2012/3/22 Sergei Shtylyov <sshtylyov@xxxxxxxxxx>:
> On 03/20/2012 11:11 AM, 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(-)
>
>
> I'm afraid this patch won't work correctly on the big-endian machines...
>
>
>> 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)) {
>
>
> 'bcdUSB' is declared as '__le16', so shouldn't there be le16_to_cpu()
> here?
>
> le16_to_cpu(udev->descriptor.bcdUSB) >> 8 != 0x03)) {
>
You are right. I tested it on the big-endian platform just now. I will fix it.
Thanks for your review.
Best Regards,
Elric
> WBR, Sergei
--
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
