Re: [PATCH] ACPI: boot correctly with "nosmp" or "maxcpus=0"

From: Andi Kleen
Date: Thu Aug 16 2007 - 14:43:01 EST


> @@ -157,10 +162,13 @@ early_param("nosmp", nosmp);
> static int __init maxcpus(char *str)
> {
> get_option(&str, &max_cpus);
> - return 1;
> + if (max_cpus == 0)
> + disable_ioapic_setup();

I must say I never liked that maxcpus=0 ... does disable the APIC
too. There can be situations where you want only a single CPU,
but still full APICs because modern systems don't boot without.

It's the old traditional documented semantics though,
but on the other hand if it never worked with ACPI i guess people are
not relying on it.

So perhaps it would be better to change that?
Or add a new option to limit CPUs without disabling ACPIC?

-Andi
-
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