Messages in this thread | | | Date | Mon, 09 Feb 2009 18:50:35 -0500 | From | Sam Ruby <> | Subject | Re: [APIC] Kernel panic, rsync corruption, intel q8200, 2.6.28-rc8 |
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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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