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usb: Set device removable state based on ACPI USB data

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ACPI offers two methods that allow us to infer whether or not a USB port
is removable. The _PLD method gives us information on whether the port is
"user visible" or not. If that's not present then we can fall back to the
_UPC method which tells us whether or not a port is connectable.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Matthew Garrett 2012-05-11 16:08:28 +08:00 committed by Greg Kroah-Hartman
parent da0af6e78e
commit 54d3f8c63d
1 changed files with 57 additions and 0 deletions
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57
drivers/usb/core/usb-acpi.c
View file

@ -19,6 +19,54 @@
#include "usb.h"
static int usb_acpi_check_upc(struct usb_device *udev, acpi_handle handle)
{
acpi_status status;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *upc;
int ret = 0;
status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
if (ACPI_FAILURE(status))
return -ENODEV;
upc = buffer.pointer;
if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
|| upc->package.count != 4) {
ret = -EINVAL;
goto out;
}
if (upc->package.elements[0].integer.value)
udev->removable = USB_DEVICE_REMOVABLE;
else
udev->removable = USB_DEVICE_FIXED;
out:
kfree(upc);
return ret;
}
static int usb_acpi_check_pld(struct usb_device *udev, acpi_handle handle)
{
acpi_status status;
struct acpi_pld pld;
status = acpi_get_physical_device_location(handle, &pld);
if (ACPI_FAILURE(status))
return -ENODEV;
if (pld.user_visible)
udev->removable = USB_DEVICE_REMOVABLE;
else
udev->removable = USB_DEVICE_FIXED;
return 0;
}
static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
{
struct usb_device *udev;
@ -40,6 +88,15 @@ static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
if (!*handle)
return -ENODEV;
/*
* PLD will tell us whether a port is removable to the user or
* not. If we don't get an answer from PLD (it's not present
* or it's malformed) then try to infer it from UPC. If a
* device isn't connectable then it's probably not removable.
*/
if (usb_acpi_check_pld(udev, *handle) != 0)
usb_acpi_check_upc(udev, *handle);
return 0;
}