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USB: Refactor code to set LPM support flag.

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Refactor the code that sets the usb_device flag to indicate the device
support link power management (lpm_capable).  The current code sets
lpm_capable unconditionally if the USB devices have a USB 2.0 Extended
Capabilities Descriptor.  USB 3.0 devices can also have that descriptor,
but the xHCI driver code that uses lpm_capable will not run the USB 2.0
LPM test for devices under the USB 3.0 roothub.  Therefore, it's fine
only set lpm_capable for high speed devices in this refactoring.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This commit is contained in:
Sarah Sharp 2012-02-20 08:31:26 -08:00
parent 448b6eb1e0
commit d9b2099cd6
1 changed files with 17 additions and 5 deletions
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22
drivers/usb/core/hub.c
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@ -177,6 +177,21 @@ static struct usb_hub *hdev_to_hub(struct usb_device *hdev)
return usb_get_intfdata(hdev->actconfig->interface[0]);
}
static int usb_device_supports_lpm(struct usb_device *udev)
{
/* USB 2.1 (and greater) devices indicate LPM support through
* their USB 2.0 Extended Capabilities BOS descriptor.
*/
if (udev->speed == USB_SPEED_HIGH) {
if (udev->bos->ext_cap &&
(USB_LPM_SUPPORT &
le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
return 1;
return 0;
}
return 0;
}
/* USB 2.0 spec Section 11.24.4.5 */
static int get_hub_descriptor(struct usb_device *hdev, void *data)
{
@ -3211,11 +3226,8 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
retval = usb_get_bos_descriptor(udev);
if (!retval) {
if (udev->bos->ext_cap && (USB_LPM_SUPPORT &
le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
udev->lpm_capable = 1;
}
if (!retval)
udev->lpm_capable = usb_device_supports_lpm(udev);
}
retval = 0;