From: Felipe Balbi <balbi@kernel.org>
To: Baolin Wang <baolin.wang@linaro.org>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Mark Brown <broonie@kernel.org>, USB <linux-usb@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4] usb: dwc3: Wait for control tranfer completed when stopping gadget
Date: Mon, 17 Oct 2016 14:53:58 +0300 [thread overview]
Message-ID: <87d1izry21.fsf@linux.intel.com> (raw)
In-Reply-To: <CAMz4kuLpeocJxktHm2NthwWg5LSiNkPByeis555P_Xddb71k3Q@mail.gmail.com>
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Hi,
Baolin Wang <baolin.wang@linaro.org> writes:
>> Baolin Wang <baolin.wang@linaro.org> writes:
>>> When we change the USB function with configfs dynamically, we possibly met this
>>> situation: one core is doing the control transfer, another core is trying to
>>> unregister the USB gadget from userspace, we must wait for completing this
>>> control tranfer, or it will hang the controller to set the DEVCTRLHLT flag.
>>>
>>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>>
>> Can you make sure this still works?
>
> With applying this patch, It can work well on my platform, but I have
> some worries about the risk of accessing 'dwc->ep0state' without lock
> protection in dwc3_gadget_pullup() function.
hmm, I might be missing something, but I think there's no risk here. If
anything, a wmb() is probably enough before reading ep0state. No?
--
balbi
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next prev parent reply other threads:[~2016-10-17 11:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-14 9:11 [PATCH v4] usb: dwc3: Wait for control tranfer completed when stopping gadget Baolin Wang
2016-10-17 10:10 ` Felipe Balbi
2016-10-17 11:47 ` Baolin Wang
2016-10-17 11:53 ` Felipe Balbi [this message]
2016-10-18 2:40 ` Baolin Wang
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