On Wed, Mar 22, 2017 at 06:33:24PM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@xxxxxxx>
>
> The function acpi_bus_attach() creates platform_devices if
> this is specified by the firmware. But in acpi_bus_trim()
> these devices are not removed, leaving a dangling reference
> to the parent device.
>
> In the case of a PCI root-bus, this results in the
> host_bridge device not being released on hot-remove.
>
> Fix it by scanning the list of platform_devices for devices
> to be removed with the bus.
>
> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
> ---
> drivers/acpi/scan.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 1926918..b07518b 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -13,6 +13,7 @@
> #include <linux/dmi.h>
> #include <linux/nls.h>
> #include <linux/dma-mapping.h>
> +#include <linux/platform_device.h>
>
> #include <asm/pgtable.h>
>
> @@ -1928,6 +1929,25 @@ int acpi_bus_scan(acpi_handle handle)
> EXPORT_SYMBOL(acpi_bus_scan);
>
> /**
> + * acpi_bus_trim_platform_device - Check and remove a platform device
> + * from a bus
> + * @dev: Platform device to check
> + * @data: pointer to the acpi_device to check dev against
> + *
> + * Checks whether the platform_device dev belongs to the acpi_device
> + * data and unregisters dev if it matches.
> + */
> +static int acpi_bus_trim_platform_device(struct device *dev, void *data)
> +{
> + struct acpi_device *adev = data;
> +
> + if (dev->fwnode == acpi_fwnode_handle(adev))
> + platform_device_unregister(to_platform_device(dev));
> +
> + return 0;
> +}
> +
> +/**
> * acpi_bus_trim - Detach scan handlers and drivers from ACPI device objects.
> * @adev: Root of the ACPI namespace scope to walk.
> *
> @@ -1950,6 +1970,12 @@ void acpi_bus_trim(struct acpi_device *adev)
> } else {
> device_release_driver(&adev->dev);
> }
> +
> + /* Remove platform devices from the bus */
> + if (adev->pnp.type.platform_id)
This patch cases that dock_notify() is broken in find_dock_station()
because the dock_station platform device was removed.
If anyone wants to apply this patch, then the dock device should be
excluded:
+ if (is_dock_device(adev) && adev->pnp.type.platform_id)
> + bus_for_each_dev(&platform_bus_type, NULL, adev,
> + acpi_bus_trim_platform_device);
> +
> /*
> * Most likely, the device is going away, so put it into D3cold before
> * that.
Thanks a lot!
Joey Lee
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