linux-kernel - Re: [PATCH v2] usb: dwc3: gadget: Stop EP0 transfers during pullup disable

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Date:   Mon, 23 Aug 2021 12:34:07 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Wesley Cheng <wcheng@...eaurora.org>
Cc:     gregkh@...uxfoundation.org, Thinh.Nguyen@...opsys.com,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        jackp@...eaurora.org
Subject: Re: [PATCH v2] usb: dwc3: gadget: Stop EP0 transfers during pullup
 disable


Wesley Cheng <wcheng@...eaurora.org> writes:

> During a USB cable disconnect, or soft disconnect scenario, a pending
> SETUP transaction may not be completed, leading to the following
> error:
>
>     dwc3 a600000.dwc3: timed out waiting for SETUP phase
>
> If this occurs, then the entire pullup disable routine is skipped and
> proper cleanup and halting of the controller does not complete.

nit: might want to add a blank line between paragraphs to aid
readability

> Instead of returning an error (which is ignored from the UDC
> perspective), allow the pullup disable to routine to continue, which
                                         ^^
                                         remove this?

> will also handle disabling of EP0/1.  This will end any active
> transfers as well.  Ensure to clear any delayed_status as well, as the
> timeout could happen within the STATUS stage.
>
> Signed-off-by: Wesley Cheng <wcheng@...eaurora.org>
> ---
> Changes in v2:
>  - Removed calls to dwc3_ep0_end_control_data() and just allow the ep disables
>    on EP0 handle the proper ending of transfers.
>  - Ensure that delayed_status is cleared, as ran into enumeration issues if the
>    SETUP transaction fails on a STATUS stage.  Saw delayed_status == TRUE on the
>    next connect, which blocked further SETUP transactions to be handled.
>
>  drivers/usb/dwc3/gadget.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 5d084542718d..8b6a95c35741 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2430,7 +2430,6 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
>  				msecs_to_jiffies(DWC3_PULL_UP_TIMEOUT));
>  		if (ret == 0) {
>  			dev_err(dwc->dev, "timed out waiting for SETUP phase\n");
> -			return -ETIMEDOUT;
>  		}

Since the `if' now has a single statement, you should remove the curly braces.

-- 
balbi