Bryce,

Here is how I fixed it. Please search for "~cpw" to find my comments
(three of them). I stumbled across the bug with a chipset whose PCI
bridge is a multifunction device.

Best regards,
Chih-Pin Wu

************************************************************* 
Extracted from common_bridge.c, libpciaccess 0.12.0

int
pci_device_get_bridge_buses(struct pci_device * dev, int *primary_bus,
			    int *secondary_bus, int *subordinate_bus)
{
    struct pci_device_private * priv = (struct pci_device_private *)
dev;

    /* If the device isn't a bridge, return an error.
     */
    
    if (((dev->device_class >> 16) & 0x0ff) != 0x06) {
	return ENODEV;
    }
//~cpw Removed the following three statements
//     priv->bridge.pci is invalid since it is initialized to null;
//     As a result, the function always returns ENODEV.
//
//    if (!priv->bridge.pci) {
//	return ENODEV;
//    }

    switch ((dev->device_class >> 8) & 0x0ff) {
    case 0x00:
	/* What to do for host bridges?  I'm pretty sure this isn't
right.
	 */
	*primary_bus = dev->bus;
	*secondary_bus = -1;
	*subordinate_bus = -1;
	break;

    case 0x01:
    case 0x02:
    case 0x03:
	*primary_bus = dev->bus;
	*secondary_bus = -1;
	*subordinate_bus = -1;
	break;

    case 0x04:
    if (priv->bridge.pci == NULL)
        read_bridge_info(priv);

//~cpw Mask bit7 of header type since it is a multi-function device
//     indicator; Bridge itself could be a multi-function device and
//     the comparison should be against 0x01 and 0x81
//    if (priv->header_type == 0x01) {
    if ((priv->header_type & 0x7f) == 0x01) {
	*primary_bus = priv->bridge.pci->primary_bus;
	*secondary_bus = priv->bridge.pci->secondary_bus;
	*subordinate_bus = priv->bridge.pci->subordinate_bus;
    } else {
	*primary_bus = dev->bus;
	*secondary_bus = -1;
	*subordinate_bus = -1;
    }
	break;

    case 0x07:
    if (priv->bridge.pcmcia == NULL)
        read_bridge_info(priv);
//~cpw Mask bit7 of header type since it is a multi-function device
//     indicator; Bridge itself could be a multi-function device and
//     the comparison should be against 0x02 and 0x82
//    if (priv->header_type == 0x02) {
    if ((priv->header_type & 0x7f) == 0x02) {
	*primary_bus = priv->bridge.pcmcia->primary_bus;
	*secondary_bus = priv->bridge.pcmcia->card_bus;
	*subordinate_bus = priv->bridge.pcmcia->subordinate_bus;
    } else {
	*primary_bus = dev->bus;
	*secondary_bus = -1;
	*subordinate_bus = -1;
    }
	break;
    }

    return 0;
}


-----Original Message-----
From: <email address hidden> [mailto:<email address hidden>] On Behalf Of
Bryce Harrington
Sent: Friday, November 26, 2010 4:52 PM
To: Chihpin Wu
Subject: [Bug 681207] Re: PCI device header type doesn't include bit7

Hi chihpinwu, thanks for reporting this issue.  I don't think there's
been a lot of testing with multi-function cards so this may have gone
untested.  I'm a bit uncertain how this should be fixed - would you be
willing to suggest a patch?


** Changed in: libpciaccess (Ubuntu)
       Status: New => Triaged

** Changed in: libpciaccess (Ubuntu)
   Importance: Undecided => Medium

** Changed in: libpciaccess (Ubuntu)
     Assignee: (unassigned) => Bryce Harrington (bryce)

-- 
PCI device header type doesn't include bit7
https://bugs.launchpad.net/bugs/681207
You received this bug notification because you are a direct subscriber
of the bug.

Status in "libpciaccess" package in Ubuntu: Triaged

Bug description:
Within the function pci_device_get_bridge_buses() in file
common_bridge.c, "priiv->header_type" is used to detect the bridge type
without bit 7 (indicating multi-function or not) stripped. As a result
the detection would always fail for multi-function card. I see this
error in both versions 0.10.6 and 0.12.0.

Beside this problem, version 0.12.0 has a pointer check
"priv->bridge.pci" upon fuction entrance and just return "ENODEV" if it
is null. The problem is that the pointer never got initialized in the
first place and will always be null. This checking should be removed.

To unsubscribe from this bug, go to:
https://bugs.launchpad.net/ubuntu/+source/libpciaccess/+bug/681207/+subs
cribe