Commit bb86cf56 authored Jul 18, 2014 by Gavin Guo Committed by Greg Kroah-Hartman Jul 17, 2014

usb: Check if port status is equal to RxDetect



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 41e7e056
(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: 41e7e056 (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>

parent 953c6646

drivers/usb/core/hub.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -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;