Re: [PATCH V6] PCI: Add support for preserving boot configuration

Bjorn Helgaas
2024-04-21T19:03:26Z

On Thu, Apr 18, 2024 at 11:10:43PM +0530, Vidya Sagar wrote:
> Add support for preserving the boot configuration done by the
> platform firmware per host bridge basis, based on the presence of
> 'linux,pci-probe-only' property in the respective PCI host bridge
> device-tree node. It also unifies the ACPI and DT based boot flows
> in this regard.

This looks great; my only comments are:

- It might make sense to move the _DSM evaluation to pci-acpi.c
instead of probe.c.

- There are a few different things going on (move _DSM, look at DT
host bridge in addition to of_chosen, integrate ACPI and DT flows,
tweak usage of PCI_PROBE_ONLY vs bridge->preserve_config, use
pci_assign_unassigned_root_bus_resources() when we didn't before),
and I think they could be split into multiple patches to make it
easier to read.

I took a stab at splitting this, but didn't quite complete it. I'll
post that as v7-incomplete, and if you compare with v6, you'll see
what's missing (the PCI_PROBE_ONLY and assign resources stuff --
there's some subtlety there that wasn't obvious to me).

Bjorn