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011496bda0
The DSDT must declare the interrupt used by the serial device. This helps the guest kernel matching the right interrupt to the 8250 serial device. This is mandatory in case the IRQ routing is handled by ACPI, as we must let ACPI know what do do with pin based interrupts. One thing to notice, if we were using acpi=noirq from the kernel command line, this would mean ACPI is not in charge of the IRQ routing, and the device COM1 declaration would not be needed. One additional requirement is to provide the appropriate interrupt source override for the legacy ISA interrupts (0-15), which will give the right information to the guest kernel about how to allocate the associated IRQs. Because we want to keep the MADT as simple as possible, and given that our only device requiring pin based interrupt is the serial device, we choose to only define the pin 4. Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>