[Debian-ppc64-devel] Re: New patch to make linux-2.6 support the ppc64 architecture

[Sven Luther]

On Tue, Aug 16, 2005 at 08:22:32PM +0200, Andreas Jochens wrote:
> Hello Sven,
> 
> On 05-Aug-16 17:10, Sven Luther wrote:
> > On Tue, Aug 16, 2005 at 01:33:02PM +0200, Andreas Jochens wrote:
> > I mean, what are the advantages of your solution over the biarch way ? Right
> > now i see it is duplicated work and incures a performance penalty, which are
> > not counterbalanced by anything positive.
> 
> I tried to build most packages on ppc64 and fixed many ppc64 related
> FTBFS errors (e.g. outdated config.{guess,sub} files, endian issues, 
> 64-bit issues, missing #ifdef __powerpc64__ etc.). 
> 
> Without those fixes, it would not be possible to compile those packages 
> for ppc64, regardless if it is in a biarch setup in 64-bit mode or in a
> native ppc64 setup. I would consider this to be a positive effect also 
> for the biarch approach.

Cool.

> Besides, I do not really know how the biarch approach shall work. 
> To really support ppc64 applications you will need to have a 64-bit
> variant for almost every library in the archive. This means that you
> would have to change almost every library package to support biarch.
> The amd64 people thought that they could do this but in the end
> this biarch approach failed.

Yep, we need to have them built once for ppc32 and another time for ppc64.
Those would still be Arch: powerpc, but would install the libraries in /lib64
and stuff, or something such, please look at the libc6-ppc64 where they put
it. I guess we need to do something about the binaries also.

Basically, the biarch setup means we have two systems installed side-by-side.

> I think it will be difficult to change almost every library package
> in the archive and introduce compilicated packaging issues for the
> extra 64-bit builds. It is much easier to use a native ppc64 setup
> and just build the packages as they are. Such an archive already
> exists on alioth with 95% of the packages from 'unstable' compiled.

Which will never be officially part of debian though, and suse, redhat, most
other except gentoo which has not those problems being a source distrib are
doing it this way. You probably won't need all libraries even, only some
critical for 64bit support are needed.

> There is a "multiarch" effort to make it possible to install packages 
> from different architectures on the same system. With this "multiarch" 
> setup it would be possible to install the packages from the native
> ppc64 archive on a powerpc installation if it uses the new 64-bit 
> kernel.

Yep, i have some doubt about its maturity for the etch timeframe though, but
we will see. Right now the focus is on biarch.

> Anyway, the patch to support the native ppc64 kernel is very simple.
> It adds only 8 lines and two symlinks to the linux-2.6 package. Please 
> make things a little easier for me and for the native ppc64 archive by 
> applying the patch.

Yeah, well, nobody in the kernel team is convinced by your approach, so i am
not really sure we want to to support it, but you are free to try convincing
us again :).

> > > Please also consider to set CONFIG_THERM_PM72=y in the config file.
> > > Otherwise PowerMac G5 machines will become very noisy when using the
> > > ppc64 kernel.
> > 
> > Ok, 2.6.12-4 went into unstable without that, but we will fix this in -5. I
> 
> Thanks!

Should be in -5, hopefully uploaded already or coming soon.

Friendly,

Sven Luther