diff options
| author | Zeng Tao <prime.zeng@hisilicon.com> | 2018-09-28 19:27:52 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-02 12:05:30 -0700 |
| commit | bd0e6c9614b95352eb31d0207df16dc156c527fa (patch) | |
| tree | 274c7a7b59d5b149f183371dff221a52f292a9b4 | |
| parent | 2cfe8f864d0e2504dc2f68f0b04668d877f7c7b4 (diff) | |
| download | linux-bd0e6c9614b95352eb31d0207df16dc156c527fa.tar.bz2 | |
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>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 4 |
2 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 92eb1f42240d..151c527571e5 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/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 diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 7801bb30bdba..bf76a3dd4359 100644 --- a/drivers/usb/core/hub.c +++ b/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? |