Re: [PATCH v2 2/3] PCI: Configure Root Port MPS after scanning its hierarchy

[sashiko-bot@kernel.org]

> With the default MPS strategy (PCIE_BUS_DEFAULT), pci_configure_mps()
> only matches each device's Maximum Payload Size (MPS) to its upstream
> bridge.  Root Ports have no upstream bridge, so their MPS stays at
> whatever firmware or the hardware default (128 bytes) left there, and the
> hierarchy below them inherits that value even if the Root Port and all
> devices below it support more.
> 
> Once the hierarchy below a Root Port has been scanned, and before drivers
> are bound, set the Root Port and every device below it to the largest MPS
> they all support, even if that is more than firmware programmed.  Do this
> from pcie_bus_configure_settings(), which the host bridge, ACPI and
> hotplug paths call after scanning, and from pci_rescan_bus() and
> pci_rescan_bus_bridge_resize(), which don't.
> 
> If the hierarchy contains a hotplug bridge other than the Root Port,
> [ ... ]
> 
> Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
> Co-developed-by: Hans Zhang <18255117159@163.com>
> Signed-off-by: Hans Zhang <18255117159@163.com>
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Sashiko has reviewed this patch and found no issues.

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