Devices are necessary to adhere to a protocol so which the interrupt-ask for (IRQ) traces is usually shared. The PCI bus contains four interrupt lines, INTA# through INTD#, all of which are available to each system. Up to eight PCI equipment share precisely the same IRQ line (INTINA# via INTINH#) https://nathanlabsadvisory.com/aramco-cyber-security-compliance/