IO-APIC
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IO-APIC (I/O Advanced Programmable Interrupt Controller) is an Intel architecture for dealing with interrupts in multi-processor computer systems. It is implemented by the Intel 82093AA chip and found on all Intel SMP CPU boards.
It is one of several attempts to solve IRQ problems; it should not be confused with ACPI (Advanced Configuration and Power Interface).
It can be a cause of system failure, as some versions of some operating systems do not support it properly. If this is the case, disabling IO-APIC may cure the problem. For Linux, try the 'noapic' kernel parameter; for FreeBSD, the 'hint.apic.0.disabled' kernel environment variable.
In Linux, problems with IO-APIC are one of several causes of error messages concerning "spurious 8259A interrupt: IRQ7.". It is also possible that IO-APIC causes problems with network interfaces based on via-rhine driver, causing a transmission time out. Uniprocessor kernels with APIC enabled can cause spurious interrupts to be generated.
External links
- Intel® 82093AA I/O Advanced Programmable Interrupt Controller (I/O APIC) Datasheet (http://www.intel.com/design/chipsets/datashts/290566.htm)
- Key Benefits of the I/O APIC (http://www.microsoft.com/whdc/system/sysperf/IO-APIC.mspx) Microsoft's explanation of I/O APIC
- Importance of Implementing APIC-Based Interrupt Subsystems on Uniprocessor PCs (http://www.microsoft.com/whdc/system/sysperf/apic.mspx)ca:APIC