An ACPI BIOS can use the "Operating System Interfaces" method (_OSI) to find out what the operating system supports. Eg. If BIOS AML code includes _OSI("XYZ"), the kernel's AML interpreter can ...
On PCI Express, interrupts are represented with either MSI or inbound interrupt messages (Assert_INTx/Deassert_INTx). The integrated IO-APIC in a given Core IO ...