Re: [PATCH v4] usb: dwc3: Wait for control tranfer completed when stopping gadget
From: Felipe Balbi
Date: Mon Oct 17 2016 - 07:55:04 EST
Baolin Wang <baolin.wang@xxxxxxxxxx> writes:
>> Baolin Wang <baolin.wang@xxxxxxxxxx> 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@xxxxxxxxxx>
>> 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?
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