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    SubjectRe: [APIC] Kernel panic, rsync corruption, intel q8200, 2.6.28-rc8
    Len Brown wrote:
    >>> Do you have a second computer around with a serial port ? If yes, then
    >>> please add the following to the kernel command line:
    >>>
    >>> earlyprintk=serial,ttyS0,115200 apic=debug
    >>>
    >>> and connect the serial ports with a null modem cable. Fire up a
    >>> terminal program on the second machine and capture the output.
    >> I do have a second computer, and went out and bought a null modem adapter for
    >> my serial cable and connected the two machines. I've tried installing minicom
    >> and also connecting it to ttyS0 at 115200 baud on the second machine, but when
    >> I boot the first machine I don't see any output on the terminal.
    >
    > /boot/grub/menu.lst:
    >
    > serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
    > terminal --timeout=300 serial console
    >
    > is what I use.
    >
    > this will give you a prompt from grub even before the kernel boots
    > so you can select (and edit) your kernel via menu over the serial line
    > if you wish.

    I've got that working now. I used minicom on the remote machine,
    capturing the output. You can see me fumbling around, editing the
    kernel command and booting here:

    http://intertwingly.net/stories/2009/02/09/minicom.out

    While it is difficult to make out what I did given line wrapping, etc,
    what I started with was:

    /boot/vmlinuz-2.6.27-11-generic
    root=UUID=4fce230e-fe72-4685-aab0-294ef1c20efa ro noapic quiet splash

    After editing, what I had was

    /boot/vmlinuz-2.6.27-11-generic
    root=UUID=4fce230e-fe72-4685-aab0-294ef1c20efa ro quiet splash
    earlyprintk=serial,ttyS0,115200 apic=debug

    As you can see, the last line I saw was "Starting up ...", after which
    point the "MP-BIOS bug: 8254 timer not connected to IO-APIC" etc output
    appeared on the monitor that is directly connected to the machine being
    booted (i.e., this text did not appear on the minicom session).

    > If this doesn't work, then the kernel earlyprintk is unlikely to work
    > also.

    At the moment, it looks like it works, but earlyprintk does not work for
    me, at least not on Ubuntu 8.10, kernel 2.6.27-11-generic.

    > Note that there may be some BIOS SETUP options related to the serial port
    > -- worth checking.
    >
    > Also, in minicom, be sure to turn off HW flow control
    >
    > there is a fancy serial console document someplace on this,
    > probably at http://tldp.org/

    As I have managed to get grub to talk to the serial console, I did not
    explore these options further. Please let me know if there is something
    in particular I should explore.

    > good luck,
    > -Len

    - Sam Ruby


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