LAPCI disabled for second Processor in 2.6.8-11-amd64-k8-smp kernel - need help reading source code

Siju George <[email protected]> Wed, 28 Dec 2005 20:41:19 +0530
Newsgroups org.kernel.vger.linux-smp
Message-ID <[email protected]>
Hi,

I need some help to sort out this :-)

The following lines appear in the dmesg of my Dual Opteron Server
running on 2.6.8-11-amd64-k8-smp kernel

--------------
Processor #0 15:5 APIC version 16
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x01] enabled)
Processor #1 15:5 APIC version 16
ACPI: LAPIC (acpi_id[0x03] lapic_id[0x82] disabled)
ACPI: LAPIC (acpi_id[0x04] lapic_id[0x83] disabled)
---------------------------------

What is LAPIC?
Why is it disabled for the second processor?
Is it normal beavior?

I have posted to several mailinglist and got no reply on this :-(

I have traced to the kernel code at

http://fxr.watson.org/fxr/source/drivers/acpi/tables.c?v=linux-2.6.11.8#L121

From lines 121-127 I find this.

-----------------------------
case ACPI_MADT_LAPIC:
         {
                 struct acpi_table_lapic *p =
                         (struct acpi_table_lapic*) header;
                 printk(KERN_INFO PREFIX "LAPIC (acpi_id[0x%02x]
lapic_id[0x%02x] %s)\n",
                         p->acpi_id, p->id,
p->flags.enabled?"enabled":"disabled");
         }
----------------------------------
Could some one who works on the kernel or who knows C please interpret
this for me?
The code version is differrent but I hope it does not affect.

Please let me know if you need the full dmesg

Thankyou so much :-)

Kind Regards

Siju