PPC kernels: More Pegasos II-friendly kernel config

[Richard Chan]

Hi David,

Here's a bit of my experience with FC4:

0. I have totally rebuilt the FC4 kernel  2.6.12-1.1390_FC4 to get the
zImage.initrd.chrp. It is working well (though it was built using gcc
3.4 because that was all I had on my build machine - PPC64 RHEL AS 4 -
the gcc4 on RHEL AS 4 is too old to build the kernel because it ICEs
on the qlogic driver). In the next few days I'll try with gcc 4.0.1
with 2.6.12-1.1398_FC4.

1. Didn't have an installer so used one of the pre-installed Linuxen
to rsync an image over (from a PowerMac G4). With my new kernel the
whole thing works amazingly well. The chrp image can be booted by yaboot
and directly by OF.

vmlinux definitely isn't working (Sven Luther, responsible
for the Amiga partitioning patches to yaboot, attributes it both to
OF and yaboot. )

Quoth Sven Luther
>> Can someone explain the technical reason why yaboot doesn't boot
>>vmlinux
>> on Pegasos II?

>needs a new firmware upload, which is not quit ready yet.

>also yaboot is kinda brokenand uglmy, but this will be worked around,
>patience.

Also
>> What's with Pegasos II and vmlinux - any ideas?

>it's a size problem, and lack of free memory, and the fact that yaboot
>expect
>a not really standard conformant return from the claim call to allocate
>memory.

>btw, try mkvmlinuz :)

mkvmlinuz is a debianism - a kind of script to create vmlinuz but
requires object files from the kernel build (especially the stuff in
$BUILDTREE/arch/ppc/*) and the linker script
($SRCTREE/arch/ppc/boot/ld.script) to be kept around. I haven't got it
to work yet.


2. Userspace may need some help (or pointers) to get DRI to work because
of the unsupported (undetected?) AGP - I got DRI to work by forcing
BusType to "PCI" in  /etc/X11/xorg.conf; I noticed that YellowDog uses
Option "UseFBDev" - I wonder which is the "correct" way to do it?


But after all that, I'm delighted at how well the PPC FC4 userspace
works - really indistinguishable from my FC4 x86 boxen. The kernel, boot
loader, and anaconda, might be a bit fraught but at the moment it's
really fairly easy (apart from the whole kernel build) to get going
(assuming you can grab an image off a PowerMac). Incidentally, my same
kernel mod allows the Ubuntu 5.04 PowerPC LiveCD to run - which is quite
cool - and I used that to prep the harddisk and "ghost" FC4 onto my
second PegII machine.

Cheers
Richard 


On Mon, 2005-07-18 at 07:41 -0400, David Woodhouse wrote:
> On Mon, 2005-07-18 at 10:26 +0800, RChan wrote:
> > While Pegasos II is not officially support as a PPC platform, some
> > minor kernel tweaks would make it more friendly out-of-the-box for
> > Pegasos II hackers. Would the maintainers kindly consider the
> > following changes:
> 
> My Pegasos II arrived last week just before I left for the Kernel Summit
> and OLS. Hopefully I'll sort out the kernel for it some time soon after
> I get back -- thanks for the detailed pointers.
> 
> The boot thing is horrid; it'd be very much nicer to work out how to
> make yaboot work instead of having to combine the objects. But we do
> manage to merge the iSeries kernel and initrd, so I'm sure we could do
> that if we really had to.
> 
> -- 
> dwmw2
>