The new scheme is required just to support legacy low and full-speed devices. For high speed devices, it will slower the enumeration speed. So in this patch we try the "old" enumeration scheme first for high speed devices. Signed-off-by: Zeng Tao <prime.zeng@xxxxxxxxxxxxx> --- drivers/usb/core/hub.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 1fb2668..d265b19 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2661,10 +2661,13 @@ static bool use_new_scheme(struct usb_device *udev, int retry, int old_scheme_first_port = port_dev->quirks & USB_PORT_QUIRK_OLD_SCHEME; + int quick_enumeration = (udev->speed == USB_SPEED_HIGH); + if (udev->speed >= USB_SPEED_SUPER) return false; - return USE_NEW_SCHEME(retry, old_scheme_first_port || old_scheme_first); + return USE_NEW_SCHEME(retry, old_scheme_first_port || old_scheme_first + || quick_enumeration); } /* Is a USB 3.0 port in the Inactive or Compliance Mode state? -- 2.7.4
