On Fri, 17 Feb 2012, Elric Fu wrote:
> The superspeed device attached to a USB 3.0 hub(such as VIA's)
> doesn't respond the address device command after resume. The
> root cause is the superspeed hub will miss the Hub Depth value
> that is used as an offset into the route string to locate the
> bits it uses to determine the downstream port number after
> reset, and all packets can't be routed to the device attached
> to the superspeed hub.
>
> Hub driver sends a Set Hub Depth request to the superspeed hub
> except for USB 3.0 root hub when the hub is initialized and
> doesn't send the request again after reset due to the resume
> process. So moving the code that sends the Set Hub Depth request
> to the superspeed hub from hub_configure() to hub_activate()
> is to cover those situations include initialization and reset.
>
> The patch shoule be backported to kernels as old as 2.6.39.
>
> Signed-off-by: Elric Fu <elricfu1@xxxxxxxxx>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index a0613d8..5b3e918 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -705,10 +705,26 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> if (type == HUB_INIT3)
> goto init3;
>
> - /* After a resume, port power should still be on.
> + /* The superspeed hub except for root hub has to use Hub Depth
> + * value as an offset into the route string to locate the bits
> + * it uses to determine the downstream port number. So hub driver
> + * should send a set hub depth request to superspeed hub after
> + * the superspeed hub is set configuration in initialization or
> + * reset procedure.
> + *
> + * After a resume, port power should still be on.
> * For any other type of activation, turn it on.
> */
> if (type != HUB_RESUME) {
> + if (hdev->parent && hub_is_superspeed(hdev)) {
> + ret = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
> + HUB_SET_DEPTH, USB_RT_HUB,
> + hdev->level - 1, 0, NULL, 0,
> + USB_CTRL_SET_TIMEOUT);
> + if (ret < 0)
> + dev_err(hub->intfdev,
> + "set hub depth failed\n");
> + }
>
> /* Speed up system boot by using a delayed_work for the
> * hub's initial power-up delays. This is pretty awkward
> @@ -987,18 +1003,6 @@ static int hub_configure(struct usb_hub *hub,
> goto fail;
> }
>
> - if (hub_is_superspeed(hdev) && (hdev->parent != NULL)) {
> - ret = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
> - HUB_SET_DEPTH, USB_RT_HUB,
> - hdev->level - 1, 0, NULL, 0,
> - USB_CTRL_SET_TIMEOUT);
> -
> - if (ret < 0) {
> - message = "can't set hub depth";
> - goto fail;
> - }
> - }
> -
> /* Request the entire hub descriptor.
> * hub->descriptor can handle USB_MAXCHILDREN ports,
> * but the hub can/will return fewer bytes here.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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