Re: [PATCH] Fix not loading acpi-cpufreq driver regression

[Thomas Renninger <trenn@suse.de>]

On Monday, June 25, 2012 01:00:10 PM Thomas Renninger wrote:
> ACPI processor: Only blindly return apic id 0 for real UP systems
> 
> This fixes a "not loading acpi-cpufreq driver" regression introduced
> by git commit d640113fe80e45ebd4a5b4 on SMP systems where the processor
> core with ACPI id zero is disabled
> (typically should be the case because of hyperthreading).
> The regression got spread through stable kernels.
> On 3.0.X it got introduced via 3.0.18.
> 
> Such platforms may be rare, but do exist. This problem has been
> observed on a:
> HP Proliant BL280c G6 blade
> This patch restricts the introduced workaround to platforms
> with nr_cpu_ids <= 1.

Wallak:
Can you give this patch a try and double check whether things still
work for you.
If I understand it correctly you tried a UP compiled kernel?
On this one I expect nr_cpu_ids to be statically set to 1 and the
patch should be fine for you.

The only other candidate I can think of which needs this,
are platforms with only 1 core available and no SMP APIC/ACPI mapping 
table, but a
Processor (...)
ACPI object.
Those should also still be covered with my patch.

Thanks,

   Thomas