Regression in 8.2-STABLE bge code (from 7.4-STABLE)

John Baldwin jhb at
Fri Feb 24 17:54:37 UTC 2012

On Tuesday, February 14, 2012 7:56:00 pm YongHyeon PYUN wrote:
> On Sat, Jan 28, 2012 at 09:24:53PM -0500, Michael L. Squires wrote:
> Sorry for late reply.  Had been busy due to relocation.
> > There is a bug in the Tyan S4881/S4882 PCI-X bridges that was fixed with a 
> > patch in 7.x (thank you very much).  This patch is not present in the 
> > 8.2-STABLE code and the symptoms (watchdog timeouts) have recurred.
> > 
> Hmm, I thought the mailbox reordering bug was avoided by limiting
> DMA address space to 32bits but it seems it was not right workaround
> for AMD 8131 PCI-X Bridge.
> > The watchdog timeouts do not appear to be present after I switched to an 
> > Intel gigabit PCI-X card.
> > 
> > I did a brute-force patch of the 8.2-STABLE bge code using the patches for
> > 7.4-STABLE; the resulting code compiled and, other than odd behavior at
> > startup, seems to be working normally.
> > 
> > This is using FreeBSD 8.2-STABLE amd64; I don't know what happens with 
> > i386.
> > 
> > Given the age of the boards it may be easier if I just continue using the
> > Intel gigabit card but am happy to test anything that comes my way.
> > 
> Try attached patch and let me know how it goes.
> I didn't enable 64bit DMA addressing though. I think the AMD-8131
> PCI-X bridge needs both workarounds.

Eh, please don't do the thing where you walk all pcib devices.  Instead, walk 
up the tree like so:

static int
bge_mbox_reorder(struct bge_softc *sc)
	devclass_t pcib, pci;
	device_t dev, bus;

	pci = devclass_find("pci");
	pcib = devclass_find("pcib");
	dev = sc->dev;
	bus = device_get_parent(dev);
	for (;;) {
		dev = device_get_parent(bus);
		bus = device_get_parent(dev);
		if (device_get_devclass(dev) != pcib_devclass ||
		    device_get_devclass(bus) != pci_devclass)
		/* Probe device ID. */
	return (0);

It is not safe to use pci_get_vendor() with non-PCI devices (you may get
random junk, and Host-PCI bridges are not PCI devices).  Also, this will only
apply the quirk if a relevant bridge is in the bge device's path.

John Baldwin

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