Re: Disk ordering on a PowerMac MDD G4
Sorry, it was my fault -- I was using the wrong initrd. Everything is
now working as expected.
On 10/13/23 9:49 AM, Stan Johnson wrote:
> Hello,
>
> Recent kernels (starting around 6.4) have made it progressively more
> difficult to predict disk ordering on the PowerMac MDD G4. My system has
> four disks, two on the 100 MHz bus and two on the 66 MHz bus:
>
> 100 MHz bus:
> master - should be sda
> slave - should be sdb, often is seen as sda
>
> 66 MHz bus:
> master - should be sdc, often is seen as sda
> slave - should be sdd
>
> While I use "LABEL=Debian_xxx" in /etc/fstab, in Yaboot I need to
> specify something like "root=/dev/sda15" since "root=LABEL=xyz" and
> "root=UUID=abc" not only don't work but are seen as syntax errors
> requiring rescue from CD.
>
> It looks like I have three choices (I prefer option 1):
>
> 1) Convert from Yaboot to GRUB. I would prefer that the distributed
> (official) version of GRUB allow booting of Mac OS X and Mac OS 9 from
> the GRUB menu without needing custom changes (I'm aware of the previous
> thread discussing how to modify GRUB to allow it to boot Mac OS X and
> Mac OS 9 volumes, but I don't know whether those changes went upstream
> to the GRUB maintainers). I would also need to install and configure
> GRUB and then remove it or disable GRUB updates, since the AppleBoot
> partition remains mounted by default (and that's a security issue).
>
> 2) See if there are kernel options to cause the master disk on the 100
> MHz bus to be seen as sda. The kernel (or udev) should never pick a disk
> on the 66 MHz bus as sda if there is a master disk on the 100 MHz bus.
> I've tried "Assign PCI bus numbers from zero individually for each PCI
> domain" and "Use pci_to_OF_bus_map (deprecated)", but the selection of
> sda appears to be random. Since Yaboot runs the initrd correctly from
> what should be sda (master disk on the 100 MHz bus), the problem appears
> to be happening in the initrd or the initrd's udev (the kernel hangs
> when it can't find the root fs, which it usually thinks is on sdb or sdc).
>
> 3) Only use a single disk on this system, which should cause sda to be
> identified correctly.
>
> thanks for any constructive suggestions
>
> -Stan
>
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