On Wed, Aug 07, 2024 at 11:17:12AM -0400, Stewart Hildebrand wrote:
> Devices with alignment specified will lose their alignment in cases when
> the bridge resources have been released, e.g. due to insufficient bridge
> window size. Restore the alignment.
I guess this fixes a problem when the user has specified
"pci=resource_alignment=..." and we've decided to release and
reallocate a bridge window? Just looking for a bit more concrete
description of what this problem would look like to a user.
> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
> ---
> v2->v3:
> * no change
>
> v1->v2:
> * capitalize subject text
> ---
> drivers/pci/setup-bus.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 23082bc0ca37..ab7510ce6917 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1594,6 +1594,23 @@ static void __pci_bridge_assign_resources(const struct pci_dev *bridge,
> }
> }
>
> +static void restore_child_resource_alignment(struct pci_bus *bus)
> +{
> + struct pci_dev *dev;
> +
> + list_for_each_entry(dev, &bus->devices, bus_list) {
> + struct pci_bus *b;
> +
> + pci_reassigndev_resource_alignment(dev);
> +
> + b = dev->subordinate;
> + if (!b)
> + continue;
> +
> + restore_child_resource_alignment(b);
> + }
> +}
> +
> #define PCI_RES_TYPE_MASK \
> (IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH |\
> IORESOURCE_MEM_64)
> @@ -1648,6 +1665,8 @@ static void pci_bridge_release_resources(struct pci_bus *bus,
> r->start = 0;
> r->flags = 0;
>
> + restore_child_resource_alignment(bus);
> +
> /* Avoiding touch the one without PREF */
> if (type & IORESOURCE_PREFETCH)
> type = IORESOURCE_PREFETCH;
> --
> 2.46.0
>
