This is a note to let you know that I've just added the patch titled

usb: dwc2: Improve gadget state disconnection handling

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: usb-dwc2-improve-gadget-state-disconnection-handling.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From d2471d4a24dfbff5e463d382e2c6fec7d7e25a09 Mon Sep 17 00:00:00 2001

From: John Stultz john.stultz@linaro.org Date: Mon, 23 Oct 2017 14:32:48 -0700 Subject: usb: dwc2: Improve gadget state disconnection handling

From: John Stultz john.stultz@linaro.org

commit d2471d4a24dfbff5e463d382e2c6fec7d7e25a09 upstream.

In the earlier commit dad3f793f20f ("usb: dwc2: Make sure we disconnect the gadget state"), I was trying to fix up the fact that we somehow weren't disconnecting the gadget state, so that when the OTG port was plugged in the second time we would get warnings about the state tracking being wrong.

(This seems to be due to a quirk of the HiKey board where we do not ever get any otg interrupts, particularly the session end detected signal. Instead we only see status change interrupt.)

The fix there was somewhat simple, as it just made sure to call dwc2_hsotg_disconnect() before we connected things up in OTG mode, ensuring the state handling didn't throw errors.

But in looking at a different issue I was seeing with UDC state handling, I realized that it would be much better to call dwc2_hsotg_disconnect when we get the state change signal moving to host mode.

Thus, this patch removes the earlier disconnect call I added and moves it (and the needed locking) to the host mode transition.

Cc: Wei Xu xuwei5@hisilicon.com Cc: Guodong Xu guodong.xu@linaro.org Cc: Amit Pundir amit.pundir@linaro.org Cc: YongQin Liu yongqin.liu@linaro.org Cc: John Youn johnyoun@synopsys.com Cc: Minas Harutyunyan Minas.Harutyunyan@synopsys.com Cc: Douglas Anderson dianders@chromium.org Cc: Chen Yu chenyu56@huawei.com Cc: Felipe Balbi felipe.balbi@linux.intel.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org Acked-by: Minas Harutyunyan hminas@synopsys.com Tested-by: Minas Harutyunyan hminas@synopsys.com Signed-off-by: John Stultz john.stultz@linaro.org Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Cc: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/usb/dwc2/hcd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -3220,7 +3220,6 @@ static void dwc2_conn_id_status_change(s dwc2_core_init(hsotg, false); dwc2_enable_global_interrupts(hsotg); spin_lock_irqsave(&hsotg->lock, flags); - dwc2_hsotg_disconnect(hsotg); dwc2_hsotg_core_init_disconnected(hsotg, false); spin_unlock_irqrestore(&hsotg->lock, flags); dwc2_hsotg_core_connect(hsotg); @@ -3238,8 +3237,12 @@ static void dwc2_conn_id_status_change(s if (count > 250) dev_err(hsotg->dev, "Connection id status change timed out\n"); - hsotg->op_state = OTG_STATE_A_HOST;

+ spin_lock_irqsave(&hsotg->lock, flags); + dwc2_hsotg_disconnect(hsotg); + spin_unlock_irqrestore(&hsotg->lock, flags); + + hsotg->op_state = OTG_STATE_A_HOST; /* Initialize the Core for Host mode */ dwc2_core_init(hsotg, false); dwc2_enable_global_interrupts(hsotg);

Patches currently in stable-queue which might be from john.stultz@linaro.org are

queue-4.9/usb-dwc2-improve-gadget-state-disconnection-handling.patch