[RFC PATCH 0/2] Allow reusing PCI domain numbers in DT

[Cui Chao]

This series allows multiple PCIe host bridges to reuse the same software
domain number in Device Tree (DT), provided their resources are disjoint.

In mainstream GPU P2P functionality, whether the GPUs participating in
P2P belong to the same PCIe domain is one of the decision criteria. In
the existing DT path, a uniqueness constraint is imposed on the PCI
domains of multiple PCIe nodes, which prevents devices under different
PCIe RCs from reusing the same software domain number.

It should be noted that equality of PCI domains at the software level
is not equivalent to the final P2P decision. The ACPI path directly
returns '_SEG' and does not perform a similar uniqueness check, as
'_SEG' is a purely software concept and allows multiple RCs to use the
same value.

Cui Chao (2):
  dt-bindings: PCI: Add linux,pci-domain-reuse property
  PCI: Allow reusing PCI domain numbers in DT

 .../devicetree/bindings/pci/host-generic-pci.yaml  | 10 ++++++++++
 drivers/pci/pci.c                                  | 14 ++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

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2.33.0