On Wednesday 18 October 2006 18:24, Dave Jones wrote: > 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. acpi_lapic isn't related to the problem at hand -- that smp_found_config is not set. That said, allowing acpi_lapic=1 to bail out of this check has the sole function of allowing SMP/PIC configurations. (smp_found_config in ACPI mode is set if acpi_lapic and acpi_ioapic are set) SMP/PIC configurations are not very interesting, except for debugging. Indeed, MPS prohibits them by mandating an IOAPIC be present for SMP -- but ACPI has no such rule. -Len - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
