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ACPI / scan: Indicate to platform when hot remove returns busy 

In hotplug logic, it always indicates non-specific failure to
platform through _OST when handing ACPI hot-remove event failed. Then
platform terminates the hot-remove process but it can not identify
the reason.

Base on current hot-remove code, there have two situations that it
returns busy:

 - OSPM try to offline an individual device, but the device offline
   function returns "busy".

 - When the ejection event is applied to an "not offlined yet"
   container.  OSPM sends a kobject change event to userspace and
   returns "busy".

Both of them will returns -EBUSY to ACPI device hotplug function.
Then, the hotplug function indicates non-specific failure to platform
just like for any other error, e.g. -ENODEV or -EIO.

The benefit to the platform for identifying the OS "busy" state is
that it can use a different approach to handle the "busy" instead of
simply terminating the hot-remove operation for an unknown reason.
For example, the platform can wait for a while and then re-trigger
hot-remove.

Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
[ rjw: Changelog massage ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lee, Chun-Yi 2017-07-03 21:26:10 +08:00 committed by Rafael J. Wysocki
parent 6f7da29041
commit d429e5c122
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/acpi/scan.c
View File

@ -404,10 +404,6 @@ void acpi_device_hotplug(struct acpi_device *adev, u32 src)
error = dock_notify(adev, src);
} else if (adev->flags.hotplug_notify) {
error = acpi_generic_hotplug_event(adev, src);
if (error == -EPERM) {
ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
goto err_out;
}
} else {
int (*notify)(struct acpi_device *, u32);
@ -423,8 +419,20 @@ void acpi_device_hotplug(struct acpi_device *adev, u32 src)
else
goto out;
}
if (!error)
switch (error) {
case 0:
ost_code = ACPI_OST_SC_SUCCESS;
break;
case -EPERM:
ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
break;
case -EBUSY:
ost_code = ACPI_OST_SC_DEVICE_BUSY;
break;
default:
ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
break;
}
err_out:
acpi_evaluate_ost(adev->handle, src, ost_code, NULL);