Hi,

I'm looking for a little advice (or steering in the right direction) in regards to IOAPICs and how Coreboot manages detection. I have two MCP-55 chipsets just like the nVidia l1_2pvv board.

When I boot Linux under the vendor bios with apic debugging enabled, I can see that I have two IOAPICs-

[ 0.000000] IOAPIC[0]: apic_id 4, version 17, address 0xfec00000, GSI 0-23

[ 0.000000] IOAPIC[1]: apic_id 5, version 17, address 0xb0400000, GSI 24-47

And, when I boot using Coreboot, I have only one-

[ 0.000000] IOAPIC[0]: apic_id 5, version 17, address 0xf4340000, GSI 0-23

Now, I'm sure this output is coming from the MP Table which Linux is reading back.

In mptable.c a lot of the MCP-55 boards share this detection code for building the MP Table. Mine will only enter the if statement for bus_mcp55b.

get_bus_conf();
sbdn = sysconf.sbdn;
m = sysconf.mb;

dev = dev_find_slot(m->bus_mcp55, PCI_DEVFN(sbdn+ 0x1,0));
if (dev) {
res = find_resource(dev, PCI_BASE_ADDRESS_1);
if (res)
smp_write_ioapic(mc, m->apicid_mcp55, 0x11, res->base);

if (m->bus_mcp55b) {
dev = dev_find_slot(m->bus_mcp55b, PCI_DEVFN(m->sbdnb + 0x1,0));
if (dev) {
res = find_resource(dev, PCI_BASE_ADDRESS_1);
if (res)
smp_write_ioapic(mc, m->apicid_mcp55b, 0x11, res->base);

So, my question is - what is responsible for detecting the IOAPICs? Is there some configuration somewhere which I may be missing? Any tips for where to look?

Here's a full output from Coreboot and the Linux kernel(apic=debug show_lapic=all): http://pastebin.com/PMVtt6hU

Here's Linux kernel output from the vendor bios: http://pastebin.com/VscyMxM2 (MPTable @ line 110.)

Thanks in advance!

-Nick