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: Sarah Sharp <sarah.a.sharp@linux.intel.com>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c8e0704..100e08f 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -177,6 +177,21 @@
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 @@
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;