Devices are required to comply with a protocol so that the interrupt-ask for (IRQ) lines can be shared. The PCI bus consists of four interrupt strains, INTA# by means of INTD#, all of which are offered to each device. As much as 8 PCI devices share precisely the same IRQ https://nathanlabsadvisory.com/maximize-business-trust-and-security-with-hitrust-compliance/