HP Workstation x1000 hp workstation x1000 - technical reference guide - Page 75

PCI IRQ lines

Page 75 highlights

NOTE system board assigned device interrupts virtual wire mode allows the transition to the symmetric I/O mode. In the virtual wire mode, only one processor executes instructions. • Symmetric I/O mode: This mode is implemented with APIC controllers in the ICH2 and P64H and allows for multiple processor operations. In PIC mode and virtual wire mode, PCI interrupts are routed to the INT line. In symmetric I/O mode, PCI interrupts are routed to the I/O APIC controllers and forwarded over an APIC bus to the processors. PCI IRQ lines PCI devices generate IRQs using up to four PCI IRQ lines (INTA#, INTB#, INTC#, and INTD#). PCI interrupts can be shared; several devices can use the same interrupt. However, optimal system performance is reached when minimizing the sharing of interrupts. Refer to page 73 for a table of the PCI device interrupts. Chapter 2 75

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system board
assigned device interrupts
Chapter 2
75
virtual wire mode allows the transition to the symmetric I/O mode. In
the virtual wire mode, only one processor executes instructions.
Symmetric
I/O
mode
:
This
mode
is
implemented
with
APIC
controllers in the ICH2 and P64H and allows for multiple processor
operations.
NOTE
In PIC mode and virtual wire mode, PCI interrupts are routed to the INT
line. In symmetric I/O mode, PCI interrupts are routed to the I/O APIC
controllers and forwarded over an APIC bus to the processors.
PCI IRQ lines
PCI devices generate IRQs using up to four PCI IRQ lines (INTA#,
INTB#, INTC#, and INTD#).
PCI
interrupts
can
be
shared;
several
devices
can
use
the
same
interrupt.
However,
optimal
system
performance
is
reached
when
minimizing the sharing of interrupts. Refer to page 73 for a table of the
PCI device interrupts.