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Subject: Re: [PATCH] usb: dwc2: Make sure we disconnect the gadget state
To: John Stultz <john.stultz@linaro.org>,
        lkml <linux-kernel@vger.kernel.org>
References: <1488497779-1894-1-git-send-email-john.stultz@linaro.org>
Cc: Wei Xu <xuwei5@hisilicon.com>, Guodong Xu <guodong.xu@linaro.org>,
        Amit Pundir <amit.pundir@linaro.org>, Rob Herring <robh+dt@kernel.org>,
        John Youn <johnyoun@synopsys.com>,
        Douglas Anderson <dianders@chromium.org>,
        Chen Yu <chenyu56@huawei.com>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org
From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Message-ID: <fd06d128-b88d-b80a-f588-9d47a1ae9fb2@cogentembedded.com>
Date: Fri, 3 Mar 2017 12:18:29 +0300
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Hello!

On 3/3/2017 2:36 AM, John Stultz wrote:

> I had seen some odd behavior with HiKey's usb-gadget interface
> that I finally seemed to have chased down. Basically every other
> time I pluged in the OTG port, the gadget interface would

    Plugged. Perhaps could be fixed while applying...

> properly initialize. The other times, I'd get a big WARN_ON
> in dwc2_hsotg_init_fifo() about the fifo_map not being clear.
>
> Ends up if we don't disconnect the gadget state, the fifo-map
> doesn't get cleared properly, which causes WARN_ON messages and
> also results in the device not properly being setup as a gadget
> every other time the OTG port is connected.
>
> So this patch adds a call to dwc2_hsotg_disconnect() in the
> reset path so the state is properly cleared.
>
> With it, the gadget interface initializes properly on every
> plug in.
>
> Cc: Wei Xu <xuwei5@hisilicon.com>
> Cc: Guodong Xu <guodong.xu@linaro.org>
> Cc: Amit Pundir <amit.pundir@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: John Youn <johnyoun@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: John Youn <johnyoun@synopsys.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
[...]

MBR, Sergei