This patch looks fine. I'm going to wait a week or two to send this bug
fix off to Greg, since he's going to be sending Linus a pull request for
the merge window soon.
Greg, should I hold off or are you willing to take a couple more bug fix
patches to your usb-next queue?
Sarah Sharp
On Tue, Mar 20, 2012 at 04:11:16PM +0800, Elric Fu wrote:
> 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
>
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