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Commit d9b2099c authored by Sarah Sharp's avatar Sarah Sharp
Browse files

USB: Refactor code to set LPM support flag. 



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: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent 448b6eb1

drivers/usb/core/hub.c

+17 −5
Original line number Diff line number Diff line
@@ -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;