If you run 'pci -v' you will see all of the capabilities for all of the devices. The MSI or MSIX interrupt is only assigned once a pci_attach_device() has been performed, so if there is no driver running against a MSI or MSIX capable device, you will see the standard IRQ interrupt. See the attached pci.txt file where the gigabit Ethernet device has been assigned MSIX interrupts.

Hugh Brown

QNX Software Systems Limited

1001 Farrar Rd.,

Ottawa. ON. K2K 0B3.

Telephone: 613-591-0931

From: Armin Steinhoff <community-noreply@qnx.com>
Reply-To: "general-community@community.qnx.com" <general-community@community.qnx.com>
Date: Wednesday, 4 July, 2012 2:33 PM
To: "general-community@community.qnx.com" <general-community@community.qnx.com>
Cc: Info System - IS Notifications <is-notifications@qnx.com>, Info System - IS Notifications <is-notifications@qnx.com>, Info System - IS Notifications <is-notifications@qnx.com>, Info System - IS Notifications <is-notifications@qnx.com>
Subject: Re: PCI Express

Hugh Brown wrote:

The PCI server enables either the MSI or MSIX capability depending on
which is selected and also assigns MSI/X IRQ numbers to the device. Is
this what you are talking about?

Yes and No.
From the example provided by the pci_attach_device documentation:

if (pci_read_config8 (bus, devfn, cap_ptr, 1, &cap)) <<<--- that means the OS must set the capabilities before
                                                                                 <<<--- but in the dumps of pci or lspci I saw
                                                                                 <<<--- never entries of the MSI capabilities of PCIe devices
    return (-1);
if (cap == PCI_CAP_MSI)

The assigned IRQ seems alway connected to an INTx line ... which is the default non MSI mapping.

Regards

--Armin