On Tue, 2009-02-10 at 07:50 +0800, Sam Ruby wrote:
> 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
Do you have an opportunity to try the boot option of "acpi=off" as
suggested by Lenb?
From the log it seems that there exists the following warning
message:
>MP-BIOS bug: 8254 timer not connected to IO-APIC
Can you try the following boot options?
a. acpi_use_timer_override
b. acpi_skip_timer_override
c. noapic
Thanks.
> >
> > 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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