On Thu, 30 Dec 2010, Sarah Sharp wrote:

quoted text
> Once the xHCI host controller has a USB 2.0 roothub and a USB 3.0 roothub,
> the TT field of the USB 2.0 roothub usb device will no longer be null.

Do you mean the tt field of the root hub usb_hub structure?  It doesn't 
need to be set unless xHCI root hubs really do contain a Transaction 
Translator, and from what you write below I suspect they don't.

quoted text
>  To
> check whether a LS/FS device is plugged into the HS roothub, see if the
> parent's parent is NULL.  We don't need the TT information if the LS/FS
> device is plugged into a roothub port.

Then udev->tt shouldn't be set if udev is plugged into an xHCI root 
hub.  Maybe you should change that instead of changing this.

quoted text
> This bug would only show up after the split roothub code is added.
> 
> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
> ---
>  drivers/usb/host/xhci-mem.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index 1d0f45f..76a9f1c 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -870,9 +870,9 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud
>  	dev->port = top_dev->portnum;
>  	xhci_dbg(xhci, "Set root hub portnum to %d\n", top_dev->portnum);
>  
> -	/* Is this a LS/FS device under a HS hub? */
> +	/* Is this a LS/FS device under an external HS hub? */
>  	if ((udev->speed == USB_SPEED_LOW || udev->speed == USB_SPEED_FULL) &&

These tests are redundant.  udev->tt will not be set unless the speed 
is LOW or FULL.

quoted text
> -			udev->tt) {
> +			udev->parent->parent && udev->tt) {
>  		slot_ctx->tt_info = udev->tt->hub->slot_id;
>  		slot_ctx->tt_info |= udev->ttport << 8;
>  		if (udev->tt->multi)

Alan Stern

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