On Mon, 2013-02-04 at 10:36 -0800, Stephen Hemminger wrote:
> > I think drivers/pci/search.c is identical between 3.7 and 3.8-rc1. Is
> > this the first time you've turned on the IOMMU on that box?
>
> It exists in 3.7 and earlier kernels, just haven't turned on same config.
>
> > It's the same warning as in this bugzilla:
> > https://bugzilla.kernel.org/show_bug.cgi?id=44881, and there's a patch
> > there at https://bugzilla.kernel.org/show_bug.cgi?id=44881#c11, but
> > it's just a quirk that turns off VT-d if we find certain broken
> > bridges. It doesn't look like you have any of those (although I don't
> > know what you have at 05:00.0).
> >
> > Bjorn
>
> This is a standard ASUS motherboard, and don't want to disable VT-d.
Stephen,
Can you give the lspci -vvv of device 5:00.0 to see if it's one we've
seen before? Does the patch below help?
Bjorn, I think we need to quirk it somehow. So far they've all been
PCI-to-PCI bridges attached to root ports where we expect it's actually
a PCIe-to-PCI bridge. Seems like maybe we could have the same attached
to a downstream port. The patch below avoids the WARN and gives us a
device, but of course pci_is_pcie reports wrong for this device and may
cause some trickle down breakage. A more complete option might be to
add a is_pcie flag to the device that can be set independent of
pcie_cap. We'd need to check all the callers for assumptions, but then
we could put the quirk in one place and hopefully fix everything.
Thoughts? Thanks,
Alex
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index bf969ba..65ae270 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -42,6 +42,15 @@ pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
}
/* PCI device should connect to a PCIe bridge */
if (pci_pcie_type(pdev) != PCI_EXP_TYPE_PCI_BRIDGE) {
+ /*
+ * Not all PCIe-to-PCI bridges expose a PCIe
+ * capability. If we make it to a PCIe root port
+ * and the previous device was a PCI-to-PCI bridge,
+ * assume it was really a PCIe-to-PCI bridge.
+ */
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
+ tmp && tmp->hdr_type == PCI_HEADER_TYPE_BRIDGE)
+ return tmp;
/* Busted hardware? */
WARN_ON_ONCE(1);
return NULL;
_______________________________________________
iommu mailing list
[email protected]
https://lists.linuxfoundation.org/mailman/listinfo/iommu
