浏览代码

usb: hub: try old enumeration scheme first for high speed devices

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, and this is what Windows does since Windows 8.

Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Zeng Tao 6 年之前
父节点
当前提交
bd0e6c9614
共有 2 个文件被更改,包括 5 次插入2 次删除
  1. 2 1
      Documentation/admin-guide/kernel-parameters.txt
  2. 3 1
      drivers/usb/core/hub.c

+ 2 - 1
Documentation/admin-guide/kernel-parameters.txt

@@ -4610,7 +4610,8 @@
 
 	usbcore.old_scheme_first=
 			[USB] Start with the old device initialization
-			scheme (default 0 = off).
+			scheme,  applies only to low and full-speed devices
+			 (default 0 = off).
 
 	usbcore.usbfs_memory_mb=
 			[USB] Memory limit (in MB) for buffers allocated by

+ 3 - 1
drivers/usb/core/hub.c

@@ -2661,11 +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?