Re: Booting 64-bit Linux on a Macbook5,2

[Patrick Doyle]

Thank you again for taking the time to reply and to help me work through this...

On Thu, Sep 23, 2010 at 10:01 AM, Colin Watson <address@hidden> wrote:
> On Thu, Sep 23, 2010 at 09:47:44AM -0400, Patrick Doyle wrote:
>> reading around, it seems that some folks have been able to boot with
>> full capabilities (i.e. ACPI and both cores) when booting via EFI.
>
> I'm afraid I don't know how you might do that.  The best way to find out
> why your system is hanging at boot is to attach a serial console to it,
> if you can, and boot it with console=ttyS0 so that you can see the early
> console messages.
Alas, my MacBook doesn't have a built in serial port.  I suspect that
trying to get early console messages out through a USB serial port
dongle (especially the cheap Radio Shack one that I have) is doomed to
frustration.

OTOH, I have seen references to certain kernel command line parameters
that make me think that a) EFI provides some sort of console API, and
b) that Linux might have some sort of support for output to that
console.  I'll add that to the list of things to look into.

> To me it sounds as if your machine has 64-bit EFI but that for some
> reason the 64-bit kernel oopses at boot, before the console comes up.
> I've seen this before and a serial console is about the only practical
> way to debug it.

So, if my 64-bit EFI can boot a 64-bit grub (which seems to be the
case), can I reasonably expect to boot either a 32 or a 64 bit kernel
from grub?  Or should I only be able to boot a 64 bit kernel?

>
>> This might not be the correct forum to ask this, but does anybody know
>> what installing the "grub-efi-amd64" package really does for Ubuntu?
>> Does it replace the grub-pc package that was presumably installed off
>> the CD?
>
> On Ubuntu 10.04 LTS, grub-efi-amd64 installs the files but you have to
> install the actual boot loader yourself.  On Ubuntu 10.10, it should
> install the boot loader as well.  In both cases, it conflicts with
> grub-pc - you can only have one or the other installed at once.

Just to make sure I'm understanding this correctly, should I do
something vaguely similar to:

$ apt-get remove grub-pc
$ apt-get install grub-efi-amd64
$ grub-install /dev/sda3

... if I want an EFI aware, 64-bit grub installed as my bootloader?

If I do that, what should I expect to be differerent than the grub-pc
bootloader that was (presumably) installed when I installed Ubuntu?

The bootloader that was installed (in /dev/sda3) currently boots my
kernel, as long has I have acpi=off or maxcpus=1 flags set.

>
>> Should I be using that instead of compiling my own version of
>> grub-1.98 (in a VMware box on my Mac) and placing my own version in
>> /efi/grub?
>
> Well, it would probably at least save you compiling it.

Right now, when I compile it, I do so in order to produce a set of
files that I can place in /efi/grub on my MacOS file system.  If I
install grub-efi-amd64, it will be installed in the partition and in
files on my Linux file system,

Thanks again for helping me to work through this.

--wpd