Need help for pci/pcie driver configuration for interrupt

Question

Hi I am writing driver for openserver-6 SCO operating system for serial PCI/PCIe cards using DDI8 mp interface. I am facing problem while getting interrupt on PCIe cards.Though driver working properly on PCI cards.Is there any different configuration required for PCIe cards?

Answer 1

PCIe has two different mechanisms for interrupt.: 1. Legacy interrupts. Those are signalled by the device thought INTx messages. These are sometime referred to as level-triggered interrupt as they virtually reproduce the PCI legacy 2. Message signaled interrupts(MSI) and their extension (MSI-X). Those are signalled by MWr packets at host specific address.

You can tell which mode is use by looking at the device configuration space. If you have pciutils available on your platform, lspci -vvv will dump it for you.