Re: [PATCH] PCI: Fix PCIe SBR dev/link wait error

[Lukas Wunner <lukas@wunner.de>]

On Tue, Nov 25, 2025 at 02:20:10PM +0800, guanghui.fgh wrote:
> After __pci_reset_slot/__pci_reset_bus calls
> pci_bridge_wait_for_secondary_bus, the device will be restored via
> pci_dev_restore. However, when a multifunction PCIe device is connected,
> executing pci_bridge_wait_for_secondary_bus only guarantees the restoration
> of a random device. For other devices that are still restoring, executing
> pci_dev_restore cannot restore the device state normally, resulting in
> errors or even device offline.

PCIe is point-to-point, i.e. at the two ends of a link there's only a
single physical device.  So if there are multiple pci_dev's on a bus,
they're additional functions or VFs of the same physical device.

The expectation is that if the first device on the bus is accessible,
all other functions of the same physical device are accessible as well.
That's why we only wait for the first device to become accessible.

It seems highly unusual that the different functions of the same physical
device require different delays until they're accessible.  I don't think
we can accept such a sweeping change wholesale without more details,
so please share what the topology looks like (lspci -tv), what devices are
involved (lspci -vvv) and which device requires extra wait time for some
of its functions.

Thanks,

Lukas