When the Seagate Goflex USB3.0 device is attached to VIA xHCI host, sometimes the device will downgrade mode to high speed. By the USB analyzer, I found the device finished the link training process and worked at superspeed mode. But the device descriptor got from the device shows the device works at 2.1. It is very strange and seems like the device controller of Seagate Goflex has a little confusion. The first 8 bytes of device descriptor should be: 12 01 00 03 00 00 00 09 But the first 8 bytes of wrong device descriptor are: 12 01 10 02 00 00 00 40 The wrong device descriptor caused the initialization of mass storage failed. After a while, the device would be recognized as a high speed device and works fine. This patch will warm reset the device to fix the issue after finding the bcdUSB field of device descriptor isn't 0x0300 but the speed mode of device is superspeed. Signed-off-by: Elric Fu <elricfu1@xxxxxxxxx> Acked-by: Andiry Xu <Andiry.Xu@xxxxxxx> --- drivers/usb/core/hub.c | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 265c2f6..27ecf27 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -3071,6 +3071,22 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1, if (retval) goto fail; + /* + * Some superspeed devices have finished the link training process + * and attached to a superspeed hub port, but the device descriptor + * got from those devices show they aren't superspeed devices. Warm + * reset the port attached by the devices can fix them. + */ + if ((udev->speed == USB_SPEED_SUPER) && + (udev->descriptor.bcdUSB >> 8 != 0x03)) { + dev_err(&udev->dev, "got a wrong device descriptor, " + "warm reset device\n"); + hub_port_reset(hub, port1, udev, + HUB_BH_RESET_TIME, true); + retval = -EINVAL; + goto fail; + } + if (udev->descriptor.bMaxPacketSize0 == 0xff || udev->speed == USB_SPEED_SUPER) i = 512; -- 1.7.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html