Re: [PATCH v9] irq: add quirk for broken interrupt remapping on 55XX chipsets

[Joerg Roedel <joro@8bytes.org>]

On Tue, Apr 16, 2013 at 09:35:56AM -0400, Neil Horman wrote:
> Actually, hold on that last note, the intel iommu init code doesn't seem to
> create any direct relationship between the set of iommu's and the pci_dev's that
> implement them.  In the intel_irq_remapping_supported path I can loop over each
> dmar_dhrd_unit, and interrogate each of the devices on its **devices list to see
> if the device/vendor and revision ids match, but looking at the dhrd parsing
> code, I'm not sure the iommu pci_dev is always going to be on that list.  That
> seems like its going to be pretty ugly in and of itself.  Do you have a
> suggested way to identify the pci_dev of the device we need in that path without
> having to simply iterate over every device in that scope?

Hmkay, looks like this is a non-trivial problem. Here is what I suggest:
Keep the early-quirk as in your current patch. But add a function to
drivers/iommu/irq_remapping.c to disable irq-remapping and export that
function via the header-file arch/x86/include/asm/irq_remapping.h. Use
that function in the quirk instead of setting the disable-flag directly.
This way you don't have to include any private header file from iommu
code.


	Joerg