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.
Best Regards,
Elric Fu
--
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
