[PATCH] PCI/MSI: pci-xgene-msi: Enable MSI support in ACPI boot for X-Gene v1

[jcm@redhat.com (Jon Masters)]

On 06/03/2016 06:15 PM, Duc Dang wrote:

> Do you have other suggestions? Otherwise, I will prepare a patch
> following Lorenzo's approach.

Duc has since left Applied for other pastures. I miss him, he's a great
guy. He laid all the right groundwork for this, but the ACPI binding
still needs to be upstreamed. It's a few lines of code matching on
APMC0D0E but without it, upstream kernels wont have working MSI on
X-Gene with ACPI. I need this to be upstreamed soon please :) Can
someone at APM followup with an updated patch, and get it in?

Here's the rub. The average person booting a Linux box (even a good
kernel person) isn't going to say "hey, MSIs aren't setup right on this
ARM server because it's compliant with 1 out of 3 possible ways MSIs
might be done at a high level [let's forget the many others] and all it
needs is this...". What they're going to say is "huh, PCIe card doesn't
work, might be an MSI problem". Which is the email I have after someone
tried using an IB card in an X-Gene box and spent a few hours poking.

We're so close to having "ACPI all the things" but the latest
development builds of RHEL don't do MSI on X-Gene because of the Red Hat
"upstream first" rules. So let's get that fixed.

Thanks,

Jon.

-- 
Computer Architect | Sent from my Fedora powered laptop