On Thu, Aug 06, 2026 at 09:28:03PM +0200, Rafael J. Wysocki wrote:
> If acpi_dev_get_resources() returns overlapping I/O or memory resources,
> the subsequent registration of a platform device will fail with -EBUSY
> due to a resource conflict. This is reported to happen on Acer Aspire
> ES1-572 [1].
>
> Avoid that by adjusting resources returned by acpi_dev_get_resources()
> to eliminate partial overlaps between them.
>
> This has not been regarded as necessary before because putting
> overlapping resources into the _CRS of one device is really pointless,
> but now that the issue has been reported to actually happen in the
> field, it needs to be done.
...
> +static unsigned int acpi_platform_adjust_resources(struct acpi_device *adev,
> + struct resource *new_res,
> + struct resource *resources,
> + unsigned int count)
> +{
> + unsigned int i;
> +
> + if (!(new_res->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
> + return count;
> +
> + for (i = 0; i < count; ) {
> + struct resource *res = &resources[i];
> +
> + if (resource_type(new_res) != resource_type(res) ||
> + !resource_overlaps(new_res, res)) {
> + i++;
> + continue;
> + }
> +
> + dev_info(&adev->dev, "Adjusting %pR for %pR\n", new_res, res);
> + /*
> + * Extend the new resource to include the one that has been
> processed
> + * already.
> + */
> + if (res->start < new_res->start)
> + new_res->start = res->start;
> +
> + if (res->end > new_res->end)
> + new_res->end = res->end;
Can we use resource_union() instead?
> + /*
> + * Eliminate the previously processed resource that has
> + * triggered the adjustment because it is not necessary any
> + * more.
> + */
> + memmove(res, res + 1, (--count - i) * sizeof(*res));
> + }
> +
> + return count;
> +}
--
With Best Regards,
Andy Shevchenko
