[PATCH v3 0/4] x86/PCI: Improve $PIR and add $IRT PIRQ routing support

From: Maciej W. Rozycki
Date: Thu Jan 06 2022 - 06:24:05 EST


Hi,

This is a new patch series made around a discrete patch submitted earlier
on that has gone nowhere, which is now 1/4. That change handles $PIR PIRQ
routing tables that lack router device information, fixing the inability
to route interrupts with a system using the SiS85C497 ISA bridge. It has
been minimally updated from v1 by including router device information
reported with the change description, and by adding Nikolai's Tested-by
annotation.

Then 2/4 adds support for the $IRT PIRQ routing table format invented by
AMI before Microsoft has come up with its own $PIR format. These formats
are very similar to each other, but the $IRT format does not provide for
router device information, so this change relies on 1/4. It has turned
out needed to route interrupts with a system using the ALi M1487 ISA Bus
Controller device, discussed earlier on in a discussion thread around:
<https://lore.kernel.org/linux-pci/61377A45.8030003@xxxxxxxxx/>. This
change has been verified with an artificially created $IRT table and
hopefully Nikolai will be able to verify this code with his system as
well.

Then 3/4 corrects our link value interpretation for said M1487 device
according to Nikolai's findings with his system reported here:
<https://lore.kernel.org/linux-pci/61428EDF.9030203@xxxxxxxxx/>.

Finally 4/4 corrects a couple of coding style issues around though not
immediately within code changed by 2/4 so as to make the style consistent.

See individual change descriptions for further details.

Credit to Michal (cc-ed) for helping me chase documentation for the
$IRT table format.

Please apply.

Maciej