Re: Bug#440720: [SPARC]: non-SMP kernel fail on SunFIres with >= 2 CPUs
Bernd Zeimetz <firstname.lastname@example.org> writes:
>> Looks like we need to discuss the available options for this
>> problem. Other issue is to know if current snapshots of 2.6.23 does
>> work or not on this hardware.
>> Bernd, can you test lastest 2.6.23 snapshot and see if it works? Check
>> at http://wiki.debian.org/DebianKernel for more information where to
>> find them.
> I've installed the machine using a 2.6.23-rc5 _smp_ kernel, all older
> non-smp kernels failed to boot, and as Ihad to build my own installer
> and kernel anyway I've decided to use an smp version.
Have you tested it witn a non-smp kernel?
> As it takes a _long_ time to reboot a machine with a "crashed" CPU
> (which was the result of all non-SMP kernel tests so far), and the
> machine should be in production yet, I would like to avoid to try a
> non-smp kernel on this machine.
Right. It makes difficult to us to know if has or not been fixed since
your last try.
> I've looked trough the sparc64 commits (about 80) between 2.6.22 and
> 2.6.23-rc6 and there was non which looked like it would address such an
> issue. If you can point me to such a change I'll give a non-smp kernel a
> Also I'm pretty sure that non-smp kernels just don't work on the
> machine. As far as I understand the way those machines work is that at
> least two CPUs have to be in an operating state as they share one CPU
> Data switch (if you have a look into such a machine you see that always
> 2 CPUs + their memory are sitting in a CPU bay, and as far as I know you
> can't run the system with an odd number of CPUs.
> All processors share the same pysical memory address space and use -
> depending on the number of CPUs - different cache coherence protocols,
> so as far as I understand it such a system can't work at all without
> having all CPUs properly initialized. But probably somebody with a
> better knowledge about this architecture can give us some insight on
> that, therefore I'm forwarding the message to debian-sparc, too.
> Probably interesting to read for you:
If that's true then we might have two options:
- add a subarch for sparc with the needed kernel changes for it;
- change default kernel on installer to be smp;
What other think about that? (added debian-boot on cc due this)
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