XT-PIC vs. IO-APIC-edge vs. IO-APIC-level
 

:newbie: I have a two-fold question

[Q#1]: I'm starting my Redhead v3.0 (kernel 2.4.21-4) in "apic" mode. I noticed 3 different level of INTERRUPTS:
-> XT-PIC
-> IO-APIC-EDGE
-> IO-APIC-Level

So what is the basic difference between these methods?


[Q#2]: The answer to Q#1 might already answer this question, but I've got to ask it anyway ...

So, if all 3 methods (XT-PIC, IO-APIC-EDGE and IO-APCIC-Level) are present in the system, what does the INTERRUPT handling look like? What INT is scheduled first, if interrupts of all 3 groups are pending/present? Is there some form of INT-nesting/pre-emption going on, of one or the other group?


Thanks,
Peps
04/19/04