Re: [PATCH v18 11/13] PCI: Cache PCI DSN into pci_dev->dsn during probe

[Lukas Wunner]

On Fri, Jul 17, 2026 at 05:27:04PM -0500, Terry Bowman wrote:
> Add a u64 dsn field to struct pci_dev and populate it from pci_get_dsn()
> during pci_init_capabilities() at probe time via pci_dsn_init(). Only
> write dev->dsn when the read succeeds. The zero initial value from
> pci_dev allocation already represents 'no DSN available.'

The DSN is already cached on (natively handled) PCIe hotplug ports
to detect device replacement during system sleep, see struct controller
in drivers/pci/hotplug/pciehp.h.

Please remove that member from struct controller, remove the two
assignments to the member in pciehp_configure_device() and pcie_init()
and change the comparison in pciehp_device_replaced() to use the new
member in struct pci_dev.  You can do this either as part of this patch
or in a separate patch.

Thanks,

Lukas