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)) {
WBR, Sergei
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