Hi Balbi,
Do you have any comment for this patch?
Thanks
Jincan
On Wed, May 07, 2014 at 05:53:44PM -0400, Zhuang Jin Can wrote:
> A delayed status request may be queued before composite framework returns
> USB_GADGET_DELAYED_STATUS, because the thread queueing the request can run
> on a different core in parallel with the control request irq.
>
> SETUP XferComplete IRQ fsg_main_thread
> ---------------------- ---------------
> | |
> spin_lock_irqsave(&dwc->lock) sleeping
> | |
> ... ...
> dwc3_ep0_inspect_setup() |
> | |
> dwc3_ep0_delegate_req() |
> | |
> ... |
> spin_unlock(&dwc->lock); |
> | |
> fsg_set_alt() ======> Signal Wakeup ====> |
> | |
> other gadgets->set_alt() handle exception
> | |
> | usb_composite_setup_continue()
> | |
> | spin_lock_irqsave(&dwc->lock)
> | __dwc3_gadget_ep0_queue()
> | delay_status is false
> | spin_unlock_irqrestore(&dwc->lock)
> | |
> | sleeping
> spin_lock(&dwc->lock); |
> | |
> delayed_status=true |
> | |
>
> STATUS XferNotReady IRQ
> ------------------------
> |
> dwc3_ep0_xfernotready()
> |
> delayed_status is true, return;
>
> The result is the status packet will never be transferred, and
> delayed_status is not cleared.
>
> Signed-off-by: Zhuang Jin Can <jin.can.zhuang@xxxxxxxxx>
> Reported-by: Zhou Liping <liping.zhou@xxxxxxxxx>
> ---
> drivers/usb/dwc3/ep0.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index 21a3520..07292c0 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -1020,7 +1020,11 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
> if (dwc->delayed_status) {
> WARN_ON_ONCE(event->endpoint_number != 1);
> dev_vdbg(dwc->dev, "Mass Storage delayed status\n");
> - return;
> +
> + if (list_empty(&dwc->eps[0]->request_list))
> + return;
> + else
> + dwc->delayed_status = false;
> }
>
> dwc3_ep0_do_control_status(dwc, event);
> --
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