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I wonder if there is another (and of course reliable) way to find out if there is IOAPIC on the board than finding the MP structure?
On mine (NF2 board) I couldn't find the _MP_ signature, yet there is an IOAPIC, which I tested by reading it's version no.

Testing for the version number is the correct way to do it. If it's there, then the IO APIC is there. That's all you need to do.

Hi,

The normal way is to parse the ACPI boot tables (and/or the MP specification tables). If both ACPI and MP aren't present, then it's likely that the motherboard doesn't handle things properly anyway.

durand wrote:Testing for the version number is the correct way to do it. If it's there, then the IO APIC is there. That's all you need to do.

For probing, I'd probably be a little more thorough - see if the version number is read only, and if the APIC ID is read/write....


Cheers,

Brendan

Thanks for your help!
I'll dig into the ACPI specs...