SMP broken on pre-ACPI machine.

Dave Jones
2006-10-18T22:24:46Z

I've been chasing a bug that got filed against the Fedora kernel
a while back: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=199052
This is a dual pentium pro from an era before we had ACPI, and
it seems to be falling foul of this test in smpboot.c ..

if (!smp_found_config && !acpi_lapic) {
printk(KERN_NOTICE "SMP motherboard not detected.\n");
smpboot_clear_io_apic_irqs();
phys_cpu_present_map = physid_mask_of_physid(0);
if (APIC_init_uniprocessor())
printk(KERN_NOTICE "Local APIC not detected."
" Using dummy APIC emulation.\n");
map_cpu_to_logical_apicid();
cpu_set(0, cpu_sibling_map[0]);
cpu_set(0, cpu_core_map[0]);
return;
}

My initial reaction is that the !acpi_lapic test should be conditional
on some variable that gets set if the ACPI parsing actually succeeded.

Thoughts?