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usb: Check if port status is equal to RxDetect

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When using USB 3.0 pen drive with the [AMD] FCH USB XHCI Controller
[1022:7814], the second hotplugging will experience the USB 3.0 pen
drive is recognized as high-speed device. After bisecting the kernel,
I found the commit number 41e7e056cd
(USB: Allow USB 3.0 ports to be disabled.) causes the bug. After doing
some experiments, the bug can be fixed by avoiding executing the function
hub_usb3_port_disable(). Because the port status with [AMD] FCH USB
XHCI Controlleris [1022:7814] is already in RxDetect
(I tried printing out the port status before setting to Disabled state),
it's reasonable to check the port status before really executing
hub_usb3_port_disable().

Fixes: 41e7e056cd (USB: Allow USB 3.0 ports to be disabled.)
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gavin Guo 2014-07-18 01:12:13 +08:00 committed by Greg Kroah-Hartman
parent 953c664697
commit bb86cf569b
1 changed files with 19 additions and 0 deletions
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19
drivers/usb/core/hub.c
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@ -889,6 +889,25 @@ static int hub_usb3_port_disable(struct usb_hub *hub, int port1)
if (!hub_is_superspeed(hub->hdev))
return -EINVAL;
ret = hub_port_status(hub, port1, &portstatus, &portchange);
if (ret < 0)
return ret;
/*
* USB controller Advanced Micro Devices, Inc. [AMD] FCH USB XHCI
* Controller [1022:7814] will have spurious result making the following
* usb 3.0 device hotplugging route to the 2.0 root hub and recognized
* as high-speed device if we set the usb 3.0 port link state to
* Disabled. Since it's already in USB_SS_PORT_LS_RX_DETECT state, we
* check the state here to avoid the bug.
*/
if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
USB_SS_PORT_LS_RX_DETECT) {
dev_dbg(&hub->ports[port1 - 1]->dev,
"Not disabling port; link state is RxDetect\n");
return ret;
}
ret = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_SS_DISABLED);
if (ret)
return ret;