On Thu, 2013-08-01 at 15:34 +0900, Takao Indoh wrote:

(2013/08/01 6:23), Rafael J. Wysocki wrote:

quoted

On Wednesday, July 31, 2013 03:08:03 PM Bjorn Helgaas wrote:

quoted

[+cc Rafael, linux-acpi]

On Tue, Jul 30, 2013 at 6:35 PM, Takao Indoh [off-list ref] wrote:

quoted

On x86, currently IOMMU initialization run *after* PCI enumeration, but
what you are talking about is that it should be changed so that x86
IOMMU initialization is done *before* PCI enumeration like sparc, right?

Yes.  I don't know whether or when that initialization order will ever
be changed, but I do think we should avoid building more
infrastructure that depends on the current order.

Changing the order is a pretty big deal because it's a lot more than
just the IOMMU.  Basically I think we should be enumerating ACPI
devices, including the IOMMU, before PCI devices, but there's a lot of
legacy involved in that area.  Added Rafael in case he has any
thoughts.

Well, actually, I'm not really familiar with IOMMUs, sorry.

I do think that initializing IOMMU before PCI enumeration would be better,
however.  At least if the ordering should be the same on all architectures,
which I suppose is the case, that's the one I'd choose.

Ok guys. If x86 IOMMU maintainer also thinks changing order is
necessary, maybe I need to give up device reset in kdump kernel and
consider doing it in panic kernel.

Either way, I need bus reset interface to reset devices. Bjorn, could
you review the bus reset patches Alex posted yesterday?

I'll post a non-RFC version today, I've made a couple cleanups, tuned
the delays and rolled in the AER version of secondary bus reset.
Thanks,

Alex