

    > I connected zyxel modem to port and I see that it gets commsnds- it's
    > data lamp blinks, but I get nothing.
    > Situation is different on my colleague machine- since ubuntu 8.04 he can
    > see in minicom or gtkterm how connected router boots,
    > but then he can't send someting over several port to router.
    > I created bug report in ubuntu's launchpad, but there is no solution.
    > As I now see this problem exists with kernel from kernel.org could you
    > tell me how can I find where problem is?


    I had a similar problem trying to get a dial-up modem working a couple
    of months ago. I could use minicom to connect to the modem and type AT
    commands and read the responses, but whenever I dialled up I would see
    "CONNECT 48000" and that would be it. I couldn't send or receive data
    from the other end. After about a minute the ISP I was calling would
    time out and disconnect me.

    I have no idea what the problem was, I even went to the trouble of
    buying extra serial ports on a PCI card thinking the hardware was
    faulty, but nothing helped. In the end I downgraded to 2.6.17.8 (as
    this version was running on another PC that worked fine with the modem)
    and suddenly the whole thing worked perfectly.

    So it looks like some bug was introduced into the serial driver at some
    point, and if you're having problems it must still be in the current
    kernel version. I would suggest trying 2.6.17.8 instead (as that worked
    for me), and if it works for you too you might want to try upgrading
    until you find which version stops working - then we will know when the
    problem was first introduced.

    Cheers,
    Adam.

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