Units Are required to follow a protocol so which the interrupt-request (IRQ) strains is usually shared. The PCI bus incorporates four interrupt strains, INTA# via INTD#, all of which are available to every machine. Nearly 8 PCI devices share the identical IRQ line (INTINA# by way of INTINH#) in APIC-enabled https://nathanlabsadvisory.com/adhics-compliance/