I/O APIC existance

Question about which tools to use, bugs, the best way to implement a function, etc should go here. Don't forget to see if your question is answered in the wiki first! When in doubt post here.
Post Reply
gabor.pap

I/O APIC existance

Post by gabor.pap »

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.
Top
durand
Member
Member
Posts: 193
Joined: Wed Dec 21, 2005 12:00 am
Location: South Africa
Contact:
Contact durand

Re:I/O APIC existance

Post by durand »

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.
Top
User avatar
Brendan
Member
Member
Posts: 8561
Joined: Sat Jan 15, 2005 12:00 am
Location: At his keyboard!
Contact:
Contact Brendan

Re:I/O APIC existance

Post by Brendan »

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
For all things; perfection is, and will always remain, impossible to achieve in practice. However; by striving for perfection we create things that are as perfect as practically possible. Let the pursuit of perfection be our guide.
Top
gabor.pap

Re:I/O APIC existance

Post by gabor.pap »

Thanks for your help!
I'll dig into the ACPI specs... :)
Top
Post Reply

Return to “OS Development”