On Fri, Jun 28, 2013 at 12:47 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> If there are indirect dependencies between devices in a dock
> station's dependent devices list, they may be broken if the devices
> are removed in the same order in which they have been added.
>
> For this reason, make the code in handle_eject_request() walk the
> list of dependent devices in reverse order.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> drivers/acpi/dock.c | 45 +++++++++++++++++++++++++++++----------------
> 1 file changed, 29 insertions(+), 16 deletions(-)
>
> Index: linux-pm/drivers/acpi/dock.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/dock.c
> +++ linux-pm/drivers/acpi/dock.c
> @@ -396,9 +396,29 @@ static void dock_remove_acpi_device(acpi
> }
>
> /**
> - * hotplug_dock_devices - insert or remove devices on the dock station
> + * hot_remove_dock_devices - Remove dock station devices.
> + * @ds: Dock station.
> + */
> +static void hot_remove_dock_devices(struct dock_station *ds)
> +{
> + struct dock_dependent_device *dd;
> +
> + /*
> + * Walk the list in reverse order so that devices that have been added
> + * last are removed first (in case there are some indirect dependencies
> + * between them).
> + */
> + list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
> + dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST, false);
> +
> + list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
> + dock_remove_acpi_device(dd->handle);
> +}
> +
> +/**
> + * hotplug_dock_devices - Insert devices on a dock station.
> * @ds: the dock station
> - * @event: either bus check or eject request
> + * @event: either bus check or device check request
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> *
> * Some devices on the dock station need to have drivers called
> * to perform hotplug operations after a dock event has occurred.
> @@ -409,24 +429,17 @@ static void hotplug_dock_devices(struct
> {
> struct dock_dependent_device *dd;
>
> - /*
> - * First call driver specific hotplug functions
> - */
> + /* Call driver specific hotplug functions. */
> list_for_each_entry(dd, &ds->dependent_devices, list)
> dock_hotplug_event(dd, event, false);
>
> /*
> - * Now make sure that an acpi_device is created for each
> - * dependent device, or removed if this is an eject request.
> - * This will cause acpi_drivers to be stopped/started if they
> - * exist
> + * Now make sure that an acpi_device is created for each dependent
> + * device. That will cause scan handlers to be attached to device
> + * objects or acpi_drivers to be stopped/started if they are present.
> */
> - list_for_each_entry(dd, &ds->dependent_devices, list) {
> - if (event == ACPI_NOTIFY_EJECT_REQUEST)
> - dock_remove_acpi_device(dd->handle);
> - else
> - dock_create_acpi_device(dd->handle);
> - }
> + list_for_each_entry(dd, &ds->dependent_devices, list)
> + dock_create_acpi_device(dd->handle);
> }
>
> static void dock_event(struct dock_station *ds, u32 event, int num)
> @@ -699,7 +712,7 @@ static int handle_eject_request(struct d
> */
> dock_event(ds, event, UNDOCK_EVENT);
>
> - hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
> + hot_remove_dock_devices(ds);
> undock(ds);
> dock_lock(ds, 0);
> eject_dock(ds);
>
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