On Sat, Feb 18, 2012 at 12:14:26AM +0800, Elric Fu wrote:
> 2012/2/17 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>:
> > 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>
> >
>
> Sorry, I have a little confusion about the Acked-by: and Cc:. I will read
> Documentation/SubmittingPatches carefully again and send V2 patch
> later.
No need to, this just means that Alan agrees with this patch and that
who ever pickes this up for their tree (be it Sarah or me directly),
will add that to the patch and apply it.
You do not need to do anything else here at all.
Sarah, are you going to pick this up, or do you want me to?
thanks,
greg k-h
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