Hello,
On Thu, Apr 03, 2025 at 12:31:37PM +0300, Ilpo Järvinen wrote:
> PCI resource fitting code in __assign_resources_sorted() runs in
> multiple steps. A resource that was successfully assigned may have to
> be released before the next step attempts assignment again. The
> assign+release cycle is destructive to a start-aligned struct resource
> (bridge window or IOV resource) because the start field is overwritten
> with the real address when the resource got assigned.
>
> Properly restore the resource after releasing it. The start, end, and
> flags fields must be stored into the related struct pci_dev_resource in
> order to be able to restore the resource to its original state.
>
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Fixes: 96336ec70264 ("PCI: Perform reset_resource() and build fail list in sync")
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
I've tested this on Orange Pi 5+ where it fixed a regression, too.
Tested-by: Ondrej Jirman <megi@xxxxxx>
Thank you,
Ondrej
> ---
> drivers/pci/setup-bus.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
>
> base-commit: 7d06015d936c861160803e020f68f413b5c3cd9d
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 54d6f4fa3ce1..e994c546422c 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -187,6 +187,9 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
> panic("%s: kzalloc() failed!\n", __func__);
> tmp->res = r;
> tmp->dev = dev;
> + tmp->start = r->start;
> + tmp->end = r->end;
> + tmp->flags = r->flags;
>
> /* Fallback is smallest one or list is empty */
> n = head;
> @@ -545,6 +548,7 @@ static void __assign_resources_sorted(struct list_head *head,
> pci_dbg(dev, "%s %pR: releasing\n", res_name, res);
>
> release_resource(res);
> + restore_dev_resource(dev_res);
> }
> /* Restore start/end/flags from saved list */
> list_for_each_entry(save_res, &save_head, list)
