Hugh,

I have hier the same PCI Express board placed in an other slot. There are not the MSI capabilitie set,
but a MSI interrupt of 18 has been assigned. The crazy point is: the board is working in default mode with that IRQ!

09:04.0 Unassigned class [ff00]: PLX Technology, Inc. Device 86e1 (rev ac)
    Subsystem: SOFTING GmBH Device 002b
    Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
    Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
    Latency: 32, Cache Line Size: 64 bytes
    Interrupt: pin A routed to IRQ 18
    Region 0: Memory at 55480000 (32-bit, non-prefetchable)
    Region 1: I/O ports at 3000
    Region 2: Memory at 55400000 (32-bit, non-prefetchable)
    Capabilities: [40] Power Management version 0    <<<<=== no MSI caps !
        Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
        Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
    Capabilities: [48] CompactPCI hot-swap <?> <<<=== wrong!
    Capabilities: [4c] Vital Product Data
        Not readable
00: b5 10 e1 86 17 00 b0 02 ac 00 00 ff 10 20 00 00     <<< dump of the config space
10: 00 00 48 55 01 30 00 00 00 00 40 55 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 a0 14 2b 00
30: 00 00 00 00 40 00 00 00 00 00 00 00 12 01 00 00

Regards

--Armin



Hugh Brown wrote:
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